Folded Pendulum Angular Displacement Measurement

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Solution Overview

Problem

Current folded pendulum systems cannot independently measure angular and linear displacements due to combined signal acquisition, leading to undetermined measurements and sensitivity issues, particularly in seismic monitoring applications where decoupling of signals is crucial.

Innovation Solution

A method based on measuring the variation of the natural resonance frequency of the folded pendulum using models derived from analytical and numerical approaches, allowing for the extraction of angular displacement signals independently from linear signals, utilizing the Tait-Bryan angles to describe the orientation and relate it to the resonance frequency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If combined signal acquisition is used in folded pendulum systems, then measurement coverage is comprehensive, but signal decoupling becomes impossible leading to undetermined measurements

Engineering Contradiction:
Improvemeasurement coverageVSAvoidsignal decoupling accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the combined measurement signal into distinct angular and linear displacement components through mathematical decomposition. By separating the coupled signals into independent measurement channels, the system achieves both comprehensive measurement coverage and precise signal decoupling, resolving the technical contradiction between versatility and measurement accuracy.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If traditional folded pendulum configuration is used, then system simplicity is maintained, but sensitivity and decoupling between degrees of freedom are insufficient

Engineering Contradiction:
Improvesystem simplicityVSAvoidsensitivity
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces dynamic tuning capabilities to the folded pendulum system, allowing adjustment of resonance frequencies and measurement sensitivity. By making the system dynamically adjustable rather than static, it maintains structural simplicity while significantly improving sensitivity and decoupling performance through resonance-based measurement enhancement.

Inventive Principle:
Principle #15Dynamics

3Speed

If conventional displacement measurement is used, then measurement bandwidth is limited, but noise sensitivity is reduced

Engineering Contradiction:
Improvemeasurement bandwidthVSAvoidnoise sensitivity
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent exploits mechanical resonance vibrations of the folded pendulum system to enhance displacement measurement capabilities. By operating at resonant frequencies, the system achieves wide measurement bandwidth while the high Q-factor of resonance provides natural noise filtering, simultaneously improving speed of measurement and reducing noise sensitivity.

Inventive Principle:
Principle #18Mechanical vibration

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

Enables precise and independent measurement of angular displacements, improving sensitivity and decoupling between degrees of freedom, reducing noise sensitivity, and enhancing the scalability and adaptability of seismic monitoring sensors.

Implementation Method 1

measuring the variation of the natural resonance frequency of the folded pendulum using models derived from analytical and numerical approaches

Methodology Applied
Scientific EffectResonance frequency variation: Resonance

Implementation Method 2

a folded pendulum comprising a support F with a base, a test mass PM with an oscillation direction, a simple pendulum arm SP and an inverted pendulum arm IP that connect the test mass PM to the support F

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3177888B1Method for the measurement of angular and/or linear displacements utilizing one or more folded pendula
Publication Date: 2021.06.16 UNIVERSITA DEGLI STUDI DI SALERNO
  • EP3177888B1 patent drawingFigure 1
  • EP3177888B1 patent drawingFigure 2
  • EP3177888B1 patent drawingFigure 3

AI summary

The present invention concerns a system for the combined measurement of linear and angular displacements, with high sensitivity, wide measurement band at low frequency based on the configuration of the folded pendulum, and a linear and angular displacement sensor for applications of monitoring and control. Examples of possible applications of the combined sensor subject-matter of the present invention are sensor for the seismic monitoring, sensor for systems of monitoring and/or control of civil and industrial buildings, dykes, bridges, tunnels, etc., sensor for system of monitoring and/or control for the realization of systems of seismic attenuation and inertial platforms.