Micromechanical Three-Axis Gyroscope with Shared Drive

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Solution Overview

Problem

Current micromechanical yaw rate sensors for automotive applications, especially in complex systems like automated driving and two-wheeler navigation, require robust three-axis sensors but often suffer from interference modes due to external forces and non-linear crosstalk, which can lead to incorrect signal readings.

Innovation Solution

A micromechanical yaw rate sensor arrangement that combines a single-axis and a two-axis rotation rate sensor via a common drive mechanism, eliminating the need for separate drive structures and frequencies, thereby reducing interference modes and ensuring robustness against external linear and rotary acceleration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If three individual single-axis gyroscopes are used to form a three-axis sensor, then the sensor can measure rotation rates about three axes, but the number of interference modes triples due to each gyroscope having the same interference modes at different frequencies

Engineering Contradiction:
Improvethree-axis measurement capabilityVSAvoidinterference modes
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent combines a first single-axis gyroscope and a second dual-axis gyroscope into a single integrated three-axis sensor assembly, sharing common structural elements and drive mechanisms. This merging reduces the total number of independent interference modes compared to using three separate single-axis gyroscopes, as the shared structures create correlated response characteristics rather than tripled independent interference patterns.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The second gyroscope in the assembly is designed with dual-axis capability, allowing it to contribute to measurements on two different axes simultaneously. This multi-functionality reduces the overall component count and interference mode proliferation compared to using three single-axis devices, while still achieving complete three-axis coverage when combined with the first gyroscope.

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

2Ease of manufacture

If three identical single-axis gyroscopes are used, then the manufacturing process is simplified, but all gyroscopes have the same interference modes which lie at different frequencies, tripling the total number of interference modes

Engineering Contradiction:
Improveidentical component fabricationVSAvoidtotal interference modes
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges two gyroscope devices into a single integrated assembly where they share common structural support, drive mechanisms, and signal processing pathways. This combining approach reduces the overall device complexity and interference mode count despite using identical or similar gyroscope components, as the shared architecture creates coupled dynamics rather than independent interference patterns.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If separate drive structures are used for each gyroscope, then each gyroscope can be independently controlled, but the wiring and drive structures must be eliminated to achieve a compact design

Engineering Contradiction:
Improveindependent control capabilityVSAvoiddrive structures and wiring
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines the drive mechanisms of two gyroscopes into a shared drive structure that can excite both devices simultaneously or independently through common actuators. This merging eliminates redundant wiring and drive electronics while maintaining the ability to independently control each gyroscope's oscillation, achieving compact integration without sacrificing operational independence.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common drive structure is designed with multi-functionality to serve both gyroscopes simultaneously, capable of generating independent oscillation signals for each device through shared actuation mechanisms. This universal drive approach reduces the overall wiring harness and electronic control complexity compared to having separate dedicated drive systems for each gyroscope.

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

4Ease of operation

If different drive frequencies are used for various gyroscopes, then each can operate independently, but mutual interference occurs through parasitic crosstalk of drive forces

Engineering Contradiction:
Improveindependent operationVSAvoidparasitic crosstalk
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent employs periodic oscillation at carefully selected resonant frequencies for each gyroscope, where the drive frequencies are chosen to be harmonically related or sufficiently separated to minimize parasitic crosstalk. This periodic actuation at optimized frequencies allows independent operation while reducing mutual interference through frequency domain separation rather than temporal multiplexing.

Inventive Principle:
Principle #19Periodic action

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 solution provides a compact, robust three-axis yaw rate sensor that minimizes interference modes, avoids misalignments, and simplifies packaging, ensuring accurate signal detection by using a single drive control loop and capacitive detection structures sensitive to multiple axes.

Implementation Method 1

a first rotor device (1a), which can be driven to oscillate about a first axis (z-axis), and a second rotor device (1b), which can be driven to oscillate about the first axis (z-axis) in opposite phase to the first rotor device (1a)... The first rotor device (1a) can be tilted about a second axis (y-axis) by a first external rotation rate and about a third axis (x-axis) by a second external rotation rate

Methodology Applied
Scientific EffectCoriolis effect: Coriolis Force

Implementation Method 2

a first frame (R1), and a second frame (R2)... wherein the first frame (R1) can be driven to oscillate along the second axis (y-axis), and wherein the second frame (R2) can be driven to oscillate along the second axis (y-axis) in opposite phase to the first frame (R1), and wherein the first frame (R1) and the second frame (R2) can be deflected in opposite phase to the first axis (z-axis) by a third external rotation rate

Methodology Applied
Scientific EffectCoriolis effect: Coriolis Force

Implementation Method 3

The first coupling device (S1, S2) comprises a first spring device (F12) by which the first rotor device (1a) and the second rotor device (1b) are coupled such that parallel tilting about the second axis (y-axis) is suppressed and antiparallel tilting about the second axis (y-axis) is enabled

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3679323B1Three axis micromechanical rotational rate sensor arrangement with linearly and rotationally drivable sensor devices
Publication Date: 2022.06.01 ROBERT BOSCH GMBH
  • EP3679323B1 patent drawingFigure 1
  • EP3679323B1 patent drawingFigure 2
  • EP3679323B1 patent drawingFigure 3a~5c

AI summary

The invention relates to a micromechanical rotation rate sensor arrangement and a corresponding production method. The micromechanical rotation rate sensor arrangement according to the invention comprises a first rotation rate sensor device (100), which is rotatably drivable in an oscillating manner about a first axis (z), in order to detect a first outer rotation rate about a second axis (y) and a second outer rotation rate about a third axis (x), wherein the first, second and third axis (z, y, x) are arranged perpendicular to each other, and a second rotation rate sensor device (200; 201; 202), which is drivable in a linear oscillating manner along the second axis (y) by a drive device (AT; AT'; AT"), in order to detect a third outer rotation rate about the first axis (z). The second rotation rate sensor device (200; 201; 202) is connected to the first rotation sensor device (100) in order to drive the first rotation rate sensor device (100) by means of the drive device (200; 201; 202) via a first coupling device (S1, F5; S2, F6; SA, SB, F12).