Rigid-Body Attitude Tracking Control Under Actuator Faults and Angular Velocity Constraints

The problem of rigid-body attitude tracking is examined for the case that there exist actuator faults and angular velocity constraints during the attitude maneuver. With a hyperbolic tangent function as input signal, a first-order command filter is proposed to generate a virtual velocity error command for the angular velocity tracking error to follow. Then, an adaptive fault-tolerant controller based on the command filter is designed without requiring information of actuator fault, moment of inertia, and external disturbances. Through Lyapunov stability analysis, it is shown that the control law guarantees that the desired attitude is tracked even in the presence of actuator faults and external disturbances. Finally, simulations are conducted on a rigid spacecraft and results demonstrate the effectiveness of the proposed strategy.