Magnetic Position Sensor Error Detection via Differential Angle Comparison

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Solution Overview

Problem

Magnetic position sensor systems lack effective error detection capabilities, often requiring trade-offs between accuracy, robustness against external disturbances, and cost, with existing solutions not adequately addressing these needs.

Innovation Solution

A magnetic position sensor system utilizing three magnetic sensors spaced apart to calculate angles based on magnetic field differences, providing error detection without increasing sensor footprint, and being insensitive to external disturbance fields and temperature variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If error detection capabilities are added to magnetic position sensor systems, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveerror detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the position measurement function into multiple independent sensor channels (first channel with first and second sensors, second channel with third and fourth sensors). Each channel can independently determine position, allowing cross-validation for error detection without requiring a completely integrated complex system. This segmentation enables reliability improvement through redundancy while keeping individual channel complexity manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent makes the sensor system multi-functional by enabling it to both determine position and detect errors using the same sensor array. The evaluation circuit processes signals from the sensors to perform dual functions: position calculation and error detection through comparison of results from different sensor channels. This universality adds reliability without proportionally increasing device complexity.

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

2Measurement precision

If multiple sensors are used to improve measurement accuracy and enable error detection, then measurement precision is improved, but area of the sensor device increases

Engineering Contradiction:
Improveposition measurement accuracyVSAvoidsensor device area
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent arranges sensors in a two-dimensional configuration (first and second sensors in a first arrangement, third and fourth sensors in a second arrangement) rather than linearly spacing them. This dimensional optimization allows the sensor array to achieve the necessary measurement precision for error detection while minimizing the footprint area. The spatial optimization in multiple dimensions enables accurate position determination with reduced sensor device area.

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

3Reliability

If redundancy is introduced for error detection, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveerror detection capabilityVSAvoidsensor channel complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the position determination function across multiple sensor channels into a unified evaluation process. The evaluation circuit combines signals from the first sensor channel (first and second sensors) and second sensor channel (third and fourth sensors) to determine position and perform error detection simultaneously. This merging approach achieves reliability through redundancy while avoiding the complexity of completely separate independent systems.

Inventive Principle:
Principle #5Merging (Combining)

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 accurate position determination and error detection with reduced sensor size and cost, maintaining high robustness against external disturbances and temperature variations.

Implementation Method 1

a first magnetic field component (e.g. Bx) oriented in the first direction (e.g. X), and a second magnetic field component (e.g. Bz) oriented in a second direction (e.g. Y; Z) perpendicular to the first direction

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP4206613B9Magnetic position sensor device, method and system, with error detection
Publication Date: 2025.01.01 MELEXIS TECHNOLOGIES SA
  • EP4206613B9 patent drawingFigure 1~2A
  • EP4206613B9 patent drawingFigure 2B~2C
  • EP4206613B9 patent drawingFigure 3~4

AI summary

A position sensor device comprising: a first, second and third magnetic sensor (S1, S2, S3) for measuring a first magnetic field component (Bx) oriented in the first direction (X), and a second magnetic field component (Bz) oriented in a second direction (Y; Z) perpendicular to the first direction; a processing circuit for determining a first and a second difference (ΔBx13, ΔBz13) of signals provided by the first and third sensor (S1, S3), and for determining and outputting a first angle (θmain) based on these differences; and for determining a third and a fourth difference (ΔBx12, ΔBz12) of signals provided by the second sensor (S2) and one (S1) of the first and the third sensor; and for determining a second angle (θaux12; θaux3) based on the third and the fourth difference, and for outputting the second angle and/or a diagnostic signal based on a comparison of the first and second angle.