Occupant classification system

• US 20070192007A1
• Filed: 01/26/2007
• Published: 08/16/2007
• Est. Priority Date: 01/26/2006
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Acquisition, LLC (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Stanley, James, Theos, George, Maguire, Phil, McDonald, Don
• Granted Patent: US 8,818,637 B2
• Time in Patent Office: Days
• US Class Current: 701/45
• CPC Class Codes: A61P 9/12 Antihypertensives
• CPC Class Codes: B60N 2/0026 for distinguishing between humans, animals or objects
• CPC Class Codes: B60N 2/0035 characterised by the sensor data transmission, e.g. wired connections or wireless transmitters therefor; characterised by the sensor data processing, e.g. seat sensor signal amplification or electric circuits for providing seat sensor information
• CPC Class Codes: B60N 2/5685 Resistance
• CPC Class Codes: B60N 2210/12 Capacitive; Electric field
• CPC Class Codes: B60N 2230/10 Wired data transmission
• CPC Class Codes: B60R 21/01532 using electric or capacitive field sensors
• CPC Class Codes: B60R 21/0154 in combination with seat heating

Abstract

An occupant classification system classifies occupants on a vehicle seat and is capable of separating child seats from adults during wet seat cases. In the system, the seat structure is grounded. The classification system includes a measurement circuit, an identifying circuit, and a controller. The measurement circuit is configured to measure in-phase and quadrature components of a current sent out to the sensing element. The identifying circuit is configured to identify if a seat pan and a seat back frame of the vehicle seat are grounded to a circuit ground. The controller is configured to use measurements of the measurement circuit to classify the occupant. The sensing element can be located in a sensing mat that further includes a heating element.

Claims

1. An occupant classification system comprises:

a sensing element in a vehicle seat, the sensing element comprises a sensing electrode;

a measurement circuit that is configured to measure in-phase and quadrature components of a current sent out to the sensing electrode;

a circuit that is configured to identify if a seat pan or seat back frame of the vehicle seat are grounded to a circuit ground; and

a controller that is configured to classify an occupant by using measurements of the measurement circuit.

2. The occupant classification system of claim 1, wherein the sensing electrode is insulated from seat foam and a seat cover of the vehicle seat.

3. The occupant classification system of claim 1, wherein the sensing electrode comprises insulated wire.

4. The occupant classification system of claim 1, wherein the sensing electrode comprises a conductor deposited on a carrier.

5. The occupant classification system of claim 1, wherein during a wet seat situation, the controller is configured to separate an adult classification from a child seat classification when classifying the occupant on the vehicle seat.

6. An occupant classification system comprising:

a sensing element in a vehicle seat, the sensing element comprises a sensing electrode;

a measurement circuit that is configured to measure a current sent out to the sensing electrode;

at least one wire that connects a seat pan or seat back frame of the vehicle seat to a circuit ground or a chassis ground; and

a controller that is configured to classify the occupant by using measurements of the measurement circuit.

7. The occupant classification system of claim 6, wherein during a wet seat situation, the controller is configured to separate an adult from a child seat when classifying the occupant.

8. The occupant classification system of claim 7, wherein the measurement circuit is configured to measure in-phase and quadrature components of the current.

9. The occupant classification system of claim 7, further comprising a circuit configured to identify if a seat pan or seat back frame of the vehicle seat are grounded to a circuit ground.

10. The occupant classification system of claim 7, wherein the sensing electrode is insulated from seat foam and a seat cover of the vehicle seat.

11. The occupant classification system of claim 7, wherein the sensing electrode comprises insulated wire.

12. The occupant classification system of claim 7, wherein the sensing electrode comprises a conductor deposited on a carrier.

13. An occupant classification system, comprising:

a vehicle seat with a seat pan and a seat back frame;

a sensing element in a vehicle seat, the sensing element comprises a sensing electrode;

a measurement circuit to measure current sent to the sensing electrode;

a circuit to identify if the seat pan or seat back frame are grounded to a circuit ground; and

a controller to classify an occupant of the vehicle seat using measurements from the measurement circuit,

wherein during a wet seat situation, the controller is configured to separate an adult from a child seat when classifying the occupant.

14. The occupant classification system of claim 13, wherein the sensing electrode is insulated from seat foam and a seat cover of the vehicle seat.

15. The occupant classification system of claim 13, wherein the sensing electrode comprises insulated wire.

16. The occupant classification system of claim 13, wherein the sensing electrode comprises a conductor deposited on a carrier.

17. The occupant classification system of claim 13, wherein the measurement circuit is configured to measure in-phase and quadrature components of the current.

18. An occupant classification system comprises:

a sensing element in a vehicle seat;

a measurement circuit that is configured to measure in-phase and quadrature components of a current sent out to the sensing element;

a circuit that is configured to identify if a seat pan or seat back frame of the vehicle seat are grounded to a circuit ground; and

a controller that is configured to classify an occupant by using measurements of the measurement circuit,

wherein during a wet seat situation, the controller is configured to separate a classification of an adult from a child seat when classifying the occupant of the vehicle seat.

19. The occupant classification system of claim 18, wherein the sensing element is formed in a sensing mat in the vehicle seat.

20. The occupant classification system of claim 19, further comprising a heating element formed in the sensing mat, wherein the sensing element and heating element are positioned a predetermined distance apart.

21. An occupant classification system, comprising:

a sensing mat;

a sensing element formed in the sensing mat; and

a heating element formed in the sensing mat, wherein the sensing element and heating element are positioned a predetermined distance apart.

22. The occupant classification system of claim 21, wherein the sensing element and heating element are composed of conductive wire sewn into the sensing mat.

23. The occupant classification system of claim 21, further comprising a thermistor formed in the sensing mat for measuring the temperature of the heating element.

24. The occupant classification system of claim 23, further comprising:

a heater controller operatively connected to the heating element and the thermistor for controlling the heating element.

25. The occupant classification system of claim 21, further comprising:

a controller operatively connected to the sensing element and the heating element, wherein the controller is configured to monitor the heating element and if necessary, ground the heating element.

26. The occupant classification system of claim 25, wherein the controller further comprises:

a signal generator;

a microprocessor; and

signal detection circuitry for monitoring the heating element.

27. The occupant classification system of claim 25, wherein the controller is configured to ground the heating element at a sensing frequency of the sensing element.

28. The occupant classification system of claim 25, wherein the sensing element is configured to detect an occupant sitting in a vehicle seat and send a signal characterizing the occupant to the controller.

29. The occupant classification system of claim 25, wherein the controller is configured to analyze signals received from the sensing element to classify an occupant sitting on the vehicle seat.

30. The occupant classification system of claim 29, wherein during a wet seat situation, the controller is configured to separate an adult classification from a child seat classification when classifying the occupant on the vehicle seat.

31. An occupant classification system for a vehicle seat, comprising:

a sensing mat with a conducting sensing electrode;

a controller that is configured to perform electric field measurements near the sensing mat; and

at least one wire to connect the controller to at least one additional conductor, wherein potential of the at least one additional conductor influences the electric field near the sensing mat,

wherein the controller includes a mechanism to provide a low impedance between the at least one additional conductor and a controller circuit ground.

32. The occupant classification system of claim 31, wherein the sensing electrode comprises insulated wire.

33. The occupant classification system of claim 31, wherein the sensing electrode comprises a conductor deposited on a carrier.

34. The occupant classification system of claim 31, wherein the sensing electrode is insulated from seat foam and a seat cover of a vehicle seat.

35. The occupant classification system of claim 31, wherein the at least one additional conductor comprises a seat pan.

36. The occupant classification system of claim 31, wherein the at least one additional conductor comprises a seat back frame.