Terminal sliding mode disturbance observer based adaptive super twisting sliding mode controller design for a class of nonlinear systems

In this paper, an adaptive super twisting sliding mode controller (ASTSMC) is proposed for a class of nonlinear systems to counteract mismatched uncertainties. To estimate the unknown external disturbance efficiently, an adaptive terminal sliding mode disturbance observer (ATSMDO) is proposed. The stability of the over all closed loop system is proved by Lyapunov stability theory. To validate the proposed ATSMDO based ASTSMC, a case study of a nonlinear liquid level regulation problem is considered. Both simulation and real-time results are presented to show the effectiveness of the proposed controller than the traditional adaptive sliding mode controller (ASMC) and reported controllers in literature. From the analysis, it is observed that the proposed controller alleviates the chattering problem effectively. (C) 2020 European Control Association. Published by Elsevier Ltd. All rights reserved.

Automated summary

An adaptive super twisting sliding mode controller (ASTSMC) is proposed in this paper for a class of nonlinear systems to counteract mismatched uncertainties, with the introduction of an adaptive terminal sliding mode disturbance observer (ATSMDO) to estimate unknown external disturbances. The stability of the overall closed-loop system is proven using Lyapunov stability theory. A case study on a nonlinear liquid level regulation problem is conducted to validate the proposed controller, showing its effectiveness in alleviating chattering problems compared to traditional adaptive sliding mode controllers.