Motor Drive System Design And Flight Attitude Simulation For Micro Unmanned Aerial Vehicle

Due to its small size, light weight, concealment and mobility, easily realize hovering and advantage of low altitude flight, micro unmanned aerial vehicle (UAV) has been extensively developed in the military and civilian fields. UAV is proved to be not only a good aerial work platform, but also a multi-discipline theory research platform. Servo loop is an important part of micro UAV which directly related to its flight performance. Brushless DC (BLDC) servo loop gradually replaced traditional AC servo loop for its excellent electrical and mechanical performances. The simulation of flight control system is an essential mean to design and research mirco UAV to facilitate on system performance evaluation, testing and modification. This paper mainly focuses on the servo loop study and flight control simulation.According to the performance requirements of micro UAV, this paper selects a suitable BLDC motor, analyzes its performance, and formulates its design scheme. Firstly, the BLDC motor drive circuit is designed by PIC16F877 microcomputer as its main control chip. After constructing the peripheral circuit and debugging program, the motor starts and operates smoothly. Then based on such research, the paper proposed another design scheme which uses a specific integrated circuit ML4425 as motor driver. This method greatly downsizes the volume and simplifies the design procedure. Experiment proved that the design could well meet the performance requirements of BLDC motor drive.Servo loop is the actuator of the UAV flight control system. It realizes the flight attitude and track control according to the given instruction. This paper discusses some simulation analysis and research on the flight control system of UAV and establishes the mathematical model of micro UAV. The paper also deduces the state equations about the UAV's attitudes during its pitching, rolling, yawing and horizontal lateral moving by decoupling and linearizing its aerodynamics and kinematics equations. The design of controller optimizes the flight performance effectively. Simulation results show that the mathematical model is reasonable and the flight performance of the micro UAV achieves expected effects.