Coriolis Gyroscope Quadrature Bias Correction via Electrostatic Units
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Solution Overview
Problem
Coriolis gyroscopes face significant challenges in reducing quadrature bias due to manufacturing tolerances, which lead to misalignment and phase-shifted signal errors, making it difficult to accurately measure rotation rates without rotating or deflecting the Coriolis mass and requiring buried oxides in the manufacturing process.
Innovation Solution
The implementation of a Coriolis gyroscope system with first and second correction units, each comprising stationary and moving correction electrodes, where the stationary electrodes are anchored to the substrate and the moving electrodes are part of the mass system, allowing for the application of constant corrective voltages to reduce quadrature bias without relying on buried oxides or mass deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction electrodes are used to reduce quadrature bias, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The correction electrodes are integrated into the existing mass system structure, where parts of the mass system itself serve as moving correction electrodes. This merging approach reduces the need for separate correction components while achieving quadrature bias compensation through the interaction between stationary and moving electrodes.
Solution Approach 2:
The mass system components serve dual functions: they act as both the primary inertial mass for rotation sensing and as moving correction electrodes for quadrature bias reduction. This multi-functionality eliminates the need for dedicated correction structures, thereby reducing device complexity while maintaining measurement precision.
2Measurement precision
If traditional correction methods with individual electrodes are used, then quadrature bias is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The correction unit employs an asymmetric arrangement where the moving correction electrodes are integral parts of the mass system with inherent mechanical connections. This asymmetric design anchored to the substrate eliminates the need for precise symmetrical spacing between individual correction electrodes, thereby reducing manufacturing precision requirements while maintaining effective quadrature bias compensation.
3Measurement precision
If buried oxides are used in the manufacturing process, then correction electrode implementation is enabled, but ease of manufacture decreases
Solution Approach 1:
The invention extracts the correction electrode function from the substrate and implements it through moving electrodes that are integral parts of the mass system. This extraction eliminates the requirement for buried oxide layers in the manufacturing process, thereby simplifying fabrication while maintaining the ability to reduce quadrature bias through the correction unit.
4Measurement precision
If the Coriolis mass is rotated and deflected for correction, then quadrature bias is reduced, but loss of energy increases
Solution Approach 1:
The invention replaces the mechanical approach of rotating and deflecting the Coriolis mass with an electrostatic field-based correction mechanism. Stationary correction electrodes generate electrostatic forces that act on the moving correction electrodes (parts of the mass system) to compensate for quadrature bias without requiring physical rotation or large deflections of the mass, thereby reducing energy loss.
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 solution effectively minimizes quadrature bias by applying corrective voltages to the correction units, ensuring accurate rotation rate measurement independent of mass deflection and manufacturing tolerances, while simplifying the manufacturing process by avoiding the need for buried oxides.
Implementation Method 1
forces resulting from electrostatic interactions between stationary and moving correction electrodes
Implementation Method 2
a deflection of the mass along a second, perpendicular axis due to a Coriolis force, is detectable
Data Source
AI summary
A Coriolis gyroscope comprises a mass system that can be excited to perform vibrations parallel to a first axis, whereby a deflection of the mass system due to a Coriolis force along a second axis perpendicular to the first axis is detectable. At least one first correction unit and at least one second correction unit, which each comprise a plurality of stationary correction electrodes and moving correction electrodes whereby the stationary correction electrodes extend in the direction of the first axis and are firmly connected to the substrate by corresponding anchor structures, and the moving correction electrodes are provided as a part of the mass system. A method for reducing the quadrature bias of a Coriolis gyroscope of this type comprises applying at least temporarily constant corrective voltages to the correction units.