They Invented What? (No. 159)

U.S. Pat. No. 6,784,792: Method and device for recognition of a collision with a pedestrian.

 

What is claimed is:

1. A method of detecting a pedestrian impact with a vehicle, the method comprising:

          providing at least one first sensor on a bumper and at least one second sensor in an area of a front edge of an engine hood;
         measuring one of a first pressure and a first deformation caused by the pedestrian impact;
         forming a first criterion for deciding whether the pedestrian impact has occurred by comparing at least one first sensor output signal with at least one first reference quantity and by comparing at least one second sensor output signal with at least one second reference quantity;
         determining at least one of a change in velocity of the vehicle and a change in acceleration of the vehicle caused by the pedestrian impact;
         forming a second criterion for deciding whether the pedestrian impact has occurred by at least one of comparing the change in velocity with a third reference quantity and comparing the change in acceleration with a fourth reference quantity; and
         determining that the pedestrian impact has occurred if both the first criterion and the second criterion are met.

2. The method according to claim 1, wherein the forming of the second criterion takes into account a braking that is initiated before the pedestrian impact.

3. The method according to claim 1, wherein the forming of the second criterion is based only on the change in acceleration if a braking is initiated before the pedestrian impact.

4. The method according to claim 1, wherein the forming of the first criterion includes:

         comparing an amplitude of the at least one first sensor output signal with a first reference amplitude typical of the pedestrian impact; and
         comparing an amplitude of the at least one second sensor output signal with a second reference amplitude typical of the pedestrian impact.

5. The method according to claim 1, further comprising:

         comparing a chronological sequence of the at least one first sensor output signal and the at least one second sensor output signal with a chronological signal typical of the pedestrian impact.

6. A device for detecting a pedestrian impact with a vehicle, comprising:

         at least one first sensor arranged on a bumper, the at least one first sensor measuring one of a first pressure and a first deformation caused by the pedestrian impact, the at least one first sensor producing a first sensor output signal;
         at least one second sensor arranged in an area of a front edge of an engine hood, the at least one second sensor measuring one of a second pressure and a second deformation caused by the pedestrian impact, the at least one second sensor producing a second sensor output signal;
         an arrangement for comparing the first sensor output signal with a first reference quantity and the one second sensor output signal with a second reference quantity in order to determine a first criterion for a decision as to whether the pedestrian impact has occurred;
         an arrangement for detecting at least one of a velocity change caused by the pedestrian impact and an acceleration change caused by the pedestrian impact;
         an arrangement for deriving a second criterion for the decision as to whether the pedestrian impact has occurred by comparing at least one of the velocity change to a third reference quantity and the acceleration change to a fourth reference quantity; and
         an arrangement for deciding that the pedestrian impact has occurred if both the first criterion and the second criterion are met.

7. The device according to claim 6, wherein the at least one first sensor includes a first wire strain gauge and the at least one second sensor includes a second wire strain gauge.

8. The device according to claim 6, wherein the at least one first sensor includes a first piezoelectric film and the at least one second sensor includes a second piezoelectric film.

9. The device according to claim 6, wherein the at least one first sensor and the at least one second sensor are based on an anisotropic magnetoresistive effect.

10. The device according to claim 6, wherein the at least one first sensor and the at least one second sensor are based on a Hall effect.

11. The device according to claim 6, wherein the at least one first sensor and the at least one second sensor include elements having pressure-dependent light-transmission characteristics.