Approximation-free control for unknown systems with performance and input constraints

This paper addresses the problem of tracking control for an unknown nonlinear system with time-varying bounded disturbance subjected to prescribed Performance and Input Constraints (PIC). Since simultaneous prescription of PIC involves a trade-off, we propose an analytical feasibility condition to prescribe feasible PIC which also yields feasible initial state space as corollary results. Additionally, an approximation-free controller is proposed to guarantee that the tracking performance adheres to the prescribed PIC. The effectiveness of the proposed approach is demonstrated through numerical examples.