Synchronized Multi-Axis Gyroscope With Ringlike Synchronization Element

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Solution Overview

Problem

Multi-axis gyroscopes face challenges in achieving robustness and accuracy due to external vibrations and the complexity of proof mass arrangements, which can lead to undesired oscillations and interference between oscillation frequencies, making it difficult to design a simple yet effective multiaxis gyroscope with one oscillation frequency for all proof masses.

Innovation Solution

The design incorporates a ringlike synchronization element that connects proof mass pairs with a central symmetry point, allowing flexible anti-phase oscillation modes while resisting cophasal oscillation modes, and utilizes torsion bars and suspension arrangements to maintain desired oscillation frequencies and prevent undesired oscillations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple proof masses are used for multi-axis measurement, then measurement capability is improved, but device complexity and susceptibility to external vibrations increase

Engineering Contradiction:
Improvemulti-axis measurement capabilityVSAvoidproof mass arrangement complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple proof masses (first and second proof mass pairs) into a single integrated structure with common suspension elements. The proof masses are mechanically coupled through shared suspenders and a connection structure, allowing them to oscillate in a coordinated manner. This merging approach enables multi-axis measurement capability while reducing overall device complexity compared to using separate, independent proof mass systems for each axis.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The proof mass structure is designed to perform multiple functions simultaneously: the first proof mass pair measures rotation about one axis while the second proof mass pair measures rotation about another axis. The common suspension system serves both measurement functions, and the structure can detect angular velocity components along multiple axes using the same physical elements, thereby achieving multi-functionality without proportionally increasing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If proof masses are suspended flexibly for desired oscillation modes, then oscillation amplitude is improved, but susceptibility to undesired oscillation modes increases

Engineering Contradiction:
Improveoscillation amplitudeVSAvoidundesired oscillation from external vibrations
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The suspension system exhibits different mechanical properties for different oscillation modes: it is designed to be flexible in the directions corresponding to desired oscillation modes (allowing large amplitude motion) while being stiff in directions corresponding to undesired oscillation modes (suppressing unwanted motion). This local differentiation of mechanical properties enables the system to simultaneously achieve large oscillation amplitudes for measurement while resisting external vibrations that would cause erroneous signals.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The suspender structure is designed with asymmetric stiffness characteristics, being softer in specific directions that permit the desired oscillation modes while being harder in other directions that would permit undesired modes. This asymmetric design creates a directional dependence of the suspension flexibility, allowing the proof masses to oscillate freely in measurement-relevant directions while being constrained in directions where external vibrations would interfere.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If proof masses oscillate in anti-phase, then robustness to external vibrations is improved, but synchronization complexity increases

Engineering Contradiction:
Improverobustness to external vibrationsVSAvoidsynchronization structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a common suspension system that mechanically couples the proof masses in such a way that anti-phase oscillation is naturally encouraged. The shared suspenders and connection structure create a mechanical configuration where motion of one proof mass in one direction is directly coupled to opposite motion of another proof mass, thereby achieving synchronization through mechanical coupling rather than complex active control systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The suspension structure is designed to automatically synchronize the proof masses into anti-phase oscillation through its inherent mechanical properties. The geometry and stiffness distribution of the suspenders create a self-synchronizing effect where the system naturally evolves into the anti-phase mode without requiring external synchronization mechanisms or complex control algorithms, thereby achieving robustness while minimizing added complexity.

Inventive Principle:
Principle #25Self-service

4Device complexity

If a single oscillation frequency is used for all proof masses, then device simplicity is improved, but interference between measurement modes may increase

Engineering Contradiction:
Improveoscillation frequency managementVSAvoidmeasurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the measurement function across multiple proof mass pairs that all oscillate at the same frequency, but each pair is oriented and suspended to measure different rotational axes. By dividing the measurement task into separate spatially-distinct proof mass pairs, the system can use a single oscillation frequency without mode interference, as each segmented element measures a different physical quantity (rotation about different axes) despite sharing the same oscillation frequency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent resolves frequency interference by moving the differentiation from the frequency domain to the spatial domain. All proof masses oscillate at the same frequency, but they are arranged in different spatial orientations and suspended to respond to different rotational axes. This dimensional separation allows simultaneous measurement of multiple axes using a single frequency, avoiding the interference that would occur if multiple frequencies were used.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 results in a simpler, more robust multiaxis gyroscope with improved accuracy and resistance to external vibrations, ensuring reliable operation by synchronizing proof mass pairs and maintaining desired oscillation modes, thereby enhancing the robustness and precision of angular velocity measurements.

Implementation Method 1

The gyroscope also comprises first and second x-axis torsion bars which extend along the x-axis from the first ringlike body to the first and second proof masses which form the first proof mass pair, and first and second y-axis torsion bars which extend along the y1-axis from the first ringlike body to the third and fourth proof masses which form the second proof mass pair

Methodology Applied
Scientific EffectTorsion: Torsion Spring

Implementation Method 2

The suspenders are configured to flexibly allow oscillating primary motion and secondary motion at a desired resonant frequency

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

Microelectromechanical gyroscopes use the Coriolis effect to measure angular velocity. In oscillating MEMS gyroscopes, an object is driven into oscillating movement by an actuating drive force

Methodology Applied
Scientific EffectCoriolis force: Coriolis Force

Implementation Method 4

If the gyroscope undergoes angular rotation, the Coriolis force generates a secondary oscillation mode in the oscillating object

Methodology Applied
Scientific EffectCoriolis effect: Coriolis Force

Data Source

PatentEP3671116B1Synchronized multi-axis gyroscope
Publication Date: 2021.11.17 MURATA MFG CO LTD
  • EP3671116B1 patent drawingFigure 1a~1b
  • EP3671116B1 patent drawingFigure 1c~1d
  • EP3671116B1 patent drawingFigure 1e~1f

AI summary

The disclosure relates to a microelectromechanical gyroscope which comprises first and second proof masses which form a first proof mass pair and third and fourth proof masses which form a second proof mass pair. The oscillation of the first and second proof mass pairs is synchronized by a synchronization element which comprises a ringlike body and torsion bars which extend along the x-axis from the ringlike body to the first, second, third and fourth proof masses.