Flexible optical impact detection sensor for front rail mounted airbag

• US 9,127,968 B2
• Filed: 11/18/2013
• Issued: 09/08/2015
• Est. Priority Date: 11/18/2013
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Cuddihy, Mark A., Rao, Manoharprasad K., Le, Jialiang
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): LANG, MICHAEL DEAN
• Application Number:
  US14/082,455
• Publication Number:
  US 20150142271A1
• Time in Patent Office: 659 Days
• Field of Search: 701/45
• US Class Current: 1/1
• CPC Class Codes: B60R 19/00 Wheel guards; Radiator guards, e.g. grilles; Obstruction removers; Fittings damping bouncing force in collisions reinforcement elements for side doors B60J5/0412; mudguards B62D
• CPC Class Codes: B60R 19/16 having deflecting members, e.g. rollers, balls
• CPC Class Codes: B60R 19/205 inflatable in the direction of an obstacle upon impending impact, e.g. using air bags
• CPC Class Codes: B60R 19/34 destroyed upon impact, e.g. one-shot type
• CPC Class Codes: B60R 19/483 with obstacle sensors of electric or electronic type
• CPC Class Codes: B60R 2021/0023 Offset collision
• CPC Class Codes: B60R 2021/01013 Means for detecting collision, impending collision or roll-over
• CPC Class Codes: B60R 21/00 Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks safety belts or body harnesses in vehicles B60R22/00; devices, apparatus or methods for life-saving in general A62B; safety devices for propulsion unit control specially adapted for, or arranged in, vehicles B60K28/00; seats constructed to protect the occupant from the effect of abnormal g-forces, e.g. crash or safety seats, B60N2/42; energy-absorbing arrangements for hand wheels for steering vehicles B62D1/11; energy-absorbing arrangements for vehicle steering columns B62D1/19; harnessing in aircraft B64D25/00
• 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
• CPC Class Codes: B60R 21/26 characterised by the inflation fluid source or means to control inflation fluid flow arrangement or mounting thereof to the vehicle B60R21/20; blasting cartridges for producing gas under pressure in general F42B3/04; initiators or igniters therefor F42B3/10
• CPC Class Codes: B62D 21/15 having impact absorbing means, e.g. a frame designed to permanently or temporarily change shape or dimension upon impact with another body bumpers B60R19/02; shock absorbers in general F16F
• CPC Class Codes: B62D 21/152 Front or rear frames
• CPC Class Codes: G01D 5/3537 Optical fibre sensor using a particular arrangement of the optical fibre itself

Abstract

A flexible optical impact detection sensor is mounted on an outboard portion of the front bumper for signaling an offset rigid barrier impact event to a forward corner of a motor vehicle and deployment of a small offset rigid barrier airbag mounted on the front rail. The airbag is attached proximate a distal end of a front rail. The flexible optical impact detection sensor, attached to a rear surface of an outboard portion of the front bumper, generates a signal upon a corner impact event, whereby a controller processes the signal generated by the impact detection sensor and electrically actuates an inflator upon a predetermined impact severity. The airbag in the inflated condition acts against the offset rigid barrier to generate a lateral force against the offset rigid barrier to push the motor vehicle away from the barrier and thereby redirect impact energy by lateral movement of the motor vehicle.

Claims

1. A sensing device for actuating an airbag system for mitigating intrusion in the event of an impact with an offset rigid barrier to a forward corner of a motor vehicle, the airbag system comprising a motor vehicle front rail having a forward projecting distal end, an airbag attached proximate the distal end of the front rail, the airbag having a stowed condition and an inflated condition, an inflator operationally coupled with the airbag responsive to electrical actuation for inflating the airbag with a gas, a flexible fiber optic impact detection sensor for generating a signal upon an impact event;

and a controller for processing the signal generated by the detection sensor and electrically actuating the inflator upon computing a predetermined impact severity to the forward corner of the motor vehicle, wherein the airbag in the inflated condition acts against the offset rigid barrier so as to generate a lateral force against the offset rigid barrier to push the motor vehicle away from the barrier and thereby redirect impact energy by lateral movement of the motor vehicle.

2. The sensing device of claim 1, wherein a front bumper beam is attached to the distal end of the front rail and the sensor is mounted to the bumper and adapted to measure bending in the bumper.

3. The sensing device of claim 2, wherein the sensor is mounted directly to an outboard portion of a rear side of the front bumper beam.

4. The sensing device of claim 3, wherein the sensor is bonded to a rear surface of the front bumper beam with an adhesive along substantially the entire length of the sensor in contract with the bumper.

5. The sensing device of claim 3, wherein the sensor is mounted to a rear surface of the front bumper beam at fixed points along its length.

6. The sensing device of claim 5, wherein the sensor is mounted to the rear of the front bumper beam at fixed points along its length by wire clamps attached to the sensor.

7. The sensing device of claim 3, wherein the rear surface of the front bumper beam further comprises a channel and the sensor is disposed within the channel.

8. The sensing device of claim 1, wherein the flexible fiber optic sensor comprises a fiber optic cable, a light source, a photodiode, and an amplifier, and wherein the light source sends a light signal through the fiber optic cable, which is received by the photodiode and in turn which outputs an electrical signal from the amplifier proportional to the quantum of light received.

9. The sensing device of claim 8, wherein the fiber optic cable consists of a core material surrounded by a thin layer of cladding material having a different index of refraction than that of the core material, and wherein the cladding is modified by partial removal of the cladding to form a bare portion on the core material such that bending the fiber optic cable changes the quantum of light that escapes from the fiber optic cable, whereby the signal of the photodiode will be changed, indicating the quantum of bending of the fiber optic cable.

10. The sensing device of claim 9, wherein the cladding is removed on only one side of the fiber optic cable to detect a directional signal indicating whether the fiber optic cable is bending towards the bare portion of the modified side of the fiber optic cable or away from it.

11. The sensing device of claim 9, wherein the flexible fiber optic sensor is adapted to provide a signal to detect an offset crash mode by mounting the fiber optic cable to a back surface of a front bumper beam and the distal portion of the front rail, thereby causing the flexible fiber optic sensor to sense any rearward bending of the front bumper beam.

12. The sensing device of claim 11, wherein the cladding is removed to form bare portions in predetermined areas along the length of the fiber optic cable at first regular intervals proximate the front bumper beam to detect local deformation of the front bumper beam.

13. The sensing device of claim 12, wherein the cladding is removed to form bare portions at second smaller intervals in a bend radius between the front bumper beam and the distal portion of the front rail to indicate deformation between the front bumper beam and the front rail.

14. The sensing device of claim 13, wherein a portion of the fiber optic cable mounted to the front rail has no cladding removed.

15. The sensing device of claim 8, wherein the light source is an infrared light emitting diode.

16. The sensing device of claim 8, wherein the photodiode is an infrared detector.

17. A method of deploying a motor vehicle airbag system, the method comprising the steps of:

providing a motor vehicle front rail having a forward projecting distal end;

providing an airbag having a stowed condition and an inflated condition;

equipping the airbag with an inflator operationally coupled with the airbag responsive to electrical actuation for inflating the airbag with a gas;

providing a flexible fiber optic sensor for generating a signal upon an offset impact event;

mounting the fiber optic cable to a back surface of a front bumper beam and the distal portion of the frame rail, thereby causing the flexible fiber optic sensor to sense any rearward bending of the front bumper beam;

providing a controller for processing the signal generated by the detection sensor; and

electrically actuating the inflator upon a predetermined impact severity to the vehicle.

18. The method of claim 17, wherein the flexible fiber optic sensor comprises a fiber optic cable, a light source, a photodiode, and an amplifier and wherein the method further comprises the steps of:

sending a light signal from the light source through the fiber optic cable;

receiving the light signal by the photodiode;

outputting an electrical signal from the amplifier proportional to the quantum of light received;

comparing the outputted electrical signal to a predetermined signal strength corresponding to the predetermined impact severity; and

deploying the airbag if the strength of the outputted electrical signal equals or exceeds the signal strength corresponding to the predetermined impact severity.

19. An airbag system for mitigating intrusion in the event of an impact with an offset rigid barrier to a forward corner of a motor vehicle, the airbag system comprising:

a motor vehicle front rail having a forward projecting distal end, an airbag attached proximate the distal end of the front rail, the airbag having a stowed condition and an inflated condition, an inflator operationally coupled with the airbag responsive to electrical actuation for inflating the airbag with a gas;

a flexible fiber optic impact detection sensor comprising a fiber optic cable, a light source, a photodiode, and an amplifier, the flexible fiber sensor adapted to generate a signal to detect an offset crash mode by mounting the fiber optic cable to a back surface of a front bumper beam and the distal portion of the front rail, thereby causing the flexible fiber optic sensor to sense any rearward bending of the front bumper beam, the fiber optic cable further comprising a core material surrounded by a thin layer of cladding material having a different index of refraction than that of the core material, wherein the cladding is modified by partial removal of the cladding to form a bare portion on the core material in predetermined areas along the length of the fiber optic cable at first regular intervals proximate the front bumper beam to detect local deformation of the front bumper beam such that bending the fiber optic cable changes the quantum of light that escapes from the fiber optic cable, and the cladding is removed to form bare portions at second smaller intervals in a bend radius between the front bumper beam and the distal portion of the front rail such that bending the fiber optic cable changes the quantum of light that escapes from the fiber optic cable to indicate deformation between the front bumper beam and the front rail, wherein the light source sends a light signal through the fiber optic cable that is received by the photodiode and in turn which outputs an electrical signal from the amplifier proportional to the quantum of light received, and the electrical signal of the photodiode changes to indicate the quantum of bending of the fiber optic cable;

and a controller for processing the signal generated by the detection sensor and electrically actuating the inflator upon computing a predetermined impact severity to the forward corner of the motor vehicle, wherein the airbag in the inflated condition acts against the offset rigid barrier so as to generate a lateral force against the offset rigid barrier to push the motor vehicle away from the barrier and thereby redirect impact energy by lateral movement of the motor vehicle.

20. The sensing device of claim 19, wherein a portion of the fiber optic cable mounted to the front rail has no cladding removed.