Finite-Time Disturbance Rejection Control for Rigid Spacecraft Attitude Set Stabilization With Actuator Saturation

Rigid spacecraft plays significant roles in future space exploration. In this article, a continuous bounded switching solution is studied for the finite-time attitude stabilization control of the spacecraft system considering the actuator saturation problem. First, with the adoption of the super-twisting disturbance observer, the lumped disturbance within the spacecraft dynamics can be accurately estimated. Then, combining with disturbance estimations, a composite switching control approach is proposed, which is transitioned from discontinuous relay polynomial form to continuous nonsmooth form. With the proposed controller, spacecraft attitude is finite-time set stable even with multisource disturbances. Moreover, the actuator saturation problem will not be violated and a bounded control input amplitude is obtained. Finally, various simulation cases are characterized by stronger disturbance rejection ability and higher attitude tracking accuracy as compared with existing solutions.