Research On The Position Servo System Based On The Permanent Magnet Brushless DC Mortor

In the fields of Aeronautics and Astronautics, the traditional hydraulic and air steering-engines have many disadvantages such as high weight and low reliability. These disadvantages appear more and more obviously. With the materials science, power electronic technology and microelectronics technology developing, the permanent brushless servo system is used more and more widely due to its high power densities and controlled reliably.The thesis is aimed at the application of the space steering engine, develops the position servo system based on the permanent magnet brushless dc motor. The work principle and mathematical model of the brushless dc motor is first introduced, as the foundation for the following systematic mathematical. Then the thesis gives the commutation logic of the BLDCM, and chooses the PWM_ON control mode. And then the thesis introduces the basic work principle of the servo system, gives the three-loop system working principle and design principles. Through comparing several methods, the thesis chooses an improved PID control strategy. Finally the three-loop servo system is designed by engineering design method, from the current loop to the position loop. Then the thesis chooses appropriate regulators respectively and calculates the theory modulation parameters.The model was put up in the software MATLAB based on the theory analysis and calculation. The parameters which make the system working better were corrected by simulation. At the fundaments of the theory and the simulation, a prototype is designed and built. This system uses TI's TMS320F2812 as the control core. The power circuit was built in the form of three-phase inverter circuit. HCPL3120 is used as the drive chip. At the same time, the current and voltage protection circuit were designed. The system selects the 1.2kW brushless dc motor and the mechanical moving institution was designed to convert the rotation movement to linear motion. The software is designed by the blocking ideas. The software is designed to achieve the practical three-loop function. The experimental platform is connected by CAN communication to the central computer to achieve the purpose of the real-time control and feedback.Finally the experiments were taken on the experimental platform. Then the experiments'results of the speed loop and position loop were analysis, and the results prove the availability of the design. At the same time, the parameters are corrected to make the system working better. These works lay the foundation of the final utility of the system.