Adaptive Practical Fixed-Time Control for a Class of Nonlinear Systems with Input Saturation

In this paper, the problem of adaptive practical fixed-time control is investigated for a class of uncertain nonlinear systems with input saturation. A fixed-time command filter is introduced to solve the problem of "explosion of complexity", and the fractional order error compensation mechanism is used to eliminate the effect of filter error. To address the input saturation, a novel fixed-time auxiliary system is constructed. By combining the novel command filter and backstepping design method, a fixed-time state-feedback controller is designed. It is proved that the output tracking error converges to a region of zero within fixed time. A main advantage is that the convergence time is predefined without dependence on initial states. Finally, a numerical example is provided to show the effectiveness of the proposed control scheme.