Abstract
Hopping on a rigid foundation results in energy losses due to impact with the foundation. A continuous and a discrete controller with integral action are developed to drive the apex height of an Ankle-Knee-Hip robot to a desired value. To compensate for the losses, the continuous controller employs negative damping while the velocity of the center-of-mass is moving upwards during the contact phase. The discrete-time controller adjusts the negative damping parameter used by the continuous controller to control the apex height. The dependence of the apex height on the controller parameters is studied to understand the role of constraints imposed by the robot structure. Simulation results are presented to show the efficacy of the control strategy.
