Variable structure control with time-varying boundary layer for robot manipulator

Variable structure control (VSC) with time-varying boundary layer for robot manipulator is proposed. Chattering is a common problem in VSC implementation. It is generally reduced using a boundary layer concept which has a trade-off between chattering and tracking error. Thus, it would be better if boundary layer can adapt itself to an appropriate value as proposed by Bekit et al. (1998). However, the method requires a linear parametrized model of robot which is difficult to find for multiple-joint robot arm. In this paper, time-varying boundary layer is developed so that the model is no longer needed. As shown in the simulation results, the proposed method can reduce chattering and still has a small error at steady state