Infrared out-of-position detection system and method for a vehicle restraint system

• US 20030204363A1
• Filed: 04/28/2003
• Published: 10/30/2003
• Est. Priority Date: 03/01/1999
• Status: Active Grant

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Griffin, Dennis P., Fultz, William W., Wu, Cunkai
• Granted Patent: US 6,766,271 B2
• Time in Patent Office: Days
• US Class Current: 702/150
• CPC Class Codes: B60R 21/01534 using electromagneticwaves, e.g. infrared
• CPC Class Codes: B60R 21/01542 detecting passenger motion
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/487 Extracting wanted echo signals , e.g. pulse detection
• CPC Class Codes: G06V 10/143 Sensing or illuminating at different wavelengths
• CPC Class Codes: G06V 20/59 inside of a vehicle, e.g. relating to seat occupancy, driver state or inner lighting conditions
• CPC Class Codes: G06V 40/10 Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands

Abstract

An improved infrared occupant detection system that provides accurate and reliable occupant intrusion information at a speed sufficient to timely inhibit or otherwise control deployment of occupant restraints. An array of infrared emitters is selectively activated to emit a predetermined pattern of IR beams in an area between the passenger seat and the point of deployment of the restraint, and the reflected IR energy is detected by a photo-sensitive receiver and analyzed to determine whether an occupant is out of position for deployment of the restraint. In the preferred embodiment, the intensity of the received beam energy and the position of the respective beam are used to construct a table of individual intrusion factors, and a composite intrusion factor based on the individual intrusion factors is categorized by magnitude to form an indication of occupant intrusion level, which in turn, is used to determine whether, or how forcefully, to deploy the restraint in the event of a serious crash.

Claims

1. A system for detecting the position of an occupant of a motor vehicle including an IR transmitter for emitting a beam of IR light for reflection off the occupant, an IR receiver for receiving the reflected IR light, and a controller coupled to the IR transmitter and IR receiver for determining the position of the occupant relative to a predefined out-of-position zone of the vehicle, the improvement wherein:

the IR transmitter includes an array of IR light emitters that are consecutively activated to emit individual beams of IR light in a predetermined pattern within said out-of-position zone;

the IR receiver generates an output signal corresponding to an intensity of the reflected IR light for each of the emitted IR beams; and

the controller;

determines an individual intrusion factor for each emitted IR beam based a comparison of the receiver output signal for that beam and a threshold intensity for that beam;

determines a composite intrusion factor based on the individual intrusion factors for all of the emitted beams; and

develops an out-of-position signal based on the composite intrusion factor for indicating a relative intrusion of the occupant into the out-of-position zone.

2. The improvement of claim 1, wherein any given individual intrusion factor is determined according to an amount by which a respective receiver output signal exceeds a respective threshold intensity.

3. The improvement of claim 2, wherein the given individual intrusion factor is set to zero if the respective receiver output signal is less than the respective threshold intensity.

4. The improvement of claim 1, wherein the threshold intensity for determining a given individual intrusion factor is determined according to a position of the respective emitted IR beam in said out-of-position zone.

5. The improvement of claim 1, wherein the individual intrusion factor for a given emitted IR beam includes a gain factor determined according to a position of the given emitted IR beam in said out-of-position zone.

6. The improvement of claim 1, wherein the composite intrusion factor indicates a degree of truth that the occupant has intruded into the out-of-position zone.

7. The improvement of claim 1, wherein the out-of-position signal is determined by comparing the composite intrusion factor to a plurality of predefined thresholds defining different levels of occupant intrusion into the out-of-position zone.

8. The improvement of claim 1, wherein the controller outputs the out-of-position signal to an occupant restraint system for determining whether or how forcefully to deploy occupant restraints, and the controller outputs a newly developed out-of-position signal only if it differs from the previously developed out-of-position signal.

9. A method of detecting intrusion of an occupant of a motor vehicle into a predefined out-of-position zone of the vehicle, including the steps of:

emitting successive beams of IR light in a predetermined pattern within said out-of-position zone for reflection off the occupant;

receiving reflected IR light beams, and generating an output signal corresponding to an intensity of the received IR light beam for each of the emitted IR light beams;

determining an individual intrusion factor for each emitted IR light beam based a comparison of a respective output signal and a respective threshold intensity;

determining a composite intrusion factor based on the individual intrusion factors for all of the emitted IR light beams; and

developing an out-of-position signal based on the composite intrusion factor for indicating a relative intrusion of the occupant into the out-of-position zone.

10. The method of claim 9, wherein any given individual intrusion factor is determined according to an amount by which a respective receiver output signal exceeds a respective threshold intensity.

11. The method of claim 10, wherein the given individual intrusion factor is set to zero if the respective receiver output signal is less than the respective threshold intensity.

12. The method of claim 9, wherein the threshold intensity for determining a given individual intrusion factor is determined according to a position of a respective emitted IR beam in said out-of-position zone.

13. The method of claim 9, wherein the individual intrusion factor for a given emitted IR beam includes a gain factor determined according to a position of the given emitted IR beam in said out-of-position zone.

14. The method of claim 9, wherein the composite intrusion factor indicates a degree of truth that the occupant has intruded into the out-of-position zone.

15. The method of claim 9, wherein the out-of-position signal is determined by comparing the composite intrusion factor to a plurality of predefined thresholds defining different levels of occupant intrusion into the out-of-position zone.

16. The method of claim 9, including the steps of:

outputting the out-of-position signal to an occupant restraint system for determining whether or how forcefully to deploy occupant restraints; and

outputting a newly developed out-of-position signal only if it differs from the previously developed out-of-position signal.