Angular Acceleration Sensor Beam Design for High S/N Ratio
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Solution Overview
Problem
Existing angular acceleration sensors face challenges in achieving both a wide detection band and a high signal-to-noise (S/N) ratio due to the trade-off between sensitivity and resonant frequency, as modifying the beam design to increase resonant frequency reduces sensitivity and vice versa, and external stress from the housing can interfere with signal detection.
Innovation Solution
The design includes a beam with a larger width than the connection portion to the fixed portion, featuring a width-direction protrusion and through-hole, with the detection element positioned to concentrate stress efficiently, and a planar portion with reduced thickness to minimize unwanted stress transmission, maintaining rotational balance and increasing sensitivity and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the beam width is increased to increase the resonant frequency, then the resonant frequency is improved, but the sensitivity is reduced and stress transmission from the fixed portion to the beam is increased
Solution Approach 1:
The beam is designed with non-uniform width along its length, with the width-direction protrusion creating a localized wider section. This allows different portions of the beam to have different properties: the protrusion section provides high resonant frequency while the narrower connection sections reduce stress transmission, thereby maintaining sensitivity.
Solution Approach 2:
The beam structure is segmented into different width sections through the width-direction protrusion. The protrusion section serves as a stress-concentrating region for detection, while the connection portions to the fixed part are narrower to minimize stress transmission from housing deflection, effectively dividing the beam into functional zones.
2Measurement precision
If through-holes are formed in the beam to reduce rigidity and increase sensitivity, then the sensitivity is improved, but the resonant frequency is reduced
Solution Approach 1:
Through-holes are formed only in the width-direction protrusion section of the beam, not throughout the entire beam. This localized approach reduces rigidity in the detection region to increase sensitivity while maintaining the overall beam stiffness required for high resonant frequency.
3Adaptability or versatility
If the beam width is increased to achieve a wide detection band, then the detection band is improved, but the stress transmission from the fixed portion to the beam is increased, reducing the S/N ratio
Solution Approach 1:
The beam has a localized width increase through the protrusion rather than a uniform width increase. This allows the detection band to be widened through the protrusion section while the narrower connection sections to the fixed part minimize stress transmission, thereby maintaining a high S/N ratio.
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 a high resonant frequency and sensitivity, achieving both a wide detection band and a high S/N ratio while minimizing interference from external stress, enhancing the precision of angular acceleration detection.
Implementation Method 1
The detection element is disposed in the beam and detects stress due to deflection of the beam along the planar surface
Implementation Method 2
The weight is elastically supported on the fixed portion by the beam
Data Source
AI summary
An angular acceleration sensor includes a planar surface extending along an X-Y plane, a fixed portion, a weight, a beam, and piezoresistors. The weight is supported by the fixed portion. The beam extends along a Y-axis and is connected to the fixed portion and the weight. A width of the beam in an X-axis direction is larger than a width of the connection portion at which the beam is connected to the fixed portion.