Ferrous Distance Detection Using Magnetometer Ratios

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Solution Overview

Problem

Existing methods using gradiometers to determine magnetic field gradients are limited in accurately measuring the distance and strength of ferrous materials due to interference from ambient magnetic fields and require complex setups with fixed distances between magnetometers.

Innovation Solution

A method employing a plurality of magnetometers spaced at varying distances from a ferrous material, with a primary magnetometer and others detecting absolute magnetic fields, forming ratios of sensor readings and inversely cubed distances to calculate the distance and relative field strengths, and using virtual magnetometers and magnetic shielding to minimize ambient noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If gradiometers with fixed distance magnetometers are used to measure magnetic field gradients, then the measurement setup is simplified, but the accuracy of distance and strength determination of ferrous materials deteriorates due to ambient magnetic field interference

Engineering Contradiction:

Improvemagnetometer setup complexityVSAvoiddistance and strength determination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system divides the measurement task into multiple independent magnetometer measurements taken at different known distances from the ferrous material. Each magnetometer provides a separate measurement that is later processed through ratio calculations to eliminate ambient field interference and determine both distance and strength independently.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If magnetometers are spaced at varying distances from the ferrous material, then the precision of distance and field strength determination improves, but the device complexity and measurement setup difficulty increase

Engineering Contradiction:

Improvedistance determination accuracyVSAvoidmagnetometer spacing configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system varies the distance parameter of magnetometers from the ferrous material to improve measurement precision. By taking measurements at multiple known distances and using ratio calculations, the system can determine both the distance to and strength of the ferrous material with higher accuracy than fixed-distance configurations.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multiple magnetometers are used to detect absolute magnetic fields, then the ability to cancel ambient noise and determine distance improves, but the quantity of equipment and system complexity increases

Engineering Contradiction:

Improveambient noise cancellation capabilityVSAvoidnumber of magnetometers

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The system uses multiple magnetometer measurements as feedback to calculate ratios that eliminate ambient field interference. By comparing measurements from magnetometers at different distances and using the known distance ratios, the system can determine the unknown distance to the ferrous material while canceling out ambient magnetic field effects.

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 allows for precise determination of the distance and relative magnetic field strengths of ferrous materials by canceling ambient noise and increasing detection area, enabling effective measurement even with complex magnetic field configurations.

Implementation Method 1

Magnetometers measure the strength and direction of the ambient magnetic field as well as magnetic fields from other sources, such as ferrous materials

Methodology Applied

Scientific EffectMagnetic field detection: Magnetometer

Implementation Method 2

forming a second ratio of the differences in inversely cubed distances to the ferrous material from the primary magnetometer to inversely cubed distances to the ferrous material from the other magnetometers

Methodology Applied

Scientific EffectInverse cube law for magnetic field: Magnetic Field

Data Source

PatentUS8314608B2Method of determining distance to a ferrous material

Publication Date: 2012.11.20 CATERPILLAR SARL

AI summary

In one aspect of the present invention a method of determining a distance to a ferrous material comprises providing a plurality of magnetometers spaced at varying distances from a ferrous material, detecting a ferrous material with each of the plurality of magnetometers individually, establishing one of the plurality of magnetometers as a primary magnetometer, obtaining sensor readings from each of the plurality of magnetometers, forming a first ratio of the differences in the sensory readings of the primary magnetometer to the sensory readings of the other magnetometers, forming a second ratio of the differences in inversely cubed distances to the ferrous material from the primary magnetometer to inversely cubed distances to the ferrous material from the other magnetometers, setting the first ratio and the second ratio equal to each other, and calculating the distance to the ferrous material from the plurality of magnetometers.