Domain-Wall Position Memory for Multi-Turn Absolute Measurement
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Solution Overview
Problem
Existing position measuring devices struggle to provide precise and reliable absolute position determination over multiple revolutions, especially during power outages, particularly in angular and linear measuring devices with large measurement lengths.
Innovation Solution
A position measuring device comprising a domain-wall memory with a domain-wall conductor and two magnets arranged orthogonally to the measurement direction, allowing for precise storage and retrieval of revolution information using a domain-wall conductor configured as a conducting trace on a substrate, with readout elements to determine magnetization status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a domain-wall memory is used to store revolution information, then reliability of position determination during power outages is improved, but device complexity increases
Solution Approach 1:
The memory function is segmented into discrete domain walls within the conductor, where each domain wall represents a stable magnetic state that can be written and read without power. This segmentation allows reliable storage of revolution information while keeping the overall device structure manageable.
Solution Approach 2:
The patent replaces traditional mechanical or electronic memory mechanisms with a magnetic domain-wall-based storage system. The domain walls in the conductor provide non-volatile memory functionality, eliminating the need for continuous power supply to maintain position information, thus improving reliability while avoiding complex power-dependent memory systems.
2Measurement precision
If multiple magnets are arranged end to end with varying distances, then measurement precision over multiple revolutions is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by creating specific distance variations between adjacent magnets only in the critical regions where domain wall formation occurs. The varying distances are localized to specific segments rather than requiring uniform precision across the entire magnet array, thus improving measurement precision while reducing overall manufacturing precision requirements.
Solution Approach 2:
The patent utilizes parameter changes by intentionally varying the distances between adjacent magnets to create specific magnetic field gradients. These parameter variations enable the formation of stable domain walls at defined positions, improving measurement precision while the variations are designed to be manufacturable within standard tolerances.
3Ease of operation
If magnets are magnetized orthogonally to the face with opposite directions, then the ability to move domain walls is improved, but device complexity increases
Solution Approach 1:
The patent applies asymmetry by magnetizing adjacent magnets in opposite directions with orthogonal orientation relative to the conductor face. This asymmetric magnetization pattern creates alternating magnetic field directions that naturally guide domain wall movement along the conductor, improving ease of operation while the pattern itself becomes the operational mechanism rather than requiring additional control elements.
Solution Approach 2:
The orthogonal magnetization arrangement with opposite directions creates a self-service system where the magnetic field pattern itself drives domain wall movement without requiring external actuation. The alternating magnetic fields automatically guide domain walls along the conductor in response to relative motion between the magnet assembly and conductor, eliminating the need for complex external control mechanisms.
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 reliable operational performance by storing and retrieving position information even during power outages, minimizing mechanical hysteresis effects, and allowing for accurate determination of angular or linear positions over multiple revolutions.
Implementation Method 1
a domain-wall memory (1.1) having a domain-wall conductor (1.11) running in a face (XY)
Implementation Method 2
The first and second magnets (2.1, 2.2) are arranged end to end in the measurement direction (x), magnetized such that their magnetization directions (D1, D2) run with an orthogonal directional component with respect to the face (XY)
Implementation Method 3
The magnets are arranged and configured such that a distance in the measurement direction (x) between the first magnet (2.1) and the second magnet (2.2) varies in size along a second direction (y)
Data Source
AI summary
A position measuring device including a first component group and a second component group. The first and second component groups are arranged so as to be movable relative to one another in a measurement direction. The first component group has a domain-wall memory including a domain-wall conductor running in a face. The second component group includes a first magnet and a second magnet. The first and second magnets are arranged end to end in the measurement direction, magnetized such that their magnetization directions run with an orthogonal directional component with respect to the face, and arranged such that they have opposite magnetization directions. The magnets are arranged and configured such that a distance in the measurement direction between the first magnet and the second magnet varies in size along a second direction that is oriented orthogonally to the measurement direction.