A Self-Test Method for MEMS Gyroscope With Equivalent Inertial Force

Abstract

This article introduces a self-test approach for micro-electromechanical system (MEMS) vibrating gyroscopes based on the concept of equivalent inertial force. By applying electrostatic signals to the feedback electrode, it is possible to simulate the inertial force input, enabling measurement of the gyroscope scale factor (SF) without reliance on physical testing equipment. This article presents the operational principle of equivalent inertial force, establishes the correlation between equivalent inertial force and angular velocity through derivation, and accomplishes the calibration of this relationship across a broad temperature range using quadrature feedback forces. In contrast to traditional methods, this approach facilitates direct measurement of the SF of the gyroscope and compensates for variations in the SF induced by alterations in the temperature and environmental conditions. The efficacy of the proposed approach was validated in a comparative experiment on a ring resonator gyroscope. In the open-loop mode, the average calibration error of the SF of the equivalent inertial force method and the turntable method is 5.608%. The long-term self-test repeatability is 1781.2 ppm. Furthermore, the SF self-compensation of the gyroscope within the temperature range of $- 20~^{\circ }$ C to $+ 40~^{\circ }$ C was achieved using the self-test results. The temperature sensitivity of the SF before and after compensation changed from 6689.7 ppm/°C to 318.6 ppm/°C, which was reduced by $20\times $ .