Magnetic Sensor Arrangement for Stray Field Resilient Position Detection
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Solution Overview
Problem
Existing magnetic field sensor configurations struggle to reliably detect discrete positional relationships between a magnetic field generator and a sensor arrangement with multiple sensors, often resulting in high sensitivity to interference fields and lack of redundancy for safety-critical applications.
Innovation Solution
A device and method utilizing at least three magnetic field sensors to generate multiple sensor signals, where a processing device calculates linear combinations of these signals to uniquely determine positional relationships, with the ability to switch between combinations to minimize stray field sensitivity and ensure accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple magnetic field sensors are used for redundancy in safety-critical applications, then reliability is improved, but sensitivity to interference fields increases
Solution Approach 1:
The sensor system is segmented into multiple discrete magnetic field sensors (at least three) arranged on a common carrier, each independently measuring the magnetic field. This segmentation allows for redundancy while enabling differential measurement strategies that suppress interference fields through signal combination.
Solution Approach 2:
Multiple sensor signals are merged through linear combinations calculated by the processing device. By combining signals from multiple sensors in specific mathematical relationships, the system achieves both redundancy for reliability and differential measurement for interference suppression, resolving the contradiction between these two requirements.
2Reliability
If discrete sensors are arranged on a common carrier for redundancy, then reliability is improved, but stray field suppression capability deteriorates
Solution Approach 1:
The system uses at least three discrete magnetic field sensors segmented and arranged on a common carrier, allowing independent measurement points that can be combined differentially to reject common-mode stray fields while maintaining redundancy for safety-critical applications.
Solution Approach 2:
The processing device changes the parameters of signal combination by calculating multiple different linear combinations of sensor signals. This allows dynamic adaptation to different operational conditions and optimization of stray field suppression while maintaining reliable position detection across various scenarios.
3Object-affected harmful factors
If linear combinations of sensor signals are calculated to reduce stray field sensitivity, then interference field sensitivity is reduced, but device complexity increases
Solution Approach 1:
The processing device performs multiple functions: it calculates linear combinations of sensor signals for stray field suppression, determines positional relationships, and verifies results through plausibility checks. This multi-functionality is achieved through a unified processing approach that handles all tasks using the same sensor array and computational framework.
Solution Approach 2:
The system implements feedback by verifying position determination results through plausibility checks using the calculated linear combinations. This feedback mechanism ensures accurate position detection while maintaining manageable complexity through systematic validation of measurement results.
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 reliable detection of discrete positional relationships with reduced interference field sensitivity, providing redundancy for safety-critical applications by using linear combinations of sensor signals to uniquely identify positions and verify results through plausibility checks.
Implementation Method 1
Hall sensor devices, which deliver an output signal that is proportional to an applied magnetic field
Implementation Method 2
sensors based on a magnetoresistive effect, such as AMR sensors (AMR=anisotropic magnetoresistive effect), GMR sensors (GMR=giant magnetoresistive effect), CMR sensors (CMR)=colossal magnetoresistive effect, or TMR sensors (TMR=magnetoresistive tunnel effect)
Data Source
AI summary
By a relative movement between an arrangement of at least three magnetic field sensors and a magnetic field generator, different discrete positional relationships can be produced between the same. A first signal is calculated as a first linear combination using at least two of three sensor signals. It is checked whether the first signal uniquely indicates one of the different discrete positional relationships. If yes, it is determined that the arrangement is located in the one discrete positional relationship. If no, a second signal is calculated as a second linear combination using at least two of the three sensor signals, at least one of which differs from the sensor signals used in the calculation of the first signal, and at least the second signal is used to determine in which of the different discrete positional relationships the arrangement is located relative to the magnetic field generator.