Autonomous Control System For The Quadrotor Unmanned Aerial Vehicle Based On Digital Signal Processor

Quadrotor UAV(unmanned aerial vehicle) is a kind of VTOL(vertical takeof andlanding) UAV, who has simple structure and many good performances. It also has perfectmaneuverability, mobility and flexibility for both military and civilian usages. Quadrotoris an under-actuated system with four input forces and six outputs, while it is an unstablenonlinear system with multiple variables and strong coupling. Compared to fixed-wingUAV, controlling the quadrotor is so difcult that the technology is not matured enough.But in recent years, owing to its advantages, the quadrotor has attracted great attention ofresearchers, and it is one of the international hot spot in many research fields.This thesis designs an experiment platform for the autonomous flight control systemvia digital signal processor, which takes quadrotor as the research subject. I have com-pleted the flight control system hardware and software design, such as micro-controllersystem design, brushless DC motor driving, acquisition and processing technology of thesensor data, autonomous control, and so on. And then, autonomous control of the rollangle, pitch angle, yaw angle and height altogether four degrees of freedom in hoveringstate have been obtained. The research contents are as follows.Firstly, according to the overall structure of the quadrotor UAV autonomous flightcontrol system, the hardware and software system are designed, including componentselection, hardware circuit, interface communication design, and so on. After carryingout a lot of debugging, problems in the hardware and program design are solved.Secondly, the lift force coefcient and torque coefcient are measured through theexperiment, providing the model parameters for the control algorithm. And open-loopcontroller is designed for the quadrotor’s actuators. Based on the dynamic model of thequadrotor, the six degrees of freedom system is decomposed into two linear subsystemsafter feedback linearization. They are inner-loop attitude subsystem and outer-loop posi-tion subsystem, which are connected by a nonlinear coupling variable. PD controllers aredesigned for the two subsystems, and the C language program for the implementation ofthe control algorithm is completed.Finally, based on the platform and the control algorithm, the flight control exper-iments of the attitude and height are carried out. The results show that the hardwareplatform structure in this thesis is reasonable and the control algorithm is efective.