Method and system for detecting occupant seat weight sensor measurement error

• US 20060106517A1
• Filed: 11/18/2004
• Published: 05/18/2006
• Est. Priority Date: 11/18/2004
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Bujak, Chris, Griffin, Christopher, Philip, Abraham
• Granted Patent: US 9,187,010 B2
• Time in Patent Office: Days
• US Class Current: 701/45
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60N 2/0025 by using weight measurement
• CPC Class Codes: B60N 2205/00 General mechanical or structural details
• CPC Class Codes: B60N 2230/30 Signal processing of sensor data
• CPC Class Codes: B60R 2225/00 Means indicating the functioning state of the alarm system, e.g. indicating arming, using leds

Abstract

A vehicle system includes a vehicle occupant seat includes at least two weight sensors coupled to the seat and generating weight signals. The system further includes an electronic control unit including an occupant classification algorithm generating an occupant classification signal as a function of the weight signals. The electronic control unit further includes variant signal metrics generating an error signal as a function of comparing the weight signals.

Claims

1. A vehicle system including a vehicle occupant seat comprising:

a first weight sensor coupled to the seat generating a first weight signal;

a second weight sensor coupled to the seat generating a second weight signal; and

an electronic control unit comprising an occupant classification algorithm generating an occupant classification signal as a function of said first weight signal and said second weight signal, said electronic control unit further comprising variant signal metrics generating an error signal as a function of comparing said first weight signal to said second weight signal.

2. The system of claim 1, wherein said electronic control unit compares said first weight signal to said second weight signal through comparing expected variance of said first weight signal and said second weight signal to a predetermined expected variance minimum of a functional sensor.

3. The system of claim 1, wherein said electronic control unit compares said first weight signal to said second weight signal through comparing expected gradients of said first weight signal and said second weight signal to a minimum expected gradient of a functional sensor.

4. The system of claim 1, wherein said electronic control unit compares said first weight signal to said second weight signal through comparing maximum expected negative weight of a non-constrained sensor with expected magnitude in said first weight signal and said second weight signal.

5. The system of claim 1, wherein said first weight sensor is coupled to a left portion of a base of the seat, said second weight sensor is coupled to a right side of said base of the seat.

6. The system of claim 5 further comprising a third weight sensor coupled to a left portion of a back of the seat generating a third weight signal;

and

a fourth weight sensor coupled to a right side of said back of the seat generating a fourth weight signal, wherein said electronic control unit, further comprising variant signal metrics generating said error signal as a function of comparing said third weight signal to said fourth weight signal.

7. The system of claim 1 further comprising a restraints control module activating safety systems as a function of at least one of said occupant classification signal and said error signal.

8. The system of claim 7, wherein said restraints control module disregards said occupant classification signal when said error signal indicates the seat is constrained.

9. A method for detecting weight sensor error for a vehicle having a first weight sensor and a second weight sensor coupled to a seatback, and a third weight sensor and a fourth weight sensor coupled to a seat base comprising:

generating a first sensor signal from the first weight sensor;

generating a second sensor signal from the second weight sensor;

generating a third sensor signal from the third weight sensor;

generating a fourth sensor signal from the fourth weight sensor;

comparing expected variance of said first sensor signal, said second sensor signal, said third sensor signal, and said fourth sensor signal to a predetermined expected variance minimum of a functional sensor;

comparing expected gradients of said first sensor signal, said second sensor signal, said third sensor signal, and said fourth sensor signal to a minimum expected gradient of a functional sensor;

comparing maximum expected negative weight of a non-constrained sensor with expected magnitude in said first sensor signal, said second sensor signal, said third sensor signal, and said fourth sensor signal; and

generating an error signal in response to an indication of a constrained seat generated as a function of at least one of said step of comparing expected variance, said step of comparing expected gradients, and said step of comparing maximum expected negative weight.

10. The method of claim 9 further comprising comparing expected variance of said third sensor signal to expected variance of said fourth sensor signal;

and generating an error signal in response to said step of comparing expected variance of said third sensor to expected variance of said fourth sensor.

11. The method of claim 9 further comprising comparing expected variance of said first sensor signal to expected variance of said second sensor signal;

and generating an error signal in response to said step of comparing expected variance of said first sensor to expected variance of said second sensor.

12. The method of claim 9 further comprising comparing expected variance of said third sensor signal and said fourth sensor signal to expected variance of said first sensor signal and said second sensor signal;

and generating an error signal in response to said step of comparing expected variance of said third sensor signal and said fourth sensor signal to expected variance of said first sensor signal and said second sensor signal.

13. The method of claim 9 further comprising comparing expected variance of said first sensor signal, said second sensor signal, said third sensor signal, and said fourth sensor signal to a minimum expected variance of a seat sensor system;

and generating an error signal in response to said step of comparing expected variance of said first sensor signal, said second sensor signal, said third sensor signal, and said fourth sensor signal to a minimum expected variance of a seat sensor system.

14. The method of claim 9 further comprising comparing expected variance of said first sensor signal and said fourth sensor signal to expected variance of said second sensor signal and said third sensor signal;

and generating an error signal in response to said step of comparing expected variance of said first sensor signal and said fourth sensor signal to expected variance of said second sensor signal and said third sensor signal.

15. The method of claim 9 further comprising comparing expected gradients of said third sensor signal to expected gradients of said fourth sensor signal;

and generating an error signal in response to said step of comparing expected gradients of said third sensor signal to expected gradients of said fourth sensor signal.

16. The method of claim 9 further comprising comparing expected gradients of said third sensor signal to expected gradients of said fourth sensor signal;

and generating an error signal in response to said step of comparing expected gradients of said third sensor signal to expected gradients of said fourth sensor signal.

17. The method of claim 9 further comprising comparing expected magnitude of said third sensor signal to expected magnitude of said fourth sensor signal;

and generating an error signal in response to said step of comparing expected magnitude of said third sensor signal to expected magnitude of said fourth sensor signal.

18. The method of claim 9 further comprising comparing expected magnitude of said first sensor signal to expected magnitude of said second sensor signal;

and generating an error signal in response to said step of comparing expected magnitude of said first sensor signal to expected magnitude of said second sensor signal.

19. A vehicle system including a vehicle occupant seat having a back and a base comprising:

a first weight sensor coupled to a left portion of the seat base generating a first weight signal;

a second weight sensor coupled to a right side the seat base generating a second weight signal;

a third weight sensor coupled to a left portion of the seat back generating a third weight signal;

a fourth weight sensor coupled to a right side the seat back generating a fourth weight signal;

an electronic control unit comprising an occupant classification algorithm generating an occupant classification signal as a function of said first weight signal, said second weight signal, said third weight signal, and said fourth weight signal, said electronic control unit further comprising variant signal metrics generating an error signal in response to an indication of a constrained seat generated as a function of at least one of

comparing expected variances of at least two of said first weight signal, said second weight signal, said third weight signal, and said fourth weight signal,

comparing expected gradients of at least two of said first weight signal, said second weight signal, said third weight signal, and said fourth weight signal, or

comparing maximum expected negative weight of at least two of said first weight signal, said second weight signal, said third weight signal, and said fourth weight signal; and

a restraints control module activating safety systems as a function of at least one of said occupant classification signal and said error signal.

20. The system of claim 19, wherein said restraints control module disregards said occupant classification signal when said error signal indicates the seat is constrained.