Vibration Gyroscope Detection Q-Factor Asymmetry
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Solution Overview
Problem
Resonant-type vibration gyroscopes face instability in measurement sensitivity due to slight differences in resonance frequencies between excitation and detection directions, leading to temperature-dependent sensitivity changes, which are exacerbated by steep Q-factor curves.
Innovation Solution
A vibration gyroscope design where the detection Q-factor is set to be smaller than the excitation Q-factor by adjusting the specific heat capacity, thermal conductivity, and linear expansion coefficient of the beams, using materials like silicon and embedding substances with lower specific heat capacity or higher thermal conductivity in the detection direction, and embedding materials with higher internal friction in the detection beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resonant-type vibration gyroscope uses high Q-factor for sensitive detection, then measurement sensitivity is improved, but measurement stability deteriorates due to steep Q-factor curves amplifying frequency differences
Solution Approach 1:
The patent changes the Q-factor parameter from high to low specifically in the detection direction to flatten the Q-factor curve. This parameter change reduces the amplification effect of resonance frequency differences, thereby stabilizing measurement sensitivity while maintaining adequate detection capability
Solution Approach 2:
The patent creates asymmetry between excitation and detection directions by setting different Q-factor values. The excitation direction maintains high Q-factor for efficient energy input, while the detection direction uses low Q-factor for stability, resolving the contradiction between sensitivity and stability
2Measurement precision
If resonance frequencies of excitation and detection directions are made identical for optimal performance, then measurement sensitivity is improved, but temperature dependence increases causing sensitivity drift
Solution Approach 1:
The patent changes the detection Q-factor parameter to a low value, which flattens the frequency response curve. This reduces the system's sensitivity to frequency shifts caused by temperature variations, thereby mitigating temperature-dependent sensitivity drift while maintaining measurement capability
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 approach stabilizes measurement sensitivity by reducing the impact of resonance frequency differences and temperature variations, resulting in a more stable angular velocity measurement.
Implementation Method 1
adjusting the specific heat capacity, thermal conductivity, and linear expansion coefficient of the beams
Implementation Method 2
adjusting the specific heat capacity, thermal conductivity, and linear expansion coefficient of the beams
Implementation Method 3
an excitation actuator vibrating the mass part in the first direction
Implementation Method 4
The resonance frequency of the mass part in the first direction and the resonance frequency in the second direction coincide with each other
Data Source
AI summary
A vibration gyroscope includes: a mass part supported to be displaceable in a first direction and a second direction; an exciter vibrating the mass part in the first direction; and a detector detecting a displacement amount of the mass part in the second direction. The first direction and the second direction are orthogonal to each other. A resonance frequency of the mass part in the first direction coincides with a resonance frequency of the mass part in the second direction. A Q-factor of vibration of the mass part in the second direction is smaller than a Q-factor of vibration of the mass part in the first direction.