Proceedings Volume 7997

Fourth International Seminar on Modern Cutting and Measurement Engineering

Jiezhi Xin, Lianqing Zhu, Zhongyu Wang
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Proceedings Volume 7997

Fourth International Seminar on Modern Cutting and Measurement Engineering

Jiezhi Xin, Lianqing Zhu, Zhongyu Wang
View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 19 May 2011
Contents: 10 Sessions, 136 Papers, 0 Presentations
Conference: Fourth International Seminar on Modern Cutting and Measuring Engineering 2010
Volume Number: 7997

Table of Contents

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Table of Contents

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  • Mechanism and Theories of High Performance Cutting and High Efficiency Grinding
  • Tool Materials and Coating Technologies
  • Computer Applications Technologies of Cutting
  • Green Processing and Manufacturing
  • Cutting of Difficult-to-Machine Materials
  • Theories of Measurement Accuracy and Error
  • Photoelectric Measuring Technologies
  • Signal Analysis and Image Processing
  • Micro- and Nanoprocessing and Measurement
  • Automatic Measurement and Control Technologies
Mechanism and Theories of High Performance Cutting and High Efficiency Grinding
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Study on drilling force and delamination in high speed drilling carbon fiber reinforce plastics (CFRP)
Dong Liu, Xueke Luo, Honghai Xu
The carbon fiber reinforced plastics are highly promising materials which widely used in aerospace industry due to their excellent mechanical properties. The delamination is considered a major problem in manufacture the parts and assembly. The thrust force affected the delamination mostly. This paper investigated the drilling force, torque, delamination of carbon fibred composite with carbide drilling tools and half core drilling tool. The experiments were carried out under air cooling cutting conditions and the drilling force and the damage around the hole using carbide tool and half core tool were compared. The experimental results indicated that the drilling forces using half core drill were smaller than that of using carbide tool and the damages around the drilling hole using half core tool and better than that using carbide drill.
Cutting force modeling and simulation for hole-making process by helical milling
Zhongqun Li, Qiang Liu, Chong Peng, et al.
According to the kinematics of the cutting tool, two different machining operations occur in helical milling operation. One is the plunge milling machined by its front cutting edges resulting from the axial feed of the cutting tool, the other is the peripheral milling machined by its side cutting edges resulting from the tangential feed of the cutting tool. On the basis, both the peripheral and the front cutting depths at each engagement point are derived as a function of cutting parameters using a cylindrical end mill. By dividing the cutting edges into a stack of disks and applying the linear-edge cutting force model to each disk, through coordinate transformation, numerical integration along the cutting edges and summation for the differential cutting forces of all the teeth, the overall instantaneous cutting forces acting on the whole cutting tool in the three orthogonal directions are obtained Based on the cutting force algorithm, the impact of cutting conditions such as the tangential and axial feedrates on the tangential, normal and axial cutting forces is investigated. Meanwhile, a set of cutting trials were conducted to validate the cutting force model. It is shown that the proposed model can well predicate the cutting forces in helical milling. Therefore, the proposed approach is proven to be a feasible and practical approach to determine cutting conditions in helical milling for shop floor applications.
Study on the wear mechanism and tool life of coated gun drill
Yongguo Wang, Xiangping Yan, Xiaoguang Chen, et al.
A comprehensive investigation of the wear progress for solid carbide gun drill coated with TiAlN by machining steel S48CSiV at a cutting speed of 12.66m/s has been performed. Cutting torque was recorded and tool wear mechanism was studied. The surface morphology of the tool and the chip have been studied by using scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). Results show that cutting torque fluctuates between 3% and 5% when machining less than 130 pieces of crankshaft, but it will sharply increased to nearly 18% while machining 150 pieces of crankshaft because the coating is damaged and the wear becoming severity. The dominant wear mechanisms are adhesive wear and chemical dissolution wear.
Research on efficient and stable milling using CNC small size tool
Yongxin Luo, Beichen Zhao, Hua Long, et al.
In order to mill efficiently and stably using small size tool on computer numerical control machine(CNC machine), the paper establishes dual-objective function on the basis of the minimum tool wear and the largest cutting efficiency. Meanwhile, the influence of diameter and length of tool suspended on stability is considered under the guidance of chatter stability analysis relationship. Research results show that, Pareto solution set which has two factors into account conflicting can be obtained by Genetic Algorithms, combined Pareto solution set with the frequency response function (FRF) chatter stability diagram, Pareto solutions of the smaller range of options, the milling parameters which meet the requirements of efficient and stable milling of CNC machine tools can be optimized conveniently and accurately. When the tool suspended length increases, the system stiffness decreases and the chatter stability domain graphic drops down, Stability region narrows.
Workpiece surface quality and the influence factors when high-speed milling of SiCp/2009Al composite
Yingfei Ge, Jiuhua Xu, Yucan Fu
Surface finish, surface generation and the influence factors were investigated when high speed milling SiCp/2009Al composites using polycrystalline diamond (PCD) tools. The results showed that the surface roughness Ra0.207-0.542μm and Rz2.02-5.20μm can be attained when tool flank wear VB is less than 0.09mm under the present cutting conditions. With the increasing wear of the cutting tools, the value of the machined surface roughness significantly increased. The machined surfaces included many defects of pits, voids, microcracks, grooves, protuberances, matrix tearing and smearing and so on. The depth of deformation layers were confined to 20-35μm. Among the factors which affected Ra, reinforcement volume fraction was the most significant factor and followed by cutting speed and feed rate. For the side face, the significance order of the factors which affected Rz can be ranged as reinforcement volume fraction, cutting speed, feed rate and radial depth of cut. Material swelling and side flow, tool-workpiece relative vibration, feed rate and tool nose radius, removal mode of SiC particles were the main mechanisms of surface generation.
Technics study on high accuracy crush dressing and sharpening of diamond grinding wheel
Yunhai Jia, Xuejun Lu, Jiangang Li, et al.
Mechanical grinding of artificial diamond grinding wheel was traditional wheel dressing process. The rotate speed and infeed depth of tool wheel were main technics parameters. The suitable technics parameters of metals-bonded diamond grinding wheel and resin-bonded diamond grinding wheel high accuracy crush dressing were obtained by a mount of experiment in super-hard material wheel dressing grind machine and by analysis of grinding force. In the same time, the effect of machine sharpening and sprinkle granule sharpening was contrasted. These analyses and lots of experiments had extent instruction significance to artificial diamond grinding wheel accuracy crush dressing.
Study on boring hardened materials dryly by ultrasonic vibration cutter
Jiangzhong Zhang, Heng Zhang, Yue Zhang
It has been one of the difficulties that high-precision hole on hardened materials is machined. The supersonic vibration boring acoustic system in the lathe in which supersonic wave energy is applied on tool is introduced to create pulse power on the cutting process. The separation vibration cutting is achieved by the pulse force. The comparative tests on boring accuracy and surface quality are carried. The quality of surface machined by this method is compared to that by grinding. This cutting is the green cutting. The boring process system is stability. Under the condition that the cutting speed is less than or equal to 1/3 the tool vibration speed, the cutting force is pulse force and the Cutting energy is of high concentration in time, space and direction. The pulse energy effects on the cutting unit in less than one ten-thousandth second. Traditional cutting of irregular movement elastic compression are eliminated. The cutting force is greatly reduced. The cutting temperature is at room temperature. The tool life is greatly increased. Shape precision and surface quality is greatly improved. The regulations of the ultrasonic vibration boring dry cutting of hardened material are also summarized. The test results show that the ultrasonic vibration cutting tool boring is of very superior cutting mechanism and is a high-precision deep-hole machining of hardened materials, efficient cutting methods.
Fracture of brazed cemented carbide tool in high speed machining
Hongjie Pei, Yujie Shen, Wei Song, et al.
Although index tools are increasingly used in wide range, brazed carbide tools are extensively applied in all kinds of high speed metal machining for their simple and compact structures, high rigidity and flexibility. So it is important to investigate the tool damage of brazed carbide tools. In the research, to avoid residual stress and micro cracks, the insert trough is specially designed and the parameters of braze-welding and heat treatment are optimized. After being brazed and sharpened, the tools were checked to assure no obvious defects in brazed tools. Then 50 pieces flawless turning tools of 45°, 90° and parting-off, respectively, were selected and used in high speed turning experiments. After turning experiments, there were seven damage types of fracture tools and the main fracture modes were notch, chipping, tip collapse and tip-off for all kinds of tools. Notch damage accounts for about 30% of 45° and 90° fracture tools. Micro tipping and extend-tipping are main fracture modes and in relatively high proportion to the total amount of 45° and 90° straight tools. Tip-off is the main breakage form of cut-off tool and accounting for about 58% of total fracture tools. How the residual stress, micro crack, cutting parameters and material defect, et al, cause tool fracture damage is detailedly analyzed.
Surface-surface interference detection for five-axis machine tool path planning based on triangle subdivision
Feng Lin, Xiaolei Deng
Interference detection between surfaces of the part and the cutting tool is important in 5-axis tool path planning process. The purpose is to ensure the tool in an interference-free posture. There are many ways to detect interference; in this article, the subdivision method is applied. In this research, a simple but high efficiency algorithm based on triangle subdivision has been developed to deal with the two spatial triangles interference detection problems. In the proposed algorithm, only the three vertex coordinates of the two spatial triangles are given. The equation of the plane on which the triangle set lies is then generated, respectively. The intersection line equation can be obtained by combining the two equations. Because of the computer truncation error, errors must have been brought into the obtained line equation. A special method, which is not sensible with the errors of the line equations, is developed to determine whether the intersection line intersects with either of the two triangles. If both are yes, then the intersection points are calculated to further determine whether the two triangles interference by setting a faraway point on the intersection line. The algorithm is efficiency as it concerns only with the solution of two plane equations; and once the none-interference condition satisfies, the algorithm could break from any step.
Friction analysis between tool and chip
Min Wang, Binshi Xu, Jiaying Zhang, et al.
The elastic-plasticity mechanics are applied to analyze the friction between tool and chip. According to the slip-line field theory, a series of theoretical formula and the friction coefficient is derived between the tool and chip. So the cutting process can be investigated. Based on the Orthogonal Cutting Model and the Mohr's circle stress, the cutting mechanism of the cladding and the surface integrity of machining can be studied.
Grinding force model of single abrasive grain based on variable friction coefficient
Jicai Kuai, Huali Zhang, Feihu Zhang
Combined with the grinding principle, it is put forward that friction coefficient changes with the change of grinding parameter; and the grinding force model of single abrasive grain is developed based on friction coefficients of different grinding conditions. Following the theory of variable friction coefficient, the grinding force model of single abrasive grain is theoretically and experimentally researched. The research indicates that this model fully reflects the effects of grinding parameter, abrasive grains' distribution, material properties, variable friction coefficient, and etc. on grinding force of single abrasive grain, which ensure an accurately simulation of actual grinding situation. By using this model, it is predicted that grinding force of single abrasive grain in normal direction has an accuracy of about 18~36.84%; however when taking the variable friction coefficient into consideration, prediction of tangential grinding force of single abrasive grain has an accuracy of about 10~20% by using this model. Experiment proves that this study offered a new grinding force model of single abrasive grain with variable friction coefficient, which has a practical value.
Die surface modification technique by EDM with special pulse power supply
Xiaohai Li, Decheng Wang, Yu Fang, et al.
This paper describes a new method of die surface modification by ordinary Electrical Discharge Machining (EDM) tool. First, the principle of this method is studied. Secondly, the reason for appearance of cracks on the surface of coating layer in the electrical discharge coating with conventional pulse power supply are analyzed. At last, the new type special pulse power supply with additional pulse current is designed. Scenix single-chip is selected as pulse generator, which runs the fastest among all single-chips. The corresponding program can make the pulse power supply produce the additional pulse current. At the same time, the special pulse power supply can communicate different machining parameters with industrial personal computer by serial port of PIC single-chip according to the coating requires, and then PIC single-chip convey machining parameters to Scenix single-chip by the communication interface. Through process experiment, the special pulse power supply for electrical discharge coating behaves well, and the compacted coating layer without cracks deposited on the surface of die by EDM can be obtained, which can prolong the life of die.
Mechanism study on the wear of polycrystalline cubic boron nitride cutting tools
Yunhai Jia, Jiangang Li
The samples of bearing steel, alloy cold-die steel, cold-harden cast iron were continuous machined by polycrystalline cubic boron nitride(PcBN) cutting tools dry turning. After the machining, the phases of cutting tools blade-edge were analyzed by X-ray diffraction analyzer and cutting tools blade-edge microstructure were observed by scanning electronic microscope. And then, the wear mechanism of PcBN cutting tools in turing process was studied. The result showed that the oxidation wear and felt wear were main invalidation factors using PcBN cutting tools dry turning bearing steel and alloy cold-die steel samples; chemical wear and oxidation wear were main invalidation factors using PcBN cutting tools dry turning cold-harden cast iron. In turning process, the granularity of cBN, the heated-stability and chemical characteristic of felt material have key function to cutting tools wear.
Study on relationship between the roughness and the surface function in grinding
Haolin Li, Xingjuan Ying
Surface roughness is a widely used index of product quality and in most cases a technical requirement for mechanical products. Achieving the desired surface quality is of importance for the functional behavior of a part. This paper is aimed at providing current knowledge on the association of surface roughness with function in grinding. Main roughness parameters, adopted by ISO standards or not, are described. The correlation between surface roughness and the desirable function of the surface are discussed. A model is established for describing the generation of the 'ideal' ground surface profile to predict theoretically the work piece roughness. But the model is found to be of limited practical use. It is necessary to adjust the empirical values to the analytical expression obtained in 'ideal' model.
The compound tool of drilling-reaming and rounding chamfer
G. Qian, G. Wei, H. Hua, et al.
In the actual processing, the workstages of spot facingmachining are drilling, reaming, rounding chamfer and so on in milling machine. In large batch production, the workstages are disperse, using more equipments and tools with low working efficiency and high processing cost. And it is difficult to ensure the accuracy of the hole. For these disadvantages, this paper designs a compound tool of spot facingmachining which subjects the drill, reamer and chamfer mill. It can complete three workstages in one setup. And this paper designs the structure of the cutting tool, chooses the material of the cutting part, sets the parameters of cutting part and gives the reference value of cutting parameters. This cutting tool compounds the structure of drill, reamer and chamfer mill, so the manufacturing process is more complex. And this paper also introduces the manufacturing process of the cutting tool in detail. It is rather difficult in designing and manufacturing this spot facingmachining with different compound cutting tool. The existing patents and research are most brazed cutting tool now, and most using different cutting parameters, so has yet to have the same compound tool at present. Practice shows that this cutting tool can greatly enhance the machining accuracy of the hole, collect the machining workstages, reduce the accessorial processing time like changing tool, setting tool and so on, significantly improve the efficiency, reduce the cost and relieve the labour intensity of the workers. In addition, we can change the structure and the material of the cutting tool, and the application of the cutting tool is wide.
Research on the processing speed of cam grinding
Baoying Peng, Qiushi Han
Cam Grinding is a special kind of non-circular machining. The processing speed of cam grinding has a major influence on cam machining precision. In this paper, decomposed the X-axis feed speed and C-axis velocity by the tangential speed and normal speed in accordance with the curvature circle at the point of cam profile grinding. Proposed the cam grinding processing speed model and linear velocity calculation formula, the processing experiment on the CNC camshaft grinding machine results show that the cam grinding speed model is correct. Constant angular speed grinding and constant linear speed grinding are analyzed respectively, which provides a theoretical basis for cam grinding processing speed optimization.
Research on abrasion law of coated cutters for high-speed dry milling
Youdan Guo
The application of dry milling technology has completely eliminated the pollution of cutting fluid in machining. However, dry milling sets very high requirements on milling process and milling cutters, which has become the bottleneck in the popularization of dry milling technology. This research on the abrasion mechanism of TiAlN coated cutters for high-speed dry milling has indicated that, in high-speed dry milling, the abrasion of coated cutter is mainly in the form of crater. TiAlN coating has very strong oxidation resistance and adhesion resistance, so that the cutters have good abrasion resistance and crater abrasion resistance. In high-speed dry milling, a very thin layer of amorphous Al2O3 will be formed on the surface of TiAlN coating, forming hard inert protection film that acts as a good heat barrier. TiAlN coating has a low friction coefficient, which can effectively reduce the cutting force and cutting temperature, thus greatly prolonging the life of cutter. As an emerging coated cutter, TiAlN coated cutters exhibit incomparable excellent performance in high-speed dry milling. The research shows that factors such as coating thickness, milling speed, chip thickness and cutter conditions have important impact on the abrasion of TiAlN coated cutters.
Study on accurate tool wear monitoring based on acoustic emission signal
Yinhu Cui, Guofeng Wang, Dongbiao Peng, et al.
This paper presents an experimental study of the application of acoustic emission (AE) signal for tool wear monitoring in the milling of Ti-6Al-4V alloy. Experiments were conducted and the corresponding AE signals were captured under different tool wear status. Initial analysis reveals that the AE signal contains useful information about the mechanism of the tool wear and can reflect the changing of the cutting parameters as well which show that the AE signal can be used as a reliable means for accurate tool wear monitoring. The comparison with other kinds of sensor signals also shows that the AE signal is more suitable for online tool wear monitoring in industrial environment. Based on these conclusions, AE signal can be used as a reliable signal for accurate tool wear monitoring.
Tool Materials and Coating Technologies
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Cutting insert and work piece materials for minimum quantity lubrication
Sheri Kurgin, Gary Barber, Qian Zou
There is considerable interest in utilizing either dry or minimum quantity lubrication (MQL) as an alternative to flood cooling due to environmental concerns with flood coolant such as excessive misting and disposal of the used coolant. Dry machining can result in high tool wear and also built up edge problems on the cutting tool. The objective of this research was to study the effect of work piece material and tool material on the machining characteristics, in this case reaming, of aluminum using MQL. In particular, a high tin casting and three different tool materials: carbide, DLC and PCD were studied. The high tin casting was found to produce lower cutting temperature and lower spindle power. The PCD coated insert performed the best in terms of lowest temperature rise, lowest spindle power and highest part quality.
Self-propagating high-temperature synthesis brazing for emergency repair
Yang Bai, Zhen Luo, Naifeng Fan, et al.
It is of great significance to fast weld and repair damaged parts in electroless and gasless field. So, based on Selfpropagating High-temperature Synthesis (SHS), this paper investigates the SHS brazing of thermit reaction. It is found that the heat obtained by SHS thermit reaction can not melt the base metal, however the silver solder with the melting temperature of 595°C to 605°C can all just melt in the middle of the base metal to achieve SHS brazing. In the experiment, as the surface tension, the molten solder is more likely to wet the slag which is with a larger surface tension, resulting in the poor wettability between solder and base metal. By adding a certain amount of silver brazing flux into the powder can solve the problem of base metal wetting. When the silver brazing flux and the powder are in a ratio of 10:1, solder melt completely, and can be separated with slag, there is a good weld surface. With the increase of silver brazing flux, the slag is more loose and easy to removal. The solder and base metal coating is better. However, with further increase in silver brazing flux, the heat from the reaction reduces, solder can not melt. And with the increase of the powder, the slag and the solder can not be separated. SHS brazing combines the thermit reaction heat with the brazing technology to achieve the low carbon steel welding. Using the heat of thermit reaction to melt the solder then weld the steel can overcome the defects of poor quality of traditional welding which use the reaction products. And the operation is simple. SHS brazing achieve the emergency equipment welding under the condition of no electricity, no gas and equipment.
Effects of technological parameters on microstructure and properties of CrAlN coating deposited by DC magnetron sputtering
Lihong Yang, Kangpei Zheng, Ping Liu, et al.
In this paper, the deposition processes of CrAlN coatings on high speed steel (M2) substrate was mainly researched, which made by reactive direct current (DC) magnetron sputtering with AlCr alloy target. The effects of technological parameters (Ar/N2 flow ratio, gas pressure and substrate temperature) on the microstructure and properties of CrAlN coatings were systematically studied with scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrum (EDS) and nano-indentation techniques. The results indicated that Ar/N2 flow rate, gas pressure and substrate temperature greatly influenced the microstructure and properties of CrAlN coatings. With Ar/N2 flow ratio of 1, gas pressure of 0.2Pa and substrate temperature of 300°C, the hardness and elastic modulus of CrAlN coating were 34.8GPa and 434.3GPa respectively.
Review on advanced composite materials boring mechanism and tools
Runping Shi, Chengyong Wang
With the rapid development of aviation and aerospace manufacturing technology, advanced composite materials represented by carbon fibre reinforced plastics (CFRP) and super hybrid composites (fibre/metal plates) are more and more widely applied. The fibres are mainly carbon fibre, boron fibre, Aramid fiber and Sic fibre. The matrixes are resin matrix, metal matrix and ceramic matrix. Advanced composite materials have higher specific strength and higher specific modulus than glass fibre reinforced resin composites of the 1st generation. They are widely used in aviation and aerospace industry due to their high specific strength, high specific modulus, excellent ductility, anticorrosion, heat-insulation, sound-insulation, shock absorption and high&low temperature resistance. They are used for radomes, inlets, airfoils(fuel tank included), flap, aileron, vertical tail, horizontal tail, air brake, skin, baseboards and tails, etc. Its hardness is up to 62~65HRC. The holes are greatly affected by the fibre laminates direction of carbon fibre reinforced composite material due to its anisotropy when drilling in unidirectional laminates. There are burrs, splits at the exit because of stress concentration. Besides there is delamination and the hole is prone to be smaller. Burrs are caused by poor sharpness of cutting edge, delamination, tearing, splitting are caused by the great stress caused by high thrust force. Poorer sharpness of cutting edge leads to lower cutting performance and higher drilling force at the same time. The present research focuses on the interrelation between rotation speed, feed, drill's geometry, drill life, cutting mode, tools material etc. and thrust force. At the same time, holes quantity and holes making difficulty of composites have also increased. It requires high performance drills which won't bring out defects and have long tool life. It has become a trend to develop super hard material tools and tools with special geometry for drilling composite materials.
Effect of VC/TaC on W-Ti-Co ultrafine cemented carbides
Chongcai Zhang, Feiou Wu, Bo Zeng, et al.
The ultrafine WC-14wt%TiC-8wt%Co (YT14) powders doped different vanadium carbide and tantalum carbide (VC/TaC) content with an average particle size of 270nm were prepared by 72 hours high-energy ball milling. The VC/TaC content was 0%, (0.3VC+0.5TaC) wt%, (0.4VC+0.4TaC) wt%, (0.5VC+0.3TaC) wt% respectively. VC/TaC had disadvantage influence on cubage contraction and density of YT14, but promoted transverse rupture strength (TRS) and refined grain size. When the VC/TaC content was (0.4VC+0.4TaC) wt%, combination property of alloy was best, the density was 11.26 g·cm-3, the hardness was 92.6HRA, the TRS was 1520MPa, the average grain size was 0.6μm.
Effect of VC on W-Ti-Co ultrafine cemented carbides
Chongcai Zhang, Bo Zeng, Feiou Wu, et al.
The ultrafine WC-14wt%TiC-8wt%Co powders doped different vanadium carbide(VC) content with an average particle size of 270nm were prepared by 72 hours high-energy ball milling. The VC content ranged from 0wt% to 1wt%. The powder was cold isostatic pressed at 280MPa and vacuum sintered at 1380°C. The physical properties and the micrographs of samples were detected. The main conclusions were as follow: the coercivity and hardness increased and the density and Cobalt magnetic decreased with the content of VC increasing; the hardness of alloy with 0.8wt% VC reached 91.8HRA.When the content of VC was less than 0.6wt%, the transverse rupture strength (TRS) increased; the content surpassed 0.8wt%, the TRS was lower than the one without VC. The VC could inhibited the growth of WC grain and the average grain size of WC with 0.8wt% VC was 0.7μm.
Computer Applications Technologies of Cutting
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Research on CNC grinding for planar cutting inserts with various linetypes
Fei Li, Bin Yao, Yuanyuan Wang, et al.
Grinding of the cutter-edge of the planar cutting inserts with rake angle at zero and various linetypes is mainly carried out on the flank face. In order to realize CNC (Computer Numerical Control) Grinding, a model of cutting-edge curves is given, and the cutting locations are obtained. Further, by using macro programs, online measuring of the cutting location and the automatic machining programs are generated rapidly. The paper mainly analyses the three factors mentioned above by the theory and the experiment. The test results proved that the proposed method can satisfy the requirement for product accuracy and increase the machining efficiency about 50%.
Methods of searching and analyzing the data of the gear tooth profile in gear cutter CAD
Xing-hua Pang, Er-hua Wang
In gear-cutter CAD(Computer Aided Design), certain points belonging to series cutter loci which were generated by the simulation of the cutting process may form a gear-tooth profile. Finding out such points and analyzing them to predict the properties of a new gear is also a very important step which determines the succedent analyzing steps. However, the problem of abstracting these data from the loci rapidly and accurately remains to be solved. The two algorithms presented in this paper, concentric-arcs searching and revolving-scan searching, would provide theoretic basis for the on-line gear-tooth analysis. The former focuses on drawing concentric-arcs between the dedendum and addendum of the gear, the latter concentrates on drawing radial lines between two angles.Such arcs and lines will intersect one or more lines of the cutter profile.Correspongding screening criterions will greatly contribute to juge and identify useful intersections which may form the gear profile, and the gear-tooth shape analysis will be carried out as a result. Keyword: gear cutter; CAD; concentric-arcs searching; revolving-scan searching.
Machining fixture layout optimization using particle swarm optimization algorithm
Jianping Dou, Xingsong Wang, Lei Wang
Optimization of fixture layout (locator and clamp locations) is critical to reduce geometric error of the workpiece during machining process. In this paper, the application of particle swarm optimization (PSO) algorithm is presented to minimize the workpiece deformation in the machining region. A PSO based approach is developed to optimize fixture layout through integrating ANSYS parametric design language (APDL) of finite element analysis to compute the objective function for a given fixture layout. Particle library approach is used to decrease the total computation time. The computational experiment of 2D case shows that the numbers of function evaluations are decreased about 96%. Case study illustrates the effectiveness and efficiency of the PSO based optimization approach.
Modeling and simulation of multilevel current source inverter based on SIMetrix/SIMPLIS
Jianyu Bao, Weibing Bao, Weizhong Fang, et al.
Based on analysis of operational principle of single-phase multilevel current source inverter (MCSI), a novel method for modeling and simulation of MCSI system was proposed. In SIMetrix/SIMPLIS, the simulation model of a kind of singlephase 5-level CSI was developed by using hierarchy design. In the control system, the multi-carrier PWM modulation strategy was adopted, the current balance control for intermediate DC-link inductor was implemented on the principle of redundant switching combinations. The reasonability and validity were testified by the coincidence of the simulation results and theoretical analysis. This novel method is also suitable for modeling other power electronics inverters and offers a new thinking for designing actual power electronic circuits.
Simulation of cutting process in the cable recycling system
Yang Li, Zhen Luo, Kailei Song, et al.
The utilization of Waste Electrical and Electronic Equipment is a hot spot in environmental protection field presently and the resource utilization of cable wastes is an important subject. An enormous amount of electrical cable is disposed of as scrap each year. In order to recycle the valuable copper wires, cable granulator technique is used widely. However, one of the shortcomings of this technique is it has serious tool wear. In order to better understand the reason for tool wear, this paper simulates the stress and strain distribution in the cutting tool and copper during the cutting process in cable granulator by finite element method. The result shows that a tensile stress region, which is the main reason for blade tipping, appeared in the upper blade. Besides, the tensile stress in the right side of upper blade is higher than that in the left side. Therefore, in order to extend the life of cutter, we suggest using different materials in different stress zone to manufacture cutting tool. After the cutter was worn out, the right side of the blade can be renovated using material with well tensile performance through overlaying welding, as well as the left side of the blade can be renovated by material with high red hardness, high wear resistance, and high compression strength through overlaying welding. This method can reduce the consumption of precious metals and raise the utilization rate of materials.
A tool management system based on RFID
Z. G. Wang, L. D. Xu, D. S. Cai
Built the RFID (Radio Frequency Identification) hardware system then developed a tool management system based on Labview in the paper. The software can control the read/write device to read/write data through the serial port and use the database management module to add, query, modify and delete record. So, the automatic identification and management of cutting tool is realized.
Optimal machining parameters module development based on CAD/CAM system
Jinichun Zhang, Xiansheng Gong, Guanghui Xie, et al.
In view of the actual numerical control processing in cutting specifications' establishment question, take Windows as the service platform, used the grid algorithm and using VC6.0, MFC (the Microsoft foundation class) and tool research and so on C-HOOKS has developed with the MasterCAM seamless integration cutting specifications optimization module. Carries on the practical application which on the numerical control milling machine to the connecting rod mold electrode the cutting specifications optimize to indicate that through the optimization, obtained the small depth of cut and the roughing feed speed combination, the connecting rod electrode surface has pulls out the mold ascent, used the small depth of cut to enable the electrode surface to obtain the good smooth finish, its machining time saved 49%, the processing efficiency obtains the large scale promotion nearly, the product quality has the enhancement.
Finger milling-cutter CNC generating hypoid pinion tooth surfaces based on modified-roll method and machining simulation
Genggeng Li, Xiaozhong Deng, Bingyang Wei, et al.
The two coordinate systems of cradle-type hypoid generator and free-form CNC machine tool by application disc milling-cutter to generate hypoid pinion tooth surfaces based on the modified-roll method were set up, respectively, and transformation principle and method for machine-tool settings between the two coordinate systems was studied. It was presented that finger milling-cutter was mounted on imagined disc milling-cutter and its motion was controlled directly by CNC shafts to replace disc milling-cutter blades effective cutting motion. Finger milling-cutter generation accomplished by ordered circular interpolation was determined, and interpolation center, starting and ending were worked out. Finally, a hypoid pinion was virtually machined by using CNC machining simulation software VERICUT.
New modeling method of spiral bevel gears with spherical involute based on CATIA
Zhaobin Hong, Zhaojun Yang, Xuecheng Zhang, et al.
Based on the generating principle of generating line of spiral bevel gears with spherical involute, a new method for building the model of spiral bevel gears with spherical involute is presented by utilizing the modules of part design, assembly design and kinematic simulation in CATIA. In the part design module of CATIA, the models of base cone, tangent surface, and generating line are built respectively. And the built models are assembled in the assembly environment; the simulation of pure rolling is accomplished in the environment of kinematics; and the model of the gear surface is built using the function of tracks. Then the solid model of the spiral bevel gear is built through the functions of transferring the model's file format, multi-section sweep and solid fill. Finally, the analysis to the performance of the bevel gear transmission is conducted. In the environment of the assembly design, the solid model of the gearwheel and the pinion are inserted respectively, and then the assembly is accomplished by applying the constraints. And in the environment of kinematics, the meshing simulation of the bevel gear pair is accomplished by applying angle drive. The research indicates that this method can build the model of spiral bevel gears accurately and rapidly, and the model can illustrate the gearing correctly.
Helical surface reconstruction based on CMM
Zhikang Pan, Lianqing Zhu, Qingshan Chen, et al.
The reconstruction of helical surface plays an important role in many engineering and scientific applications. This paper tends to establish an effective processing scheme of surface reconstruction of scatter 3D points, and make an in-depth exploration for the preprocessing technology of scatter points set and the algorithm of three-dimension model surface reconstruction. This paper has three main aspects: data acquisition, data preprocess and surface reconstruction. First, by comparing several measuring equipments, the screw parts are scanned via CMM (Coordinate Measuring Machine). Initial 3D point clouds are obtained by setting the scanning route according to the shape of the targets. Second, Using "3σ" criteria point de-noising is applied to the initial data points. Then Heap Sort is used to sort these points, being convenient for saving data and reconstructing the surface. Third, this paper presents a surface reconstruction method based on triangulation algorithm. The triangular meshes are generated based on Delaunay triangulation technique in two dimensions. And Loop Subdivision is adopted in order to get manifold meshes. Finally the surface reconstruction of an involute worm and an Archimedes worm shows that this approach is feasible.
Research on the thermal load of CNC milling machine
Xue-Jun Nie, Ping-Dong Wu
Machine tool accuracy is the assurance of top-quality products in machining processes. In the all kinds of errors related to machine tools, thermal errors of machine tools' parts play an important role in machining accuracy and directly influence both the surface finish and the geometric shape of the finished workpiece. Therefore the objective of this work was to analyze the temperature field and thermal deformation in some parts of CNC machine tools. In this paper, the thermal boundary condition of main spindle and driving ball screw in CNC milling machine are discussed, some parameters in heat transfer process are calculated. Based on steady heat transfer process, the thermal analysis about spindle and ball screw is carried out under ANSYS environment, and their temperature fields are obtained when milling machine is working. Then the deformations of main spindle and ball screw are acquired by applying the thermal structure coupling element. Furthermore, in order to decrease main parts' deformations and improve the accuracy of CNC milling machine, some suggests are proposed.
Optimization design of chip removal structure in the deep-hole drilling based on CAD/CFD
Yindong Zhang, Hongpeng Zhang, Yulong Ji, et al.
The chip removal structure is very important in deep-hole machining and has great influence on drilling efficiency. The method of CAD/CFD is presented to optimize design parameters of the chip removal structure in the paper. Because the shape of front nozzle in the chip removal structure is the key, so the radius of front nozzle is chosen to be an optimized object. Then, the CAD technology is applied to build a series of three-dimensional parameterization models of the chip removal structure with different front nozzle radius, and CFD software FLUENT is used to calculate three-dimensional flow field in the every built model. Subsequently, several evaluation indexes which can indicate performance of the chip removal structure are established and the calculation results of every inner flow field in the model are evaluated by the synthesis of Analytic Hierarchy Process and Fuzzy Comprehensive Evaluation. Finally, the chip removal structure with optimum front nozzle radius is achieved.
Simulation and experimental research on modal analysis for a new 5-axis superalloy blade machine tool
H. P. Zhao, X. Q. Tang, X. Chen, et al.
This paper considers a new type of 5-axis machine tool which is used to cut superalloy blades specially. Referring to this new structure system, this study presents modal simulation in detail to calculate the structure vibration resistance. The modal simulation include building suitable finite element models, considering boundary constraints and interpreting results. The physical impact test of prototype is conducted to validate the simulation results. The modal simulation also reveals that some important partial characteristics that affects the structure performance are ignored in the physical test data. The validated model can be used to complement the experimental test.
The study of opened CNC system of turning-grinding composite machine tool based on UMAC
Hongjun Wang, Qiushi Han, Guoxin Wu, et al.
The general function analysis of a turning-grinding composite machine tool (TGCM) is done. The structure of the TGCM based on 'process integration with one setup' theory in this paper is presented. The CNC system functions of TGCM are analyzed and the CNC framework of TGCM is discussed. Finally the opened-CNC system for this machine tool is developed based on UMAC (Universal Motion and Automation Controller) included hardware system and software system. The hardware structure layout is put forward and the software system is implemented by using VC++6.0. The hardware system was composed of IPC and UMAC. The general control system meets the requirement of integrity machining and matches the hardware structure system of TGCM. The practical machining experiment results showed that the system is valid with high accuracy and high reliability.
Green Processing and Manufacturing
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Superplastic micro backward extrusion of Zr65 based bulk metallic glass for microparts
Rong Cheng, Xiao Wu, Jianjun Li, et al.
This study seeks to establish microforming technologies for complex-shaped micro-parts which require multi-axial flow of material. For this purpose, it is important to develop new methods to fabricate micro-moulds and to select suitable materials and processing technology for microforming. 4Cr5MoSiV1 has been used to fabricate micro-moulds and Zr65Cu15Ni10Al10 bulk metallic glass has been employed in micro backward extrusion. Our research has demonstrated: (1) The die mounting base which inner trapezoidal holes has been used instead of the conventional mould would reduce the mould weight and simplify the processing technology. (2) The Zr65Cu15Ni10Al10 BMG flow strain rate decreases significantly with punch diameter and punch speed decreasing in the supercooled liquid region, but low strain rate resulting the extended processing time will cause crystallization phenomenon. (3) Excellent extruding results were obtained under the punch speed of 8×10-3 mm/s at 703 K, the maximum punch load of 1200 N, the punch size of &nullset; 1.0mm and no pressure holding time.
Improving dimensional accuracy of SLS processed part using Taguchi method
Rong Cheng, Xiaoyu Wu, Jianping Zheng
This paper presents experimental investigations on influence of important process parameters: laser power, scan speed, layer thickness, hatching space along with their interactions on dimensional accuracy of Selective Laser Sintering (SLS) processed pro-coated sand mold. It is observed that dimensional error is dominant along length and width direction of built mold. Optimum parameters setting to minimize percentage change in length and width of standard test specimen have been found out using Taguchi's parameter design. Optimum process conditions are obtained by analysis of variance (ANOVA) is used to understand the significance of process variables affecting dimension accuracy. Scan speed and hatching space are found to be most significant process variables influencing the dimension accuracy in length and width. And laser power and layer thickness are less influence on the dimension accuracy. The optimum processing parameters are attained in this paper: laser power 11 W; scan speed 1200 mm/s; layer thickness 0.5 mm and hatching space 0.25 mm. It has been shown that, on average, the dimensional accuracy under this processing parameters combination could be improved by approximately up to 25% compared to other processing parameters combinations.
Cutting of Difficult-to-Machine Materials
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Study on the cutting mechanism and the brittle ductile transition model of isotropic pyrolyric graphite
Minghai Wang, Zhonghai Liu
Isotropic pyrolyric graphite (IPG) is a new kind of brittle material, it can be used for sealing the aero-engine turbine shaft and the ethylene high-temperature equipment. It not only has the general advantages of ordinal carbonaceous materials such as high temperature resistance, lubrication and abrasion resistance, but also has the advantages of impermeability and machinability that carbon/carbon composite doesn't have. Therefore, it has broad prospects for development. Mechanism of brittle-ductile transition of IPG is the foundation of precision cutting while the plastic deformation of IPG is the essential and the most important mechanical behavior of precision cutting. Using the theory of strain gradient, the mechanism of this material removal during the precision cutting is analyzed. The critical cutting thickness of IPG is calculated for the first time. Furthermore, the cutting process parameters such as cutting depth, feed rate which corresponding to the scale of brittle-ductile transition deformation of IPG are calculated. In the end, based on the theory of micromechanics, the deformation behaviors of IPG such as brittle fracture, plastic deformation and mutual transformation process are all simulated under the Sih.G.C fracture criterion. The condition of the simulation is that the material under the pressure-shear loading conditions .The result shows that the best angle during the IPG precision cutting is -30°. The theoretical analysis and the simulation result are validated by precision cutting experiments.
An experimental study of machinability of FGH95 in end milling with coated carbide tools
Jin Du, Chao Tan
FGH95 is one of difficult-to-cut nickel-based powder metallurgy (PM) superalloys which are commonly used in advanced turbo-engines. Firstly, this paper presents an orthogonal design experiments to study the cutting force and cutting temperature variations in the end milling of FGH95 with two kinds of coated carbide tools. It is found that AlTiN coated solid carbide end mill is suit for machining FGH95 nickel-based powder metallurgy superalloy. Experimental results show that with the increase of cutting speed, radial depth of cut, feed rate, there is a growing tendency in cutting forces. Among the cutting condition parameters, cutting speed has the greatest influence on cutting forces, especially when cutting speed exceeds 55m/min. With the increase of cutting speed and radial depth of cut, cutting temperature increases. However the cutting temperature decreases slightly as the increasing of feed rate. Reason for temperature variations is investigated in this paper. Secondly, tool wear mechanism in end milling of FGH95 is analyzed. It is shown that chipping on cutting edge is the most dominate wear mechanism which dominates the deterioration and final failure of the coated carbide tools. Thirdly, the machined surface topography is measured with white light interferometer and Super depth digital microscope. Based on the measurement, it is found that better surface roughness and waviness are obtained with using AlTiN coated carbide tools than by TiAlN/TiN/TiAlN coated ones.
Investigation of vibration tapping torque characteristics though mechanistic modeling and experimentation
Baolin Yin, Rongdi Han, Ying Yu, et al.
This paper deals with theoretical and experimental investigation into the processing parameters which influence the tapping torque in vibration tapping. Theoretic analysis with fracture mechanics indicates that the pulsating cutting force effect of the tap on the workpiece results in stress increasing, which leads to reduced cutting forces and a much lower tapping torque. And the effect of the increasing stress would decays gradually with increasing cutting distances. Theoretical analyzers have been developed to the relationship between tapping torque and torsional angle amplitude and net cutting time ration in vibration tapping. Large quantity experiments of vibration tapping in different materials with different thread dimension have be introduced. The thread dimension range M3 to M6, and materials of test include C45 steel, 1Cr18Ni9Ti, TC4 and GH4169. Tapping torque wave was measured in vibration tapping. And the experiments were conducted to compare the fluctuation tapping torque with different cutting distance. Experimental results showed that tapping torque would increase with increasing of torsional angle amplitude and net cutting time ration in vibration tapping. And the theoretical results are confirmed by experiments.
Study on on-line monitoring of surface quality for milling heat assistance alloy
Dongbiao Peng, Guofeng Wang, Yinhu Cui, et al.
In this paper, a complete framework is proposed to realize on-line monitoring of surface quality based on machining mechanism and multi-sensor fusion. Off-line experiments and on-line modeling are integrated together to obtain the effective features to characterize the relation between the surface quality and sensor information. Vibration, force and acoustic emission signal are selected and different sensors are mounted to obtain enough information from the machining process. In addition, parametric and non parametric methods are used to extract the features which are sensitive to surface quality and insensitive to the cutting parameters. After the features are selected, methods based on hybrid intelligence are presented to build the relationship between the surface quality and the corresponding features. The establishment of the whole framework provides an effective means to realize the online monitoring of surface quality during the milling process.
Theories of Measurement Accuracy and Error
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New way for accuracy measurement of fine-pitch gears in batch production
Huakun Xie, Ying Fu, Gang Feng, et al.
Fine-pitch gears with module ranging from 0.05 to 0.5 are widely used in the fields of dial indicators, aeronautic gauges and instruments, timers and watches and so on; but because of their small size and weak rigidity and small aount of inertia, so far there are few methods in practice being able to meet the requirements of their reliable, precise and efficient accuracy measurements, especially in batch production. Based on the gear integrated error measuring technology and the gear single flank rolling tester, a differential type of gear single flank point rolling scan measuring technique and a prototype of the gear differential single flank rolling tester have been developed to explore a new way to solve the problem. By using a special made master gear, the tester can perform not only the measurement of the gear tangential composite deviations but also the measurement of the gear elementary deviations, including profile deviations and pitch deviations, and also integrated deviatons of fine-pitch gears in batch production with high efficiency and accuracy. The conception of "Two spindles be driven in synchronization, and one differential measurement be in closed loop" and the design structure of "spindle on spindle" adopted by the prototype are introduced in the paper. Some practical measurement results in factory and a few discussions are also presented.
Mechanical bearing bore similarity law of non-thermal deformation
Enming Miao, Pengcheng Niu, Xianrui Ji, et al.
The gear transmission is widely used in mechanical engineering. During the work time, the size of the bearing hole has changed due to temperature increase, leading to the size, shape and position tolerances of shaft and bearing with the components deviates from the original design requirements, thus making the spatial location of axis , gear with the gap and tooth contact angle changed, noise increasing, gear life shorten. In this paper, the thermal deformation experiments of the commonly used mechanical engineering machinery bearing hole has been carrying on. Using self-developed experimental device, in the -10 ~ 80°C temperature range, a single hole is measured accurately on the different radial direct, and measurement data is analyzed, combined with the structure and size of surrounding of hole. The results of theory and test analysis show that the thermal deformation feature of hole is not only closely related to the physical attributes of material, but still affected by its own structure and size of parts. That means thermal deformation of parts has non-similar thermal deformation features.
Application of time series to thermal error compensation of machine tools
Enming Miao, Yan Yan, Yetai Fei
The thermal error compensation of CNC machine tool is of great value to improving the accuracy, and the modeling method is a proximate factor of thermal error compensation and its robustness. Currently, internationally adopted modeling methods include multiple linear regression, neural network method etc. And the most commonly used modeling method is multiple linear regression, what is simple and quick. But forecast accuracy which needs to be improved limits to the application of thermal error modeling of precision CNC machine. When we model a time series modeling, we study variables and its extrapolate mechanism to forecast changes of time series, give heavier weight to the data near by the prediction, increase short-term parameters' impact of model, so as to achieve improving forecasting precision of model. And time series models have been used widely in economic, sociology and medicine, but few in thermal error modeling of CNC machine. Adopt autoregressive distributed lag model of time series analysis, and contract of results among time series model, multiple linear regression model, demonstrate that forecast accuracy can be improved using time series model, and time series analysis has a bright future.
A novel method of gross error identification in non-diffracting beam triangulation measurement system
Zhongyu Wang, Qian Wang, Xue Wang
In the small sample problem, the data distribution is unknown and the traditional methods are complicated. In order to address the small sample problem, it combines the grey accumulated generating operation with the GM (1, 1) model in this article. This method is applied in the non-diffracting beam triangulation measurement system and compared with the original methods. The result shows that the novel method can remove the abnormal data reasonably and quickly. In the large sample problem, the new method can gain the same result as the statistical methods. In the small sample problem, the proposed method can overcome the shortages of the existing evaluation methods and can be one of complements for the original methods.
A data prediction method under small sample condition by combining neural network and grey system methods
Jihua Fu, Jie Tong, Qian Wang, et al.
Data prediction is one of the key problems for precision measurement and control. The data obtained by measuring system are often limited. To solve the small sample problem, the BP neural network methods are widely used. However, because of too many input factors and complex data training process, the convergence speed of the BP neural network method is slow. To increase the convergence speed, some grey relational analysis methods were introduced into the BP neural network methods. The grey relational coefficients were calculated first. And by sorting the grey relational coefficients, some factors with less relationship were removed form the BP neural network's inputs. Through the preliminary theory and experiment analysis, the data prediction under small sample could be fulfilled in accuracy and with high convergence speed.
A method of robot parameters rapid error compensation for online flexible measurement system
Changjie Liu, Zhongkai Zhang, Yiwei Chen
When the industrial robot is running continuously on-field, the parameters of robot will change because of the effect of robot's self-heat and the changes of the external environment. The repeating position-setting accuracy will reduce, it has great effect on the accuracy of robot flexible coordinate measuring system, which uses industrial robot as the means of delivery, thus the compensation should be adopted. This article shows a rapid robot parameters calibration technology that is based on the constant robot space distance. Through the measurement of the multiple and the same space distance in measurement period, and according to the robot motion model, it solves the changeable parameters of the robot quickly and reverse, and solves the measurement error caused by the robot's parameter variation, and then compensates the final measuring results. Experiments proved that this solution can improve system's accuracy from 0.5mm to 0.18mm above.
The identification and repair of anomalous measurements in the measurement of big diameter based on rolling-wheel method
Haiou Chen, Xiaofen Yu
Rolling-wheel method is an effective way of measuring big diameter. After amending the temperature error and pressure error, the uncertainty of measurement can not be φ =5um/m stably because of the influence of skid. The traditional method of identifying skid loses sight of the influences of the unstable motor speed, the appearance form error and the eccentric of installation of the big axis and rolling wheel and so on, so the method has its limitation. In this paper, a new method of multiple identification and repair is introduced, namely n diameters are measured and Chauvenet standard is used for identifying the anomalous measurements one by one, and then the average value of the remaining data is used for repairing identified anomalous measurements, and the next round identification and repair is carried out until the accuracy requirement of the measurement is satisfied. The result of experiments indicates that the method can identify anomalous measurements whose offsets caused by the skid are greater than 0.2φ , and the uncertainty of measurement has improved substantially.
The differences between flatness and parallelism in shape-position tolerance
Flatness and parallelism which have relations and differences between them are two important subjects in shape-position tolerance theory. It is necessary to be discussed in detail through analysis, research, comparing and summarizing as they are widely used in industry whereas their concepts are easily be confused. This paper carries on the comparison based on the following aspects. (1) Definitions of tolerance zone. (2) Tolerance category, Marking methods and tolerance values. (3) Measuring methods. (4) Examples. For a object with given flatness and parallelism tolerance, the similarities and differences are analyzed and compared in the views of shape,size,direction and position etc. It would be useful references to personals in engineering, technology and other relevant fields.
The calculation of the reproducibility error in the technological system with the clamp on the gas power
Xingdong Shen, Gang Dong
The paper deduced a calculation formula by the classic control theory on the Reproducibility Error of parts processing in the technology system, the flexible clamp system , with the clamping device on the gas power, and analyzed its influencing factor with examples, the Reproducibility Error law: The larger the diameter of the cylinder, the smaller the error; the slower the tool speed, (k values smaller), the smaller the error.
Straightness error evaluation of additional constraints
Ling Pei, Shenghuai Wang, Yong Liu
A new generation of Dimensional and Geometrical Product Specifications (GPS) and Verification standard system is based on both the Mathematical structure and the Metrology. To determine the eligibility of the product should be adapt to modern digital measuring instruments. But in mathematizating measurement when the geometric tolerance specifications has additional constraints requirement, such as straightness with an additional constraint, required to qualify the additional form requirements of the feature within the tolerance zone. Knowing how to close the geometrical specification to the functional specification will result in the correctness of measurement results. Adopting the methodology to evaluate by analyzing various forms including the ideal features and the extracted features and their combinations in an additional form constraint of the straightness in tolerance zone had been found correctly acceptance decision for products. The results show that different combinations of the various forms had affected acceptance on the product qualification and the appropriate forms matching can meet the additional form requirements for product features.
The study on the sampling method of the helicoid surface
Yangkuan Guo, Lianqing Zhu, Qingpeng Chen
The sampling method is closely related to the measurement accuracy, the measurement efficiency, measurement results, error evaluation and many other factors. This paper presents a feasible method. The worm of typical entity were measured, at the same time, the measured data are processed. Helicoid surface of the worm is measured by using Coordinate Measuring Machine (CMM). The surface is measured by using two methods, one is spiral profile method, and another is tooth profile method. Comparing the parameters solved in the spiral method and tooth method is to determine the optimal sampling method.
Dynamic errors modeling of CMM based on generalized regression neural network
Weihong Zhong, Hongwei Guan, Yingdao Li, et al.
The development of modern manufacturing requires a higher speed and accuracy of coordinate measuring machines (CMM). The dynamic error is the main factor affecting the measurement accuracy at high-speed. The dynamic error modeling and estimation are the basis of dynamic error correcting. This paper applies generalize regression neural network (GRNN) to establish and estimate dynamic error model. Compared with BP neural network (BPNN), GRNN has less parameters, only one smoothing factor parameter should to be adjusted. So that it can predict the network faster and with greater computing advantage. The running speed of CMM axis is set through software. Let it running for the X axis motion. The values of the grating and the dual frequency laser interferometer are gained synchronously at the same measure point. The difference between the two values is the real-time dynamic measurement error. The 150 values are collected. The first 100 values of the error sequence are used as training data to establish GRNN model, and the next 50 values are used to test the estimation results. When the smooth factor is set at 0.5, the estimation of GRNN training data is better.The simulation with the experimental data shows that GRNN method obtains better error estimation accuracy and higher computing speed compared with BPNN. GRNN can be applied to dynamic error estimation of CMM under certain conditions.
Study on the accuracy factors of large-scale photogrammetry system
Jun Wang, Mingli Dong, Naiguang Lu
In photogrammetry system, the Base-Distance Ratio, the Image Scale, and the Image Standard Error, which construct the network strength of the system, are the main accuracy factors. In this paper, the normal and convergent network configurations of the photogrammetry are studied and the Network Strength, which presents the strength and accuracy of the camera station network, is expressed with the accuracy factors mentioned above. In order to verify the validation of this expression, the large-scale 3D reference field is designed and used to test the effects of these accuracy factors. The experimental results show that the relationship between the accuracy and the factors is consistent with the expression. These conclusions will guide the photogrammetric work to reduce the system errors.
Application of genetic algorithm in the evaluation of the profile error of archimedes helicoid surface
Lianqing Zhu, Yunfang Chen, Qingshan Chen, et al.
According to minimum zone condition, a method for evaluating the profile error of Archimedes helicoid surface based on Genetic Algorithm (GA) is proposed. The mathematic model of the surface is provided and the unknown parameters in the equation of surface are acquired through least square method. Principle of GA is explained. Then, the profile error of Archimedes Helicoid surface is obtained through GA optimization method. To validate the proposed method, the profile error of an Archimedes helicoid surface, Archimedes Cylindrical worm (ZA worm) surface, is evaluated. The results show that the proposed method is capable of correctly evaluating the profile error of Archimedes helicoid surface and satisfy the evaluation standard of the Minimum Zone Method. It can be applied to deal with the measured data of profile error of complex surface obtained by three coordinate measurement machines (CMM).
Multi-band pyrometer uncertainty analysis and improvement
Yongjun Yang, Xuecong Zhang, Jing Cai, et al.
According to the energy ratio value of multi-band radiating from the measured surface, the 'true' temperature can be calculated by multi-band pyrometer. Multi-band pyrometer has many advantages: it can hardly be affected by the emission of measured surface and the environment radiation, and it has higher Signal-to-Noise Ratio and higher temperature measurement accuracy. This paper introduces the principle of a multi-band pyrometer and the uncertainty of measurement result is evaluated by using Monte-Carlo Method (MCM). The result shows that the accuracy of effective wavelength is the largest source of uncertainty and the other main source is reference temperature. When using ordinary blackbody furnace with continuous temperature, which can provide reference temperature and calibrate effective wavelength, the uncertainty component is 2.17K and 2.48K respectively. The combined standard uncertainty is 3.30K. A new calibration method is introduced. The effective wavelength is calibrated by monochromator, and the reference temperature is provided by fixed point black body furnace. The uncertainty component is decreased to 0.73K and 0.12K respectively. The measurement uncertainty is decreased to 0.74K. The temperature measurement accuracy is enhanced.
Investigation on phase compensation method for measurement of resistance of quartz crystal
Yanlin Wang, Zhongyu Wang, Dong Li, et al.
Resistance is one of four basic parameters of quartz crystal, and the others can be deducted from it. However, its strict requirements on fabrication technology for π network, and the phase shift induced by tray reactance and quartz crystal static capacitance, the highest accuracy measurements of resistance is difficult to be realized. Here, active compensation to additional-phase offset induced by stray reactance in π network and quartz crystal static capacitance (C0) is presented, which facilitates measurement of resistance of quartz crystal, and reduces the requirements of fabrication technology for π network. The experimental result indicates that the measurement accuracy of resistance R1 in quartz crystal can be up to ±5% with this measurement system.
Universal geometric error modeling of the CNC machine tools based on the screw theory
Wenjie Tian, Baiyan He, Tian Huang
The methods to improve the precision of the CNC (Computerized Numerical Control) machine tools can be classified into two categories: error prevention and error compensation. Error prevention is to improve the precision via high accuracy in manufacturing and assembly. Error compensation is to analyze the source errors that affect on the machining error, to establish the error model and to reach the ideal position and orientation by modifying the trajectory in real time. Error modeling is the key to compensation, so the error modeling method is of great significance. Many researchers have focused on this topic, and proposed many methods, but we can hardly describe the 6-dimensional configuration error of the machine tools. In this paper, the universal geometric error model of CNC machine tools is obtained utilizing screw theory. The 6-dimensional error vector is expressed with a twist, and the error vector transforms between different frames with the adjoint transformation matrix. This model can describe the overall position and orientation errors of the tool relative to the workpiece entirely. It provides the mathematic model for compensation, and also provides a guideline in the manufacture, assembly and precision synthesis of the machine tools.
A method of rapped selection and calculating formed milling cutter
Hongping Yu, Yilong Gong
With center distance between machining and workpiece reduced, formed milling cutter in cutting edge after persistent cutting and grinding can lead to blunt, thereby spiral gear-shape error of cutter produces surface. When the precision of helicoids section shape of workpiece is lower, it can use ordinary, batch of milling cutter to cutting workpiece through the installation debugging in parameters, such as the center distance and axial intersection angle, etc, in order to reduce workpiece gear-shape error. This paper introduces a method of calculating parameters of the section workpiece helicoids of tooth head profile according to the shaft section milling cutter tooth shape. Through this method can rapidly determine the selected milling machining precision of tooth profile is whether or not within the allowed in the workpiece gearshape error range.
Photoelectric Measuring Technologies
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Optical 3D testing of micro structures
Optical measuring techniques for micro structures are limited by the numerical aperture of the objective. Within these limits different techniques can be used: white light interferometry uses an illumination source with short coherence length to determine the absolute position of the surface while confocal profilometry uses the principle of the defocus of light. As a relatively new technique, digital holography offers the simultaneous measurement of intensity and phase of a wave to generate a 3D image with the acquisition of just one single image. We give some application examples of these techniques to micro structures including deformation measurements.
CCD measuring system research for calibrators of headlamp tester for motor vehicle
Zhiping Nie, Tao Zhang, Jie Zhao
A measuring system for calibrators of headlamp tester for motor vehicle is introduced in the paper. It utilizes planar array Charge-coupled Device (CCD)as detector to digitalize the image of lighting area on the screen formed by the perpendicular irradiation of calibrator's lamp. By using computer digital image processing technology programmed with VC++, the system can measure the characteristic parameters automatically, such as luminous intensity, center of far light, corner of near light. The advantage is high accuracy, good repetition and automatic measurement.
The design of wavelength selector for full-automatic ELISA analyzer
Yan Bao, Mingli Dong, Lianqing Zhu, et al.
In recent years, ELISA technology has been developed rapidly and full-automatic ELISA analyzer, which is of significant practical value is widely used in the diagnosis of many diseases, such as, bacteria and viruses. Optical detection system is the hard core of fully automated ELISA analyzer and the key part of system is high-precision wavelength selector. The authors in this paper present the design of wavelength selector composed of light source, optical circuit plan, color filters and the module of signal acquisition. A control system for stepper motor which is used to choose the suitable color filters based on the microcontroller 8051 is introduced. From the results of experiment test, it can be seen that the wavelength selector is sufficient to meet the requirements of the full-automatic ELISA analyzer.
Design of liquid level measurement for sampling module of full-automatic enzyme immunoassay instrument
Hong Li, Lianqing Zhu, Haitao Chang, et al.
To support the need for the design of sampling module in the full-automatic enzyme immunoassay instrument, this paper completed the design and verification of liquid level detector based on capacitive sensor. Using the capacitance effect existing between the sample needle and the ground (the machine frame), we take the sample needle and the ground as the capacitor poles. By means of the RC oscillation circuit, we convert the change of capacitance to frequency for a measure, in order to achieve the level detection. The stepping motor controls the sample arm with the modular design, and C8051F330 is chosen as main control chip in this system. Through the experimental analysis, we proved the reliability of the detection of the sample level based on the capacitance liquid level detection principle. This study provided a theoretical basis to the level parameters of the full-automatic enzyme immunoassay instrument.
Color-encoded structured light for one-shot shape acquisition
Qimeng Tan, Naiguang Lu, Xiaoping Lou, et al.
A color-encoded structured light for one-shot shape acquisition is proposed in this paper. The colored horizontal stripes pattern is encoded based on a De Bruijn sequence of order 3 over 5 color symbols. The edges of stripes in the camera image can be located with sub-pixel accuracy by using both the hue and intensity components in HSI model. Subsequently, the detected edges of stripes and their corresponding projected stripes edges can be triangulated to reconstruct 3D shape of the object. Experimental results show that both accuracy and stability from HSI algorithm are much better than that from traditional RGB algorithm. The method which recovers 3D shape of the object based on one-shot can be applied to measure the moving object.
Grinding surface roughness measurement based on Gauss-Markov random field model of laser speckle pattern texture
Lei Yang, Rongsheng Lu, Liqiao Lei
The relationships between laser speckle pattern texture features of grinding surface and surface roughness are investigated. The laser speckle pattern texture images of surface roughness are taken by a simple setup. Gauss-Markov random field (GMRF) model is a kind of texture model method which can describe probability model of gather of texture and be able to capture the local contextual information in an image. Therefore, by modeling GMRF model the laser speckle texture images of grinding surface are analyzed. Feature vectors of GMRF are calculated with different neighbor sets. Texture features- Mean, Variance and Energy are extracted to characterize grinding surface roughness from GMRF feature vectors. The relationships curves are drawn between the texture features and surface roughness. The experiment results show that the surface roughness contained in the surface speckle pattern texture images has a good monotonic relationship with texture features of GMRF model. This method can extract the surface roughness of the object surface composed of the same material and machined by the same method as the standard specimen.
Multiview photogrammetry data registration by the way of stereovision movement tracking
Peng Sun, Naiguang Lu, Boen Wang, et al.
A point cloud registration method based on stereovision movement tracking is proposed in this paper. The movement tracking and analysis system is composed of a stereovision measurement system and target bars. Target bars are fixed on a structured light profile scanning system. Retro-reflect target points pasted on the bars are captured by the stereovision measurement system to compute location and orientation of the scanner. The scanner is controlled to move in the view field of the movement tracking system to complete a whole scan of the large scale object. Transformation parameters including the rotation matrixes and translation vectors between local scanning coordinate systems and the global movement tracking coordinate system are computed by tracking the retro-reflect target points. Then, local cloud data of each scan is transformed into the global tracking coordinate system which is obviously an easier registration method. Experimental system is built and experiments are carried out. A movement tracking experiment is designed to give a maximum error of movement tracking less than 0.3 millimeters. Registration algorithm is verified useful by another experiment which gives a complete profile scanning of a large scale fan blade work piece. Accuracy experiments are designed to result in an average registration error less than 0.3 millimeters and standard deviation less than 0.2 millimeters.
Research on chromatic confocal technology for displacement measurement
Wenyi Deng, Chunhui Niu, Naiguang Lv, et al.
The chromatic confocal method for displacement measurement is described in the paper. Some factors that affect measuring precision and measuring range are discussed, which include diameter of detector pinhole, spectrum width of light source, the chromatic dispersion of lens, the resolution of spectrum analyzer, data processing method, etc. The objective lenses with different chromatic dispersion using in the experiment system are designed and manufactured. The method processing spectrum line received from spectrometer is studied and corresponding program is compiled. The experiment system is composed of a light resource with continuum spectrum, an object lens (a multi-lens optical system), two pinholes, a beam splitter and a spectrum analyzer. The experimental systems with different lenses (different chromatic aberration) are calibrated separately to determine the relationship between the received wavelength and corresponding distance to target surface.
Fiber Bragg grating based sensor for measuring temperature of in vivo lesion
Xianhui Mao, Chunhui Niu, Yong Lu
Because of the heat-resistant difference between the cancer cell and the normal cell, the normal cell can resistant higher temperature than cancer cell does. Clinical experiments showed that microwave or ultrasonic can effectively cure cancer. But since there is strong electromagnetic interference, the conventional temperature sensor will find itself hard to get the accurate temperature. So it is necessary to find a feasible sensor to measure the temperature. Fiber optic grating (FBG) sensor is excellent candidate for measuring temperature of in vivo lesion. In this paper, the investigation on the application of an optical fiber sensor in the field of biomedical engineering was introduced. The main objective of our investigation has been to develop a novel senor based on FBG to measure the temperature of in vivo lesion. Based on the Bragg equation, the temperature sensing properties of fiber optic grating was studied and the affection of central wavelength on the FBG sensing sensitivities have also been analyzed. In order to reduce the error of the FBG sensors system, it is necessary to adopt a good demodulation algorithm to calculate peak wavelength. An experimental system was set up which to test feasibility of the sensor. Among some of the peak detection algorithms, tested by experimental measuring system, the peak detection method by the Gaussian nonlinear curve fitting was finally adopted and the test results showed that the temperature measuring system based on the FBG was in the accuracy of 0.1°C.
Cruor measurement system based on photometry
Lianqing Zhu, Zicai Wang, Ningning Dong, et al.
This paper presents the basic principle and design method of the cruor measurement system with photometry. Meanwhile the hardware structure and data processing method of the system are also presented. The selection of different monochromatic lights increases the specificity of the tests. The Percentage Detection Method reduces the impacts of the special samples on the results. The effect of stray light is eliminated by taking two fairly close measurements of the transmitted light during the absorbance measurement. Thereby the tests can be more accurate.
Scanning Twyman interferometer for measuring small angular displacement
Jianguo Ma, Yue Tong
We present a simple but effective method for measuring small angular displacement based on a scanning Twyman interferometer ,in which, one of the two mirrors is mounted on the piezoelectric ceramic (PZT) droved by saw-tooth voltage, the status of interference fringes changes from static to dynamic. A photoelectric detector detects this dynamic photo-signal and changes into electronic signal. The signal is inputted into an oscillograph. The oscillogram will present interference crests. The method for measuring small angular displacement is based on the linear relation between the angular displacement and the crest shift on the oscillogram.
Research on all fiber beat length measurement system for polarization-maintaining fibers
Li Peng, Lishuang Feng, Xiaoqing Zhang, et al.
Polarization-maintaining fiber (PMF) has attracted great attentions not only due to its ability to realize coherent optic communication with ultrahigh-capacity, but also because it can be widely employed in high-precise fiber-optic sensors and optic information processors, e.g., fiber-optic gyroscope and fiber-optic amperemeter. Distinct with common monomode optic fibers, additional birefringence is introduced in the PMF, minimizing the effect of mode coupling between two orthogonal polarization modes in optic fibers. Thus, light polarization can be maintained after long distance transmission in the PMF. However, beat-length, which reflects the characteristic of induced birefringence and evaluates the ability of polarization maintaining, is one of the most important parameters for PMF. Accurate measurement of PMF beat length becomes more and more important along with the expanding of its application field. The uniqueness of the measurement results determines the identity of PMF fabrication and the resolution of fiber-optic sensors. The existing measurement methods for PMF beat length are introduced first. Most testing setups are established by several individual components, which lead to complicated setup, inconvenient testing, and unsteady measurement. In this paper, a novel all fiber beat length measurement system is presented, where optic source, integrated optic modulator, stress apply structure, polarization detector, and polarization indicator of output light are included. The configuration and working principle of the whole system, and the designing and realization of each components, are addressed in the paper. Furthermore, the influence on measurement results by the relative direction between applied stress and principal axis of the optic fiber is analyzed. Moreover, optimized designs, including polarized light incidence, pressure apply, and precise movement systems, are performed, which ensure the identical pressure apply direction in the moving process. Finally, measurement of PMF samples is carried out on experimental setup. In comparison with the other existing system, due to its all fiber light incidence structure, the novel beat length measurement system represents great stability and high reliability.
Heterodyne multi-frequency method for 3D profile measurement
Xiaoping Lou, Naiguang Lv, Peng Sun, et al.
A binocular structured light measurement system using heterodyne multi-frequency method is researched in this paper. Three steps must be done to recover 3D profile information: cameras calibration; points matching; 3D information reconstruction. The intrinsic and extrinsic parameters of cameras are calibrated by Zhengyou Zhan's method [1]. Stereo vision model is the basic rule of 3D recovering. Techniques of phase shift and heterodyne multi-frequency are used to aid points matching. Some coded digital fringes are projected to the free-form surfaces and corresponding images are captured by two cameras simultaneously. The wrapped phase map is obtained through four-step phase shift. In a single cycle, phase value is calculated using arctangent function and it is between -π and π. The heterodyne multi-frequency method is applied to get the absolute phase map. When the number of frequencies is changed from 2 to 3, or 4, the unwrapping accuracy and matching results are improved. The processing theory and experimental results are illustrated and analyzed. The experimental results show that accurate and reliable phase result can be obtained on phase map boundaries and break points, which proves its feasibility in industrial situations.
Concentrating performance analysis for large dish solar concentrator
Qiao Xu, Qiancheng Zhao, Yejun Qin, et al.
Large dish solar concentrator is consist of many small parabolic mirrors. In the processing and installation, small mirror will deviate from the ideal state, meanwhile some errors including non-parallelism of solar rays, tracking error etc will affect the performance of the concentrator. Based on the rotation parabolic's condenser characteristics and some previous literature's ideas. we take one part of the large dish to analysis the size of focal spot which is affected by non-parallelism of solar rays, ray tracing error, and the shift of the receiving surface position these three factors. Then, through a series of numerical simulations, we can get the analysis results which present a reference for the dish solar concentrator design and installation.
Surface roughness measurement for semi-spherical workpieces based on Bessel structured beam
Hao Meng, Lianqing Zhu, Zhongyu Wang
Laser triangulation method is a method in common use to measure surface roughness. In the traditional laser triangulation method, a Gaussian beam is used to scan the measured surface point by point. Since the data is collecting by means of point scanning, a considerable number of measurements are essential for the whole measured surface. Hence the measurement of a semi-spherical surface is costly and time consuming. In this paper Bessel structured beam is used in the triangulation measurement system instead of Gaussian beam. Owing to the characteristics of its longer focal depth, the system using Bessel structured beam possesses the advantages of wider measurement range, higher theoretical measurement accuracy and resolution over the traditional laser triangulation measurement system. With scanning the measured surface using the concentric rings of Bessel structured beam, a piece of area on the workpieces' surface can be measured through only once measurement. Taking a latitudinal circle with a radius of 5mm as an example, it takes only 9.3s to obtain the surface profiles of the whole latitudinal circle with the proposed system in this paper, while it must be measured point by point with the stylus device and more than 60s are needed.
Nonlinear effects in fiber optic interferometers for propagation in optical fiber low-power single-frequency infrared radiation of a semiconductor laser
A. L. Dmitriev, S. A. Bulgakova
Fiber-optic interferometers are one of the most sensitive components of optical meters of physical fields, mechanical strains and movements. The greatest efficiency is shown when such devices are used together with semiconductor sources - lasers, LED and SRD. Until very recently nonlinear effects in optical instruments and devices were thought to play an obvious role only with emissions having comparatively great power (from some units up to some tens mW ) in quartz fibers. The results of the most recent researches show that non-linear effects in fiber-interferometers with the length of baselines up to some kilometers with small emission power in the fiber (deciles mW ) play an important role.
A novel amblyopia treatment system based on LED light source
Xiaoqing Zhang, Qingshan Chen, Xiaoling Wang
A novel LED (light emitting diode) light source of five different colors (white, red, green, blue and yellow) is adopted instead of conventional incandescent lamps for an amblyopia treatment system and seven training methods for rectifying amblyopia are incorporated so as for achieving an integrated therapy. The LED light source is designed to provide uniform illumination, adjustable light intensity and alterable colors. Experimental tests indicate that the LED light source operates steadily and fulfills the technical demand of amblyopia treatment.
Signal Analysis and Image Processing
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A novel digital shearography with wide angle of view for nondestructive inspection
Sijin Wu, Lianxiang Yang
Digital shearography is widely accepted in non-destructive inspection of honeycomb sandwich structures due to its advantages of validity, non-contact, simple setup and robustness. In digital shearography, Michelson shear interferometer (MSI) is a dominant shearing device because it is easy to change the shearing amount and direction. However, the conventional digital shearography based on MSI suffers from the small angle of view which limits its employments in full field inspection of a big size sample at a short working distance. A novel structure digital shearography with wide angle of view introduced in this paper is developed to overcome the disadvantage. In the new shearography optical arrangement, the image lens is separated with the camera and locates at the front of system. A 4f imaging system is used to transmit the image of object from the imaging lens to the camera. The shearing device, MSI, locates between the imaging lens and camera. The angle of view in this shearography has no limit to the setup but it is based on several parameters, such as the focus length of the imaging lens and the size of the imaging device inside the camera. Thus wide angle of view can be easily achieved by changing those parameters. Using this novel digital shearography, full field inspection of the big size honeycomb sandwich structure can be rapidly conducted at a short working distance.
Recent developments and applications for optical full field strain measurement using ESPI and DIC
Thorsten Siebert, Hans-Reinhard Schubach, Karsten Splitthof
Optical measurement techniques for full-field analysis of deformation, strain and vibration are commonly used in various fields of mechanical engineering. The focus of this presentation is on the recent developments and applications of the Electronic Speckle Pattern Interferometry (ESPI) and Digital Image Correlation (DIC) technique. The full-field function allows an easy understanding of processes and designs under various conditions and their optimizations. We present a brief overview about recent applications of ESPI for the determination of static strain in composite and inhomogeneous materials and the use of the technique for optimization of the design of components in automotive applications. DIC techniques have proven to be a flexible and useful tool for deformation analysis. Modern algorithm and computer allows the calculation of the full-field three-dimensional displacement and strain in real-time. This information can be converted to an electronic analog signal and be used for the real-time monitoring of the test. Using High Speed cameras the DIC technique can be applied to vibration problems and a high resolution in the temporal domain can be achieved. Different types of loading, like harmonic, shock or noise excitation, are applicable.
Laser spot size of real-time detection and control system for laser polishing
Feng Lie Zhang, Xing Fu, Qian Lin
During laser micro-machining, the constant control of laser energy density is a key technology to improve the processing precision. This paper presents a laser spot size of real-time detection and control system design on the base CCD and FPGA processing technology. Using CCD video signal binarization method and FPGA processing technology, we realized real time detection and control of spot area on the workpiece to achieve a constant purpose. The relative measurement error of spot size is very small as maximum 0.5 percent, the resolution of spot size measurement is less than 10μm2. This system can be directly applied to control of laser spot in laser micro-polishing.
Study on adaptive thresholding technique of image denoising based on wavelet transform
Xi'an Zhu, Xiao Xie
It is studied in the paper that an adaptive soft and hard thresholding image denoising method, in which image pyramid decomposing is realized by wavelet transform, and the mean value, mid-value and root mean square value of different sub bands are calculated as thresholding. The image is added into different kinds and different intensities noise, and processed by different wavelet decomposing levels and thresholding selected algorithms, the total 27 kinds of thresholding combination schemes are completed in the research process. The SNR (signal noise ratio) and PSNR (peak signal noise ratio) of denoised image are compared and analyzed and benefited results are achieved. Furthermore, the algorithm in reference is realized by MATLAB program, the results of reference are compared with that of the paper to demonstrate the significance and correctness of the results in the paper.
A novel method for field complete parameters calibration of stereo vision sensor
Bin Wu, Qingze Gao, Hongyan Zhu
To meet the need of high precision vision measurement, a novel method for field complete parameters calibration of stereo vision sensor is presented based on the two-dimensional target with unknown motion. Method: Firstly, according to the perspective projection model of camera and its coordination's relationship, the measurement math model is set up for stereo vision sensor. Secondly, the precision parameters of camera are calibrated with Zhang's camera calibration method based on planar target and the initial transition matrix of stereo vision sensor can be got. Finally, with the 3D measurement math model of stereo vision sensor and Levenberg-Marquardt method, the optimized parameters of stereo vision sensor are achieved. Result: Based on the above calibration method and two-dimensional target with unknown motion, the complete parameters of stereo vision sensor (including the camera's parameters and the transition matrix between two cameras) are calibrated. Experiments show that the relative error of distance measurement is less than 1.6% using a calibrated stereo vision sensor. Conclusion: The method is simple and convenient, with better efficiency, lower labour intensity and higher precision.
Displacement sensor with controlled measuring force and its error analysis and precision verification
Liangen Yang, Xuanze Wang, Wei Lv
A displacement sensor with controlled measuring force and its error analysis and precision verification are discussed in this paper. The displacement sensor consists of an electric induction transducer with high resolution and a voice coil motor (VCM). The measuring principles, structure, method enlarging measuring range, signal process of the sensor are discussed. The main error sources such as parallelism error and incline of framework by unequal length of leaf springs, rigidity of measuring rods, shape error of stylus, friction between iron core and other parts, damping of leaf springs, variation of voltage, linearity of induction transducer, resolution and stability are analyzed. A measuring system for surface topography with large measuring range is constructed based on the displacement sensor and 2D moving platform. Measuring precision and stability of the measuring system is verified. Measuring force of the sensor in measurement process of surface topography can be controlled at μN level and hardly changes. It has been used in measurement of bearing ball, bullet mark, etc. It has measuring range up to 2mm and precision of nm level.
Small sample analysis of a platform vibration via bootstrap method
Zhongyu Wang, Jianyong Sun, Jianjun Zhang, et al.
The data obtained by the vibration platform could hardly have a big sample size and a typical probability distribution. To overcome this problem, the authors in this paper present a new statistical induction method of bootstrap sampling under the vibration environment of the airborne platform. The bootstrap method is used to imitate distribution of some systems by resample operation in the case of unknown probability with small sample. This method is also applied in the data analysis for a platform vibration environment. The calculation results indicate this method with a high reliability at a given confidence level by the experiment.
Temperature prediction and analysis based on BP and Elman neural network for cement rotary kiln
Baosheng Yang, Xiushui Ma
In order to reduce energy consumption and improve the stability of cement burning system production, it is necessary to conduct in-depth analysis of the cement burning system, control the operation state and law of the system. In view of the rotary kiln consumes most of the fuel, we establish the simulation model of the cement kiln used to find effective control methods. It is difficult to construct mathematical model for the rotary cement kiln as the complex parameters, so we expressed directly using neural network method to establish the simulation model for the kiln. Choosing reasonable state and control variables and collecting actual operation data to train neural network weights. We first in-depth analyze mechanism and working parameters correlation to determine factors of the yield and quality as the model input variables; then constructed cement kiln model based on BP and Elman network, both achieved good fitting results. Elman network model has a faster convergence speed, high precision and good generalization ability. So the Elman network based model can be used as simulation model of the cement rotary kiln for exploring new control method.
Analysis and simulation research of electromagnetic field model in resistance spot welding
Wenbo Xuan, Zhen Luo, Yang Li, et al.
Resistance spot welding (RSW) has rarely been applied to the fields requiring high welding quality, as it is limited by the instability of welding quality and quality monitoring system. Inversion imaging of nugget is a new developing method of monitoring welding quality at this background. Before the inversion image, this paper does some researches on the electromagnetic forward problem by establishing the forward model and simulating its electromagnetic field. In order to verify the reliability of this model, this paper takes the magnetic field signals as example to carry out the spot welding experiments. By comparison, the data illustrates that this electromagnetic model is reliable within a certain distance range. Besides these, this paper also does some researches on the different patterns of Hall sensor array, in order to find the array pattern with smaller errors to carry out inversion imaging.
Modeling study of the ABS relay valve
Ming Lei, Min Lin, Bin Guo, et al.
The ABS (anti-lock braking system) relay valve is the key component of anti-lock braking system in most commercial vehicles such as trucks, tractor-trailers, etc. In this paper, structure of ABS relay valve and its work theory were analyzed. Then a mathematical model of ABS relay valve, which was investigated by dividing into electronic part, magnetic part, pneumatic part and mechanical part, was set up. The displacement of spools and the response of pressure increasing, holding, releasing of ABS relay valve were simulated and analyzed under conditions of control pressure 500 KPa, braking pressure 600 KPa, atmospheric pressure 100 KPa and air temperature 310 K. Thisarticle provides reliable theory for improving the performance and efficiency of anti-lock braking system of vehicles.
A new fault detection method of conveyer belt based on machine vision
Bingxia Shen, Muyan Ma
A new fault detection and measurement method of conveyer belt based on machine vision is proposed. The conveyer belt used in coal mine transportation usually goes two kinds of faults: joint's elongation and local rust. Under this engineering background, the system focuses on detecting the state of conveyer belt and measuring the fault size. This paper brings forward a modified BP neural network to detect and classify different faults. The new BP algorithm's detecting speed is rapid, and the correct recognition rate of the joint and erosion has a great improvement. The measurements of joint's length and erosion's area are realized on the machine vision platform which built by LabVIEW IMAQ Vision module. And the measurements have a high accuracy. The results demonstrate that the new method is effective and efficiency.
Modified signal processing method for spot welding monitor system
Rui Wang, Zhen Luo, Yang Li, et al.
The method for resistance spot welding quality detection is becoming a serious problem recently. Aluminum alloy has high-conductivity and good thermal conductivity, which affects the stability of welding quality. In this paper, a spot welding monitor system based on magnetic sensor array technique is designed for welding quality detection. And a new signal processing method called the "W-ICA" algorithm is proposed to separate the object signals. The results show that the spot welding monitor system works well. And the modified W-ICA algorithm can extract the mixing signal validly and provide us the original signal information. The extract results of the magnetic sensor array help us to analysis whether the spot quality is good or bad.
Impedance measurement of quartz crystal based on network analysis method
Guili Liu, Zhengjie Dong, Dong Li, et al.
A method for the determination of impedance of quartz crystal using automatic network analyzer electrical techniques is introduced in this paper. The vector network analyzer ENA 5070B which is produced by Agilent Company is taken to measure S parameters in short-circuit, open-circuit and crystal-circuit. The algorithm recommended in international standard IEC444-5 is based on theory of two-port S parameter transmission method and relationships between transmission admittance (Y21) and scattering parameters(S parameters). By data analysis, circuit symmetry is good. And around the resonance frequency, amplitude and phase of S parameters have obvious display the crystal characteristics. The phase is not zero on the resonance frequency because of lead inductance and parasitic capacity. The amplitude/phase-frequency curve of crystal impedance, which is in conformity with the stimulation of the crystal model, is achieved. By de-embedding process, high accuracy of series resonant frequency and the impedance around it are measured. Results have created favorable conditions for precisely determining the values of the electrical parameters of quartz crystal units.
Distributed edge detection algorithm based on wavelet transform for wireless video sensor network
Qiulin Li, Qun Hao, Yong Song, et al.
Edge detection algorithms are critical to image processing and computer vision. Traditional edge detection algorithms are not suitable for wireless video sensor network (WVSN) in which the nodes are with in limited calculation capability and resources. In this paper, a distributed edge detection algorithm based on wavelet transform designed for WVSN is proposed. Wavelet transform decompose the image into several parts, then the parts are assigned to different nodes through wireless network separately. Each node performs sub-image edge detecting algorithm correspondingly, all the results are sent to sink node, Fusing and Synthesis which include image binary and edge connect are executed in it. And finally output the edge image. Lifting scheme and parallel distributed algorithm are adopted to improve the efficiency, simultaneously, decrease the computational complexity. Experimental results show that this method could achieve higher efficiency and better result.
A fast target location method for the photogrammetry system
Jun Wang, Mingli Dong, Bo Liang
In close range photogrammetry and vision metrology, several images which are taken at different stations are required for high accuracy. Before camera calibration and 3D reconstruction, the targets in the images must be recognized and located with high accuracy firstly. Furthermore, in order to monitor the deformation of the surface, real-time and on-line photogrammetry system is needed, in which high speed is necessary. So, the image processing method and speed will affect the accuracy and speed of the photogrammetry system. This paper describes a fast target location method for the photogrammetry system. Experimental results show that the target edge pixels preserve the important geometric information for subpixel centroid, which can reach accuracies to 2-3% of the pixel size. The process time of an image with 3008x2000 pixels is about 0.1S, much higher than other similar methods.
The digital compensation technology system for automotive pressure sensor
Bin Guo, Quanling Li, Yi Lu, et al.
Piezoresistive pressure sensor be made of semiconductor silicon based on Piezoresistive phenomenon, has many characteristics. But since the temperature effect of semiconductor, the performance of silicon sensor is also changed by temperature, and the pressure sensor without temperature drift can not be produced at present. This paper briefly describe the principles of sensors, the function of pressure sensor and the various types of compensation method, design the detailed digital compensation program for automotive pressure sensor. Simulation-Digital mixed signal conditioning is used in this dissertation, adopt signal conditioning chip MAX1452. AVR singlechip ATMEGA128 and other apparatus; fulfill the design of digital pressure sensor hardware circuit and singlechip hardware circuit; simultaneously design the singlechip software; Digital pressure sensor hardware circuit is used to implementing the correction and compensation of sensor; singlechip hardware circuit is used to implementing to controll the correction and compensation of pressure sensor; singlechip software is used to implementing to fulfill compensation arithmetic. In the end, it implement to measure the output of sensor, and contrast to the data of non-compensation, the outcome indicates that the compensation precision of compensated sensor output is obviously better than non-compensation sensor, not only improving the compensation precision but also increasing the stabilization of pressure sensor.
Micro-displacement measurement based on electronic speckle
Xiaoping Lang, Xiaoying Li
The method to measure micro-displacement based on Electronic Speckle is theoretically analyzed. An interferometer system is set up for measuring in-plane displacement of the measured surface, where the charge-coupled device (CCD) is used for image acquisition. It is well known that there are strong grain-shape random noises in the speckle patterns, which make heavy influence on the visibility and resolution of speckle fringes. Hence the technique of image processing is important to improve the contrast of the speckle fringes. For this reason, good experimental conditions are required to capture better speckle patterns; then image filtering and Fourier transformation are used to process the patterns. It is proved that the method in this paper can effectively improve the measurement results.
Research of vision measurement system of the instruction sheet caliper rack
Yu Liu, Ming Kong, Ying-jun Dong
This article proposes a method of rack measurement based on computer vision. It establishes a computer vision measurement system; the system consists of precision linear guide, camera, computer and other several parts. The entire system can be divided into displacement platform design system and image acquisition system two parts. The displacement platform system is that the linear guide campaigns driven by the driver controlled by the computer, to expand the scope of this measure realizing the measurement for the whole tooth. Image acquisition system is the use of computer vision technology to analysis and identification the capture images, the light source emitting light to the caliper rack, camerawork is to be the image which acquisitioned. Then input the images to the computer through the USB interface in order to the image analysis, such as Edge Detection, Feature Extraction and so on. And the detection accuracy reaches to sub-pixel level. Experiment with the rack modulus of 0.19894 instruction sheet calipers to measure, using image processing technology to realize the edge detection, and getting the edge of rack. Finally get the basic parameters of the rack such as p and s, and calculated individual circular pitch deviation fpt, total cumulative pitch deviation Fp, tooth thickness deviation fsn. Then comparison the measurement results with the Accretech S1910DX3. It turned out that the accuracy of this method can meet the requirements for the measurement of such rack. And the measurement method is simple and practical, providing technical support for the rack online testing.
Passive digital image authentication algorithm based on Tchebichef moment invariants
Mei Li, Zongyun Gu, Junling Kan
This paper presents a new passive image authenticate algorithm to check and measure the forged pictures and images in the regional copies and sticks. After reducing the image dimension by DWT (Discrete Wavelet Transform), the Tchebichef moment invariants is applied to the fixed sized overlapping blocks of a low-frequency image in the wavelet sub-band, and the eigenvectors are lexicographically sorted. Then, similar eigenvectors are matched by a certain threshold. Finally, the forgery part is identified by the threshold analysis. The experimental results show that proposed method can not only localize the copy forgery regions accurately, but also undergone some attacks like random noise contamination, lossy JPEG(Joint Photographic Experts Group) compression, rotation transformation etc. and reduce the amount of computation and improve the detection efficiency.
Micro- and Nanoprocessing and Measurement
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Contact pressure distribution of chemical mechanical polishing based on bionic polishing pad
Jun Wang, Xue-Ling Xing, Yu-Shan Lu, et al.
In order to improve the uniformity of the contact pressure distribution of chemical mechanical polishing, based on the Winkler foundation principle of mechanics and phyllotaxis theory of biology, a kind of stannum fixed abrasive pad with bionic surface texture has been designed, and the contact mechanism and ANSYS model have been established. By the calculating and analysis of contact pressure distribution on polishing wafer, the contact pressure distribution and the effects of the geometrical and physical parameters polishing pad on the contact pressure distributions have been obtained. The results show that the horizontal effect of the polishing pad is very small, the uniformity of contact pressure distribution can be improved, and there are the phyllotactic parameters which make the contact pressure distribution more uniformity.
Analysis of the polishing slurry flow of chemical mechanical polishing by polishing pad with phyllotactic pattern
Yushan Lv, Tian Zhang, Jun Wang, et al.
In order to make the polishing slurry distribution more uniform over the polishing region, a new kind of polishing pad, which has sunflower seed pattern, has been designed based on the phyllotaxis theory of biology, and the boundary conditions of polishing slurry flow have been established. By the help of computational fluid dynamics software (FLUENT), the flow state of the polishing slurry is simulated and the effects of the phyllotactic parameters of polishing pad on the flow field of polishing slurry are analyzed. The results show that when the polishing slurry is imported from the center of phyllotaxis polishing pad, the slurry flows along the counterclockwise and clockwise spiral grooves of phyllotatic pattern, which make fluid flow divergence around, and the flow field becomes more uniform.
Array servo scanning micro EDM of 3D micro cavities
Hao Tong, Yong Li, Futing Yi
Micro electro discharge machining (Micro EDM) is a non-traditional processing technology with the special advantages of low set-up cost and few cutting force in machining any conductive materials regardless of their hardness. As well known, die-sinking EDM is unsuitable for machining the complex 3D micro cavity less than 1mm due to the high-priced fabrication of 3D microelectrode itself and its serous wear during EDM process. In our former study, a servo scanning 3D micro-EDM (3D SSMEDM) method was put forward, and our experiments showed it was available to fabricate complex 3D micro-cavities. In this study, in order to improve machining efficiency and consistency accuracy for array 3D micro-cavities, an array-servo-scanning 3D micro EDM (3D ASSMEDM) method is presented considering the complementary advantages of the 3D SSMEDM and the array micro electrodes with simple cross-section. During 3D ASSMEDM process, the array cavities designed by CAD / CAM system can be batch-manufactured by servo scanning layer by layer using array-rod-like micro tool electrodes, and the axial wear of the array electrodes is compensated in real time by keeping discharge gap. To verify the effectiveness of the 3D ASSMEDM, the array-triangle-micro cavities (side length 630 μm) are batch-manufactured on P-doped silicon by applying the array-micro-electrodes with square-cross-section fabricated by LIGA process. Our exploratory experiment shows that the 3D ASSMEDM provides a feasible approach for the batch-manufacture of 3D array-micro-cavities of conductive materials.
Development of the precision long-stroke 3-DOF nano-stage for the photonic crystal process
Wen-Yuh Jywe, Chien-Hung Liu, Bor-Jeng Lin, et al.
In this paper, it develops a precision long-stroke 3-DOF nano-stage for the nano photonic crystal process. It integrates a linear motor driven long-stroke stage, a piezoelectric driven three-degrees-of-freedom (3-DOF) nano stage, multi-degrees-of-freedom (MDOF) laser interferometer measurement system and their control systems. The long-stroke nano-stage is a hybrid precision stage that can provide long-stroke and high precision positioning. The common focus horizon regulation system is used to keep the parallelism between writing instrument and the target while the laser direct writing instrument is used to write the nano structure needed. Furthermore, the automatic focusing and horizon control system can compensate the defocusing and angular errors that caused by machining automatically. With this precision 3-DOF nano-stage, the laser direct writing system can improve the process speed, overcome the optical limit of interference to reduce the writing spot, generate arbitrary patterns.
Design and application research of implantable wireless power transmission micro electro mechanical system
Longbin Liu, Xiaotao Shao, Fan Wu, et al.
With the rapid development of medical technology currently, the types of medical micro system which can be embedded to human body and satisfied with different purposes of treatment and diagnosis are in increasing numbers, and how to provide long-term, stable and effective electric energy is a key problem. The research illustrates the design and realization of Micro Electro Mechanical System (MEMS) planar inductor; method of design and manufacture of planar and circular spiral inductor of printed board with high quality factor is introduced; a set of MEMS which is suitable for implantable wireless power transmission is developed in order to realize the conversion from magnetic energy to electric energy. With theoretical analysis and experimental data, the scheme is confirmed to be suitable for the wireless power transmission to the implantable micro parts, which provides important reference value for the research of implantable wireless power transmission in the future.
Research on MEMS sensor in hydraulic system flow detection
Hongpeng Zhang, Yindong Zhang, Dong Liu, et al.
With the development of mechatronics technology and fault diagnosis theory, people regard flow information much more than before. Cheap, fast and accurate flow sensors are urgently needed by hydraulic industry. So MEMS sensor, which is small, low cost, well performed and easy to integrate, will surely play an important role in this field. Based on the new method of flow measurement which was put forward by our research group, this paper completed the measurement of flow rate in hydraulic system by setting up the mathematical model, using numerical simulation method and doing physical experiment. Based on viscous fluid flow equations we deduced differential pressure-velocity model of this new sensor and did optimization on parameters. Then, we designed and manufactured the throttle and studied the velocity and pressure field inside the sensor by FLUENT. Also in simulation we get the differential pressure-velocity curve .The model machine was simulated too to direct experiment. In the static experiments we calibrated the MEMS sensing element and built some sample sensors. Then in a hydraulic testing system we compared the sensor signal with a turbine meter. It presented good linearity and could meet general hydraulic system use. Based on the CFD curves, we analyzed the error reasons and made some suggestion to improve. In the dynamic test, we confirmed this sensor can realize high frequency flow detection by a 7 piston-pump.
Automatic Measurement and Control Technologies
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Optimized design of PSA nitrogen-manufacturing system based on PLC
Zongyao Nie, Xiushui Ma
Firstly introducing principle and technological process of PSA nitrogen-manufacturing system, on condition of its high air consumption and weak in nitrogen-manufacturing system at present. We repeatedly studied the controlled object in this process, analyzed the PLC procedure based on the program rule of PLC of Siemens S7-200 series, then re-program PLC procedure without altering the nitrogen production technique of PSA nitrogen-manufacturing system. At the same time, in order to improve the operation efficiency of the response of action, we also did experiment and demonstration in the consistency of the I/O port and peripheral equipment. In this paper, through optimization of hardware and software design, the nitrogen producing cost was calculated at RMB 0.35 per m3, declined by 12% from the original RMB 0.4 per m3.
Modeling and simulation of control system for 3-phase variable-reluctance stepper motor
Lihua Liu, Hong Li
In this paper, firstly, we establish the mode of the VR stepper motor on open-loop system of the stepper motor. Secondly, we control the exciting model, realize simulation of the circuit of unipolar driver and chop constant current control. Finally, we analyze the simulation results. And the results shows that these control methods can be applied to the actual motion of the system, which can improve the characteristics of the motion system of the stepper motor.
Design of the data processing system for parallel dual-joint coordinate measuring machine
Tao Wang, Lian-dong Yu
This paper introduces a data processing system for the three-dimensional information of double parallel-joint coordinate measuring machine (PD-CMM).The intelligent sensor units, which consisted of angle sensors, temperature sensors, microcontroller, are set in each joint and arm. The data are mainly the grating's output signal of each joint and the temperature change of each arm. The system samples and processes the data, then communicates with the host computer through USB interface. The simulation and experiments show that the data processing system works well.
Tooth surface modeling and measurement evaluation for spiral bevel gear based on gear measuring center
Peng Wan, Junjie Guo, Peilin Wu, et al.
In this paper, the mathematical modeling of spiral bevel gear is built using gear meshing theory, differential geometry theory and principle of virtual conjugate base surface, and software package is also developed accordingly. The mesh point coordinates of convex and concave surfaces of spiral bevel gear are determined by the parameters of machine tool adjustment, gear cutter and spiral bevel gear, the strategies of measurement control and the corresponding solving algorithm are determined accordingly. 3D scanning probe system is calibrated using a new method. With 3D scanning probe system, the scanning path of tooth surface is planned. The method of following-motion continuous scanning of tooth surface is proposed based on constant force measurement through parametric spline surfaces and the corresponding fitting algorithm. In virtue of this method, the offsets of 3D scanning probe in three directions are controlled through the interpolation points generated by measurement data, which can avoid interruption in the scanning process and the problem of probe accidental collision. The practicability and effectiveness of the above proposed methods, which lays a foundation for measuring spiral bevel gear highly effectivity and highly precision.
Research and design of automatic coal feeding control system in inclined shaft
Xiuli Wang, Qiaoe Zhao, Jinxi Wang
As the mechanized coal technology and productivity continues to increase sharply, the original coal belt conveyor system loading capacity has become a constraint to intensive production of the main bottlenecks of mining. In order to meet the needs of modern production, it is necessary for the original coal feeding system to optimize the design. This paper shows the design of electrical control ideas, that is mainly using a variable frequency control method. This new model described here has improved the typical system and has been reformed to allow it to enhance capacity. Safety has been greatly improved, and the failure rate is significantly reduced.
Echo state network prediction method and its application in flue gas turbine condition prediction
Shaohong Wang, Tao Chen, Xiaoli Xu
On the background of the complex production process of fluid catalytic cracking energy recovery system in large-scale petrochemical refineries, this paper introduced an improved echo state network (ESN) model prediction method which is used to address the condition trend prediction problem of the key power equipment--flue gas turbine. Singular value decomposition method was used to obtain the ESN output weight. Through selecting the appropriate parameters and discarding small singular value, this method overcame the defective solution problem in the prediction by using the linear regression algorithm, improved the prediction performance of echo state network, and gave the network prediction process. In order to solve the problem of noise contained in production data, the translation-invariant wavelet transform analysis method is combined to denoise the noisy time series before prediction. Condition trend prediction results show the effectiveness of the proposed method.
Implementation of remote monitoring and managing switches
Junmin Leng, Guo Fu
In order to strengthen the safety performance of the network and provide the big convenience and efficiency for the operator and the manager, the system of remote monitoring and managing switches has been designed and achieved using the advanced network technology and present network resources. The fast speed Internet Protocol Cameras (FS IP Camera) is selected, which has 32-bit RSIC embedded processor and can support a number of protocols. An Optimal image compress algorithm Motion-JPEG is adopted so that high resolution images can be transmitted by narrow network bandwidth. The architecture of the whole monitoring and managing system is designed and implemented according to the current infrastructure of the network and switches. The control and administrative software is projected. The dynamical webpage Java Server Pages (JSP) development platform is utilized in the system. SQL (Structured Query Language) Server database is applied to save and access images information, network messages and users' data. The reliability and security of the system is further strengthened by the access control. The software in the system is made to be cross-platform so that multiple operating systems (UNIX, Linux and Windows operating systems) are supported. The application of the system can greatly reduce manpower cost, and can quickly find and solve problems.
Research on test techniques of fault forewarning and diagnosis for high-end CNC machine tool
Bin Ren, Xiaoli Xu
With the progress of modern science and technique, the manufacturing industry becomes more and more complex and intelligent. It is the challenge for stable, safe running and economical efficiency of machining equipment such as high-quality numerical control because of its complex structure and integrated functions, and the potential faults are easy to happen. How to ensure the equipment runs stably and reliably becomes the key problem to improve the machining precision and efficiency. In order to prolong the average no-fault time, stable running and machining precision of numerical control, it is very important to make relative test and research on acquisition of data of numerical control sample and establishment of sample database. Take high-end CNC Machine Tool for example, the research on test techniques for data acquisition of sample of typical functional parts in CNC Machine Tool will be made and test condition will be set up; the test methods for sample acquisition on running state monitoring and fault forewarning and diagnosis of numerical control is determined; the test platform for typical functional parts of numerical control is established; the sample database is designed and the sample base and knowledge mode is made. The test and research provide key test techniques to disclosure dynamic performance of fault and precision degeneration, and analyze the impact factors to fault.
Resistance spot welding inversed imaging based on the truncated total least squares regularization
Naifeng Fan, Zhen Luo, Wenbo Xuan, et al.
Resistance spot welding is an important technology in the field of automobile manufacturing, the quality of nugget determines the quality and strength of body to a large extent. It is, however, irrational to apply the resistance spot welding to the dominations higher requirement to the quality of nugget for the limitation of the quality control. In this paper, based on the electromagnetic theory, the inversion theory is introduced to analyze the spot welding process. First, the magnetic field around the nugget is detected, with which the current density distribution in the welding nuclear can be calculated inversely, where the truncated total least squares (TTLS) method is recommended to solve the inverse problem. The result shows that inverse images can basically reflect the current distribution in the cross section of nugget under different welding currents.
Design of the high-speed roundness measurement system based on PVDF film transducer
Yang Zhou, Ming Kong, Jun Zhao, et al.
For the demands of high speed and efficiency of on-line measurement of roundness in machining industry, a kind of High-speed roundness measurement system based on the piezoelectric displacement transducer that used the Polyvinylidene fluoride film was developed. It can achieve the goal of high-speed roundness measurement by combining with charge amplifier and taking advantages of transducer such as the high frequency, sensitivity and signal-to-noise ratio. From the experiment study, known that the measuring frequency response of the PVDF transducer is over 1200Hz and the resonance peak is about 3000Hz. It has solved the problem of distortion measurement that caused by the inductive transducer in high-speed measurement. The results showed that this system roundness error measurement precision can reach less than 1μm. Repeated measurements show that the measurement results of the system has high reproducibility and reliability.
Research and exploitation of CNC laser manufacturing online monitoring system based on OpenGL
Gang Wang, Shengsun Hu, Mingjian Wang, et al.
CNC manufacturing online monitoring technology is a significant method to improve the processing quality and achieve an important part of intelligent processing. Based on OpenGL 3D graphics technology, a Computer Numerical Control (CNC ) Laser Manufacturing 3D model is established; based on the model and the powerful ability of OpenGL, a CNC manufacturing on-line monitoring system is developed so as to achieve the ability of CNC remote real-time online monitoring in different working locations. Remote real-time online monitoring of different position of the CNC is realized. The online monitoring scope of the CNC is enlarged, with more flexibility to meet the demands of practical application, meanwhile the cost of hardware investment is greatly reduced.
Electronic accelerator pedal optimal design of intelligent test system
Quanling Li, Min Lin, Bin Guo, et al.
Developed an intelligent test system for the electronic accelerator pedal, and optimized it. The system uses the three-dimensional motion platform driven by servo motor to realize to control the movement of the electronic accelerator pedal automatically and uses the least squares method to optimize the data for the electronic accelerator pedal which is integrated with linear Hall sensors. Carried on the test experiment to the double electric potential signal output electron accelerator pedal and the results show that the system has excellent dynamic and static performance, and the change of motor parameters and load disturbances has strong robustness. Performance indicators have reached the Euro III emission standard configuration of the electronic accelerator pedal and the new technical requirements.
Combining topological analysis matrices-based active learning on networked data classification
Xiaoqi He, Yangguang Liu, Xiaogang Jin
Active learning is an important technique to improve the learned model using unlabeled data, when labeled data is difficult to obtain, and unlabeled data is available in large quantity and easy to collect. Several instance querying strategies have been suggested recently. These works show that empirical risk minimization (ERM) can find the next instance to label effectively, but the computation time consumption is large. This paper introduces a new approach to select the best instance with less time consumption. In the case where the data is graphical in nature, we can implement the graph topological analysis to rapidly select instances that are likely to be good candidates for labeling. This paper describes an approach of using degree of a node metric to identify the best instance next to label. We experiment on Zachary's Karate Club dataset and 20 newsgroups dataset with four binary classification tasks, the results show that the strategy of degree of a node has similar performance to ERM with less time consumption.
Measurement and analysis to DIW of chassis dynamometers for automobile emissions testing
Weimin Zhu, Dayong Wang, Fang Qi, et al.
DIW (Dynamometer Inertia Weight) of 'chassis dynamometers for automobile emissions testing' is a total inertia weight of all rotating components in the chassis dynamometer. Total Inertia weight is a inertia device simulates translational and rotational kinetic energy of a traveling vehicle which is equivalent to the mass of the car. DIW is an important technical indicator, whether it is accurate or not will affect the calibration of all technical characteristics of 'chassis dynamometers for automobile emissions testing'. In this paper,first of all, we introduce a new method to measure the Dynamometer Inertia Weight, that is, coast-down testing with twice constant-force loading method, and we derivate a formula to calculate the Dynamometer Inertia Weight from kinetic energy conservation law. Secondly, we have done a lot of coast-down testings with twice constant-force load method. After analyzing the data, we found out the factors that affect the testing processes and the accuracy of testing results. Finally, after comparing twice constant-force loading method with the take-down flywheel method and twice constant-power loading method, we know that this coast-down testing with twice constant-force loading method is better than other methods in stability and repeatability and testing data will be more accurate. It's a accurate and convenient way to measure the DIW of 'chassis dynamometers for automobile emissions testing'.
Research of strategy for automatic measurement of sheet thickness
Weidong Yang, Zhanbiao Gao
Thickness measurement is the one of most fundamental measuring field. An optical method is developed for measuring the sheet thickness in real time. The automatic measurement strategy is studied which is used to realize intelligent measurement for thickness measurement equipment using a laser system. Base on the variations of measuring spaces, the status for laser sensor positions is built. The rule between sensor's position relation and measurement validity of difference measurement system with a pair of laser beams is studied; the optimal position adjusting aim under different thickness conditions of sheet to be measured is set up. According to this aim, the adjustment strategy in sheet thickness measurement system with laser is put forward to make the sensor at optimal positions during thickness measuring process based on the status. The method has the advantages of efficiency, precision and high-automation.
Development of an on-line measuring and monitoring system for fouling based on Delphi
Yuanyuan Wang, Jianguo Wang
The presence of fouling reduced the heat transfer capability of heat transfer equipments and increased the flow resistance of the medium. Thus the resulting series of economic losses received worldwide attention of the relevant heat transfer industry and countries. For the heating system fouling, direct measurement is nearly impossible. And it is extremely difficulty of structuring mathematic model. Although there are existing monitoring methods, results are not satisfactory. This paper intends to develop a new on-line measuring and monitoring system for heating system fouling. The operating theory of this on-line measuring and monitoring system is based on the soft-sensor technology and Expert System. We select some easily measurements as primary variables, such as pressures, flow rates and temperatures. Through some algorithms, we obtained dozens of secondary variables, for example, the coefficient of flow resistance, the efficiency and cost of heating system and so on. Based on these variables, we construct the knowledge base of this System. This system mainly uses Delphi and Excel as development tools. Now, the system is running well in some heating station, and has reached the expecting result.
Information integration and diagnosis analysis of equipment status and production quality for machining process
Tao Zan, Min Wang, Jianzhong Hu
Machining status monitoring technique by multi-sensors can acquire and analyze the machining process information to implement abnormity diagnosis and fault warning. Statistical quality control technique is normally used to distinguish abnormal fluctuations from normal fluctuations through statistical method. In this paper by comparing the advantages and disadvantages of the two methods, the necessity and feasibility of integration and fusion is introduced. Then an approach that integrates multi-sensors status monitoring and statistical process control based on artificial intelligent technique, internet technique and database technique is brought forward. Based on virtual instrument technique the author developed the machining quality assurance system - MoniSysOnline, which has been used to monitoring the grinding machining process. By analyzing the quality data and AE signal information of wheel dressing process the reason of machining quality fluctuation has been obtained. The experiment result indicates that the approach is suitable for the status monitoring and analyzing of machining process.
Form-free measurement for complex surface without given mathematical model
Zhaoyao Shi, Bin Zhang
Traditional measurement mode cannot measure the geometries without theoretical forms and parameters. Form-free measurement mode is presented to measure those geometries with high accuracy and efficiency. Critical techniques such as geometrical information extraction, form recognition and deviation assessment are analyzed. The automatic adaptive sampling strategy based on the local geometrical information is discussed. Six arithmetic operators for fast form recognition are derived. The probe radius compensation method is introduced. And deviation assessment based on Chebyshev approximation is analyzed. Form-free measuring mode is an evolutional innovation on precision measurement technologies and instruments.
Multi-variable PID neural network decoupling algorithm in scrap copper smelting process control
Yingdao Li, Zhihuan Song
In order to eliminate the coupling between the loops for control in the system of scrap copper smelting, we propose the methods to built the dynamic models of inverter-fan-furnace pressure loop and natural gas and combustion air flow-air fuel ratio-furnace temperature loop based on data-driven, established the thought of multi-variable control model with the amount of scrap copper, gas flow and speed of fan as input, temperature and pressure of furnace as output, then use the method of PID neural network to decouple. Simulation results show that the control system be with the features of fast response, small overshoot and without static error, and also multi-variable PID neural network adjusts the connection weights based on the effect produced by the changes of object parameters, achieve the decoupling of the coupling variables effectively; as with reference to the PID control requirements, making the whole system be simple and standard.
Task-driven equipment inspection system based on safe workflow model
Xinyou Guo, Yangguang Liu
An equipment inspection system is one that contains a number of equipment queues served in cyclic order. In order to satisfy multi-task scheduling and multi-task combination requirements for equipment inspection system, we propose a model based on inspection workflow in this paper. On the one hand, the model organizes all kinds of equipments according to inspection workflow, elemental work units according to inspection tasks, combination elements according to the task defined by users. We proposed a 3-dimensional workflow model for equipments inspection system including organization sub-model, process sub-model and data sub-model. On the other hand, the model is based on the security authorization which defined by relation between roles, tasks, pre-defined business workflows and inspection data. The system based on proposed framework is safe and efficient. Our implement shows that the system is easy to operate and manage according to the basic performance.
Embedded high-speed image acquisition system based on PC/104-plus
Yong Lv, Qingrui Yi, Kai Wang, et al.
In order to meet requirements of the image acquisition system with high-speed, multi-channel, scalable, low power consumption and small volume in industry, military, aviation, and so on, a high-speed embedded image acquisition system based on PC/104-Plus is designed in this paper, it combined versatility and scalability of PC with compact, small size and light weight of the embedded systems. Embedded PC/104-Plus computer is used as the master-control unit, through different IEEE-1394 high-speed serial buses, images sent by different CCD cameras are accepted and processed by the master-control. The result shows that this system is high-speed, credible and stable.
Integrated measure and control system for textile machinery
Yuantao Liu, Jinzhi Zhao, Zexiang Zhao
In this paper, textile mechanical drive control is researched. Textile machinery integrated measure and control system is established. The system is composed of micro-computer, PLC, transducer, implement device, all kinds of detective components and industrial Ethernet etc. Technology of industrial field bus control and Internet technique are applied. The system is on a background of textile production technique, such as spring, woven, chemical fiber, non-woven, dyeing and finishing. A network based open integrated control system is developed. Various characteristics of production technique flow and textile machinery movement discipline are presented. Configuration software is introduced according to user's control tasks. Final remote automatic controls are finished. This may make development cost reduced, and development periods shortened. Some problems in textile machinery development process are solved, which may make transparency factory and remote development realized.
POD-based reconstruction field of temperature in Navier-Stokes flow
Hongwei Guan, Weihong Zhong, Yingdao Li, et al.
In formulating mathematical models for dynamical systems, the model must be useful for its intended application. In general qualitative correct models are very complex. The model reduction step becomes a crucial step in the development of optimization and estimation techniques for large scale systems. Proper orthogonal decomposition (POD) based techniques have been broadly applied to flow control and optimization problem. POD is based on second-order statistical properties, which result in a set of empirical eigenfunctions (also called spatial modes) from a collection of data. These modes are used in a weighted residual method to obtain a finite dimensional low-order dynamical system which has the smallest degree of freedom possible. In this article, firstly, we extract structural information from large amounts of data obtained from the simulation. Secondly, we design a observer for reconstruction the field. Finally, by a simulation it proves the effectiveness of this kind of simple low-order representation.
Nanoparticle detection by microfluidic resistive pulse sensor with optical evidence
Hongpeng Zhang, Yongxin Song, Xinxiang Pan, et al.
This paper reports a device that performs nanoparticle detection with a microfluidic differential Resistive Pulse Sensor (RPS). By using a single microfluidic channel with two detecting arm channels placed at the two ends of the sensing section, the microfluidic differential RPS can achieve a high sensitivity allowing the detection of nanometer size particles. Two-stage differential amplification is used to further increase the signal-to-noise ratio. This method is able to detect nanoparticles of 490nm on a microfluidic chip. An 8μm gate and a 2.7μm gate detected the 490 nm particle. The electrical signal was with optical evidence. The result showed 2.7μm chip can realize signal to noise ratio higher than 10. The method described in this paper is simple and can be applied to develop a compact device without the need of bulky, sophisticated electronic instruments or complicated nano-fabrication processes.
Wavelet OHIF Elman neural network model and its predictive control of processing quality
Guixiong Liu, Jie Yang
There are some difficulties in build the process quality prediction model based on Elman neural network. The traditional Sigmoid activation function often used in the hidden layer, while it is difficult to establish a quantitative relationship between the network size and resolution scale, therefore, a wavelet OHIF Elman neural network model is proposed in this paper, which full use of the neural network weights of the linear distribution and learning convex objective function, so it can avoid the local optimal nonlinear optimization problems. Simulation results show that the wavelet Elman OHIF Elman network decreased 12.9 percent compared with OHIF Elman network which used the sigmoid activation function in hidden layer.
The processing quality prediction based on the OHIF Elman neural network
Jie Yang, Guixiong Liu
Quality prediction and control methods are crucial in acquiring safe and reliable operation in process quality control. Considering The standard Elman neural network model only effective for the low-level static system, then a new OHIF Elman is proposed in this paper, three different feedback factor are introduced into the hidden layer, associated layer, and output layer of the Elman neural network. In order to coordinate the efficiency of prediction accuracy and prediction, LM-CGD mixed algorithm is used for training the network model. The simulation and experiment results show the quality model can effectively predict the characteristic values of process quality, and it also can identify abnormal change pattern and enhance process control accuracy.
Integrated quality control architecture for multistage machining processes
Jie Yang, Guixiong Liu
To solve problems concerning the process quality prediction control for the multistage machining processes, a integrated quality control architecture is proposed in this paper. First, a hierarchical multiple criteria decision model is established for the key process and the weight matrix method stratified is discussed. Predictive control of the manufacturing quality is not just for on-site monitoring and control layer, control layer in the enterprise, remote monitoring level of quality exists a variety of target predictive control demand, therefore, based on XML to achieve a unified description of manufacturing quality information, and in different source of quality information between agencies to achieve the transfer and sharing. This will predict complex global quality control, analysis and diagnosis data to lay a good foundation to achieve a more practical, open and standardized manufacturing quality with higher levels of information integration system.
Research on form factors affecting the thermal deformation error of mechanical parts in high-accuracy measurement
Zai Luo, Ying Qu, Bin Guo, et al.
Expanding with heat and contracting with cold are common physical phenomenon in the nature. Variation in temperature leads to corresponding variation in physical dimension of mechanical parts. The conventional theories and calculations of thermal deformation are approximate and linear, can only be applied in normal or low precision field. The shortages of conventional calculations are pointed out. According to the research results of many years, a theory is given that the thermal deformation error of mechanical parts doesn't follow the conventional linear formula, it relates to all physical dimension of the mechanical part, and the deformation can be indicated by a nonlinear formula of physical dimensions. Studies on some common mechanical parts in precision technology have went on and the mathematical models have been set up, cylindrical piece, hollow piece and sphere are included. The experimental results also make it clear that these models are more logical than the traditional one. Because the sphere has only one physical dimension, so the thermal expansion coefficient can be achieved by detecting the thermal deformation of the sphere, and this method is more logical than the traditional method.
Finite element simulation of materials's stress and strain in micro-milling
Y. Z. Sun, H. T. Liu, Y. C. Liang, et al.
The material of alloy steel 40CrNiMoA's micro-milling process was simulated using the finite element method, with is built up with the Johnson-Cook coupled thermo-mechanical model , shear failure principle and Modified Coulomb friction law.. The distributions of the Mises stress, logarithmic strain, equivalent plastic strain and strain rate were obtained through finite element analysis. Meanwhile, the material's stress-strain curves of cutting deformation zones, formed surfaces, cutting chips and nearby cutting edge were given. These curves are very different from those stress-strain curves when the material is only stretched. There is no partial deformation stage on the curves of the first deformation zone, and there exists fierce indented fluctuation on the curves of deformation zone and the chip partial deformation stage. There are still exist some stress and strain no matter cutting chips or formed surfaces have reached stable.
Self-adaptive selection and decision optimizing method of failure prediction based on equipment vibration signal
Guoxin Wu, Xiaoli Xu, Hongjun Wang
The status monitoring and failure detection for equipment operation have always been important means to protect equipment for its safe and reliable operation. Therefore, establishing of a self-adaptive selection and decision optimizing model based on trend prediction method can self-adaptively select trend prediction method according to actual operating status so as to improve failure prediction accuracy and expand application range of failure prediction. The failure prediction experimental device was established to verify the practical application of optimal objective function in the fault prediction. The self-adaptive selection and decision optimizing method, which realizes the failure prediction for large size rotating equipments base on vibration signal, not only can adapt failure predictions of different rotating equipments, but also can realize the real-time online prediction for rotating equipment status; moreover, it has self-adaptive judgment method for multiple vibrating trend prediction models so that the optimal prediction results has high judgment success rate. Meanwhile, it provides trend prediction method adopting multiple prediction models and provides prediction results conducted by multiple prediction models. Compared with historical actual value, it has higher judgment value of failure early warning.
Development and design of a late-model fitness test instrument based on LabView
Ying Xie, Feiqing Wu
Undergraduates are pioneers of China's modernization program and undertake the historic mission of rejuvenating our nation in the 21st century, whose physical fitness is vital. A smart fitness test system can well help them understand their fitness and health conditions, thus they can choose more suitable approaches and make practical plans for exercising according to their own situation. following the future trends, a Late-model fitness test Instrument based on LabView has been designed to remedy defects of today's instruments. The system hardware consists of fives types of sensors with their peripheral circuits, an acquisition card of NI USB-6251 and a computer, while the system software, on the basis of LabView, includes modules of user register, data acquisition, data process and display, and data storage. The system, featured by modularization and an open structure, is able to be revised according to actual needs. Tests results have verified the system's stability and reliability.
Analysis and implementation of cloud computing network structure
Hongyao Ju, Rui Wang
Cloud computing network is a comprehensive network system with high performance and super service capability, which mainly integrated with several relative low-cost network entities through cloud computing technology. Through research of technology of network task classification scheduling and network load balance cluster, we integrate effectively with this two kinds of technologies and meet the basic requirement of cloud computing network preliminary. System test result shows that task classification scheduling is more efficient and stable. Load balance cluster, which implemented by virtual VIP technology, can bear a large number of concurrent network access and access more efficiently.