Dual-Sensor Piston Position Detection Against External Magnetic Fields

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Solution Overview

Problem

Existing piston position detection devices suffer from false detections due to external magnetic fields, leading to abnormal operations in programmable logic controllers, and face challenges in miniaturization and cost reduction.

Innovation Solution

A piston position detection device that employs a first sensor to detect the magnetic field generated by a magnetic material on the piston and a second sensor to detect external magnetic fields, using an algorithm to ignore false signals, thereby avoiding physical structure changes and enabling miniaturization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a magnetic field blocking method using a metal material with high permeability is used, then false detection of the magnetic sensor is prevented, but the physical structure becomes large and complicated

Engineering Contradiction:

Improvefalse detection preventionVSAvoidphysical structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and removes the magnetic field blocking metal material from the sensor structure. Instead of using physical blocking, the system uses a detection algorithm that identifies and ignores signals caused by external magnetic fields, thereby eliminating the need for complex magnetic shielding structures while maintaining false detection prevention

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical/physical magnetic field blocking system with an algorithmic/software-based detection system. The control unit uses timing information and signal characteristics to distinguish between valid piston position signals and false external magnetic field signals, substituting physical structure with intelligent processing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a blocking metal is used to block the external magnetic field, then false detection is avoided, but the manufacturing cost increases

Engineering Contradiction:

Improvefalse detection preventionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention replaces expensive high-permeability alloy blocking materials with a cost-effective algorithmic approach implemented in the control unit. The software-based false detection prevention eliminates the need for costly magnetic shielding materials while maintaining the same reliability function

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention substitutes the expensive physical magnetic field blocking system with an economical algorithmic solution. The control unit processes sensor signals using timing and signal characteristic analysis, replacing costly materials with intelligent software processing that achieves the same false detection prevention at lower manufacturing cost

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a blocking metal is used to block the external magnetic field, then false detection is prevented, but wireless signal transmission is blocked requiring cable connections

Engineering Contradiction:

Improvefalse detection preventionVSAvoidwireless signal transmission

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The invention extracts and removes the magnetic field blocking metal material that was obstructing wireless signals. By replacing physical blocking with algorithmic false detection prevention, the system eliminates the barrier to wireless communication while maintaining sensor functionality and false detection avoidance

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the physical magnetic field blocking structure with an algorithmic solution that does not interfere with electromagnetic wave propagation. This substitution enables wireless signal transmission while maintaining false detection prevention, as the software-based approach does not physically obstruct any signals

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 effectively avoids false detections caused by external magnetic fields, allows for miniaturization of the device, reduces manufacturing costs, and enables wireless transmission of piston position data, simplifying machine handling and reducing fire risks.

Implementation Method 1

a first sensor which detects a magnetic field generated by the magnetic material to detect a position of a piston

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

a second sensor which detects an external magnetic field to prevent a false detection of the first sensor

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentUS12338844B2Piston position detection device

Publication Date: 2025.06.24 ASIANA IDT INC

AI summary

The present invention provides a device for detecting the position of a piston, which includes a magnetic substance and is arranged so as to be movable inside a cylinder, the piston position detection device comprising: a first sensor for detecting the position of the piston by sensing a magnetic field generated by the magnetic substance; a second sensor for preventing false detection of the first sensor by sensing, before the first sensor, an external magnetic field; and a housing, which is mounted on the outer circumferential surface of the cylinder and accommodates the first sensor and the second sensor therein.