Incremental Length Measuring System with Doubled Absolute Track Pole Width
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Solution Overview
Problem
Magnetic tape length measuring systems face limitations in extending measuring range and accuracy due to minimum pole width constraints, leading to linearity deviations and positioning errors, especially with air gap influences and pseudo-random coded absolute tracks.
Innovation Solution
Doubling the pole width of the absolute track compared to the incremental track, along with additional tracks, to reduce linearity deviations and enhance positioning accuracy, allowing for error-free absolute position detection and improved switching properties of digital sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pole width of the absolute track is increased to reduce linearity deviations and improve positioning accuracy, then measurement precision improves, but the device complexity increases due to additional tracks and modified sensor arrangements
Solution Approach 1:
The measuring body is segmented into multiple tracks with different pole widths - an incremental track with pole width P1 and absolute tracks with pole width P2 = 2×P1. This segmentation allows each track to serve a specific function: the incremental track provides high-resolution positioning within a pole, while the wider absolute tracks provide linearity correction and absolute position detection, thereby improving overall measurement precision without requiring a single overly complex track structure
Solution Approach 2:
The solution transitions from a single-track design to a multi-dimensional track structure where additional absolute tracks are added with doubled pole width. This dimensional expansion (adding more tracks rather than enlarging a single track) enables simultaneous achievement of high positioning accuracy and reduced linearity deviations, as each track operates in its optimized width dimension
2Reliability
If the pole width of the absolute track is doubled to reduce the influence of air gap on switching properties, then reliability improves, but the manufacturing precision requirements increase due to tighter tolerances on track geometry
Solution Approach 1:
The pole width parameter of the absolute tracks is explicitly changed to P2 = 2×P1 (doubled compared to incremental track). This parameter change directly improves reliability by reducing air gap influence on switching properties, as the wider poles provide more stable magnetic fields that are less sensitive to air gap variations. The manufacturing precision challenge is managed by establishing clear geometric relationships between tracks rather than requiring absolute precision
3Measurement precision
If additional absolute tracks with further doubled pole width are added to improve positioning accuracy, then measurement precision improves, but the device complexity increases due to more tracks and sensors
Solution Approach 1:
The track structure implements a nested hierarchy where absolute tracks with pole width P2 = 2×P1 are integrated with the incremental track structure. Optional third tracks with P3 = 2×P2 can be added in the same manner. This nesting approach allows progressive enhancement of measurement precision - each additional track layer doubles the pole width and provides further accuracy improvement while maintaining a systematic, organized structure that manages complexity through hierarchical integration
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
Significantly reduces linearity deviations and positioning tolerances, enabling precise absolute position detection and increased sensor reliability, with the option to further enhance these effects by adding more tracks, applicable across various measuring principles.
Implementation Method 1
a magnetically encoded measuring body having an incremental track and at least one absolute track
Implementation Method 2
with GMR or AMR sensors, which measure the square of the magnetic flux density B2
Implementation Method 3
with GMR or AMR sensors
Implementation Method 4
with GMR or AMR sensors
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
In a length or position measuring system which has a dimension body (200, 205) that is at least locally essentially linear and at least one sensor (320, 325, 340) that can be moved relative to the dimension body (200, 205), wherein the dimension body (200, 205) comprises an incremental track (200) and at least one absolute track (205) and wherein the incremental track and the at least one absolute track (205) of the dimension body (200, 205) have poles (210, 215) with a pole width (220) specified in the longitudinal direction of the dimension body (200, 205), it is particularly provided that the pole width (225) of the at least one absolute track (205) is multiplied, in particular doubled, compared to the pole width (220) of the incremental track (200).