Chattering-alleviated generalized variable structure control for experimental robot manipulators

In this paper a chattering alleviation and experimental performance comparison of two variable structure approaches for a robot manipulator are presented. First the classical variable structure (CVS) control that is based on the equivalent control method and whose design methodology is discussed in the context of differential geometry is presented. Second, the proposed generalized variable structure (GVS) which uses the differential algebra tools for control design is discussed and developed. In virtue of the well-known variable structure robustness, a sufficient approximate linear models are obtained for each robot axis by identification which are then utilized to design the proposed controllers. The controllers implementation are initially conducted in simulations and then on the robot system. Thus, the experimental results have confirmed the conclusions of the simulation step which have proved clearly the benefit of the proposed GVS approach in terms of chattering alleviation and performance improvements. In the tracking mode, experimental results for the GVS are provided to show the insensitivity of the controller against parameter variations and rejection of external disturbances