Non-model-based impedance control of an industrial robot

This paper introduces the various non-model-based impedance control schemes. One of the simplest approaches, the straightforward method, is presented which utilises force feedback only to determine the position adjustment necessary for controlling the dynamic behaviour of the manipulator under position control. An analysis is done to determine the stability and steady-state response of the impedance control model as well as the overall closed-loop system. The detailed impedance control algorithm, developed from the theory, is presented to facilitate the implementation and software development. Experiments are conducted to verify the desired inertia, damping and stiffness of the end-effector, as well as to compare the effects of the manipulator impedance on the position and force response during transition from free space to contact.