Research On Control Of A Four Rotor Unmanned Aerial Vehicle System With External Interference And Actuator Failure

In recent years,with the continuous progress of processors,sensors and UAV technology,quadrotor UAV,as a kind of rotor aircraft with simple structure,easy operation,strong mobility and low cost,has been widely used in military,agricultural,civil,commercial and other fields,and has attracted many researchers’ attention.However,with the diversification of the application environment of quadrotor UAV and the increase of flight missions,it is vulnerable to external interference,such as wind disturbance,actuator failure,etc.,which makes it difficult for quadrotor UAV to complete its mission and there is a risk of crash.Therefore,this paper conducts relevant research on the anti-interference ability and preset time control of quadrotor UAV,aiming at maintaining stable,effective and accurate control under external interference and actuator failure.The main research of this article is as follows:(1)A finite time disturbance observer is designed to effectively estimate external disturbances during the flight of a quadcopter unmanned aerial vehicle.Design a new type of terminal sliding mode controller based on interference observer on the basis of terminal sliding mode,which makes the control system of a four rotor unmanned aerial vehicle more stable and reliable.The simulation experiment results show that the interference observer can effectively estimate external interference and ensure the stable convergence of the quadcopter unmanned aerial vehicle system in a finite time;(2)In the previous work,a nonsingular terminal sliding mode controller is designed,which is a finite time control method.However,this controller cannot estimate the convergence time and has singularity weaknesses.To address these issues,a new design scheme for non singular sliding mode surfaces was proposed and combined with fixed time control.Design a fixed time control method by using a fixed time disturbance observer to counteract the disturbance,and provide an upper bound for the convergence time estimation of the system.Through the simulation experimental results,it can be seen that the fixed time controller can not only accurately track the trajectory within a fixed time,but also estimate the accurate convergence upper bound time,while reducing the chattering.(3)Aiming at the problems of actuator failure and external interference of quadrotor UAV,a preset time interference observer is designed to effectively estimate the composite interference.Then the disturbance observer is combined with the preset time sliding mode controller to design a preset time sliding mode controller suitable for external disturbances and actuator failures.This controller can further improve the anti-interference ability,stability and accuracy of the quadrotor UAV.The simulation results show that the quadrotor UAV can accurately track the desired trajectory within the preset time and has good stability in the case of external interference and actuator failure.