A Novel Compensation Method for Eliminating Precession Angular-Rate Bias in MEMS Rate-Integrating Gyroscopes

Jing Liu,Feng Bu,Lin Xuan,Yinghui Yang,Bo Fan,Dacheng Xu,Shuwen Guo

doi:10.1109/access.2020.3014661

Jing Liu, Feng Bu + Show 5 more

Open Access

https://doi.org/10.1109/access.2020.3014661

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Journal: IEEE Access	Publication Date: Jan 1, 2020
Citations: 5	License type: CC BY 4.0

Affiliation: Soochow University, University of South China

Abstract

The structural asymmetry of the MEMS rate-integrating gyro (RIG) mode produces a threshold and an angle-dependent bias (ADB) that cause gyroscopes operating in this mode to stop working at input rates below the threshold and degrade the linearity of the output angle. This defect in the RIG output angle is actually caused by a precession angular-rate bias that results from both damping asymmetry (anisodamping) and stiffness asymmetry (anisostiffness). This paper describes a novel compensation method based on Fourier series fitting combined with a multiple iteration technique. The proposed compensation method can significantly reduce both the input rate threshold and ADB. Simulations indicate that the threshold and ADB caused by anisodamping and anisostiffness can be reduced by three orders of magnitude. An experimental application of this method produced a MEMS RIG threshold as low as 0.05° per second, representing an improvement of two orders of magnitude and lower than has previously been reported.

Highlights

MEMS gyroscopes can operate in both rate gyro (RG) mode and rate-integration gyro (RIG) mode
The above methods can reduce both the threshold and angle-dependent bias (ADB) to some extent, but they cannot fundamentally solve the problem of precession angular-rate bias errors introduced by the structural asymmetry of the gyro
In this paper, we have proposed a novel method for precession angular-rate bias error compensation in an attempt to reduce the threshold and ADB of RIG

Summary

INTRODUCTION

MEMS gyroscopes can operate in both rate gyro (RG) mode and rate-integration gyro (RIG) mode. The above methods can reduce both the threshold and ADB to some extent, but they cannot fundamentally solve the problem of precession angular-rate bias errors introduced by the structural asymmetry of the gyro. To completely eliminate precession angular-rate bias errors, this paper introduces a novel compensation method based on a Fourier series fitting combined with a multiple iteration technique. This paper first presents a derivation of the theoretical formulas from the relevant dynamic equations, and adds precession angular-rate bias terms associated with the damping and stiffness anisotropy. It can be seen that the bias terms result in some problems, such as a threshold and ADB Through these three control loops, the feedback forces Fx and Fy in the x and y modes can be generated using: Fx

FE cos θ sin ωt

Findings

CONCLUSION