Volume 27 Issue 3-4 - Publication Date: 1 March 2008
Million Module March: Scalable Locomotion for Large Self-Reconfiguring Robots
Robert Fitch ARC Centre of Excellence for Autonomous Systems, Australian Centre for Field Robotics (ACFR), The University of Sydney, NSW, Australia and Zack Butler Department of Computer Science Rochester Institute of Technology Rochester, NY USA
Self-reconfiguring robots have the potential to explore highly variable terrain, operating as parallel groups or combining to surmount large obstacles. If the modules are at a smaller scale, they may also be able to physically render arbitrary shapes in an interactive way. In order to realize these capabilities, groups with large numbers of modules must be used, and algorithms to control such large groups must be extremely scalable in order to be executed on simple modules. In this work, we present an algorithm for locomotion of latticebased self-reconfiguring robots that uses constant memory per module with execution times that are sublinear in the number of modules. The algorithm is inspired by reinforcement learning and uses dynamic programming to plan module paths in parallel. We have also developed a novel localized cooperation scheme that allows the modules to move both without disconnecting the system and with small amounts of communication. The combined algorithm is able to direct locomotion over arbitrary obstacles, and due to continuous replanning the goal can be moved at any time to ‘joystick’ the robot over the environment. The formulation of the goal used in the planning also encourages dynamic stability. We have developed both centralized and decentralized implementations in simulation, as well as an implementation for the Superbot system, and present empirical results showing the sublinear nature of our technique.
Multimedia Key
= Video = Data = Code = Image
Example 1: SR robot simulation over random terrain. (4.5 MB) mp4
Example 2: SR robot simulation of 125 000 modules over flat terrain. (6.8 MB) mp4
Example 3: SR robot simulation over a concave obstacle. (2.7 MB) mp4
Example 4: SR robot simulation through comb-like obstacle. (3.8 MB) mp4
Example 5: Simulation of planar Superbot locomotion. (3.7 MB) mp4
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