An optimized passivity-based method for simulating satellite dynamics on a position controlled robot in presence of latencies

Abstract

This paper introduces a performance oriented method for simulating stable free-floating satellite dynamics on a position controlled robot. Intrinsic latencies found in robot controllers, i.e. between input and output data, are known to produce stability issues and performance degradation. These issues are even more apparent during contact phases, where impact dynamics play a major role. The approach presented in this paper guarantees stability through passivity and preserves the performance through the use of an optimal damping. The energy produced by delays found in the closed loop system is monitored and dissipated when necessary. In order to implement the dynamics accurately, the damping process is formulated as an optimization problem. Thus, over-dissipation can be avoided and the system becomes less conservative. Performance and effectiveness of the method are shown in simulation and verified experimentally on a position controlled seven degrees of freedom Light Weight Robot equipped with a force-torque sensor at the end-effector.