Compound Sensor Angular Rate Detection Centrifugal Force Separation

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Solution Overview

Problem

Conventional angular rate sensors face challenges in accurately detecting angular rates due to centrifugal forces and vibration issues, especially when mounted on elastic members that can deform, leading to inaccurate readings.

Innovation Solution

A compound sensor design with four oscillators symmetrically arranged to detect angular rate, acceleration, and centrifugal force, where each oscillator is driven in a transverse direction and displaced in a longitudinal direction, allowing for the separation and accurate detection of these physical components by calculating resultant forces using specific formulas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If four oscillators are symmetrically arranged and driven in opposite phase to detect angular rate, then the sensor can detect angular rate through Coriolis force, but centrifugal force acts in the detecting axial direction causing measurement error

Engineering Contradiction:
Improveangular rate detection accuracyVSAvoidcentrifugal force interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent segments the detection function into multiple oscillators (first and second oscillators) with different driving directions. The first oscillator detects along the first axis while the second oscillator detects along the second axis perpendicular to the first. This segmentation allows separate measurement of Coriolis force components and centrifugal force, enabling the centrifugal force to be cancelled out through differential processing while maintaining accurate angular rate detection.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If the angular rate sensor is mounted on an elastic member such as a dumper to remove vibration, then vibration isolation is achieved, but deformation of the elastic member causes the sensor to vibrate and rotate

Engineering Contradiction:
Improvevibration isolationVSAvoiddetection accuracy under mounting conditions
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent makes the sensor system universal by enabling it to detect multiple physical quantities simultaneously - angular rate, acceleration, and centrifugal force. The same oscillator structure and detection mechanism are used for all three types of detection, allowing the sensor to function accurately regardless of mounting conditions or vibration levels, thereby improving reliability in real-world applications.

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

3Measurement precision

If oscillators are driven in transverse direction and displaced in longitudinal direction to separate detection components, then accurate separation of angular rate, acceleration and centrifugal force is achieved, but device complexity increases

Engineering Contradiction:
Improvecomponent separation accuracyVSAvoidoscillator configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces dimensional separation by driving oscillators in transverse directions (first axis and second axis perpendicular to each other) while detecting displacements in the longitudinal direction. This dimensional approach allows the same detection structure to measure multiple components (angular rate, acceleration, centrifugal force) by exploiting the geometric relationships between different spatial dimensions, achieving component separation without proportionally increasing structural complexity.

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

Enables high-accuracy detection of angular rate, acceleration, and centrifugal force components, improving robustness against production dispersion and vibration-induced errors.

Implementation Method 1

all adjacent oscillators are driven and oscillated in opposite phase of a circumferential direction centered around the predetermined point, and if an angular rate occurs around an axis perpendicular to the substrate, detecting masses of respective oscillators are displaced in a direction perpendicular to a driving oscillation. A Coriolis signal is taken out by calculating and processing capacitance change

Methodology Applied
Scientific EffectCoriolis force: Coriolis Force

Implementation Method 2

A Coriolis signal is taken out by calculating and processing capacitance change between the detecting masses and the oscillators

Methodology Applied
Scientific EffectCapacitance change: Capacitance

Implementation Method 3

a first oscillator and a second oscillator which are different from each other are driven in a transverse direction and are displaced in a longitudinal direction

Methodology Applied
Scientific EffectInertial force: Inertia

Data Source

PatentEP2584312B1Composite sensor
Publication Date: 2020.02.05 TOYOTA JIDOSHA KK
  • EP2584312B1 patent drawingFigure 1
  • EP2584312B1 patent drawingFigure 2
  • EP2584312B1 patent drawingFigure 3A

AI summary

A compound sensor includes a first unit including first and second oscillators symmetrically disposed to each other and being able to be displaced in a driving direction and a detecting direction; a second unit including third and fourth oscillators symmetrically disposed to each other and being able to be displaced in the driving direction and the detecting direction; a drive unit configured to drive the first, second, third and fourth oscillators so as to oscillate the first and second oscillators in opposite phase to each other, and the third and fourth oscillators in opposite phase to each other, and so as to oscillate the first unit and the second unit in opposite phase to each other; and a detection unit configured to detect displacements of the first, second, third and fourth oscillators in the detecting direction.