Weight classification system

• US 7,048,085 B2
• Filed: 06/25/2003
• Issued: 05/23/2006
• Est. Priority Date: 09/29/2000
• Status: Expired due to Fees

• Current Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Original Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Inventors: Reich, Daniel, Graf, Robert, Morrell, Scott, Lichtinger, Harald, Curtis, Brian M., Kremer, Maria
• Primary Examiner(s): Gibson, Randy W.
• Application Number:
  US10/603,992
• Publication Number:
  US 20040016577A1
• Time in Patent Office: 1,063 Days
• Field of Search: 180/273, 280/735, 701/45, 177/136, 177/144, 177/210.R, 738/623.91
• US Class Current: 180/273
• 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: B60R 2021/01006 Mounting of electrical components in vehicles
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/0155 sensing belt tension
• CPC Class Codes: B60R 21/01556 Child-seat detection systems
• CPC Class Codes: B60R 22/18 Anchoring devices
• 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

Abstract

A method and apparatus is provided that classifies a seat occupant into one of several different weight classes based on an estimated value of the seat occupant weight. An occupant'"'"'s measured weight varies when the occupant'"'"'s seating position changes or when the vehicle travels over adverse road conditions. A plurality of weight sensors are used to measure the weight exerted by a seat occupant against a seat bottom and are used to determine center of gravity for the seat occupant. A seat belt force sensor is also used to assist in classifying the seat occupant. Compensation factors using the seat belt force and center of gravity information are used to generate an estimated weight value. The estimated value of the occupant weight is compared to a series of upper and lower weight thresholds assigned to each of the weight classes to generate an occupant weight sample class. Over a period of time, several estimated weight values are compared to the weight class thresholds. Once a predetermined number of consistent and consecutive occupant weight sample classes is achieved, the occupant is locked into a specific occupant weight class. When the weight class is locked, the separation value between the upper and lower thresholds is increased to account for minor weight variations due to adverse road conditions and changes in occupant position.

Claims

1. A vehicle weight classification system comprising:

a seat assembly having a seat frame for supporting a seat bottom;

a seat belt assembly for securing a seat occupant to said seat assembly;

a rigid member attached to said sear belt assembly and having a first end for supporting a seat belt portion and a second end integrally formed with said first end for attachment to a vehicle structure;

a plurality of weight sensors mounted to said seat frame for generating a plurality of weight signals in response to a weight force applied to said seat bottom;

at least one seat belt force sensor for generating a seat belt force signal, said seat belt force sensor being mounted on said rigid member between said first and second ends for measuring a force exerted on said rigid member by a tension force applied to said seat belt portion;

an electronic control unit for receiving said weight signals and seat belt force signals to determine occupant weight and center of gravity, generating an occupant classification based on said occupant weight and center of gravity, and transmitting an output control signal based on said occupant classification;

an airbag module for receiving said output control signal to control airbag deployment based on said occupant classification;

said seat assembly including a seat mount for attachment to a vehicle floor and said plurality of weight sensors comprises a first sensor mounted at a front right side corner of said seat bottom between said seat frame and said seat mount, a second sensor mounted at a front left side corner of said seat bottom between said seat frame and said seat mount a third sensor mounted at a rear right side corner of said seat bottom between said seat frame and said seat mount and a fourth sensor mounted at a rear left side corner of said seat bottom between said seat frame and said seat mount; and

said first end of said rigid member being positioned at an angle relative to said second end of said rigid member with said seat belt force sensor being directly mounted to said rigid member adjacent said second end.

2. A system according to claim 1, including an electrical connector mounted directly to said rigid member adjacent to said seat belt force sensor for receiving strain measurements from said strain gage and transmitting said measurements to said electronic control unit to determine the magnitude of the tension force.

3. A system according to claim 2 wherein said rigid member includes a neck portion positioned between said first and second ends having a width that is less than the width of said first and second ends and wherein said seat belt force sensor is mounted on said neck portion.

4. A system according to claim 3 wherein said first end includes an elongated slot for a loop attachment to said seat belt portion and said second end includes at least one aperture for receiving a fastener for attachment to the vehicle structure and wherein said electrical connector is mounted to said rigid member adjacent to said second end between said aperture and said neck portion.

5. A system according to claim 3 wherein said first end of said rigid member is positioned at an angle relative to said neck portion and said second end of said rigid member.

6. A system according to claim 3 wherein said electrical connector includes a main body portion for supporting at least one electrical component, said main body portion being directly mounted to said rigid member between said neck portion and said second end.

7. An assembly according to claim 6 wherein said main body member comprises a rigid housing member and wherein said at least one electrical component comprises a microprocessor mounted within said rigid housing member.

8. A system according to claim 7 wherein said at least one seat belt force sensor comprises at least one strain gage assembly.

9. A system according to claim 8 wherein each of said weight sensors includes a first end mounted to a seat track member with a first fastener, a second end mounted to a vehicle structure with a second fastener, and a central bendable portion that extends between said first and second ends.

10. A system according to claim 9 including a strain gage assembly mounted to said central bendable portion and an electronics package with a flexible printed circuit board and an application specific integrated circuit, said electronics package being in electrical communication with said swain gage assembly.

11. A system according to claim 10 wherein said central bendable portion includes a first surface and a second surface facing in an opposite direction from said first surface wherein one of said first or second surfaces includes a groove and the other or said first or second surfaces supports said strain gage assembly.

12. A system according to claim 10 wherein said electronic control unit includes a plastic housing with integrated insert molded sealed connectors for attachment and connection to said weight sensors.

13. A vehicle weight classification system comprising:

a seat assembly having a seat frame for supporting a seat bottom;

a seat belt assembly for securing a seat occupant to said seat assembly;

a rigid member attached to said seat belt assembly and having a first end for supporting a seat belt portion and a second end integrally formed with said first end for attachment to a vehicle structure;

a plurality of weight sensors mounted to said seat frame for generating a plurality of weight signals in response to a weight force applied to said seat bottom;

at least one seat belt force sensor for generating a seat belt force signal, said seat belt force sensor being mounted on said rigid member between said first and second ends for measuring a force exerted on said rigid member by a tension force applied to said seat belt portion;

an electronic control unit for receiving said weight signals and seat belt force signals to determine occupant weight and center or gravity, generating an occupant classification based on said occupant weight and center of gravity, and transmitting an output control signal based on said occupant classification;

an airbag module for receiving said output control signal to control airbag deployment based on said occupant classification; and

said rigid member includes a body portion positioned between and integrally formed with said first and second ends and wherein said first end is directly coupled to seat belt material and said seat belt force sensor is directly mounted to said body portion.

14. A vehicle weight classification system comprising:

a seat assembly having a seat frame for supporting a seat bottom;

a seat belt assembly for securing a seat occupant to said seat assembly;

a rigid member having a body portion, a first end for supporting a seat belt portion of said seat belt assembly and a second end adapted for attachment to a fixed structure wherein said first and second ends are integrally formed with said body portion;

a plurality of weight sensors mounted to said seat frame for generating a plurality of weight signals in response to a weight force applied to said seat bottom;

at least one seat belt force sensor for generating a seat belt force signal, said seat belt force sensor being mounted on said body portion of said rigid member between said first and second ends for measuring a force exerted on said rigid member by a tension force applied to said seat belt portion;

an electronic control unit for receiving said weight signals and seat belt force signals to determine occupant weight and center of gravity, generating an occupant classification based on said occupant weight and center of gravity, and transmitting an output control signal based on said occupant classification to control airbag deployment based on said occupant classification; and

said first end of said rigid member is positioned at an angle relative to said second end of said rigid member with said sear belt force sensor being directly mounted to said rigid member adjacent said second end.

15. A vehicle weight classification system comprising:

a seat assembly having a seat frame for supporting a seat bottom;

a seat belt assembly for securing a seat occupant to said seat assembly;

a rigid member having a body portion, a first end for supporting a seat belt portion of said seat belt assembly and a second end adapted for attachment to a fixed structure wherein said first and second ends are integrally formed with said body portion;

a plurality of weight sensors mounted to said seat frame for generating a plurality of weight signals in response to a weight force applied to said seat bottom;

at least one seat belt force sensor for generating a seat belt force signal, said seat belt force sensor being mounted on said body portion of said rigid member between said first and second ends for measuring a force exerted on said rigid member by a tension force applied to said seat belt portion;

an electronic control unit for receiving said weight signals and seat belt force signals to determine occupant weight and center of gravity, generating an occupant classification based on said occupant weight and center of gravity, and transmitting an output control signal based on said occupant classification to control airbag deployment based on said occupant classification; and

said rigid member includes a neck portion positioned between said first and second ends having a width that is less than the width of said first and second ends and wherein said seat belt force sensor is mounted on said neck portion.