The Linear Motor Input To The Unit Servo Stiffness And Adaptive Control

In order to meet requirements of the rapid-developing high speed cutting technology for high velocity feed, a newfashioned ero-transmission?feed system driven by linear motor had been developed. Compared with the conventional ball-screw feed system. linear motor feed system has outstanding characteristics, such as simple structure, high speed, high acceleration and high position accuracy. It is the revolution of machine tool feed system and will be used more and more widely.In order to maintain machining stability and reduce the effect of machining distrubance forces on the machining quality, exploite the high velocity and high response characteristics of linear motor drives in machining process, the servo control must achieve tracking performance as high as possible as well as rigid dynamic stiffiiess.The dissertation mainly disscusses the servo stiffness of linear motor drives. Firstly, the definition and evaluation method is brought forward since the servo stiffness of the linear motor drives takes on new features. secondly, the model of linear motor control system is given, a time-field simulation is performed using simulation software MATLAB&Simulink to evaluate the influence of control stmcture~ control parameters and mechanical characteristics on the feed drives dynamic servo stiffness. The simulation results are also verified by the dynamic stiffness experiment. To solve the problem caused by the change of moving mass during machining process, which will deteriorate the dynamic stiffness and servo performance of the linear motor driver, the adaptive control of the linear motor drive is discussed and simulation is also conducted.