# US 12,000,760 B2 · Resonant frequency vibrational test

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- Number: US 12,000,760 B2
- Document ID: US12000760B2
- Status: Granted
- Kind: B2
- Application number: 17/440,211
- Filed: 2020-03-13
- Published: 2022-05-12
- Granted: 2024-06-04
- Earliest claimed: 2019-03-18
- Assignees: Universite de Mons
- Applicants: Universite De Mons
- Inventors: Lassaad Ben Fekih; Olivier Verlinden; Georges Kouroussis
- Web page: https://patentgrep.com/patent/US12000760B2

## CPC

- G01M 7/022: {Vibration control arrangements, e.g. for generating random vibrations}
- G01M 7/02: Vibration-testing {by means of a shake table}
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR

## Abstract

This invention relates to a resonant frequency vibrational test and a method of subjecting a component to such a resonant frequency vibrational test.

## Claims

### Claim 1

A method of subjecting a component to a resonant frequency vibrational test in which the component is excited in vibration by an exciter on the basis of an exciter input signal, the method comprising:
providing, based on measuring the vibration of the component, a target frequency signal indicative of a frequency control signal which is the phase difference between the vibration of the exciter and the vibration of the component, the vibration of the component being measured by a motion sensor; and
exciting the exciter in vibration with a smoothed exciter input signal, the exciter input signal having been adjusted by the target frequency signal in which the smoothed exciter input signal is provided by a Hopf oscillator driven by the target frequency signal.

### Claim 2 (depends on 1)

The method of claim 1, comprising:
providing, based on measuring the vibration of the component, a target magnitude signal indicative of a magnitude control signal which is the magnitude difference between the vibration of the component and a desired magnitude value, and
exciting the exciter in vibration with the smoothed exciter input signal, the exciter input signal having been adjusted by the target frequency signal and the target magnitude signal.

### Claim 3 (depends on 1)

The method of claim 1, comprising:
providing, based on measuring the vibration of the component, a smoothed target magnitude signal indicative of a magnitude control signal which is the magnitude difference between the vibration of the component and a desired magnitude value, and
exciting the exciter in vibration with the smoothed exciter input signal, the exciter input signal having been adjusted by the target frequency signal and the target magnitude signal.

### Claim 4 (depends on 1)

The method of claim 1, in which the smoothed exciter input signal is provided by:
smoothing the target frequency signal, and
using the smoothed target frequency signal to adjust the exciter input signal.

### Claim 5 (depends on 1)

The method of claim 1, in which the frequency control signal is smoothed by a method selected from rolling average or by a low-pass filter.

### Claim 6 (depends on 1)

The method of claim 1, in which the exciter input signal is continuously adjusted by the target frequency signal.

### Claim 7 (depends on 6)

The method of claim 6, in which the target frequency signal is adjusted by a frequency control according to the frequency control signal.

### Claim 8 (depends on 6)

The method of claim 6, in which the target frequency signal is adjusted by a proportional integral control, according to the smoothed frequency control signal.

### Claim 9 (depends on 6)

The method of claim 6, in which the frequency control provides a smoothed target frequency signal.

### Claim 10 (depends on 6)

The method of claim 6, in which a proportional integral control provides a smoothed target frequency signal.

### Claim 11 (depends on 1)

The method of claim 1, in which 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.

### Claim 12

A method of subjecting a component to a resonant frequency vibrational test in which the component is excited in vibration by an exciter on the basis of an exciter input signal, the method comprising:
providing, based on measuring the vibration of the component, a target frequency signal indicative of a frequency control signal which is the phase difference between the vibration of the exciter and the vibration of the component, the vibration of the component being measured by a motion sensor;
providing, based on measuring the vibration of the component, a target magnitude signal indicative of a magnitude control signal which is the magnitude difference between the vibration of the component and a desired magnitude value; and
exciting the exciter in vibration with the smoothed exciter input signal, the exciter input signal having been adjusted by the target frequency signal and the target magnitude signal;
in which the smoothed exciter input signal is provided by:
smoothing the target frequency signal, and
using the smoothed target frequency signal to adjust the exciter input signal;
in which the smoothed exciter input signal is provided by a Hopf oscillator driven by the target frequency signal;
in which the exciter input signal is continuously adjusted by the target frequency signal;
in which the target frequency signal is adjusted by a proportional integral control, according to the smoothed frequency control signal; and
in which the proportional integral control provides a smoothed target frequency signal.