Three-Axis Gyroscope Lever Spring Coupling for Perpendicular Drive

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Solution Overview

Problem

Existing three-axis gyroscopes face challenges in achieving mutually perpendicular detection axes, leading to suboptimal signal processing and sensitivity due to reaction forces from coupling devices, which deviate from the optimal direction of driving motion.

Innovation Solution

The integration of two and one-axis gyroscopes with a push and pull type coupling spring lever arrangement, where a symmetrical lever spring system couples linear drive mode oscillations between the gyroscopes, ensuring equal amplitudes and perpendicularity, thus achieving equal sensitivity and independent detection signals across axes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a coupling device is used to synchronize drive elements in a three-axis gyroscope, then the drive movements can be synchronized, but reaction forces from the coupling device introduce components that deviate from the optimal mutually perpendicular direction of driving motion

Engineering Contradiction:
Improvesynchronization of drive movementsVSAvoidperpendicularity of detection axes
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The gyroscope is divided into three separate drive elements (first, second, and third drive elements) that can be independently controlled. Each drive element operates along a mutually perpendicular axis, allowing independent optimization of each axis while maintaining overall system synchronization through separate actuation signals.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A coupling spring is introduced as an intermediary element that mechanically connects the three drive elements. This spring-based coupling transmits synchronization forces while being compliant enough to accommodate the perpendicular orientation requirements of each axis, thereby mediating between the need for synchronization and the need for precise perpendicularity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If three drive elements are connected for synchronizing driving movements, then synchronization is achieved, but reaction forces deviate from the optimal direction of driving motion

Engineering Contradiction:
Improvesynchronization efficiencyVSAvoiddetection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

Each drive element is designed with localized drive regions that are optimized for their specific axis of motion. The coupling spring is positioned and oriented to apply forces locally at specific points on each drive element, ensuring that reaction forces are minimized and do not interfere with the primary detection measurements on any given axis.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If detection motions are made mutually perpendicular for simplified signal processing, then signal independence is improved, but achieving equal sensitivity across all axes becomes more difficult

Engineering Contradiction:
Improvesignal processing simplicityVSAvoidequal sensitivity across axes
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The coupling spring is designed with asymmetric geometry relative to the individual drive elements, with different attachment points and orientations for each axis. This asymmetric design compensates for variations in mechanical coupling strength across the three perpendicular axes, allowing each axis to achieve equal sensitivity despite the inherent asymmetries in a three-dimensional perpendicular arrangement.

Inventive Principle:
Principle #4Asymmetry

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 allows for accurate detection of angular velocity in any direction with mutually perpendicular detection axes, simplifying signal processing and ensuring equal sensitivity across all axes, thereby improving the performance of the three-axis gyroscope.

Implementation Method 1

a lever spring system used to couple a first linear drive mode oscillation of a first gyroscope into a second linear drive mode oscillation of a second gyroscope

Methodology Applied
Scientific EffectMechanical coupling: Mechanical Force

Implementation Method 2

push and pull type coupling spring lever arrangement

Methodology Applied
Scientific EffectSpring mechanism: Spring

Implementation Method 3

coupling spring lever arrangement

Methodology Applied
Scientific EffectLever mechanism: Lever

Implementation Method 4

When a mass is moving in one direction called primary motion and rotational angular velocity is applied, the mass experiences a force in orthogonal direction as a result of the Coriolis force

Methodology Applied
Scientific EffectCoriolis force: Coriolis Force

Implementation Method 5

Resulting physical displacement caused by the Coriolis force may be then read from, for example, a capacitive, piezoelectrical or piezoresistive sensing structure

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Data Source

PatentEP3283845B1Three axis gyroscope
Publication Date: 2019.06.26 MURATA MFG CO LTD
  • EP3283845B1 patent drawingFigure 1
  • EP3283845B1 patent drawingFigure 2
  • EP3283845B1 patent drawingFigure 3

AI summary

A micro-electro-mechanical device detects angular velocity, for example relating to a three axis gyroscope. The three axis gyroscope includes a two axis gyroscope structure and a one axis gyroscope structure. The gyroscope further includes a lever spring system coupling a linear drive mode oscillation of the two axis gyroscope structure and a linear drive mode oscillation of the one axis gyroscope structure into one combined primary motion. The lever spring system causes the one and two axis gyroscope structures to have equal drive mode oscillation amplitudes. A symmetrical arrangement of the lever spring system causes any reactive forces created in the lever spring system to cancel each other.