Concept and experimental validation of piezoelectric motor–based acceleration sensor in shock environment

In traveling-wave rotary piezoelectric motor, the ring-shaped piezoelectric sheet is divided into three parts: group A, group B, and single-electrode. Single-electrode offers auto frequency tracking signal to maintain speed stability of motor in traditional applications. In ammunition system, it is necessary to identify the launching environment and service processing environment with sensors. During the process of applying ultrasonic motor to ammunition system, a novel concept that single-electrode can be used as acceleration sensor is proposed. The theoretical analysis and experimental verification of this concept are carried out in this article. The theory shows the charge Q in single-electrode is proportional to the amplitude of acceleration when the frequency of acceleration is much less than the resonance frequency of stator. Theoretical and experimental results also indicate that there are interference signals from single-electrode in shock environment. So a conditioning circuit is designed to eliminate useless signal. Calibration experiment results show that single-electrode has a good linear output characteristic in shock environment, which proves the feasibility of single-electrode acceleration sensor. The sensitivities of single-electrodes in two tested stators are 4.5 and 3.88 mV/g respectively. The research achievements realize the function expansion of single-electrode and promote the application of piezoelectric motor in shock environment.