Design Of An Aerial Photography Quadrotor Control System

The quadrotor is typical and strongly coupled underactuated system.As early as the beginning of the last century,some scholars began to study the quadrotor,but the results were not satisfactory due to the technical and economic restrictions at that time.Until 1990 s,with the rapid development of computer technology,microelectronic technology and automatic control technology,quadrotor once again aroused the interest of scientific research personnel,and many related scientific research projects and have obtained certain research results.Because the aircraft will be disturbed by the wind,air resistance and other external environment during the actual flight,it is difficult to establish its accurate mathematical model,which also brings some challenges to the design of the control system.Because of its simple structure and flexible flight,the quadrotor has been widely applied in military and civilian fields.In this paper,in view of the characteristics of the aerial photography quadrotor,the dynamic model is established by using the Newton-Euler equation,its kinematic model is established by using the four quaternion,and the analytic solution and numerical solution of the kinematic equation are obtained.Combined with the advantages and disadvantages of gyroscopes,accelerometers and magnetometers,a complementary filtering algorithm based on quaternion is designed in attitude algorithm.On the hardware side,PCB flight control circuit board with gyroscope,accelerometer,magnetometer and barometer is made,and it can connect GPS module outside.In the control system,on the basis of the traditional PID,the attitude balance cascade PID control algorithm,the high cascade PID control algorithm and the GPS fixed point PID control algorithm are designed to realize the attitude control and fixed point hover control of the quadrotor.Finally,a quadrotor test platform was built,and the outdoor flight test was carried out.The experimental results show that the quadrotor can achieve stable flight and high precision hovering,basically meet the design requirements of the aerial photography quadrotor.