The present invention relates generally to a vehicle occupant safety system and more particularly to a vehicle occupant active restraint system that determines contact with an out-of-position occupant during activation and consequently reduces activation force to reduce the possibility of injury to the out-of-position occupant. Generally, an occupant who is positioned relative to the active restraint in a manner such that full activation of the restraint may cause injury is considered an “out-of-position” occupant.
Many known systems have been developed for determining the position of an occupant within a motor vehicle for the purpose of determining whether and with how much force to activate an active safety restraint such as an airbag. For example, some known systems determine if an occupant is sitting too close to an airbag and may consequently determine not to fire the airbag in the event of an accident or may determine to fire the airbag with less force.
U.S. Pat. No. 6,129,379, assigned to the assignee of the present invention, discloses an airbag module with a plurality of strips attached to the airbag. During the deployment of the airbag, the speed with which the strips are extended can be evaluated to determine the speed of deployment of the airbag.
The present invention provides an algorithm for evaluating information from sensors interacting with strips that are extended during activation of the airbag.
In one embodiment, each strip includes an alternating pattern that generates a frequency in a sensor through which the strip passes during deployment. The frequency generated is based upon the speed with which the strip passes by the sensor and, in turn, the speed of deployment of the airbag. A controller evaluates the frequency and the changes in frequency over time during deployment. Depending upon the specific configuration of the system and the specific vehicle, a decrease in the speed of deployment of the airbag may be indicated by a decrease in the frequency of the signal. A decrease in speed of deployment may indicate that the airbag is in contact with an occupant.
Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
A vehicle occupant safety system 20 is shown schematically in
Generally, the controller 30, based upon information from the crash determination module 28, determines whether to fire the airbag module 24, when to fire the airbag module 24 and with how much force to fire the airbag module 24 (in the case of a variable force inflator 26). The vent 27 in the airbag inflator 26 permits the controller 30 to cease inflation of the airbag 24 at any moment based upon a determination by the controller 30 that the airbag 24 has contacted an occupant and/or an out-of-position occupant.
A plurality of strips 34 (three shown as 34a, 34b, 34c and 34d and referred to generically as 34), each including a pattern, such as light and dark areas, are connected to various points on the airbag 24. The pattern may alternatively comprise holes or serrations, electrical connections, magnetic patterns or any optical, mechanical or magnetic pattern. The pattern is preferably regular, with equal black and white areas, but the pattern could comprise unequal black and white areas, and could have a spacing that varies over the length of the strip 34.
The pattern of each strip 34a, b, c, d passes through a sensor 36a, b, c, d respectively, to generate a signal that varies based upon the speed that the strip 34 passes through the sensor 36. If the pattern is a regular pattern of light and dark areas, for example, the sensors 36 would be optical sensors 36 and the signals would each vary in frequency based upon the speed of the respective strip 34. In the preferred embodiment, the sensors 36 are sampled at a rate preferably at least twice the highest frequency expected to be experienced. The particular technique for evaluating the signals from the sensors 36 will be described in more detail below.
In the present invention, the controller 30 monitors the velocity of the airbag 24 during deployment by monitoring the signals from the sensors 36. In the present example, the controller 30 monitors the frequency of the outputs of the sensors 36. In the event that the controller 30 determines that a change in velocity (or lack of change in velocity) indicates that an out-of-position occupant has been impacted, the controller 30 activates the vent 27 on the airbag inflator 26, which releases the expanding gas from the inflator 26 outside the airbag 24, thus ceasing inflation or decreasing the inflation force of the airbag 24. The controller 30 determines that the airbag 24 has impacted an occupant by performing a time frequency analysis, e.g. comparing the velocity (i e., the frequency) to a threshold that varies over time from the initiation of the airbag 24 inflation.
Preferably, the controller 30 analyzes the signal from each sensor 36 for each strip 34 by applying a fast Walsh Transform to the raw data of
The present invention reduces the possibility of injury to the out-of-position occupant by determining the impact of the airbag 24 with the occupant and activating the vent 27 on the airbag inflator 26 without the need for external occupant position sensors.
In an alternate technique of the present invention, the controller 30 counts the number of samples of the output of each of the sensors 36 that are of each of the pattern outputs (i.e. black and white, or hole and no-hole) before it switches to the other of the pattern outputs. For example, the controller 30 might sample 25 black outputs, then 23 white outputs, then 22 black outputs, etc. In this case, the number of samples of each of the pattern outputs will be inversely proportional to the velocity of the strip 34 and the airbag 24 deployment velocity.
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In accordance with the provisions of the patent statutes and jurisprudence, exemplary configurations described above are considered to represent a preferred embodiment of the invention. However, it should be noted that the invention could be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.
This application is a Divisional of application Ser. No. 10/388,428, filed Mar. 17, 2003, Pat. No. 6,789,818, which claims priority to U.S. Provisional Application Ser. No. 60/422,699, filed Oct. 31, 2002.
Number | Name | Date | Kind |
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5957490 | Sinnhuber | Sep 1999 | A |
6129379 | Specht | Oct 2000 | A |
6308983 | Sinnhuber | Oct 2001 | B1 |
Number | Date | Country |
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19611384 | Sep 1997 | DE |
Number | Date | Country | |
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20040232673 A1 | Nov 2004 | US |
Number | Date | Country | |
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60422699 | Oct 2002 | US |
Number | Date | Country | |
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Parent | 10388428 | Mar 2003 | US |
Child | 10862143 | US |