Adaptive nonsingular fixed-time sliding mode control for uncertain robotic manipulators under actuator saturation

Huayang Sai; Zhenbang Xu; Shuai He; Enyang Zhang; Lin Zhu

doi:10.1016/j.isatra.2021.05.011

Adaptive nonsingular fixed-time sliding mode control for uncertain robotic manipulators under actuator saturation

ISA Trans. 2022 Apr:123:46-60. doi: 10.1016/j.isatra.2021.05.011. Epub 2021 May 25.

Authors

Huayang Sai¹, Zhenbang Xu², Shuai He³, Enyang Zhang³, Lin Zhu⁴

Affiliations

¹ CAS Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² CAS Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: xuzhenbang@ciomp.ac.cn.
³ CAS Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
⁴ CAS Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China; University of Chinese Academy of Sciences, Beijing 100049, China; Institute of Applied Physics, Friedrich-Schiller-University Jena, Max-Wien-Platz 1, 07743 Jena, Germany.

PMID: 34238519
DOI: 10.1016/j.isatra.2021.05.011

Abstract

This paper describes an adaptive nonsingular fixed-time sliding mode control (ANFSMC) scheme under actuator saturation that can track the trajectory of a robotic manipulator under external disturbances and inertia uncertainties. First, a novel NFSMC that offers rapid convergence and avoids singularities is proposed for ensuring robotic manipulators global approximate fixed-time convergence. An ANFSMC is then developed for which the bound of the coupling uncertainty is not necessary to know in advance. The controller exhibits small absolute tracking errors and consumes little energy. An actuator saturation compensator is designed and shown to minimize the chattering of the system while accelerating the trajectory tracking. The proposed schemes are analyzed using Lyapunov stability theory, and their effectiveness and superiority are demonstrated through numerical simulations.

Keywords: Actuator saturation; Fixed-time sliding mode control; Robotic manipulator; Uncertainties and disturbances.