A New Type of Robust Tracking SP-D Control for Manipulators

Abstract

This paper is concerned with a new type of robust tracking control scheme for robot manipulators using SP-D (Saturated Proportional and Differential) feedback loops. In this paper, the control scheme based on quasi-natural potential is generalized from set-point regulation to trajectory tracking by exploiting an effective auxiliary variable which consists of a saturated positional error and a velocity error. Without any uncertainties in the manipulator model, the generalized tracking SP-D control scheme ensures globally asymptotic stability. In the presence of parametric model uncertainties, the tracking SP-D control scheme is improved in order to be robust against the uncertainties. The proposed robust tracking SP-D controller is able to guarantee globally uniformly ultimate boundedness theoretically. Experimental results on a two-link direct drive manipulator with the robust tracking controller are in agreement with the theoretical analysis and show the effectiveness of the control scheme.