Constrained Attitude Control of Over-actuated Spacecraft Subject to Instrument Pointing Direction Deviation

In this paper, the attitude reorientation problem for over-actuated rigid spacecraft subject to multiple attitude constrained zones is studied. Considering the pointing direction deviation of sensitive equipments and constraint operating set, a robust potential function for attitude constrained zones is proposed and is further leveraged to design a high-level attitude controller, which achieves asymptotic convergence of attitude reorientation error while avoiding attitude constrained zones. Moreover, to distribute the desired control torque from high-level controller to each actuator dynamically, a finite-time adaptive control allocation is developed, resulting in an improved allocation error convergence rate when compared with existing control allocation methods. Simulation examples involving a rest-to-rest attitude maneuver are given to demonstrate the effectiveness of the proposed overall control strategy.