Method for acquiring frequency response function of numerically-controlled machine tool based on cutting excitation

Abstract

The invention discloses a method for acquiring a frequency response function of a numerically-controlled machine tool based on cutting excitation. The method includes the steps that a machine tool structure is excited through random cutting force generated in a machine tool cutting project; vibration response signals of the position where the frequency response function needs to be acquired are measured through a sensor; a cutting force model is established, and the cutting force model is modified through a modification function according to the influence of the rotating speed change on the cutting force; coefficients in the cutting force calculation model are determined, and the modification function is fit according to experiments; the frequency response function of the machine tool structure is acquired according to the cutting force acquired through calculation and vibration response acquired through measurement, curve fitting is conducted on the frequency response function acquired through calculation, noise is eliminated, and then the final frequency response function is acquired. According to the method, dynamic characteristics of the machine tool with an accurate and reliable recognition result in an operating state can be acquired, and the optimization design of the machine tool structure and state monitoring of the machine tool can be conducted through the acquired frequency response function.

Description

technical field [0001] The invention belongs to the field of dynamic analysis of numerical control equipment structures, and in particular relates to a method for obtaining frequency response functions of numerical control machine tools based on cutting excitation. Background technique [0002] The dynamic characteristics of a machine tool are crucial to improving its machining performance and structural design. At present, the dynamic characteristics of the machine tool structure are mainly obtained based on the experimental modal analysis method of forced vibration. The main feature of this method is to apply a specific excitation force to the machine tool structure, and simultaneously measure the excitation force and the vibration response of the machine tool structure to obtain the frequency response function, and use the frequency response function to characterize the dynamic characteristics of the machine tool structure. [0003] However, the above method can only obt...

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Problems solved by technology

[0004] The working modal analysis method developed in recent years only identifies the modal parameters of the machine tool structure by measuring the vibration response of the machine tool structure in the working state. However, in the actual working modal analysis, since the input force is unknown, it cannot Direct access to the frequency response function of the machine tool structure

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