Sensor assembly including a sensing channel having a void and an associated method

• US 20060180380A1
• Filed: 02/11/2005
• Published: 08/17/2006
• Est. Priority Date: 02/11/2005
• Status: Active Grant

• Current Assignee: TRW Automotive USLLC (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Automotive USLLC (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Munch, Carl A., McCarthy, Michael C.
• Granted Patent: US 7,445,073 B2
• Time in Patent Office: Days
• US Class Current: 180/274
• CPC Class Codes: B60R 2021/01095 optical
• CPC Class Codes: B60R 21/0136 responsive to actual contact with an obstacle , e.g. to vehicle deformation, bumper displacement or bumper velocity relative to the vehicle monitoring crash strength in combination with passenger seat detection B60R21/01558

Abstract

A sensor assembly (14) for sensing an impact to a vehicle (10) includes a light source (34) for emitting light and a sensing channel (40) for receiving the emitted light. The sensing channel (40) is configured to deform in response to an impact to the vehicle (10) and includes at least one void (70) with dimensions that vary in response to deformation of the sensing channel (40). A detector (36) senses an intensity of the light propagating through the sensing channel (40) and provides a signal indicative of the sensed intensity. The sensed intensity varies as a function of the dimensions of the at least one void (70). The sensor assembly (14) also includes a controller (94) for analyzing the signal from the detector (36) to determine whether the sensing channel (40) has been deformed and thereby, whether an impact to the vehicle (10) has occurred.

Claims

1. A sensor assembly for sensing an impact to a vehicle, the sensor assembly comprising:

a light source for emitting light;

a sensing channel for receiving the emitted light, the sensing channel configured to deform in response to an impact to the vehicle and including at least one void with dimensions that vary in response to deformation of the sensing channel;

a detector for sensing an intensity of the light propagating through the sensing channel and for providing a signal indicative of the sensed intensity, the sensed intensity varying as a function of the dimensions of the at least one void; and

a controller for analyzing the signal from the detector to determine whether the sensing channel has been deformed and thereby, whether an impact to the vehicle has occurred.

2. The sensor assembly of claim 1 further including a reference channel and a reference detector, the reference channel also receiving the emitted light and the reference detector sensing an intensity of the light propagating through the reference channel and providing a reference signal indicative of the sensed intensity, the controller using the reference signal for compensating for variations in an intensity of the light emitted from the light source.

3. The sensor assembly of claim 2 wherein the controller determines that an impact to the vehicle has occurred when a difference between the intensity of light propagating through the sensing channel and the intensity of light propagating though the reference channel exceeds a threshold.

4. The sensor assembly of claim 3 wherein the threshold varies as a function of the intensity of light propagating through the reference channel.

5. The sensor assembly of claim 2 wherein the detector for the sensing channel and the reference detector are photodiodes.

6. The sensor assembly of claim 5 wherein the photodiodes form separate portions of a single photodiode array.

7. The sensor assembly of claim 1 wherein the sensing channel is formed on a mat, the mat adapted to be secured relative to the vehicle in a location for sensing an impact to the vehicle.

8. The sensor assembly of claim 1 wherein the sensing channel is a fiber optic cable having a cladding, the at least one void extending completely through the cladding.

9. The sensor assembly of claim 1 wherein the light source is a light emitting diode that is adapted to provide pulses of light.

10. The sensor assembly of claim 1 wherein the dimensions of the at least one void increase in response to deformation of the sensing channel, the sensed intensity of the light decreasing as the dimensions of the at least one void increase.

11. The sensor assembly of claim 1 wherein the dimensions of the at least one void decrease in response to deformation of the sensing channel, the sensed intensity of the light increasing as the dimensions of the at least one void decrease.

12. A method for sensing an impact to a vehicle, the method comprising the steps of:

emitting light;

receiving the light in a sensing channel that is configured to deform in response to an impact to the vehicle and that includes at least one void having dimensions that vary in response to deformation of the sensing channel;

sensing an intensity of the light propagating through the sensing channel and providing a signal indicative of the sensed intensity, the sensed intensity varying as a function of the dimensions of the at least one void; and

analyzing the signal to determine whether the sensing channel has been deformed and thereby, determining whether an impact to the vehicle has occurred.

13. The method of claim 12 further including the steps of:

receiving the emitted light in a reference channel;

sensing an intensity of the light propagating through the reference channel and providing a reference signal indicative of the sensed intensity; and

using the reference signal to compensate for variations in an intensity of the light emitted from the light source.

14. The method of claim 13 further including the steps of:

determining that an impact to the vehicle has occurred when a difference between the intensity of light propagating through the sensing channel and the intensity of light propagating though the reference channel exceeds a threshold.

15. The method of claim 14 further including the step of varying the threshold as a function of the sensed intensity of light propagating through the reference channel.

16. The method of claim 12 wherein the step of emitting light further includes the step of emitting pulses of light.