Position Measurement with Domain Wall Memory for Absolute Encoding
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Solution Overview
Problem
Existing position measuring devices, such as angle and length measuring devices, face challenges in achieving a compact design while ensuring precise and non-volatile storage of rotation or position information over multiple revolutions, particularly in applications requiring absolute position determination over large measuring lengths.
Innovation Solution
A position measuring device with a domain wall memory is designed, comprising a first and second component group with a domain wall conductor and a scale, where the scale is scanned by a detector unit to determine relative position, utilizing a domain wall conductor configured as a conductor track or nanowire to store information through magnetized regions separated by domain walls, and readout elements to detect magnetization states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a domain wall memory is integrated into the position measuring device to enable non-volatile storage of position information, then the reliability and data retention capability are improved, but the device complexity increases due to additional components such as domain wall conductors, magnets, and readout elements
Solution Approach 1:
The patent combines the domain wall memory functionality with the existing position measurement system by integrating the domain wall conductor, magnets, and readout elements into the component groups already present in the measuring device. This merging approach allows non-volatile storage capability to be added while sharing existing structural elements, thereby reducing the overall complexity increase that would result from completely separate memory system integration.
Solution Approach 2:
The domain wall conductor serves multiple functions: it acts as both the memory storage medium and an integral part of the position sensing system. The magnets serve dual purposes by both generating the magnetic field for domain wall manipulation and providing the magnetic field necessary for position detection. This multi-functionality reduces the total number of separate components needed, thereby managing device complexity while achieving reliable non-volatile storage.
2Measurement precision
If the domain wall conductor is placed closer to the scale to improve measurement precision, then the measurement precision is improved, but the first distance becomes smaller requiring tighter manufacturing tolerances
Solution Approach 1:
The patent applies local quality by positioning the domain wall conductor at a specific optimized distance from the scale in the region where position measurement occurs. This localized optimization allows the conductor to be placed close enough to the scale to achieve high measurement precision through strong magnetic field interaction, while the housing and mounting structures provide stable reference frames that minimize the impact of manufacturing tolerances on the critical distance.
Solution Approach 2:
The housing structure is designed and pre-assembled with integrated mounting features for the domain wall conductor, scale, and magnets before final positioning. This preliminary structuring establishes stable reference frames and pre-defined mounting locations that reduce sensitivity to manufacturing tolerances during final assembly, allowing the domain wall conductor to be positioned optimally close to the scale without requiring extremely tight tolerances across all components.
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
The device achieves a compact and precise design capable of storing and determining position information non-volatilely, allowing for accurate absolute position measurement over multiple revolutions without auxiliary power, even in power failures.
Implementation Method 1
The at least one magnet is designed and arranged such that it can generate a displacement of at least one domain wall in the domain wall conductor when the magnet passes by
Implementation Method 2
To determine the relative position between the scale and the detector unit in the measuring direction, the scale can be scanned by the detector unit
Data Source
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AI summary
The invention relates to a position measuring device comprising a first component group (1; 1') and a second component group (2), wherein the component groups (1; 1', 2) are arranged to be movable relative to each other in a measuring direction (x). The first component group (1; 1') has a first printed circuit board (1.1) comprising a detector unit (1.11, 1.12, 1.13, 1.14) and a second printed circuit board (1.2) comprising a domain wall conductor (1.211). The first printed circuit board (1.1) is arranged offset from the second printed circuit board (1.2) in the measuring direction (x). The second component group (2) comprises a scale (2.1, 2.2) and a magnet (2.3, 2.4). The scale (2.1, 2.2) is arranged between the magnet (2.3, 2.4) and the second printed circuit board (1.2). The magnet (2.3, 2.4) is arranged such that it can cause a displacement of a domain wall in the domain wall conductor (1.211) when the magnet (2.3, 2.4) passes by. (Figure 1)