Linear Position Sensor with Segmented Magnets for Accuracy
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Solution Overview
Problem
Conventional linear position sensors face challenges in achieving accurate detection across the entire stroke range, particularly in specific accuracy-required ranges or positions, due to unbalanced magnetic fields and fixed magnetic pole configurations.
Innovation Solution
The linear position sensor employs a detection object with a plurality of magnets spaced apart along the stroke direction, where adjacent magnetic pole surfaces have opposite poles, allowing for adjustable magnetic fields and improved detection accuracy through the use of a detector and signal processor that acquire and process sine and cosine signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic detection devices use a fixed magnetic pole configuration, then the structure is simple, but the detection accuracy is insufficient across the entire stroke range
Solution Approach 1:
The magnetic pole surface is divided into multiple magnetic poles arranged in a specific pattern. This segmentation allows different regions of the magnetic pole surface to contribute to detection accuracy at different positions along the stroke range, resolving the contradiction by making the magnetic field distribution more complex while maintaining overall structural simplicity
Solution Approach 2:
Different magnetic poles are positioned and configured to create locally optimized magnetic fields for specific detection regions. This allows the magnetic detection device to achieve high accuracy across the entire stroke range by having different parts of the magnetic pole structure serve different functional purposes
2Measurement precision
If magnets are spaced apart along the stroke direction with opposite poles, then detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The detection object is segmented into multiple magnets spaced apart along the stroke direction, with adjacent magnetic pole surfaces having opposite poles. This segmentation creates a magnetic field pattern that improves detection accuracy while the regular spacing maintains manufacturing simplicity
Solution Approach 2:
Instead of having all magnetic poles face the same direction, adjacent magnetic pole surfaces are configured with opposite poles. This inversion creates a alternating magnetic field pattern that enhances detection accuracy without requiring complex individual magnet configurations
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
This configuration enables enhanced detection accuracy across the entire stroke range and allows for selective improvement of accuracy in specific accuracy-required ranges or positions, effectively addressing the limitations of conventional sensors.
Implementation Method 1
a magnetic detection element and a plurality of magnetic members having magnetic pole surfaces facing the magnetic detection element
Data Source
AI summary
Magnets are arranged at intervals along a stroke direction with an interposed space. Magnetic pole surfaces of adjacent ones of the magnets have opposite poles. A detector is arranged with a gap in a gap direction against a magnetic pole surface of each of the magnets and acquires a sine signal and a cosine signal as detection signals of phases corresponding to the positions of the magnets, based on a change in a magnetic field received from the magnets according to movement of the detector relative to the detection object in the stroke direction. A signal processor acquires the sine signal and the cosine signal from the detector, generates, based on the sine signal and the cosine signal, an arctangent signal corresponding to a stroke amount of the detection object relative to the detector, and acquires the arctangent signal as a position signal.