Adaptive critic control for spacecraft attitude tracking with appointed-time convergence

This paper investigates the appointed-time prescribed performance attitude tracking control problem of a rigid spacecraft using the adaptive critic control. Firstly, the error transformation technique is utilized to convert the system with the prescribed performance constraint into an equivalent unconstraint optimal control problem. Then in the framework of adaptive critics, the critic-only architecture is built to solve the Hamilton-Jacobi-Bellman equations associated with these solutions. A rigorous mathematical stability proof is given. Finally, numerical simulations are presented to demonstrate the effectiveness and robustness of the proposed controller.