The Research Of Portable Brake Performance Tester Calibration Device Based On AC Servo System

In recent years,the control system of AC servo motor has always been a research hotspot, because of its advantages such as high accuracy, fast response and so on. In metrology, we often use the control system of AC servo motor, when needing mechanical auto-control. The nature of metrology determines that the system must have high accuracy and quality. The design and research of this article are just under this requirement.This article mainly makes intensive study of the control system of AC servo motor. Firstly, we analysis the mathematic model of Permanent-magnet AC servo motor control system which is under the three-phase stator winding(the three-phase static coordinate system of ABC). Since the model which includes many variables is so complex that it is difficult to be controlled, on the premise of magnetic potential and power conservation, we transform the mathematic model to the model under two-phase rotating coordinate system of d and q. In this coordinate system, adopting vector control strategy which is “id=0”, we can realise the control towards AC servo motor. The strategy is simple, easy to implement. Based on the theory of clark transformation and park transformation, under the condition of id=0, we can control AC servo motor by controlling the iq. In order to ensure the precise position of control system, using current loop, speed loop and position loop constitute three closed loop control system. The current loop feeds back the currents of electronic winding in AC servo motor through a hall sensor, and the speed loop and position loop feed back the position of the AC servo motor rotor and its speed through a 17 bit incremental photoelectric encoder. In the vector control strategy based on “id=0”, using the SVPWM control technology, we can produce PWM waves to control the six power switch in three-phase inverter circuit, realizing control towards AC servo motor.Then, after the research of permanent magnet synchronous ac servo motor control system, we introduce its application in portable brake performance tester static calibration device which is often used in metrology. With motor control circuit,buttons and LCD display, we can get a whole portable brake performance tester static calibration device. In the end, we verify the reliability of portable brake performance tester static calibration device by analyzing the experimental data, and at the same time, we also proved in this paper, the permanent magnet AC servo motor control system design has certain feasibility.