Control of hopping speed and height over unknown rough terrain using a single actuator

Abstract

We present a method for controlling the forward speed and the apex height of a one-legged hopping robot over rough terrain, using a single actuator located at the robot hip. The control algorithm is comprised of two elements, the forward speed control and the height control. The only input to the system is the torque applied by the hip actuator. The control is demonstrated to perform tracking of desired forward speed trajectories and desired apex height trajectories. Simulation and experimental results on the SAHR (Single Actuator Hopping Robot) experimental setup are presented and compared. It is shown that the robot follows both trajectories closely in simulation as well as in experiment. Also the robot is tested successfully on a rough terrain course, which includes inclined ground and an abrupt drop in height of over 25% the length of the robot leg. The robot has no knowledge of its environment. Further, the robot is made to run over the course a number of times, to demonstrate the control robustness.