Adaptive position and force control of flexible joint robots

Abstract

Develops a position and force control scheme for a class of flexible joint robots with model uncertainties based on the singular perturbation theory. A parameter adaptive law is proposed to compensate for the effects of unknown model parameters on the system performance. The controller is composed of two parts: a fast controller and a slow controller to regulate the joint elastic force, the position and contact force respectively. In the fast controller, an additional control signal is designed to compensate for the deviation of the joint elastic force from the integral manifold due to the effect of model uncertainties. The stability of the closed-loop system is analysed based on Lyapunov stability theory. It is proven that errors of the position and force in contact with an environment are uniformly bounded.