关键词: 数字孪生, 数控机床, 进给系统, 轮廓误差, 误差抑制

Abstract: It is difficult to control the contour error in high-speed and high-precision machining with(Computer Numerical Control,CNC)machine tools.Aiming at this problem,a Digital Twin (DT) based contour error reduction method was proposed.As a key executive component of CNC machine tools,the multi-axis feed drive system was taken as the specific object to elaborate a closed-loop technology framework of “modeling-prediction-control” for contour error reduction.In view of the multi-attribute and cross-coupling characteristics of the multi-axis feed system,its high-fidelity DT model was established.Through the transmission of the multi-granular information between the digital and physical spaces,the DT and physical entity could be accurately synchronized in different dimensions and various time-scales.With the reduced-order characterization of the DT model,the dynamic relationship of the contour error and its multi-influencing factors was modeled,and the dynamic estimation of the contour error was realized with the integration of the multi-granularity information.Based on the dynamic estimation result of the contour error,a comprehensive suppression method of the contour error was proposed to realize the interpolation control of the multi-axis feed drive system with time-varying motion control parameters.The synchronous motion experiment of the digital and physical spaces was conducted in a small three-axis CNC machine tool,and the effectiveness of the proposed method was verified.

Key words: digital twin, Computer numerical control machine tool, feed drive system, contour error, error reduction