Contactless Position Sensor with Variable Magnetization for High Precision
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Solution Overview
Problem
Existing magnetic position sensors lack sufficient precision and are cumbersome or expensive, limiting their use in high-precision applications.
Innovation Solution
A contactless position sensor using a permanent magnet with continuously variable magnetization and multiple detection elements to measure magnetic field components, combining quasi-periodic patterns for precise position determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional magnetic position sensors are used, then the device structure is simple, but the measurement precision is insufficient (>1° mechanical)
Solution Approach 1:
The sensor system is divided into two functional parts: a coarse measurement system using a 360° Hall effect sensor for overall position detection, and a fine measurement system using a magneto-resistive sensor for precise local measurement. This segmentation allows achieving high precision without requiring a completely complex sensor design.
Solution Approach 2:
The patent combines two different sensor technologies (Hall effect sensor and magneto-resistive sensor) into a single integrated measurement system. The Hall sensor provides coarse positioning while the magneto-resistive sensor provides fine positioning, and their outputs are combined through a processing circuit to achieve overall high-precision measurement.
2Measurement precision
If resolver sensors are used, then the measurement precision is very important, but the device becomes bulky and expensive
Solution Approach 1:
The patent extracts only the essential function of resolvers (precise angular position measurement) and implements it using a simplified magnetic field detection approach with Hall and magneto-resistive sensors, eliminating the need for complex resolver structures while maintaining measurement precision.
Solution Approach 2:
The patent uses inexpensive Hall effect sensors and magneto-resistive sensors instead of expensive resolver sensors, achieving cost-effective high-precision measurement suitable for mass production in automotive and industrial applications.
3Measurement precision
If encoder sensors are used, then the measurement precision is very high, but the device complexity and assembly difficulty increase
Solution Approach 1:
The patent replaces complex mechanical encoder structures with a magnetic field-based detection system using Hall and magneto-resistive sensors. This substitution eliminates mechanical complexity while maintaining high measurement precision and simplifying assembly.
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
Achieves high-precision angular or linear position measurement with accuracy below 0.5° and cost-effectiveness, suitable for various applications without complex assembly.
Implementation Method 1
a permanent magnet (or magneto-coding element) generating a magnetic field
Implementation Method 2
A first sensor solution of the '360° Hall effect sensor' type
Data Source
AI summary
A contactless position sensor comprises a permanent magnet generating a magnetic field and at least one element for detecting magnetic fields (or magneto-sensitive element) in at least two directions. The permanent magnet is capable of moving in a movement direction and has a continuously variable magnetization in the movement direction. The variation in the magnetization has, along the different field components, a shape corresponding to a combination of at least two different quasi-periodic contributions. The sensor further comprises a computer for combining the values of these field components and for determining a precise value of the position.