A Novel Prescribed-Time Control Approach Under Unknown Control Gain and Mismatched Disturbance
针对一类具有未知控制系数和不匹配扰动的非线性系统，提出了一种预设时间输出反馈控制器，通过结合Nussbaum函数实现预设时间稳定，并证明系统输出和观测器误差在预设时间内收敛到零。
In this article, a prescribed-time output feedback controller is proposed for a class of uncertain nonlinear systems with unknown control coefficients and mismatched nonvanishing disturbances. Both unknown control coefficients and mismatched disturbances are tricky to address by the existing prescribed-time output feedback control frameworks. Differently, a novel prescribed-time control criterion in conjunction with Nussbaum functions is proposed, and prescribed-time stability is achieved. Furthermore, design methods for a state observer and a prescribed-time output feedback controller are developed. With the proposed control design, both the system output and observer errors are rigorously proved to converge to zero within a prescribed time. Moreover, the unified prescribed performance (UPP) of the system output and the satisfaction of output constraints are simultaneously achieved. Numerical simulations and experiments are provided to illustrate the effectiveness of the proposed control design.