Research On Key Modeling And Controlling Techniques For High Acceleration Precision Motion Stage

Chip packaging plays an important role in Integrated Circuit industry. Andhigh acceleration precision motion stage is the core moving plant in chippackaging equipment. With development of techniques, in IC packaging, the chipsize gets smaller and smaller, the distance between the leads gets smaller andsmaller, however the production efficiency is required much higher, all of theserequire the motion stage have got higher velocity, higher acceleration and higherpositioning accuracy. These indicators make the motion stage design and relevanttheoretical research on control system faced a great challenge.Based on the self-developed high acceleration precision motion stage,aimed to movement typical operating conditions, this dissertation analyzed thecharacteristics of permanent magnetic synchronous linear motors, and researchedon the key techniques of model identification and control system design torealize stage positioning fast and high precisely.First part, considering the high acceleration precision motion stage isdriven by linear motors directly, analyzed the thrust fluctuation of linear motor,modeled the friction model of the motion stage, and identified the modelparameters. And then the model structure of the motion stage is estimated. Andthe model parameters were identified with the frequency response method，andverify the effectiveness of the model.Second part, researched on the key control techniques based on the model ofthe motion stage. Trajectory planning is carried out by an asymmetric S planningcurve which can suppress the vibration. Zero phase error tracking feedforwardcontroller is designed according to the closed loop identification of the systemwhich can improve the tracking accuracy and to compensate the time delayimpact of systems. Disturbance observer is used in speed loop to achieve theparameter uncertainty and interference suppression with PID control. Positionloop uses PID control to achieve the trajectory tracking. The friction disturbanceis compensated based on the model for low speed part. And Matlab/Simulink isused to test the feasibility of the control algorithm.Finally, the experimental system is built for high acceleration precision motion stage performance test and experimental studies based on real timeinterface dSPACE system. And the test results show that the motion stage canachieve maximum acceleration15g in X axis, and16g in Y axis. The designedcontrol system make the stag response time reach in less than9ms positioningaccuracy within±1um to X axis, and6ms positioning accuracy within±1umto Y axis. These indexes have reached the requirements of present foreign highacceleration precision motion stage for packaging equipment.