Vibrating Gyrometer Scale Factor Calibration via Gain Ratio
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Solution Overview
Problem
The accuracy of rotation speed measurement in axially-symmetrical vibrating rate gyros is affected by variations in the scale factor due to temperature and component aging, which existing predictive models fail to accurately account for, leading to discrepancies between stored and actual scale factor variations.
Innovation Solution
A method to calibrate the scale factor by calculating a reference gain ratio between drive gains in modal quadrature and using this ratio to determine a measurable magnitude, allowing for real-time calibration of the scale factor during use, utilizing an amplitude control signal, precession control signal, and an alternating stiffness control signal applied in specific quadratures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If predictive models are used to store scale factor variations in tables, then the gyro can operate without continuous calibration, but the measurement precision deteriorates due to inaccuracies in the predictive model
Solution Approach 1:
The gyro performs self-calibration by measuring its own scale factor variations through internal sensors and control signals. The system automatically detects changes in drive gain ratios and adjusts the scale factor without external intervention, eliminating the need for predictive models and manual calibration procedures.
Solution Approach 2:
The system continuously monitors the actual scale factor through measurements of vibration amplitude and drive gain, comparing real-time data against reference values. This feedback mechanism enables dynamic correction of scale factor deviations caused by temperature and aging effects, maintaining high measurement precision throughout the gyro's operational life.
2Duration of action of moving object
If the gyro operates over extended periods, then productivity is maintained, but measurement precision deteriorates due to component aging affecting the scale factor
Solution Approach 1:
The system performs preliminary calibration measurements at regular intervals during operation to detect and compensate for aging-induced scale factor drift. By proactively measuring and adjusting the scale factor before significant accuracy degradation occurs, the system maintains measurement precision throughout extended operational periods.
Solution Approach 2:
The gyro automatically detects and corrects scale factor variations caused by component aging through internal self-calibration routines. The system monitors its own performance degradation and applies corrective adjustments without external intervention, enabling long-term operation while maintaining measurement accuracy.
3Adaptability or versatility
If temperature variations are accounted for using stored tables, then the gyro can continue operating without calibration, but measurement precision deteriorates due to model inaccuracies
Solution Approach 1:
The system continuously monitors temperature variations and the corresponding scale factor changes through real-time measurements of drive gain and vibration characteristics. This feedback approach enables accurate compensation for temperature effects without relying on predictive models, maintaining measurement precision across varying temperature conditions.
Solution Approach 2:
The gyro performs self-calibration for temperature effects by measuring its own scale factor variations in response to temperature changes. The system automatically adjusts the scale factor based on actual measured deviations rather than relying on pre-stored temperature compensation tables, ensuring high accuracy across the operating temperature range.
4Measurement precision
If calibration is performed continuously to maintain precision, then measurement precision is maintained, but device complexity increases due to additional calibration procedures
Solution Approach 1:
The calibration system utilizes the existing multi-functional components of the gyro (control electrodes, detector electrodes, signal processing unit) to perform calibration measurements. The same hardware used for normal operation is employed for scale factor measurement and adjustment, eliminating the need for separate calibration equipment and reducing overall system complexity.
Solution Approach 2:
The gyro performs self-calibration using its own internal components and operational signals. The system measures its own scale factor variations through internal sensors and control signals, and automatically adjusts calibration parameters without requiring external calibration equipment or complex additional hardware, thereby maintaining high precision while minimizing device complexity.
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 method ensures accurate calibration of the scale factor, maintaining precision despite temperature and time variations, by leveraging the constant ratio of drive gains in modal quadrature, thereby improving measurement accuracy and reducing errors caused by aging and temperature changes.
Implementation Method 1
The vibrator member is set into vibration at the resonant frequency of the vibrator member by an amplitude control signal
Implementation Method 2
a precession control signal is also applied to the vibrator member so that a measurement of the vibration of the vibrator member and demodulation of said vibration at the resonant frequency of the vibrator member make it possible, in application of appropriate equations, to determine the speed of rotation
Data Source
AI summary
The method of calibrating a scale factor of an axially-symmetrical vibrating rate gyro operating by applying an amplitude control signal (CA) and a precession control signal (CP) to a vibrator member (1) set into vibration at a given frequency comprises a pre-calibration step consisting in calculating a reference gain ratio between a drive gain (Gmx) in a first direction and a drive gain (Gmy) in a second direction in modal quadrature with the first direction, and in storing the reference gain ratio, and a calibration step consisting in calculating a value for a measurable magnitude associated with the scale factor by a proportionality relationship including the reference gain ratio, and calculating a corrected scale factor on the basis of the value of the measurable magnitude and the stored reference gain ratio.