System and method for adjusting a zero point of a seat load sensing system

• US 20060167604A1
• Filed: 01/24/2005
• Published: 07/27/2006
• Est. Priority Date: 01/24/2005
• Status: Active Grant

• Current Assignee: TRW Automotive USLLC (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Automotive USLLC (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: David, Raymond J., Smith, Nick L., Hibner, Christopher
• Granted Patent: US 7,684,913 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 2/02 the seat or part thereof being movable, e.g. adjustable adjustable arm-rests B60N2/75; adjustable head-rests B60N2/806
• CPC Class Codes: B60N 2/0244 with logic circuits
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015
• CPC Class Codes: G01G 23/163 involving digital counting

Abstract

A method (60) for adjusting the zero point of a vehicle seat weight sensing system (10) includes the step of determining a zero point error (64) of the seat weight sensing system. The method (60) also includes the step of adjusting the zero point error (68) in response to determining that the zero point error was influenced by an object on the vehicle seat.

Claims

1. A method for adjusting the zero point of a vehicle seat weight sensing system, the method comprising the steps of:

determining a zero point error of the seat weight sensing system; and

adjusting the zero point error in response to determining that the zero point error was influenced by an object on the vehicle seat.

2. The method of claim 1, wherein said step of determining a zero point error comprises the steps of:

determining an unoccupied condition of the vehicle seat;

determining a sensed weight on the vehicle seat in response to determining the unoccupied condition; and

determining the zero point error in response to determining the sensed weight.

3. The method of claim 2, wherein said step of determining a sensed weight comprises determining the sensed weight in response to an output of a seat weight sensor associated with the vehicle seat.

4. The method of claim 1, further comprising the steps of:

determining whether the zero point error is within a predetermined range in response to determining that the zero point error was not influenced by an object on the vehicle seat; and

adjusting the zero point of the seat weight sensing system to help correct the zero point error in response to the zero point error being within the predetermined range.

5. The method of claim 2, wherein said step of determining an unoccupied condition of the vehicle seat comprises the step of waiting a predetermined time period after the vehicle ignition is deactivated.

6. The method of claim 2, wherein said step of determining an unoccupied condition of the vehicle seat comprises the step of determining whether a seatbelt is latched.

7. The method of claim 2, wherein said step of determining an unoccupied condition of the vehicle seat comprises the step of determining whether there are any fluctuations in a sensed seat weight for a predetermined time period.

8. The method of claim 1, wherein determining whether the zero point error was influenced by an object on the vehicle seat comprises the steps of:

determining the zero point error is not within a predetermined range;

determining a cumulative zero point adjustment value as the sum of previous zero point adjustments; and

determining the zero point error was influenced by an object on the vehicle seat if the cumulative zero point adjustment value is within the predetermined range.

9. The method of claim 8, further comprising the step of resetting said cumulative adjustment value to zero in response to determining the zero point error was influenced by an object on the vehicle seat.

10. The method of claim 2, wherein said step of determining an unoccupied condition of the vehicle seat comprises sensing at least one of a vehicle door opening and activation of a remote keyless entry system of the vehicle.

11. The method of claim 1, wherein determining whether the zero point error was influenced by an object on the vehicle seat comprises the steps of:

monitoring a sensed seat weight; and

determining the zero point error was influenced by an object on the vehicle seat in response to a decrease in the sensed seat weight.

12. The method of claim 1, further comprising the steps of:

monitoring a sensed seat weight; and

validating the zero point error in response to sensing an increase in the sensed seat weight.

13. The method of claim 1, further comprising the steps of:

monitoring a sensed seat weight; and

invalidating the zero point error in response to sensing a decrease in the sensed seat weight.

14. A method for adjusting the zero point of a vehicle seat weight sensing system, the method comprising the steps of:

determining an unoccupied condition of the vehicle seat;

determining a zero point error in response to determining the unoccupied condition;

determining the zero point error was influenced by an object on the vehicle seat if the zero point error is outside a predetermined range and a cumulative zero point adjustment value is within the predetermined range.

15. A method for adjusting the zero point of a vehicle seat weight sensing system, the method comprising the steps of:

determining a vehicle seat weight snapshot upon the occurrence of a predetermined vehicle event;

using the seat weight snapshot as a zero point error of the seat weight sensing system; and

determining the zero point error is invalid in response to determining a decrease in sensed seat weight subsequent to taking the seat weight snapshot.

16. A method for adjusting the zero point of a vehicle seat weight sensing system, the method comprising the steps of:

determining a vehicle seat weight snapshot upon the occurrence of a predetermined vehicle event;

using the seat weight snapshot as a zero point error of the seat weight sensing system; and

determining the zero point error is valid in response to determining an increase in sensed seat weight subsequent to taking the seat weight snapshot.

17. A vehicle seat weight sensing system comprising:

a seat weight sensor associated with a vehicle seat;

a controller operative to determine a sensed weight on the vehicle seat in response to an,output from said seat weight sensor, said controller comprising;

means for determining a zero point error of the seat weight sensing system; and

means for adjusting the zero point of the seat weight sensing system in response to determining that the zero point error was influenced by an object on the vehicle seat.

18. The system of claim 17, wherein said means for determining a zero point error comprises:

means for determining an unoccupied condition of the vehicle seat;

means for determining a sensed weight on the vehicle seat in response to determining the unoccupied condition; and

means for determining the zero point error in response to determining the sensed weight.

19. The system of claim 17, further comprising:

means for determining whether the zero point error is within a predetermined range in response to determining that the zero point error was not influenced by an object on the vehicle seat; and

means for adjusting the zero point of the seat weight sensing system to help correct the zero point error in response to the zero point error being within the predetermined range.

20. The system of claim 17, further comprising means for determining that the zero point error was influenced by an object on the vehicle seat, comprising:

means for determining the zero point error is not within a predetermined range;

means for determining a cumulative zero point adjustment value as the sum of previous zero point adjustments; and

means for determining the zero point error was influenced by an object on the vehicle seat if the cumulative zero point adjustment value is within the predetermined range.

21. The system of claim 17, further comprising means for determining that the zero point error was influenced by an object on the vehicle seat, comprising:

means for monitoring a sensed seat weight; and

means for determining the zero point error was influenced by an object on the vehicle seat in response to a decrease in the sensed seat weight.