Research On The Key Technology Of Ultraprecision Stage With Large Travel

Precision micro-displacement stage system with high precision and high resolution plays an important role in modern industry and scientific research field. There are some defects existing in the whole performance and the demand of environment is strict in the developed ultraprecision stage. The key technology of precision stage is the urgent need for laying a foundation of developing new large travel ultraprecision stage with balanced performance and fitting the industry environment. By comparing the ultraprecision stage developed at home and abroad, it is concluded that the advanced structure material, aerostatic guideway and direct drive technology are the key technologies of ultraprecision stage. These related technologies were researched in this paper.The thermal analysis, thermal-structure coupling analysis and transient thermal analysis are applied in nine common materials by using the finite element software ANSYS. The results indicate that the zero expansion glass ceramic has the best performance in the materials analyzed; the silica ceramic is slight interior. Due to the expensive cost of zero expansion glass ceramic, the silica ceramic is a promising material for ultraprecision stage while the extreme performance is not pursued.A new analysis procedure based on commercial finite element pre-and post processor is put forward when the air lubrication theory with porous restrictors is analyzed. This method acquires the ability for analyzing the complicated porous restriction engineering problems by improving the solver's calculation efficiency and the utilizing rate of memory. The factors which influence the performance of porous restrictor are analyzed for its design. The experiment scheme and devices are designed in the experiment research of air lubrication with porous restrictors. The permeability testing and loading experiment is carried out and the machining process of porous materials for blocking is researched. The experimental results indicate that the experiment result curves run parallel with the FEA result curves approximately; the bearing inclines expressly which cause the great deviation between the experiment results and FEA result due to the ununiformity of micropore blocking over the bearing surface. The more serious the blocking is, the larger the ununiformity of permeability The guideways types which are suitable for ultraprecision stage are analyzed when the structure design of aerostatic guideways is researched. The influence trend of motion guideway's length and guideway's travel is obtained by analyzing the motion error of the motion guideway. The component, property and transfer coefficient of errors are analyzed. And the accuracy allocation method is discussed, too. The design principle is obtained after the typical bolt fastening structure is analyzed with finite element method and orthogonal test.The math model of the direct-driven control system is established, and the exterior disturbance and compensation proposal is analyzed. The unit-feedback PID control, PID+acceleration feedforward control, position and velocity dual loop feedback control system are built with SIMULINK and the control effects are compared when the motion part consists of different materials. All of the control model and the Smith predictor are analyzed to seek the ideal control model. The slider made of silica ceramic can lighten the weight of motion parts efficiently for its smaller density. So the slider made of silica ceramic has better control performance than made of other materials obviously.