Design and Stability Analysis of Non-smooth Integral Sliding Surface for Coupled-Tank System with Matching/Non-matching Disturbance

This paper examine the challenges posed by conventional sliding mode design in the presence of matching/nonmatching disturbances. Previously designed approaches have proven inadequate in offering an efficient and straightforward solution to non-matching disturbances. To overcome this, a novel sliding mode control strategy centered on a non-smooth integral sliding manifold is introduced. The newly proposed sliding manifold possesses two crucial characteristics. Firstly, it functions transform to a reduced-order disturbance observer by autonomously estimating the mismatched disturbances, eliminating the need for an additional observer design. Secondly, the system consistently initiates its operation from the sliding surface, eliminating any reaching phase dynamics. As a result, the system trajectory remains resilient to disturbances right from the outset. To validate the effectiveness of the proposed method, it is simulated for a coupled tank system.