Linear Position Sensor Using Segmented Track Zones
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inductive position sensors face limitations in their useful measurement range due to edge effects, leading to reduced accuracy and increased manufacturing costs when trying to extend their measurement capabilities without losing existing advantages like contactless operation.
Innovation Solution
A contactless linear position sensor design featuring a track with a primary winding and two secondary windings organized in periodic geometries out of phase by a quarter-period, along with a target that covers the track in a strictly increasing manner, producing a sinusoidal signal to enhance measurement range without losing resolution or accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the measurement range is extended by adding more secondary windings, then the useful measurement length increases, but the device complexity and manufacturing cost increase
Solution Approach 1:
The measurement range is extended by dividing the track into multiple measurement zones, each zone utilizing a single secondary winding. The target's leading edge position relative to these zones enables measurement across the entire extended range without requiring multiple overlapping windings, thus extending measurement length while controlling device complexity
Solution Approach 2:
The patent transitions from measuring position within a single winding loop to measuring the target's leading edge position across multiple sequential zones along the track. This dimensional extension along the track length allows the useful measurement length to exceed the physical length of any single secondary winding
2Length of moving object
If the measurement range is extended, then the useful measurement length increases, but manufacturing precision requirements increase due to edge effects
Solution Approach 1:
The patent extracts and eliminates the problematic edge effects by ensuring the target's leading edge never simultaneously interacts with multiple winding loops. By measuring only the position where the leading edge crosses zone boundaries rather than measuring within overlapping loop regions, the harmful edge effects are removed while maintaining extended measurement capability
Solution Approach 2:
The patent converts the potential harm of edge effects into a beneficial measurement mechanism. The precise detection of the target's leading edge position as it transitions between zones becomes the measurement principle, transforming what could be a source of error into the fundamental measurement mechanism that enables extended range with maintained precision
3Length of moving object
If multiple secondary windings are used to extend range, then measurement length increases, but signal accuracy decreases due to transition phenomena
Solution Approach 1:
The patent introduces the target's leading edge as an intermediary measurement reference that sequentially interacts with each measurement zone. This leading edge serves as a clean transition marker between zones, providing unambiguous position information without the signal complexity that would arise from simultaneous interaction with multiple windings, thus maintaining signal accuracy across the extended range
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 increases the useful measurement length by 50 to 80% while maintaining accuracy and simplicity, reducing edge effects and manufacturing complexity.
Implementation Method 1
a primary winding adapted to induce an electrical current in a secondary winding
Implementation Method 2
the movement of the target modifies the coupling between the primary winding and the secondary winding, the position of which is deduced from the measured voltage at the terminals of the secondary winding
Data Source
AI summary
A device for measuring the position of a target includes a track, which includes a primary winding (513) supplied with an alternating current at high frequency, and a plurality of secondary windings (511, 512). The device measures the position of the leading edge (510) of the target (500) in a so-called longitudinal direction (5000) between a first position and a second position between which the target (500) completely covers the track (550). Surprisingly, this configuration enables a very significant increase in the useful measurement length of such a track (550).