Tracking Control for High-order Fully Actuated System with Input Constraints by Explicit Reference Governor

This paper studies the tracking control problem of high-order fully actuated system subject to input constraints. Since there exist input constraints, an inappropriate reference signal being tracked may cause actuator saturation and further cause system instability. For solving the problem, we firstly design a generalized proportional differential controller to ensure the stability of the closed-loop system without input constraints. Then, an explicit reference governor is constructed to modify the reference signal such that the applied reference signal never exceeds the saturation limits, and the equilibrium of the resulting closed-loop system is globally asymptotically stable. Furthermore, we prove that the applied reference will converge to the original reference as much as possible. Therefore, the system output finally converges to the original reference by tracking the applied reference. A numerical example demonstrates the validity of the proposed method in this paper.