Magnetic Angle Position Sensor 3D Hall-Effect Crosstalk Reduction
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Solution Overview
Problem
Existing contactless rotary shaft position sensors face limitations in accuracy due to crosstalk errors and temperature drift, particularly when measuring multiple turns of a shaft, as they rely on fixed gear ratios and two-pole magnets which can lead to inaccuracies proportional to the gear ratio.
Innovation Solution
A magnetic angle position sensor utilizing a 3D Hall-effect sensor to measure orthogonal and parallel magnetic field components (Bx, By, Bz) from two strategically positioned toroidal magnets, allowing for precise identification of magnet positions and minimizing crosstalk through calibration, thereby enhancing accuracy and compensating for temperature effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed gear ratios and two-pole magnets are used for contactless rotary shaft position sensing, then device complexity is reduced, but measurement precision deteriorates due to crosstalk errors and temperature drift
Solution Approach 1:
The patent transitions from measuring only radial magnetic field components (2D plane) to measuring three-dimensional magnetic field components including axial direction (3D space). The 3D Hall effect sensor measures Bx, By, and Bz components, where Bz represents the axial component that provides additional dimensional information for distinguishing magnet positions and reducing crosstalk errors.
Solution Approach 2:
The patent segments the magnetic field measurement into three independent orthogonal components (Bx, By, Bz) measured by the 3D Hall effect sensor. This segmentation allows independent analysis and compensation of each field component, enabling more precise determination of magnet positions and reducing measurement errors through component-wise processing.
2Measurement precision
If 3D magnetic field measurement with 3D Hall effect sensor is implemented, then measurement precision improves by reducing crosstalk errors, but device complexity increases
Solution Approach 1:
The 3D Hall effect sensor performs multiple functions simultaneously: it measures three orthogonal magnetic field components (Bx, By, Bz), determines positions of multiple magnets, compensates for temperature effects, and reduces crosstalk errors. This multi-functionality consolidates what would otherwise require multiple separate sensors or measurement systems into a single device.
Solution Approach 2:
The patent utilizes temperature as an additional measurement parameter to compensate for thermal drift effects. By monitoring temperature variations and applying compensation algorithms, the system maintains measurement precision across different thermal conditions, effectively using parameter changes to improve robustness rather than allowing them to degrade performance.
3Ease of manufacture
If two-pole magnets with fixed gear ratios are used, then ease of manufacture is improved, but reliability deteriorates due to inaccuracies proportional to gear ratio
Solution Approach 1:
The patent implements feedback through calibration procedures where the system measures actual magnetic field positions and compares them against expected positions based on gear ratios. Temperature compensation feedback loops continuously adjust measurements to account for thermal drift, and the system uses measured Bz components to verify and correct magnet position determinations, thereby compensating for manufacturing tolerances in gear ratios.
Solution Approach 2:
The patent performs preliminary calibration actions during system initialization or manufacturing to establish baseline relationships between magnet positions and sensor readings. This preliminary characterization of the specific hardware configuration allows the system to compensate for fixed manufacturing variations and gear ratio inaccuracies throughout operation, improving reliability without requiring higher precision manufacturing.
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 significantly reduces crosstalk errors and improves accuracy by using a 3D magnetic field measurement, enabling precise position sensing of multiple turns with minimal temperature drift impact, thus enhancing the overall performance of the magnetic angle position sensor.
Implementation Method 1
A magnetic angle position sensor utilizing a 3D Hall-effect sensor to measure orthogonal and parallel magnetic field components (Bx, By, Bz) from two strategically positioned toroidal magnets
Data Source
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AI summary
A method and an apparatus is claimed, involving measuring magnetic field components (Bx, By, Bz) associated with magnets (120, 122) contained in a magnetic angle position sensor (100) by means of a sensing device (130); identifying a first and a second angle based on the measured magnetic field components, the first angle representing an angular position associated with a first magnet (120) and the second angle representing an angular position associated with a second magnet (122); and identifying positions of the first and second magnets based on the identified first and second angles.