Design And Implementation For The Control System Of Quadrotor Unmanned Aerial Vehicle

The quadrotor unmanned aerial vehicle(UAV) with six degrees of freedom can take-off and landing vertically, it can help investigation and fulfil the military task by using vision sensor onboard, and it can also complete corresponding task with other equipment .With the development of science and technology, the quadrotor micro air vehicle(MAV) appeared,compared with the traditional uav, it is smaller and better hidden, but is more susceptible to interference, and limited load ability put forward higher requirements for attitude algorithm method. In this thesis, attitude resolution and control strategy is studied based on quadrotor MAV.Quadrotor MAV is a kind of underactuated nonlinear system with strong coupling. In this thesis, the mathematical model is expressed by the euler angle, and the attitude transformation matrix is based on the four elements. Considering the structure characteristics and the actual working conditions, the simplified model is divided into a fully actuated system and an underactuated system. The fully actuated system includes the yaw and height system and the underactuated system includes the horizontal position and the pitch angle and roll angle system.The navigation attitude system of the quadrotor MAV consists of MEMS gyroscope,accelerometer and magnetometer. Considering the sensor characteristics,In order to save processor resources, the more simple complementary filter algorithm is chosen to replace the traditional calman filter for state estimation. A double loop PID controller for position and attitude is designed, and the controller performance is better with no disturbance indoor.The quadrotor MAV is more susceptible to disturbance, this thesis designed two kinds of sliding mode controller with stronger robustness, the second-order sliding mode controller(2-SMC) and the terminal sliding mode controller(TSMC). Both of the controllers should ensure yaw angle and height reach their desired values quickly, then the underactuated system can transformed into a cascade form. The sliding manifold is contructed via a combination of tracking errors of state variables. The stability of the system is demonatrated by Lyapunov theory. Contrast the simulation results, the sliding mode controller has stronger anti-interference ability, the 2-SMC can solve the chattering problem of sliding mode surface,the TSMC can further improve the control precision, response speed and restrain the system chattering.The quadrotor MAV with the STM32 as chip micro is designer in this thesis, its size is about 10×10cm and controlled by remote. Attitude estimation and a variety of control algorithm is programmed in this thesis. Flight experiments with or without lateral wind disturbance is carried indoor. With the use of open-source PC software and comparing the practical effects of the various algorithms , the result shows that the sliding mode control algorithm proposed in this thesis perform better. As the quadrotor MAV is more flexible in this thesis , the inverted flight is realized on the basis of the steady flight. Finally, in order to spread such aircraft, several future research areas are put forward.