Magnetic Absolute Position Sensing via Primary Harmonic Detection
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Solution Overview
Problem
Existing rotary encoder systems, particularly those using magnetic materials, are limited in detecting the absolute position of rotating bodies, such as vehicle wheels, due to their complex structure and inability to accurately measure absolute positions, which restricts their application in various fields.
Innovation Solution
A magnetic absolute position detection device and method utilizing magnets with n pole pairs and n+1 magnetic materials arranged around a rotating body, coupled with Hall sensors to detect primary harmonics and measure absolute positions, allowing for a simpler and more efficient detection mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing magnetic encoder systems are used to detect absolute position of rotating bodies, then detection capability is provided, but the structure becomes complex and application range is restricted
Solution Approach 1:
The detection system is segmented into distinct functional components: magnets with n pole pairs mounted on the rotating body, n+1 magnetic materials arranged in a specific pattern, and Hall sensors positioned to detect magnetic field changes. This segmentation allows each component to perform its specific function efficiently while simplifying the overall structure compared to traditional encoders.
Solution Approach 2:
The system utilizes changes in magnetic field parameters (strength and direction) as the magnetic materials rotate past the Hall sensors. By detecting these parameter changes and processing the signal to identify primary harmonics, the system achieves absolute position detection without requiring complex mechanical structures.
2Measurement precision
If traditional encoder systems are used, then position detection is enabled, but the structure is complex and economical efficiency is reduced
Solution Approach 1:
The patent replaces complex mechanical encoder structures with a magnetic field-based detection system. Instead of using mechanical gratings, read heads, and complex signal processing mechanisms, the invention uses magnets, magnetic materials, and Hall sensors to detect position through magnetic field interactions, significantly simplifying manufacturing.
Solution Approach 2:
The system detects position by monitoring changes in magnetic field parameters rather than relying on complex mechanical structures. The Hall sensors measure magnetic field strength variations as magnetic materials rotate, and the controller processes these parameter changes to determine absolute position, enabling easier manufacturing while maintaining detection accuracy.
3Ease of manufacture
If magnetic materials with simple structure are used, then ease of manufacture is improved, but detection accuracy may be compromised
Solution Approach 1:
The system uses n+1 magnetic materials with n pole pairs, creating an asymmetric configuration where the number of magnetic materials exceeds the number of pole pairs by one. This asymmetric arrangement generates specific magnetic field patterns that produce detectable primary harmonics, enabling accurate absolute position detection while maintaining simple magnetic material structures.
Solution Approach 2:
The controller receives feedback signals from the Hall sensors and processes them to identify primary harmonics corresponding to absolute position. This feedback mechanism allows the system to achieve high detection accuracy by analyzing the magnetic field signal patterns generated by the simple magnetic material structure, rather than requiring complex materials.
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
Enables accurate detection of absolute positions of rotating bodies using primary harmonics, improving the economical efficiency and expanding the application range of the detection device by simplifying the structure and enhancing measurement accuracy.
Implementation Method 1
a first Hall sensor spaced apart from the magnet by a predetermined interval, installed to allow the magnetic material to rotate to a space between the first Hall sensor and the magnet and outputting a signal based on the magnets when the magnetic material approaches the first Hall sensor
Data Source
AI summary
This application relates to an absolute position detection device and detection method of a rotating body using a magnetic material. The device may include magnets coupled to a rotating body and configured to rotate together and having n pole pairs, wherein n is a natural number and (n+1) magnetic materials arranged adjacent to the magnets, spaced apart from each other by a predetermined interval, and configured to rotate together with the rotating body. The device may also include a first Hall sensor spaced apart from the magnets, installed to allow the magnetic materials to rotate in a space between the first Hall sensor and the magnets and configured to output a first signal based on the magnets when the magnetic materials approach the first Hall sensor. The device may further include a controller configured to measure an absolute position of the rotating body using the first signal.