Equal-chord-error variable-step tangent interpolation method

Abstract

The invention belongs to the field of a numerical control technology and especially relates to an equal-chord-error variable-step tangent interpolation method. The method is mainly used in multi-axis machining tool-path planning work, is suitable for surface curvature variable self-adaptative adjustment of machining step-length, realizes maximization of machining step-length within chord error range, can be used to obtain the fewest curve discretization segments and has high machining efficiency. By a new equal-chord-error step-length method, a tool path track is determined. Chord errors within each approximation line segment are uniform and consistent. Machining precision is high.

Description

technical field [0001] The invention belongs to the technical field of numerical control, and in particular relates to a tangent interpolation method with constant bow height error and variable step length, which is mainly used for multi-axis machining tool path planning operations. Background technique [0002] In recent years, due to its higher processing efficiency and better processing quality, five-axis machining has been used in the field of free-form surface (free-form surface refers to the curve whose surface shape cannot be continuously processed and has the arbitrary characteristics of traditional processing) parts manufacturing more and more widely. Most of the five-axis CNC machining of free-form surfaces currently uses commercial CAM software for auxiliary programming. Since the general CNC system only has the ability of spatial linear interpolation, the tool paths generated by the CAM software are composed of a large number of small straight line segments. Thi...

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Problems solved by technology

[0008] In order to solve the problems existing in the traditional method in multi-axis machining tool path planning step size calculation, the present invention proposes a tangent interpolation method with equal bow height error variable step size, which adapts to the change of surface curvature and adjusts the processing step size automatically to realize The maximization of the processing step within the tolerance range of the bow height can obtain the least number of discrete curve segments. At the same time, in order to improve the efficiency, we choose the bow height error to be equal to the bow height tolerance; adopt the new equal bow height error step size method The determined tool path trajectory, the bow height error in each approximation straight line segment is uniform, and the machining accuracy is high

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