Modeling And Analysis Of Active Magnetic Bearing System Based On The Optical Reflector

Active magnetic bearing has been paid more and more attention because of its many merits such as no mechanical contact, no need of lubrication, no wear, no noise, high precision and long service life, etc. The optical reflector mentioned in this paper is a system with large active scope and high precision, however, the bearing of its spindle has a great influence upon its precision. Therefore, the choice of bearing is critical to improve precision of the optical reflector. The bearing selected for the spindle must guarantee that optical reflector can work not only in large scope but also with high precision. Hence, active magnetic bearing is selected for the spindle. In this paper, the main task, modeling and analysis of active magnetic bearing system based on the optical reflector, has been done, which will establish a theoretical base for the application of active magnetic bearing system to optical reflector system.First, single freedom degree mathematic model and four freedom degrees mathematic model have been set up respectively in this paper. On the basis of which, PID control model of active magnetic bearing with single freedom degree has been built. Simulations of step response of PID control under the interference of impulse sign from base and variety of rotor parameters have been done, respectively. And simulation of rotor uprising response under the interference of sine sign from base has been completed. In addition, simulation of neural network control has been carried out, and the results of simulation show that, for a complicated nonlinear system, neural network control has an advantage over additional PID control. Finally, the influence of displacement error of the rotor on light-beam stability of the optical reflector has been studied. The analytical results indicate that displacement error of the rotor has a minute influence on light-beam stability of the optical reflector. Consequently, it is guaranteed that the optical reflector system can obtain high precision, by using active magnetic bearings.