A Double Closed-loop Compensation Method for Five-Axis Machining Trajectory Contour Error

Abstract

The present invention provides a five-axis machining track contour error double closed-loop compensation method, belongs to the multi-axis numerical control process technology field, and relates to a contour error double closed-loop compensation method configured to improve the five-axis machining precision based on inner ring prediction compensation and outer ring feedback compensation of contour errors. Based on model prediction and feedback correction, the method estimates motion position of each physical axis at the next moment, employs tangential inversing and the Newton's method to calculate tip point contour errors and cutter axis direction contour errors of the next moment and the current moment, and the contour errors are subjected to prediction compensation at the inner ring and the contour errors are subjected to prediction compensation at the outer ring according to inversed Jacobian matrix so as to improve the five-axis machining track contour precision. The five-axis machining track contour error double closed-loop compensation method inhibits the residual errors caused by outside disturbance and model errors on the basis of realizing control of the five-axis machining contour errors in advance so as to have important meanings for improving the five-axis numerical control machining precision.

Description

technical field [0001] The invention belongs to the technical field of precise, efficient and intelligent multi-axis numerical control machining, and relates to a double-closed-loop compensation method for contour error for improving the precision of five-axis numerical control machining. Background technique [0002] In the process of multi-axis linkage contour tracking motion, due to the existence of factors such as single-axis servo control system follow-up error, multi-axis control system dynamic mismatch and external disturbances, there will be deviations between the actual motion trajectory and the ideal motion trajectory, that is, the contour error . How to reduce the contour error so as to improve the accuracy of multi-axis linkage contour tracking is a huge challenge for the development of multi-axis CNC systems. For three-axis CNC machining, due to the unique direction of the tool axis, there is only the contour error of the tool tip point motion trajectory. Howe...

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Problems solved by technology

[0003] Prior art document 1 "Pre-compensation of contour errors in five-axis CNC machine tools", Zhang et al., International Journal of Machine Tools and Manufacture, 2013, 74: 1-11, this document predicts five-axis machining tools by solving differential equations Point contour error and tool axis direction contour error, and then pre-compensate the predicted error value, but this method is sensitive to system parameters and has poor anti-interference ability

Document 2 "A tool-path control scheme for five-axis machine tools", Chih-ChingLo, International Journal of Machine Tools and Manufacture, 2002, 42: 79-88, this document uses the position feedback values ​​of each axis to establish the contour error model, and through the real-time conversion between each drive axis and the coordinate system, the contour error feedback compensation is realized, but this method only compensates the contour error that has occurred, and cannot realize advance control before the contour error occurs

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