3D Hall Sensor Monotonic Position Signal Correction
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Solution Overview
Problem
Existing sensors for non-contact magnetic detection of linear relative movements in pneumatic cylinders are limited by their length matching the measuring range, requiring complex control systems, being expensive, and suffering from slow measurement due to signal noise, and are not adaptable to both axially and diametrically magnetized magnets.
Innovation Solution
A sensor using a single element that detects perpendicular magnetic field components, employing TMR technology for low noise and high resolution, with an evaluation unit that corrects the position signal using a truth table and weighting factors to achieve a monotonic output over the entire measuring range, and is compatible with both magnetization types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a line of many Hall elements is used along the measuring section to achieve high precision, then measurement precision is improved, but device complexity increases and sensor length must correspond to measuring range
Solution Approach 1:
The patent combines multiple Hall elements into a single 3D Hall element that integrates three orthogonal Hall sensors in one package. This merging reduces the number of components from multiple discrete Hall elements to a single integrated sensor, thereby reducing device complexity while maintaining measurement precision through the use of vector mathematics to calculate position from the three orthogonal field components.
Solution Approach 2:
The patent replaces the mechanical/physical arrangement of multiple discrete Hall elements along the measuring section with a mathematical evaluation system. Instead of physically distributing many sensors, the invention uses a single 3D Hall element with mathematical algorithms (vector calculations, arctan functions) to determine position, substituting physical complexity with computational processing.
2Device complexity
If 3D Hall elements with digital interface are used, then device complexity is reduced, but measurement speed decreases due to signal noise
Solution Approach 1:
The patent implements signal filtering and evaluation algorithms that process the raw Hall voltage signals from all three components. The evaluation unit applies mathematical transformations and noise reduction techniques to the measured signals before determining position, effectively filtering out high-frequency noise while preserving the positional information, thereby maintaining fast measurement speeds despite the use of integrated 3D Hall elements.
3Measurement precision
If Hall elements are positioned at fixed distance to measure radial component, then measurement precision is improved, but the solution becomes expensive due to many required components
Solution Approach 1:
The patent merges three separate Hall element measurements into a single 3D Hall element that provides all three orthogonal field components simultaneously. This consolidation reduces the component count from multiple discrete Hall elements to one integrated sensor, thereby reducing cost and complexity while maintaining the precision needed for accurate position determination through vector mathematics.
Solution Approach 2:
The single 3D Hall element performs multiple functions that would otherwise require separate sensors: it measures all three orthogonal magnetic field components, provides spatial orientation information, and enables position calculation along the entire measuring range. This multi-functionality eliminates the need for multiple specialized components, reducing both quantity and cost.
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
The solution allows for a compact sensor design with high resolution, fast measurement rates, and high interference suppression, enabling accurate position detection across varying cylinder lengths and magnetization types, while being cost-effective and adaptable to different magnetic conditions.
Implementation Method 1
The sensor element is an angle sensor based on TMR technology. The magnetic tunnel resistance (English tunnel magnetoresistance, TMR) or TMR effect is a magnetoresistive effect that occurs in magnetic tunnel junctions
Implementation Method 2
The Hall elements are positioned at a fixed distance and can each measure a radial component of the magnetic field in a small area to the left and right of the respective Hall element center
Data Source
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AI summary
Sensor for non-contact magnetic detection of linear relative motion of a sensor magnet (2) along a measuring section (3) with at least one sensor element (4), wherein the sensor element (4) detects two mutually perpendicular components (6, 7) of a magnetic field (5) of the sensor magnet, wherein the sensor element (4) and the sensor (1) are shorter than the measuring section (3), wherein a first component (6) is an axial component (Bx), wherein a second component (7) is a radial component (By), wherein an evaluation unit (9) is provided, wherein the axial component (Bx) and the radial component (By) can be evaluated in the evaluation unit (9) according to a mathematical function, wherein the mathematical function is ARCTAN (radial component/axial component) or ARCTAN (axial component/radial component).wherein a sectionally monotonic position signal (10) with a value (11) of a value range (12) for each position (13) along the measuring section (3) of the encoder magnet (2) is formed, wherein the evaluation unit is configured to correct the position signal (10) in at least one area (14) of the measuring section (3) with a constant correction value (21), so that a monotonic position signal (10) with a monotonic value range (12) is formed over the entire measuring section (3).