| The closed aerostatic positioning stage driven by linear motor is a kind of typical precision machinery structure. Aerostatic guideway because of its high precision, long service life, small frictional resistance, and pollution-free advantages, it is applied to precision, ultra-precision measurements and micro-nano processing areas widely. Meanwhile, linear drive has a simple structure, little thrust-weight ratio,high stiffness, and there is no inter-segments, greatly improves the machining efficiency and machining accuracy.Precision positioning stage is one of the key components in 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. Linear driving of the aerostatic bearing positioning stage is a mechatronics system, it needs to be applied to the aerostatic guideway technology, linear drive technology, numerical control technology and principle of automatic control and other technology. The capacity and stiffness of aerostatic bearings can determine whether the stage can normal and stable work or not. The control system, compensation of positioning accuracy and the research of2d contour precision played a very important role in the stage positioning accuracy and two axis motion precision. The objective of this essay is to improve the positioning precision of the aerostatic positioning stage, and study the two-dimensional motion contour error and related kinetic characteristics. And it also establish a good foundation for two-dimensional closed aerostatic positioning stage manufacturing. Therefore, this paper research the two-dimensional closed aerostatic positioning stage by using numerical simulation, control analysis and combining with experimental research methods. The main research contents are as follows:1、Aerostatic guideway internal fluid of different eccentricities and air supply pressure were studied, and pressure, velocity field distribution diagrams were got. The influence of eccentricity and air supply pressure on the load capacity, stiffness were further analyzed. In addition, laser interferometer and small pyramid reflectors and so on are applied as experimental devices to test the capacity and stiffness of aerostatic guideway.2、Established a two-dimensional motion control system model of two-dimensional closed aerostatic positioning stage. And the two-dimensional motion contour precision of two axis separate control and coupling control are simulated based on MATLAB software.3> The two-dimensional aerostatic positioning stage was simulated by combining with the method of dynamic simulation and control analysis. A mechatronics integrated simulation model was established by combining with the mechanical structure and movement control system of aerostatic positioning stage, then studied its position, velocity, acceleration motion characteristics under the influence of control parameters Kpp, Kvp, Kvi.4、Design the single axis linear positioning accuracy measurement experiment scheme, and test the positioning accuracy of the Y axis of two-dimensional gantry aerostatic positioning stage. The Y axis workbench positioning accuracy are compensated by gap compensation and linear compensation method. Also test the two axes joint motion precision of the X axis and Y axis by using the Ballbar. |
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