Integral backstepping based robust integral sliding mode control of underactuated nonlinear electromechanical systems

Abstract

This paper presents an integral backstepping integral sliding mode (IBISMC) based robust control scheme to asymptotically stabilize a class of underactuated nonlinear electromechanical systems (UNEMSs) at desired equilibria. Prior to control design, the dynamic model of the aforesaid class is first transformed into a regular form that is more convenient for control design. This transformation subdivides the overall system's dynamics into a series cascaded form which are termed as internal dynamics and visible dynamics blocks while proceeding from the left side. The output of the internal dynamics (first block), is controlled via the virtual control technique whereas, in the visible dynamics (second block), the actual control law is designed by integral sliding mode control (ISMC) technique to track the output of the first block. In this way, the overall system is controlled via a robust nonlinear control algorithm. The global asymptotic stability of each step is proved via Lyapunov candidate function whereas the enforcement of ISMC from the very start is ensured in a theorem. The applicability and benefits of this strategy are demonstrated via the simulation results of a cart-pendulum system. The results of our strategy are also compared with the standard literature results to highlight the appealing nature of the proposed strategy for such class.