System and Method for Safing and Monitoring a Plurality of Vehicle Sensors

• US 20110187546A1
• Filed: 02/01/2011
• Published: 08/04/2011
• Est. Priority Date: 02/01/2010
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Liberman, Maxim
• Granted Patent: US 8,633,828 B2
• Time in Patent Office: Days
• US Class Current: 340/669
• CPC Class Codes: B60R 2021/01027 Safing sensors
• CPC Class Codes: B60R 2021/01322 comprising variable thresholds, e.g. depending from other collision parameters
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value
• CPC Class Codes: G08B 21/00 Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for

Abstract

A system and method for safing vehicle sensors includes two safety systems, each with a primary sensor for monitoring vehicle motion and activating its corresponding safety system in response to certain vehicle motions. Each sensor may act as a safing sensor for the other in the event that activation of a safety system is indicated by the primary sensor. Each sensor may also monitor the other prior to such an event, to detect a sensor malfunction before that sensor is needed to active a safety system.

Claims

1. A method of operating an airbag safety system and a second safety system on a vehicle, the airbag safety system characterized by an airbag deployment threshold and comprising an airbag and a high-G accelerometer associated with the airbag deployment threshold, the high-G accelerometer specified to measure at least about 20 Gs of acceleration, the second safety system being characterized by a second deployment threshold and comprising a low-G accelerometer associated with a second deployment threshold, the low-G accelerometer specified to measure not more than about 20 Gs, the method comprising:

monitoring the vehicle'"'"'s motion with a first one of the accelerometers to determine whether that accelerometer'"'"'s measurement exceeds its associated deployment threshold;

monitoring the vehicle'"'"'s motion with a second one of the accelerometers to determine whether that accelerometer'"'"'s measurement exceeds an associated plausibility threshold; and

determining whether to deploy at least one of the safety systems, determining being a function of the first accelerometer'"'"'s measurement, the first accelerometer'"'"'s deployment threshold, the second accelerometer'"'"'s measurement, and the plausibility threshold.

2. A method of operating an airbag safety system and a second safety system according to claim 1, wherein:

the first one of the accelerometers is the high-G accelerometer;

the associated deployment threshold is the airbag deployment threshold;

the second one of the accelerometers is the low-G accelerometer; and

the at least one of the safety systems comprises the airbag system.

3. A method of operating an airbag safety system and a second safety system according to claim 1, wherein:

the first one of the accelerometers is the low-G accelerometer;

the associated deployment threshold is the second deployment threshold;

the second one of the accelerometers is the high-G accelerometer; and

the at least one of the safety systems comprises the second safety system.

4. A method of operating an airbag safety system and a second safety system according to claim 2, further comprising:

monitoring the vehicle'"'"'s motion with the low-G accelerometer to determine whether that accelerometer'"'"'s measurement exceeds the second deployment threshold;

monitoring the vehicle'"'"'s motion with the high-G accelerometer to determine whether that accelerometer'"'"'s measurement exceeds an associated second plausibility threshold; and

determining whether to deploy a second one of the safety systems, determining being a function of the second accelerometer'"'"'s measurement, the second accelerometer'"'"'s deployment threshold, the first accelerometer'"'"'s measurement, and the second plausibility threshold.

5. A method of operating an airbag safety system and a second safety system according to claim 3, wherein the second safety system is a vehicle stability control system.

6. A method of operating an airbag safety system and a second safety system according to claim 3, wherein the second safety system is a braking system.

7. A method of operating an airbag safety system and a second safety system according to claim 3, wherein monitoring the vehicle'"'"'s motion with the second one of the accelerometers to determine whether that accelerometer'"'"'s measurement exceeds an associated plausibility threshold comprises monitoring the vehicle'"'"'s motion with the second one of the accelerometers to determine whether that accelerometer'"'"'s measurement exceeds an associated plausibility threshold after the determination that the first accelerometer'"'"'s measurement exceeds its associated deployment threshold.

8. A computer program product for use with a computer processor for operating an airbag safety system and a second safety system on a vehicle, the airbag safety system characterized by an airbag deployment threshold and comprising an airbag and a high-G accelerometer associated with the airbag deployment threshold, the high-G accelerometer specified to measure at least about 20 Gs of acceleration, the second safety system being characterized by a second deployment threshold and comprising a low-G accelerometer associated with a second deployment threshold, the low-G accelerometer specified to measure not more than about 20 Gs, the computer program product comprising a tangible medium having a computer readable program code thereon, the computer readable program code including:

computer code for monitoring the vehicle'"'"'s motion with a first one of the accelerometers to determine whether that accelerometer'"'"'s measurement exceeds its associated deployment threshold;

computer code for monitoring the vehicle'"'"'s motion with a second one of the accelerometers to determine whether that accelerometer'"'"'s measurement exceeds an associated plausibility threshold; and

computer code for determining whether to deploy at least one of the safety systems, determining being a function of the first accelerometer'"'"'s measurement, the first accelerometer'"'"'s deployment threshold, the second accelerometer'"'"'s measurement, and the plausibility threshold.

9. A computer program product according to claim 8, wherein:

the first one of the accelerometers is the high-G accelerometer;

the associated deployment threshold is the airbag deployment threshold;

the second one of the accelerometers is the low-G accelerometer; and

the at least one of the safety systems comprises the airbag system.

10. A computer program product according to claim 8, wherein:

the first one of the accelerometers is the low-G accelerometer;

the associated deployment threshold is the second deployment threshold;

the second one of the accelerometers is the high-G accelerometer; and

the at least one of the safety systems comprises the second safety system.

11. A computer program product according to claim 9, further comprising:

computer code for monitoring the vehicle'"'"'s motion with the low-G accelerometer to determine whether that accelerometer'"'"'s measurement exceeds the second deployment threshold;

computer code for monitoring the vehicle'"'"'s motion with the high-G accelerometer to determine whether that accelerometer'"'"'s measurement exceeds an associated second plausibility threshold; and

computer code for determining whether to deploy at least one of the safety systems, determining being a function of the second accelerometer'"'"'s measurement, the second accelerometer'"'"'s deployment threshold, the first accelerometer'"'"'s measurement, and the second plausibility threshold.

12. A computer program product according to claim 8, wherein the second safety system is a vehicle stability control system.

13. A computer program product according to claim 8, wherein the second safety system is a braking system.

14. A method of operating an airbag safety system and a second safety system according to claim 10 wherein computer code for monitoring the vehicle'"'"'s motion with the second one of the accelerometers to determine whether that accelerometer'"'"'s measurement exceeds an associated plausibility threshold comprises computer code for monitoring the vehicle'"'"'s motion with the second one of the accelerometers to determine whether that accelerometer'"'"'s measurement exceeds an associated plausibility threshold after the determination that the first accelerometer'"'"'s measurement exceeds its associated deployment threshold.

15. A vehicle control apparatus for use with an airbag safety system and a second safety system on a vehicle, the airbag safety system characterized by an airbag deployment threshold and comprising an airbag and a high-G accelerometer associated with the airbag deployment threshold, the high-G accelerometer specified to measure at least 20 Gs of acceleration, the second safety system being characterized by a second deployment threshold and comprising a low-G accelerometer associated with a second deployment threshold, the low-G accelerometer specified to measure not more than 1.5 Gs, the airbag safety systems having an associated airbag plausibility threshold, and the second safety system having an associated second plausibility threshold, the apparatus comprising:

an input for receiving

     1) a first signal from a first one of the accelerometers, and

     2) a second signal from a second one of the accelerometers, the first signal including information relating a measurement of the first one of the accelerometers (“

first measurement”

), the second signal including information relating a measurement of the second one of the accelerometers (“

second measurement”

), the input being one or plural physical inputs;

a comparison circuit configured to determine whether, using the first signal, the first measurement exceeds the deployment threshold of its associated accelerometer,

the comparison circuit also being configured to determine whether, using the second signal, the second measurement exceeds the plausibility threshold of its associated accelerometer, the comparison circuit producing a comparison signal including information relating to the determinations; and

a deployment module operably coupled with the comparison circuit, the deployment module being configured to determine whether to deploy at least one of the safety systems, the deployment module determining whether to deploy as a function of the comparison signal.

16. The apparatus according to claim 15 wherein the first sensor is a high-G accelerometer and the second vehicle sensor is a low-G accelerometer.

17. The apparatus according to claim 15 wherein the first sensor is a low-G acceleration sensor and the second vehicle sensor is a gyroscope.

18. The apparatus according to claim 15 wherein the first safety systems is of a passenger restraint system and the second safety system is a vehicle braking system.

19. A method of operating a first safety system comprising a first sensor having a first sensor output, and a second safety system comprising a second sensor having a second sensor output, the method comprising:

determining whether the first sensor output exceeds a first monitoring threshold;

determining whether the second sensor output exceeds a second monitoring threshold; and

generating a warning signal if one of the first and second sensor outputs fails to exceed its respective monitoring threshold and the other of the first and second sensor outputs exceeds its respective monitoring threshold.

20. A method of monitoring a first safety system and a second safety system according to claim 19, wherein the first sensor is a high-G accelerometer, and the second sensor is a low-G accelerometer.