Quadrotor Attitude Control Study Based On Multiple Model Adaptive Control

Quadrotor,as a special one of the UAV family,has its own features: low cost,small size,simple mechansim and high mobility,which is applied to surveillance and seconnaissance,emergency rescue,aerial photography, atmospheric monitoring and other applications.Because of its vast application prospect in military and civil field,quadrotor sets off a hot wave of research all over the world. And control system research is the core of quadrotor study.Quadrotor is a multivariable,under-actuated,strong coupling and nonlinear system.Undoubtedly,it enhances difficulty to the control system research of quadrotor.This paper mainly studies the control system design of quadrotor in the case of low speed or hovering condition in the room.And multiple model adaptive control(MMAC)is first applied in the control system design of quadrotor.The purpose of the control is to make the quadrotor posture achieve stability in a short time, and the change of location is not big.After analyzing the basic principle of quadrotor, dynamics model is built.In addition, the basic theory of multiple model adaptive control is introduced in this paper.In this paper, the PID, LQR-multiple model adaptive control and H-infinity-multiple model adaptive control are used to control the quadrotor:Firstly, the nonlinear model of the quadrotor is analyzed, and the channel model of roll angle, pitch angle, yaw angle and altitude are established, and the control and simulation are realized by using PID.Secondly,building multiple model adaptive control system based on LQR.First, the model is linearized in the 9 feature working points and 9 linear subsystems are established. Then,by using the principle of the linear quadratic regulator(LQR), a sub-controller is designed for each subsystem.The switching rule of each subsystem is also designed,which is used in the control process.In addition, using Simulink to build a simulation model of the control system.By comparing with PID control,it has been verified that the response speed is faster and the overshoot is smaller.Finally, considering the fact that the quadrotor is affected by the environmental wind,the robust H-infinity control theory is used to design subsystem controller.Then using the method of linear matrix inequality(LMI) solve H-infinity state feedback gain matrix.By the MATLAB/Simulink simulation, it is found that multiple model adaptive control system based on the H-infinity control has good response performance and robustness to external disturbance.