| With the application field of quadrotor continued to spread, the requirement of safety and reliability to quadrotor are getting higher and higher, so more and more scientific research institutions began to study the fault-tolerant control of quadrotor. Quadrotor are flying long time in harsh environments, the actuator is relatively easy to aging, and will be damaged due to collision, so the actuator of quadrotor is the source of fault.This paper for the actuator failure of quadrotor, proposed a robust fault-tolerant control method which is combines delay control and backstepping control method. The method succeed the advantage of backstepping control method, at the same time, a integral element is introduced in the backstepping method is used to eliminate the steady state error.With the time delay control, unknown actuator faults are estimated by using one-step previous state information and canceled out by the estimated values, so that the fault detection and isolation mechanism is not involved.Both analytical and numerical results are presented to demonstrate the theoretical and practical merits of this approach.The method that combines the time delay control technique and backstepping control method, when there is a failure of the actuator, the system response is slow.And the weak robustness of backstepping control method to the parameter perturbation problem.Therefore, in the paper,the sliding mode control and time delay control combined to solve the actuator fault problem.Because there are symbolic function of sliding mode control reaching law, will make the system violent shaking. Therefore, this thesis introduces a new reaching law which is based on PID, with the continuous control input instead of discontinuous switching input. By comparing the simulation results,the the robust fault tolerant control method that combined the modified sliding mode control method and time delay control can effectively solve the more serious actuator problem and model parameters uncertainty. |
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