Composite anti-disturbance safety control for on-orbit inspection of spacecraft

This paper addresses the anti-disturbance safety control problem in spacecraft inspection missions, considering multiple positional obstacle constraints and attitude restrictions, both forbidden and mandatory, with logical relationships. To address this challenge, a novel Composite Anti-Disturbance Safety Control (CADSC) method is proposed, which combines control barrier functions with disturbance observers. The proposed CADSC framework achieves guaranteed safety control under complex constraints while explicitly addressing external disturbances and model uncertainties. First, positional obstacles are modeled using quadratic surface equations. At the same time, attitude constraints are formulated with logical operators, incorporating the interactions among star trackers, optical cameras, solar panels, and space environment vectors. Then, safe velocity and angular velocity are computed by solving Quadratic Programming (QP) problems based on the spacecraft's kinematic equations. The simplicity and disturbance-free nature of the kinematic model allow for efficient and accurate solutions to the QP problem, ensuring real-time applicability in mission-critical scenarios. Furthermore, proportional-like position and attitude controllers are developed to track the computed safe velocities. These controllers incorporate disturbance estimation techniques to compensate for external disturbances and model uncertainties, thereby enhancing the spacecraft's robustness. Finally, numerical simulations are conducted to validate the effectiveness of the proposed control strategy.