Passive safety system and determination device

• US 20050161920A1
• Filed: 12/21/2004
• Published: 07/28/2005
• Est. Priority Date: 01/28/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Higuchi, Hiroshi, Ide, Seiya
• Granted Patent: US 7,406,376 B2
• Time in Patent Office: Days
• US Class Current: 280/735
• 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: B60R 21/01332 by frequency or waveform analysis
• CPC Class Codes: B60R 21/0136 responsive to actual contact with an obstacle , e.g. to vehicle deformation, bumper displacement or bumper velocity relative to the vehicle monitoring crash strength in combination with passenger seat detection B60R21/01558
• CPC Class Codes: B60R 21/0156 by deceleration

Abstract

A determination device includes a single acceleration sensor for measuring an acceleration of a vehicle and a determination circuit for determining severity of a collision in an accident. A plastic deformation pulse detection section and an elastic deformation pulse detection section of the determination circuit detect a plastic deformation pulse and an elastic deformation pulse, respectively, from a waveform of measured accelerations. A severity determination section of the detection circuit determines the severity of a collision based on a correlation between a vehicle speed and a plastic deformation pulse, and a correlation between the vehicle speed, the plastic deformation pulse, and an elastic deformation pulse.

Claims

1. A determination device for a passive safety device that operates according to severity of a collision in a vehicle accident comprising:

a single acceleration sensor that measures an acceleration of a vehicle; and

a determination circuit that includes a plastic deformation pulse detection section, an elastic deformation pulse detection section, and a severity determination section, wherein

the determination circuit is electrically connected with the acceleration sensor,

the plastic deformation pulse detection section detects a plastic deformation pulse by separating a plastic deformation pulse component from an acceleration waveform produced by the acceleration sensor,

the elastic deformation pulse detection section detects an elastic deformation pulse by separating an elastic deformation pulse component from the acceleration waveform, and

the severity determination section determines the severity of a collision based on a correlation between a vehicle speed and the plastic deformation pulse, and correlations between the vehicle speed, the plastic deformation pulse, and the elastic deformation pulse.

2. The determination device according to claim 1, wherein the severity determination section determines the severity of a collision based on a first peak that appears in the plastic deformation pulse immediately after a first impact on the vehicle in the collision.

3. The determination device according to claim 1, wherein:

the plastic deformation pulse detection section calculates a first average acceleration of the plastic deformation pulse in a predetermined time interval;

the elastic deformation pulse detection section calculates a second average acceleration of the elastic deformation pulse in a predetermined time interval; and

the severity determination section calculates a weighting factor by dividing the first average acceleration by the second average acceleration; and

the severity determination section determines the severity of a collision using the weighting factor.

4. The determination device according to claim 3, wherein:

the severity determination section calculates a severity operator by multiplying the weighting factor by any one of an unprocessed acceleration data outputted from the acceleration sensor, the first average acceleration, and the second average acceleration; and

the severity determination section determines the severity based on the severity operator.

5. The determination device according to claim 4, wherein the severity determination section calculates the severity operator by multiplying the weighting factor by the first average acceleration.

6. The determination device according to claim 1, wherein:

the plastic deformation pulse detection section calculates a first average acceleration of the plastic deformation pulse in a predetermined time interval;

the elastic deformation pulse detection section calculates a second average acceleration of the elastic deformation pulse in a predetermined time interval;

the severity determination section calculates a weighting factor by dividing an absolute value of the first average acceleration minus the second average acceleration by he second average acceleration; and

the severity determination section determines the severity of a collision using the weighting factor.

7. The determination device according to claim 6, wherein:

the severity determination section calculates a severity operator by multiplying the weighting factor by the absolute value when the second average acceleration is higher than a predetermined threshold; and

the severity determination section determines the severity of a collision using the severity operator.

8. The determination device according to claim 1, wherein:

the plastic deformation pulse detection section calculates a first average acceleration of the plastic deformation pulse in a predetermined time interval;

the elastic deformation pulse detection section calculates a second average acceleration of the elastic deformation pulse in a predetermined time interval;

the severity determination section calculates a severity operator by taking an absolute value of the first average acceleration and the second average acceleration when the second average acceleration is lower than a predetermined threshold; and

the severity determination section determines the severity of a collision using the severity operator.

9. The determination device according to claim 1, wherein:

the plastic deformation pulse detection section further includes a high pass filter; and

the plastic deformation pulse detection section detects the plastic deformation pulse by separating the plastic deformation pulse component with the high pass filter.

10. The determination device according to claim 1, wherein the plastic deformation pulse detection section detects the plastic deformation pulse by removing the elastic deformation pulse component from the acceleration waveform.

11. The determination device according to claim 1, wherein:

the elastic deformation pulse detection section further includes a low pass filter; and

the elastic deformation pulse detection section detects the elastic deformation pulse by separating the elastic deformation pulse component with the low pass filter.

12. The determination device according to claim 1, wherein the elastic deformation pulse detection section detects the elastic deformation pulse by removing the plastic deformation pulse form the acceleration waveform.

13. The determination device according to claim 1, wherein the acceleration sensor and the determination circuit are arranged in a module.

14. The determination device according to claim 13, wherein the module is arranged in about a middle of a side-to-side line of the vehicle.

15. The determination device according to claim 1, wherein:

the vehicle speed and the plastic deformation pulse have a relationship in which an amplitude of the plastic deformation pulse varies in proportion to the vehicle speed; and

the vehicle speed, the plastic deformation pulse, and the elastic deformation pulse have a relationship in which appearance of the first peak in the plastic deformation pulse with respect to the elastic deformation pulse varies in proportion to the vehicle speed.

16. A passive safety system comprising:

a determination device that includes a single acceleration sensor and a determination circuit; and

a passive safety device, wherein

the acceleration sensor measures an acceleration of the vehicle,

the determination circuit is connected with the acceleration sensor,

the determination circuit includes a plastic deformation pulse detection section, an elastic deformation pulse detection section, and a severity determination section,

the plastic deformation pulse detection section detects a plastic deformation pulse by separating a plastic deformation pulse component from a waveform of measured accelerations,

the elastic deformation pulse detection section detects an elastic deformation pulse by separating an elastic deformation pulse component from the acceleration waveform,

the severity determination section determines a severity of a collision based on a correlation between a vehicle speed and the plastic deformation pulse, and correlations between the vehicle speed, the plastic deformation pulse, and the elastic deformation pulse,

the passive safety device is electrically connected with the determination device, and

the passive safety device is operated according to the severity.

17. The passive safety system according to claim 16, wherein:

the passive safety device is an airbag system having multiple inflators and an airbag that is inflated by at least one of the inflators; and

the determination device determines actuation of each inflator based on the severity.

18. The passive safety system according to claim 17, wherein the airbag is inflated to different levels of pressures in multiple steps.

19. The passive safety system according to claim 16, further includes an electronic control unit for controlling operation of the passive safety device, wherein the acceleration sensor and the determination circuit are modularized and arranged in the electronic control unit.

20. The passive safety system according to claim 19, wherein the electronic control unit is arranged in about a middle of a side-to-side line of the vehicle.