Attitude fault-tolerant control method of launch vehicle based on composite learning and fixed time synchronization

In this paper, an attitude fault-tolerant control method based on composite learning and fixed time convergence is designed to solve the attitude control problem of a launch vehicle with actuator failure and external interference. Firstly, the attitude control model and fault model of the launch vehicle are established to describe the attitude motion characteristics of the system in the case of fault and disturbance. Then, the convergence strategy of time synchronization is introduced, the fixed time synchronization fault estimator and controller are designed, and the stability is proved. By compensating for the additional disturbance with a disturbance estimator, a composite learning algorithm using tracking error and prediction error is constructed to deal with the influence of external disturbance on the control system. Compared with the traditional finite time control method, the time synchronization control strategy proposed in this paper can ensure that the attitude error of the system converges simultaneously in a fixed time, which can effectively enhance the overall response of the control system. Finally, the attitude tracking effect and fault tolerance of the proposed control strategy are verified by simulation.