Viscous Damped Linear Accelerometer for Vibration Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MEMS and NEMS accelerometers face degradation or damage in severe vibratory environments, with existing solutions either ineffective in filtering low-frequency vibrations or compromising mechanical structure integrity.
Innovation Solution
A linear accelerometer design featuring a rotationally movable part with a distinct center of gravity, combined with viscous damping means spread between the moving and fixed parts, providing significant damping while maintaining resolution and reducing high-frequency sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a mechanical decoupling frame with low stiffness is used to filter vibrations, then vibrations above 1 kHz are filtered, but vibrations below 1 kHz are not filtered and are thus detected
Solution Approach 1:
The patent changes the damping parameter by introducing viscous damping means that provide frequency-dependent damping. The damping coefficient is designed to be significant at low frequencies (below 1 kHz) while maintaining appropriate behavior at higher frequencies, thereby filtering low-frequency vibrations that conventional low-stiffness structures cannot filter.
2Object-affected harmful factors
If electronic filtering is used to remove undesirable vibrations, then vibrations at certain frequencies can be filtered, but the mechanical structure is not protected and filtering is ineffective when vibration frequency matches the frequency of interest
Solution Approach 1:
The patent introduces viscous damping means as an intermediary element between the moving mass and the fixed support. This intermediary provides mechanical damping that directly protects the structure from vibratory stresses while simultaneously filtering unwanted vibrations, unlike electronic filtering which only processes signals after detection.
3Object-affected harmful factors
If the resonance frequency is reduced to reduce sensitivity at higher frequencies, then the accelerometer becomes less sensitive to high-frequency vibrations, but the pass band is widened and resolution is degraded
Solution Approach 1:
The patent applies local quality by implementing viscous damping means at specific locations (interdigitated combs between moving and fixed parts) rather than uniformly across the entire structure. This localized damping provides frequency-selective attenuation that reduces high-frequency sensitivity while preserving the pass-band characteristics and resolution through careful design of the damping zones.
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 design achieves considerable damping with reduced sensitivity to high frequencies, allowing for a compact accelerometer with preserved resolution and improved protection against vibratory damage.
Implementation Method 1
means capable of generating viscous damping of the moving part, the means capable of generating viscous damping being spread out between the moving part and the fixed part
Data Source
AI summary
Linear accelerometer comprising a fixed part, a rotationally moving part in the plane of the accelerometer around an axis of rotation orthogonal to the plane of the accelerometer, the moving part comprising a centre of gravity distinct from the point of intersection of the axis of rotation and the plane of the accelerometer, means forming pivot link between the moving part and the fixed part, means for detecting the displacement of the moving part with respect to the fixed part, means for viscous damping the displacement of the moving part in said plane, said viscous damping means comprising interdigitated combs, at least one first comb on the moving part and at least one second comb on the fixed part (2), the first comb and the second comb being interdigitated.