Radial-Fin Target Structure for Inductive Angular-Position Sensing
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Solution Overview
Problem
Existing inductive angular-position sensors face challenges in achieving accurate and efficient angular-position sensing due to limitations in target design and magnetic coupling, leading to inefficiencies in rotor position sensing and increased weight and energy consumption.
Innovation Solution
The development of targets and sense coils with specific shapes and orientations that enhance magnetic coupling disruption, allowing for more accurate angular-position sensing by generating sinusoidal amplitude-modulated signals, reducing target size and weight, and increasing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional target designs are used in inductive angular-position sensors, then magnetic coupling is maintained, but measurement precision and sensitivity are reduced
Solution Approach 1:
The target is divided into multiple discrete conductive elements (fins) arranged radially around the rotation axis. Each fin acts as an independent segment that disrupts magnetic field lines individually, creating a cumulative effect that enhances position detection precision while maintaining reliable magnetic coupling through the distributed arrangement of segments.
Solution Approach 2:
The conductive fins are strategically positioned and dimensioned to create localized disruptions in the magnetic field at specific angular positions. This local modification of magnetic coupling properties allows precise angular-position sensing while the overall magnetic coupling remains stable through the distributed fin structure.
2Reliability
If larger targets are used to improve magnetic coupling, then sensing reliability increases, but target weight and device complexity increase
Solution Approach 1:
The target weight is reduced by segmenting it into thin radial fins rather than using a solid disk. The fins are spaced radially to provide sufficient magnetic coupling disruption for reliable sensing while minimizing material usage and overall target weight.
Solution Approach 2:
The target structure resembles a porous or latticed configuration with radial fins spaced apart, allowing magnetic field lines to pass through the gaps while still creating sufficient disruption for reliable position sensing. This reduces material density and weight compared to solid targets.
3Measurement precision
If conventional target shapes are used, then manufacturing is simple, but sinusoidal signal generation and sensitivity are reduced
Solution Approach 1:
The radial fins create an asymmetric pattern relative to the magnetic field distribution, which generates the desired sinusoidal signal characteristics. The asymmetric arrangement of conductive elements at specific radial positions and angles produces the necessary signal modulation for precise angular-position sensing.
Solution Approach 2:
The fins are arranged in a circular pattern around the rotation axis, creating a radially symmetric curved geometry that naturally generates sinusoidal signals as the target rotates. This curved, circular arrangement simplifies the mathematical relationship between physical position and signal output.
4Reliability
If more material is used in target design, then magnetic coupling is enhanced, but energy consumption and manufacturing cost increase
Solution Approach 1:
The target uses a porous-like structure with radial fins spaced to create optimal magnetic field disruption with minimal material. The gaps between fins allow magnetic field lines to pass through while still creating sufficient coupling for reliable sensing, reducing the energy required to maintain the magnetic field.
Solution Approach 2:
Material is extracted from a solid target design, retaining only the essential radial fin structures needed for magnetic coupling disruption. This extraction of non-essential material reduces weight and energy consumption while maintaining the core functionality of reliable position sensing.
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 proposed design results in more accurate angular-position sensing with reduced target size and weight, lower energy consumption, and improved sensitivity, enabling efficient rotor position sensing and broader manufacturing tolerances.
Implementation Method 1
If a coil of wire is placed in a changing magnetic field, a voltage will be induced at ends of the coil of wire. In a predictably changing magnetic field, the induced voltage will be predictable (based on factors including the area of the coil affected by the magnetic field and the degree of change of the magnetic field).
Implementation Method 2
The target body may include an inner circular ring and multiple fins formed with and extending radially from portions of the inner circular ring and equally radially spaced around the center axis, each fin formed as an arc band-shaped ring
Data Source
AI summary
Various examples include a target for inductive angular-position sensing and an inductive angular-position sensor including the same. The target has a target body comprising an inner circular ring around a center axis, and multiple fins formed with and extending radially from portions of the inner circular ring and equally radially spaced around the center axis. Respective ones of the multiple fins are formed as an arc band-shaped ring. In one or more examples, the respective ones of the multiple fins formed as the arc band-shaped ring provide a current path for an eddy current for the inductive angular-position sensing.