Sliding Mode Control of the RTAC System

In this paper, a sliding mode control (SMC) scheme is presented for the rotational/translational actuator (RTAC) system, which is proposed without linearizing or approximating the dynamics. Different from the existing control methods, external disturbances are taken into consideration in this paper. In particular, after some model transformations, a novel dynamic equation with a cascade form of the underactuated RTAC system is obtained. Then, based on the backstepping technique, a desired control variable is proposed to control the first subsystem and a corresponding deviation-based subsystem is constructed. On the basis of the introduced deviation-based subsystem, a sliding mode controller is proposed straightforwardly. Simulation results including a comparative study are included to examine the control performance of the presented scheme.