Research And Design Of The Control System For Quadrotor

The quadrotor,also known as the four-rotor helicopter,is a kind of multi-rotor aircraft.Its four motors directly connected to the rotors are symmetrically placed in the cross structure which is equidistant from the center of the body,and the adjacent motor turn to opposite direction,so,the flighting attitude and position can be controlled by adjusting the speed of the four motors,while the anti-torque in the course of the flight can offset each other.Its simple structural design enable it the advantages of vertical take-off and landing,simple control,being nonperishable,low cost and so on,these advantages make it widely used both in military aspects such as investigation,surveillance and communication relay,and in civil engineering such as atmospheric monitoring,traffic monitoring and video capture.With the study of the mathematical model of the quadrotor,it's obvious that quadrotor is a four-input and six-output underactuated system which has the characteristics of instability,nonlinearity and modeling uncertainty,and its attitude and position motion are coupled with each other.For such a nonlinear system,in order to control it stablely and reliably,attitude control and position control is the key to the entire controller.In this paper,the kinematics and dynamics models of the quadrotor are established according to the Newton-Euler equation,and then the linear PID control algorithm and LQR control algorithm are designed by the linearized mathematical model.In order to verify the correctness of the designed control algorithm,the simulation environment is set up in MATLAB/Simulink at first,then the simulation results of the quadrotor attitude and position control are obtained by adjusting the simulation parameters,and the reliable control of the quadrotor is realized theoretically.According to the design plan,taking a STM32F407VGT6 as the main chip,it designs the hardware circuit to achieve the control of attitude and position of the quadrotor with combining the attitude measurement system.In order to obtain accurate attitude and position information,the corresponding sensor output data is filtered firstly,then the filtered data is fused byusing the gradient descent method and the attitude calculation of the flight process is realized.In the end,the experimental platform is experimentally verified the experimental results show that the designed control algorithm can achieve stable and reliable control of the quadrotor.