Continuous Full-Order Nonsingular Terminal Sliding Mode Control for Systems With Matched and Mismatched Disturbances

Xudong Du,Xing Fang,Fei Liu

doi:10.1109/access.2019.2941373

Abstract

A continuous full-order nonsingular terminal sliding mode control method is investigated for a general dynamic system subject to both matched and mismatched disturbances in this paper. Firstly, the essential dynamics of the original system is established based on the relative degree of system, where the original mismatched disturbances are turned into matched disturbances. Then, a composite control scheme based on the finite-time observer and full-order nonsingular terminal sliding mode control approach is developed to reject the lumped disturbances. Finally, some simulation results demonstrate the effectiveness of the proposed control strategy.

Highlights

External disturbances and system uncertainties almost exist in all practical engineering systems, which always lead to adverse effects on control systems
These control approaches are known as one-degree-of-freedom control schemes, which means that the requirements of control systems, e.g., tracking performance and disturbance rejection, may cannot be achieved synchronously and perfectly
In this paper, a new control scheme is developed for a general dynamic system subject to both matched and mismatched disturbances

Summary

INTRODUCTION

External disturbances and system uncertainties almost exist in all practical engineering systems, which always lead to adverse effects on control systems. Various control approaches have been developed to deal with the disturbances and uncertainties, such as H∞/H2 control [5], adaptive control [6], finite-time control [7], [8], sliding mode control [9]–[11], and so on. A new control strategy via the full-order nonsingular terminal sliding mode control approach is developed for a general dynamic system subject to both matched and mismatched disturbances. Scheme for the system to drive the output y to the origin along the full-order sliding-mode surface in finite time even in the presence of both matched and mismatched disturbances. To the best knowledge of the authors, the existing full-order terminal sliding mode control (FO-TSMC) cannot deal with these mismatched disturbances effectively. The integral chain system is only subject to matched disturbances, which means that the original mismatched disturbances are turned into matched disturbances [32]

FINITE-TIME OBSERVER

CONTROLLER DESIGN

SIMULATION RESULTS AND ANALYSIS

CONCLUSION