Resonant Sensor Tensile Strain and Orthogonal Vibration
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Solution Overview
Problem
Resonant sensors face challenges in expanding their dynamic range for measuring negative input accelerations without compromising measurement accuracy, as they tend to buckle under compression strain, limiting their ability to accurately detect both positive and negative acceleration inputs.
Innovation Solution
The resonant sensor design incorporates a silicon substrate with a weight, spring, and acceleration detecting resonator, where the resonator is embedded with tensile strain and vibrates perpendicular to the spring's direction, preventing energy absorption and enhancing sensitivity to both positive and negative accelerations by adjusting the gap and pressure between the weight and damping member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the spring stiffness is reduced or weight is increased to expand dynamic range, then the strain added to the resonator becomes larger, but the resonator is easily buckled under compression strain
Solution Approach 1:
The resonator is preliminarily subjected to tensile strain to create a state of tension that counteracts the compressive strain generated during negative acceleration measurement. This preliminary anti-action prevents buckling by ensuring the resonator remains in a tensile state throughout the measurement range, allowing dynamic range expansion without compromising reliability.
Solution Approach 2:
The invention changes the strain state parameter of the resonator from a neutral or compressive state to a tensile state. By applying preliminary tensile strain and configuring the system so the resonator operates in tension during both positive and negative acceleration inputs, the fundamental parameter that governs buckling resistance is altered, enabling wider dynamic range.
2Device complexity
If the resonator vibrates in the same direction as the spring bending, then the spring structure is simple, but the spring absorbs energy from the resonator reducing measurement accuracy
Solution Approach 1:
The resonator is configured to vibrate in a direction perpendicular to the spring's bending direction. This dimensional change in vibration orientation prevents energy coupling between the spring and resonator, eliminating the energy absorption problem while maintaining structural simplicity. The orthogonal arrangement ensures independent operation of the spring support mechanism and resonator sensing function.
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 significantly expands the dynamic range of the sensor, allowing for accurate measurement of both positive and negative accelerations without buckling, thereby improving measurement accuracy and stability.
Implementation Method 1
detecting a change of resonant frequency of the resonator caused by strain of the spring... by vibrating the resonator by using an exciting circuit and detecting the resonant frequency
Implementation Method 2
A damping characteristic of a frequency characteristic of the resonant sensor is changed in accordance with a size of a gap formed between the weight and the damping member and pressure in the gap. The gap acts as a damper with respect to the weight.
Data Source
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AI summary
A resonant sensor includes a mover that is movable in a first direction, a supporter that extends in a second direction perpendicular to the first direction, the supporter being connected to the mover and a fixer, the supporter supporting the mover which is movable in the first direction, and a resonator that is vibratable, at least a part of the resonator being embedded in the supporter.