A passivity-based controller for motion tracking and damping assignment for compliantly actuated robots

This paper introduces a novel control approach for motion tracking and damping assignment in compliantly actuated robotic systems. The approach follows the idea of shaping the link side dynamics such that the closed loop dynamics follows a given reference trajectory while injecting additional damping for improving vibration suppression. The modification of the apparent link side dynamics is amended by a desired dynamics on the motor side. In contrast to classical feedback linearization the design aims at only a minimal modification of the dynamics, both for the link side and the motor side. The time-varying closed loop dynamics is shown to be globally, uniformly stable. The effectiveness of the resulting feedback control law was evaluated by simulations as well as experiments on a highly nonlinear and highly compliant robot arm.