Research On Fault Tolerant Control Strategy Of Six-Rotor UAV System

Due to the characteristics of small size and high flexibility of Unmanned Aerial Vehicle(UAV),it is more and more popular in people's life.The six-rotor UAV is one of the typical representative UAV,which has better stability and load capacity than the four-rotor UAV.With the wide application of UAV,more and more problems are appeared when working.Therefore,people put forward higher requirements for the reliability and stability of UAV,and many scholars have carried out in-depth research on the fault tolerant control strategies of UAV.This thesis takes six-rotor UAV as the research object,and it is mainly about the effectiveness of the fault tolerant control method of switching system when the actuator of the six-rotor UAV actuator fault.Firstly,the importance of studying UAV system is explained in depth,the study of the UAV at home and abroad is reviewed,and the fault diagnosis and fault tolerant technology are briefly summarized.According to the hardware structure and flight principle of the six-rotor UAV and Newton-Euler's law,the attitude angle equation and the position coupling equation of the six-rotor UAV are established and simplified.And the model after the failure of the actuator is described mathematically.Secondly,the working condition of the six-rotor UAV are divided into three categories,namely;the working state in normal conditions;the working state after partial efficiency loss of the actuator and the working state when something is wrong with single wing rotor.The sliding mode observer for a six-rotor UAV system is designed,by which the fault information is evaluated,so the information matrix is obtained.Thirdly,the controllers are designed according to three working states.The working state under normal conditions,the method of sliding mode variable structure control makes the six-rotor UAV system perfectly realize the tracking tasks of desired attitude and desired trajectory.When the failure of partial efficiency loss of the actuator occurs,the feedback controller method is adopted,the tracking tasks of attitude desired and trajectory expectation after the failure of partial efficiency loss of the actuator are completed.The backstepping control method is designed to deal with the attitude control and simple straight-line tracking task when there is matters with the single wing rotor.Fourthly,the thesis sets the three states as three subsystems,combined with the fault information matrix obtained by the designed sliding mode observer,based on the fault tolerant control method of switching system,a fault tolerant control strategy for six-rotor UAV actuator is designed.Through the emulation proof of fault tolerant strategy,it can be seen that the fault tolerant controller designed in this paper has good fault tolerant effect,and can make sufficient compensation after the failure of partial efficiency loss of the actuator,and make the system stable in a short time after the failure of single wing rotor damage.Finally,the thesis is summarized,and the subsequent research questions are explained and arranged briefly.