Isotropic Attenuated Motion Gyroscope with Segmented Proof Mass
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Solution Overview
Problem
Microelectromechanical systems (MEMS) gyroscopes face challenges in efficiently detecting rotation due to limitations in attenuating motion of proof masses, which can lead to damage from large displacements and reduced signal-to-noise ratios, especially when trying to implement quadrature trimming electrodes with small gaps.
Innovation Solution
The implementation of a MEMS device with a proof mass that undergoes attenuated motion relative to shuttles, utilizing kinematic pivoting linkages and nested springs to control lever arm ratios and pivot points, allowing for efficient quadrature trimming and frequency tuning without damaging the device, and achieving mode-matched frequencies for improved signal-to-noise ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the proof mass is allowed to move with large displacement to improve sensing capability, then the signal-to-noise ratio is improved, but the device may be damaged from large displacements
Solution Approach 1:
The device is segmented into two distinct mass components: a shuttle mass that experiences large displacement for high signal-to-noise ratio, and a proof mass that experiences attenuated displacement to prevent damage. The lever arm mechanism divides the motion between these segments, allowing each to operate in its optimal displacement range.
Solution Approach 2:
The lever arm acts as an intermediary mechanism between the shuttle and proof mass. It transmits and transforms the motion from the shuttle to the proof mass with attenuation, enabling the proof mass to experience reduced displacement while still being coupled to the high-signal shuttle motion.
2Measurement precision
If quadrature trimming electrodes with small gaps are implemented to improve precision, then measurement precision is improved, but the device complexity increases
Solution Approach 1:
The quadrature trimming electrodes are positioned in the out-of-plane dimension rather than in-plane. This vertical placement allows for small gap distances between electrodes while maintaining isotropic operation, achieving high precision trimming without increasing in-plane structural complexity.
3Measurement precision
If mode-matched frequencies are achieved to improve signal-to-noise ratio, then measurement precision is improved, but the device complexity increases
Solution Approach 1:
The same set of electrodes serves multiple functions: primary drive, sense detection, quadrature trimming, and frequency tuning. By using electrodes disposed in openings of the proof mass for both quadrature trimming and frequency tuning, the device achieves mode-matched operation without adding separate tuning mechanisms, thereby reducing overall complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient quadrature trimming and frequency tuning while preventing damage from large displacements, significantly increasing the signal-to-noise ratio and allowing for isotropic operation without the need for ring designs, achieving up to 1,000 times better performance than mode-split MEMS devices.
Implementation Method 1
a first lever coupled to the first shuttle at a first end of the first lever and to the proof mass at a second end of the first lever; and an anchor coupled to the substrate, wherein the first lever is coupled to the anchor at a pivot point a first distance away from the first end of the first lever and a second distance away from the second end of the first lever
Implementation Method 2
the first distance is greater than the second distance such that displacement of the proof mass is attenuated relative to displacement of the first shuttle
Implementation Method 3
utilizing kinematic pivoting linkages and nested springs to control lever arm ratios and pivot points
Implementation Method 4
a first plurality of electrodes and configured to drive the first proof mass along the resonator axis
Implementation Method 5
a sense structure configured to move along a second axis substantially perpendicular to the resonator axis in response to motion of the proof mass along the resonator axis
Data Source
AI summary
According to some aspects, there is provided a microelectromechanical systems (MEMS) device wherein one or more components of the MEMS device exhibit attenuated motion relative to one or more other moving components. The MEMS device may comprise a substrate; a proof mass coupled to the substrate and configured to move along a resonator axis; and a first shuttle coupled to the proof mass and comprising one of a drive structure configured to drive the proof mass along the resonator axis or a sense structure configured to move along a second axis substantially perpendicular to the resonator axis in response to motion of the proof mass along the resonator axis, wherein displacement of at least a first portion of the proof mass is attenuated relative to displacement of the first shuttle and/or a second portion of the proof mass.