Adaptive constrained sliding mode control of uncertain nonlinear fractional-order input affine systems

Abstract

This paper addresses asymptotic stabilization of uncertain nonlinear fractional-order systems with bounded inputs in the presence of model uncertainties and external disturbances. To develop the idea, it is assumed that the upper bound of perturbations is a nonlinear function of the pseudostates norm in which its coefficients are unknown and are obtained via proposed adaptive laws. The main contribution of this paper is to develop a new bounded fractional-order chattering free adaptive sliding mode control in which the system states converge to the sliding surface at a predefined finite time. The stability of the closed-loop system with the proposed control scheme is guaranteed by the Lyapunov theory. Furthermore, for more clarification, a comparison with the classical integer-order case is also presented; finally, some practical simulation results are provided to show the effectiveness of the proposed control algorithm.