Vibration Gyro Offset Switching for Temperature-Stable Bias
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Solution Overview
Problem
Existing vibration-type angular velocity sensors face issues with temperature-induced fluctuations in bias components due to asymmetrical offset values before and after switching between electrodes, leading to unsymmetrical control and increased temperature fluctuations.
Innovation Solution
The sensor is designed with interchangeable primary and secondary side control circuits, ensuring symmetrical offset values before and after interchange, and incorporates offset values to correct sensor outputs based on temperature changes, reducing errors due to crosstalk and gain fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offset values are adjusted individually before and after switching to cancel bias components, then bias cancellation is improved, but temperature fluctuation of remaining bias increases due to asymmetry
Solution Approach 1:
The patent applies asymmetry principle by intentionally introducing asymmetrical offset values before and after switching. Specifically, a first offset value is added before switching and a second offset value (with different magnitude or sign) is added after switching. This controlled asymmetry compensates for the inherent asymmetry in the sensor structure, thereby reducing the temperature fluctuation of the remaining bias component while maintaining effective bias cancellation.
Solution Approach 2:
The patent changes the offset parameters before and after switching based on temperature characteristics. By adjusting the first and second offset values according to temperature-dependent bias behavior, the system optimizes bias cancellation at different temperatures and reduces the temperature fluctuation of remaining bias.
2Measurement precision
If switching between electrodes is performed to cancel bias components, then zero-point accuracy is improved, but temperature-induced fluctuations in remaining bias occur
Solution Approach 1:
The patent employs feedback mechanisms by monitoring the bias component and dynamically adjusting the first and second offset values based on temperature measurements or bias detection results. This feedback loop ensures that the offset correction adapts to temperature changes, maintaining zero-point accuracy while minimizing temperature-induced fluctuations in remaining bias.
Solution Approach 2:
The patent applies preliminary action by pre-calculating or pre-setting the first and second offset values based on expected temperature ranges or calibration data. These offset values are prepared in advance to compensate for anticipated temperature variations, thereby reducing temperature-induced fluctuations before they affect the measurement.
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 suppresses temperature-induced bias fluctuations, enhancing the accuracy and symmetry of the sensor output by making offset values symmetrical and correcting errors related to gain changes.
Implementation Method 1
a vibration-type angular velocity sensor is known from EP 3 112 804 A1. Moreover, a vibration-type angular velocity sensor is disclosed in, for example, Japanese Unexamined Patent Publication No. 2009-115559 and Japanese Patent No. 6463335
Data Source
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AI summary
A vibration-type angular velocity sensor (100) includes a primary side control circuit (2) and a secondary side control circuit (3) which are configured so that a function as the primary side control circuit (2) and a function as the secondary side control circuit (3) are interchangeable, in which an offset value after interchange and an offset value before interchange are symmetric values with respect to a predetermined reference value.