Experimental verification of a strategy for impact control

The authors present experimental results from a strategy for stable hard-on-hard impacts of a robot manipulator, and show how this method fits into the framework of force control. Previously proposed methods of impact control are reviewed, and their inadequacies are revealed. A fourth-order model of an arm/sensor/environment system is reviewed. It is pointed out how proportional gain force control with feedforward and impedance control are equivalent when the environment is stiff. An analysis of the model and the controllers shows the gain selection that provides the best impact response. Extensive experimental results confirm the correctness of the model, the equivalence of the controllers, and the efficacy of this impact control strategy