Tip-over Prevention Through Heuristic Reactive Behaviors for Unmanned Ground Vehicles
SPACE AND NAVAL WARFARE SYSTEMS CENTER PACIFIC SAN DIEGO CA
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Skid-steer teleoperated robots are commonly used by military and civilian crews to perform high-risk, dangerous and critical tasks such as bomb disposal. Their missions are often performed in unstructured environments with irregular terrain covered with a variety of media, such as sand, brush, mud, rocks and debris. During such missions, it is often impractical if not impossible to send another robot or a human operator to right a toppled robot. As a consequence, a robot tip-over event usually results in mission failure. Also such robots are often equipped with heavy payloads that raise their centers of mass and hence increase their instability. Should the robot be equipped with a manipulator arm or flippers, it may have a way to self-right. The majority of manipulator arms are not designed for and are likely to be damaged during self-righting procedures, however. Those robots not equipped with manipulator arms or flippers have no self-righting capabilities. Due to the on-board camera frame of reference, the video feed may cause the robot to appear to be on at level ground when it actually may be on a slope nearing tip-over. Finally, robot operators are often so focused on the mission at hand they are oblivious to their surroundings. Our research seeks to remove tip-over monitoring from the already large list of tasks an operator must perform. An autonomous tip-over prevention behavior for a mobile robot with a static payload has been developed implemented and experimentally validated on two different teleoperated robotic platforms. Suitable for use with both teleoperated and autonomous robots, the prevention behavior uses the force-angle stability measure previously experimentally validated, to predict the likelihood of robot tip-over and trigger prevention behaviors.
- Operations Research