Finite-Time Fault Estimator Based Fault-Tolerance Control for a Surface Vehicle With Input Saturations

• Published in: IEEE transactions on industrial informatics Vol. 16; no. 2; pp. 1172 - 1181
• Main Authors: Wang, Ning, Deng, Zhongchao
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.02.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Actuators; Controllers; Error analysis; Fault tolerance; Fault tolerant systems; Fault-tolerance control (FTC); Faults; finite-time fault estimator (FFE); Informatics; input saturation; surface vehicle (SV); Surface vehicles; System dynamics; Tracking errors; Tracking problem; Trajectory control; Uncertainty; Vehicle dynamics
• ISSN: 1551-3203; 1941-0050
• DOI: 10.1109/TII.2019.2930471

In this article, in the presence of unknown actuator faults, input saturations, and complete unknowns including both internal dynamics and external disturbances, exact trajectory-tracking problem of a surface vehicle (SV) is solved by creating a finite-time fault estimator based fault-tolerance control (FFE-FTC) scheme. By virtue of input saturations, smoothly saturated controls are separated from input nonlinearities including unknown faults, thereby leaving faults-mixed unknowns be exactly observed by a finite-time fault estimator (FFE). By defining an integral sliding-mode (ISM) manifold and deriving affine controls with unknown gains from smooth saturations, Nussbaum technique is deployed to synthesize a uniformly adaptive finite-time controller working in a large range outside input saturations. Within the close range where saturations are removed, an ISM-based nonsmooth controller with finite-time auxiliary compensation dynamics is devised to finely stick tracking errors to the origin. Intuitively, large- and close-range control actions are triggered by measuring the ISM error, thereby contributing to the entire FFE-FTC scheme, which achieves exact fault-tolerance and unknown rejection under input saturations. Lyapunov and nonsmooth syntheses prove that the closed-loop FFE-FTC system is globally finite-time stable. Simulation results and comparisons on a prototype SV demonstrate remarkable performance in terms of feasibly saturated controls and exact trajectory-tracking, simultaneously.