Annular Resonator Gyroscope With Dynamic Fine Frequency Tuning

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Solution Overview

Problem

Existing vibrating structure gyroscopes face performance limitations due to residual frequency splits between high and low frequency modes caused by geometrical imperfections in the annular resonator, which are not adequately addressed by current electrostatic balancing methods, especially under dynamic conditions.

Innovation Solution

The implementation of a vibrating structure gyroscope with a set of digitally-controlled capacitive balancing electrodes that apply a static frequency offset to both the high and low frequency modes, followed by a dynamic fine balancing voltage to maintain frequency balance, improving resolution and counteracting operational imbalances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If static electrostatic balancing voltages are applied to reduce frequency split, then frequency matching between modes is improved, but resolution of dynamic frequency adjustment is degraded

Engineering Contradiction:
Improvefrequency matchingVSAvoiddynamic frequency adjustment resolution
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The balancing electrode plates are divided into two distinct sets: a first set for applying static balancing voltages to reduce the main frequency split, and a second set for applying dynamic fine balancing voltages to maintain frequency matching during operation. This segmentation allows each set to be optimized for its specific function without interfering with the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from purely static balancing to a dynamic balancing approach where the second set of electrode plates can apply time-varying voltages to compensate for frequency drift during operation. This enables continuous frequency matching while preserving resolution through the use of smaller voltage adjustments on the second set.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If laser balancing is used to adjust mass or stiffness distribution, then manufacturing precision is improved, but adaptability to operational variations is reduced

Engineering Contradiction:
Improvefrequency balanceVSAvoidoperational variation compensation
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

Laser balancing is used during manufacturing to pre-adjust the mass or stiffness distribution of the annular resonator, reducing the initial frequency split between modes. This preliminary action establishes a good baseline frequency match that carries through operation, while the electrostatic balancing system provides ongoing adjustments for operational variations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system incorporates feedback control where the frequencies of the high and low frequency modes are continuously monitored during operation, and the balancing voltages on the electrode plates are dynamically adjusted to maintain frequency matching. This feedback mechanism compensates for operational variations that cannot be addressed by manufacturing alone.

Inventive Principle:
Principle #23Feedback

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 enhances the gyroscope's performance by maintaining frequency balance with improved resolution, regardless of the initial static balancing voltage, effectively addressing the limitations of prior art by dynamically adjusting frequencies to counteract operational and lifetime variations.

Implementation Method 1

a set of capacitive drive electrodes arranged to apply a voltage creating an electrostatic driving force to excite a primary cos nθ resonance along a primary axis at a primary frequency fP

Methodology Applied
Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

When the gyroscope is rotated around an axis normal to the plane of the annular resonator, Coriolis forces are generated which couple energy into a secondary response vibration along a secondary axis of motion

Methodology Applied
Scientific EffectCoriolis force: Coriolis Force

Implementation Method 3

a first set of digitally-controlled capacitive balancing electrodes arranged to apply a first static balancing voltage creating a static electrostatic balancing force to lower the frequency fH

Methodology Applied
Scientific EffectElectrostatic balancing force: Electrostatics

Data Source

PatentEP3486609B1Vibrating structure gyroscope with fine electrostatic frequency tuning
Publication Date: 2020.08.26 ATLANTIC INERTIAL SYST LTD
  • EP3486609B1 patent drawingFigure 1~2
  • EP3486609B1 patent drawingFigure 3A~3C
  • EP3486609B1 patent drawingFigure 4A~4B

AI summary

A vibrating structure gyroscope comprises an annular resonator 6 arranged to vibrate in a plane in response to electrostatic driving forces, a digitally-controlled first set of capacitive balancing electrodes 8 and a digitally-controlled second set of capacitive balancing electrodes 10. The second set of capacitive balancing electrodes 10 is arranged to dynamically apply a fine balancing voltage creating a dynamic electrostatic balancing force.