A five-axis CNC machining instruction point interpolation method based on tool attitude control

Abstract

The invention provides a five-axis numerical control machining instruction point interpolation method based on tool attitude control, and relates to the field of numerical control machining. Including: obtaining tool tip position set P and tool axis vector set Q; obtaining parameter spline curve P(u); establishing local rotating coordinate system Q 0 ‑N‑V; get the tool axis vector curve Q(u); determine the included angle ψ k The parameter value u corresponding to the included angle k ; Determine parameter value u k The first and second order derivatives at the corresponding points; construct the curve ψ(u) that satisfies the second order continuity and determine the corresponding parameter values ​​of the kth interpolation cycle interpolation point; obtain the interpolation point and the corresponding tool axis vector of the next interpolation cycle . The present invention provides a five-axis numerical control machining command point interpolation method based on tool attitude control, which avoids the nonlinear error caused by the change of the rotation axis in the linear interpolation method, improves the machining accuracy, and avoids the distortion of the rotation axis of the machine tool. Great changes to improve the smoothness of the machined surface.

Description

Technical field [0001] The present invention relates to the field of CNC machining, and more particularly to a five-axis digital control processing instruction point interpolation method based on tool attitude control. Background technique [0002] The five-axis CNC machine is capable of flexible control of the tool bit position by the change of the knife point position coordinates and the knife shaft vector, thereby improving the processing speed, accuracy and surface finish, widely used in aviation, cars, mold manufacturing and other industries. The instruction point interpolation has a direct impact on machining accuracy and efficiency, and is a key issue in five-axis digital control processing. [0003] Linear interpolation is a commonly used instruction point interpolation method for a five-axis CNC system, which is linearly divided by the minority position coordinates of the machine tool, and the tool position is rotated. In actual processing, the linear interpolation can r...

AI Technical Summary

Problems solved by technology

First of all, the geometric shape of the five-axis CNC machining workpiece is complex. Using straight line segments to discretize complex curves will not only increase the burden of data transmission, but also generate unnecessary errors during the discretization process.

Secondly, due to the non-linear mapping between the components of the tool axis vector and the position coordinates of the rotary axis, the tool attitude cannot be controlled when the linear interpolation method is used for five-axis CNC machining

Finally, the linear interpolation method cannot guarantee the continuity of the speed and acceleration of each axis of the machine tool, which affects the smoothness of the machined surface

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