Vibrating Gyroscope Calibration via Sinusoidal Disturbance Injection

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Solution Overview

Problem

Vibrating gyroscopes used in gyrometer mode cannot be calibrated for bias defects and scale factor corrections due to fixed vibration position, which limits their accuracy and adaptability to changing conditions like temperature.

Innovation Solution

A method involving a sinusoidal disturbance injection into the servo loop of the gyroscope's control system to calibrate operational parameters without rotating the vibration position, allowing for correction of errors and adaptation to environmental changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a vibrating gyroscope is used in gyrometer mode with fixed vibration position, then the device can maintain stable operation, but calibration for bias defects and scale factor corrections cannot be performed

Engineering Contradiction:
Improvestable operationVSAvoidcalibration accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by temporarily modifying the operational mode of the gyroscope during calibration. The vibration position, which is normally fixed in gyrometer mode, is dynamically adjusted by rotating it to different positions (0°, 90°, 180°, 270°) to enable calibration measurements. This dynamic change allows the system to switch between stable operation and calibration capability as needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The calibration process employs periodic action by repeatedly rotating the vibration position through a sequence of four distinct orientations (0°, 90°, 180°, 270°) and performing measurements at each position. This periodic rotation and measurement cycle is executed multiple times to gather sufficient data for accurate calibration of bias and scale factor while maintaining the overall stable operation of the device.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If internal calibration is performed by rotating vibration position, then correction coefficients can be determined, but this cannot be applied to gyroscopes used in gyrometer mode with fixed vibration position

Engineering Contradiction:
Improvecorrection coefficient accuracyVSAvoidmode compatibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent achieves universality by creating a calibration method that works across different operational modes. The proposed technique allows gyroscopes in gyrometer mode (with fixed vibration position) to undergo calibration, just like gyroscopes in gyroscope mode. The calibration coefficients determined through this method are universally applicable to improve measurement accuracy regardless of the operational mode, making the calibration process adaptable to various usage scenarios.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If the vibration position is rotated for calibration, then bias defects and scale factor can be corrected, but the operational constraint of not rotating vibration position in gyrometer mode is violated

Engineering Contradiction:
Improveerror correctionVSAvoidoperational constraint compliance
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent applies segmentation by separating the calibration operation from the normal measurement operation. The calibration process is segmented into distinct phases where vibration position rotation is temporarily permitted, followed by application of correction coefficients. Once calibration is complete, the system returns to normal gyrometer operation with fixed vibration position. This segmentation allows error correction to be performed without compromising the operational constraints during normal usage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The calibration process is performed as a preliminary action before normal operational use. By completing the vibration position rotation and correction coefficient determination in advance, the system ensures that subsequent measurements benefit from the calibration without requiring continuous rotation. The preliminary calibration action establishes accurate correction coefficients that remain valid during fixed-position operation, satisfying operational constraints while achieving error correction.

Inventive Principle:
Principle #10Preliminary action

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

Enables accurate calibration and error correction of vibrating gyroscopes in gyrometer mode, improving their operational stability and accuracy over time and under varying conditions.

Implementation Method 1

obtaining a modified command to be applied to the gyrometer for said operational parameter by introducing a sinusoidal disturbance into the current command

Methodology Applied
Scientific EffectSinusoidal disturbance: Driven Harmonic Oscillation

Implementation Method 2

vibrating gyroscopes whose principle is based on the Coriolis effect

Methodology Applied
Scientific EffectCoriolis effect: Coriolis Force

Data Source

PatentEP2573515B1Vibrating gyroscope calibration
Publication Date: 2019.11.06 SAFRAN ELECTRONICS & DEFENSE (FR)
  • EP2573515B1 patent drawingFigure 1~4
  • EP2573515B1 patent drawingFigure 3
  • EP2573515B1 patent drawing

AI summary

The method involves obtaining a modified command to be applied to an operational parameter e.g. amplitude, of a gyroscope by introducing a sinusoidal disruption in a current command of the gyroscope (11), and applying the modified command as the current command to the gyroscope (12). A measurement value resulting from the application of the modified command is determined (13), and a correction value of the operational parameter is identified (15) based on a correlation (14) between the measured value and the modified command. The value is applied to measurements provided by the gyroscope. An independent claim is also included for a gyroscopic system.