Axisymmetric Vibrating Sensor Rotation Speed Determination
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Solution Overview
Problem
Axisymmetric vibrating sensors in gyroscopic mode experience significant drift errors due to harmonic components, which are influenced by the position of the vibration, temperature, and aging, limiting the accuracy of rotation speed measurement.
Innovation Solution
A method involving evaluating the speed of rotation at multiple positions of the vibration, geometrically shifted by specific angles, and averaging these evaluations to eliminate harmonic drift errors, thereby minimizing residual drift faults regardless of temperature and aging effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gyroscope operates in gyroscopic mode to measure rotation speed, then the measurement function is achieved, but drift error occurs due to harmonic components varying with vibration position
Solution Approach 1:
The invention applies periodic action by evaluating the speed of rotation at multiple positions of the vibration (N positions geometrically shifted by specific angles) and averaging these evaluations. This periodic sampling approach allows the system to capture harmonic drift errors at different phases and eliminate them through averaging, thereby resolving the drift error while maintaining continuous rotation speed measurement capability
Solution Approach 2:
The invention implements preliminary action by pre-determining the optimal positions and angular separations for vibration evaluation before actual measurement. The positions are geometrically shifted by specific angles (e.g., π/n, 2π/n, etc.) based on the harmonic order, allowing the system to eliminate specific harmonic components (n-th order and 2n-th order) through predetermined geometric configuration rather than trial-and-error adjustment
2Measurement precision
If calibration correction tables are applied to compensate drift error, then some accuracy improvement is achieved, but temperature and aging effects limit the correction effectiveness
Solution Approach 1:
The invention applies self-service by enabling the gyroscope to automatically eliminate its own drift errors through the multi-position evaluation and averaging method. The system uses its own vibration positions and measured speeds at different positions to compute and eliminate harmonic drift components, without requiring external calibration tables or manual intervention, thereby achieving temperature and aging-independent error compensation
3Stability of the object's composition
If the vibration position is fixed to eliminate drift, then measurement stability improves, but the system cannot compensate for position-dependent harmonic errors
Solution Approach 1:
The invention applies segmentation by dividing the rotation speed measurement into multiple discrete position evaluations rather than a single continuous measurement. The vibration position is evaluated at N distinct positions (e.g., 2, 3, or 4 positions) with specific angular separations, and the final speed is obtained by averaging these segmented measurements, thereby eliminating harmonic drift while maintaining effective 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 approach effectively reduces harmonic drift errors, allowing for accurate rotation speed measurement by compensating for constant and higher-order harmonic components, primarily the second and fourth order harmonics, thereby enhancing the precision of rotational speed determination.
Implementation Method 1
control electrodes and detection electrodes for generating a vibration having a deformation having a periodicity of order n and having a variable position as a function of the rotation of the sensor
Implementation Method 2
In the gyrometric mode, the vibration is maintained and its position relative to its base is kept fixed by sending an appropriate electronic command; the value of this command is then representative of the speed of rotation of the carrier in inertial space
Data Source
Figure 1~2
Figure 3~5
AI summary
The invention relates to a method for determining the rotation speed of a second-order axisymmetric vibrating sensor, that comprises the steps of: carrying out an evaluation of the rotation speed consecutively for a number N of the vibration positions relative to the electrodes, the positions being geometrically offset by a predetermined angle and the vibration being moved from one position to another by the application of a precession control using a preset scale factor; calculating an average (15) of the rotation speed estimations in the N positions, the number N of positions and the angle separating the positions being such that the average of the evaluations can be used for removing an amplitude of at least one harmonic of the vibration.