OCCUPANT DETECTION AND CLASSIFICATION SYSTEM

• US 20130027065A1
• Filed: 10/02/2012
• Published: 01/31/2013
• Est. Priority Date: 11/19/2009
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Acquisition, LLC
• Original Assignee: TK Holdings Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Stanley, James Gregory, Maguire, Phil
• Granted Patent: US 9,278,629 B2
• Time in Patent Office: Days
• US Class Current: 324/705
• 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 21/01512 Passenger detection systems
• CPC Class Codes: B60R 21/01532 using electric or capacitive field sensors
• CPC Class Codes: B60R 21/0154 in combination with seat heating
• CPC Class Codes: B60R 21/01544 detecting seat belt parameters, e.g. length, tension or height-adjustment

Abstract

An occupant detection system includes a controller, a sensing electrode, and a shield electrode, the electrodes disposed in a vehicle seat. The controller is electrically coupled to the sensing electrode and shield electrode by a sensing circuit. The controller is configured to send an input signal to the sensing electrode, the shield electrode, or both and measures current, impedance, or capacitance values to determine the presence of an object on the seat, to classify the object, or both.

Claims

1. A system for detecting an occupant in a vehicle comprising:

a sensing electrode mountable in a seat bottom of a vehicle seat;

a shield electrode located in the vehicle seat below the sensing electrode;

a sensing circuit operatively coupled to the sensing electrode and the shield electrode;

a controller operatively coupled to the sensing circuit, wherein the controller is configured to direct a current through the shield electrode, and wherein the sensing circuit is configured to provide a signal to the shield electrode and detect a change in a current through the shield electrode resulting from a change in the relative position of the sensing electrode to the shield electrode due to the weight of the object located on the vehicle seat.

2. The system of claim 1, wherein the controller is configured classify the object by calculating a change in impedance between the shield electrode and sensing electrode based on the change in current.

3. The system of claim 2, wherein the sensing electrode is grounded when the change in current is detected.

4. The system of claim 2, wherein the controller is configured to classify the occupant based on a plurality of measurements taken by the sensing circuit.

5. The system of claim 4, wherein the controller determines whether to activate a seat belt indicator or an air bag.

6. The system of claim 4, wherein a compressible material is disposed between the sensing electrode and the shield electrode.

7. The system of claim 2, wherein, the sensing circuit is configured to provide the signal to the sensing electrode and wherein the sensing circuit is configured to detect a change in the current to the sensing electrode due to an electric-field influencing property of an object on the vehicle seat;

and wherein the controller is configured to classify the object based on the change in current to the sensing electrode.

8. The system of claim 2, further comprising a belt tension sensor operatively coupled to the controller, and wherein the controller is configured to classify the object based on a signal from the belt tension sensor.

9. A system for detecting an occupant in a vehicle comprising:

a sensing electrode mountable in a seat bottom of a vehicle seat;

a shield electrode located in the vehicle seat below the sensing electrode;

a sensing circuit operatively coupled to the sensing electrode and the shield electrode;

a controller operatively coupled to the sensing circuit, wherein the controller operates to configure the sensing circuit to apply a plurality of signals to the shield electrode;

wherein the controller is configured to detect the presence of an object in the seat by detecting a relative force applied to the seat by the object and by calculating a force value related to the impedance between the sensing electrode and the shield electrode by using the results of separate measurements performed when each of the plurality of signals are applied to the shield electrode.

10. The system of claim 9, wherein a compressible material is disposed between the sensing electrode and shield electrode.

11. The system of claim 10, wherein the controller determines whether o activate a seat belt indicator or an air bag.

12. The system of claim 9, wherein each of the plurality of signals are substantially the same.

13. The system of claim 9, wherein one of the plurality of signals is applied to the sensing electrode and wherein the controller is configured to detect the presence of a wet seat by calculating a detection value related to the impedance from the sensing electrode to ground.

14. The system of claim 13, wherein the plurality of signals include first, second and third signals and wherein the controller operates to configure the sensing circuit to apply the first signal to the sensing electrode and to alternately apply the second signal and the third signal to the shield electrode.

15. The system of claim 14, wherein the controller operates to configure the sensing circuit to alternately couple a plurality of impedances between the sensing electrode and the shield electrode;

and wherein the separate measurements used in the calculation of the detection value and force value are taken when the coupling impedances are in different configurations.

16. The system of claim 15, wherein the separate measurements are first, second, third, and fourth current measurements, and wherein the first and second current measurements occur when the second signal is applied to the shield electrode and the third and fourth current measurements occur when the third signal is applied to the shield electrode.

17. The system of claim 16, wherein the first and third current measurements occur when none of the plurality of impedances are coupled between the sensing electrode and shield electrode and the second and fourth current measurements occur when the plurality of impedances are coupled between the sensing electrode and shield electrode.

18. The system of claim 9, further comprising a belt tension sensor operatively coupled to the controller, and wherein the controller is configured to classify the object based on a signal from the belt tension sensor.

19. The system of claim 9, wherein one of the plurality of signals is applied to the shield electrode and wherein the controller is configured to detect a change in a current through the shield electrode resulting from a change in the relative position of the sensing electrode to the shield electrode due to the weight of the object located on the vehicle seat.

20. The system of claim 19, wherein the controller is configured classify the object by calculating a change in impedance between the shield electrode and sensing electrode based on the change in current.

21. The system of claim 20, wherein the sensing electrode is grounded when the controller detects a change in the current through the shield electrode.