Occupant detection system

• US 6,302,438 B1
• Filed: 04/19/1999
• Issued: 10/16/2001
• Est. Priority Date: 04/21/1998
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Acquisition, LLC
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Stanley, James G., Stopper, Robert A. Jr.
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): FISCHMANN, BRYAN R
• Application Number:
  US09/294,675
• Time in Patent Office: 911 Days
• Field of Search: 280/735, 180/271, 701/45
• US Class Current: 280/735
• CPC Class Codes: B60R 21/0153 using field detection presence sensors
• CPC Class Codes: B60R 21/0154 in combination with seat heating

Abstract

An occupant detection system (10) for controlling the activation of an air bag inflator (42) incorporates a transmitter/receiver subsystem (16) and a ranging subsystem (20) that respectively measure the distances from a point of reference to the upper seat back (22) and to the region in front of the upper seat back (22). If a normally seated occupant is detected from the difference of the respective distances, then the air bag inflator (42) is enabled. A range/proximity sensing subsystem (14) determines if an occupant is sufficiently close to an air bag inflator (42) to be at risk of injury by deployment thereof, and if so the air bag inflator (42) is disabled.

Claims

1. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto, comprising:

a. a first transmitter for generating and transmitting wave energy;

b. a first receiver for receiving said wave energy and for generating a signal responsive to said wave energy, wherein said wave energy propagates from said first transmitter to said first receiver along a path, the length of said path is responsive to the position of a seat of the vehicle, one of said first transmitter and said first receiver is operatively coupled to a back portion of said seat, and the other of said first transmitter and said first receiver operatively coupled to a fixed interior portion of the vehicle;

c. a ranging sensor for sensing a first region proximate to a forward surface of a back portion of said seat, whereby said ranging sensor is responsive to the presence of a normally seated occupant in said seat;

d. a range/proximity sensor for sensing if an object is within a second region proximate to the safety restraint system, wherein the safety restraint system is disabled responsive to the detection of an object within said second region by said range/proximity sensor; and

e. a controller for controlling the power of the safety restraint system responsive to said signal responsive to said wave energy, and responsive to a signal from said ranging sensor.

2. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said wave energy is selected from the group consisting of acoustic energy, audible acoustic energy, inaudible acoustic energy, ultrasonic acoustic energy, electromagnetic energy, radio frequency electromagnetic energy, light, visible light, invisible light, infrared electromagnetic energy, microwave electromagnetic energy, radar energy, pulsed energy, and continuous wave energy.

3. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said range/proximity sensor is selected from the group consisting of a capacitive sensor, an ultrasonic sensor, a vision system, a radar range finder, a passive infrared sensor, and an optical range finder.

4. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said signal responsive to said wave energy is responsive to a characteristic of said wave energy selected from the group consisting of propagation time, phase, and frequency.

5. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said first transmitter is operatively coupled to a fixed interior portion of the vehicle and said first receiver is operatively coupled to said back portion of said seat.

6. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 5, wherein said ranging sensor determines a range to said forward surface of a back portion of said seat from a signal transmitted by said first transmitter, said controller determines the distance from said first transmitter to said first receiver from said signal responsive to said wave energy, and if the difference between the distance from said first transmitter to said first receiver and said range to said forward surface is less then a threshold, then said controller reduces the power of the safety restraint system.

7. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 6, wherein if a difference between the distance from said first transmitter to said first receiver and said range to said forward surface is less then a threshold, then said controller disables the safety restraint system.

8. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said first transmitter and said ranging sensor share a common transducer.

9. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said ranging sensor comprises said first transmitter and a second receiver.

10. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said ranging sensor comprises a second transmitter and a second receiver.

11. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 10, wherein said ranging sensor depends upon a second wave energy selected from the group consisting of acoustic energy, audible acoustic energy, inaudible acoustic energy, ultrasonic acoustic energy, electromagnetic energy, radio frequency electromagnetic energy, light, visible light, invisible light, infrared electromagnetic energy, microwave electromagnetic energy, radar energy, pulsed energy, and continuous wave energy.

12. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said ranging sensor comprises said first transmitter and said first receiver, wherein said first transmitter and said first receiver are operatively coupled to a fixed interior portion of the vehicle.

13. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 12, wherein said back portion of said seat is adapted so as to provide an identifiable return signal to said first receiver.

14. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said ranging sensor transmits a signal along a path to said first region, and said signal is reflected off an interior portion of the vehicle along said path.

15. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said wave energy propagating along a path between said first transmitter and said first receiver is reflected off an interior portion of the vehicle along said path.

16. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, said controller determines the distance from said first transmitter to said first receiver from said signal responsive to said wave energy and said controller controls the power of the safety restraint system responsive to said distance and to a signal from said ranging sensor.

17. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said range/proximity sensor detects if said object is animate, and the safety restraint system is disabled responsive to the detection of an animate object within said second region by said range/proximity sensor.

18. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto, comprising:

a. a first transmitter for generating and transmitting wave energy, wherein said first transmitter is operatively coupled to a back portion of said seat, and said first transmitter is adapted to transmit said wave energy forwards from said seat;

b. a first receiver for receiving said wave energy and for generating a signal responsive to said wave energy, wherein said wave energy propagates from said first transmitter to said first receiver along a path, and the length of said path is responsive to the position of a seat of the vehicle;

c. a ranging sensor for sensing a first region proximate to a forward surface of said back portion of said seat, whereby said ranging sensor is responsive to the presence of a normally seated occupant in said seat;

d. a range/proximity sensor for sensing if an object is within a second region proximate to the safety restraint system, wherein the safety restraint system is disabled responsive to the detection of an object within said second region by said range/proximity sensor; and

e. a controller for controlling the power of the safety restraint system responsive to said signal responsive to said wave energy, and responsive to a signal from said ranging sensor.

19. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 18, wherein said ranging sensor comprises said first transmitter and a receiver, wherein said receiver of said ranging sensor is selected from the group consisting of said first receiver and a second receiver.

20. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 19, wherein said receiver of said ranging sensor is disposed proximate to said first transmitter so as to receive said wave energy that is reflected by a reflective surface.

21. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 19, wherein said first transmitter and said receiver of said ranging sensor are laterally displaced from one another within said back portion.

22. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 19, wherein said first transmitter and said receiver of said ranging sensor constitute a microwave radar and said wave energy is at least partially reflected by a human body.

23. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 19, wherein said signal responsive to said wave energy is responsive a characteristic of said wave energy selected from the group consisting of propagation time, phase, and frequency.

24. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto, comprising:

a. a first transmitter for transmitting wave energy;

b. a first receiver for receiving said wave energy and for generating a signal responsive to said wave energy, wherein said wave energy propagates from said first transmitter to said first receiver along a path, and the length of said path is responsive to the position of a seat of the vehicle;

c. a ranging sensor for sensing a first region proximate to a forward surface of said back portion of said seat, whereby said ranging sensor is responsive to the presence of a normally seated occupant in said seat;

d. a range/proximity sensor for sensing if an object is within a second region proximate to the safety restraint system, wherein the safety restraint system is disabled responsive to the detection of an object within said second region by said range/proximity sensor; and

e. a controller for controlling the power of the safety restraint system responsive to said signal responsive to said wave energy, and responsive to a signal from said ranging sensor;

f. a proximity sensor operatively coupled to said controller and to said back portion of said seat for sensing an object that is proximate to the front side of a back portion of said seat, wherein said controller controls the power of the safety restraint system responsive to a signal from said proximity sensor.

25. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 24, wherein said ranging sensor comprises said proximity sensor.

26. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 24, wherein if said proximity sensor does not detect an occupant proximate said seat, then said controller disables the safety restraint system.

27. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto, comprising:

a. a first transmitter for transmitting wave energy;

b. a first receiver for receiving said wave energy and for generating a signal responsive to said wave energy, wherein said wave energy propagates from said first transmitter to said first receiver along a path, and the length of said path is responsive to the position of a seat of the vehicle;

c. a ranging sensor for sensing a first region proximate to a forward surface of a back portion of said seat, whereby said ranging sensor is responsive to the presence of a normally seated occupant in said seat;

d. a range/proximity sensor for sensing if an object is within a second region proximate to the safety restraint system, wherein the safety restraint system is disabled responsive to the detection of an object within said second region by said range/proximity sensor; and

e. a controller for controlling the power of the safety restraint system responsive to said signal responsive to said wave energy, and responsive to a signal from said ranging sensor; and

f. a proximity sensor operatively coupled to said controller for sensing an object that is proximate to the front side of a back portion of said seat, wherein said proximity sensor comprises a capacitive sensor located in an upper portion of said back portion of said seat for sensing a dielectric mass proximate to said seat, and said controller controls the power of the safety restraint system responsive to a signal from said proximity sensor.

28. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 27, wherein said capacitive sensor comprises an electrode, and said electrode reflects said wave energy from said first transmitter to said first receiver.

29. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto, comprising:

a. a first transmitter for transmitting wave energy;

b. a first receiver for receiving said wave energy and for generating a signal responsive to said wave energy, wherein said wave energy propagates from said first transmitter to said first receiver along a path, and the length of said path is responsive to the position of a seat of the vehicle;

c. a ranging sensor for sensing a first region proximate to a forward surface of a back portion of said seat, whereby said ranging sensor is responsive to the presence of a normally seated occupant in said seat;

d. a range/proximity sensor for sensing if an object is within a second region proximate to the safety restraint system, wherein the safety restraint system is disabled responsive to the detection of an object within said second region by said range/proximity sensor; and

e. a controller for controlling the power of the safety restraint system responsive to said signal responsive to said wave energy, and responsive to a signal from said ranging sensor, wherein the controller measures the period of time over which said difference between the distance from said first transmitter to said first receiver and said range to said forward surface is less then said threshold, and said power of the safety restraint system is reduced after said period of time exceeds a second threshold.

30. A system for detecting an occupant in a vehicle and for controlling a safety restraint system responsive thereto as recited in claim 29, wherein the safety restraint system is disabled after said period of time exceeds said second threshold.

31. A method of detecting an occupant in a vehicle and for controlling the actuation of a safety restraint system responsive thereto, comprising:

a. measuring a first distance to a back portion of a seat of the vehicle;

b. measuring a second distance to the front surface of said back portion of said seat;

c. detecting if an object is within a region proximate to the safety restraint system, wherein an occupant positioned within said region would be at risk of injury from the safety restraint system;

d. disabling the actuation of the safety restraint system responsive to the detection of an object within said region; and

e. controlling the power of the safety restraint system responsive to the difference between said first and second distance.

32. A method of detecting an occupant in a vehicle and for controlling the actuation of a safety restraint system responsive thereto as recited in claim 31, wherein the power of the safety restraint system is controlled responsive to said first distance and responsive to said second distance.

33. A method of detecting an occupant in a vehicle and for controlling the actuation of a safety restraint system responsive thereto as recited in claim 31, wherein the actuation of the safety restraint system is disabled if said object within said region is a body part.

34. A method of detecting an occupant in a vehicle and for controlling the actuation of a safety restraint system responsive thereto as recited in claim 31, wherein if the difference between said first and second distance is less than a threshold, then reducing the power of the safety restraint system.

35. A method of detecting an occupant in a vehicle and for controlling the actuation of a safety restraint system responsive thereto as recited in claim 32, wherein if the difference between said first and second distance is less than a threshold, then the safety restraint system is disabled.

36. A method of detecting an occupant in a vehicle and of controlling the actuation of a safety restraint system responsive thereto, comprising:

a. measuring a first distance to a back portion of a seat of the vehicle;

b. measuring a second distance to the front surface of said back portion of said seat;

c. detecting if an object is within an region proximate to the safetv restraint system, wherein an occupant positioned within said region would be at risk of injury from the safety restraint system;

d. disabling the actuation of the safety restraint system responsive to the detection of an object within said region;

e. controlling the power of the safety restraint system responsive to the difference between said first and second distance, wherein if the difference between said first and second distance is less than a threshold, then reducing the power of the safety restraint system; and

f. measuring the period of time over which said difference is less than said threshold, wherein the power of the safety restraint system is reduced after said period of time exceeds a second threshold.

37. A method of detecting an occupant in a vehicle and of controlling the actuation of a safety restraint system responsive thereto, comprising:

a. measuring the proximity of an occupant relative to a back portion of a seat of a vehicle;

b. detecting if an object is within a region proximate to the safety restraint system, wherein an occupant positioned within said region would be at risk of injury from the safety restraint system;

c. disabling the actuation of the safety restraint system responsive to the detection of an object within said region;

d. reducing the power of the safety restraint system if an occupant is not proximate to said back portion of said seat; and

e. measuring the period of time over which the occupant is not proximate to said back portion of said seat, wherein the power of the safety restraint system is reduced after said period of time exceeds a second threshold.

38. A method of detecting an occupant in a vehicle and for controlling the actuation of a safety restraint system responsive thereto as recited in claim 37, wherein if the occupant is not proximate to said back portion of said seat, then the safety restraint system is disabled.

39. A method of detecting an occupant in a vehicle and for controlling the actuation of a safety restraint system responsive thereto as recited in claim 37, wherein the power of the safety restraint system is responsive to the proximity of the occupant to said back portion of said seat.

40. A method of detecting an occupant in a vehicle and for controlling the actuation of a safety restraint system responsive thereto as recited in claim 37, wherein the actuation of the safety restraint system is disabled if said object within said region is a body part.

41. A system for sensing the position of a seat of a vehicle, comprising:

a. a set of transmitters and receivers, wherein each said transmitter generates and transmits an associated at least one wave signal to at least one of said receivers, each said receiver generates a signal responsive to said associated at least one wave signal, said set comprises at least one transmitter and at least one receiver, the total number of transmitters and receivers in said set is at least three, a first group comprising at least two like elements of said set are disposed in the seat at distinct locations therein, and a second group comprising at least one element of said set is operatively connected to a fixed interior portion of the vehicle; and

b. a processor for determining a set of distance measurements comprising measurements of the distance from wave signals between each element of said first group of elements of said set and each element of said second group of elements of said set, and for calculating the position of the seat along a seat track and the angle of a back portion of said seat from said set of distance measurements, wherein each of said distance measurements is measured from a characteristic of said associated wave signal.

42. A system for sensing the position of a seat of a vehicle as recited in claim 41, wherein said characteristic of said associated wave signal is selected from the group consisting of propagation time, phase shift, and frequency difference relative to a received signal in comparison with an associated transmitted signal.

43. A system for sensing the position of a seat of a vehicle as recited in claim 41, wherein said wave signal comprises wave energy selected from the group consisting of acoustic energy, audible acoustic energy, inaudible acoustic energy, ultrasonic acoustic energy, electromagnetic energy, radio frequency electromagnetic energy, light, visible light, invisible light, infrared electromagnetic energy, microwave electromagnetic energy, radar energy, pulsed energy, and continuous wave energy.

44. A system for sensing the position of a seat of a vehicle as recited in claim 41, wherein said set of transmitters and receivers comprises a first transmitter paired with a first receiver and a second transmitter paired with a second receiver, wherein said first transmitter and said first receiver are operative between a first fixed portion of the vehicle and a first point in the seat, and said second transmitter and said second receiver are operative between a second fixed portion of the vehicle and a second point in the seat.

45. A system for sensing the position of a seat of a vehicle as recited in claim 44, wherein said first point in the seat is in a back portion of the seat and said second point in the seat is in said back portion of the seat at a distinct location from said first point in the seat.

46. A system for sensing the position of a seat of a vehicle as recited in claim 44, wherein said first point in the seat is in a back portion of the seat and said second point in the seat is in a base portion of the seat.

47. A system for sensing the position of a seat of a vehicle as recited in claim 44, wherein said first fixed portion of the vehicle is the same as said second fixed portion of the vehicle.

48. A system for sensing the position of a seat of a vehicle as recited in claim 44, wherein said processor communicates said position of the seat along a seat track and said angle of said back portion of said seat to another system in the vehicle so as to enable said another system to adapt to the position of the seat.

49. A system for sensing the position of a seat of a vehicle, comprising:

a. a set of transmitters and receivers, wherein each said transmitter transmits an associated at least one wave signal to at least one of said receivers, said set comprises at least one transmitter and at least one receiver, the total number of transmitters and receivers in said set is at least three, a first group comprising at least two like elements of said set are disposed in the seat at distinct locations therein, a second group comprising at least one element of said set is operatively connected to a fixed interior portion of the vehicle, said set of transmitters and receivers comprises a first transmitter paired with a first receiver and a second transmitter paired with a second receiver, said first transmitter and said first receiver are operative between a first fixed portion of the vehicle and a first point in the seat, said second transmitter and said second receiver are operative between a second fixed portion of the vehicle and a second point in the seat, said first fixed portion of the vehicle is rearwards of a back portion of the seat and said second fixed portion of the vehicle is forwards of said back portion of the seat; and

b. a processor for determining a set of distance measurements comprising measurements of the distance from wave signals between each element of said first group of elements of said set and each element of said second group of elements of said set, and for calculating the position of the seat along a seat track and the angle of a back portion of said seat from said set of distance measurements, wherein each of said distance measurements is measured from a characteristic of said associated wave signal.

50. A method of sensing the position of a seat of a vehicle, comprising:

a. measuring a first distance from a first fixed point of the vehicle interior to a first point on the seat between a first transmitter and a first receiver, wherein one of said transmitter and said receiver is located in the seat, said first transmitter generates and transmits a first wave signal to said first receiver, said first receiver generates a first signal responsive to said first wave signal, and said first distance is measured responsive to said first signal from a characteristic of said first wave signal selected from the group consisting of propagation time, phase shift, and frequency difference relative to a received signal in comparison with an associated transmitted signal;

b. measuring a second distance from a second fixed point of the vehicle interior to a second point on the seat between a second transmitter and a second receiver, wherein one of said transmitter and said receiver is located in the seat, said second transmitter generates and transmits a second wave signal to said second receiver, said second receiver generates a second signal responsive to said second wave signal, and said second distance is measured responsive to said second signal from a characteristic of said second wave signal selected from the group consisting of propagation time, phase shift, and frequency difference relative to a received signal in comparison with an associated transmitted signal; and

c. calculating the position of the seat along a seat track and the angle of a back portion of the seat from said first and second distance measurements.

51. A method of sensing the position of a seat of a vehicle as recited in claim 50, wherein said first fixed point of the vehicle interior is at a different location from said second fixed point of the vehicle.

52. A method of sensing the position of a seat of a vehicle, comprising:

a. measuring a first distance from a first fixed point of the vehicle interior to a first point on the seat between a first transmitter and a first receiver, wherein one of said transmitter and said receiver is located in the seat, said first transmitter transmits a first wave signal to said first receiver, and said first distance is measured from a characteristic of said first wave signal selected from the group consisting of propagation time, phase shift, and frequency difference relative to a received signal in comparison with an associated transmitted signal;

b. measuring a second distance from a second fixed point of the vehicle interior to a second point on the seat between a second transmitter and a second receiver, wherein one of said transmitter and said receiver is located in the seat, said second transmitter transmits a second wave signal to said second receiver, and said second distance is measured from a characteristic of said second wave signal selected from the group consisting of propagation time, phase shift, and frequency difference relative to a received signal in comparison with an associated transmitted signal; and

c. calculating the position of the seat along a seat track and the angle of a back portion of the seat from said first and second distance measurements, wherein the operation of calculating the position of the seat along a seat track and the angle of a back portion of said seat from said first and second distance measurements comprises;

i. for each position of the seat along said seat track, storing a first characteristic in memory, wherein said first characteristic comprises said first distance as a function of said angle of said back portion of the seat;

ii. for each position of the seat along said seat track, storing a second characteristic in memory, wherein said second characteristic comprises said second distance as a function of said angle of said back portion of the seat;

iii. calculating a cost function using said first and second characteristic functions from said first and second distance measurements at a plurality of positions of the seat along said seat track;

iv. finding a position of the seat along said seat track that minimizes said cost function; and

v. finding an angle of said back portion of said seat from said position of the seat along said seat track that minimizes said cost function, one of said distance measurements, and a corresponding one of said characteristic functions.