Continuous Robust Control Based on Fixed-Time Super-Twisting Disturbance Observer
针对一类不确定非线性系统，设计了固定时间超螺旋扰动观测器和连续固定时间控制方案，使误差在预定时间内收敛到零，且控制信号连续无抖振。
This article investigates fixed-time control methods for a class of uncertain nonlinear systems. A novel fixed-time super-twisting (FXST) disturbance observer has been designed to accurately estimate the imposed perturbations on the system in the sense of fixed-time stability without being affected by initial conditions. Then, based on the achieved estimation from the proposed FXST disturbance observer, a continuous fixed-time control (CFXC) scheme for a class of uncertain nonlinear systems has been designed. The control protocols and estimation rules are continuous without the discontinuity and chattering issue so that the errors can be converged to the origin within a predefined fixed time. Furthermore, by means of an improved estimation algorithm and proposed integral structure, some limitations on the controller and observer have been relaxed. Finally, the efficiency of the designed methods has been demonstrated via some simulation results.