Nonlinear optimal tracking control in combination with sliding modes: Application to the Pendubot

This paper proposes a robust control scheme based on the combination of nonlinear optimal tracking control with sliding modes for a class of nonlinear systems, which can be represented into the so-called regular form. Firstly, an optimal controller is proposed to define an optimal sliding surface, and secondly, the surface is used for synthesizing a super-twisting controller (a second-order sliding mode technique). This combination takes the advantages of optimality and robustness of both control methodologies, respectively, resulting in an optimal sliding mode controller, which constitutes the main contribution of this paper. The effectiveness of the control methodology is illustrated via simulations for the Pendubot, which is a nonlinear and non-minimum phase system.