Tilt-Tolerant Linear Displacement Sensor Design
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Solution Overview
Problem
Eddy current-based linear displacement sensors face challenges with tolerance robustness and space requirements, particularly due to tilting and changes in distance, which affect measurement accuracy and require multiple coils and conductive traces.
Innovation Solution
A linear displacement sensor design featuring an induction element with a measurement track and a correction track on opposite sides, utilizing eddy current principles to determine position, with a correction coil to compensate for tilting and displacement, allowing for a compact structure and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple measuring coils and conductive traces are used to achieve tolerance robustness, then measurement accuracy under tilting and displacement improves, but device complexity and installation space increase
Solution Approach 1:
The sensor is divided into two functionally independent segments: a measurement sensor element with measurement coil and track for detecting position, and a correction sensor element with correction coil and track for compensating tilting and displacement. This segmentation allows each element to be optimized for its specific function while working together to achieve tolerance robustness without requiring multiple coils and traces in a single complex assembly
Solution Approach 2:
The correction sensor element acts as an intermediary that measures tilting and displacement effects and provides correction data that is used to compensate the measurement from the measurement sensor element. This intermediary approach allows the system to handle tolerance issues without directly complicating the main measurement path
2Measurement precision
If multiple measuring coils and conductive traces are used to achieve tolerance robustness, then measurement accuracy under tilting and displacement improves, but installation space increases
Solution Approach 1:
The measurement track and correction track are arranged on opposite sides of the induction element, utilizing the third dimension (depth/spacing) rather than expanding in the planar dimensions. This spatial arrangement allows both tracks to coexist without increasing the overall footprint of the sensor, achieving tolerance compensation within a compact volume
Solution Approach 2:
By separating measurement and correction functions into distinct sensor elements with their own coils and tracks, the design achieves tolerance robustness through functional segmentation rather than through spatial expansion with multiple overlapping coils and traces in a single element
3Measurement precision
If eddy current principle is used for position detection, then measurement capability is achieved, but sensitivity to distance changes and tilting increases
Solution Approach 1:
The correction sensor element provides feedback information about tilting and displacement conditions, which is then used to compensate the measurement from the measurement sensor element. This feedback mechanism allows the system to maintain measurement reliability despite tolerance variations and environmental conditions that affect the eddy current effect
Solution Approach 2:
The correction sensor element serves as an intermediary that measures the adverse effects (tilting and displacement) and provides correction data to compensate the main measurement, thereby reducing the sensitivity to these factors while preserving the position detection capability
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 solution provides a tolerance-robust and space-efficient linear displacement sensor with enhanced measurement accuracy, capable of handling tilting and displacement, and is resistant to electromagnetic interference, enabling cost-effective construction and precise position determination.
Implementation Method 1
The measuring coil induces an eddy current in the conductive track, which leads to a change in the inductance of the measuring coil
Implementation Method 2
The measuring coil induces an eddy current in the conductive track, which leads to a change in the inductance of the measuring coil
Implementation Method 3
the correction coil and also works with the eddy current principle
Implementation Method 4
the correction coil and also works with the eddy current principle
Data Source
Figure 1A~1C
Figure 2
Figure 3A~3C
AI summary
The invention relates to a linear displacement sensor (10) comprising an induction element (12), which has on a first side an electrically conductive measuring track (16) running along a measurement path (M); and a measuring sensor element (20), which is arranged over the first side of the induction element (12) and is movable relative to the induction element (12) along the measurement path (M), wherein the measuring sensor element (20) comprises a measuring coil (22), which is arranged over the measuring track (16) and wherein an overlap between the measuring coil (22) and the measuring track (16) changes along the measurement path in such a manner that an induction of the measuring coil (22) is dependent on a position (y) of the measuring coil (22) on the measurement path (M); wherein a correction sensor element (21) is connected rigidly to the measuring sensor element (20) and is arranged over a second side of the induction element (12); wherein the induction element (12) has on the second side at least one electrically conductive correction track (18) running along the measurement path (M); and the correction sensor element (21) has at least one correction coil (24), the overlap of which with the correction track (18) is constant along the measurement path (M).