In-situ Monitoring for Thermal Errors of CNC Machine Tools Based on Digital Twin
With the rapid development and application of intelligent manufacturing,requirements of high precision,high speed and intelligence are put forward for CNC machine tools.However,the thermal deformations generated by the high-speed running of CNC machine tools seriously affect the machining accuracy;and thermal error control becomes the research hotspot.In order to improve the prediction accuracy of thermal errors of CNC machine tools,an in-situ monitoring method for thermal errors is proposed based on digital twin.The grating and eddy current displacement sensors are used to detect the thermal errors in the moving axes.A digital twin system is designed and developed based on real-time correction of thermal boundaries to simulate the thermal errors of the rotational axis and the workpiece through background calling ANSYS using VB.A comprehensive mathematical model for thermal errors is established based on homogeneous coordinate transformation.The thermal errors of current position are calculated in real time according to the measured and simulated thermal errors.An error growth-based thermal error prediction algorithm is constructed to automatically calculate the thermal errors of the target position through calling the EXCEL using the VB.And the in-situ monitoring of thermal errors is achieved in CNC machine tools.Experimental results show that the prediction accuracy of digital twin-based in-situ monitoring for thermal errors reaches 95％,which provides a basis for error compensation of CNC machine tools.
digital twinthermal errorsin-situ monitoringCNC machine tool
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