Anti-unwinding attitude control of spacecraft considering input saturation and angular velocity constraint

Aiming at the problem of simultaneous input saturation and angular velocity constraint in the attitude control process for spacecraft, a novel attitude control design method is proposed. With the asymptotic convergence of the attitude and angular velocity guaranteed first, this method also provides the maximum values of the input torque and attitude angular velocity explicitly. Via introducing a sharpness parameter, external disturbances can be well rejected. Based on that, the unwinding phenomenon caused by the redundancy of the quaternion is considered in addition, and a new set of attitude error function and vector involved, so that the designed controller could satisfy the constraints above and has the advantage of anti-unwinding. The simulation results show that both the input saturation and attitude angular velocity limits are satisfied, and the strong robustness of the system against large disturbances is achieved with the desired avoidance of the anti-unwinding phenomenon. The proposed method provides a novel idea and solution toward the attitude control problem of the spacecraft under multiple constraints and thus has great significance in application.