Communications: electrical – Land vehicle alarms or indicators – Of collision or contact with external object
Reexamination Certificate
2000-02-26
2001-12-11
Pope, Daryl (Department: 2736)
Communications: electrical
Land vehicle alarms or indicators
Of collision or contact with external object
C340S435000, C340S903000, C180S282000, C280S735000, C701S301000
Reexamination Certificate
active
06329910
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a vehicle impact detection apparatus and method.
1. Background of the Invention
Vehicle safety has been a major issue since the 1960's and numerous measures have been introduced to improve the safety of vehicles. The focus of vehicle safety improvements has been to lessen the risk of serious injury to vehicle occupants. Measures such as the compulsory wearing of seatbelts, use of airbag systems, provision of crumple zones and the existence of a “survival cell” in a vehicle has much improved the chance of a vehicle occupant escaping an accident without serious injury. Nevertheless, concern has recently been expressed regarding the safety of vehicles in relation to pedestrians and other vulnerable road users, such as cyclists or motorcyclists.
2. Discussion of the Prior Art
A sensor preferably determines the location on the vehicle that is impacted by an object and the type of object being impacted. In such a case, the sensor may be arranged to send a firing signal in the event of an impact with a vulnerable road user and not send a firing signal in the event of an impact with a less vulnerable object, for example another vehicle.
The sensor is preferably a magnetostrictive sensor. Magnetostrictive sensors have been proposed for sensing vehicle impacts to initiate vehicle occupant protection systems. U.S. Pat. No. 5,580,084 relates to a system for controlling actuation of a vehicle safety device comprising a magnetostrictive sensor connected via a signal processor to the safety device. U.S. Pat. No. 5,767,766 relates to an apparatus for monitoring the vehicular impact using magnetostrictive sensors.
SUMMARY OF THE INVENTION
A sensor may be arranged adjacent a part of the body of a vehicle. The body part may include a stress-conducting member. The sensor may be arranged adjacent the stress-conducting member. The stress-conducting member is preferably elongate. Most preferably the stress-conducting member is arranged to conduct stress waves along its length. In that way, stress waves are conducted from the point of impact directly to the sensor without dissipating into the vehicle body. The stress-conducting member may be ferromagnetic. Alternatively, part of the body adjacent the sensor may be rendered ferromagnetic.
The stress-conducting member is most preferably included in a bumper or door of the vehicle. Where the bumper or door is made from a plastic material, the stress-conducting member may be insert molded into the bumper. The stress-conducting member may comprise a strengthening bar in the bumper or door. Most preferably the strengthening bar is enclosed within the lower air dam of the bumper.
The safety device may be an airbag arranged to deploy externally of the vehicle so as to cushion the impact of the object against the vehicle. The safety device may comprise means to deploy the hood of the vehicle upwardly from its normal position.
Data acquired from magnetostrictive sensors can be used to determine crash severity and crash characteristics.
According to a third aspect of the invention there is provided a vehicle impact detection apparatus comprising a magnetostrictive sensor, a stress-conducting member arranged on or forming part of the body of the vehicle, the sensor being arranged to sense stress waves in the stress-conducting member and provide a signal to signal analysis means which analyzes the signal from the sensor to determine information about the impact.
The vehicle impact detection apparatus may be arranged to determine the type of object impacted by the vehicle. In particular, the vehicle impact detection apparatus may determine whether the impacted object is a vulnerable road user.
Alternatively, the vehicle impact detection apparatus may determine the characteristics of the crash to enable decisions to be taken regarding vehicle occupant protection systems. The information received from a magnetostrictive sensor is data rich and the type of crash can be identified by analyzing that data. That enables a control unit to determine which, if any of the vehicle safety systems should be deployed. For example, in a side impact only the side airbags may be deployed or depending upon the crash characteristics front and side airbags may need to be deployed. In another embodiment the detection apparatus supplies data to identify whether the impacted object is a “vulnerable road user” to determine whether external vehicle safety systems of the type described above should be deployed.
The stress-conducting member may be a body part of the vehicle. Alternatively, the stress-conducting member may comprise a separate strain element.
The stress-conducting member is preferably elongate so that stress waves caused by impact with an object are conducted to the sensor without significant dissipation thereof. The nature of the elongate stress-conducting member provides a characteristic response to impacts of similar type dependent on where the impact occurs along the stress-conducting member. As mentioned above the stress conducting member may be ferromagnetic or part of the body of vehicle adjacent the sensor may be ferromagnetic.
The separate strain element may be located in a bumper or door of the vehicle. Where the bumper or door is made from a plastic material, the strain element may be insert molded into the bumper or door. The strain element preferably comprises a strengthening bar, most preferably in the lower air dam of the bumper structure.
According to another aspect of the invention there is provided a method of analyzing an impact of a vehicle comprising the steps of providing a magnetostrictive sensor on a vehicle providing a stress-conducting member arranged on or forming part of a vehicle, providing signal analysis means, arranging the sensor adjacent the stress-conducting member, sensing stress waves in the stress-conducting member, providing a signal to the signal analysis means, analyzing the signal to determine information about the impact.
Preferably the signal analysis means comprises spectral analysis means. In that way, the frequency spectrum of the signal can be analyzed and the type of crash, location of crash or type of object impacted can be determined. The location of the impact along the stress-conducting member can be determined by analysis of the frequency spectrum. At the point of impact the frequency spectrum comprises a high proportion of high frequency waves. As the waves move along the stress-conducting member the waves are attenuated into lower frequency waves. Thus the frequency spectrum further away from the impact point includes a higher proportion of lower frequency waves. Accordingly it is possible to assess the distance along the stress-conducting member that the wave energy has traveled to reach the sensor.
Additionally, analysis of wave amplitude and spectrum can give information about the characteristics of the crash including revealing data about the type of object impacted.
REFERENCES:
patent: 4249632 (1981-02-01), Lucchini et al.
patent: 5580084 (1996-12-01), Gioutsos
patent: 5739757 (1998-04-01), Gioutsos
patent: 5767766 (1998-06-01), Kwun
patent: 6031449 (2000-02-01), Laporte et al.
patent: WO 9718108 (1997-05-01), None
Breed Automotive Technology Inc.
Drayer Lonnie
Pope Daryl
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