Adaptive variable structure control of uncertain systems containing unknown gain reduction tolerance

In this paper, an adaptive variable structure controller (AVSC) is presented for a class of uncertain systems subjected to input nonlinearities. Using an adaptive technique, an AVSC is then proposed to ensure the asymptotical convergence of the switching quantity even without involving the bound of the gain reduction tolerance. On the switching surface, the investigated uncertain system still bears the insensitivity to the uncertainties and disturbances as the systems with linear input. An illustrative example is given to demonstrate the effectiveness of the proposed AVSC design method.