Sliding mode control for a class of non-affine nonlinear systems Original Research Article

The objective of this paper is to present a sliding mode control (SMC) technique for a class of nonlinear and control non-affine systems. A rotor supported by a pair of magnetic bearings is introduced as a nonlinear system which is designed as a sequence of linear time-varying (LTV) systems and iterated for each time. The sliding surface is designed for each iterated LTV system by using the time response of the previous iteration. The surface parameters are selected so that the poles of reduced order LTV system remain on the left-hand side of the complex plane. It is shown that the response of LTV approximations converges to the nonlinear system’s response which is validated by using the non-affine nonlinear dynamical equations of rotor-active magnetic bearing system.