Piezoelectric Vibrating Wire Sensor for Low Power Shock-Resistant Measurement

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Solution Overview

Problem

Vibrating string sensors face high power consumption and sensitivity issues due to magnetic elements, as well as challenges in shock-proof attachment and drift over time.

Innovation Solution

A vibrating string sensor with a piezoelectric activation layer reduces power consumption and eliminates magnetic elements, featuring a compact structure and bimetal spring-like deformation for vibration generation, using an excitation layer with different lengths depending on activation state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If magnetic field generating elements are used to excite the vibrating wire, then the wire can be set into vibration at its natural frequency, but power consumption increases and the sensor becomes sensitive to shock and rough handling

Engineering Contradiction:
Improvepower consumptionVSAvoidsensitivity to shock and handling
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent removes the magnetic field generating elements (electromagnets or permanent magnets) from the sensor system entirely. Instead, it uses a piezoelectric excitation element that directly contacts and vibrates the wire through mechanical coupling, eliminating the magnetic components that caused power consumption and reliability issues.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the electromagnetic excitation system with a piezoelectric mechanical system. The piezoelectric element converts electrical signals directly into mechanical vibrations that are transmitted to the wire, substituting the magnetic field-based excitation mechanism with a direct mechanical coupling approach.

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

2Device complexity

If magnetic field generating elements are used to excite the vibrating wire, then vibration can be generated, but the device complexity and shock-proof mounting requirements increase

Engineering Contradiction:
Improvestructural complexityVSAvoidshock-proof mounting
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The patent merges the excitation element directly with the vibrating wire through mechanical contact. The piezoelectric excitation element is positioned to directly touch and vibrate the wire, combining what were previously separate components (magnetic field generator and wire) into a more integrated, simpler structure that eliminates complex mounting requirements.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If conventional vibrating wire design is used, then deformation measurement can be achieved, but drift over time occurs and measurement precision decreases

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddrift over time
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent replaces the electromagnetic interaction system with a direct piezoelectric-mechanical coupling system. This substitution eliminates the magnetic field generation and interaction components that introduced drift and instability, providing a more stable measurement system with improved long-term precision.

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

Significantly reduces power consumption, enhances sensitivity, and provides a compact design with minimal drift, enabling precise deformation and force measurement without magnetic fields or high shock-risk components.

Implementation Method 1

the vibrating wire has a piezoelectric activation layer, power consumption can be significantly reduced compared to conventional designs

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the piezoelectric activation layer has different lengths depending on the activation state, the vibrating string is deformed along its length in the manner of a bimetallic spring, which is particularly suitable for generating vibrations in a string

Methodology Applied
Scientific EffectBimetallic spring deformation: Bi-Metallic Strip

Data Source

PatentEP3583394B1Vibrating wire sensor and vibrating wire for a vibrating wire sensor
Publication Date: 2024.12.18 DIGISENS
  • EP3583394B1 patent drawingFigure 1
  • EP3583394B1 patent drawingFigure 2a
  • EP3583394B1 patent drawingFigure 2b

AI summary

The invention relates to a vibrating wire sensor (20, 30, 40 and 50) having a vibrating wire (21, 31, 41 and 51), which is tensioned accordingly differently under measurement conditions of a current factor to be detected, and having an exciter arrangement for exciting the vibrating wire (21, 31, 41 and 51) in the range of the respective natural frequency thereof, wherein the exciter arrangement has at least one exciter layer (22, 32, 42 and 52) provided on a longitudinal portion of the vibrating wire (21, 31, 41 and 51), having a piezoelectric activation layer (33, 46 and 54), which has a different length depending on the activation state, and thus creates a correspondingly different vibration position of the vibrating wire (21, 31, 41 and 51). A vibrating wire sensor can thus be designed to be more robust, wherein the power consumption is additionally considerably less. The invention further relates to a vibrating wire having an exciter layer (22, 32, 42 and 52), which has a piezoelectric activation layer.