Vehicle occupant weight classification system

• US 6,845,339 B2
• Filed: 12/17/2002
• Issued: 01/18/2005
• Est. Priority Date: 07/12/2000
• Status: Expired due to Fees

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Siemens AG
• Inventors: Winkler, Gerd, Schicker, Gerald, Knueppel, Andreas
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): West, Jeffrey R
• Application Number:
  US10/321,994
• Publication Number:
  US 20030093249A1
• Time in Patent Office: 763 Days
• Field of Search: 702/33, 702/34, 702/41, 702/42, 702/81, 702/82, 702 84- 87, 702/94, 702/95, 702/98, 702/101, 702/102, 702/104, 702151-154, 702/173, 701/45, 280/735
• US Class Current: 702/173
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: G06V 40/10 Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
• CPC Class Codes: Y10T 74/18088 Rack and pinion type
• CPC Class Codes: Y10T 74/1967 Rack and pinion

Abstract

A vehicle occupant classification system categorizes vehicle occupants into various classes such as adult, child, infant, etc. to provide variable control for a vehicle restraint system such as an airbag. The classification system utilizes sensors that are installed in various locations in the vehicle. The sensors are used to generate a three-dimensional profile for the vehicle occupant. Various factors can affect the accuracy of this three-dimensional profile. Fuzzy logic is used to reduce some of the inaccuracies by providing multiple decision levels for various stages of the classification. Inaccuracies are also caused by sensors shifting within the system from their original position. This condition creates offset and the system evaluates this offset and generates a correction factor to provide a more accurate three-dimensional profile. Electrically erasable programmable read-only memory is used to reduce complications and inaccuracies associated with seat occupant weight sensors that have mounting configurations that vary depending upon the vehicle.

Claims

1. A method for determining vehicle occupant characteristics comprising the steps of:

(a) supporting a plurality of sensors in a seat structure;

(b) generating a signal from each of the sensors in response to an occupant interacting with the seat structure;

(c) dividing the seat structure into a plurality of zones with each zone including at least one of the sensors;

(d) assigning at least one reference cell to each zone;

(e) determining an information factor for the sensors by establishing a virtual sensor matrix;

(f) comparing the signals from each of the sensors to the information factor; and

(g) applying a correction factor by compiling the signals from the sensors in each zone into the respective reference cell, generating a zone signal from each reference cell, and mapping the zone signals into the virtual sensor matrix.

2. A method according to claim 1 including determining an original sensor arrangement having known sensor positions for each of the sensors and wherein step (g) further includes using the known sensor positions in each respective zone to determine offset.

10. A method according to claim 1 wherein each signal from step (b) forms a first set of occupant signals generated by the occupant applying a load to the seat structure in a first occupant configuration;

step (b) further includes determining an initial three dimensional profile from the first set of occupant signals to establish an initial occupant position, and generating a plurality of operational occupant signals from each sensor over time for establishing subsequent three dimensional profiles that correspond to a plurality of different occupant configurations;

step (c) further includes combining operational occupant signals from each zone to generate a zone output signal;

step (f) further includes comparing each three dimensional profile to the information factor; and

step (g) further includes correcting signal output values if the three dimensional profiles vary from the information factor by a predetermined amount.

13. A method according to claim 1 wherein step (f) further includes combining the signals from each of the sensors to generate a three dimensional profile.

14. A method according to claim 13 including the step of determining seat occupant weight based on output from the virtual sensor matrix.

15. A method according to claim 14 wherein step (g) further includes generating a corrected three dimensional profile based on output from the virtual sensor matrix.

3. A method for determining vehicle occupant characteristics comprising the steps of:

(a) supporting a plurality of occupant sensors in a seat structure;

(b) generating an initial set of occupant signals from the occupant sensors having a predefined sensor arrangement with known sensor calibrated values;

(c) dividing the seat structure into a plurality of zones with each zone including at least one of the occupant sensors;

(d) assigning at least one reference cell to each zone, compiling signals from the occupant sensors in each zone into the respective reference cell, and generating a reference cell output from each reference cell;

(e) determining an information factor for the occupant sensors based on the known sensor calibrated values;

(f) generating a plurality of operational occupant signals from each occupant sensor over time that correspond to a plurality of different occupant configurations and generating a plurality of three dimensional profiles based on the different occupant configurations;

(g) comparing the three dimensional profiles to the information factor; and

(h) applying a correction factor based on reference cell output from each reference cell in step (d) to generate a corrected three dimensional profile if the three-dimensional profile varies from the information factor by a predetermined amount.

4. A method according to claim 3 including the step of defining system offset as the difference between the known sensor calibrated values and the operational occupant signals generated in step (f).

5. A method according to claim 4 wherein the initial set of occupant signals corresponds to at least one predetermined occupant configuration and wherein at least one of the operational occupant signals corresponds to the same predetermined occupant configuration.

6. A method according to claim 5 wherein each of the signals in the initial set of occupant signals for the predetermined occupant configuration has a first signal value based on the known sensor calibrated values, each of the operational occupant signals for the predetermined occupant configuration has a second signal value different than the first signal value, and further defining the system offset as the difference between the first and second signal values.

7. A method according to claim 6 including the steps of determining an offset correction factor for the occupant sensors in each zone based on the system offset and modifying the three dimensional profile by the respective offset correction factor to generate the corrected three dimensional profile.

8. A method according to claim 3 wherein step (d) further includes generating a zone output signal for each zone.

11. A method according to claim 3 wherein step (b) includes generating the initial set of occupant signals in response to an occupant applying a load to the seat structure;

step (c) further includes assigning each of the occupant sensors to a zone with each zone including more than one occupant sensor, and step (g) further includes combining the operational occupant signals in each zone to generate a zone output signal from each zone, mapping each zone output signal into a virtual sensor matrix, and determining occupant weight based on output from the virtual sensor matrix.

16. A method according to claim 8 wherein step (e) also includes determining the information factor by establishing a virtual sensor matrix defining a predetermined maximum number of occupant sensor positions;

and wherein step (h) further includes mapping the zone output signals into the virtual sensor matrix and determining the corrected three dimensional profile based on output from the virtual sensor matrix.

9. A system for determining vehicle occupant characteristics comprising:

a seat bottom divided into a plurality of zones;

a plurality of sensors mounted within said seat bottom with each zone including at least one sensor wherein each sensor generates a sensor output signal;

a plurality of reference cells with one reference cell being associated with one zone wherein each of said reference cells compiles the sensor output signals for all of said sensors mounted within said respective zone;

a control unit for generating a three dimensional profile representing an occupant position wherein said control unit corrects the three dimensional profile based on output from the reference cells.

12. A system according to claim 9 wherein each zone includes more than one sensor with said sensors generating a first set of occupant signals in response to an occupant load to said seat bottom in a first occupant configuration and wherein said sensors generate a plurality of operational occupant signals over time that correspond to a plurality of different occupant configurations, said control unit determining said three dimensional profile based on said first set of occupant signals, combining said operational occupant signals from each zone to generate a zone output signal, mapping said zone output signal from each zone into a virtual sensor matrix, and correcting the three dimensional profile based on output from the virtual sensor matrix.

17. A system according to claim 9 including an information factor with a predetermined virtual sensor matrix wherein said control unit maps output from said reference cells into said virtual sensor matrix to correct said three dimensional profile.

18. A system according to claim 17 wherein said virtual sensor matrix defines a maximum number of sensor positions and wherein the number of sensors within said seat bottom is less than said maximum number of sensor positions.

19. A system according to claim 18 wherein said sensors include a predefined sensor arrangement generating predefined calibrated sensor output values and wherein said control unit compares actual sensor values used to generate said three dimensional profiles to said predefined calibrated sensor output values to determine system offset.

20. A system according to claim 19 wherein said control unit generates a correction factor if said offset is greater than a predetermined amount and applies said correction factor to generate a corrected three dimensional profile.