A Method of Interpolation Command Evaluation Based on Attenuation Magnification of Servo Feed System

Abstract

An interpolation command evaluation method based on the attenuation and magnification of the servo feed system. The numerical control system collects the command position sequence output to the servo feed axis of the machine tool, obtains the corresponding command position time-frequency diagram through the time-frequency transformation method, and extracts each command position. The corresponding spectrum curve is obtained from the section of the time-frequency diagram at all times; the frequency spectrum diagram is drawn through the closed-loop transfer function of the servo feed system, and converted into an attenuation magnification diagram and a magnification function; the frequency spectrum curve of each section of the time-frequency diagram according to the command and the multiplying function, thereby obtaining the output curves of the decayed output of the servo feed system at different times; finally, according to the difference between the two curves at different times, calculate the curve of the proportion of the decayed part of the command by the servo system relative to the original command over time, In this way, the magnitude of the following errors at different times, ie, different tool path positions, can be reflected; the present invention can accurately reflect the following precision.

Description

technical field [0001] The invention belongs to the technical field of numerical control machine tools, in particular to an evaluation method for interpolation commands based on the attenuation magnification of a servo feed system. [0002] technical background [0003] The instruction is the output of the interpolation operation of the CNC system and the input of the servo feed system. In order to ensure the following accuracy of the servo feed system of each axis, the command needs to be fully responded by the servo feed system; but in fact, due to the phase lag and amplitude attenuation of the command by the servo feed system, the servo feed system often cannot Responds perfectly to commands, causing following errors. [0004] In order to analyze whether the command can be responded by the servo feed system, and to reflect the ability of the servo feed system to achieve follow-up accuracy under a certain command input, a Chinese patent (publication number CN109085799B) di...

AI Technical Summary

Problems solved by technology

[0006] However, in essence, the command frequency components higher than the feed axis position loop bandwidth a will be attenuated by the servo feed system, but will not be completely attenuated; the command frequency components higher than the feed axis position loop bandwidth a will also be attenuated by the servo The possibility of feed system amplification, the above assumptions 1) ignore the impact of these two situations on the following accuracy

In addition, assumption condition 2) completely truncates the command frequency component higher than the command bandwidth b, which will cause a truncation error and affect the reflection effect of the following accuracy

Therefore, these two assumptions lead to the change curve of the proportion of the high frequency band of the command speed over time, that is, the change curve of the tool path, which can only approximately reflect the ability of the command to achieve the following accuracy, but cannot accurately reflect the following accuracy

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