Trajectory Tracking Controller Design For Quadrotor Aerial Vehicle

With the development of science and technology,the application of the technology of embedded processor and micro sensor makes quadrotor more and more tend to be intelligent and multi-functional.The special mechanical symmetric structure of quadrotor's rotors and their speed is controlled by independent motor respectively,so as to make it easier to control the aircraft and more flexible to fly,so the quadrotor occupies an extremely important position in military field and civilian field,and attracts wide attention of scholars.In the design of the flight control of quadrotor is a difficult task because it is a multivariable,under-actuated and nonlinear system.The main task of this thesis is to design the corresponding control algorithm to make the quadrotor can fly according to the scheduled trajectory with external disturbances.This thesis adopts the double closed-loop control structure;the control task is decomposed into three modules:height control,position control,attitude control.Position controller and height controller of outer control loop,attitude controller for the inner control loop.Firstly,for the realization of the quadrotor tracking a scheduled trajectory with the constant disturbance,the thesis combines integral Backstepping method with nonlinear adaptive control technology to give the corresponding trajectory tracking controller.By Lyapunov stability theorem,the control algorithm can online real-time accurate estimate the value of the constant disturbance in order to realize accurate control,enhance the robustness of the system.Secondly,for the time-varying disturbance,the trajectory tracking controller is proposed based on the sliding mode control with the observer to achieve the control of tracking a scheduled trajectory.The observer is used to estimate the unknown external disturbances,and the feedforward compensation is used to suppress the influence of the unknown disturbance to the system.By Lyapunov stability theorem,this control algorithm can get the value of time-varying disturbance in time and improve the stability of the system.Finally,in the end of this thesis,the mathematical model of the quadrotor with disturbance is simulated by using the simulation tool of Matlab.Through simulation results can be known,is proposed in this thesis based on observer based sliding mode control algorithm and the adaptive backstepping control is correct,so as to quadrotor application in actual engineering provides an important theoretical basis.