Sensor-Actuator-Comparison as a Basis for Collision Detection for a Quadruped Robot

Collision detection in a quadruped robot based on the comparison of sensor readings (actual motion) to actuator commands (intended motion) is described. Ways of detecting such incidences using just the sensor readings from the servo motors of the robot's legs are shown. Dedicated range sensors or collision detectors are not used. It was found that comparison of motor commands and actual movement (as sensed by the servo's position sensor) allowed the robot to reliably detect collisions and obstructions. Minor modifications to make the system more robust enabled us to use it in the RoboCup domain, enabling the system to cope with arbitrary movements and accelerations apparent in this highly dynamic environment. A sample behavior is outlined that utilizes the collision information. Further emphasis was put on keeping the process of calibration for different robot gaits simple and manageable.