A Novel Tracking Control Algorithm With Finite-Time Disturbance Observer for a Class of Second-Order Nonlinear Systems and its Applications

Anh Tuan Vo,Hee-Jun Kang,Thanh Nguyen Truong

doi:10.1109/access.2021.3060381

Abstract

This study aims to build a novel tracking control algorithm using a finite-time disturbance observer which obtains fast convergence within a predetermined amount of time and strong stability for a class of second-order nonlinear systems. Firstly, a nonlinear sliding mode manifold with fast finite-time convergence is introduced. Then, according to the designed manifold for the guarantee of finite-time convergence and robustness stabilization, a nonlinear control algorithm based on theory of finite-time control is developed. Specifically, the information of the lumped uncertainty was achieved by a new finite-time Disturbance Observer (DO). Thanks to the synthetic advantages of the above techniques, the designed controller marked with powerful features including a practical design, fast convergence rate, high precision, a convergence of the control errors in finite-time, along with impressive small chattering in the control actions. Furthermore, the control proposal also eliminates the necessity of the upper boundary of the uncertainties affecting the system and its finite settling time can be estimated in advance by designating the appropriate design parameters. The finite-time stability of the proposed DO, sliding surface, and control algorithm has been fully confirmed by Lyapunov principle. Trajectory tracking simulation for a 3-DOF manipulator and trajectory tracking experiment for a Maglev System (MLS) has been performed under different operating conditions using MATLAB/SIMULINK to testify the effectiveness and feasibility of the suggested strategy.

Highlights

T HE nature of all physical systems is nonlinear
This study aims to build a novel tracking control algorithm using a finite-time disturbance observer which obtains fast convergence within a predetermined amount of time and strong stability for a class of second-order nonlinear systems
5) The Finite-time stability and robustness of the proposed Disturbance Observer (DO), sliding surface, and control algorithm has been fully confirmed by Lyapunov principle, simulation for a 3-DOF manipulator, and trajectory tracking experiment for an Maglev System (MLS) under different operating conditions

Summary

Introduction

T HE nature of all physical systems is nonlinear. Maglev Systems (MLSs) have unstable characteristics and are described by high nonlinear differential equations, robot manipulators with the presence of friction at the joint actuator, uncertain dynamics, noise sensor, or external disturbances, and many other nonlinear systems in technology. Each nonlinear system is widely applied in different fields. Robots are required to operate reliably, safely, with high performance. Rocket-guiding projects, frictionless bearings, magnetic bearings, high-speed trains, wafer distribution systems, contactless melting, vibration isolation systems, microrobotics, gyroscopes, and so on. The applications of other nonlinear systems such as helicopters, underwater vehicles, drones, inverted pendulums, etc. Developing advanced solutions to increase safety, quality, and reliability for nonlinear systems is a challenge for researchers.

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Conclusion