Apparatus and method for determining distance utilizing a continuously variable rate sensor for vehicle occupant position sensing

• US 6,550,806 B1
• Filed: 04/19/2000
• Issued: 04/22/2003
• Est. Priority Date: 04/19/2000
• Status: Expired due to Fees

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Cooper, Stephen R. W., Gillis, Edward J.
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): PHAN, HAU VAN
• Application Number:
  US09/552,328
• Time in Patent Office: 1,098 Days
• Field of Search: 280/735, 280/731, 280/730.2, 280/736, 280/739, 180/282, 180/272, 180/273, 701/45, 340/436, 340/438
• US Class Current: 280/735
• CPC Class Codes: B60R 21/01536 using ultrasonic waves
• CPC Class Codes: G01S 15/105 using irregular pulse repetition frequency

Abstract

An apparatus (42) determines distance to an object (12), and preferably the object is a vehicle occupant. A sensor (40) of the apparatus (42) senses distance to the occupant (12) at a sensor rate. A rate determination function portion (74) of a controller (30) varies the sensor rate as a function of the sensed distance. Preferably, the sensor (40) emits signals (46) at the sensor rate toward the occupant (12) and receives reflected signals from the occupant. A time between emission of a signal and reception of an associated reflected signal is used to determine a distance to the occupant (12) at a distance determination function portion (54) of the controller (30). Change in the rate of signal emission is in response to each change in determined distance and is continuous with the change in determined distance. Preferably, the apparatus is part of an occupant protection system (10) for a vehicle (16). A portion (60) of the controller (30) makes determinations regarding control of a protection device (18) of the system (10) using the sensed distance.

Claims

1. An apparatus for determining distance to an object, said apparatus comprising:

sensor means for sensing distance to the object from the sensor means at a sensor rate; and

variation means for continuously varying the sensor rate of the sensor means, the sensor rate being dependent only upon the sensed distance and varying inversely to the sensed distance.

2. An apparatus as set forth in claim 1, wherein said variation means includes means for varying the sensor rate as a linear function of the sensed distance.

3. An apparatus as set forth in claim 1, wherein said sensor means includes an ultrasound sensor, said sensor rate is a rate at which the ultrasound sensor outputs ultrasonic pings.

4. An apparatus as set forth in claim 1, wherein said apparatus is part of a vehicle occupant protection system that has an actuatable occupant protection device, said sensor means including means for sensing a distance to an occupant, said apparatus including means for outputting a signal indicative of the sensed distance to a portion of said protection system that utilizes the sensed distance to control said occupant protection device.

5. An apparatus as set forth in claim 4, wherein said occupant protection system device includes an air bag module.

6. An apparatus for determining distance to an object, said apparatus comprising:

means for emitting signals at a rate toward the object, the object reflecting the signals;

means for receiving reflected signals from the object;

means for determining a time between emission of a signal and reception of an associated reflected signal;

means for determining a distance to the object using the determined time; and

means for changing the rate of signal emission in response to each change in determined distance, the rate of signal emission changing dependent upon only the determined distance.

7. An apparatus as set forth in claim 6, wherein said means for changing the rate includes means for changing the rate such that a reflected signal from the object received at said means for receiving occurs prior to said means for emitting a subsequent signal.

8. An apparatus as set forth in claim 6, wherein said means for changing the rate includes means for changing the rate in an inverse proportion to the determined distance.

9. An apparatus as set forth in claim 6, wherein said means for changing the rate includes means for changing the rate as a linear function of the determined distance.

10. An apparatus as set forth in claim 6, wherein said apparatus is part of a vehicle occupant protection system that has an actuatable occupant protection device, the determined distance is a distance to an occupant, said apparatus including means for outputting a signal indicative of the determined distance to a portion of said protection system that utilizes the determined distance to control said occupant protection device.

11. An apparatus as set forth in claim 10, wherein said occupant protection system device includes an air bag module.

12. A method for determining distance to an object, said method comprising:

sensing distance to the object at a sensor rate; and

varying the sensor rate as a function of only the sensed distance, the sensor rate varying inversely to the sensed distance.

13. A method as set forth in claim 12, wherein said step of sensing includes emitting signals at the sensor rate toward the object, receiving reflected signals from the object, and determining a time between emission of a signal and reception of an associated reflected signal, and said step of varying includes changing the sensor rate in response to each change in determined distance.

14. A method as set forth in claim 13, including providing a signal indicative of the determined distance for control of an occupant protection device.

15. A method for controlling an occupant protection device in an occupant protection system for a vehicle, said method comprising:

sensing a distance to a vehicle occupant at a sensor rate;

making determinations regarding control of the protection device using the sensed distance; and

varying the sensor rate inversely to only the sensed distance.

16. An apparatus for determining distance to an object, comprising:

sensor means for emitting signals at a sensor rate toward the object, the object reflecting the signals;

means for receiving reflected signals from the object;

means for determining a time between emission of a signal and reception of an associated reflected signal;

means for determining a distance to the object using the determined time;

means for determining the sensor rate in response to each change in the determined distance; and

means for changing the rate of signal emission in response to the sensor rate determination.

17. An apparatus as set forth in claim 16 wherein said means for determining the sensor rate in response to each change in the determined distance includes means for determining the sensor rate as a function of the determined distance.

18. An apparatus as set forth in claim 16 wherein said means for determining the sensor rate in response to each change in the determined distance includes:

means for calculating the sensor rate with an algorithm using a value that corresponds to the determined distance.

19. An apparatus as set forth in claim 16 wherein said means for determining the sensor rate in response to each change in the determined distance includes:

means for using a value that corresponds to the determined distance to determine a memory address in a memory;

means for retrieving a stored sensor rate value from the memory; and

means for setting the sensor rate in response to the sensor rate value.