The Research On Air Spindle Vibration Dynamic Model And Measurement

Ultra precision machining is one of the representatives of modern high-end manufacturing technology,which plays a very important role in electronic information technology,optical components,precision manufacturing equipment and national defense science and technology.The air spindle is one of the key components in the ultra precision machining machine,and the dynamic response of air spindle vibration directly affects the machining accuracy of ultra precision machine.Therefore,it is important to study the dynamics of air spindle vibration,the test of air spindle vibration vibration and the influence of dynamic response of air spindle in machining.In the thesis,the air spindle of ultra precision lathe is taken as the research object.The dynamic model of air spindle rotor vibration is established and the dynamic response is simulated.The displacement signal of air spindle rotor vibration is tested and the influence of dynamic response of air spindle on the surface quality of workpiece is studied.The research will focus on the following aspects:As the air spindle system has complex system characteristics,the spindle is simplified into a mass spring damping model.Based on Newton's second law and Euler angle momentum theorem,combined with the transformation of coordinate system,the 5 degree of freedom Newton Euler dynamic equation of air spindle rotor vibration is established by combining the transformation of coordinate system.The Simulink library of Matlab software is used to simulate the Newton Euler equation of air spindle rotor,and the displacement signals of the rotor under the idle state and the external force are analyzed.The standard rod is used as the measurement object of air spindle.The spindle vibration is measured based on the ultra precision axis measurement method,and the mathematical statistics method is adopted as the separation method of the standard bar shape error.The measurement instrument of Laser Doppler Vibrometer with NI data acquisition card and LabVIEW software are used to build the measurement system of air spindle rotor vibration.Based on Matlab software,the improved CEEMDAN algorithm is used to separate the eccentricity error of the standard rod,and the displacement signal of air spindle rotor vibration is analyzed.The displacement of the spindle rotor is evaluated by the least square circle method.Finally,the validity of the air spindle dynamic model is verified by the experimental data.To explore the influence of the air spindle dynamic response on the machining quality,a brass rod is used as the machining object and the Taylor Hobson Form Talysurf PGI 830 is used for roughness measurement equipment in the thesis.The influence of air spindle speed on the machining quality of the brass rod's end face and outer surface is studied when the feed speed and the cutting depth are constant.