Research And Development Of Linear Drive Aerostatic Precise Positioning Control System Based On PMAC

Precision positioning is one of the key components of precision machinery. It provides a loading platform that can achieve precision positioning and precision machining for microlithography technology, CNC machining, biological technology, nanometer surface shape measurement and other fields. The positioning table with air bearings that based on air support and linear motor direct-drive technology has been a hotspot in the research of the high precision technology at home and abroad recently.Linear drive aerostatic positioning platform is a mechatronic system, and it set technologies of gas static pressure guide rail, linear drive, numerical control, static and dynamic analysis, optimization, automatic control, test and experimental analysis into a comprehensive part. Among them,control system is the key to realization of high precision positioning in positioning stage.This paper completed to build a closed-loop control system of large stroke linear drive aerostatic positioning stage, and improve the positioning precision of positioning platform. Mainly from the aspects of gas floating positioning platform closed loop control system overall scheme design, PC control software development, control algorithm, the positioning accuracy measurement, compensation, the paper completed the research for linear drive air-float platform. The main contents are as follows:1、Researching for the key technology of linear driving aerostatic positioning stage at home and abroad. Through the analysis of the characteristics of the control technology, selecting the suitable method for this subject and building aerostatic positioning stage hardware closed-loop control system.2、According to requirements of research this topic aerostatic positioning stage, developing a open precision positioning stage software control system that has communication, manual download, online instruction terminal, programming and execution, parameter setting and movement state monitoring functions based on VC++, and using the modular design thought.3、Analyzing the effect of the motion parameters in the PID control algorithm on the platform position, velocity and acceleration motion response characteristics. Building a speed-feedforward and acceleration-feedforward PID control algorithm model and applied to the controller. Analyze the step response of the system characteristic and the sine wave response to adjusting the control parameters.4^Design the positioning accuracy measurement experiment scheme, and test the positioning platform movement characteristics under Traditional PID control in PID-speed feedforward acceleration feedforward control algorithms and the positioning accuracy. And based on the analysis of the positioning error, establish the error compensation methods that based on clearance compensation and linear compensation, and analyze positioning accuracy after the error compensation.