Enhanced Time Delay Control and Its Application to Force Control of Robot Manipulators

Abstract

The Time Delay Control(TDC) has been proposed as a promising technique in the robust control area and has been successfully applied to robot manipulators. We have observed, however, that the force response of TDC may not track well desired dynamics(reference model)in situations that the environment, with which a robot interacts, is very stiff. Due to the high stiffness of the environment, the unknown dynamics undergoes rapid changes that the TDC is unable to estimate accurately at the given sampling frequency. In order to solve this problem, we propose the Enhanced Time Delay Control(ETDC), which estimates the uncertainties more accurately than TDC at the same sampling frequency, yet has nearly the same computational efficiency as TDC. The stability of ETDC has been analyzed. The experimental results verified that ETDC improves TDC in terms of the control performance.