Ultrasonic sensor system and method having input capture for echo processing

• US 6,338,028 B1
• Filed: 06/11/1998
• Issued: 01/08/2002
• Est. Priority Date: 06/11/1998
• Status: Expired due to Fees

• Current Assignee: TRW Inc. (Northrop Grumman Corporation)
• Original Assignee: TRW Inc. (Northrop Grumman Corporation)
• Inventors: Shelton, Dennis James, Cooper, Stephen R. W.
• Primary Examiner(s): Assouad, Patrick
• Assistant Examiner(s): TSAI, CAROL S W
• Application Number:
  US09/096,115
• Time in Patent Office: 1,307 Days
• Field of Search: 73/12, 735/97, 736/23, 736/25, 736/26, 736/31, 73/679, 128/660, 180/274, 180/282, 280/734, 280/735, 310/315, 318/286, 324/452, 364/565, 364/562, 364/505, 364/506, 364/550, 364/571.03, 367/6, 367/13, 367/82, 367/97, 367/98, 367/99, 367/108, 367/911, 367/115, 367/910, 367/116, 367/902, 367/127, 367/900, 367/128, 367/140, 701/45, 701/46, 702/39, 702/143, 702/148, 702/159, 702/171
• US Class Current: 702/159
• CPC Class Codes: B60R 21/01526 using piezoelectric elements
• CPC Class Codes: B60R 21/01536 using ultrasonic waves
• CPC Class Codes: G01S 15/04 Systems determining presence of a target
• CPC Class Codes: G01S 7/527 Extracting wanted echo signals Doppler systems G01S15/50

Abstract

An ultrasonic sensor system (36) has a transducer (40) that emits an ultrasonic signal (54), in response to an electrical excitation signal (52) from driver/receiver circuitry (42), and outputs an electrical response signal (58), in response to receipt of a reflected ultrasonic signal (56) from an object, such as a vehicle occupant (14). The response signal (58) is an oscillating signal that has a voltage amplitude indicative of the strength of the reflected ultrasonic signal (56). A receiver circuit (68) of driver/receiver circuitry (42) processes the response signal (58) from said transducer (40) and outputs an analog, non-oscillating signal (60). The analog signal (60) has a voltage amplitude indicative of the voltage of the electrical response signal (58). A comparator (84) of a comparator preprocessor (44) compares the voltage of the analog signal (60) to a predetermined reference voltage (V_REF1) and outputs a digital signal (38). The digital signal (38) is indicative of whether the voltage of the analog signal (60) is greater or less than the reference voltage. A controller (28) processes the digital signal (38) for determining distance between the transducer (40) and the occupant (14). Preferably, the controller (28) controls a protection module (18).

Claims

1. An ultrasonic sensor system comprising:

transducer means for emitting an ultrasonic signal in response to an electrical excitation signal and for outputting an oscillating electrical response signal in response to receipt of a reflected ultrasonic signal from an object, the electrical response signal having an amplitude indicative of the strength of the reflected ultrasonic signal;

receiver means for processing the electrical response signal from said transducer means and for outputting an analog, non-oscillating signal, the analog signal having an amplitude indicative of the amplitude of the electrical response signal;

comparator means for comparing the amplitude of the analog signal to a predetermined amplitude value and for outputting a digital signal having a first digital value when the amplitude of the analog signal is less than the predetermined amplitude value and having a second digital value when the amplitude of the analog signal is greater than the predetermined amplitude value; and

controller means for processing the digital signal to determine distance between said transducer means and the object.

2. A system as set forth in claim 1, wherein the analog signal output by said receiver means has a voltage value that is indicative of the amplitude of the electrical response signal, said comparator means includes a comparator circuit having a first input for receiving the analog signal and a second input for receiving a voltage signal having a reference voltage value that is the predetermined amplitude value, said comparator circuit outputs a signal that has a first voltage value that represents the first digital value when the voltage of the analog signal is less than the reference voltage value and has a second voltage value that represents the second digital value when the voltage of the analog signal is greater than the reference voltage value.

3. A system as set forth in claim 2, wherein said comparator circuit includes means for outputting the signal with a comparatively low voltage for the first voltage value and with a comparatively high voltage for the second voltage value.

4. A system as set forth in claim 1, wherein said receiver means includes means for amplifying and filtering the response signal to process the response signal and for outputting an amplified and filtered oscillating signal.

5. A system as set forth in claim 4, wherein said receiver means includes detector means for detecting an amplitude of the amplified and filtered oscillating signal, and for outputting the analog, non-oscillating signal.

6. A system as set forth in claim 1 including means for processing the analog signal to determine amplitude of the analog signal.

7. A system as set forth in claim 6, wherein said means for processing the analog signal includes an analog-to-digital converter.

8. A system as set forth in claim 1, wherein said controller means includes means for providing a signal to a vehicle occupant protection system having a controllable protection device that is controlled in response to the determination.

9. An ultrasonic sensor system comprising:

transducer means for emitting an ultrasonic signal in response to an electrical excitation signal and for outputting an oscillating electrical response signal in response to receipt of a reflected ultrasonic signal from an object, the electrical response signal having an amplitude indicative of the strength of the reflected ultrasonic signal;

receiver means for processing the electrical response signal from said transducer means and for outputting an analog, non-oscillating signal, the analog signal having an amplitude indicative of the amplitude of the electrical response signal;

comparator means for comparing the amplitude of the analog signal to a predetermined amplitude value and for outputting a digital signal having a first digital value when the amplitude of the analog signal is less than the predetermined amplitude value and having a second digital value when the amplitude of the analog signal is greater than the predetermined amplitude value;

controller means for processing the digital signal to determine distance between said transducer means and the object, and for processing the analog signal to determine amplitude of the analog signal.

10. A system as set forth in claim 9, wherein said controller means includes means for processing the analog signal to determine amplitude of the analog signal only while said digital signal has the second digital value.

11. A system as set forth in claim 9, wherein said controller means includes means for processing the analog signal to determine amplitude of the analog signal only during a predetermined duration after the digital signal changes from the first digital value to the second digital value.

12. A method of ultrasonic sensing comprising:

emitting an ultrasonic signal in response to an electrical excitation signal;

outputting an oscillating electrical response signal in response to receipt of a reflected ultrasonic signal from an object, the electrical response signal having an amplitude indicative of the strength of the reflected ultrasonic signal;

processing the electrical response signal to provide an analog, non-oscillating signal, the analog signal having an amplitude indicative of the amplitude of the electrical response signal;

comparing the amplitude of the analog signal to a predetermined amplitude value;

providing a digital signal having a first digital value when the amplitude of the analog signal is less than the predetermined amplitude value and having a second digital value when the amplitude of the analog signal is greater than the predetermined amplitude value; and

processing the digital signal for determining distance between said transducer means and the object.

13. A method as set forth in claim 12, wherein the analog, non-oscillating signal has a voltage value that is indicative of the amplitude of the electrical response signal, said step of comparing includes receiving the analog signal as a first input and receiving a voltage signal having a reference voltage value that is the predetermined amplitude value as a second input, said step of comparing also includes outputting a signal that has a first voltage value that represents the first digital value when the voltage of the analog signal is less than the reference voltage value and has a second voltage value that represents the second digital value when the voltage of the analog signal is greater than the reference voltage value.

14. A method as set forth in claim 13, wherein said step of comparing includes outputting the signal with a comparatively low voltage for the first voltage value and with a comparatively high voltage for the second voltage value.

15. A method as set forth in claim 12, wherein said step of receiving includes amplifying and filtering the response signal to process the response signal, and outputting an amplified and filtered oscillating signal.

16. A method as set forth in claim 15, wherein said step of receiving includes detecting an amplitude of the amplified and filtered oscillating signal, and outputting the analog, non-oscillating signal indicative of the detected amplitude.

17. A method as set forth in claim 12 including processing the analog signal to determine amplitude of the analog signal.

18. A method as set forth in claim 17, wherein said step of processing the analog signal to determine amplitude includes inputting the analog signal to an analog-to-digital converter.

19. A method as set forth in claim 12, wherein said step of comparing includes comparing the amplitude of the analog signal to a first predetermined amplitude value, said step of providing a digital signal includes providing the digital signal as a first digital signal that has a first digital value when the amplitude of the analog signal is less than first predetermined amplitude value and that has a second digital value when the amplitude of the analog signal is greater than the first predetermined amplitude value, said method includes a plurality of steps of comparing the amplitude of the analog signal to a plurality of predetermined amplitude values, said method includes providing a plurality of digital signals, each digital signal has a first digital value when the amplitude of the analog signal is less than a respective one of the predetermined amplitude values and has a second digital value when the amplitude of the analog signal is greater than the respective one of the predetermined amplitude values, and said method further includes processing the plurality of digital signals for determining amplitude of the analog signal.

20. A method as set forth in claim 12 including providing a signal to a vehicle occupant protection system having a controllable protection device that is controlled in response to the determination.

21. A method of ultrasonic sensing comprising:

emitting an ultrasonic signal in response to an electrical excitation signal;

outputting an oscillating electrical response signal in response to receipt of a reflected ultrasonic signal from an object, the electrical response signal having an amplitude indicative of the strength of the reflected ultrasonic signal;

processing the electrical response signal to provide an analog, non-oscillating signal, the analog signal having an amplitude indicative of the amplitude of the electrical response signal;

comparing the amplitude of the analog signal to a predetermined amplitude value;

providing a digital signal having a first digital value when the amplitude of the analog signal is less than the predetermined amplitude value and having a second digital value when the amplitude of the analog signal is greater than the predetermined amplitude value;

processing the digital signal for determining distance between said transducer means and the object; and

processing the analog signal to determine amplitude of the analog signal.

22. A method as set forth in claim 21, wherein said step of processing the analog signal only occurs when the digital signal has the second value.

23. A method as set forth in claim 21, wherein said step of processing the analog signal only occurs for a predetermined duration after the digital signal changes from the first digital value to the second digital value.

24. An ultrasonic sensor system comprising:

transducer means for emitting an ultrasonic signal in response to an electrical excitation signal and for outputting an oscillating electrical response signal in response to receipt of a reflected ultrasonic signal from an object, the electrical response signal having an amplitude indicative of the strength of the reflected ultrasonic signal;

receiver means for processing the electrical response signal from said transducer means and for outputting an analog, non-oscillating signal, the analog signal having an amplitude indicative of the amplitude of the electrical response signal;

comparator means, including a first comparator means for comparing the amplitude of the analog signal to a first predetermined amplitude value and for outputting a first digital signal having a first digital value when the amplitude of the analog signal is less than the first predetermined amplitude value and having a second digital value when the amplitude of the analog signal is greater than the first predetermined amplitude value;

a second comparator means for comparing the amplitude of the analog signal to a second predetermined amplitude value and for outputting a second digital signal having a first digital value when the amplitude of the analog signal is less than the second predetermined amplitude value and having a second digital value when the amplitude of the analog signal is greater than the second predetermined amplitude value; and

controller means for processing the first digital signal to determine distance between said transducer means and the object and for processing the first and second digital signals to determine amplitude of the analog signal.

25. A system as set forth in claim 24, wherein said system includes a plurality of comparator means, said first comparator means is one of said plurality of comparator means, each of said plurality of comparator means compares the amplitude of the analog signal to a respective predetermined amplitude value and outputs a respective digital signal, each digital signal has a first digital value when the amplitude of the analog signal is less than the respective predetermined amplitude value and has a second digital value when the amplitude of the analog signal is greater than the respective predetermined amplitude value, said controller means also for processing the plurality of digital signals to determine amplitude of the analog signal.