Hybrid Position Sensor Combining Magnetic and Inductive Transducers
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Solution Overview
Problem
Magnetic and inductive position sensors face accuracy degradation when extending their range to 360° due to reduced signal-to-noise ratio and increased parasitic sensitivity to stray fields, leading to amplified electrical and mechanical errors.
Innovation Solution
A hybrid position sensor system that combines a magnet-based main transducer with a higher resolution and a limited range, and an inductive support transducer with a lower resolution and larger range, using a combiner to integrate signals for enhanced accuracy and range extension without significantly degrading the signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the range of a position sensor is extended to 360°, then the sensor can cover the full rotation range, but the signal-to-noise ratio is reduced and measurement precision degrades
Solution Approach 1:
The sensor system is segmented into multiple independent sensing channels (e.g., three inductive channels at 120° intervals and magnetic sensors). Each channel operates within its optimal range with high signal-to-noise ratio, and the channels are combined to achieve full 360° coverage. This segmentation allows each component to maintain high precision while the system as a whole achieves extended range.
2Adaptability or versatility
If the range of a position sensor is extended to 360°, then the sensor can cover the full rotation range, but parasitic sensitivity to stray fields increases
Solution Approach 1:
The patent converts the harmful effect of stray fields into a beneficial feature by using magnetic sensors that are inherently immune to non-magnetic interference. The magnetic sensing channels detect only magnetic field changes from the target magnet, automatically rejecting electromagnetic interference and stray fields that affect traditional inductive sensors. This transforms the limitation of magnetic sensors (inability to detect non-magnetic targets) into an advantage for stray-field immunity.
3Adaptability or versatility
If the range of a position sensor is extended to 360°, then the sensor can cover the full rotation range, but electrical and mechanical errors are amplified
Solution Approach 1:
The patent merges multiple sensing technologies (inductive and magnetic) with different error characteristics into a unified sensor system. Inductive channels provide accurate position data within their limited range, while magnetic channels provide complementary data for full 360° coverage with immunity to electromagnetic interference. The combination algorithm integrates these signals to produce a final position measurement that achieves both extended range and high precision, preventing error amplification by leveraging the strengths of each technology.
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 hybrid sensor achieves improved accuracy and extended range up to 360° while maintaining a high signal-to-noise ratio, reducing stray field interference, and minimizing incremental costs through a cost-optimized design.
Implementation Method 1
the first technology is magnet based and is detecting the magnet
Implementation Method 2
the second technology is an inductive technology and is detecting the conductive target
Data Source
AI summary
A hybrid position sensor for determining the position of a hybrid target includes a main transducer for obtaining a first signal indicative for a position of the hybrid target within a first range and with a first resolution using a first or second technology; a support transducer for obtaining a second signal indicative for the position of the hybrid target within a second range and with a second resolution using the second technology if the main transducer is using the first technology and vice versa, wherein the first range is smaller than the second and the first resolution is higher than the second, and wherein the first technology is magnet based and the second technology is an inductive technology; a combiner for combining the obtained first signal and second signal to determine the position of the hybrid target.