The Design Of A Small And Low-Altitude Unmanned Quadrotor Aircraft

Unmanned quadrotor aircraft is a. compact and unique way of flying VTOL. Due to the advantage of its small requiring area for taking off and landing, as well as the great ability of keeping navigation attitude, it has board applications in military and civilian areas.This project belongs to WenZhou Science and Technology Bureau, which is intended to design and make an experimental prototype of quadrotor aircraft. The subject has preliminarily made research and design on the overall structure and flight control system using the existing technology such as PID control and brushless DC motor drive technology. Equipped with a communication module, the prototype could not only realize the defined flight movement, but also could execute simple real-time monitoring function.Firstly, through analyzing the structural characteristics and working principle of the aircraft, combining the relevant flight parameters, this paper establishes mathematical modeling, constructs six channel transfer function for the attitude and position movement, which introduce four independent control channels. Using the classic PID control method, we simulate the hovering attitude and position control law to verify the feasibility of the control strategy.Then the overall design is made, including the fuselage overall design, energy/power plant design and landing gear design. To determine the lift device selection, a rotor tension test platform is made. This article focuses on hardware circuit part of the aircraft, including flight controller, motor speed control module,RS232communication module and video monitoring module. Flight controller is based on ATmega644microprocessor, which joints three-axis gyroscope, three-axis accelerometer and pressure altimeter to obtain and calculate the AHRS information in real-time. Ground receiving equipment displays videos that transferred from the monitoring module attached to the aircraft through wireless image transferred system. The software is divided into the algorithm and PC interface section. Algorithm is written in C language to realize the function of PID control, PWM motor speed control and sensor data correction. PC software sets the parameters of the aircraft through the serial ports, simulates current3D state and plans simple waypoints.