Impact detection system

• US 20080128600A1
• Filed: 11/30/2007
• Published: 06/05/2008
• Est. Priority Date: 12/01/2006
• Status: Active Grant

• Current Assignee: Subaru Corp., University of Tokyo
• Original Assignee: Fuji Jukogyo KK (Subaru Corp.), University of Tokyo
• Inventors: Takeda, Nobuo, Ogisu, Toshimichi, Nakamura, Noritsugu
• Granted Patent: US 7,696,471 B2
• Time in Patent Office: Days
• US Class Current: 250/227.18
• CPC Class Codes: G01D 5/35303 using a reference fibre, e.g. interferometric devices
• CPC Class Codes: G01D 5/35316 using a Bragg gratings
• CPC Class Codes: G01D 5/35387 using wavelength division multiplexing
• CPC Class Codes: G01M 11/083 by using an optical fiber in contact with the device under test [DUT]

Abstract

Disclosed is an impact detection system including: an optical fiber including a plurality of sensor sections to reflect light, a wavelength band of the reflected light vibrates depending on an elastic wave propagating through a subject to be inspected; a light source to input light into the optical fiber; optical filters each connected to an output terminal of the optical fiber; and an arithmetic processing unit to detect the impact from output values of sensor sections, wherein the wavelength bands of the sensor sections in the optical fiber are distributed such that the vibration bands caused by the impact to be detected do not overlap with each other, and a pass band of the optical filter corresponding to one of the sensor sections is distributed in the vibration band caused by the detection object, and is distributed in both sides of a center of the wavelength band of the one sensor section.

Claims

1. An impact detection system comprising:

an optical fiber including a core portion, the core portion including a plurality of sensor sections each provided with a grating portion, in which the grating portion is provided with a plurality of gratings each reflecting light, wavelength band of reflected light changes when a distance between the adjacent gratings changes, and the optical fiber vibrates the wavelength band depending on an elastic wave propagating through a subject to be inspected;

a light source to input light into the core portions of the optical fiber, in which a spectrum bandwidth of the light includes vibration bands of the wavelength bands of the sensor sections;

optical filters each connected to an output terminal of the optical fiber from which output terminal the reflected light is output; and

an arithmetic processing unit to perform arithmetic processing of output values of the plurality of sensor sections through the optical filters, so as to detect the impact to the subject, wherein

the wavelength bands of the sensor sections in the optical fiber are distributed to be apart from each other such that the vibration bands do not overlap with each other, and

a pass band of the optical filter corresponding to one of the sensor sections is distributed in the vibration band of the one sensor section, and is distributed in both sides of a center of the wavelength band of the one sensor section under no impact loaded.

2. The impact detection system according to claim 1, wherein

three or more pieces of the optical filters each having different pass bands corresponds to each one of the sensor sections.

3. The impact detection system according to claim 1, wherein

the arithmetic processing unit specifies a position and/or a magnitude of the impact loaded on the subject.

4. The impact detection system according to claim 1, wherein

the system includes m×

n pieces of the optical filters where m represents the number of the optical filters corresponding to each one of the sensor sections and is an integer of three or more, and n represents the number of the sensor sections included in one optical fiber and is an integer of two or more, and

the m×

n pieces of the optical filters are configured as a single arrayed waveguide grating (AWG) filter module including m×

n channels or more.