Adaptive Prescribed-Time Tracking Control for Strict-Feedback Nonlinear Systems: A Novel Full Errors Approach

In this article, a novel full errors prescribed-time tracking control issue is studied for strict-feedback nonlinear systems with compounded perturbations and input constraints. The conventional error constraint methods that require adjusting 2n design parameters to ensure all errors enter the specified accuracy within a preassigned settling time greatly increase the complexity of controller design. By blending the modified shifting function and the barrier Lyapunov function, the presented control scheme only needs to adjust n parameters to achieve full errors prescribed-time convergence. Besides, the dead-zone input is divided into a linear term and an interference-like term. A disturbance observer is devised to estimate and compensate the compounded perturbations, including external perturbations, fuzzy approximation errors and interference-like term, which significantly enhances the accuracy of the feedback compensation mechanism. It is proved that all signals of the closed-loop system are bounded. Finally, the availability of the proposed control strategy is testified via a simulation example of an RLC circuit.