Electromagnetic Resonant Coil Sensing for High-Precision Weight Detection

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Solution Overview

Problem

Existing gas/liquid volume and weight sensing technologies suffer from limited sensitivity and accuracy due to their linear measurement mechanisms, which are affected by thermal expansion and density variations, making them unsuitable for high-precision detection in intelligent equipment.

Innovation Solution

An electromagnetic coupling sensing device utilizing a frequency generation module, first and second resonant modules, and an echo acquisition and processing module, where a coil with a ferrite core deforms under weight load, altering the intrinsic frequency and enhancing sensitivity through critical coupling near-field effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional volume sensors or weight sensors are used for measurement, then the measurement function is achieved, but the sensitivity is limited by the linear device mechanism

Engineering Contradiction:
Improvemeasurement sensitivityVSAvoiddevice mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical linear measurement mechanisms with an electromagnetic resonance-based measurement system. The coil spring is transformed into an inductive coil that forms part of a resonant circuit, where mechanical deformation under weight is converted into changes in inductance and resonance frequency. This substitution eliminates the limitations of linear mechanical sensors and enables higher sensitivity through resonance amplification effects.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from direct mechanical displacement or force to resonance frequency and inductance variations. By measuring the shift in resonance frequency caused by weight-induced deformation of the coil spring, the system achieves enhanced sensitivity. The resonant circuit parameters (inductance, capacitance, resistance) are optimized to maximize the frequency shift response to small weight changes.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If volume measurement or weight measurement is used for liquids and gases, then the measurement function is achieved, but the accuracy is affected by thermal expansion and density variations

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidenvironmental interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces thermal and density-dependent volume/weight measurement with an electromagnetic resonance measurement system. The coil spring's resonance frequency depends on its mechanical properties (mass, stiffness) rather than thermal expansion or fluid density, making the measurement immune to environmental temperature and density variations. This substitution fundamentally eliminates the harmful effects of thermal expansion and density changes on measurement accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If a coil spring is used to measure weight through inductance change, then the measurement function is achieved, but the sensitivity is insufficient without resonant circuit enhancement

Engineering Contradiction:
Improveweight measurement sensitivityVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent utilizes mechanical vibration in the form of electromagnetic resonance to amplify the measurement signal. The coil spring is excited to vibrate at its resonant frequency, and the resonance amplifies the inductance changes caused by small weight variations. This vibration-based approach enhances sensitivity without requiring excessive power, as the system operates at natural resonant frequencies where minimal energy input produces maximum response.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent exploits the phase transition-like behavior in resonant circuits, where the system transitions from non-resonant to resonant states. At resonance, the circuit exhibits sharp changes in impedance and current amplitude, creating a highly sensitive detection point. By operating at this critical resonance point, the system achieves maximum sensitivity with minimal power consumption, as the resonant condition naturally amplifies small perturbations.

Inventive Principle:
Principle #36Phase transitions

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 device achieves improved measurement accuracy and sensitivity by leveraging critical coupling near-field effects, ensuring high-precision detection of gas/liquid levels despite environmental variations.

Implementation Method 1

The coil is capable of carrying a weight to be measured to deform such that an intrinsic frequency of the electromagnetic coupling sensing device changes

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The second resonant module couples with the first resonant module through a coupling capacitance to generate a secondary resonant signal based on the primary resonance signal

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Implementation Method 3

The first resonant module generates a primary resonant signal based on the frequency setting signal

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4431892B1Electromagnetic coupling sensing device, signal measurement method, and related electronic device
Publication Date: 2026.01.28 SMYZE INTELLIGENCE TECHNOLOGY (SHANGHAI) CO LTD
  • EP4431892B1 patent drawingFigure 1~2
  • EP4431892B1 patent drawingFigure 3~4
  • EP4431892B1 patent drawingFigure 5~6

AI summary

An electromagnetic coupling sensing device includes a frequency generation module, a first resonant module, a second resonant module, and an echo acquisition and processing module. The first resonant module generates a primary resonant signal based on the frequency setting signal generated by the frequency generation module. The second resonant module couples with the first resonant module through a coupling capacitance to generate a secondary resonant signal based on the primary resonance signal. The second resonant module includes a coil. A ferrite is provided in the coil and a height of the coil is higher than the ferrite. The coil is capable of carrying a weight to be measured to deform such that an intrinsic frequency of the electromagnetic coupling sensing device changes. The echo acquisition and processing module collects the secondary resonant signal and outputs a voltage signal changing according to the intrinsic frequency.