The concentration of pepsinogen II in human serum is an important index for the detection of atrophic gastritis. In recent years, the serum pepsinogen tests are proved to be a screening way for gastric carcinoma. A portable microscope imaging system combined with lateral flow strips labeled by fluorescent microsphere for quantitative detection of pepsinogen II was developed, which use immunochromatographic assays. The imaging system used 365-nm ultraviolet LED as the excitation light source, and captured the test strip images through portable microscope. A modified two-dimensional maximum entropy segmentation algorithm is applied to analyze the result. Human serum of 8 different PGII concentrations is used as samples. 10 repeated experiments are carried out on each serum of PGII concentration, and the CV values for the data of each PGII concentration are less than 5%. The fitting curve is drawn according to the experimental data, and the fitting degree is 99.67%. Afforded high linearity within PGII levels of 5.62–240 ug/mL (R2= 0.9919),the limit of detection is 4.72ug/ml. It demonstrated that the device could realize rapid, stable detection for PGII concentration in human serum.

In the phase measuring deflectometry, the phase error caused by the nonlinear intensity response, called the gamma distortion, can negatively affect the measurement quality of specular surfaces. Based on the generic exponential four-step phase-shifting fringe modal, this paper proposes a flexible and simple phase retrieval method to eliminate the phase errors without complex calibration or additional fringe patterns. The experimental results illustrate that the proposed method can accurately retrieve the phases from the distorted fringe patterns with the Gamma distortion, and the measurement precision can henceforth be improved.

With the development of science and technology, scanning electron microscope - energy dispersed spectroscopy (SEM-EDS) with its advantages of convenience, easy operation and high reliability become the most widely used instrument in micro-beam analysis field. EDS sometimes is considered as a semi-quantitative or even qualitative instrument compared with WDS and other chemical methods in element type and composition analysis. However, SEM-EDS can provide accurate results if parameters are set properly. This paper discusses how to improve the accuracy of EDS quantitative analysis by changing SEM and EDS working conditions.

A measurement based on error separation was used to measure the inside and outside squareness of the square. In the measurement, one squareness measuring system was used as the main standard whose error could be separated and eliminated. So this method could improve the accuracy of the measurement results. The uncertainty of measurement results are evaluated using the method in Aplac Interlaboratory Comparison Proficiency Testing Program M026 Calibration of Square, and referring to ISO/IEC Guide 98-3-2008.

Based on the relationship model between the interference fringe shape and the interference angle, a method that applies the four-quadrant detector to recognize the interference fringe shape is presented. The theoretical formula about the shape parameters of interference fringes with the phase difference of signal obtained by the detector has been deduced using the algorithm of area integration for the intensity of interference fringes, and the relationship between the phase difference and the interference angle is given. The dynamic modulation of the interference fringes is realized by using PZT to drive the reference mirror uniformly, and the recognition accuracy of signal phase difference has been improved. The phase difference from 0 to π is achieved with high precision through the ellipse fitting technology, and the identification of the phase difference in the range (-π, π) can been achieved combined with a specific sinusoid and cosine integral calculation, so the measurement of deflection angles can be realized. Comparing with the traditional recognition method that uses the shape of CCD stripe, this method expands the measurement range of the angle, and is more suitable for dynamic measurement. Comparing with high-precision autocollimator, experiment results demonstrate that the precision is 3 arcsec for the range from -300arcsec to 300arcsec, and the measurement owns high precision.

A new five-axis coordinate measuring machine virtual model is developed, but yet which adds more parameter errors due to the addition of more axis. Through the analysis of the axis errors configuration of five-axis coordinate measuring machine, homogeneous transformation matrix is used to established a structure model of five-axis coordinate measuring machine, and then, measuring software is combined with new utensils on the error multistage correction of the virtual model. Finally, with the help of a simulation example, demonstrating this virtual model of five-axis coordinate measuring machine effectively improved the convenience and accuracy of the measurement. The virtual machine is used to mimic real time measurements in order to come up with estimates for the task specific measurement uncertainty.

Angular displacement mechanisms are widely used in X-ray diffraction and the nrad resolution is essential for high resolution X-ray diffractor. A multi-pass differential interferometer is designed to improve the resolution of the angel to ~ 10 nrad by increasing the optical pass length. For common interferometer based on Michelson interferometry, nonlinearity is caused by phase mixing due to the imperfect of polarization optical components in both homodyne and heterodyne interferometers. In this angular measurement interferometer, the laser beam of the reference path and measuring path are separated to eliminate the mixture and to reduce the nonlinearity. The four-pass design of the reference and measuring beam improve the resolution. The performance of the interferometer can be used measure the small angle generated by compact piezo driven flexure hinge stage.

A novel type of flexure hinge based on sine-cosine function notch is proposed. Its cutting width is half cycle of sinecosine function and cutting depth is maximum of sine-cosine function. Based on the bending theory, Hooke's law and calculus superposition principle of variable cross-section beams in material mechanics, a more concise formula for calculating rotational flexibility and tensile stiffness is derived and verified by finite element method under different structural parameters. The remarkable degree of influence of different structural parameters on flexibility was analyzed. By defining the flexibility accuracy ratio function, the performance of flexure hinges are compared with that of three typical flexure hinges of circular, elliptical and parabolic. The results show that the maximum error between the finite element solution and the analytical solution of rotational flexibility and tensile stiffness are less than 7%, which verified the correctness of these formulas. Flexibility is inversely proportional to minimum thickness, cutting width parameters and cutting depth. Flexibility is most sensitive to the change of minimum thickness. At the same time, performance analysis show that these kinds of hinges are very suitable for high precision transmission occasions

Machine vision measuring methods are increasingly used in gear measurement. Due to the small size of the fine-pitch gear, the contact measurement method has problems such as difficulty in alignment and low measurement efficiency. It is a better technical solution to measuring fine-pitch gears by machine vision measurement. Compared with the gear measurement center, the machine vision measuring method has the advantages of high efficiency and small measuring force. Gear alignment is relatively simple with the machine vision measuring method. Furthermore, multiple fine-pitch gears can be measured simultaneously, improving the measurement efficiency of fine-pitch gears. Therefore, the machine vision measuring method is particularly suitable for online measurement. However, there is no widely accepted method for the determination of the center position of the gear and the evaluation of pitch deviation in the fine-pitch gear measurement based on machine vision. In this paper, The global least squares fitting algorithm for obtaining centers of each fine-pitch gear is proposed. The experimental results show that the obtained gear center coordinates are more accurate than the gear center coordinates obtained by conventional edge detection algorithm and the centroid method. Firstly, the tip circle, root circle and gear center of the acquired gear image are calculated. Secondly, the Canny algorithm is used to obtain the gear profile. Then, data points on each tooth profile surface are obtained by classifying the gear profile. The least squares arc fitting is performed by using the data points near the reference circle on the tooth profile to obtain the intersection of the fitted arc and the reference circle. Finally, by comparing the measured value with the standard value, a single pitch deviation of the gear can be obtained. The experimental results show that the gear pitch deviation calculated by the tooth profile fitting circle is accurate and the measurement speed is fast. The measuring time of a typical gear is about 15s.

It is an effective method to improve the absolute positioning accuracy (APA) of robot’s end-effector by geometric parameters calibration. In this paper, zero reference model (ZRM) and modified Denavit-Hartenberg (MDH) methods are adopted to establish the geometric parameters model of series robot, respectively. Least squares method (LSM) is used to minimize error magnitude in a function modeled over analytical Jacobian of the robot. By carrying out the practical calibration for Staubli Tx60 industrial robot with a Leica 960 laser tracker, the experimental results verify that in robot workspaces the mean absolute positioning errors is reduced from 0.5864 mm before calibration to 0.0737 mm based on ZRM and to 0.1319 mm based on MDH after calibration, respectively. The comparative study shows that ZRM and MDH methods can enhance robot APA and the improvement by ZRM is superior to that by MDH.

In order to improve the absolute positioning accuracy of the robot, a kinematic calibration method based on the Articulated Coordinate Measuring Machine(ACMM) is proposed in this paper. To identify the kinematic parameters, kinematic model based on D-H(Denavit-Hartenberg) and kinematic calibration model based on distance errors are established. Then, the ACMM is used as the measurement instrument in the calibration process. Finally, the kinematic parameters are identified by the Extended Kalman Filter(EKF) algorithm. Experiments have been carried out in this paper, the experimental results show that this method is suitable for the identification of robot kinematic parameters and can effectively improve the absolute positioning accuracy of the robot.

Angular displacement sensor plays an indispensable role in high-precision angular measurement and position feedback. With the development of sensing technology, some traditional incremental measurement methods have been unable to meet the requirements such as anti-interference ability, lossless of power-off data information and other factors that are susceptible to environment and mechanical system changes. Therefore, this paper has proposed a method based on combined measurement for absolute measurement of time-grating angular displacement sensor, which is mainly assembling two time-grating sensors that use different pole pair in a co-prime relationship on the axis. By this method, it can build high-precision and high-resolution sensor that meets vernier-subdivision principle in the form of a combination of "fine sensor and fine sensor". The sensor model and simulation experiment results are introduced by Inventor 2016 and ANSYS Maxwell 16.0, respectively. Then, the absolute position measurement method is validated by analyzing the initial phase of the induced electromotive force of the simulation experiment results with the mathematical method. Experiment results show the absolute measurement method is feasible.

In order to remove the subdivide error and zero error to improve the measurement precision of time-grating displacement sensor angle measuring system, this paper proposed an error compensation method based on sparse sampling. Firstly, harmonic analysis and the error compensation model of the induction signal for time-grating sensor displacement angle measuring system is performed. Then, laser interferometer and time-grating sensor are used to synchronous sample positions at the poles and interior single-pole. Finally, the subdivide error and zero error of measurement are corrected by the compensation model. A time-grating sensor system with 72 poles are taken as subject to test, the result shows that:the peak to the peak value of the measurement error reduces from 138" to 2.69", this is to say, the accurate degree raised 51 times than before. Besides, this method provides full-circle error compensation with fully cancel the subdivide error and zero error based on sparse sampling which greatly improves the correction efficiency and measurement accuracy.

Adaptive optical systems are originally developed for the field of astronomy to eliminate image blurring aberrations induced by atmospheric disturbance. In some complex applications, such as the contactless thin adaptive mirror for large-aperture ground-based optical telescopes, displacement sensors are needed to measure the deformation of the deformable mirror and construct a local position control loop. In the past adaptive secondary mirrors, capacitive sensors are designed to measure the mirror deformation. However, they suffer problems of manufacturing, maintenance, and environment. In this paper, a high-performance eddy current displacement sensor is proposed for the deformation measurement of adaptive secondary mirrors. Simulation and optimization of the detecting coil and conductive target are carried out. A deliberate signal processing circuit is designed for weak signal detection. Experimental results of the prototype sensor indicate a resolution up to 5 nm and a linearity better than 0.1% within the measuring range of 50 μm and bandwidth of 3 kHz, which meet the basic technical requirements of the adaptive optical systems.

Digital speckle pattern interferometry (DSPI) is a high-precision measurement method for measuring the surface deformation of an object. Compared with other measurement techniques, it has the advantages of full-field measurement, real-time, non-contact, high precision and high sensitivity, which has made the technology widely concerned by the measurement community since its birth. However, the application calculation of most of the existing digital speckle interference is based on the paraxial and approximate vertical calculations, ignoring the large fluctuation range of the angle between the laser illumination direction and the CCD observation direction. It makes the measurement error of large field of view larger when the size of the object is large . Therefore, when measuring a large field of view, it is necessary to correct the existing measurement formula. This paper proposes a new method for applying digital speckle interference to large field of view measurement. Based on the basic principle of digital speckle interferometry, the corresponding compensation coefficient is obtained through mathematical relationship to compensate the measurement result of large field of view.

As a composite sintered material, polycrystalline diamond compact (PDC) is made from polycrystalline diamond layer (PCD) and tungsten carbide (WC) alloy at high pressure and high temperature (HPHT) conditions. Defects such as crack, white spots and white edge at the surface of PCD are unavoidable in the manufacturing process, which influences the appearance and performance of the product. An automatic and non-destructive method was proposed for the accurate identification and classification of surface defects. The method is based on machine vision technique and support vector machine (SVM). First, the defect models were established. In order to obtain the region of polycrystalline diamond layer, a local boundary extraction method in terms of the histogram projection gradient extremes was utilized. Then, the accurate detection of defects were realized by image filtering and feature extraction. Accordingly, seven defect features were selected as input vectors of SVM. Finally, 450 samples were trained and tested, and polynomial kernel function was selected as the kernel function of SVM model. The results show that the SVM model with optimal parameters provided a classification accuracy of 99%. The experimental results indicate that the proposed method provides defect quantification with reasonable accuracy facing various surface defects, and it provides an effective defect detection method for PDC instead of manual way that can be used for automatic detection.

Based on femtosecond laser scanning interference, this paper dedicated to the surface profile measurement of silicon wafers. Femtosecond laser has not only low time coherence, but also high spatial coherence and high measurement accuracy. This measurement system is on the basis of a Michelson interferometer. Stepping motor is used to move the measuring arm so as to scan the surface of the measuring object. Then, the reconstruction of the object’s surface profile is accomplished by the algorithm. We use a short-wave infrared camera to record the interference fringes. The surface profile is reconstructed with pixel points, so the pixel size of the camera is the key to the reconstruction. In this paper, a standard part is selected and measured, then the camera pixel is calibrated through the size of the standard part. In this paper, the grating is tested as a standard part, and the camera pixel is calibrated through the grating reticle. Finally, the surface profile of the silicon wafer was measured with the calibrated system.

This paper mainly focuses on the sphericity evaluation based on the minimum zone sphere (MZS) method in the Cartesian coordinate system. An asymptotic search method is proposed to search for the homocentric centre of MZS model and calculate the sphericity error. The search process of the proposed method consists two parts: geometric area search is implemented to obtain a quasi-MZS centre (close to the MZS centre) and 3+2 and 2+3 mathematical models dominating the minimum zone sphere are solved to obtain the MZS centre. The geometric area search is employed to fast convergence to the quasi-MZS centre by constructing a search sphere model. Some characteristic points distributed on the search sphere are selected to determine the search direction. A threshold is set to terminate the search process and the quasi-MZS centre is determined as a result. The quasi-MZS centre is employed as a reference centre to solve the 3+2 and 2+3 models to determine the MZS centre. According to the minimum conditions, the mathematical models are established to solve the two models. Then the judgment is implemented to ensure all the measured points are enveloped between the two homocentric spheres. As a result, the centre of two homocentric spheres is the MZS centre. The MZS sphericity error can be obtained as well. To verify the performance of the proposed method, simulation experiments and comparison experiments are implemented. The results demonstrated that the proposed method is effective, reliable and meet the requirement of sphericity evaluation.

To reasonably improve the reliability of batch product inspection results and reduce the influence of measurement uncertainty on product qualification, the problem of product misjudgment rate in total inspection was studied, and the quantitative formula of product quality misjudgment risk was deduced. Two kinds of errors in product inspection and the conditions for producing errors are analyzed, and the calculation formula of misjudgment rate for different errors is studied. The example results show that the proposed quantitative model can comprehensively reflect the risk of misjudgment in product inspection caused by measurement uncertainty, and the quantitative data can more directly reflect the risk of both producer and consumer sides, thus prompting the inspectors to judge the qualifications more carefully.

There are a large amount of input quantities and complicated correlation of uncertainty source which limit the reliability of the GUM method to evaluate the uncertainty of the measurement result in the fan energy efficiency test system. Based on the technical advantages of computer random sampling, Monte Carlo uncertainty evaluation method was given to solve the correlation of uncertainty sources of fan energy efficiency test system in traditional GUM method. It can be concluded through the experiment that the results of the GUM method without considering the correlation were basically consistent with the results of the MCM method obtained by computer sampling.

In order to achieve high process efficiency and ideal quality for thermoplastic products, the accuracy of temperature measurement and the response speed of temperature control are critical. A set of on-line measurement and control system for mold cavity temperature was designed and implemented. The system consists of two parts: the temperature measurement and control instrument and the PC monitoring software. The instrument uses each cavity as the monitoring point, and uses the thermocouple to measure the temperature. Through the ADC conversion, the cavity temperature can be obtained, and the temperature can be adjusted in a suitable range by controlling the heating and cooling valves of each cavity. The instrument transmits the measured temperature data and the valve status of each channel to the monitoring software via WiFi. The software draws the temperature curve, stores and judges the temperature data, and issues an alarm if it is not within the threshold range. The system can simultaneously monitor 12 cavities. The measurement temperature is between 0-250 °C, the maximum acquisition speed of the system single channel is 0.02 seconds.

Since the traditional guidance technology of the AGV (Automatic Guidance Vehicle) has high environmental requirements and insufficient guidance flexibility, an positioning and guidance system of the AGV is proposed based on an UWB (Ultra WideBand) indoor positioning technology. Firstly, a time-based bidirectional ranging method is combined with a multi-base station positioning algorithm to locate the AGV. Secondly, the error generated by the positioning result is compensated to obtain the most accurate AGV actual coordinates. Thirdly the path of the AGV in the actual environment is programmed by using the weighted A* algorithm under different road conditions. The experimental result shows that the AGV with UWB indoor positioning technology has advantages of a high guiding flexibility, simple to use, good safety, stability, and high practical value.

In order to measure the residual stress in flat glasses accurately, a new method based on Muller matrix ellipsometer is proposed. Under the transmission mode of ellipsometer, the sample with residual stress can be equivalent to a planar stress model in the direction perpendicular to the incident light. According to the stress-optic law, the magnitude of residual stress can be obtained according to the phase delay induced by residual stress in the sample. First, the phase delay can be calculated from the Muller matrix elements. Then the stress birefringence can be obtained in line with the thickness and the measuring wavelength. Finally, the residual stress can be carried out by dividing the photoelastic coefficient. The residual stress of quartz glass with a diameter of 20mm and a thickness of 3mm is measured. The phase accuracy of the ellipsometer reaches 0.1°. The measurement results of ellipsometer are in good agreement with those of dual-frequency laser interferometer, which has a higher phase accuracy than the ellipsometer. The experiment results indicate that Mueller matrix ellipsometer can be used as a new tool for high-precision, non-destructive measurement of residual stress.

Position accuracy of industrial robots is one of the most concerned issues for manufacturers and users. The methods of measuring and analyzing the performance indexes of industrial robots accurately, simply and reliably are important for evaluating the performance of industrial robots. In this paper, a set of industrial robot performance test system is developed based on the Qt (graphics application development framework) with laser trackers as the measuring device. Then, the high effectiveness of the proposed performance test system of industrial robots is verified by testing industrial robots. For the data processing of the trajectory, the processing of redundant data is very important, which has a direct impact on the accuracy of the test results. Therefore, algorithms of filtering are need to improve the stability of test system. Experimental results reveal the high reliability of the performance test system of industrial robots by comparison with commercial system.

To correct the uncertainty of the vision-based location system, a Hybrid Genetic-Newton Method (HGNM) is presented to calibrate its camera model. This method can minimize the uncertainty of the camera model by fusing the Genetic Algorithm (GA) and Newton method together. First, the camera model of the vision-based location system is built according to the image-forming rule and space geometry transformation principle of its visual measuring device. Second, the initial camera parameters generated by genetic process are iterated by Newton method until it meets the required accuracy. Otherwise, new populations will be generated again by GA and reiterated by Newton method. Third, a novel vision-based location system is designed to illustrate the application advantages of the modeling framework. The experimental result shows that the absolute error range of HGNM is [-1.1, 1.0] mm and the relative error range is [-9.49%, 0.11%]. It reveals that the accuracy of HGNM is about four times higher than LM method and up to six times higher than Newton method. In all, the HGNM is superior to traditional method when it comes to camera model calibration of the vision-based location system.

The combination of machine vision and non-destructive testing can achieve multi-dimensional evaluation of welds. This paper proposes a weld evaluation method based on the combination of line structured light and weak magnetic detection technology. The weak magnetic detection technology is used to detect the internal defects of the weld; the line structured light sensing system is used to measure the lift-off of the weak magnetic sensor and the weld, the stability of the weak magnetic detection signal is ensured, and a relationship between lift-off and peak-to-peak value model is established to provide data support for defect size discrimination; during the automatic detection process, the line structured light system is used to reconstruct the three-dimensional morphology of the weld pool surface to obtain high-precision weld profile and detect weld surface defects. The experimental device was designed and the aluminum plate weld inspection experiment was carried out. The experimental results show that the proposed method can quickly and accurately represent the weld surface morphology, and the detection effect of weak magnetic sensor on weld defects can be improved, this provides a new idea for improving the weld detection technology in practical engineering applications.

Thermoelastic damping is one of the key factors affecting the quality factor of vacuum-encapsulated resonant devices. In order to suppress the influence of thermoelastic damping, vertical slots are introduced to the MEMS resonant beams. The heat flux inside the beams are expected to be reduced through local structural optimization, thus improving the quality factor. To verify the feasibility of the proposed method, the software of COMSOL is employed to explore the inhibition effect of structural parameters such as length, width and quantity of the slots on thermoelastic damping. The simulation results show that the thermoelastic damping decreases sharply and the quality factor are improved after the slots are introduced, and the effects are strongly related to the characteristic parameters of the slots.

Ultraviolet-visible (UV-Vis) spectroscopy technology is used to measure chemical oxygen demand (COD) of water. The standard samples are prepared using potassium hydrogen phthalate. With different pretreatment methods and various modeling methods, the COD prediction models’ performance based on raw spectra are compared, and the sensitive wavelengths are selected on basis of the prediction results. In order to build prediction models with optimal performance, the water quality parameters’ effects on the detection of COD are also researched, and the experiments are carried out to find the relationship between COD and the sample’s temperature, turbidity. Then a combined method based on UV-Vis spectrum and water quality parameters is developed. The samples’ temperature and turbidity data are normalized with Min-Max Normalization method, and then different coefficients are assigned to the two parameters to form a new data, basing on the correlation coefficients of the models established by fusing the spectral information with temperature and turbidity respectively. A prediction COD model with the fusion data of water quality parameters and spectral information is established, using Partial least Squares(PLS) method. The experimental results show optimal performance (Mean ARE=2.46; RMSEP=1.92) for the prediction set. And this COD detection method set the foundation for further implementation of online analysis of water quality.

Spherical joint is provided with three dimensional rotation motion, which has been widely applied in robots, parallel mechanisms, automobiles and medical devices on account of its smooth motion, compact structure, high load capacity. If the position of the spherical joint can be detected accurately in real time, it will be helpful to improve the accuracy of subsequent mechanical control. How to obtain the rotation angle of the spherical joint in real time has attracted lots of eyes at home and abroad. Currently, there are many kinds of measuring methods and instruments in this field. Focusing on the different measurement principles, as well as the measurement strategies, we systematically summaries the technology involved, which includes the recent work of our team. Their principles, advantage and disadvantages are analyzed, and the trend of development is also discussed in the paper.

In this paper, the converter of a 2MW direct-driven permanent-magnet wind turbine is researched for exactly locating the open-circuit fault of wind power converter. The structure and fault characteristics of the converter is analysed, and open-circuit fault location of the converter is implemented by defining a fault feature variable based on grid-side current signal. Based on Matlab/Simulink platform, the fault simulation model of wind power converter is built, the waveforms changes of grid-side current and fault feature variables are analysed under different fault conditions. The simulation results show the feasibility and effectiveness of the model. It provides a fast-position diagnosis method for the open-circuit fault of wind power converter, and has the certain application value for project.

The droplet analysis technology and the detection principles of water quality parameters are combined to achieve quantitative detection of multi-parameter of water. The detection platform is designed based on fiber and capacitance droplet analysis technology, which is mainly composed of the droplet sensor, dissolved oxygen probe, liquid supply pump, photoelectric conversion elements, and the signal processing circuit. The detection of three quality parameters (refractive index, turbidity and dissolved oxygen) is carried out on this platform through experiments. For the turbidity of the water, the sample’s rainbow-peak value of the fingerprint obtained with the droplet sensor is proved to be highly correlated with turbidity. And the prediction model of turbidity is established by regression analysis method with Formazine standard solution, with he maximum relative error 3.9%. The measurement model of dissolved oxygen is researched by collecting the fluorescence signal excited by the dissolved oxygen probe and the sample’s temperature, and the performance of the BP neural network model and the regression model is compared. And it shows that BP neural network model performs better in the detection of dissolved oxygen. The measurement model of refractive index is determined through regression analysis, and the value of the rainbow-peak is selected as the key factor through the experiments with NaCl solution. The establishment of the three parameters’ detection model shows us a method to realize multi-parameter detection for environmental water quality.

In order to meet the requirement of short delivery time, high quality, high efficiency and intelligent requirements of the gear industry, this paper presents a standard language GXML (Gear Extensible Markup Language) for gear measuring based on XML. Through the analysis of data characteristics in the whole cycle of gear, GXML is designed to standardize the data in the transmission process of gears. The experimental results showed that the data exchange mode based on GXML and the mapping between GXML documents and databases can achieve cross-platform data transmission, improve the production effectively and reduce production costs.

This study presents the design and model of a XY parallel inertial drive mechanism (PIDM) based on piezoelectric bending actuators. Mechanical structure of the PIDM and its working principle are introduced. A dynamic model of the XY PIDM is established with simplification of mechanism and expansion of friction force. With extracted dynamic model parameters, numerical simulations of the XY parallel motions are implemented using software MATLAB/Simulink. Stepping responses of the single DOF motions and cooperative planar motions with various driving parameters are analyzed.

Steel tape is a commonly used length-measuring tool, which needs to be verified before using. In this paper, a method based on image processing for steel tape verification, which replaces the traditional eye detection, is proposed. Firstly, the camera is calibrated to get the pixel equivalent. Secondly, the standard steel tape and steel tape to be measured are arranged side by side on the calibration table, and the image of the integral meter is collected by the CCD camera. Thirdly, the acquired image is divided into regions, then the fine regions are further divided, and the area where the integral meter scale line locates is selected by the frame. Finally, the coordinates of the scale line at the integral meter are extracted and calculated by the method of pixel traversal and gray center of gravity. The error of the steel tape can be obtained by multiplying the difference between them by the pixel equivalent. The verification process is efficient and the results are reliable. The resolution of the measurement system can reach 0.04 mm, which meets the requirements of the measurement task.

Since the measurement accuracy and efficiency of the traditional artificial pump test method is low, a distributed pump automatic test system was designed to automatically complete various tests such as pump performance test, type (cavitation) test and idling test. Firstly, the inlet and outlet valves were controlled, and then the inlet pressure, outlet pressure, motor speed, and voltage, current, and active power parameters of the pump under various flow points of the pump were measured; Secondly, according to GB/T3216-2016/ISO 9906:2012, test results such as head, efficiency and cavitation margin were calculated; Finally, the corresponding test report was generated and stored, and the indicator characteristics of the pump were automatically determined. The system has been put into practical use. The system testing show that the system can greatly reduces pump test time, improves test efficiency and test accuracy.

The instrument is designed for wall shear stress measurement, operating with flexible hot film sensors or floating-element sensors. The hot film sensor can be used to measure the wall shear stress on curved surfaces. And the floating-element sensor directly senses wall shear stress, and the output signal has good linear characteristics. The application software of the instrument is developed to analyze wall shear stress and flow phenomena of the boundary layer. The benchmark experiments of the flat plate were conducted in wind tunnels to show that the instrument with hot film sensors has a related normalized standard deviation of 1.02%, and with floating-element sensors has a related normalized standard deviation of 0.92% and a good linearity of 1.5%. And dynamic calibrations of the instrument with floating-element sensor show that the instrument has a dynamic response up to 6500 Hz.

In order to compensate the measurement errors of the on-machine measurement system caused by the XY worktable error accurately under the influence of multiple factors, the structural characteristics of the XY worktable are analyzed in detail. The dynamic positioning error model of the XY worktable motion components such as the grating measurement systems, the ball screw assemblies, the guide rail system manufacturing errors and the friction forces under the influence of the above factors are established, and the theoretical model of the dynamic positioning error of the XY worktable is derived. It can be seen from the analysis process that the main factors affecting the dynamic positioning error are the movement speed of the worktable, the weight of the workpiece to be measured, the installation position of the workpiece and the friction force. The actual model parameters are substituted into the theoretical model to calculate the dynamic positioning error of the worktable under different influencing factors by using the technical indicators of the experimental platform. From the analysis of calculation results, it can be seen that the dynamic positioning error is the smallest when the moving speed of the worktable is 12 mm/s, and this velocity is defined as the best measuring speed，which lays a good theoretical foundation for improving the dynamic machining accuracy of machine tools and the measurement accuracy of on-line measurement system.

A compact measurement system to measure four-degree-of-freedom (4-DOF) geometric errors of machine tools is presented in this paper. The angular errors and the straightness errors of the machine tools can be detected simultaneously by only one single laser beam, one position-sensitive detector (PSD) and one four-quadrant photodetector (QPD) through a simple optical configuration. The 4-DOF system has been calibrated and an API XD laser system is used as a reference. The straightness and angular measurement range of the system are ± 100 μm and ± 200 arc-sec, respectively. The resolution of straightness and angle measurement is 0.1 μm and 0.5 arc-sec, respectively. The developed measurement system was assembled on a machine tool with a carrier platform which has been moved 800 mm with an interval of 50 mm. A similar measurement was also conducted by the API XD laser system. The measuring results show that the maximum straightness residual is less than 2 μm and the maximum angular residual is less than 2 arc-sec. The experimental results show that the system have a straightness repeatability of ± 2 μm and an angular repeatability of ± 2 arc-sec. The developed 4-DOF measurement system can be easily assembled for geometric error measurement of machine tools in the industrial fields.

A gas sensor is designed based on a triangular lattice air-hole photonic crystal waveguide (PCW), and the concentration of the mixed gas is measured by selectively coating a sensitive film whose refractive index changes with the gas concentration in the PCW. The transmission characteristics of light in the waveguide are studied by time domain finite element method (FDTD). The results show that the appropriate structural parameters can be selected, and the mixed gas of methane and hydrogen can be accurately measured by using two channels without interference. The sensor has compact structure and good optical properties, which provides a new idea for the detection of various gases.

The working state of the pitch motor has a great influence on the operation of the wind turbine. In this paper, the 2MW wind turbine is taken as the research object. Based on the historical operation data of the wind turbine, the influencing factors of the pitch motor temperature deviating from the normal range are analyzed. First, the range of the pitch motor temperature is counted by the quartile method. Then, using Relief-F for feature selection, the characteristic parameters that have a great influence on the pitch motor temperature are screened out. According to the selected characteristic parameters, combined with the historical operation data of the wind turbine, the influencing factors of the abnormal temperature of the pitch motor are analyzed. Through analysis, it is found that the blade pitch angle, the pitch motor current and the battery box temperature show obvious trend changes in the period before and after the abnormality of the pitch motor temperature. They are related factors that affect the abnormal of the pitch motor temperature. The main meaning of this paper is to screen the characteristic parameters that affect the pitch motor temperature through the Relief-F algorithm. The selected characteristic parameters are representative and can be used as the input parameters of the prediction model of the pitch motor temperature. It can better deal with the difficult problem of parameter selection for early warning model modeling.

Target tracking is an important research direction in the field of machine vision. How to quickly track the target position in the time-series images is a key issue that has been widely studied. The search method determines whether the best motion vector can be quickly found, it also has an important impact on the efficiency of the measurement. The paper proposes a fast template search method for multi-scale moving target tracking, which can achieve tracking and searching targets in dynamic scenes, and measures the moving distance of the target. Compared with full search algorithm and three-step search algorithm, the measurement method in this paper can reduce the number of searches on the basis of guaranteeing the measurement accuracy. The search algorithm can avoid trapping in local optimum. For the content of the research, a discrete sampling method is proposed to solve the problem of starting point and initial step setting of the three-step search algorithm.

As an effective non-destructive testing method, acoustic emission detection technology has been widely used in structural health monitoring (SHM). This paper proposes a wireless monitoring system based on acoustic emission technology. A wireless communication system based on amplitude modulation of acoustic emission signals is designed. Envelope detection is adopted at the receiving end to retrieve the original acoustic emission signal. Compared with the conventional coherent demodulation method, the propose approach avoids the necessity of coherent carrier at the receiver node, which reduces the complexity of the system. The performance of the prototype was verified by a pitch-catch experiment using the piezoelectric transducers, demonstrating its capability for monitoring the acoustic emission signal and potential for the structural health monitoring applications.

Due to frequent changes in wind speed and wind direction, the yaw system needs to be frequently aligned with the wind direction, which may cause a series of engineering problems such as downtime caused by frequent actions. In this paper, SCADA data is used to filter out abnormal data such as shutdown and power limit through empirical analysis. Then the DBSCAN algorithm is used to filter the data to obtain a better SCADA data set. The data set is modeled by curved surface polynomial least squares. Through the analysis of the model, it is concluded that the yaw coefficient and wind speed have different influence characteristics on power. The yaw coefficient above rated wind speed has less influence on output power, and the yaw of different wind speed has different influence on power.

The blade model is a three-dimensional surface structure that uses a close-range industrial photogrammetry system to measure the blade model. This paper firstly verifies the reliability of the system detection marker point algorithm, and then analyzes the accuracy of the close-range photogrammetry system by three factors: shooting distance, number of coding points and location of the camera station. Experiments show that the shooting distance has a great influence on the calculation accuracy, while the number of coding points and camera position have a little influence. Besides, we get a better data acquisition scheme through experiments, which solve the problem that the system accuracy is easily affected by the shooting conditions, and the system accuracy is further improved.

The aim of calculating the standard value of the stator iron-core temperature of the wind turbine is to predict the wind turbine fault. At first, Simplify the calculation model of turbo generator stator iron-core temperature which temperature rise mechanism similar to that of wind turbine. The model uses the generator active power, reactive power, voltage and other operating parameters to calculate the generator stator iron-core temperature. Second, the parameters in the model were identified by the first year’s normal rated state operation data of the wind turbine collected by the wind farm SCADA system. Then, the model obtained after identification can calculate the standard value of the stator iron-core temperature under the rated working state of the wind turbine. Finally, If the standard value calculated by the model is correct, the average difference between the standard value and the measured value is related to the wind turbine failure alarm information. After calculate the standard value of the stator iron-core temperature using the fifth year’s rated state operation data, it’s easy to see that when the average difference between the standard value and the measured value is large, the wind turbine generates an alarm fault message in the adjacent time period and when the average difference between the standard value and the measured value is small, the wind turbine runs normally in the adjacent time period. This correlation indicates that the simplified model can correctly calculate the stator iron-core temperature of the wind turbine.

In this paper, an optical measurement method based on three-dimensional digital image correlation (3D-DIC) is described for load analysis of wind turbine blades. Author measured full-field strain and displacement fields of wind turbine blade model under different loads by the method and studied the deformation of the wind turbine blade model under different loads. In addition, the author evaluated the displacement accuracy of 3D-DIC method. Results show that 3D-DIC method can directly analyze the deformation of wind turbine blade model, and the displacement accuracy meets standards. At the same time, the results of load analysis will provide a theoretical basis for the load study of wind turbine blade in the future.

Bessel wave is a kind of non-diffraction wave in many types of ultrasonic field. In theory, it can propagate infinitely far without divergence. The non-diffraction characteristics of Bessel wave make it have potential application value. To quantitatively study Bessel wave, first of all, we need to calculate and analyze its sound field. There are many simulation methods, such as Rayleigh Sommerfeld method, finite difference time domain algorithm and so on. Generally speaking, these methods are time-consuming, computational complexity and low accuracy. In this paper, a simple method is proposed to simulate Bessel sound field by using the concept of angular spectrum. Firstly, the original angular spectrum is obtained by Fourier transform of the sound field distribution on the sensor boundary. Then, the angular spectrum distribution on any other plane perpendicular to the direction of sound field propagation is calculated according to the principle of angular spectrum propagation. Then, the field distribution on the plane can be obtained by inverse Fourier transform, and all the fields perpendicular to the direction of sound field propagation can be obtained. The results of the whole sound field distribution can be obtained by combining the field distribution of the plane. The simulation results of different methods show that this method has fast calculation speed and high simulation accuracy due to the introduction of Fourier transform. It can not only simulate Bessel sound field effectively, but also simulate other types of sound field. Therefore, the work of this paper has a certain significance for the study of non-diffraction sound field.

In order to solve the problem of spectrum broadening of measurement signal and reduction of laser interference ranging accuracy caused by modulation nonlinearity of frequency modulated continuous wave (FMCW) laser. A frequency modulation interference ranging method based on equal optical frequency subdivision resampling is adopted. The waveform data after equal optical frequency subdivision resampling of the target signal at different positions by the double optical path ranging system is obtained and spectrum analysis is performed. The results show that the method of equal optical frequency subdivision resampling uses the subdivided clock signal points to resample the target measurement signal with a distance greater than the optical path difference of the auxiliary interference optical path, eliminating the influence of the modulation nonlinearity of the laser, and The problem of signal distortion caused by insufficient sampling points is avoided. The maximum residual error of the equal optical frequency subdivision resampling ranging system is less than ±18.46μm and the maximum measurement standard deviation is 23.39μm compared with the laser interferometer in the 4.3m measurement range. The auxiliary interference optical path used in this method has a short optical path difference and is less affected by the environment, so that a stable clock signal can be obtained and can reduce the size and cost of the double optical path FMCW ranging system. This study provides a practical reference for long-distance, high-precision frequency modulated continuous wave measurements.

Both the deviation position and the heading deviation of the AGV are generated by its deviation from the ideal guiding trajectory during the working process. in this paper, the method of inertial guidance and QR code are applied to correct this deviation of AGV. The position deviation and heading deviation are pretreated by performing Butterworth filtering and attitude calculation on the output of the inertial device. AGV accurately locates the four corners of QR code in the field of view and corrects the output of inertial devices to realize motion correction. The experimental results show that the posture deviation can be effectively eliminated before reaching to the next QR code positioning module. The positioning accuracy is less than 0.5 mm at a speed of 0.6 m/s.

Aiming at the problem that giant magnetostrictive actuator has short stroke and is difficult to be popularized. Combining the advantages of large stroke of voice coil motor with high precision of giant magnetostrictive actuator, a coaxial integrated structure of macro-micro composite actuator with large stroke and high precision is proposed. According to the working principle of composite actuator, the coaxial integrated design scheme of composite actuator is verified by electromagnetic field simulation analysis, and in the process of macro motion in 0-20 mm, the distribution of magnetic force line of macro-motion coil, the effect of macro-motion coil on the distribution of micro-motion magnetic field, and the effect of micro-motion coil on macro-thrust are analyzed. The analysis results show that the distribution of magnetic force line is reasonable and the average axial magnetic field intensity of GMM rod is in the range of 495~640A/m in the macro displacement of 0-20mm, and that the static thrust difference of macro moving part is controlled within 4N in the stroke of macro displacement 6-14mm, which indicates that the coaxial integrated design scheme of macro-micro composite actuator is feasible. The research results provide a theoretical basis for the development of large-stroke and high-precision actuators in the field of precision manufacturing.

A non-contact and non-cooperative method of angle measurement based on digital speckle pattern interferometry (DSPI) was introduced in this paper. Studies have shown that when the illumination angle of the DSPI system was every small, the angle can be determined according to the interferometric phase distribution and the length of the measured object. Thereby a direct relationship between the angle and the phase distribution was established. In our experiments, the resolution of measurement system was 0.00025° ( 0.9”), proving that the proposed method is effective for measuring small angles. Theoretically, this method can achieve higher resolution if the measurement noise can be minimized.

Image processing technology is essential to visual navigation of AGV. Both the lateral offset and the direction deflection angle are key navigational parameters of the vision based AGV. The camera are installed at the bottom side of the AGV, which can be used to capture the white belt path of the ground. The lateral offset and the direction deflection angle are extracted by image filtering, threshold segmentation, edge detection, ribbon recognition, ribbon centerline fitting, and other related image preprocessing technology.According to the robustness and real-time performance of the image processing algorithm, the performance of image processing is verified by experiments.

Ultrasound Doppler blood flow measurement is to measure the velocity of blood flow through the frequency shift characteristics of Doppler signal. It has the advantages of high sensitivity, non-invasive, strong direction and simple operation. The simulation of ultrasonic Doppler signal is an important aspect in the research field of ultrasonic Doppler signal. Computer simulation of Doppler signal can be used to evaluate the accuracy of Doppler velocity measurement method in early stage. It is an effective way to improve the accuracy of Doppler velocity measurement. Generally speaking, the theoretical model of the existing simulation method is relatively complex and the calculation amount is large. In this paper, a relatively simple simulation algorithm is proposed to simulate the Doppler echo signal in time and space domain. This method is based on the physical concept of wave front propagation. According to the time of moving object passing through two adjacent wave front with the same phase, the relationship between Doppler signal data and primary ultrasonic signal data is determined. The Doppler signal data is established by extracting the data of the primary transmitted ultrasound signal. A simple, efficient and intuitive simulation algorithm of Doppler echo signal is realized. The experimental results show that the simulation results are consistent with the theoretical calculation. It can more intuitively simulate the characteristics of real Doppler signals, accurately simulate continuous wave Doppler signals and pulse wave Doppler signals, and provide an effective and reliable signal source for Doppler signal analysis and processing methods.

A crucial problem of applying ultrasonic guided wave flexible array transducer to weld detection is signal focusing. Thus, this paper proposes two focusing methods applied for array sensor in ultrasonic guided wave weld testing. By exciting every row of the array sensor simultaneously or not, we evaluate two methods on signal focusing. By comparing waveform and maximum amplitudes of focused waves generated by different number of rows in the transducer array, we find out that two proposed methods both have their advantages in guided wave focusing and indicate where these two methods should be used in real applications respectively. In results, the numerical simulations show that the guided wave focused by simultaneous excitation depends on the transducer array dimension, while the guided wave is independently focused by asynchronous excitation.

Compressive sensing (CS), which breaks the classical Nyquist limit and does not require a high sampling rate, can be used to recover a complete signal by using much less information and an optimization strategy. Further, it reduces the calculations required for signal reconstruction, and requires simpler signal collection and processing than other sensing techniques. It can reduce the data rate of high-resolution imaging radar systems and the amount of sampling, storage, and transmission data effectively. In this study, we first describe the basic theory model of CS. Then, we review the latest developments in radar imaging algorithms based on CS, followed by a comprehensive review of CS applications in high resolution radars, including SARs/ISARs, through-the-wall (TTW) radars, MIIMO radars, and ground-penetrating (GP) radars. This review highlights the importance of CS in simplifying radar hardware, overcoming data limitations, and improving the radar imaging performance. Next, an in-depth discussion and analysis of the advantages and disadvantages of CS-based radar imaging are presented. Finally, we highlight some of the challenges and research directions in this field.

Quantitative ultrasound (QUS) methods have been introduced in recent years for the assessment of skeletal status in osteoporosis. As an important parameter of QUS, broadband ultrasonic attenuation (BUA) has been clinically validated in terms of prediction of hip fracture risk. However, the short-term reproducibility of BUA has typically been inferior to that of dual-energy X-ray absorptiometry (DXA). Poor precision estimates may reduce the ability to detect longitudinal changes in BUA or the ability of QUS to assess response to therapy. In this paper, a new method for BUA measurement is proposed. In this method, an ultrasound signal covering range of frequencies (broadband) is passed through a patient’s heel to determine the BUA index. The amplitude spectrum of the received signal is then compared to the spectrum of a standard ultrasound bone phantom. The difference between the two spectra is then plotted against frequency, giving a straight line graph, the slope of which is the BUA index dB/MHz. The method eliminates the influence of water, fat and amplitudefrequency error, and improves the precision of BUA measurement, which is validated in 508 women ranging in age from 21 to 80 in vivo. Each subject was examined in two different methods, with foot repositioning before each examination. Precision was evaluated by calculating the coefficient of variation(CV). The CVs for the measurements reduced from 4.45% to 1.5%, which shows that our method effectively improve the precision of BUA measurement.

The position error on the end of the industrial robot is an important specification for evaluating its accuracy performance. In the ISO 9283 standard, the laser trackers and the binocular vision measurement methods are recommended to calibrate the positioning error. The calibration accuracy measured by using the laser tracker method is superior to that by using the binocular vision measurement method. Thus, this paper emphasized to study how to improve the calibration accuracy of the end position error by using the binocular vision measurement system. The high precision lengths as reference are introduced to combine with a conventional binocular vision system to make a new measurement system. The system errors of the binocular vision system can be corrected. In order to verify the correction effect, taking the industrial robot as an experiment example, the experimental results show that the absolute position error on the end of the industrial robot by using the binocular vision system with reference length constraint can reduce from 0.491 mm to 0.330 mm, and the repetitive positioning error reduced from 0.116 mm to 0.023 mm. The accuracy improved by about 33% and 80% respectively. Compared with the laser tracker measurement results under the same experimental conditions, the difference between the two are 0.34 μm and 7.80 μm. It can be considered that the corrected binocular vision calibration method can achieve the same accuracy with the laser tracker. It can be widely used for high-precision calibration of industrial robots as a means of balancing economics and precision.

Boundary slip of the liquid–solid interface of micro/nano fluid flow are of great interest, as slippage is linked with decreased drag in many applications of mirco-/nano-fluidic channels. Previous studies have seldom included a systematic analysis of the effect of roughness on the measurement and quantification of effective boundary slip at interfaces between oil and superoleophilic/superoleophobic surfaces. This study focuses on the measurement and quantification of effective slip length on rough surfaces using atomic force microscopy (AFM). The correction to the effective slip length is analyzed, then surfaces with various degrees of roughness were fabricated. Quantitative analysis of the effective slip length is presented. Results show that the surface roughness could significantly inhibit the degree of effective boundary slip on both superoleophilic surfaces in Wenzel state and superoleophobic surfaces in Cassie state immersed in oil. The oleic systems were likely to inhibit effective boundary slip and resulted in an increasing in drag with increasing roughness at the solid–Liquid interfaces.

Three-dimensional (3D) shape measurement of fringe projection profilometry (FPP) with high speed and accuracy is required in many applications. The measurement speed of FPP system is mainly limited by the low frame rate of pattern projection. Although defocusing binary patterns can be used to increase the measurement speed greatly, it will decrease the measurement depth. To this end, a novel triangular pattern generation method is proposed in this paper. By designing and projecting binary strip patterns with focused projector, images of triangular patterns can be then acquired with high frame rate. Fast and accurate 3D shape measurement can be finally obtained by using phase-shifting triangular patterns. Compared with the traditional sinusoidal patterns, the proposed method can improve the projection rate more than 4 times. Moreover, the proposed method will not decrease the measurement depth. Experimental results are given to confirm the validity of the proposed method.

In view of the problems in the mine hoisting system over-volume accident, this paper takes the vertical shaft friction type mine hoisting system as an example to establish the mechanical model of the mine hoisting system over-roll protection, and analyzes the precautions and forces of the over-roll protection process. Provide a theoretical basis for the design and safety inspection of the mine hoisting system to avoid accidents during the mine lifting process.

With the development of modern society, people have higher requirements for the properties of metal materials. However, according to the traditional performance testing method, the prepared samples will be placed under the high-power metallographic microscope for artificial observation and analysis. It has low efficiency and is greatly affected by subjective human factors. In order to finish the task of material recognition and classification of metallographic images, this paper established database and used the deep learning method to research the process and method of convolution neural network, hierarchical learning, transfer learning and so on. The two classification algorithms based on convolution neural network and hierarchical transfer learning have achieved good results for material recognition and grading of metallographic images, respectively and the highest accuracy rate of classification is 98.89%, which provide a good way of thinking and foundation for subsequent metallographic image analysis and detection.

To evaluate the angular velocity accuracy and uniformity among 0°~360° of a rotary table, two real-time angular position measuring systems were setup base on self-calibration angle encoder and ring-laser gyroscope (RLG) separately. The angular position acquisition triggered by programmable clock enabled angular velocity measurement with flexible angular interval, and realize the angular velocity calibration of the rotary table with required angular interval among full rotary circle. The calibration results obtained from self-calibration angle encoder and ring-laser gyroscope were identical and provided a series of detailed angular velocity deviation curves.The angular velocity deviation demonstrated periodic feature among 0°~360°. A series of comparisons were carried out, and then the relation between the angular velocity deviation and angular position deviation was analyzed on both of dimensional domain and Fourier domain.

The laser multi-coordinate measuring system has the advantages of high precision and wide measuring range and has wide application prospects in the fields of large-scale high-precision coordinate measurement. The positional relationship between the measuring equipment and the measured point is the key factor affecting the accuracy of the system. To quantify the influence of the positional relationship between the measuring equipment and the measured point on the uncertainty of coordinate measurement, the partial derivative operation of the coordinate solving formula is obtained. The coordinate of the measuring point and the mathematical model for measuring the distance from the base station to the measured point. Firstly, the mathematical model is simulated. The results of the simulation experiment show that the nonlinearity of the measurement uncertainty of the system increases significantly when the measured target point is close to the measurement plane composed of multiple stations. Finally, the simulation results are verified by experiments. When the distance between the retroreflector and the measuring plane is reduced from 1010.7 mm to 509.6 mm, the measurement deviation increases by 4 times. When the distance continues to decrease to 10.9 mm, the measurement deviation increases to 76 times before. The results show that the mentioned error model can accurately describe the relationship between the position of the measured point and the error of the measurement accuracy, and can provide theoretical support for the layout optimization method of the laser multi-coordinate measuring system.

Butt welding is the typical welding mode for the fiber laser welding, and penetration status of the weld is critical point to assess welding quality. For the sake of solving the prediction of the penetration status in the fiber laser welding, a sparse representation prediction model was established to monitor the welding process. The sparse representation classification algorithm of using the K-SVD algorithm constructed the dictionary was used to predict the weld penetration status. However, the dictionary trained by K-SVD algorithm was not discriminative and the prediction accuracy was low. A D-KSVD algorithm with the discriminant dictionary learning mode was proposed, and the initialization method of the initial dictionary was improved to enhance the dictionary discriminant performance. The experiment result indicates the average recognition accuracy of the improved D-KSVD algorithm is 4 percentage points higher than the D-KSVD algorithm, and the accuracy of the weld penetration status prediction can reach 0.943, which shows that the recognition accuracy of the DKSVD algorithm is significantly higher than the K-SVD algorithm, and the dictionary learning with adding the discriminant learning can effectively improve the prediction of weld penetration status.

In order to realize high precision calibration of total station, an automatic compensation system for air refractive index has been developed, including sensor array system and data processing system. The sensor array system consists of 82 temperature, humidity and air pressure sensors, forming a dense sensor array, monitoring the changes of environmental parameters along the baseline. The data processing system automatically compensates the air refractive index for different measurement sections in real time. Based on the Changping baseline of National Institute of Metrology,China, real-time and time-delay experiments were carried out to compensate the refractive index of air for the measured distance of the total station.. The experimental results show that the maximum measurement error is about 1 mm when the environmental parameters with 14 seconds delay are compensated, nearly 10% of the data reach the error of 0.5mm. The time-delay compensated measured distance will affect the accuracy. It shows that the calibration accuracy of total station can be effectively improved by using the developed automatic air refractive index compensation system.

A method is presented in order to realize the measurement of angular position and angular speed simultaneously based on the theory of time grating. A model of angular speed measurement is built by using the Doppler Effect which is produced by relative uniform motion of bi-coordinate system inside the time grating. Measure benchmarks of angular position and angular speed are unified to the time quantum by a space-equivalent V as an interim parameter between angular position and angular speed. Therefore, A uniform mathematical model is built for simultaneous measurement of angular position and angular speed. The experimental prototype of time grating is developed, and the angular position and angular speed are calculated by using FPGA (Field Programmable Gate Array). The results show that the method can effectively realize the simultaneous measurement of time grating angular position and angular speed. The experimental results show that the accuracy of angular position of time grating has reached ±4″and the angular speed stability has reached 5‰.

The camera distortion is affected by many factors such as the calibration environment, the size of the calibration object, and the number of captured images, which lead to reducing the measurement accuracy of image detection. The experimental analysis of the calibration accuracy is carried out from both the number of photos and the area division of the calibration board. The experiment of the number of photos used three different sizes of calibration board. The number of pictures with the effective focal length of the photo calibration tends to be stable is 10-18. Another experiment was used cross-division to calculate of distortion coefficient and distortion correction by cross-ratio invariance. Take the points which on the diagonal of Calibration plate image after distortion correction to calculate the average linear offset. The linear offset without partition is 0.8651 and 0.6439. And the linear offset after the sub-region is 0.6439 and 0.2817. Therefore dividing the area can improve the accuracy of distortion correction.

The high-intensity focused ultrasound (HIFU) in the clinical trials is prone to nonlinear effects, especially near the acoustic focal region, which has a great impact on the therapy effect of HIFU thermal ablation. In this paper, the Westervelt equation was introduced in theory.The HIFU transducer model was established to simulate the nonlinear ultrasonic propagation by the finite element simulation (FEM).The distortion waveform near the acoustic focal region are extracted separately, the spectrum analysis is performed and the distortion waveform is filtered. The simulations show that the nonlinear effect is most obvious in the focal area and the higher harmonics energy at the focus is very large, so the harmonics energy can’t be ignored. The study of the nonlinear effects of HIFU ultrasound field contributes to the accurate measurement of HIFU and lays a foundation for clinical trials of the HIFU systems.

Many researchers have done a lot of research in the fields of welding automation and welding robots. The existing technology can achieve better results in applications where the shape and position of the weld are relatively fixed and the weld is easier to identify. For welds with inconspicuous appearance, irregular shape and complicated background such as the casing weld on copper pipe of refrigerator compressor. The existing technology is difficult to achieve stable and accurate automatic positioning and tracking of welds. In this paper, a three-dimensional positioning method for casing welds of copper pipe based on binocular vision is proposed. Firstly, Zhang's calibration method is used to compute the intrinsic and external parameters of the binocular vision measurement system. Secondly combine with morphological operation and basic image operation, the casing welds in complex scenes are segmented accurately. Finally, the binocular measurement model is used to complete the three-dimensional positioning and tracking of the casing welds in complex scene. The measurement results show that the measurement accuracy of the system can meet the requirements of vision guided automatic welding.

This paper presents a robust and low-cost three-degree-of-freedom laser measurement system (3DOFLMS) that can measure both straightness error and roll angular error of long-travel linear stages. A low-cost laser diode is adopted as the laser source. A beam drift compensation module is employed to improve the stability of the 3DOFLMS. The relationships between the sensitivity of detector, the dual-beam parallelism and the measurement distance along the laser propagation direction are theoretical analyzed. Compensation methods are then proposed for eliminating the effects of detector sensitivity variation, beam drift and misalignment on the accuracy of the measurement system. The effectiveness of the compensation methods and the feasibility of the designed measurement system are demonstrated by a series of experiments. With the comparisons between commercial measurement instruments and the proposed measurement system in the measurement distance up to 1 m, the measurement accuracy of straightness errors and roll angular error are within ±1.0 μm and ±1.2 arcsec, respectively. The designed measurement system is very easy to construct both in the laboratory environment and in the actual measurement environment.

The dimensional accuracy evaluation and forming quality control are mainly rely on the accurate measurement of the springback of the micro-bent parts. In this paper, micro W-bending is proposed for the first time. Considering the small feature size and extremely thin thickness of the W-shaped micro-bent parts, a high-precision 2D image measuring instrument, Mitutoyo Quick Scope, was used to capture the clear image of the micro parts. QSPAK software and MATLAB image processing program were then adopted to measure the springback angle. Comparison of final bending angles obtained by QSPAK software and MATLAB program indicated that both methods could meet the accuracy requirement. Finally, the springback radii were measured using the similar MATLAB image processing program. The investigation addressed in this paper could provide an access to achieve the accurately control and prediction of the dimensional accuracy and forming quality of the W-shaped micro-bent parts.

In micro-milling, the diameter of the micro-milling cutter is smaller than tens of microns, making it difficult to achieve precise positioning with the workpiece, which affects the machining accuracy and the safety of the micro-milling cutter. To solve these problems, the coordinate system has been analyzed. A micro-milling precise automatic tool setting technology has been proposed, which based on the micro-energy pulse discharge sensing principle. A tool setting scheme is proposed to determinate the Central coordinates of workpiece, which is realized by repeating automatically the precise sense from four directions. Experiment is carried out to verify the feasibility and correctness of the technology by analyzing the perceived results.

The gap average voltage measurement method is commonly used to detect the discharge state in micro electrical discharge machining (Micro-EDM), which is simple and effective for the discharge states detection of transistor pulse power and relaxation type pulse power. In order to further explore the ultimate machining ability of micro-EDM, a very high frequency (VHF, frequency range 30MHz~300MHz) micro energy pulse generator based on the principle of circuit resonance has been developed in a previous study. It has smaller discharge energy and nanoscale discharge erosion ability compared with the traditional pulse power. Furthermore, defects in micro-EDM such as thermal damage, recast layer and heat affected zone are significantly reduced. A simulation circuit model was established to analyze the effect of the gap average voltage measurement method applied to VHF pulse generator. The results show that the inter-electrode discharge states cannot be distinguished effectively and sensitively by this means. In order to detect the discharge state of VHF pulse generator, a novel method to detect discharge state based on impedance change of inter-electrode channel was presented, which is not affected by the pulse power. Hence, when the detection circuit was fixed, the detection sensitivity and the accuracy of threshold voltage was not varied according to different pulse parameters. Both simulation and experimental studies were undertaken to verify the effectiveness of the proposed method. The results demonstrate that the discharge states of VHF pulse generator can be distinguished by this detection method.

For precise micro-EDM machine tools with high-speed pneumatic spindle, the parallelism between the axis of rotation and the existing Z axis directly determines the machining accuracy of tool electrode and workpiece, so it is necessary to adjust the parallelism between the rotary axis of the pneumatic spindle and the Z axis. Due to the small diameter and low rigidity of the tool electrode, the traditional contact metering method is difficult to apply. Therefore, based on the principle of micro-energy pulse discharge sensing, the diameter and center coordinates of the tool electrode are measured in different tool electrode sections, and the tilt between the pneumatic spindle and the Z-axis is calculated. Based on principle, the posture of the spindle is fine-tuned. This can easily and quickly adjust the parallelism between the pneumatic spindle and the Z-axis. Finally, the parallelism error of the measuring section is successfully controlled within 0.0015 mm.

A calibration method for cantilever length of non-orthogonal cantilever coordinate measuring machine(CCMM) based on the double reversal method is proposed in this paper, aiming at the calibration problems of CCMM. The cantilever length calibration restricted by virtual axis is realized by the symmetrical rotation of the cantilever of the CCMM. By the symmetrical rotation of the probe head, the other parameters of the CCMM in the calibration process can be eliminated, and then the influence of the other mechanism errors on cantilever length calibration can be negligible, and the calibration accuracy of cantilever length is then improved a lot. Experiments show that the method discussed is easy to operate. The precision and effectiveness of the proposed method is verified by actual measurement experiment and practice, such as measuring standard gauges within its measurement range.

Laser triangular displacement sensor (LTDS) is widely used in various high-precision measurement scenarios, but the accuracy of the sensor will be distinctly reduced in a working environment with extreme temperature. The mechanical structure, optical crystal and illuminant of the sensor will be distorted or drifted due to the impact of temperature change. This paper focuses on the spatial drift characteristics of illuminant on the measured surface with temperature change. The self-developed LTDS prototype is used to conduct the temperature-rising experiment of the "illuminant - collimated lens" system, and the centroid drift of the spot formed by the illuminant under two different power supply currents (16mA and 24mA) is recorded. The experimental results show that the centroid of laser spot appears clustering phenomenon in the process of heating. After filtering the noise generated by clustering phenomenon, the drift of the centroid of laser spot in the spatial plane presents a linear directional law, and the drift distance presents a quadratic function relationship with the change of temperature. In addition, the error evaluation model is used to calculate the actual measurement error of the sensor caused by the centroid drift of the spot. The measurement error of the sensor is quadratic function with the change of temperature. Comparing the results of heating experiment under 16 mA and 24 mA power supply, choosing appropriate power supply current (24 mA) can effectively suppress clustering phenomenon and improve the stability of illuminant.

When the white light interferometry system is used to measure the multi-point roughness of smooth sample surface, because there is a little tilt between the sample surface and the measuring lens, one position measurement is completed and moved to the next, the surface of the sample can easily leave the interference interval. In order to solve this problem, a method of Z-axis compensation by the width and slope of white light interference fringes is proposed. First, the mathematical model of interference fringes and inclination angle of sample surface is established; second, the relationship between interference fringes width and inclination angle of sample surface is analyzed; Finally, the compensating amount of Z-axis is analyzed when moving horizontally for a distance. The experimental results show that when the slope of interference fringes is -0.73 and the width of interference fringes is 28.40 μm, the inclination angle of the sample surface relative to the measuring plane is 0.56°. When the system moving 1 mm for the X-axis, the amount of compensation required for the Z-axis was 5.73 μm; when moving 1 mm for Y-axis, the amount of compensation required for the Z-axis was 7.89 μm. The experimental results show that the relationship between horizontal moving distance and Z-axis compensation can be determined by calculating the width slope of interference fringes. It simplifies the measurement process of the system and avoids re-focusing when moving to the next point.

In order to watch 3D images and videos with high color resolution and good visual effect with low cost, a new multi-spectral thin film of 3D glasses has been designed, which combines optical coating technology with 3D display technology to offset color cast at the image edge of current product, cumbersome and high cost disadvantages of glasses. Based on the principle that people can see different colors under different wavelengths and wavelength of each color changes in a range rather than a specific value, two multi-bandpass filters have been designed here. This thin film is applicable to 3D display technology, therefore, multi-bandpass filters designed here are more practical and significant.

High-precision position measurement and detection technology are more and more needed in the process of precision machining. This paper proposes a two-dimensional displacement sensor based on planar coil. The sensor is composed of excitation and induction coils. Two groups of excitation coil array are arranged in the x and y directions respectively, then two groups of magnetic fields which travel orthogonally are generated. The induction coil induces the variation of the magnetic field to generate two electrical signals whose phases are related to x and y respectively. The displacements are obtained after phase comparisons and calculations. A sensor model based on the principle is built and simulated in the finite element analysis software. According to the simulation results, the measurement error is traced back to the source and the structure of the sensor is further optimized. A sensor prototype is fabricated and the experiment is carried out. The experimental results show that the measurement range is 140mm × 140mm with the resolution of 1. μm, and the nonlinearity is 0.5 % in one pitch.

In speckle metrology, speckle fringe pattern includes phase information, in order to get the contains less noise in the dynamic measurement of the original speckle fringe pattern, allowing for more efficient to extract phase information,A new method is proposed to improve the quality of the original speckle pattern by changing the average speckle size on the digital shear speckle. The quantitative relationship between the optical path system parameters F number and magnification factor and the speckle size on the image surface was analyzed, and the digital shear speckle interferometry experiment based on the space carrier phase shift technology changed F number and magnification factor respectively for verification.Experimental results show that the shape of variables for fixed value, system magnification is 1, the imaging lens F value is 4.5, The average speckle size was 5.841 μm, and the image was best when it was closest to 5.86 μm, as a lens F number is 2, system magnification of 3.5, The average speckle size was 5.841 μm, and the image was best when it was closest to 5.86 μm, after filtering is cosine algorithm, the speckle fringe pattern is the most clear.It is proved that when the speckle size on the image plane is closest to the size of pixel, the quality of the speckle stripe is the best.