Study On Flight Control Methods Of Quadrotor

In recent years, quadrotor has become a research hotspot, with characteristics of the low cost, high performance, unique structure and special flight mode, which is widely used in military and civilian. As a result, more and more researchers and amateurs are addicted to research it. Quadrotor control is an important condition for the stable flight of quadrotor. The control algorithm is the main research content of this paper, also three control algorithms for attitude and position are designed, and then experiments are carried out in matlab, the dynamic and static performance of the three control algorithms are compared and analyzed at last of this paper.This paper's study based on matlab simulation software.The main contents and research of this paper include:1. Establishing nonlinear mathematic mode: this paper introduces the structure of quadrotor and the principle of its control, then a motor propeller model and a dynamic model of the quadrotor are established from the point of view of kinematics and dynamics.Sensor data filtering processing and attitude data fusion: quadrotor is an under actuated system. Therefore, the stability accuracy of the attitude data is an important prerequisite for quadrotor control, calman filter and first order low pass filter are designed to filter the sensor data,then simulating in the matlab simulation and test on a STM32 flight control board.2. Design of control system based on series connection PID control algorithm: the attitude and position are controlled by out loop PID, and euler angular velocity and linear velocity are controlled by inner loop PID. Meanwhile, simulate in the matlab simulation software. The results show that the quadrotor can reach the target position accurately and keep hovering.3. Design of control system based on LQR control algorithm: as a result of nonlinear multi input and multi output characteristics of quadrotor system, to linearize the quadrotor system in first order Taylor expansion.Design and control system based on modern control theory in LQR control algorithm. Also, simulate in the matlab simulation software. The results show that LQR control algorithm is also keeps hovering, however, there is some position steady state error and has overshoot.4. Design of control system based on Backstepping control algorithm: to remain characteristics of the nonlinear characteristics of quadrotor, design control system based on backstepping by Lyapunov stability criterion. Furthermore, simulate in the matlab simulation software. The results show that this sytem is superior to the series connection PID in regulating time and overshoot.5. Through the analysis and comparison quadrotor simulation results of series connection PID, LQR and Backstepping control algorithm that designs by Lyapunov stability criterion, comparative analysis of steady state dynamic performance of three kinds of control algorithms. The results show that the control algorithm based on backstepping method has the best effect.