Resonant Frequency Vibrational Test Using Hopf Oscillator
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Solution Overview
Problem
Existing resonant frequency vibrational tests for components, particularly in space activities, face inefficiencies in terms of time, energy consumption, and result accuracy due to issues like high power consumption, stiffness tuning difficulties, alignment adjustments, and the need for compensation in control loops, with analog processing circuits and servo-valve fatigue.
Innovation Solution
A method and apparatus using a Hopf oscillator to adjust the exciter input signal in real-time based on Fourier series phase differences and smoothed magnitude control, employing motion sensors to measure component and exciter vibrations, and utilizing a signal generator to maintain precise frequency and magnitude adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional vibrational test apparatuses are used, then fatigue tests can be performed on components, but power consumption is high and test efficiency is low
Solution Approach 1:
The system dynamically adjusts the excitation frequency in real-time to track the resonant frequency of the component under test. The frequency control signal is continuously updated based on phase difference measurements, allowing the test to operate at optimal resonant conditions throughout the test duration, thereby improving efficiency and reducing power consumption.
Solution Approach 2:
The system employs a feedback mechanism where the phase difference between the exciter motion and component response is continuously measured and used to adjust the excitation frequency. This closed-loop control ensures the system maintains resonant operation, maximizing test efficiency while minimizing energy consumption compared to traditional open-loop vibrational testers.
2Reliability
If resonant frequency testing is performed without real-time frequency adjustment, then the test setup is simpler, but the test results become unreliable when resonant frequency shifts occur
Solution Approach 1:
The system uses phase difference feedback to continuously monitor and adjust the excitation frequency. By measuring the phase relationship between exciter input and component response, the system automatically tracks resonant frequency shifts, ensuring reliable test results even as the component degrades and its resonant frequency changes over time.
Solution Approach 2:
The patent replaces complex mechanical stiffness tuning and alignment adjustment mechanisms with an electronic frequency control system. Instead of physically adjusting the test setup to maintain resonance, the system electronically adjusts the excitation frequency based on phase difference measurements, simplifying the mechanical setup while improving reliability.
3Measurement precision
If FFT (fast Fourier transform) is used for frequency analysis, then processing is faster, but the frequency approximation reduces measurement precision
Solution Approach 1:
The patent replaces FFT-based frequency analysis with Fourier series analysis. This substitution provides exact frequency measurement at the excitation frequency rather than an approximation, eliminating the trade-off between processing speed and precision. The Fourier series approach directly calculates the fundamental frequency component, providing accurate resonance tracking without the computational overhead and approximation errors of FFT.
4Productivity
If high frequency vibration testing is performed, then test duration is reduced, but acceleration effects appear due to inertia and servo-valve fatigue occurs
Solution Approach 1:
The system dynamically adapts the excitation frequency to match the component's resonant frequency rather than operating at fixed high frequencies. This allows the test to proceed efficiently at resonant conditions without subjecting the servo-valve and load train to excessive acceleration effects, thereby maintaining system reliability while achieving accelerated testing through resonance rather than brute-force high-frequency operation.
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 efficient, precise, and stable resonant frequency vibrational testing by continuously adjusting the exciter input signal to match the component's shifting resonant frequency, reducing power consumption and improving test reliability.
Implementation Method 1
the resonant frequency of said component may shift
Implementation Method 2
the frequency control signal is based on the phase difference, obtained by Fourier series terms, between the vibration of the component and the vibration of the exciter
Data Source
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AI summary
This invention relates to a resonant frequency vibrational test and a method of subjecting a component to such a resonant frequency vibrational test.