Discrete-Time Super-Twisting Guidance Law with Actuator Faults Consideration

This paper proposes a robust fault-tolerant guidance law against unknown maneuvering targets based on discrete-time sliding mode control theory. To address this problem, a time-delay observer is designed to estimate the lumped disturbance, which includes target maneuver as well as actuator faults. A robust discrete-time guidance law is then synthesized based on the discrete-time super-twisting algorithm. Due to the principle of the super-twisting algorithm, the presented guidance law is a naturally chattering-free formulation. Detailed stability analysis shows that the line-of-sight angular rate under the proposed guidance law can be stabilized in a small region around zero. Simulation results are also provided to verify the effectiveness of the proposed approach.