Fault-tolerant Control Of An Hexarotor UAV Rotor System

Hexarotor UAVs bring a lot of convenience to people's lives,but the crash of hexarotor UAVs has also caused huge losses to people's personal safety and property safety.In order to reduce the crash accidents of hexarotor UAVs,this paper studies the fault-tolerant control of an hexarotor UAV rotor system.The main contents of the research include1)Based on Newton's second law and Euler's dynamic equations,the dynamic model of an hexarotor UAV is established,and the nonlinear dynamic model is re-written by a linear pa-rameter varying method.Finally,the failure mode of the rotor system is analyzed and the corresponding failure model is established.2)Based on the linear representation of an hexarotor UAV's dynamic model,a flight controller based on the sliding mode control method is designed.The controller can control the height and attitude of hexarotor UAV,and is robust to the uncertainty of the hexarotor UAV and the unmodeled dynamics of the rotor.In the design process of the flight controller,the sliding mode surface is designed by the method of pole placement,and control law is designed according to the linearly expressed hexarotor UAV model and the reaching law.In order to verify the effectiveness of the flight controller,the simulation experiment was carried out in the Simulink environment.3)Based on the flight controller,a fault-tolerant control algorithm based on control allocation is designed.The algorithm establish an optimization problem in the case of failure of the rotor system to achieve a reasonable distribution of control signals generated by the flight controller.In addition,in this paper,a method is proposed to solve the optimization problem,which can reduce the consumption of computing resources.Compared with the result of another fault-tolerant control algorithm of a multirotor UAV rotor system,the superiority of the fault-tolerant control algorithm proposed in this paper is proved.