Fault Tolerant Control Of Multi-UAV Formation Based On Control Reconfiguration

With the continuous improvement of control theory and with the maturity of multi-agent theory,multiple quadrotors can communicate with each other,multiple quadrotor UAVs can accomplish tasks by cooperating with each other with high efficiency.However,the faults of multiple UAVs often have an indestructible impact on the whole system,which affects the quality of flight and the progress of task completion.Therefore,it is of great significance for the research of multi-UAV fault-tolerant control methods.In this paper,the quadrotor is taken as the research object,and its mathematical model is established.The research of this paper mainly consists of the following parts:Firstly,for multi-UAV leader-follower formation,virtual actuators are used to hide faults and achieve fault tolerance.The nominal controller is established for healthy UAV,and the sliding mode formation control is established for UAV formation model to achieve system stability.Considering the partial failure of a single UAV actuator,the virtual actuator is used to make the equipment with the virtual actuator the same as the normal condition,so as to achieve fault tolerance.The simulation compares the sliding mode formation method with the adaptive sliding mode formation method,and the effect of the adaptive sliding mode formation is better.Secondly,based on the three-dimensional distributed formation of quadrotor,a new method of adaptive fault concealment module estimation is used.Compared with the third chapter and the traditional fault concealment method,the method of adaptive fault concealment module estimation is used to realize fault tolerance considering the unknown value of the actuator failure factor.Firstly,the sliding mode distributed formation control law is designed for the position and attitude subsystems of the fault-free quadrotor system,so that the system can maintain consistency and achieve the desired position under normal conditions.Then considering the location fault,in order to avoid the impact of the estimated value of the fault on the health system,the state observer is used to detect whether the fault occurs or not,and when the residual signal exceeds the threshold,the fault of the quadrotor is determined.If the fault is detected,a module based on adaptive fault estimation is added to hide the fault to realize fault-tolerant control.It is not necessary to know the value of partial failure factor of the actuator in advance.Thirdly,based on the three-dimensional distributed formation of quadrotor,considering the convergence of formation in finite time,the formation of quadrotor,can be restored to the desired position in finite time by terminal sliding mode method,and the finite-time convergence of UAV formation can be realized by terminal sliding mode after failure,which can make the formation quickly converge to the desired position and reduce the impact time of failure on formation flying.