| Accuracy is an important measure of CNC machine tools performance. Which affect machining accuracy are mainly geometric errors, thermal error, force error and the machine control system error, at the same time geometric errors is a high proportion. This article focuses on CNC machine tools kinematics modeling, as well as research geometry error measurement methods and error identification model.Using a laser Doppler interferometer measure open CNC platform based on PC + PMAC.Combination of 12 line error identification model solves for 21 geometric error elements.While using MATLAB’s GUI module, designing error analysis software program with a graphical user interface.It contains the graph drawing function allowling users to analyze trends of positioning error, error identification procedure significantly reduces the time to calculate the overall error identification process.This paper combining machine kinematics theory and transformation matrix technique,derived CNC machine tools in the ideal state of motion and the actual motion state space transformation matrix.Based on low-order array described method, obtained CNC machine tool geometric error model. This paper has a detailed analysis of nine line method and twelve-line measurement and identification calculation process in geometric errors measurement.Taking into account the Doppler laser interferometer for linear positioning error in the measurement process is simple to set up, dimming fast,accurate measurements and other characteristics.Final selection is twelve lines, and draw error curve, according to the twelve-line method error model identified 21 elements of geometric errors.This paper based on the actual geometric error experimental measured and identification results analysis. This open CNC motion platform positioning error withinthe range of tens of microns, and in order to verify the reliability of the recognition result,the experiment was repeated measurements. |
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