Axisymmetric Coriolis Gyroscope Control for Lock-In-Free Dynamic Range

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Solution Overview

Problem

Existing axisymmetric Coriolis vibrating gyroscopes (CVGs) face limitations in dynamic range and lock-in effects, particularly in Force To Rebalance (FTR) and Whole Angle (WA) modes, which restrict their operational capabilities.

Innovation Solution

The introduction of a Force Angle Tracking (FAT) mode that combines pseudo-WA and pseudo-FTR modes, using a forcing control loop to maintain vibration direction at a variable setpoint, calculated from previous angular directions, allowing continuous output without dynamic range limitations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Force To Rebalance (FTR) mode is used, then lock-in effect is overcome, but dynamic range is restricted by rebalance force

Engineering Contradiction:

Improvelock-in effect preventionVSAvoiddynamic range

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from a static control approach (fixed setpoint in FTR mode) to a dynamic control approach where the setpoint angle varies continuously based on the difference between current and previous angular directions. This dynamic adaptation allows the system to maintain lock-in effect prevention while expanding dynamic range beyond FTR force limitations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent segments the angular rate measurement into two components: a high-rate component measured by the whole angle mode (geometric scale factor) and a low-rate component measured by the force to rebalance mode (FTR scale factor). This segmentation allows each mode to operate in its optimal range, combining their advantages to achieve both lock-in prevention and extended dynamic range.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If Whole Angle (WA) mode is used, then dynamic range is extended, but lock-in effect occurs at low angular rates

Engineering Contradiction:

Improvedynamic rangeVSAvoidlock-in effect

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the setpoint for the forcing control loop is continuously updated based on the difference between the current angular direction and the previous angular direction. This feedback prevents the lock-in effect by ensuring the setpoint adapts to the actual rotation, while the forcing control maintains the vibration direction tracking.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent merges the Whole Angle mode and Force To Rebalance mode into a unified operating mode that combines their advantages. The WA mode provides the geometric scale factor for high dynamic range, while the FTR mode provides the force-based measurement for low rates, and both are integrated through the variable setpoint forcing control.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If FTR mode operates with fixed setpoint, then control is simplified, but continuous output is lost at low rates

Engineering Contradiction:

Improvecontrol complexityVSAvoidcontinuous output

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent makes the setpoint dynamic rather than fixed, updating it continuously based on the difference between current and previous angular directions. This dynamic setpoint ensures continuous output across all rotation rates while maintaining relatively simple forcing control implementation.

Inventive Principle:

Principle #15Dynamics

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

FAT mode enables a robust gyroscope operation with continuous output and unlimited dynamic range, overcoming the limitations of FTR and WA modes without requiring hardware changes.

Implementation Method 1

a resonator configured to vibrate in a standing wave

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

When the gyroscope experiences angular rotation, the Coriolis effect induces secondary vibrations orthogonal to the original oscillation plane

Methodology Applied

Scientific EffectCoriolis effect: Coriolis Force

Implementation Method 3

In one example the coupling between the resonator and the control elements is capacitive

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 4

In another example the coupling between the resonator and the control elements is piezo-electric

Methodology Applied

Scientific EffectPiezo-electric effect: Piezoelectric Effect

Data Source

PatentUS20260043652A1Operational mode for axisymmetric coriolis vibrating gyroscopes

Publication Date: 2026.02.12 ISRAEL AEROSPACE IND LTD

AI summary

A new axisymmetric Coriolis vibrating gyroscope includes a resonator configured to vibrate in a standing wave; a plurality of control elements; and a control circuitry, configured to iteratively control said control elements so as to maintain an angular direction of said vibration at a current setpoint; determine an angular direction of said vibration of said resonator from respective readings of at least two of said control elements; calculate a total angular rate; and update said setpoint to an angular direction of said vibration determined in a previous iteration