Modal parameters identification of micro motor rotor by sound

The existing modal parameters identification data of motor rotors generally is obtained by vibration sensors. Due to the influence of the additional mass of vibration sensors, there are significant errors in measuring micro motors. A method for identifying modal parameters of micro motor rotors based on acoustic signals is proposed in this paper, and the noise is depressed. This method collects acoustic signals by tapping the micro motor rotor and uses short-term energy integration to process acoustic signals in order to depress noise. We first establishes the theoretical basis for applying short-term energy integration to modal identification, determines the relationship between the slope of the inverse integration curve and the damping ratio, and then conducts modal simulation analysis on multi degree of freedom vibration noise signals to verify the correctness of the method. Finally, a hammering test was conducted on the rotor of the micro motor, and the method was verified for modal parameter identification.