Research On Dynamic Performance Of Linear Motor Servo System Based On PMAC

Linear motor constitutes one of the major functional components of high speed and highprecision machine tools, the dynamic performance of linear motor servo system has significantinfluences on the accuracy of feed drive mechanism in a machine tool.Targeting the linear motorservo system design of micro-cutting machine tools, influences that friction property, load propertyand servo control mode will have on the dynamic performance of the linear motor servo system inmicro-cutting machine tool was analyzed. Following research work has been conducted in this paper:(1) Linear motor servo systems of both a super-precision cutting machine tool and amicro-milling machine tool were established with motion controller being the core, combining withservo drive, linear motor, and the position feedback optical linear encoder. A hostcomputer softwarewere developed for the micro-milling machine.(2) Dynamic performance of two linear motor servo systems with different friction property wasanalyzed employing the step response and sinusoidal response which are provided with the servoparameters tuning tools of the motion controller. Results showed that linear motor servo systemwithout friction has faster response but is more prone to overshoot and has an inferior stability.Regress models of dynamic performance indicators were also developed through regress analysis toevaluate how friction property affects dynamic performance of linear motor servo system.(3) Dynamic performance of linear motor servo system with different load property or variousdrive mode were analyzed in terms of rise time, overshoot, settling time and following error. Resultsshowed that linear motor servo system with heavy load will have longer rise time and larger followingerror than its lighter load counterpart, but a shorter settling time was also oberserved.Linear motorservo system will have shorter rise time and settling time, thus faster response when driven in currentloop mode.That better profile accuracy will be achieved with current loop mode was confirmed afterconducted square and circle profile cutting with a micro-milling machine.