Research On Structure And Bearing Characteristics Of Piezoelectric Active Control Air Bearing

Air bearing has been widely used in motion systems in precision manufacturing,measurement and other fields due to its advantages of low friction,low heat generation and high precision.With the increase of processing load and the improvement of manufacturing accuracy to nanometer or even sub-nanometer level,the performance of air-bearing for motion system is severely challenged.The improvement of the bearing capacity and stiffness of air bearing has become a hot issue in international academic field.Based on the idea of actively adjusting the shape of the air film of the air bearing to adjust the bearing capacity and dynamic stiffness of the bearing,the research on the new configuration,prototype development and performance test of the piezoelectric active control air bearing are carried out in this thesis.The main research results and innovations are as follows:1.The structural characteristics of circular active air bearing with annular piezoelectric array are analyzed.The defects of this configuration,such as small dimension and amplitude of deformation control of the air bearing,are discussed.A new configuration of rectangular active air bearing with double-row piezoelectric array is proposed.2.The piezoelectric-structure relation model of the air-bearing is established,and a twodimensional simplified model calculation method ignoring the effect of flow field is proposed to realize the deformation calculation of the floor structure.According to this,the key structural dimensions and piezoelectric array arrangement of the air bearing are optimized,and the structural design of the rectangular piezoelectric active air bearing is completed.3.A three-dimensional finite element model of the active air-bearing with rectangular structure is established,the structural modal analysis of the active air-bearing is carried out,and the variation law of structural deformation and bearing characteristics of the active air-bearing with piezoelectric driving voltage is simulated and analyzed.The results show that with the increase of the driving voltage,the bearing capacity of the air bearing is also enhanced.The maximum bearing capacity at 10 um nominal film thickness can reach 173.8N,which is 17.5% higher than that of the conventional air bearing of the same size.4.The experimental scheme design of deformation and bearing characteristics of rectangular structure active air bearing was carried out,and the corresponding experimental device was built.The test analysis of deformation and bearing characteristics of air bearing with piezoelectric driving voltage was completed.The test results show that the error between the deformation simulation of air bearing and the measured results is less than 5%,and the error between the load-bearing characteristics simulation and the measured results is less than 5%,which verifies the correctness of the simulation analysis.The related research has laid a foundation for the research on dynamic regulation and dynamic stiffness enhancement of piezoelectric active air bearing.The related research results have broad application prospects in ultra-precision equipment such as silicon wafer detection motion platform,precision air bearing turntable,laser drilling equipment and precision motion platform.