Domain Wall Position Sensing With Opposed Magnets for Low Hysteresis
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Solution Overview
Problem
Existing position measuring devices, particularly multi-turn angle and length measuring devices, face challenges in maintaining precise and reliable operation, especially during power outages, and require efficient non-volatile storage of position information.
Innovation Solution
A position measuring device with a domain wall memory system comprising a first and second component group, where the second group includes magnets with orthogonal magnetization directions and varying distances, and a domain wall conductor for storing information through domain wall shifts, allowing for reliable operation without auxiliary power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single permanently diametrically magnetized permanent magnet is used to move domain walls, then the device structure is simple, but the position measurement precision and reliability deteriorate due to mechanical hysteresis effects
Solution Approach 1:
The single permanent magnet is divided into two separate permanent magnets with opposite magnetization directions. This segmentation allows the magnets to be positioned on opposite sides of the domain wall conductor, creating a more balanced magnetic field configuration that reduces mechanical hysteresis effects and improves measurement precision while maintaining structural simplicity.
Solution Approach 2:
The two permanent magnets are positioned asymmetrically relative to the domain wall conductor, with each magnet having its own optimized distance to the conductor. This asymmetric positioning allows for fine-tuning of the magnetic field distribution, minimizing hysteresis effects and enhancing position measurement accuracy.
2Device complexity
If the distance between magnets is uniform, then the magnetic field distribution is simple, but the domain wall control precision deteriorates
Solution Approach 1:
Each permanent magnet is positioned at a specific optimized distance from the domain wall conductor, creating locally optimized magnetic field conditions. The first magnet is positioned at a first distance and the second magnet at a second distance, allowing each region to have the ideal magnetic field strength for precise domain wall control and manipulation.
3Speed
If volatile memory is used to store position information, then the device operates quickly, but the reliability deteriorates during power outages
Solution Approach 1:
The patent replaces electronic volatile memory with a domain wall-based magnetic memory system. Position information is stored as domain wall positions in the domain wall conductor, which maintains data without power. This substitution of magnetic domain structures for electronic memory cells provides non-volatile storage while maintaining fast read/write capabilities through magnetic field manipulation.
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 precise and reliable position measurement over multiple revolutions or displacements, with the ability to store and retrieve position information even during power failures, minimizing mechanical hysteresis effects.
Implementation Method 1
The first and second magnets are arranged and designed such that the distance between them, relative to the measurement direction, differs along a second direction
Implementation Method 2
a domain wall conductor extending in a plane... storing position information through domain wall shifts
Implementation Method 3
enables precise and reliable position measurement over multiple revolutions or displacements, with the ability to store and retrieve position information even during power failures
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a position measuring device comprising a first component group (1; 1') and a second component group (2; 2') which are arranged to be movable relative to each other in a measuring direction (x). The first component group (1; 1') has a domain wall memory (1.1; 1.1') which includes a domain wall conductor (1.11; 1.11') extending in a surface (XY). The second component group (2; 2') comprises a first magnet (2.1; 2.1') and a second magnet (2.2; 2.2') wherein the magnets (2.1, 2.2; 2.1', 2.2') are arranged in series in the measuring direction (x) and are magnetized such that their magnetization directions (D1, D2; D1', D2') have a directional component orthogonal to the surface (XY). The magnets (2.1, 2.2; 2.1', 2.2') are arranged such that they have opposite magnetization directions (D1, D2; D1', D2'). Furthermore, the magnets (2.1, 2.2; 2.1', 2.2') are arranged such that they have opposite magnetization directions (D1, D2; D1', D2').2') arranged and designed such that the distance (u, U; u', U') in the measuring direction (x) between the first magnet (2.1; 2.1') and the second magnet (2.2; 2.2') is of different sizes along a second direction (y; y') which is oriented orthogonally to the measuring direction (x). (Figure 3).