Understanding the Implementation of Impedance Control in Industrial Robots

This work studies two different algorithms for the simulation and implementation of impedance control. Potential applications for using force control can be found in the whole industry and academia. Since its proposal, impedance control became one of the most used force control techniques, dealing with the non linear nature of contact and ensuring stability. To take advantage of the technique, one may implement in different ways, although, in the literature it is hard to find explicit algorithms to help the development. This paper presents two different impedance control methods that lead to similar responses to contact. Responses to force step input and contact stabilization with stiff environment tasks are presented using computer simulations as well as experimental tests. Results show that both algorithms accomplish good results for the second order controller in a no-contact situation compared to the simulation. In the meanwhile, for a stiff contact, the algorithms show a stable interaction, but with results different from the simulated, suggesting that the coupled dynamics is subject to many disturbances and uncertainties, which the impedance controller still offer a stable execution.