Today's military operations demonstrate the value of teleoperated robotic platforms, both aerial and ground. As extensions of the human senses commanded by remote, they have found recent applications in sensor and communications systems. In complex terrains such as caves and mountains, and in urban environments, they provide capabilities that would otherwise be costly, impossible, or deadly. Future enhancements will require reduction in size and the cohesive operation of multiple platforms with little or no direct human supervision. Such platforms will support personnel in a variety of dangerous environments, such as collapsed structures after a disaster or confined spaces that may contain improvised explosives (see Figure 1).
Figure 1. Artist's conception of how small autonomous platforms might enhance human sensing in hazardous situations by working synergistically in confined spaces.
The Army Research Laboratory has positioned itself strategically to contribute to the development of such small-scale autonomous platforms. Its broad aim is to develop mobile sensor units compact enough that a single individual can carry and control several of them. They must be able to travel autonomously and maneuver in confined spaces such as alleyways, caves, and tunnels. In addition to navigation, capabilities must include obstacle avoidance and location, detection, and tracking of humans and vehicles. A further key to this vision is autonomously coordinated mobility with sensing, processing, and communications applications across multiple platforms. Efforts to create such palm-sized platforms form part of a larger strategic initiative that includes man-packable robots and full-size robotic vehicles.
To advance the development of such capabilities, in February 2008 the Army established the Micro Autonomous Systems and Technology (MAST) Collaborative Technology Alliance (CTA).1 This consortium will bring together government, academic, and industrial researchers organized around four key technologies: microsystem mechanics, processing for autonomous operation, platform integration, and microelectronics. These four are necessary to provide situational awareness under the constraints of small-scale, low-power autonomous platforms.
The MAST CTA Center on Microsystem Mechanics will be coordinated through the Alfred Gessow Rotorcraft Center at the University of Maryland, which serves as the principal member. Other principal members and associated technologies are the University of Michigan (microelectronics), the University of Pennsylvania (processing for autonomous operation), and BAE Systems (microsystem integration). Additional consortium members include the University of California, Berkeley, the California Institute of Technology, NASA's Jet Propulsion Laboratory, the Georgia Institute of Technology, the University of New Mexico, and North Carolina Agricultural and Technical State University.
Although one goal of the MAST CTA is to advance fundamental science and technology in several key areas of robotics, a more critical aim is to investigate the interplay of elements on small-scale platforms, as opposed to each element independently. Solutions to processing, communications, and mobility that are satisfactory for large systems do not scale when platforms are reduced to the dimensions envisaged. Platform size and weight, for example, limit the power available over the duration of a mission. The greatest percentage is expended on mobility, which in turn constrains the bandwidth for both intraplatform communications (e.g., between sensors and processors, processors and transmitters) and interplatform communications. These limitations further impact the ability of the microsystem collective to sense, understand, and respond coherently as a group.
The interplay of conflicting requirements is sufficiently complex that investigating a single issue in isolation will not generate an efficient and operationally effective ensemble. To achieve this goal requires the pursuit of radical design and engineering methodologies in which system-level performance, maneuverability, and functional adaptability are emphasized over optimization of individual functions. The methodology that results may prove to be a critical tool that guides platform design and architecture for the collectives of platforms.
One common theme is therefore to study small biological systems as examples of highly integrated solutions for sensing, mobility, control, navigation, and communication. Birds and flying insects, for example, use optical flow for obstacle avoidance and navigation. This principle is now being applied to robotic motion control. Another common theme emphasizes modeling and simulation combined with frequent validation experiments. One particular challenge is to combine separate software applications used by the various disciplines to create a comprehensive modeling and simulation tool for system-level design and optimization.
The small size of the planned MAST platforms places significant constraints on available power, energy, and bandwidth, which limit mobility, sensing, processing, and communications capabilities. Through a multidisciplinary collaboration, the Army hopes to address these issues using a global approach to research, development, and design. The outcome of this collaboration should benefit not just military operations but search and rescue and reconstruction efforts as well.
US Army Research Laboratory (ARL)
Since 1989 Joseph Mait has been with the ARL (formerly the Harry Diamond Laboratories), where he has served in several different positions. He is presently a senior technical researcher. He is a Fellow of SPIE and OSA, and a senior member of the IEEE.