Sliding mode control for robot manipulators using time-varying switching gain and boundary layer

A methodology of smoothing the control output of a sliding mode controller for a robot manipulator is proposed. The method uses a time-varying switching gain and a time-varying boundary layer, which is a function of the tracking error is used to reduce the undesirable chattering while keeping the robust characteristic that rejects system uncertainties. Simulation results show that the proposed controller gives a good system performance in the face of uncertain system parameters and external disturbances