Piezoelectric Angular Velocity Sensor Suppressing Leak Vibration
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Solution Overview
Problem
Conventional vibration-type angular velocity sensors suffer from 'leak vibration' due to dimensional and alignment errors, leading to reduced accuracy in angular velocity detection.
Innovation Solution
The sensor design includes a substrate with a drive beam, a drive weight, a detection weight, and a detection beam that displaces in a direction intersecting the vibration direction, utilizing piezoelectric films to generate an electric output based on the detection weight's movement, thereby suppressing unintended deformation and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional vibration-type angular velocity sensors are used, then the basic function of detecting angular velocity is achieved, but dimensional and alignment errors cause leak vibration that reduces detection accuracy
Solution Approach 1:
The sensor structure is segmented into distinct functional components: drive beams for generating vibration, detection beams for measuring Coriolis force, drive weights and detection weights with specific mass distributions, and piezoelectric films for actuation and sensing. This segmentation allows each component to be optimized independently, reducing the impact of manufacturing errors on overall performance
Solution Approach 2:
Piezoelectric films are selectively applied to specific regions of the beams and weights where stress and strain are maximized during operation. The drive piezoelectric films are positioned on drive beams to generate controlled vibration, while detection piezoelectric films are placed on detection beams to sense Coriolis-induced displacement. This localized application ensures that the most critical measurement zones have the highest quality materials and structures
2Measurement precision
If the detection beam is designed to displace in a direction intersecting the vibration direction, then sensitivity to angular velocity is improved, but the structure becomes more complex
Solution Approach 1:
The detection beam is intentionally designed with asymmetric orientation relative to the drive beam, displacing in a direction that intersects rather than parallels the drive vibration direction. This asymmetric configuration maximizes the detection of Coriolis force while the overall structure maintains symmetry through paired beams and weights to cancel common-mode errors
Solution Approach 2:
Multiple functions are merged into integrated components: the detection beam serves both as a structural support element and as the sensing element that directly measures Coriolis displacement. The piezoelectric films serve dual purposes of actuation (drive) and sensing (detection) within the same device structure, reducing the need for separate mechanical components
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 accuracy of angular velocity detection by minimizing leak vibration and maintaining sensitivity within a target frequency band.
Implementation Method 1
a detection part in the detection beam generating an electric output corresponding to a displacement of the detection beam when an angular velocity is applied
Data Source
AI summary
An angular velocity sensor includes: a substrate; a drive beam supported via a support member with a fixing part; a drive weight supported with the drive beam; a detection weight supported via a beam part including a detection beam with the drive weight; and a detection part in the detection beam generating an electric output corresponding to a displacement of the detection beam when an angular velocity is applied. When the angular velocity is applied while the drive weight and the detection weight vibrate and are driven by the drive beam, the detection beam is displaced in a direction intersecting the vibration direction. The angular velocity is detected based on a change of an output voltage of a detection piezoelectric film in accordance with a displacement of the detection beam.