Inductive Encoder Receiver Line Spacing for Cross-Coupling Reduction
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Solution Overview
Problem
Inductive position encoders face challenges in achieving a combination of high signal strength, compact size, high resolution, cost-effectiveness, robustness to misalignment and contamination, and reduced signal contamination due to cross-coupling issues between multiple pattern tracks of different wavelengths.
Innovation Solution
The use of a multi-layer printed circuit board with field generating coils and sensing elements arranged in a specific configuration, where spatial phase crossover segments of one pattern track are positioned at integer multiples of the wavelength of another pattern track to reduce cross-coupling, thereby improving encoder performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pattern tracks with different wavelengths are used to achieve high resolution and compact size, then measurement precision and device size are improved, but signal contamination due to cross-coupling between tracks increases
Solution Approach 1:
The patent converts the harmful cross-coupling signal contamination into a beneficial effect by deliberately designing receiver lines to cross over adjacent pattern tracks at specific locations. The crossover segments are positioned to overlap with pattern tracks at integer multiples of their wavelengths, which causes the induced signals from adjacent tracks to be in phase and reinforce each other constructively, thereby converting the previously harmful cross-coupling into a useful signal enhancement mechanism
Solution Approach 2:
The patent changes the spatial parameter of receiver line positioning by specifying that crossover segments must be located at positions corresponding to integer multiples of the adjacent pattern track wavelength (λ2, λ3, etc.). This parameter change ensures that the magnetic flux induction from adjacent tracks occurs at相位 points that produce constructive interference, transforming the cross-coupling from harmful to beneficial
2Reliability
If receiver lines are positioned to reduce cross-coupling, then signal purity is improved, but device complexity increases due to precise positioning requirements
Solution Approach 1:
The patent simplifies the positioning requirement by changing the parameter specification from arbitrary precise positioning to a standardized grid-based system where crossover segments are placed at integer multiples of pattern track wavelengths. This parameter change transforms a complex continuous positioning problem into a discrete, easily manufacturable solution that maintains signal purity while reducing fabrication complexity
3Power
If crossover segments overlap with adjacent pattern tracks, then signal strength is improved through constructive interference, but signal contamination from other tracks increases
Solution Approach 1:
The patent converts the potentially harmful signal contamination from adjacent pattern tracks into a beneficial reinforcement mechanism. By positioning crossover segments at integer multiples of adjacent track wavelengths, the induced signals from overlapping tracks arrive in phase and constructively interfere, transforming what would normally be contaminating signals into useful signal strength enhancement
Solution Approach 2:
The patent utilizes the periodic nature of the pattern tracks by positioning crossover segments at integer multiples of their wavelengths. This periodic positioning ensures that the magnetic flux induction from adjacent tracks consistently occurs at corresponding相位 points, producing constructive interference and reinforcing the detector signal through periodic, synchronized action
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
This configuration significantly reduces signal contamination and enhances the overall performance of the encoder by minimizing common mode errors and improving signal accuracy and robustness.
Implementation Method 1
generates a first-track changing first magnetic flux in the first interior area in response to a coil drive signal
Implementation Method 2
configured to provide detector signals which respond to a local effect on the first-track changing magnetic flux
Data Source
AI summary
An electronic position encoder includes a scale comprising a first pattern track of signal modulating elements (SME) periodically arranged at a wavelength λ1 and a second pattern track of SME periodically arranged at a wavelength λ2, a detector, and a signal processing configuration. The detector includes a field generating coil configuration, a first set of sensing elements configured to provide detector signals based on the first pattern track, and a second set of sensing elements configured to provide detector signals based on the second pattern track. The first set of sensing elements include a first spatial phase subset of sensing elements and a second spatial phase subset of sensing elements that are connected to the signal processing configuration via at least a first pair and a second pair of connection lines that include respective crossover segments that extend across or overlap the second pattern track. The respective crossover segments are positioned at locations spaced apart along a measuring axis direction by a distance N*λ2, where N is an integer.