Predefined-Time Exact Tracking for Nonstrict Feedback Nonlinear Systems: A Novel Switching Feedback Gain Method
提出一种自适应预定义时间控制方案，通过切换反馈增益方法处理未知非线性和故障，确保在预定义时间内实现零跟踪误差，适用于非严格反馈非线性系统。
This article proposes a novel adaptive predefined-time control scheme that guarantees global prescribed performance and exact tracking for a class of uncertain nonlinear systems characterized by nonstrict feedback dynamics, actuator faults, external disturbances, and sensor faults. Anovel switching feedback gain method is introduced to simultaneously handle unknown nonlinearities, disturbances, and actuator faults, while a tan-type error transformation and a new Lyapunov-like energy function are designed to ensure that all signals in the closed-loop systems remain globally bounded without requiring knowledge of control coefficients. In contrast to existing finite-time or asymptotic tracking control strategies, the proposed method ensures exact convergence to zero tracking error within a predefined time—independent of initial conditions—while strictly maintaining prescribed transient performance bounds. Simulation results validate the effectiveness of the proposed approach and its superiority over conventional methods, demonstrating faster convergence and smaller overshoot, thereby establishing a new benchmark for high-precision control of nonstrict feedback systems.