Analysis Of Static And Dynamic Characteristics Of Ultra-Precision Hydrostatic Guideway And Indentification Of Model Parameters

In recent years, optical parts are used more and more widely in civilian use, national defense and space technology. Ultra-precision machine tools are the most important equipment for optical machining. The equality of optical parts is guaranteed by the characteristics of ultra-precision machine tools. However, there are many factors which affect on these characteristics, guideway is an important factor. In order to make the guideway have higher stiffness and guiding precision, the closed hydrostatic guideway is designed. In facts, the work table must carry load, so the slider will have an offset which will affect on the static characteristics of hydrostatic guideway. Otherwise, guideway rails deform under oil pocket pressure, which will affect on guideway stiffness and guiding precision, but a little research on rail deformation has been done.The hydrostatic guideway is designed for ultra-precision machine tools according to the design standard, and the static characteristics of guideway are analyzed considering slider offset and rails deformation. Meanwhile, the dynamic characteristic of guideway is analyzed using simulation and experiment analysis.The design targets are obtained with analyzing the machinability of ultra-precision machine tools, and then determine the structure of guideway. The design parameters are obtained with the method of existing hydrostatic bearing.. The relationship formations of slider offset and stiffness, carrying capacity and guiding precision are obtained respectively. And the relationship curves are protracted. The effect of slider offset on hydrostatic guideway is analyzed and the slider offset ratio is selected.The static characteristics of hydrostatic guideway are analyzed using ANSYS in the third chapter. An elastomer of virtual material properties is used to simulate oil film, so that the relationship of oil film clearance and pressure can be represented in a certain range. The rails deformation is obtained after the establishment of the FE model of guideway. As follow, the effect of rails deformation on stiffness and guiding precision can be analyzed.The simulation and experimental methods are used to analyse the dynamic characteristics. And the nature frequency and mode shape are obtained. After analyzing the difference of simulation and test, the correctness of FE model can be verified and damping model parameters can be calculated which can provide the basis for analysis of dynamic of guideway.