Frequency-modulated Gyroscope Research Articles

Frequency-Modulated MEMS Gyroscopes: A Review

As a high-precision angular rate sensor, the Frequency-Modulated (FM) gyroscope based on MEMS craft has attracted more and more attention in recent years, owing to its advantages in low power consumption, low temperature sensitivity, very high bandwidth, and excellent scale factor stability. This review summaries the history and latest development of the FM gyroscope research. The theory of the frequency modulation effect of the Coriolis coupling is provided based on the method of rotating wave approximation in a systematic and explicit way. Typical FM gyroscope operation modes, such as QFM, IFM, LFM, and their working principles are introduced minutely. The error sources of FM gyroscopes, and the characters comparison between FM and AM gyroscopes are discussed in detail as well.

Design and Optimization of a Novel SAW Gyroscope Structure Based on Amplitude Modulation with 1-D Phononic Crystals.

Surface acoustic wave gyroscopes (SAWGs), as a kind of all-solid-state micro-electro-mechanical system (MEMS) gyroscopes, can work normally under extremely high-impact environmental conditions. Among the current SAWGs, amplitude-modulated gyroscopes (AMGs) are all based on the same gyro effect, which was proved weak, and their sensitivity and intensity of the output are both lower than frequency-modulated gyroscopes (FMGs). However, because FMGs need to process a series of frequency signals, their signal processing and circuits are far less straightforward and simple than AMGs. In order to own both high-sensitivity and simple signal processing, a novel surface acoustic traveling wave gyroscope based on amplitude modulation is proposed, using one-dimensional phononic crystals (PCs) in this paper. In view of its specific structure, the proposed gyroscope consists of a surface acoustic wave oscillator and a surface acoustic wave delay line within a one-dimensional phononic crystal with a high-Q defect mode. In this paper, the working principle is analyzed theoretically through the partial wave method (PWM), and the gyroscopes with different numbers of PCs are also designed and studied by using the finite element method (FEM) and multiphysics simulation. The research results demonstrate that under a 1 V oscillator voltage output, the higher sensitivity of −23.1 mV·(rad/s)−1 in the linear range from −8 rad/s to 8 rad/s is reached when the gyro with three PC walls, and the wider linear range from −15 rad/s to 17.5 rad/s with the sensitivity of −6.7 mV·(rad/s)−1 with only one PC wall. Compared with the existing AMGs using metal dots to enhance the gyro effect, the sensitivity of the proposed gyro is increased by 15 to 112 times, and the linear range is increased by 4.6 to 186 times, even without the enhancement of the metal dots.

Fully Differential Single Resonator FM Gyroscope Using CW/CCW Mode Separator

This paper reports a fully differential frequency modulated (FM) gyroscope where the superposed clockwise (CW) and counter clockwise (CCW) modes are independently controlled on a single resonator. The CW and CCW mode detectors were developed to control both modes simultaneously on the resonator. A frequency and quality factor mismatch compensation method was developed to perfectly orthogonalize these two modes. A FM gyroscope operation with excellent linearity between applied angular rate and frequency difference was demonstrated. The temperature coefficient of scale factor was as small as −52 ± 136 ppm/°C. The scale factor and bias were stable over 700 hours with the drift less than 0.062 ± 0.100 ppm/hr and 31 ± 121 ppm/hr, respectively. [2018-0103]

A new MEMS three-axial frequency-modulated (FM) gyroscope: a mechanical perspective

Abstract Micro-Electro-Mechanical Systems (MEMS) gyroscopes are inertial sensors for the measurement of angular rates. They have a variety of applications from consumer electronics to drones and the need of stability against environmental fluctuations, such as temperature, is a key factor in order to avoid expensive calibration procedures. Frequency Modulation (FM) has been recently proposed as an innovative working principle for MEMS gyroscopes and as the desired solution in terms of stability against environmental fluctuations. In this paper, the FM working principle is formalized for the three-axial case for the first time and the governing equations are derived both in the idealized case of a point-mass gyroscope and in the real case of a distributed-mass gyroscope. Moreover, the mechanical structure of the first three-axial MEMS FM gyroscope is proposed and studied. Preliminary experimental measurements prove the validity of both the model and the simulations results employed during the design process. The proposed structure overcomes lots of the constraints of the surface micromachining fabrication processes and represents an important step towards the development of a new class of MEMS gyroscopes.