Multiaxis Gyroscope Synchronization Frame Vibration Isolation

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Solution Overview

Problem

Multiaxis microelectromechanical gyroscopes face challenges in robustness against external disturbances, particularly in suppressing vibrations and isolating oscillation modes, which affects the accuracy of angular rotation measurements.

Innovation Solution

The use of a proof mass quartet and a detection mass quartet, synchronized by a frame with lateral and transversal corner springs, allows for decoupling of primary and secondary oscillation modes, ensuring that detection masses remain stationary during primary oscillation and only respond to secondary oscillations induced by angular rotation, effectively isolating external vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single oscillating proof mass is used, then the device complexity is reduced, but the robustness against external vibrations deteriorates

Engineering Contradiction:
Improveproof mass configurationVSAvoidrobustness against external vibrations
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The single proof mass is segmented into four separate proof masses arranged symmetrically around a center point. This segmentation allows the system to distinguish between common-mode vibrations (affecting all masses equally) and differential-mode vibrations (affecting masses differently), thereby improving robustness against external vibrations while maintaining manageable complexity through modular architecture

Inventive Principle:
Principle #1Segmentation

2Reliability

If two or four proof masses oscillating in anti-phase are used, then the robustness against external vibrations is improved, but the device complexity increases

Engineering Contradiction:
Improverobustness against external vibrationsVSAvoidproof mass configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The four proof masses are merged into a unified oscillating system driven by a single drive actuator. The symmetric arrangement and coupling mechanism allow all four masses to oscillate in anti-phase simultaneously, creating a cohesive system that achieves vibration robustness through collective behavior rather than requiring four independent actuators or complex control systems

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the cophasal resonant frequency is brought above 50 kHz, then the robustness to external vibrations is improved, but the measurement precision deteriorates

Engineering Contradiction:
Improverobustness to external vibrationsVSAvoidangular rotation measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The coupling between proof masses is engineered to create different local oscillation characteristics. The anti-phase oscillation mode is specifically designed to be sensitive to angular rotation while the cophasal mode is designed to be insensitive to external vibrations. This local differentiation of oscillation quality allows the system to achieve both vibration robustness and measurement precision by selectively detecting the appropriate mode

Inventive Principle:
Principle #3Local quality

4Adaptability or versatility

If multiple one-axis gyroscopes are incorporated for different axes, then the measurement capability for multiple axes is improved, but the device complexity and electronic circuit design difficulty increase

Engineering Contradiction:
Improvemulti-axis measurement capabilityVSAvoidelectronic circuit design
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The four proof masses serve multiple functions simultaneously: they detect angular rotation about all three axes (x, y, and z) while also providing robustness against external vibrations. The symmetric arrangement enables the same physical structure to perform what would traditionally require separate one-axis gyroscopes, thereby reducing electronic circuit complexity while maintaining multi-axis measurement capability

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

5Adaptability or versatility

If all proof masses are given freedom to oscillate in many different directions, then the adaptability to measure any angular rotation is improved, but the robustness against external disturbances deteriorates

Engineering Contradiction:
Improveoscillation mode freedomVSAvoidrobustness against external disturbances
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system dynamically selects between different oscillation modes based on the measurement requirement. The proof masses are coupled to oscillate in anti-phase for primary measurement, but the same structure can be excited in cophasal mode to reject external vibrations. This dynamic adaptability allows the system to maintain robustness while measuring angular rotation about any axis by switching between appropriate oscillation modes

Inventive Principle:
Principle #15Dynamics

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 configuration enhances the robustness of multiaxis gyroscopes by minimizing the impact of external vibrations, improving the accuracy of angular rotation measurements and reducing noise from external disturbances.

Implementation Method 1

one or more sense transducers for detecting oscillation of the proof mass quartet in a z-axis, x-axis and/or y-axis secondary oscillating mode induced by the Coriolis force when the gyroscope undergoes angular rotation about the vertical, lateral, and/or transversal axes

Methodology Applied
Scientific EffectCoriolis force: Coriolis Force

Data Source

PatentEP3696504B1Multiaxis gyroscope with synchronization frame
Publication Date: 2022.03.02 MURATA MFG CO LTD
  • EP3696504B1 patent drawingFigure 1~2a
  • EP3696504B1 patent drawingFigure 2b~2c
  • EP3696504B1 patent drawingFigure 2d~2e

AI summary

This disclosure describes a microelectromechanical multiaxis gyroscope comprising a proof mass quartet, a central suspension arrangement for suspending the proof mass quartet from the central anchor point. The gyroscope also comprises a synchronization frame and a detection mass quartet. One or more lateral corner springs extends to each detection mass from the laterally adjacent proof mass, and one or more transversal corner springs extends to each detection mass from the transversally adjacent proof mass.