Attitude stability control of capturing spacecraft without angular velocity

The main problem addressed is the attitude tracking control of rigid spacecraft without angular velocity measurement in the process of capturing non-cooperation target, angular velocity observer and adaptive attitude stability controller have designed to deal with this problem. An adaptive PID attitude controller is proposed, in which, the composite disturbance combined with inertia perturbance and external disturbance, is compensated by adaptive estimation, an angular velocity observer had been designed based on the adaptive PID controller, then, a novel modified PID controller have been obtained, which will only need attitude measurements, Lyapunov theory analysis verified the close-loop system is global asymptotically stability with the modified PID controller without angular velocity measurements. Finally, a variable gain replaced the constant gain to reduce the control magnitude. Typical numerical simulation has validated the variable gain controller have high-precision tracking ability and strong robustness of the closed-loop system.