OUTPUT FEEDBACK ATTITUDE CONTROL FOR RIGID SPACECRAFT UNDER ATTITUDE CONSTRAINTS

An output feedback control law is proposed in this paper for spacecraft attitude reorientation task. Although attitude maneuver has been widely investigated and obtained significant results, it is still challenging when considering attitude pointing constraints and lacking the information of angular velocity. Firstly, potential function is introduced to tackle attitude pointing constraints. Then, by jointly designing sign function and potential function, the anti-unwinding performance can also be achieved. Furthermore, the relevant information of angular velocity is obtained by utilizing first-order passive filter with the attitude error quaternion. Moreover, by properly selecting candidate Lyapunov function, the feasibility of attitude constraints can be rigorously proved under the proposed control law, while the stability of the system can be guaranteed without signal of angular velocity and information of inertia matrix. A numerical example is carried out to demonstrate the effectiveness of the proposed method.