OCCUPANT SENSOR AND METHOD FOR SEAT BELT OR OTHER MONITORING

• US 20070194900A1
• Filed: 02/19/2007
• Published: 08/23/2007
• Est. Priority Date: 02/21/2006
• Status: Active Grant

• Current Assignee: Nidec Elesys Americas Corporation (Nidec Corporation)
• Original Assignee: Elesys North America Incorporated (Nidec Corporation)
• Inventors: Hawkins, Eric T., Miyamori, Masahiro
• Granted Patent: US 7,791,476 B2
• Time in Patent Office: Days
• US Class Current: 340/457.1
• 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 2/0034 in, under or on the seat cover
• 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 2210/12 Capacitive; Electric field
• CPC Class Codes: B60N 2230/10 Wired data transmission
• CPC Class Codes: B60N 2230/30 Signal processing of sensor data
• CPC Class Codes: B60R 2022/4816 for sensing locking of buckle
• CPC Class Codes: B60R 2022/4866 Displaying or indicating arrangements thereof
• CPC Class Codes: B60R 21/0152 using strain gauges
• CPC Class Codes: B60R 21/01532 using electric or capacitive field sensors
• CPC Class Codes: B60R 22/48 Control systems, alarms, or interlock systems, for the correct application of the belt or harness

Abstract

The change in voltage or current of the antenna is measured by the time to reach a particular voltage level. Using either charging and/or discharging, the times to reach two or more different levels of the total charge are measured. By providing sensor electronics with each sensor or antenna, a more versatile system may be provided. The sensors and associated electronics communicate using a bus or other communication path to a processor. The processor determines an occupant state based on the received sensor information. Different numbers of sensors may be used with the same system.

Claims

1. A sensor system for seat belt monitoring or occupant detection, the sensor system comprising:

a first antenna positioned adjacent to an occupant space;

a first circuit connected with the first antenna, the first circuit operable to sense with the first antenna;

a processor operable to determine an occupant state as a function of first information output by the first circuit; and

a communications path connected with the first circuit and the processor and operable to carry the first information from the first circuit to the processor, the processor spaced from the first circuit.

2. The sensor system of claim 1 wherein the first antenna comprises a conductor on flexible circuit material.

3. The sensor system of claim 1 wherein the first circuit comprises a comparator operable to compare a voltage of the first antenna with a reference voltage.

4. The sensor system of claim 3 further comprising a resistor network operable to generate the reference voltage.

5. The sensor system of claim 4 wherein at least one resistor is switchably grounded, connected to a high voltage, or connected to a high impedance.

6. The sensor system of claim 1 wherein the processor connects with an air bag controller.

7. The sensor system of claim 1 wherein the first circuit is operable to change a voltage or current applied to the first antenna and operable to detect a response of the first antenna to the change as a function of timing.

8. The sensor system of claim 1 wherein the communications path comprises a communications bus.

9. The sensor system of claim 8 wherein the processor comprises a bus controller and the first circuit comprises a digital output operable with the bus controller.

10. The sensor system of claim 1 further comprising at least a second antenna, and at least a second circuit, the second circuit connectable with the communications path, the communications path and the processor configurable to operate with different numbers of the first and second circuits.

11. The sensor system of claim 10 wherein the first and second antennas are adjacent the occupant space for a same occupant in a vehicle.

29. The sensor system of claim 1 wherein the first circuit comprises first and second selectable resistance circuits, the first information including measurements associated with different combinations of the first and second selectable resistance circuits, and wherein the processor is operable to determine resistive and capacitive components as a function of the first information.

12. A method for seat belt monitoring or occupant detection, the method comprising:

providing one or more sensor modules, each sensor module comprising at least one antenna and at least one measurement circuit, each sensor module operable to detect responsive to any occupant in a vehicle;

providing for a common processor operable to determine an occupancy state as a function of the detections from the sensor modules; and

arranging for communications from each of the sensor modules to the common processor, the common processor operable with different numbers of the sensor modules.

13. The method of claim 12 wherein arranging comprises providing a bus between the sensor modules and the common processor.

14. The method of claim 12 further comprising:

each sensor module operating autonomously from each other and sharing a communications path with the common processor.

15. A sensor system for seat belt monitoring or occupant detection, the sensor system comprising:

a first antenna positioned adjacent to an occupant space; and

a first circuit connected with the first antenna, the first circuit operable to change a voltage or current applied to the first antenna and operable to detect a response of the first antenna to the change as a function of timing.

16. The sensor system of claim 15 wherein the first circuit comprises a comparator operable to compare the response of the first antenna with a reference.

17. The sensor system of claim 16 wherein the first circuit comprises a resistor network operable to generate the reference.

18. The sensor system of claim 17 wherein at least one resistor is switchably connectable to at least two sources from the group of:

low voltage, rounded, high voltage, or a high impedance, the reference responsive to a currently connected source.

19. The sensor system of claim 15 wherein the first circuit comprises a counter operable to count until the response is at a reference, the timing being a function of the count.

20. The sensor system of claim 15 wherein the first circuit is operable to detect a first time to a first reference for a first response and a second time to a second reference for a second response.

21. The sensor system of claim 20 further comprising:

a processor operable to determine an occupant state as a function of the timing; and

a bus connected with the first circuit and the processor and operable to communicate the timing from the first circuit to the processor.

22. A method for seat belt monitoring or occupant detection, the method comprising:

charging or discharging an antenna adjacent to an occupant space;

timing the charging or discharging relative to a reference level; and

determining an occupant state of the occupant space as a function of the timing.

23. The method of claim 22 wherein timing comprises comparing a voltage or current of the antenna to a reference voltage or current.

24. The method of claim 22 wherein timing comprises counting a number of cycles until the charging or discharging reaches the reference level.

25. The method of claim 22 further comprising generating the reference level and generating another reference level, wherein determining comprises determining as a function of the timing with respect to the reference level and other timing with respect to the other reference level.

26. The method of claim 25 wherein generating the reference level and the other reference level comprise connecting a reference circuit to at least two sources, respectively, from the group of:

low voltage, rounded, high voltage, or a high impedance.

27. The method of claim 22 further comprising timing the charging or discharging relative to another reference level different than the reference level, wherein determining comprises determining as a function of both timings.

28. The method of claim 22 further comprising:

separating capacitive and resistive components of the timing;

wherein determining the occupant state comprises determining as a function of the resistive component.