ELECTRET TYPE VIBRATION DETECTION SYSTEM, METHOD OF CREATING EXTERNAL VIBRATION INFORMATION, METHOD OF CREATING TRANSFER FUNCTION INFORMATION REGARDING EXTERNAL VIBRATION, PROGRAM FOR CREATING EXTERNAL VIBRATION INFORMATION, AND PROGRAM FOR CREATING TRANSFER FUNCTION INFORMATION REGARDING EXTERNAL VIBRATION

• US 20150149123A1
• Filed: 02/28/2013
• Published: 05/28/2015
• Est. Priority Date: 05/30/2012
• Status: Active Grant

• Current Assignee: Tokyo Institute of Technology (National University Corporation Tokyo Institute of Technology), Omron Corporation
• Original Assignee: Tokyo Institute of Technology (National University Corporation Tokyo Institute of Technology), Omron Corporation
• Inventors: Masaki, Tatsuakira, Sasaki, Eiichi, Yamaguchi, Hiroshi, Nakao, Shinichi, Nishida, Hideshi
• Granted Patent: US 9,964,434 B2
• Time in Patent Office: Days
• US Class Current: 702/198
• CPC Class Codes: G01H 11/06 by electric means
• CPC Class Codes: G01M 5/0008 of bridges
• CPC Class Codes: G01M 7/00 Vibration-testing of structures; Shock-testing of structures G01M9/00 takes precedence

Abstract

An electret type vibration detection system has a vibration-powered generator that performs vibration-induced power generation by displacing on a basis of external vibration an electret group formed of a plurality of electrets and an electrode group having a plurality of electrode pairs in a relative movement direction to output a vibration-induced voltage between electrodes of the electrode pair, and a transfer function memory section that stores transfer function information that defines a correlation between a vibration velocity of the external vibration and an output power voltage of the vibration-powered generator in a range of a predetermined frequency included in the external vibration, wherein the transfer function information contains a transfer coefficient set according to each of a plurality of frequencies belonging to the predetermined frequency range to place the vibration velocity of the external vibration and the output power voltage of the vibration-powered generator in a predetermined proportional relationship.

Claims

1. An electret type vibration detection system comprising:

a vibration-powered generator that performs vibration-induced power generation by displacing on a basis of external vibration an electret group formed of a plurality of electrets and an electrode group having a plurality of electrode pairs in a relative movement direction to output a vibration-induced voltage between electrodes of the electrode pair;

a transfer function memory section that stores transfer function information that defines a correlation between a vibration velocity of the external vibration and an output power voltage of the vibration-powered generator in a range of a predetermined frequency included in the external vibration,

wherein the transfer function information contains a transfer coefficient set according to each of a plurality of frequencies belonging to the predetermined frequency range to place the vibration velocity of the external vibration and the output power voltage of the vibration-powered generator in a predetermined proportional relationship;

an output spectrum information computing section that performs a Fourier transform on the transition information relating to the output power voltage of the vibration-powered generator within a predetermined time period to compute output spectrum information relating to the output power voltage; and

a vibration velocity information creating section that creates vibration velocity information relating to the external vibration in the predetermined time period, based on the output spectrum information relating to the output power voltage of the vibration-powered generator computed by the output spectrum information computing section and the transfer function information stored in the transfer function memory section.

2. The electret type vibration detection system according to claim 1, further comprising:

a vibration displacement information creating section that creates vibration displacement information relating to the external vibration within the predetermined time period by integrating the vibration velocity information relating to the external vibration in the predetermined time period created by the vibration velocity information creating section.

3. The electret type vibration detection system according to claim 1,

wherein the vibration-powered generator comprises:

a casing that houses the electret group and the electrode group,

a fixing member that is provided with the electrode group and fixed to the casing side, and

a movable member that is provided with the electret group and that is capable of relatively moving on the basis of the external vibration while facing the fixing member, and

wherein ends of respective electrets included in the electret group along the relative movement direction at a possible maximum amplitude assumed when the movable member is vibrated by the external vibration do not cross an electrode-side interval between one of the electrodes of the electrode group and an electrode neighboring to the one of the electrodes.

4. A method of creating external vibration information, comprising:

obtaining transition information relating to an output power voltage within a predetermined time period from a vibration-powered generator that performs vibration-induced power generation by displacing on a basis of external vibration an electret group formed of a plurality of electrets and an electrode group having a plurality of electrode pairs in a relative movement direction by virtue of external vibration and outputs a vibration-induced voltage between electrodes of the electrode pair;

computing output spectrum information relating to the output power voltage by performing a Fourier transform on the obtained transition information relating to the output power voltage; and

creating vibration velocity information relating to external vibration within the predetermined period based on the computed output spectrum information and transfer function information that defines a correlation between the vibration velocity of the external vibration in a range of a predetermined frequency included in the external vibration and the output power voltage of the vibration-powered generator,

wherein the transfer function information contains a transfer coefficient set according to each of a plurality of frequencies belonging to the predetermined frequency range to place the vibration velocity of the external vibration and the output power voltage of the vibration-powered generator in a predetermined proportional relationship.

5. The method of creating external vibration information according to claim 4, further comprising:

creating vibration displacement information relating to the external vibration within the predetermined time period by integrating the created vibration velocity information relating to the external vibration in the predetermined time period.

6. The method of creating external vibration information according to claim 4,

wherein the vibration-powered generator comprises:

a casing that houses the electret group and the electrode group,

a fixing member that is provided with the electrode group and fixed to the casing side, and

a movable member that is provided with the electret group and that is capable of relatively moving on the basis of the external vibration while facing the fixing member, and

wherein ends of respective electrets included in the electret group along the relative movement direction at a possible maximum amplitude assumed when the movable member is vibrated on the basis of the external vibration do not cross an electrode-side interval between one of the electrodes of the electrode group and an electrode neighboring to the one of the electrodes.

7. A method of creating transfer function information that defines a correlation between an output power voltage in a range of a predetermined frequency included in external vibration and a vibration velocity of the external vibration in the predetermined frequency range in a vibration-powered generator that performs vibration-induced power generation by displacing on a basis of the external vibration an electret group formed of a plurality of electrets and an electrode group having a plurality of electrode pairs in a relative movement direction and outputs a vibration-induced voltage between electrodes of the electrode pair,

wherein the vibration-powered generator having comprises:

a casing that houses the electret group and the electrode group;

a fixing member that is provided with the electrode group and fixed to the casing side; and

a movable member provided with the electret group and that is capable of relatively moving on the basis of the external vibration while facing the fixing member, and

wherein ends of respective electrets included in the electret group along the relative movement direction at a possible maximum amplitude assumed when the movable member is vibrated by the external vibration being configured not to cross an electrode-side interval between one of the electrodes of the electrode group and an electrode neighboring to the one of the electrodes,

wherein the method comprises;

applying the external vibration of a plurality of frequencies belonging to the predetermined frequency range to the vibration-powered generator;

computing a transfer coefficient for placing the vibration velocity of the external vibration and the output power voltage of the vibration-powered generator in a predetermined proportional relationship corresponding to each of the frequencies based on transition information relating to the output power voltage of the vibration-powered generator corresponding to each of the plurality of frequencies when the external vibration of the plurality of frequencies is applied; and

creating transfer function information that defines a correlation between the vibration velocity of the external vibration and the output power voltage of the vibration-powered generator based on the transfer coefficient corresponding to each of the frequencies.

8. A program stored on a non-transitory computer-readable medium for creating external vibration information, the program causing a computer to create information regarding external vibration applied to a vibration-powered generator that performs vibration-induced power generation by displacing on a basis of external vibration an electret group formed of a plurality of electrets and an electrode group having a plurality of electrode pairs in a relative movement direction and outputs a vibration-induced voltage between electrodes of the electrode pair, the program causing the computer to perform:

obtaining transition information relating to an output power voltage within a predetermined time period from the vibration-powered generator;

computing output spectrum information relating to the output power voltage by performing a Fourier transform on the obtained transition information relating to the output power voltage; and

creating vibration velocity information relating to the external vibration within the predetermined period based on the computed output spectrum information and transfer function information that defines a correlation between the vibration velocity of the external vibration in a rage of a predetermined frequency included in the external vibration and the output power voltage of the vibration-powered generator,

wherein the transfer function information contains a transfer coefficient set according to each of a plurality of frequencies belonging to the predetermined frequency range to place the vibration velocity of the external vibration and the output power voltage of the vibration-powered generator in a predetermined proportional relationship.

9. The program stored on a non-transitory computer-readable medium for creating external vibration information according to claim 8, wherein the program further causes the computer to create vibration displacement information relating to the external vibration within the predetermined time period by integrating the created vibration velocity information relating to the external vibration in the predetermined time period.

10. The program stored on a non-transitory computer-readable medium for creating external vibration information according to claim 8,

wherein the vibration-powered generator comprises:

a casing that houses the electret group and the electrode group,

a fixing member that is provided with the electrode group and fixed to the casing side, and

a movable member that is provided with the electret group and that is capable of relatively moving on the basis of the external vibration while facing the fixing member, and

wherein ends of respective electrets included in the electret group along the relative movement direction at a possible maximum amplitude assumed when the movable member is vibrated by the external vibration do not cross an electrode-side interval between one of the electrodes of the electrode group and an electrode neighboring to the one of the electrodes.

11. A program stored on a non-transitory computer-readable medium for creating transfer function information regarding external vibration, the program causing a computer to create transfer function information that defines a correlation between an output power voltage in a range of a predetermined frequency included in the external vibration and a vibration velocity of the external vibration in the predetermined frequency range in a vibration-powered generator that performs vibration-induced power generation by displacing on a basis of the external vibration an electret group formed of a plurality of electrets and an electrode group having a plurality of electrode pairs in a relative movement direction and outputs a vibration-induced voltage between electrodes of the electrode pair,

wherein the vibration-powered generator comprises:

a casing that houses the electret group and the electrode group;

a fixing member that is provided with the electrode group and fixed to the casing side; and

a movable member that is provided with the electret group and that is capable of relatively moving on the basis of the external vibration while facing the fixing member, and

wherein ends of respective electrets included in the electret group along the relative movement direction at a possible maximum amplitude assumed when the movable member is vibrated by the external vibration being configured not to cross an electrode-side interval between one of the electrodes of the electrode group and an electrode neighboring to the one of the electrodes,

wherein the program causes the computer to execute perform;

applying external vibration of a plurality of frequencies belonging to the predetermined frequency range to the vibration-powered generator;

computing a transfer coefficient for placing the vibration velocity of the external vibration and the output power voltage of the vibration-powered generator in a predetermined proportional relationship corresponding to each of the frequencies based on transition information relating to the output power voltage of the vibration-powered generator corresponding to each of the plurality of frequencies when the external vibration of the plurality of frequencies is applied; and

creating transfer function information that defines a correlation between the vibration velocity of the external vibration and the output power voltage of the vibration-powered generator based on the transfer coefficient corresponding to each of the frequencies.