Research Of Property Of Low-speed AC Servo System Based On EKF

In recent years, with the rapid development of microelectronics and control technology, AC Servo system has a wide application in the region of factory automation, numerical control machining and robot. In AC servo system, motor’s property, especially during it low-speed running impacts system’s property to a large extent, that is why the study on property of low-speed motor is particularly important. This article find out problems after experiment and debugging the AC servo system based on the laboratory experiment platform, and improve the system’s property in low-speed through study on theory and simulation.First of all, this article lists the background and significance of this topic, and then summarizes the development of AC servo system, especially focusing on low-speed AC servo system. On this basis, this article proposes that using extended kalman filter to solve the problem of low precision when system is in low-speed.Secondly, the structure of AC servo system is introduced, focusing on main parts of the system in terms of work principle, parameters and so on. And it introduces one of important execution element of AC servo system:permanent magnet synchronous motor, including its structure, working principle and mathematical model. What’s more, I analyze PMSM’s electromagnetic torque, and ultimately transform the control of torque into the control of electric current, and give a detailed description of coordinate transformation theory which is one of important vector control technology for motor.Thirdly, on the basis of PEWIN32PRO, which is the executive software of PMAC, I performs experiments to observe the system’s responsiveness, and do adjustment about PID parameters and the dynamic property of the system. After that, I do lots of experiments, and find that the system has good responsiveness when in high speed, but poorer responsiveness when in low speed, such as Larger speed fluctuation, obvious crawling phenomenon of flywheel attached to motor shaft.Finally, this subject applies extended kalman filtering (EKF) technology into the control of system in low-speed, completing the estimation of motor’s speed. And do a simulation when joining EKF in AC servo system using Simulink in Matlab, and the results show that, using EKF technology to detect low-speed can improve speed tracking property of system, which has practical value.