Research On Flight Control System For Quad UAV Based On STM32F4

Quad-rotor unmanned aerial vehicles(Quad UAV) is a flight device with six freedom degrees,which is able to take-off and landing vertically. It can fly at low altitude with low speed, hover in the sky, and it can record flight images if equipped with a micro camera. The different between classical helicopter and Quad UAV is that, its structure is simple, flying power is strong, and it has much more load. Without tail rotor mounted which can balance gyrostatic moment, the Quad UAV can be controlled easily, etc.In recent years, as its research and development,Quad UAV was gradually used in unmanned regions because of its advantages, such as humanness' reconnaissance,plant protection,electric power supervision,and other fields, especially in some high risk trash and task that human is difficult to finish.Quad UAV has a bright future for application.This article was based on the domestic and foreign research situation,the key technologies and application prospects of Quad UAV. Then choose a micro quad-rotor as the study. According to flight philosophy of a quad flight, established the nonlinear mathematical model for Quad UAV. Investigated the attitude algorithm of a strap down navigation system(SINS) and the control algorithm of a flight control system(FCS),at last built a physical platform so as to complete hover in the sky and remote control.Firstly, dissects the style of movement and the principle of flight for a micro quad flight,deduced the mathematical model. In order to do this, build the space coordinate system first,then use Newton-Euler's force law, equation of a flight, and the dynamic static model of the rotor to derive the nonlinear mathematical equations of a quad-rotor. Furthermore, choose the appropriate input and output, include the state volume of course, trim and linear the flight at hover in use of MATLAB commands and tools, and finally get the linear function between output and input, simplified the model.Secondly, designs the feedback channel for the plant on the basis of the characteristics of close loop control(CLC). In touch with common inertial measurement unit, derived the formula to solve the aircraft attitude. Then designs an Extend Kalman Filter to estimate the optimal body posture under the features of the sensors, by which can get the attitude and heading information of the plant. And finally provided an reliable parameters of the feedback for a stable flight control system.Thirdly, after linearizing transfer function model, analyzes its stability. Regulates each control channel by classical control theory. A cascade PID controller was designed to do this.Then build MATLAB/SIMULINK environment to simulate the designed controller of the system. Finally, improve the performance of the cascade PID controller through debug repeatedly.Finally, establish a research platform to finish he hardware and software design according to the requirement of the system. Select STM32F4, a series of STMicroelectronics' s products, as the main controller of quad flight control system and complete the transplantation of software design and control algorithm of the controller. Then take some experiments for actual flight test and analyzes the result.