Adaptive nonsingular fixed-time sliding mode control for uncertain robotic manipulators under actuator saturation. (April 2022)

• Record Type: Journal Article
• Authors: Sai, Huayang; Xu, Zhenbang; He, Shuai; Zhang, Enyang; Zhu, Lin
• Is Part Of: ISA transactions. Volume 123(2022)
• Page Start: 46
• Page End: 60
• Publication Date: 2022-04
• Subjects: Fixed-time sliding mode control -- Actuator saturation -- Robotic manipulator -- Uncertainties and disturbances; Engineering instruments -- Periodicals; Engineering instruments; Periodicals; Electronic journals; 629.805
• DOI: 10.1016/j.isatra.2021.05.011
• Languages: English
• ISSNs: 0019-0578

Abstract

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. Graphical abstract: Highlights: A novel nonsingular approximate fixed-time sliding mode control is presented. An adaptive law is introduced for the nonsingular fixed-time sliding mode control. An actuator saturation compensator is designed to compensate for actuator saturation. It is shown that the bound of the lumped uncertainty is unnecessary. Precise motion tracking performance and fast singularity-free transients are achieved.