Absolute Position Detection Device Using Segmented Sensor Groups
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Solution Overview
Problem
Existing absolute position detection devices require a large number of detection elements due to the limited interval at which they can be disposed without forming gaps, which is problematic for efficient position detection.
Innovation Solution
An absolute position detection device that includes a scale unit with alternated output pairs and a sensor unit with detection element groups disposed at specific intervals, allowing for the detection of positional correspondence information and the calculation of positional relationships between a mover and a stator with fewer detection elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If detection elements are disposed at a wide interval, then the number of detection elements is reduced, but the detection interval exceeds the magnetization pitch width causing ambiguous position detection
Solution Approach 1:
The patent divides the detection system into multiple detection element groups, where each group contains multiple detection elements disposed at a first interval. These groups are then disposed at a second interval along the movement path. This segmentation allows the system to use fewer groups while maintaining accurate position detection through the combined information from multiple elements within each group.
Solution Approach 2:
The patent transitions from one-dimensional linear arrangement of detection elements to a two-dimensional arrangement with detection element groups disposed at intervals along the movement path. Each group contains multiple elements at a first interval, creating a grid-like structure that enables accurate position detection with fewer groups by utilizing spatial distribution in multiple dimensions.
2Measurement precision
If detection elements are disposed densely along the entire movement path, then position detection accuracy is maintained, but the number of detection elements increases significantly
Solution Approach 1:
The patent segments the continuous array of detection elements into discrete groups distributed along the movement path. Each group contains multiple elements sufficient for accurate local position detection, while the intervals between groups reduce the total number of elements required compared to a continuous dense arrangement.
Solution Approach 2:
Each detection element group serves multiple functions: detecting position information for its local region, contributing to overall position calculation when combined with other groups, and providing redundancy for accurate measurement. This multi-functionality allows fewer groups to achieve the same overall detection accuracy as a dense continuous array.
3Quantity of substance
If the interval between detection elements exceeds the magnetization pitch width, then fewer detection elements are needed, but one magnetic field intensity corresponds to multiple stroke positions creating detection ambiguity
Solution Approach 1:
The patent segments detection elements into groups where each group contains multiple elements disposed at a first interval that does not exceed the magnetization pitch width. This ensures unambiguous local position detection within each group, while the groups themselves are disposed at a second interval that can span multiple magnetization pitches, reducing the total number of elements while maintaining reliability.
Solution Approach 2:
The computation unit processes position correspondence information from multiple detection elements within each group to calculate the position of the first member. By comparing and synthesizing information from multiple elements, the system resolves ambiguity that would exist with single-element detection, ensuring reliable position detection even when groups are spaced at larger intervals.
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 efficient detection of the positional relationship between a mover and a stator with fewer detection elements, enhancing the workability and reducing the complexity of the position detection system.
Implementation Method 1
detection elements that detect magnetic force are disposed at specific intervals along the movement path of the mover, and the detection elements measure the magnetic intensity of the position detecting member
Data Source
AI summary
An absolute position detection device includes: a scale unit having a first member and disposed on a mover or a stator; a sensor unit having detection elements disposed at a first interval to detect position correspondence information corresponding to the first member; and a computation unit that: detects a distortion boundary position of output based on a comparison result between the position correspondence information by first and second detection elements; based on element coordinates of either the first or second detection element, element coordinates of a third detection element, the first interval, a length of the output pairs, and the position correspondence information by the third detection element, calculates a position of the third detection element to an end position of the first member; and calculates a positional relationship between the mover and the stator based on the calculated position and a length of the first member.