Research On Thermal Error Compensation And Experiment For Large Gear Measuring Center

Large gear measuring center is a kind of high precision measuring equipment based on electronic generating method. However, the thermal deformation of this large equipment caused by temperature changes will result in large measurement error. Therefore, aiming to reduce thermal error due to temperature changes, this thesis further studies the effect on measurement accuracy caused by temperature changes based on the geometric error compensation technology of CNC gear measuring center, researches and compensates for the thermal error by means of thermal error compensation technology, which provides the foundation and theoretical basis for improving measurement accuracy, design and measurement of gear measuring center.This thesis introduces the research status on thermal error compensation technology of gear measuring center at home and abroad, analyzes the thermal characteristics according to the structural characteristics of gear measuring center, and analyzes the heat resource and the variation rules of thermal deformation. And on that basis, it uses ANSYS to conduct the thermal-structural coupling finite element simulation analysis, analyzing its thermal deformation size and position disciplines. In order to measure the temperature and thermal deformation, a temperature and thermal error measuring system is set up, which includes measurement equipment, measurement solution and data acquisition systems.In order to research the relationship between temperature changes and thermal deformation, an empirical thermal error model is built up by experimental modeling method in this thesis. The model firstly conducts the group and optimization of the temperature measurement points using fuzzy clustering method to find the key temperature measurement points on gear measuring center. And then it builds up the thermal error model using artificial neural network and multiple regression methods. On the basis of the optimization theory, the thermal error modeling system is established by integrating the process into a thermal error compensation software. To reduce the thermal error, the software compensation method is proposed and its compensation process is developed. Then the error compensation can be realized by coordinate calculation method according to the coordinate calculation principle of the gear deviation parameters.Furthermore, the thermal error compensation experiment platform is set up to verify the thermal compensation model. By applying the thermal error compensation method to the experiments, the key temperature measurement points are determined and the thermal error model is established. And the multiple linear regression model is applied to the experiments to calculate the tooth profile deviation and helix deviation and compensate the thermal error for the involute master of gear. Eventually, the error decreases greatly after compensation judging from the experimental results, which shows that the thermal error compensation model can improve the accuracy of measurement significantly.