Microelectromechanical gyroscope with fully differential structure and pitch/roll sensing
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Solution Overview
Problem
Existing microelectromechanical gyroscopes face challenges in maintaining scale factor stability and vibration rejection, particularly for rotations around pitch or roll axes, due to deformations caused by external factors like temperature variations and mechanical stress, which affect the accuracy of measurements.
Innovation Solution
A microelectromechanical gyroscope with a fully differential structure that includes transduction and sensing masses oscillating along specific axes, connected by motion conversion flexures that convert out-of-plane motions into in-plane motions, ensuring phase-opposition movements and enhancing sensitivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If out-of-plane sensing structure is used for pitch/roll axis gyroscopes, then the gyroscope can sense rotations around pitch or roll axes, but the sensitivity is lower compared to in-plane sensing structures
Solution Approach 1:
The patent applies dimensionality change by converting out-of-plane motion (perpendicular to support body) into in-plane motion (parallel to support body) through motion conversion flexures. This allows the sensing structure to maintain the adaptability of out-of-plane configuration for pitch/roll sensing while achieving the higher sensitivity characteristic of in-plane structures through the differential electrode arrangement.
2Reliability
If fully differential sensing architecture is used, then scale factor stability and vibration rejection are improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the sensing system into multiple independent sensing electrodes (first and second sensing electrodes) that are differentially coupled to each movable sensing electrode. This segmentation enables the fully differential architecture that improves scale factor stability and vibration rejection while the modular electrode design helps manage the inherent complexity through systematic arrangement.
3Reliability
If fixed sensing electrodes are placed at short distance from movable sensing electrode, then the effects of support body deformations are reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by creating localized differential sensing regions where pairs of fixed sensing electrodes are positioned close to each movable sensing electrode. This local differential configuration effectively compensates for support body deformations in each sensing region. The systematic local arrangement across multiple electrodes helps manage manufacturing precision requirements through consistent geometric patterns.
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
The gyroscope improves scale factor stability and vibration rejection by converting out-of-plane motions into in-plane motions, effectively rejecting common-mode contributions and maintaining accuracy under external stress, thus enhancing performance for pitch and roll axis rotations.
Implementation Method 1
motion conversion flexures, each motion conversion flexure connecting one of the plurality of transduction masses to one of the plurality of sensing masses and configured to convert movements of the one of the plurality of transduction masses along the third axis into movements of the one of the plurality of sensing masses along the second axis
Data Source
AI summary
A microelectromechanical gyroscope includes a support body having a main surface parallel to a reference plane defined by a first axis and a second axis perpendicular to each other. Transduction masses are constrained to the support body so as to be capable of oscillating along a driving direction parallel to the first axis and along a third axis perpendicular to the first axis and the second axis. Sensing masses are constrained to the support body at a distance from the substrate so as to be capable of oscillating in a direction parallel to the second axis. Motion conversion flexures connect the transduction masses to respective sensing masses and are configured so as to convert movements of the transduction masses along the third axis into movements of the respective sensing masses along the second axis.