Predefined-Time Composite Fuzzy Adaptive Control for Flexible-Joint Manipulator System With High-Order Fully Actuated Control Approach
Huixin Jiang, Yana Yang, Changchun Hua, Xiaolei Li, Fangyao Lu
Abstract
This article focuses on the preassigned-time composite fuzzy adaptive trajectory tracking control for a class of uncertain flexible-joint manipulator (FJM) systems under high-order fully actuated (HOFA) control approach. Superior to traditional backstepping-based state-space methods, the HOFA approach applying to FJM essentially relieves the computational burden, thus enhancing the system’s operational efficiency. A noteworthy contribution of this article is the first development of a composite fuzzy adaptive control (CFAC) scheme by which all the tracking errors of uncertain system can ultimately converge to zero rather than a bound. Surpassing the traditional fuzzy control methods, the effect of parameter truth value and estimation error on the system convergence performance is essentially eliminated. By incorporating both current and historical learning data, the more precise parameter estimation can be acquired under a more practicable interval excitation (IE) condition. Further, a time-dependent function incorporated preassigned-time nonsingular integrator sliding mode (PNISM) control law is creatively proposed to not only heighten the transient-state response speed but also greatly improve the steady-state tracking accuracy. Finally, simulations and experiments are conducted to authentically corroborate the efficacy of the proposed control algorithm.