Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
2003-09-23
2004-12-14
Jeanglaude, Gertrude A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C701S301000, C340S436000, C340S903000, C180S271000
Reexamination Certificate
active
06832145
ABSTRACT:
BACKGROUND OF THE INVENTION
1) Field of the Invention
The present invention relates to a pedestrian collision protection system for a vehicle, and to a collision site (position) detecting apparatus suitable for use in the pedestrian collision protection system.
2) Description of the Related Art
So far, there has been proposed a pedestrian collision protection apparatus for a vehicle in which a pedestrian collision detecting apparatus (which will hereinafter be referred to equally as a “bumper sensor”) is placed on a front bumper of a vehicle to detect a collision with a pedestrian so that, if this detecting apparatus has detected a collision of the vehicle with a pedestrian when the vehicle is in a traveling condition, an air bag provided at an upper surface of a front portion of the vehicle, or the like, is activated to alleviate the impact to be made on the pedestrian who collapses onto the upper surface of the front portion of the vehicle.
As one example of the pedestrian collision protection system, Japanese Patent No. 3212841 discloses a technique in which, in addition to the aforesaid bumper sensor (collision detecting element), a laser light emitting/receiving device (collision site detecting element) is provided to monitor a space above a front portion of a vehicle and an upper surface of the vehicle front portion is divided into a plurality of areas and an air bag (pedestrian protecting element) is provided in each of the areas.
The laser light emitting/receiving device is made to emit laser beams from right and left sides of a front portion of a vehicle toward a pedestrian collapsing onto the space above the vehicle front portion to, on the basis of reflected light therefrom, make a decision as to whether the pedestrian falls into the right side or left side of the upper surface of the vehicle front portion. This enables only an air bag in the falling-into-side to be spread, thus achieving the size reduction of the air bag.
The concrete examples of the bumper sensor (collision detecting element) are disclosed in Japanese Patent Laid-Open Nos. HEI 8-216826 and HEI 11-310095. The bumper sensor disclosed in the former document is constructed in a manner such that electrodes are placed on both sides of an electric conductive rubber containing a metallic conductive fine-grain and is formed into an elongated configuration to securely detect a collision of a pedestrian even where the pedestrian collides in a front bumper. The bumper sensor disclosed in the latter document includes a pressure sensor for sensing an internal pressure of an elastic tube filled with a gas and is made to detect a collision against a pedestrian on the basis of a rise of the internal pressure of the elastic tube.
The pedestrian collision protection system disclosed in Japanese Patent No. 3212841 is capable of making a decision on a site (position in right- and left-hand directions) of a collision against a pedestrian and, hence, enables the size reduction of an air bag to be spread. In consequence, it is possible to quickly operate an impact buffering device, such as spreading an air bag, with a less application force, which is advantageous in practical use.
However, this pedestrian collision protection system can detect a collision itself through the use of the bumper sensor but creating problems in that 1) difficulty is encountered in making a decision on a collision site with a pedestrian until one of or both the right- and left-side laser light emitting/receiving devices for the pedestrian collision site detection detects the pedestrian falling into a space above a front portion of the vehicle and, hence, the time from when the collision site is confirmed until the spreading of an air bag becomes short, 2) if intensive sunlight is incident on the light-receiving portion of the laser light emitting/receiving device, the incident light quantity exceeds its input dynamic range to make it difficult to detect a pedestrian forming an object of optical reflection, 3) the equipment cost becomes high because a pair of laser light emitting/receiving devices are required for monitoring the object of optical reflection above the vehicle front portion, and 4) the detection accuracy drops due to dirt and damage to lens surfaces. For these reasons, it is difficult to put it in practical use.
The bumper sensor disclosed in Japanese Paten Laid-Open No. HEI 8-216826 has a structure in which an electric conductive rubber containing a metallic conductive fine-grain is interposed between a pair of electrodes and is made to detect a collision against a pedestrian through the use of the phenomenon in which the electric resistance value between both the electrodes lowers when the electric conductive rubber is compressed by the collision. However, since there is a need for the bumper sensor to detect a collision against a pedestrian irrespective of the collision position in lateral directions of the vehicle, the total electrode area becomes naturally large. Meanwhile, in the case of such a conductive grain dispersed rubber, difficulty is encountered in easily reducing the direct-current leakage at non-collision. Considering the large electrode area, the direct-current loss becomes considerably large.
Moreover, in the case of the bumper sensor disclosed in Japanese Paten Laid-Open No. HEI 11-310095, difficulty is experienced in maintaining the internal pressure of the elastic tube, and a delay in activation of an air bag occurs due to a delay in detection stemming from a pressure propagation time in the interior of the tube.
Accordingly, the conventional pedestrian collision protection systems require, in addition to the bumper sensor (a sensor fixedly secured onto a front bumper) for detecting a collision against a pedestrian to recognize a collision site in right- and left-hand directions (lateral directions) of a vehicle, the additional use of a sensor for specifying the collision site in the lateral directions and, hence, there is a need to considerably reduce the manufacturing cost and solve the detection delay problem.
Meanwhile, in the case of conventional collision detecting apparatus, even if the detection of a collision is feasible, difficulty is encountered in distinguishing between a pedestrian and an object of collision other than the pedestrian. In order to avoid useless activation of a pedestrian protecting device such as an air bag, it is preferable to activate the pedestrian protecting device after the confirmation that the object of collision is a pedestrian.
As methods of making a decision as to whether an object of collision is a pedestrian, there have been known techniques proposed in Japanese Patent Laid-Open Nos. HEI 11-028994 and HEI 11-310095. Japanese Patent Laid-Open No. HEI 11-028994 discloses the technique using a collision load (or deformation quantity), a duration thereof and a vehicle speed, while Japanese Patent Laid-Open No. HEI 11-310095 discloses the technique using a deformation quantity at a collision, its variation with time and a vehicle speed.
That is, these decision technique utilize the phenomenon in which, when a collision against a pedestrian occurs, a leg portion of the pedestrian is thrown up or dashed off after the collision. Concretely, a leg portion thereof departs from a bumper after the collision and, for this reason, the magnitude of a load or deformation quantity, to be detected by a sensor, attenuates after the collision against the vehicle. A decision on a pedestrian is made through the use of this phenomenon.
However, the pedestrian decision techniques disclosed in these documents encounter a problem in that the time for which a collision load or a deformation quantity exceeds a threshold (which will hereinafter be referred to as equally to a “collision detection duration”) varies diversely in accordance with a state of a leg portion of a pedestrian.
That is, in a case in which a vehicle speed is approximately 40 km/h, the time from which only one leg collides against a bumper until it is thrown up, or the time until both legs are thrown up by a bumper when both
Hattori Yoshiyuki
Takafuji Tetsuya
Denso Corporation
Jeanglaude Gertrude A.
Posz & Bethards, PLC
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