Inductive Coil Position Sensor for Gap-Tolerant Contactless Detection
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Solution Overview
Problem
Contactless position sensors face challenges in maintaining sensing range and accuracy due to physical gaps and misalignment issues, particularly when the target structure is at varying distances or covered in dirt/grease, and existing solutions like magnetic sensors require precise housings and mechanical assembly.
Innovation Solution
A contactless sensor system utilizing a set of inductively coupled coils to detect changes in electromagnetic near-field variations, allowing for the detection of a target structure's presence and relative position, even at greater distances, by measuring voltage changes across the coils, which are indicative of the target's position within the near-field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a physical gap is maintained between the sensor and target structure to eliminate contacts, then electrical noise and disturbances are reduced, but the sensing range and accuracy deteriorate
Solution Approach 1:
The patent combines multiple coils (first coil and second coil) into a single sensor assembly, where the coils work together to generate and detect electromagnetic fields. This merging allows the sensor to maintain a physical gap from the target structure while still achieving accurate position detection through the cooperative electromagnetic field interaction of multiple coils.
Solution Approach 2:
The patent uses electromagnetic fields as an intermediary between the sensor and target structure. Instead of direct physical contact, the electromagnetic field serves as the medium for transmitting position information, allowing the sensor to operate at a distance while maintaining measurement capability. The field acts as a mediator that bridges the physical gap between sensor and target.
2Reliability
If magnetic sensors are used to detect target position, then contactless detection is achieved, but precision housing and mechanical assembly are required to avoid misalignment errors
Solution Approach 1:
The patent segments the sensor into multiple independent coils (first coil and second coil) that can be positioned relative to each other in a fixed configuration. This segmentation allows the sensor to detect target position through the relative positioning of multiple field sources, reducing the need for ultra-precise single-point alignment and distributing the alignment requirements across multiple elements.
Solution Approach 2:
The coil assembly serves multiple functions: generating the electromagnetic field for detection, serving as the sensing element itself, and providing a compact integrated structure. This multi-functionality eliminates the need for separate precision housing components that would be required in traditional magnetic sensor arrangements, as the coils themselves perform both field generation and detection roles.
3Length of stationary object
If the gap between sensor and target structure increases, then the sensing range is extended, but the signal strength and detection accuracy decrease
Solution Approach 1:
The patent merges multiple coils into a single sensor unit, where the combined electromagnetic field of the first and second coils provides stronger field penetration and signal strength at greater distances. The cooperative effect of multiple coils maintains detection capability even when the sensor operates further from the target structure, effectively extending the usable sensing range without sacrificing signal quality.
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 system effectively increases the sensing range and reduces sensitivity to distance variations, providing accurate detection of the target structure's position with improved signal strength and reduced noise susceptibility, even in challenging environmental conditions.
Implementation Method 1
a first coil (110), e.g., a sensing coil, including an electromagnetic structure for generating an electromagnetic near-field upon receiving energy
Implementation Method 2
the electromagnetic near-field provides at least a portion of the energy to the second coil (120A) through inductive coupling, inducing a current to pass through the set of coils
Implementation Method 3
a presence of an external electromagnetic structure moving within the electromagnetic near-field disturbs the magnetic field and thus can be detected based on the changes in the measurements of the voltage
Data Source
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AI summary
A sensor including a set of coils. The set of coils include a first coil and a second coil, wherein the first coil upon receiving energy, generates an electromagnetic near-field, such that the electromagnetic near-field provides at least a portion of the energy to the second coil through inductive coupling, inducing a current to pass through the set of coils. Further, a detector for measuring a voltage across at least one of the first coil or the second coil, wherein the detector includes a voltmeter. Finally, a processor for detecting a presence of a target structure in proximity to the set of coils upon detecting a change in a value of the voltage, wherein the target structure is an electromagnetic structure moving at a distance from the set of coils.