Torque control strategies for snake robots

We present three methods of achieving compliant motion with a snake robot by controlling the torques exerted by the joints of the robot. Two strategies command joint torques based solely on the robot's local curvature (i.e. joint angles). A third strategy commands joint angles, velocities, and torques based on the recorded feedback from the robot while executing a previously defined motion under position control. The three control strategies are implemented and compared on a snake robot that includes series elastic actuation (SEA) and torque sensing at each joint, and demonstrate compliant locomotion that adapts automatically to the robot's surrounding terrain.