Practical nonovershooting tracking control with prescribed-time for nonlinear output-feedback systems

This study addresses the problem of practical nonovershooting tracking control for n -th order nonlinear systems with unmeasurable states. The objective is to achieve practical nonovershooting performance within a user-prescribed time, ensuring that the system overshoot remains below an arbitrarily small constant. First, a state observer is designed to estimate the unavailable states. A prescribed-time stability criterion is then introduced to provide a theoretical foundation. Within the backstepping framework, a controller is subsequently devised to guarantee both prescribed-time stability and the desired practical nonovershooting performance. When complete elimination of overshoot is infeasible, the overshoot can be rendered arbitrarily low through parameter tuning, thereby balancing performance with practical applicability. The gain algorithm proposed herein ensures the stability of the closed-loop system and drives the system states to zero within the prescribed-time. The efficacy of the control strategy is validated through simulations of a single-link robotic manipulator. The results demonstrate that the output tracks the reference signal within the prescribed-time without excessive overshoot, while all control signals remain smooth and bounded, confirming the controller”s practical viability.