Method for interpolating curve with variable interpolation cycle on basis of interpolation precision and limitation of accelerations

Abstract

A method for interpolating a curve with a variable interpolation cycle on the basis of interpolation precision and control on maximum accelerations of various driving shafts of a machine tool includes operating steps of (1), approximating the curve to be interpolated by large quantities of small linear segments similar to the interpolation step length on the basis of the set interpolation precision so that approximation errors among the small linear segments and the curve to be interpolated meet requirements of the interpolation precision; and (2), determining the interpolation cycle of each small linear segment and the quantity of the interpolation cycles according to the programming speed, the maximum accelerations of the driving shafts of the machine tool and limitation of an interpolation cycle range of a numerical control system. The method has the advantages that data transmission quantity is reduced, the interpolation precision is guaranteed, the machining efficiency is improved, computational complexity of curve interpolation is reduced effectively, and ,machining errors caused by vibration of the machine tool when the speed of the machine tool is increased or decreased suddenly are reduced; interpolation can be carried out according to the set interpolation precision and the power performance of the machine tool, and the method is particularly suitable for precision machining; and backtracking processing is omitted, the computation speed is high, the performance is stable and reliable, and real-time machining requirements are met.

Description

technical field [0001] The invention relates to a curve interpolation method with variable interpolation period based on the interpolation accuracy and the maximum acceleration control of each driving shaft of the machine tool for a numerical control machine tool, and belongs to the technical field of digital control processing of the numerical control machine tool. Background technique [0002] When CNC machine tools process complex surfaces, they usually perform linear interpolation by approaching curves from a large number of small straight line segments within the set machining accuracy range. However, the disadvantage of using the linear interpolation method is that the amount of data is large and the processing efficiency is low. In order to improve machining efficiency and machining quality, curve interpolation is currently a research hotspot in the field of NC machining interpolation technology. However, due to the high computational complexity of curve interpolation...

AI Technical Summary

Problems solved by technology

[0004] 1. The isoparameter curve interpolation method has low computational complexity, but because the interpolation step length of the isoparameter curve interpolation is not uniform, it is easy to cause frequent acceleration and deceleration, which will cause vibration of the machine tool, and the machining accuracy cannot be guaranteed.

[0005] 2. The constant rate curve interpolation method has relatively low computational complexity, but it is easy to cause relatively large machining errors in the sharp part of the curve. At the same time, due to the change of the speed direction, it is also easy to cause frequent acceleration of each drive axis of the machine tool. slow down

Although this method can obtain the optimal processing speed curve, the calculation complexity for complex curves is very high, and it is difficult to apply to actual NC machining. At the same time, the processing error is not considered, and the processing accuracy is difficult to be guaranteed.

Images