Triaxial numerical control machine tool space error prediction method based on error field feature points

Abstract

The invention discloses a numerical control machine tool space error prediction method based on error field feature points. The method comprises the steps of: a. measuring three motion axis errors andperpendicularity errors of a machine tool to obtain a triaxial error data item; b. calculating three items of errors of a machine tool error field feature point space according to the triaxial errordata, and storing the three items of errors in a numerical control system; and c. predicting a machine tool space non-feature point error compensation value according to the error data of eight vertexfeature points of a cube. According to the method, the three motion axis errors and the perpendicularity errors of the machine tool are measured, the three items of errors of the spatial feature points of the machine tool are obtained through calculation according to the triaxial error data, and the errors of any positions of non-feature points located in the cube are predicted according to errordata of the eight vertex feature points of the cube. The method has the advantages of being small in measurement data size, small in calculation amount, high in compensation real-time performance, reliable in precision and the like.

Description

technical field [0001] The invention relates to the technical field of numerical control, in particular to a spatial error prediction method of a three-axis numerical control machine tool based on error field feature points. Background technique [0002] A three-axis CNC machine tool includes three linear motion axes, and the machine tool produces errors due to manufacturing and assembly. The rigid body has 6 degrees of freedom in space, so each linear motion axis has 6 error elements in space, that is, 3 movement errors and 3 angle errors, a total of 18 errors in the three axes, plus two and two of the three axes 3 items of squareness errors caused by not being perfectly vertical, so a total of 21 items of errors. At present, the relatively mature error compensation method adopts the single-axis error compensation method, that is, the error items of the three motion axes of the machine tool are respectively compensated, including the verticality error compensation, but bec...

AI Technical Summary

Problems solved by technology

The patent "A Method for Measuring the Space Error of the Full Stroke of a Machine Tool" proposes a method for directly measuring the error of the full working space of the machine tool. However, the installation of the measuring instrument has very strict requirements on light, and at the same time, it is limited by the structure of the machine tool. These reasons greatly limit its Application and promotion; At the same time, through literature search, it was found that there are a large number of literatures that use the homogeneous coordinate transformation to directly calculate the three-axis error data of the CNC machine tool, thereby obtaining the error of any position in the machine tool space. The amount of interpolation calculations in the process is too large, which leads to an excessive burden on the system, and it is difficult to apply it to the CNC system for real-time compensation. Therefore, the patent "Real-time Compensator for CNC Machine Tool Errors Based on the Offset of the External Coordinate Origin of the Machine Tool (CN105700472A)" proposes to use plug-in The compensator independently calculates the compensation value of the machine tool space error through the compensator calculation module, and sends it to the CNC system for real-time compensation. However, due to problems such as interface with the CNC system and communication lag, it is still difficult to be applied in practice.

Images