Thermal Coefficients for MR Array Position Transducer Compensation

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Solution Overview

Problem

Magnetoresistive sensors, particularly anisotropic magnetoresistive (AMR) sensors in array configurations, suffer from errors due to thermal expansion, which alters the relative position of the sensors and the magnet being sensed, leading to inaccuracies in position detection algorithms.

Innovation Solution

The implementation of thermal compensation methodologies and systems that automatically amplify and calibrate signals from magnetoresistive sensing components, predicting physical alterations over temperature to compensate for thermal expansion and reduce associated errors, including the use of thermal coefficients (TCN and TCT) to adjust for centerline-to-centerline distances and relative positions between sensors and the magnet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetoresistive sensors are used in array configurations for position detection, then position detection capability is improved, but thermal expansion causes errors in sensor positioning and measurement accuracy deteriorates

Engineering Contradiction:
Improveposition detection accuracyVSAvoidmeasurement reliability under temperature variation
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by introducing thermal compensation coefficients (TCN for nudge/spacing and TCT for tare/offset) that adjust sensor position parameters based on temperature. The system calculates compensated sensor positions using formulas that incorporate these thermal coefficients to counteract thermal expansion effects, thereby maintaining measurement accuracy across temperature variations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback through temperature compensation algorithms that continuously adjust sensor position parameters based on measured or predicted temperature changes. The system uses feedback loops to calculate and apply compensation values to nudge and tare parameters, ensuring that position detection remains accurate despite thermal expansion of the sensor array and magnet.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If thermal compensation is implemented to reduce temperature-induced errors, then measurement precision is improved, but device complexity increases due to additional compensation mechanisms

Engineering Contradiction:
Improveposition detection accuracyVSAvoidcompensation system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-determining thermal compensation coefficients (TCN and TCT) through calibration procedures performed before actual operation. These coefficients are stored and automatically applied during position detection, eliminating the need for real-time complex calculations and reducing runtime computational complexity while maintaining high measurement precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent simplifies the compensation system by changing parameters to a practical level - using linear thermal expansion models with fixed coefficients rather than complex real-time physical simulations. This approach achieves sufficient compensation accuracy with minimal computational overhead and simple implementation.

Inventive Principle:
Principle #35Parameter changes

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 significantly reduces temperature-induced errors, achieving improved accuracy in linear and rotary sensing applications by compensating for thermal expansion and its effects on sensor positioning, resulting in a 60% reduction in least significant bit (LSB) errors across temperature changes.

Implementation Method 1

Magnetoresistive (MR) array technology is utilized in a variety of commercial, consumer and industrial detection applications

Methodology Applied
Scientific EffectMagnetoresistive effect: Magnetoresistance

Implementation Method 2

thermal expansion physically alters the relative position of the magnetoresistive sensors not only with respect to themselves but with respect to the magnet being sensed

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP1929247B1Thermal coefficients of nudge compensation and tare compensation for linear and rotary mr array position transducers
Publication Date: 2016.02.03 HONEYWELL INTERNATIONAL INC
  • EP1929247B1 patent drawingFigure 1
  • EP1929247B1 patent drawingFigure 2
  • EP1929247B1 patent drawingFigure 3

AI summary

Methods and systems are disclosed in which the errors caused by thermal expansion in magnetoresistive position transducers are reduced by predicting the physical alterations over temperature between centerline-to-centerline distances of particular magnetoresistive sensors or components within a magnetoresistive array and also between such an array and a magnet being sensed caused by thermal expansion.