Magnetometer-Based Respiratory Motion Measurement

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Solution Overview

Problem

Current respiratory monitoring devices are obtrusive, costly, and not conducive to continuous or long-term monitoring, especially for patients with certain conditions, as they often require complex infrastructure and cannot accurately measure tidal volume changes or handle patient movement, limiting their use for home monitoring.

Innovation Solution

A method and apparatus that utilize a sensor to measure oscillatory motion by determining the angle of rotation of a vector parameter relative to a predominant direction, allowing for continuous, unobtrusive, and cost-effective respiratory monitoring without the need for restraining apparatus or complex infrastructure, using a processor to analyze signals from a vector parameter, such as a gravitational or magnetic field, to calculate angular velocity and respiratory flow rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If obtrusive constrictive belts with strain gauges are used to measure respiration, then measurement precision is improved, but ease of operation deteriorates due to patient discomfort and inability to move freely

Engineering Contradiction:
Improverespiration measurement precisionVSAvoidpatient mobility and comfort
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces mechanical strain gauges and physical contact sensors with a magnetic field-based sensing system. A magnet is attached to the patient's chest, and a magnetometer sensor detects changes in magnetic field orientation as the chest moves during respiration. This eliminates the need for constrictive belts and mechanical contact, allowing free patient movement while maintaining measurement accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If complex infrastructure is used for respiration monitoring, then measurement precision is improved, but device complexity increases making home monitoring difficult

Engineering Contradiction:
Improverespiration measurement precisionVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential measurement function from complex medical infrastructure by using a simple magnetometer sensor that detects magnetic field orientation changes. This standalone sensor can operate independently without requiring complex signal processing equipment, ventilation systems, or specialized medical infrastructure, enabling simple home monitoring while maintaining measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a magnetic field as a proxy or copy of the physical chest movement. Instead of directly measuring mechanical displacement with complex sensors, it captures the orientation changes of the magnetic field caused by chest motion, simplifying the measurement system while preserving the essential respiratory information.

Inventive Principle:
Principle #26Copying

3Measurement precision

If stationary patient monitoring is required for accurate measurements, then measurement precision is improved, but ease of operation deteriorates due to inability to allow patient movement

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidpatient movement freedom
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent makes the measurement system dynamic by detecting changes in magnetic field orientation rather than relying on fixed positional measurements. The magnetometer continuously tracks the orientation of the magnetic field vector as the patient moves and breathes, allowing accurate respiration measurement during patient movement rather than requiring the patient to remain stationary.

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

Enables precise and accurate measurement of respiratory parameters like respiratory flow rate and tidal volume changes, allowing for continuous, low-cost, and remote monitoring of respiratory health without the need for complex equipment or initial precise sensor placement, effectively distinguishing valid measurement signals from noise.

Implementation Method 1

a sensor configured for attachment to a body part that undergoes oscillatory motion during respiration so as to move with the body part; wherein the sensor is arranged to provide signals indicative of a measurement of a direction of a vector parameter

Methodology Applied
Scientific EffectGravitational field measurement: Gravitation

Implementation Method 2

a measured direction of the vector parameter (a t) of one of the plurality of measurements of the direction of the vector parameter, and the predominant measured direction of the vector parameter (a t)

Methodology Applied
Scientific EffectMagnetic field measurement: Magnetic Field

Data Source

PatentEP2563218B1Method, apparatus, computer program and system for measuring oscillatory motion
Publication Date: 2018.11.21 THE UNIV COURT OF THE UNIV OF EDINBURGH
  • EP2563218B1 patent drawingFigure 1~2
  • EP2563218B1 patent drawingFigure 3
  • EP2563218B1 patent drawingFigure 4

AI summary

A method, apparatus, computer program, system and device for measuring oscillatory motion comprising: receiving a plurality of signals related to a plurality of measurements of a direction of a vector parameter (at-1, at); determining a predominant measured direction of the vector parameter (āt) based on the plurality of measurements of the direction of the vector parameter; determining an angle of rotation (φt) between: a measured direction of the vector parameter (at) of one of the plurality of measurements of the direction of the vector parameter, and the predominant measured direction of the vector parameter (āt).