High Dynamic Staring Tracking Control Method for Non-coplanar Orbital Rendezvous Spacecraft Based on Fast Terminal Sliding Mode Controller

Aiming at the mission of space situational awareness spacecraft close reconnaissance to non-cooperative target, high dynamic staring tracking control of situational awareness service spacecraft and target spacecraft during non-coplanar orbital rendezvous is investigated in this paper. Different from the traditional attitude maneuver and ground target tracking, the high dynamic characteristics of the non-coplanar orbital rendezvous staring tracking require greater agility, greater control torque and higher accuracy for the service spacecraft, which is a challenge for the attitude control system. The hybrid actuator configuration consisting of Reaction Wheel (RW) and thruster is introduced. And an online dynamic control allocation strategy is designed, accordingly. Considering the system output error and environment disturbance, a fast terminal sliding mode (FTSM) controller is proposed to avoid the RW saturation and ensure the attitude stability at switching time. Because of the unified controller, the output torque at the actuator switching time will not change dramatically, and the angular velocity jump can be obviously suppressed. Attitude stability analysis shows that the controller can make the spacecraft converge in finite time, track the high dynamic staring target continuously, and ensure the stability of the control system. Numerical simulation results are provided to demonstrate the performance of the proposed controller.