Inductive Position Detector Winding Arrangement

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Solution Overview

Problem

Existing inductive displacement detectors face challenges with accuracy due to imperfections and non-linearities caused by manufacturing irregularities, capacitive coupling, and cross-talk between windings, making high-accuracy measurements difficult and time-consuming, especially when requiring >1000 correction points along the measurement scale.

Innovation Solution

The design incorporates a configuration with first and second antenna winding arrangements and target winding arrangements that are orthogonally spaced, featuring coarser and finer pitch receive winding loops with opposite polarities, non-overlapping electrical connections, and a shorted turn to prevent energy coupling, along with a conductive or magnetically permeable surface to reduce noise, and an epoxy encapsulant for robustness, enhancing signal-to-noise ratio and measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional single antenna winding arrangement is used, then device complexity is low, but measurement precision deteriorates due to manufacturing irregularities and non-linearities

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidwinding arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The antenna winding arrangement is divided into a first antenna winding arrangement and a second antenna winding arrangement with different pitch characteristics. The first arrangement provides coarse positioning while the second arrangement provides fine positioning, together achieving high measurement precision without requiring excessive complexity in any single component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a second antenna winding arrangement with different pitch characteristics (coarser pitch) alongside the first arrangement (finer pitch). This adds a dimensional aspect to the measurement system, allowing coarse and fine measurements to be combined, thereby achieving high accuracy without proportionally increasing device complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If multiple antenna winding arrangements with different pitch are used, then measurement accuracy improves, but device complexity increases

Engineering Contradiction:
Improvedisplacement measurement accuracyVSAvoidmultiple winding arrangements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the functionality of multiple antenna winding arrangements with different pitch characteristics into a unified detector system. The first and second antenna winding arrangements work together with the target winding arrangements to provide both coarse and fine displacement measurements, achieving high accuracy while managing complexity through integrated design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The multiple antenna winding arrangements serve different functions within the same system: the first arrangement handles coarse displacement measurement while the second arrangement handles fine displacement measurement. This multi-functionality allows the system to achieve high measurement accuracy across different scales without requiring separate systems for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If calibration with many correction points is performed, then measurement accuracy improves, but time consumption increases

Engineering Contradiction:
Improvemeasurement linearityVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary action by designing the winding arrangements with specific pitch relationships and polarity configurations that inherently reduce non-linearities. This preliminary design consideration reduces the need for extensive post-manufacturing calibration, thereby improving measurement linearity while minimizing calibration time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes key parameters of the winding arrangements, specifically the pitch relationships between first and second antenna windings and the polarity configuration of target winding loops. These parameter changes are optimized to minimize measurement non-linearities, reducing the correction points needed during calibration and thereby reducing calibration time while maintaining high accuracy.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If electrical connections are placed in overlapping areas, then manufacturing is simpler, but measurement accuracy deteriorates due to noise and interference

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidconnection layout
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent extracts electrical connections from overlapping areas where they would cause interference. By positioning connections in non-overlapping regions, the design eliminates noise and interference sources that would degrade signal quality, thereby improving measurement precision while maintaining ease of manufacture through clear spatial separation.

Inventive Principle:
Principle #2Taking out (Extraction)

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 configuration significantly improves measurement accuracy and reduces errors, allowing for high-resolution displacement measurements with reduced noise and improved robustness, enabling precise detection even in hostile environments.

Implementation Method 1

use the principle of mutual inductance whereby one or more transmit windings is energized with an AC signal to generate an AC magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a passive resonant circuit incorporating at least first and second target winding arrangements in series with a capacitor

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

receive windings are arranged to couple with the transmit windings. The amount of coupling varies as the displacement of a passive inductive target varies relative to the windings

Methodology Applied
Scientific EffectMutual inductance: Electromagnetic Induction

Data Source

PatentEP3221667B3Inductive position detector
Publication Date: 2024.09.11 ZETTLEX UK LTD
  • EP3221667B3 patent drawingFigure 1
  • EP3221667B3 patent drawingFigure 2
  • EP3221667B3 patent drawingFigure 3

AI summary

An inductive position detector with a first and a second body, at least one of said bodies being displaceable relative to the other along a measurement path wherein said first body comprises one or more antenna windings forming a first arrangement of windings and said second body comprises a passive resonant circuit incorporating one or more target windings in series with a capacitor; said circuit covering at least in part said first arrangement; characterised in that said first body comprises an additional winding arrangement disposed along at least part of said measurement path; said additional winding arrangement being spaced from said first arrangement of windings; and said second body comprises an additional winding arrangement covering at least in part said additional winding arrangement of said first body.