Angular Velocity Sensor with Segmented Mass Bodies
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Solution Overview
Problem
Angular velocity sensors face interference between driving and sensing modes due to manufacturing errors, leading to reduced sensitivity and increased air damping, limiting the accuracy of angular velocity measurement.
Innovation Solution
The angular velocity sensor design includes multiple frames and flexible parts that restrict movement to specific directions, minimizing interference and maximizing driving displacement, thereby enhancing sensing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mass body is adhered to an elastic substrate to measure angular velocity, then the angular velocity can be calculated by measuring Coriolis force, but interference between driving mode and sensing mode occurs due to manufacturing errors, deteriorating sensitivity
Solution Approach 1:
The sensor is divided into separate driving and sensing units with distinct mass bodies (first and second mass bodies) that operate independently. The driving unit generates driving displacement while the sensing unit detects Coriolis force, preventing interference between modes even with manufacturing variations
Solution Approach 2:
The first and second mass bodies are positioned asymmetrically at opposite sides of the elastic substrate, with the first mass body for driving and the second for sensing. This asymmetric configuration ensures that manufacturing errors do not cause coupling between driving and sensing modes
2Measurement precision
If driving and sensing modes are made to coincide in resonant frequency, then measurement sensitivity should improve, but very large interference occurs between driving mode and sensing mode due to manufacturing errors
Solution Approach 1:
The sensor separates driving and sensing functions into distinct units with different mass bodies. The driving unit and sensing unit have different resonant frequencies, eliminating interference while maintaining high sensitivity through dedicated optimization of each unit
Solution Approach 2:
The sensing function is extracted from the driving mass body and placed in a separate second mass body. This extraction allows the sensing mode to operate independently without interference from driving mode vibrations, even when resonant frequencies are close
3Measurement precision
If circuit amplification is increased to improve sensitivity, then angular velocity signal detection improves, but noise signal is significantly larger than angular velocity signal
Solution Approach 1:
By separating driving and sensing into distinct units, the Coriolis force signal is generated cleanly without contamination from driving mode noise. This allows for lower amplification levels that maintain signal integrity while minimizing noise amplification
4Length of moving object
If air damping is reduced to maximize driving displacement, then sensing efficiency improves, but structural characteristics inevitably generate air damping
Solution Approach 1:
The separation of driving and sensing mass bodies allows each to be optimized independently for minimal air damping. The driving mass body can achieve larger displacement while the sensing mass body remains compact, both operating with reduced air damping effects
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 design improves the sensitivity and accuracy of angular velocity measurement by reducing the effects of manufacturing errors and air damping, allowing for more effective displacement and detection of angular velocity.
Implementation Method 1
the angular velocity sensor may calculate the angular velocity by measuring Coriolis force applied to the mass body
Implementation Method 2
a first flexible part respectively connecting the first and second mass bodies to the first frame; a second flexible part respectively connecting the first and second mass bodies to the first frame
Data Source
AI summary
Disclosed herein is an angular velocity sensor including: first and second mass bodies; a first frame provided at an outer side of the first and second mass bodies; a first flexible part connecting the first and second mass bodies to the first frame in a Y axis direction, respectively; a second flexible part connecting the first and second mass bodies to the first frame in an X axis direction, respectively; a second frame provided at an outer side of the first frame; a third flexible part connecting the first and second frames to each other in the X axis direction; and a fourth flexible part connecting the first and second frames to each other in the Y axis direction, wherein the first frame has a thickness in a Z axis direction thinner than that of the second frame.