A Review of Symmetric Silicon MEMS Gyroscope Mode-Matching Technologies

Abstract

The symmetric MEMS gyroscope is a typical representative of inertial navigation sensors in recent years. It is different from the traditional mechanical rotor gyroscope in that it structurally discards the high-speed rotor and other moving parts to extend the service life and significantly improve accuracy. The highest accuracy is achieved when the ideal mode-matching state is realized. Due to the processing limitation, this index cannot be achieved, and we can only explore ways to approach this index continuously. This paper’s results of error suppression for the symmetric MEMS gyroscope are initially classified into three categories. The first category mainly introduces the processing structure and working mode of the symmetrical gyroscope. The second is mechanical tuning from the structure and the third is electrostatic tuning from the peripheral control circuit. Based on the listed results, the paper compares the two tuning modes and analyzes their advantages and disadvantages. The fourth category is the tuning means incorporating the emerging algorithm. On this basis, the elements of improvement for future high-precision symmetric MEMS gyroscopes are envisioned to provide a part of the theoretical reference for the future development direction of sensors in inertial navigation.

Recent Advances in MEMS-Based 3D Hemispherical Resonator Gyroscope (HRG)—A Sensor of Choice

“…When the angle is measured, it is operated in whole angle (WA) or rate-integrating, gyroscope (RIG) mode. If the rotation rate is measured, it is operated in force rebalance (FR), rate gyroscope (RG), or amplitude modulator (AM) mode [ 65 ]. The stability of the scale factor and the wide bandwidth and range of measurement, together with direct measurement of angle, are advantages of a RIG [ 66 , 67 ].…”

“…Electrostatic types of electrode for driving (excitation) and capacitive electrodes for sensing (detection) are the most general form of electrodes used in Coriolis vibratory gyroscopes (CVGs). Angular vibration, line vibration and standing wave vibration are primary forms of electrostatic excitation, while angular vibration and line vibration are the main capacitive detection structural forms [ 65 ]. Thus, various combinations of drive-sense mode can be used.…”

Design and dynamic analysis of a highly sensitive MEMS gyroscope based on mode localization

“…Traditional MEMS gyroscopes with one degree-offreedom (1DOF) driving mode and sensing mode mainly rely on the mode matching in the driving and sensing directions, as well as a high quality factor to improve the sensitivity of the device [10][11][12][13]. It is to be noted that mode matching structures with a high quality factor usually have extremely low-frequency bandwidths, which limits the application of high-sensitivity MEMS gyroscopes.…”

Design and analysis of mode-matched decoupled mass MEMS gyroscope with improved thermal stability

“…One of the challenges in designing MEMS gyroscopes is to achieve mode matching, which means that the drive and sense mode frequencies are equal. Mode-matching can improve the sensitivity and accuracy of the gyroscope while reducing the noise and drift [16]. However, due to fabrication limitations and environmental factors, mode mismatch is inevitable in MEMS gyroscopes [17].…”

“…Mode mismatch can cause a reduction in the amplitude response of the gyroscope, reduced scale factor, and increased quadrature error [18]. To overcome mode mismatch, various methods have been proposed, such as mechanical tuning [16], electrostatic tuning [15][16][17][18][19][20], novel electrostatic non-uniform varied finger length tunable combs in mechanical resonators [21], feedback control [20], and algorithmic compensation [20,22,23]. Mechanical tuning involves modifying the structure or mass of the gyroscope to adjust the frequencies.…”