Research On Finite-time Control Method For Quadrotor Attitude System

Quadrotor is a kind of non coaxial multi rotor UAV which can realize vertical take-off and landing.It is driven by four independent motor systems with butterfly distribution as the power source of flight.Because of its advantages of simple structure,strong maneuverability and flexibility,quadrotor has a broad application prospect.However,from the point of view of control system,the quadrotor system is a typical multi-variable,nonlinear and strong coupling typical underdrive system,which has some challenges in the design of control system and system performance analysis.Therefore,the research on the control method of quadrotor UAV has not only theoretical value but also practical value.The control system of quadrotor can be divided into position loop control and attitude loop control.Compared with position loop control,the analysis and design of attitude loop control system is more complex,and the control performance is also higher.In order to improve the dynamic and steady-state performance of the attitude system of the quadrotor,many scholars at home and abroad have done a lot of research on the attitude control methods of the UAV,trying to use various nonlinear control methods.As a newly developed nonlinear control method in recent years,the finit e time control technology has attracted the attention and research of many scholars because of its fast convergence speed and strong anti-disturbance ability.Therefore,the main starting point of this dissertation is to use this new control method to design the quadrotor attitude control system to improve the dynamic and steady-state performance of the UAV attitude systemFirstly,this dissertation introduces the research status and finite time control theory of quadrotor UAV.a simple modeling analysis of the quadrotor system is carried out.The working principle,attitude control system and motor model of the quadrotor system are analyzed.Aiming at the attitude system of quadrotor,several common attitude description methods are introduced,which are direction cosine method,Euler angle method and quaternion method.According to different attitude models,the attitude control of quadrotor is studied based on the finite time control technology.Firstly,based on the Eulerian attitude model,according to the characteristics of slow rotation of yaw angle than roll angle and pitch angle in the attitude adjustment of quadrotor,the attitude trajectory planning based on the characteristics of attitude movement is carried out,and the attitude decoupling control strategy and attitude trajectory planning method are proposed,and the attitude finite time tracking control algorithm is designed by using the finite time control theory.Then,the problem of attitude control with limited angular velocity is considered in this paper.Based on the characteristics of the quaternion attitude model,using the homogeneous system theory and the finite time control theory,a finite time attitude control algorithm with constrained attitude angular velocity is designed,which can achieve the finite time attitude stability and meet the constraint conditions of attitude angular velocity.Finally,the attitude control experiment platform of the quadrotor is built,including the hardware and so ftware design,and an experimental verification of the attitude control method of the quadrotor was carried out.