Position Sensor Master Nonius Tracks Crosstalk Reduction

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Solution Overview

Problem

Conventional position sensing systems using multipolar magnets improve angular resolution and accuracy but lose information about absolute angular position, and existing solutions with two magnetic tracks suffer from high crosstalk, requiring separate chips or larger sensor areas, increasing cost and complexity.

Innovation Solution

A position sensing system with a first and second magnetic track, where the first track generates a stronger magnetic field, and the second track's field has a negligible contribution to the first sensor's readings, allowing for compact integration of sensors without crosstalk compensation, using a configuration where the first sensor is closer to the stronger track and the second sensor is positioned to minimize overlap with the weaker track.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If two magnetic tracks are used to reconstruct full 360° range, then absolute angular position information is recovered, but crosstalk between fields increases

Engineering Contradiction:

Improveabsolute angular position informationVSAvoidcrosstalk between fields

Core Design Contradiction:

Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by making the first magnetic track have a different magnetic field strength characteristic than the second track. Specifically, the first track is designed to generate a stronger magnetic field than the second track, creating localized field strength differences that enable the first sensor to predominantly detect the first track's signal while minimizing interference from the second track.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs asymmetry by creating an asymmetric magnetic field distribution between the two tracks. The first track generates a stronger field than the second track, and the sensors are positioned at asymmetric distances from each track. This asymmetric configuration allows the system to distinguish between tracks and reduce crosstalk while maintaining absolute position information.

Inventive Principle:

Principle #4Asymmetry

2Measurement precision

If tracks are physically separated to reduce crosstalk, then measurement accuracy improves, but device area increases

Engineering Contradiction:

Improveangular position accuracyVSAvoidsensor chip area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent changes the magnetic field strength parameter of the different tracks. By designing the first track to generate a stronger magnetic field than the second track, the system can achieve effective track discrimination and crosstalk reduction without requiring large physical separations, thus maintaining compact device area while improving measurement precision.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If integrated sensors are used, then device complexity is reduced, but crosstalk between tracks increases

Engineering Contradiction:

Improvesensor integration levelVSAvoidcrosstalk between fields

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating localized field strength differences between tracks. The first track generates a stronger field in its local region, allowing integrated sensors to predominantly detect the intended track's signal while minimizing pickup from adjacent tracks, thus enabling high integration without excessive crosstalk.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The asymmetric field strength design allows integrated sensors positioned at specific asymmetric locations to selectively detect signals from specific tracks. This asymmetry enables compact integration while maintaining signal discrimination capability.

Inventive Principle:

Principle #4Asymmetry

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 enables accurate detection of the magnetic structure's position without losing absolute position information, reduces crosstalk, and allows for a compact, cost-effective, and integrable sensing system with reduced computational load, improving angular position sensing accuracy and resolution.

Implementation Method 1

a first magnetic track (601) comprising a first number of multipoles for generating a magnetic field and a second magnetic track (602) for generating a magnetic field

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

The magnetic flux density generated by the first and second magnetic tracks follow a ratio of two or more

Methodology Applied

Scientific EffectMagnetic flux density: Magnetic Field

Data Source

PatentUS20230296416A1Position sensor with master and nonius tracks

Publication Date: 2023.09.21 MELEXIS TECHNOLOGIES SA

AI summary

A sensing system and a method for sensing position include a first magnetic track comprising a first number of multipoles for generating a magnetic field solidarily fixed to a second magnetic track for generating a magnetic field and a second sensor for sensing magnetic field, forming a magnetic structure. At least two sensors are included. The first sensor is positioned proximal to the first magnetic track, closer to the first magnetic track than to the second magnetic track. The second sensor is positioned between the first sensor and the second magnetic track. The distance between the first sensor and the second magnetic track is larger than the distance between the second sensor and the second magnetic track. The magnetic flux density generated by the first and second magnetic tracks follow a ratio of two or more.