Guaranteed Cost Attitude Tracking Control for Uncertain Quadrotor Unmanned Aerial Vehicle Under Safety Constraints

In this paper, guaranteed cost attitude tracking control for uncertain quadrotor unmanned aerial vehicle (QUAV) under safety constraints is studied. First, an augmented system is constructed by the tracking error system and reference system. This transformation aims to convert the tracking control problem into a stabilization control problem. Then, control barrier function and disturbance attenuation function are designed to characterize the violations of safety constraints and tolerance of uncertain disturbances, and they are incorporated into the reward function as penalty items. Based on the modified reward function, the problem is simplified as the optimal regulation problem of the nominal augmented system, and a new Hamilton-Jacobi-Bellman equation is developed. Finally, critic-only reinforcement learning algorithm with a concurrent learning technique is employed to solve the Hamilton-Jacobi-Bellman equation and obtain the optimal controller. The proposed algorithm can not only ensure the reward function within an upper bound in the presence of uncertain disturbances, but also enforce safety constraints. The performance of the algorithm is evaluated by the numerical simulation.