Asymmetric Target Inductive Sensor for Angular Position
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Solution Overview
Problem
Traditional inductive position sensors are large in size, making them unsuitable for space-constrained applications and sensitive to mechanical tolerances, especially when requiring a full 360-degree range.
Innovation Solution
An inductive position sensor with an asymmetric target that generates a reflected magnetic field pattern with both a first and second period, using receive coils to detect signals varying continuously with the target's position, allowing for robustness against mechanical misalignment without increasing sensor size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional inductive position sensors are designed with multiple electrical periods within one full mechanical rotation to improve robustness against mechanical tolerances, then measurement precision is improved, but device size increases significantly
Solution Approach 1:
The patent applies asymmetry by using a target with non-uniform magnetic properties (different magnetic permeability regions) instead of a symmetric multi-period target. This asymmetric target design generates position-dependent magnetic field variations that provide multiple electrical periods within a single mechanical rotation, thereby improving measurement precision and robustness against mechanical tolerances while keeping the sensor size compact.
Solution Approach 2:
The patent changes the magnetic parameter distribution in the target by introducing regions with different magnetic permeability values. This parameter variation creates the desired multi-period magnetic field pattern without requiring a large physical target, thus achieving high measurement precision within a compact sensor volume.
2Volume of moving object
If the sensor is miniaturized to fit space-constrained applications, then device size is reduced, but sensitivity to mechanical misalignment increases
Solution Approach 1:
The asymmetric target with varying magnetic permeability regions creates a magnetic field signature that is less sensitive to mechanical misalignment. The non-uniform magnetic properties provide distinctive position markers that maintain measurement reliability even when the sensor is miniaturized and more susceptible to alignment variations.
Solution Approach 2:
By varying the magnetic permeability parameters in different regions of the target, the patent creates a robust magnetic field pattern that maintains measurement reliability independent of mechanical alignment. This parameter variation ensures that the sensor can accurately detect position even at reduced sizes where misalignment effects are more pronounced.
3Adaptability or versatility
If a full 360-degree measurement range is implemented, then adaptability is improved, but robustness against mechanical tolerances deteriorates
Solution Approach 1:
The asymmetric target design with non-uniform magnetic permeability regions enables full 360-degree measurement range while maintaining robustness against mechanical tolerances. The varying magnetic properties create distinctive position-dependent field patterns throughout the entire rotation, providing both comprehensive coverage and tolerance immunity.
Solution Approach 2:
The patent achieves multi-functionality by designing a target that simultaneously provides full 360-degree coverage and multi-period magnetic field variations. This universal design allows the sensor to operate across the complete rotation range while maintaining the robustness benefits of multiple electrical periods within a single mechanical rotation.
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 provides increased robustness to mechanical tolerances and extends the range of the position sensor while maintaining high resolution, enabling miniaturization and improved accuracy in angular position detection.
Implementation Method 1
at least one transmit coil (120) for generating an alternating magnetic field
Implementation Method 2
asymmetric target (110) which is arranged such that, when excited by the alternating magnetic field of the at least one transmit coil (120), it generates a reflected magnetic field pattern
Implementation Method 3
at least one first receive coil (130) for inducing a first signal from the reflected magnetic field pattern and at least one second receive coil (140) for inducing a second signal from the reflected magnetic field pattern
Data Source
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AI summary
An inductive position sensor (100) for detecting the angular position of a rotatable target (110). The inductive position sensor (100) comprising: at least one transmit coil (120) for generating an alternating magnetic field; an asymmetric target (110) which is arranged such that, when excited, it generates a reflected magnetic field pattern with a first periodicity and a second periodicity, larger than the first periodicity: at least one first receive coil (130) configured to be responsive to the first periodicity, thus inducing a first signal; at least one second receive coil (140) configured to be responsive to the second periodicity, thus inducing a second signal; the inductive position sensor being configured for determining the angular position of the target from the first and second signal.