Flight Control System Of Four Axis Aircraft Research And Design Based On STM32

Four axis aircraft is a new micro vehicle,it's structure is simpler than other aircraft,although it's volume is small,the stability of the flight is excellent,and able to vertical take-off and landing,also it takes up less space and it's requirement for take-off and landing conditions are not high.Otherwise,it has low failure rate and easy to maintenance.Because of these characteristics,four axis aircraft has broad application prospect in the areas of military and it develops very quickly.Firstly,the development history and research status of four axis aircraft are introduced,then lists some typical aircrafts at home and abroad,this paper introduces the basic structure and working principle of four aixs aircraft,analyzed the flight states of the four axis flying vehicle simply.Besides,the importance of attitude algorithm for four axis aircraft is introduced,gives two attitude representation methods,by comparing to select the four-digit representation of the smaller computational complexity and the deadlock problem of the gimbal.Kalman filter algorithm and complementary filter algorithm are analyzed.And a complementary filtering algorithm,which is more suitable for small four axis aircraft,is chosen as the method of attitude calculation.After the calculation is successful,the four variables are converted into Euler angles to represent the flight attitude of the four axis aircraft,the deadlock problem of Euler angle joint is avoided successfully.Moreover,PID controller is introduced,the choice for nonlinear system has good control effect of cascade PID controller,in the form of PWM drive four hollow cup motor to realize four axis aircraft propeller rotation.Secondly on the basis of theoretical analysis,complete the hardware design of the four axle aircraft,selection of STM32 as four axis aircraft's control chip,choose 3 axis acceleration sensor MPU6050 as the inertial measurement unit,through HC05 module and remote control equipment.After that,written and designed the program code for the control system and remote control of the four axis aircraft.Finally,made a prototype of a four axle aircraft and conducting flight experiments,through the actual flight conditions on the parameters of the aircraft modification and debugging of many times,the stable flight of the four axis aircraft is realized in the end.