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

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.