A Theoretical and Experimental Investigation of Impact Control for Manipulators

Abstract

This article describes a simple control strategy for stable hard- on-hard contact of a manipulator with the environment. The strategy is motivated by recognition of the equivalence of pro portional gain explicit force control and impedance control. It is shown that negative proportional force gains, or impedance mass ratios less than unity, can equivalently provide excel lent impact response without bouncing. This result is indicated by an analysis performed with an experimentally determined arm/sensor/environment model. The results are corroborated by experimental data from implementation of the control al gorithms on the CMU DD Arm II system. The results confirm that manipulator impact against a stiff environment without bouncing can be readily handled by this novel control strategy.