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Adaptive Fault-Tolerant Control of Mobile Robots with Fractional-Order Exponential Super-Twisting Sliding Mode

Authors :
Hao Wu
Shuting Wang
Yuanlong Xie
Hu Li
Source :
Fractal and Fractional, Vol 8, Iss 10, p 612 (2024)
Publication Year :
2024
Publisher :
MDPI AG, 2024.

Abstract

Industrial mobile robots easily experience actuator loss of some effectiveness and additive bias faults due to the working scenarios, resulting in unexpected performance degradation. This article proposes a novel adaptive fault-tolerant control (FTC) strategy for nonholonomic mobile robot systems subject to simultaneous actuator lock-in-place (LIP) and partial loss-of-effectiveness (LOE) faults. First, a nominal fractional-order sliding mode controller based on the designed exponential super-twisting reaching law is investigated to reduce the reaching phase time and eliminate the chattering. To address the time-varying LIP faults and uncertainties, a novel barrier function (BF)-based gain is explored to assist the super-twisting law. An estimator is designed to estimate the lower bound of the time-varying partial LOE fault coefficients, thus without requiring the boundary information of faults that is commonly requested in traditional FTC schemes. Combined with the nominal controller clubbed with BF and estimator-based LOE fault compensation term, the fault-tolerant controller is finally constructed. The proposed FTC scheme achieves fast convergence and the sliding variables can be confined in a predetermined neighborhood of the sliding manifold under actuator faults. The results show that the proposed controller has superior tracking performance under faulty conditions compared with other state-of-the-art adaptive FTC approaches.

Details

Language :
English
ISSN :
25043110
Volume :
8
Issue :
10
Database :
Directory of Open Access Journals
Journal :
Fractal and Fractional
Publication Type :
Academic Journal
Accession number :
edsdoj.83d54a016f14e06b8b76a0362dfd5cb
Document Type :
article
Full Text :
https://doi.org/10.3390/fractalfract8100612