Prescribed‐time observer‐based output feedback control for nonlinear systems with full‐state constraints

Abstract This paper concentrates on the output feedback control problem of a nonlinear system with asymmetric full‐state constraints. Firstly, a novel prescribed‐time (PT) switched reduced‐order observer is proposed for nonlinear system with nonvanishing disturbance. Moreover, for both disturbance‐free and asymptotically vanishing disturbance cases, the proposed PT switched reduced‐order observer guarantees exact PT estimation. Thus, the full‐state constraints problem of the original system is converted into how to design the controller such that the states of the observer are constrained. Subsequently, a low‐computation control law is constructed to directly constrain the states rather than impose constraints on errors. Then, it is guaranteed that all signals in the closed‐loop system are bounded and asymmetric state constraints are maintained after the PT. Finally, the effectiveness of the main result is illustrated by the single‐link robot system.