Circular Magnetic Sensor Array for Angular Displacement Accuracy
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Solution Overview
Problem
Conventional magnetic field sensor arrangements face accuracy issues in measuring angular displacement due to uneven magnetic field intensity distribution and lateral displacement of the magnetic source, leading to deviations in determined rotation angles.
Innovation Solution
A sensor arrangement with a circularly shaped configuration of magnetic field sensors and an evaluation circuit that processes digital sensor values to determine rotation angles using interpolation, curve fitting, and trigonometric functions, accounting for the magnetic field's shape and intensity, allowing for precise measurement of angular displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic field sensor arrangements are used to measure angular displacement, then the measurement can be performed with a simple circular sensor array, but the accuracy is impaired due to uneven magnetic field intensity distribution and lateral displacement of the magnetic source
Solution Approach 1:
The patent applies parameter changes by using multiple reference values at different magnetic field intensities (first reference value at maximum intensity, second reference value at minimum intensity) instead of a single reference value. This allows the evaluation circuit to select appropriate reference values based on the actual magnetic field conditions, compensating for uneven field distribution and lateral displacements while maintaining measurement accuracy without requiring complex hardware modifications
Solution Approach 2:
The patent segments the measurement process by dividing it into multiple evaluation steps: determining multiple reference values at different intensity levels, selecting appropriate reference values based on current conditions, and performing separate evaluations for each reference value. This segmentation allows the system to handle complex magnetic field variations through a series of simpler, manageable evaluation steps, improving accuracy without overall system complexity
2Adaptability or versatility
If the magnetic source is laterally displaced with respect to the sensor center, then the sensor arrangement can still operate, but measurement errors increase due to deviation from the ideal centered position
Solution Approach 1:
The patent applies preliminary action by pre-determining multiple reference values at different magnetic field intensities before the actual measurement process. These reference values are established in advance to account for potential lateral displacements, allowing the evaluation circuit to select the appropriate reference value that corresponds to the actual magnetic field conditions. This preliminary preparation enables the system to compensate for displacement errors without requiring real-time complex calculations or hardware adjustments
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 enhances the accuracy of angular displacement measurement by compensating for irregularities in the magnetic field and lateral displacements, providing a more precise determination of the rotation angle.
Implementation Method 1
magnetic field sensors for measuring a magnetic field intensity
Data Source
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Figure 7A~7B
AI summary
A sensor arrangement comprises a plurality of magnetic field sensors (MS0 to MS15) arranged along a circularly shaped circumference (CIR1), each of the magnetic field sensors (MS0 to MS15) configured to provide a sensor signal corresponding to a magnetic field intensity. An evaluation circuit (EC) is provided comprising a plurality of input channels, each of the input channels configured to receive a digital sensor value (H0 to H15) derived from a respective one of the sensor signals. The evaluation circuit (EC) is configured to determine a rotation angle (Φ) as a function of a subset of the digital sensor values (H0 to H15) received. The sensor arrangement can be used with a rotatable diametrically magnetized magnetic source (MAG).