Research And Design Of Four Axis Attitude Control System Based On PIDNN

Four-axis UAV,as one kind of Multi-rotor type unmanned aerial vehicle,owing to its simple structure,independent hover and vertical lift,will be the development trend in UAV field in the future with broad values in scientific research and application especially suitable for military investigation,precision agriculture.However,there is a great difficulty in control system design because the four channels are required to control the six degrees of freedom through four channels during the flight control process,and there is a clear coupling between the control channels,therefore the four-axis aircraft is a typical strong coupling,nonlinear.In this paper,the four-axis aircraft is used as the research object.Firstly,the structural frame and the motion shape of the four-axis aircraft are analyzed and the dynamic model is established.Then,the hardware and software system of the aircraft are designed and implemented using the modular design method.This platform is carried out on the operation of the transplantation and attitude control algorithm research,and ultimately to achieve the aircraft's own hover.The main research contents are as follows:(1)In this paper,the research and development of the four-axis aircraft in recent years are expounded in details.Based on the flight mechanism and physical structure of the four-axis aircraft,the dynamic model of the four-axis aircraft is established by applying the kinetic theory and mathematical method,which brings a theoretical basis for the research of control system.(2)According to the functional requirements of the four-axis aircraft,the modular design method is used to design and implement the hardware and software system of the aircraft,and the experimental platform is built.In the aspect of hardware,the design of sensor module,power module,motor drive module and wireless remote control module are mainly completed.Aiming at the technical requirements of the four-axis aircraft control system,the selection of micro-controller,DC-DC power conversion chip and attitude sensor is studied in detail,and the working principle of MPU6050 inertial measurement unit and NRF24L01 wireless transceiver module is analyzed.The inertial measurement unit has a problem in the attitude measurement and gives the corresponding solution.In the aspect of software,the transplantation of ?C / OS-?? on STM32 platform,wireless communication design,sensor data acquisition and attitude solution,attitude control design and serial data transmission design are all completed.This paper describes in detail the process of transplanting the ?C / OS-?? operating system on STM32,the design method of wireless communication,sensor acquisition and aircraft attitude control,and the principle of DMA serial communication,and gives its detailed flow chart.(3)Research on attitude control algorithm for four-axis aircraft.The kinetic model is used to linearly process the dynamic model,and the PID neural network is used to realize the attitude control.The gradient learning algorithm causes the weight to fall into the local optimal solution during the learning process.The weight optimization method of the group algorithm,and the simulation on the MATLAB platform.(4)Verify the effectiveness of the design scheme and algorithm by hovering the flight test.Aiming at the algorithm designed in this paper,the autonomous hover of the aircraft is realized,and the feasibility and effectiveness of the attitude control algorithm are verified according to the change of attitude angle.