JP2014041053A - Vehicle side collision determining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle side collision determining device capable of shortening ignition time of an occupant protection unit and detecting side collision with high accuracy.SOLUTION: A vehicle side collision determining device 1 includes: first vibration detection means 30 which is built in a vehicle side door and detects high-frequency vibration in the acoustic band generated in a vehicle at the time of side collision; second vibration detection means 12 which detects low-frequency vibration in the vehicle width direction of a band lower than the acoustic band; and side collision determination means 13 which determines whether or not a side collision requiring starting an occupant protection unit has occurred on the basis of the detection results of the first vibration detection means and the second vibration detection means.

Description

  The present invention relates to a vehicle side collision determination device.

  Generally, an SRS (Supplemental Restraint System) airbag system is known as a system for protecting an occupant in the event of a vehicle collision. The SRS airbag system detects an occurrence of a vehicle collision based on acceleration data acquired from an acceleration sensor installed in each part of the vehicle and activates an occupant protection device such as an airbag.

  In order to detect a collision from the side of the vehicle, a plurality of side impact sensors (SIS) are provided on both sides of the vehicle, and the SRS unit (SRS airbag system is installed in the center of the vehicle). There is known a technique of determining whether or not a side collision has occurred by connecting to an ECU to be controlled and performing start-up control of an occupant protection device according to the side collision determination result (Cited document 1).

  In the side collision determination, generally, the main collision determination is performed based on the detection result of the SIS on the side where the collision has occurred, and the safing determination is performed based on the detection result of the acceleration sensor provided in the SRS-ECU. Further, the side airbag in the direction in which the side collision has occurred is activated based on the main determination and the safing determination.

JP-A-11-006840

When an acceleration sensor is used as the SIS, the ignition time of the occupant protection device is about 4 ms to 6 ms. However, in the case of a side collision, the collision approach to the occupant is remarkably intense, and there is a demand to activate the occupant protection device as soon as possible.
Further, when an acceleration sensor is used as the SIS, a low frequency band of 500 Hz or less is generated when hammering or the like, and there is a problem that a side collision may be erroneously detected.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a vehicle side collision determination device that can shorten the ignition time of the occupant protection device and can detect a side collision with high accuracy.

In order to achieve the above object, the present invention employs the following means.
A vehicle side collision determination device according to the first aspect of the present invention is disposed in a vehicle side door, and is disposed in the center of the vehicle, with first vibration detection means for detecting high frequency vibrations in an acoustic band generated in the vehicle at the time of a side collision. A second vibration detecting means for detecting low-frequency vibrations in a vehicle width direction in a band lower than the acoustic band, and based on detection results of the first vibration detecting means and the second vibration detecting means, And a side collision determination means for determining whether or not a side collision requiring activation has occurred.

  In the vehicle side collision determination device according to the second aspect of the present invention, in the vehicle side collision determination device according to the first aspect, the first vibration detection means detects a vibration in a frequency band of 5 kHz to 20 kHz as the high frequency vibration, The second vibration detecting means detects vibration in a frequency band of 0 Hz to 500 Hz as the low frequency vibration.

  The vehicle side collision determination apparatus according to the third aspect of the present invention is the vehicle side collision determination apparatus according to the first aspect or the second aspect, wherein the first calculation for calculating the envelope of the high frequency vibration detected by the first vibration detection means. A second computing means for calculating an integral value of low-frequency vibration detected by the second vibration detecting means, and a two-dimensional map having the envelope as a first axis and the integral value as a second axis, Map determination means for determining that a side collision that requires activation of the occupant protection device has occurred when the envelope and the integral value exceed a two-dimensional collision determination threshold value.

  A vehicle side collision determination apparatus according to a fourth aspect of the present invention is the vehicle side collision determination apparatus according to the first aspect or the second aspect, wherein the first calculation for calculating the envelope of the high frequency vibration detected by the first vibration detection means. Means, a second computing means for calculating an integral value of the low frequency vibration detected by the second vibration detecting means, and the occupant protection device is activated when the envelope and the envelope each exceed a predetermined threshold value. Threshold judging means for judging that the required side collision has occurred.

  A vehicle side collision determination device according to a fifth aspect of the present invention is the vehicle side collision determination device according to the third aspect or the fourth aspect, based on low frequency vibration in the vehicle width direction detected by the second vibration detection means. The occupant protection device needs to be activated based on the collision direction determination means for determining the direction of the side collision, the determination result of the map determination means or the threshold determination means, and the determination result of the collision direction determination means. Final determination means for determining whether or not a side collision has occurred.

  The vehicle side collision determination apparatus according to the sixth aspect of the present invention is the vehicle side collision determination apparatus according to the third aspect or the fourth aspect, wherein the side collision determination means is disposed in the center of the vehicle and occurs in the vehicle at the time of the collision. Third vibration detecting means for detecting high frequency vibrations in an acoustic band, safing determining means for determining side collision based on an envelope of high frequency vibrations detected by the third vibration detecting means, the map determining means or the threshold determining Final determination means for determining whether or not a side collision that requires activation of the occupant protection device has occurred based on the determination result of the means and the determination result of the safing determination means, To do.

According to the present invention, by using an acoustic sensor as the SIS, it is possible to shorten the ignition time of the occupant protection device.
Further, by using an acoustic sensor as the SIS, it is possible to provide a vehicle side collision determination device that reduces side collision erroneous detection and improves side collision determination accuracy.

It is a principal part block block diagram of the SRS airbag system and SRS unit 1 of 1st embodiment. It is a figure which shows the calculation process of the calculation process of a 1st calculating part, the two-dimensional map used for collision determination, and the safing determination part. It is a principal block block diagram of the SRS unit 2 of 2nd embodiment. It is a figure which shows the main part block block diagram of SRS unit 3 of 3rd embodiment, and the calculation process of a safing determination part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First embodiment]
FIG. 1A is a schematic configuration diagram of the SRS airbag system of the first embodiment.
The SRS airbag system of the first embodiment includes an SRS unit 1 (vehicle side collision determination device) installed at the center of the vehicle 100, and a side airbag 20 (occupant) installed on the sides of the driver seat and the passenger seat. Protective device) and a plurality of acoustic sensors 30 installed on the driver's seat door and the passenger's seat door, respectively.

  The SRS unit 1 includes an acoustic sensor 11 and an acceleration sensor 12. The SRS unit 1 determines whether or not a side collision has occurred in the vehicle 100 based on the output signal of the built-in acoustic sensor 11 and the output signal of the acoustic sensor 30 input from the outside (collision determination). It is ECU (Electronic Control Unit) which performs starting control of side airbag 20 according to a collision judgment result.

The side airbag 20 is an occupant protection device that is deployed in response to an ignition signal input from the SRS unit 1 and reduces injury caused by a side collision of the vehicle 100 that causes the occupant to collide sideways.
In addition to the side airbag 20, the vehicle 100 is also provided with other occupant protection devices such as a front airbag and a seat belt pretensioner, which are not shown in FIG.

The acoustic sensor 30 (first vibration detection means) is a vibration sensor built in a door installed on the left and right side surfaces of the vehicle 100 such as a driver's seat door or a passenger seat door. The acoustic sensor 30 detects high-frequency vibrations in the acoustic band that occur in the length direction (X-axis direction in the drawing) and the width direction (Y-axis direction in the drawing) of the vehicle 100. However, since the acoustic sensor 30 is built in the driver's seat door, the passenger's seat door, or the like, the acoustic sensor 30 detects high-frequency vibrations in the acoustic band mainly generated in the width direction of the vehicle 100 (Y-axis direction in the figure). And the detection result is output to the main collision determination part 13 as acoustic data Sa1 (t).
Specifically, the acoustic sensor 30 detects vibration (structural sound) in the frequency band 5 kHz to 20 kHz as high-frequency vibration in the acoustic band. The acoustic data Sa1 (t) obtained from the acoustic sensor 30 well captures the characteristic that the vehicle 100 is deformed (damaged) by a side collision.

FIG. 1B is a block diagram of the main part of the SRS unit 1.
The SRS unit 1 includes an acoustic sensor 11 (third vibration detection unit), an acceleration sensor 12 (second vibration detection unit), a main collision determination unit 13 (side collision determination unit), and a safing determination unit 14 (collision direction determination unit). And an AND section 15 (final determination means).

The acoustic sensor 11 is a vibration sensor like the acoustic sensor 30 and is mainly used for frontal collision determination. The acoustic sensor 11 is built in the SRS unit 1 and detects high-frequency vibrations in the acoustic band generated in the length direction (X-axis direction in the drawing) and the width direction (Y-axis direction in the drawing) of the vehicle 100, and the detection thereof. The result is output as acoustic data Sa2 (t) to the main collision determination unit for frontal collision determination (not shown).
Specifically, the acoustic sensor 11 detects vibration (structural sound) in the frequency band 5 kHz to 20 kHz as high-frequency vibration in the acoustic band. The acoustic data Sa2 (t) obtained from the acoustic sensor 11 well captures the characteristics that the vehicle 100 is deformed (damaged) by frontal collision (including offset collision) and side collision.

The acceleration sensor 12 is a vibration sensor built in the SRS unit 1, detects low-frequency vibration in a band lower than the acoustic band, which occurs in the width direction (Y-axis direction) of the vehicle 100, and uses the detection result as acceleration data Gy (T) is output to the main collision determination unit 13 and the safing determination unit 14.
Specifically, the acceleration sensor 12 detects vibration in the frequency band 0 Hz to 500 Hz as low frequency vibration in a band lower than the acoustic band. The acceleration data Gy (t) obtained from the acceleration sensor 12 well captures the deceleration in the Y-axis direction that occurs in the vehicle 100 due to a side collision.

As described above, the difference between the acoustic sensors 11 and 30 and the acceleration sensor 12 is that only the frequency band of the vibration to be detected is different, both of which belong to the vibration sensor. These acoustic sensors 11 and 30 and the acceleration sensor 12 constitute vibration detecting means in the present invention.
As shown in FIG. 1A, in the SRS unit 1, the acoustic sensor 11 and the acceleration sensor 12 may be provided separately, or the acoustic sensor 11 and the acceleration sensor 12 are built in one sensor cell. May be.

The main collision determination unit 13 needs to deploy (start up) the side airbag 20 based on the acoustic data Sa1 (t) input from the acoustic sensor 30 and the acceleration data Gy (t) input from the acceleration sensor 12. It is determined whether or not a collision has occurred.
A first calculation unit 13a (first calculation unit), a second calculation unit 13b (second calculation unit), and a map determination unit 13c (map determination unit) are provided.

FIG. 2A shows a calculation process of the first calculation unit.
The first calculation unit 13a performs a bandpass filtering process (frequency band 5 kHz to 20 kHz) on the acoustic data Sa1 (t) input from the acoustic sensor 30, calculates an absolute value of the processed data, and further calculates the absolute value of the absolute value. The envelope (envelope) is calculated.
Hereinafter, an absolute value envelope of the acoustic data Sa1 (t) is referred to as an acoustic envelope Se (t). The first calculation unit 13a outputs the acoustic envelope Se (t) calculated as described above to the map determination unit 13c.

The second calculation unit 13b calculates the velocity V (second calculation value) by performing linear integration (interval integration) on the acceleration data Gy (t) input from the acceleration sensor 12, and the calculation result is used as the map determination unit 13c. Output to.
As the second calculation value, instead of the speed V, the movement amount may be calculated by quadratic integration of the acceleration data Gy (t).

FIG. 2B is a diagram showing a two-dimensional map used for collision determination.
Based on the acoustic envelope Se (t) and the velocity V calculated by the first calculation unit 13a and the second calculation unit 13b, the map determination unit 13c has caused a side collision that requires the side airbag 20 to be deployed. It is determined whether or not.
Specifically, as shown in FIG. 2B, on the two-dimensional map with the acoustic envelope Se (t) as the vertical axis and the velocity V as the horizontal axis, the first calculation unit 13a and the second calculation unit 13b When the calculated acoustic envelope Se (t) and velocity V exceed a two-dimensionally set two-dimensional collision determination threshold TH, it is determined that a side collision that requires deployment of the side airbag 20 has occurred. The map determination result is output to the AND unit 15.

The method for setting the two-dimensional collision determination threshold TH on the two-dimensional map is as follows.
As already described, the acoustic data Sa1 (t) obtained from the acoustic sensor 30 tends to easily capture the characteristics of deformation (damage) of the vehicle body, and is effective in realizing quick and accurate side collision determination.

  On the two-dimensional map shown in FIG. 2 (b), the two-dimensional collision determination threshold TH (TH1) extending in the horizontal axis direction is a side collision (vehicle body deformation (damage)) that requires deployment of the side airbag 20. It is set to a value that can discriminate between a collision and a side collision that does not require deployment of the side airbag 20 (a gentle collision with slight deformation of the vehicle body).

Since the structural sound generated in the vehicle 100 increases as the speed V increases, if the two-dimensional collision determination threshold TH (TH1) extending in the horizontal axis direction is set to a constant value, the side airbag 20 is not normally deployed. There is a possibility of erroneous determination that a collision that requires deployment of the side airbag 20 has occurred despite the occurrence of a serious collision.
Therefore, in order to prevent such an erroneous determination, as shown in FIG. 2B, the two-dimensional collision determination threshold TH (TH1) extending in the horizontal axis direction is set so as to increase as the speed V increases. It is desirable.

On the other hand, the acoustic envelope Se (t) obtained from the acoustic sensor 30 contains a lot of local hitting sounds due to stepping stones and the like that are not accompanied by vehicle body deformation. For this reason, it is necessary to accurately discriminate between an impact sound due to a side collision that requires deployment of the side airbag 20 and a local impact sound that does not require deployment of the side airbag 20.
The acceleration data Gy (t) obtained from the acceleration sensor 12 can be used to discriminate between the impact sound due to the side collision and the local impact sound due to the flying stone. A large deceleration occurs when an impact sound is generated due to a side collision, but only a small deceleration occurs when a local impact sound such as a stepping stone is generated.

That is, on the two-dimensional map shown in FIG. 2B, the two-dimensional collision determination threshold TH (TH2) extending in the vertical axis direction is a side collision that requires deployment of the side airbag 20 (a severe collision with vehicle body deformation). ) And a side collision (local hit with a stepping stone or the like) that does not require the side airbag 20 to be deployed.
Even if the local impact sound due to stepping stones increases, there is no significant change in the deceleration caused by it, so the two-dimensional collision determination threshold TH (TH2) extending in the vertical axis direction is a constant value with respect to the acoustic envelope Se (t). Should be set.

The two-dimensional collision determination threshold TH is set on the two-dimensional map by the method as described above. Thereby, an airbag deployment region where the side airbag 20 is deployed and an airbag non-deployment region where the side airbag 20 is not deployed are formed on the two-dimensional map.
That is, the map determination unit 13c determines that the acoustic envelope Se (t) calculated by the first calculation unit 13a exceeds the two-dimensional collision determination threshold TH (TH1) and the speed calculated by the second calculation unit 13b. When V exceeds the two-dimensional collision determination threshold TH (TH2) (in other words, when the intersection of the acoustic envelope Se (t) and the velocity V is included in the airbag deployment region), the side airbag 20 It is determined that a side collision requiring deployment has occurred.

FIG. 2C shows a calculation process of the safing determination unit.
The safing determination unit 14 performs safing determination based on the acceleration data Gy (t) input from the acceleration sensor 12, and outputs the safety determination result to the AND unit 15.
Specifically, the safing determination unit 14 confirms the sign (positive / negative) of the acceleration data Gy (t) and compares the acceleration data Gy (t) with the safing determination threshold value, thereby expanding the right side airbag 20 of the vehicle 100. It is determined whether the side airbag 20 on the left side of the vehicle 100 is deployed.
That is, the safing determination unit 14 compares the positive component of the acceleration data Gy (t) with the safing determination threshold, and when the positive component is larger than the safing determination threshold, the side airbag 20 on the right side surface of the vehicle 100 is used. It is determined that a side collision that requires deployment (right side) has occurred. Then, a right side airbag safing permission signal is output.
On the other hand, the safing determination unit 14 compares the negative component of the acceleration data Gy (t) with the safing determination threshold, and when the negative component is smaller than the safing determination threshold, the side airbag 20 on the left side surface of the vehicle 100 is used. It is determined that a side collision that requires deployment (left side) has occurred. Then, a left side airbag safing permission signal is output.
Note that the safing determination threshold is set to a value (relatively low value) that is swung in a safe direction so that the side airbag 20 is reliably deployed when a certain degree of side collision (large deceleration) occurs. .

Returning to FIG. 1 (b), the AND unit 15 finally determines the side airbag 20 based on the collision determination result (map determination result) of the main collision determination unit 13 and the safing determination result of the safing determination unit 14. It is determined whether or not a side collision that needs to be unfolded has occurred, and the result of the collision determination is output.
Specifically, the AND unit 15 is finally used when both the main collision determination unit 13 and the safing determination unit 14 determine that a side collision requiring deployment of the side airbag 20 has occurred. It is determined that a side collision that requires activation of the side airbag 20 has occurred.

The SRS unit 1 configured in this manner has a side collision that requires the deployment of the side airbag 20 (a severe side collision with vehicle body deformation) and a side collision that does not require the deployment of the side airbag 20 (the vehicle body deformation is slight). Can be discriminated quickly and accurately.
By using the two-dimensional map shown in FIG. 2B for collision determination, a two-dimensional threshold can be set, and collision determination accuracy can be improved (occupant protection performance can be improved).
In addition, since the acoustic sensor 30 is used as the SIS, it can be performed more quickly than the conventional example using the acceleration sensor as the SIS. Therefore, it is possible to provide the SRS unit 1 having higher occupant protection performance than before.

[Second Embodiment]
In the description of the second embodiment, the description will be focused on differences from the first embodiment, and the same components as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

FIG. 3 is a principal block configuration diagram of the SRS unit 2 of the second embodiment.
The SRS unit 2 (vehicle side collision determination device) of the second embodiment includes a main collision determination unit 16 (side collision determination unit) that is different from the main collision determination unit 13 of the first embodiment.

  The main collision determination unit 16 performs side collision that requires deployment of the side airbag 20 based on the acoustic data Sa1 (t) input from the acoustic sensor 30 and the acceleration data Gy (t) input from the acceleration sensor 12. The first calculation unit 16a (first calculation unit), the second calculation unit 16b (second calculation unit), the first comparison unit 16c, the second comparison unit 16d, and the AND A portion 16e is provided. The first comparison unit 16c, the second comparison unit 16d, and the AND unit 16e constitute a threshold determination unit.

The first calculation unit 16a calculates the acoustic envelope Se (t) (first calculation value) from the acoustic data Sa1 (t) input from the acoustic sensor 30, and outputs the calculation result to the first comparison unit 16c.
The second calculation unit 16b calculates the velocity V (second calculation value) by linearly integrating the acceleration data Gy (t) input from the acceleration sensor 12, and outputs the calculation result to the second comparison unit 16d. .

The first comparison unit 16c determines whether or not the acoustic envelope Se (t) input from the first calculation unit 16a exceeds the first collision determination threshold value Sath, and outputs the comparison determination result to the AND unit 16e.
The second comparison unit 16d determines whether or not the speed V input from the second calculation unit 16b exceeds the second collision determination threshold value Vth, and outputs the comparison determination result to the AND unit 16e.
The AND unit 16e is determined by the first comparison unit 16c and the second comparison unit 16d that the acoustic envelope Se (t) exceeds the first collision determination threshold value Sath and the speed V exceeds the second collision determination threshold value Vth. If a side collision that requires deployment of the side airbag 20 has occurred, it is determined whether or not a side collision has occurred, and the collision determination result is output to the AND unit 15.

The first collision determination threshold value Sath includes a side collision that requires deployment of the side airbag 20 (a severe side collision with vehicle body deformation (damage)) and a side collision that does not require deployment of the side airbag 20 (the vehicle body deformation is slight). It is set to such a value that it can be discriminated from a gentle side impact.
The second collision determination threshold Vth discriminates between a side collision that requires deployment of the side airbag 20 (violent collision with deformation of the vehicle body) and a collision that does not require deployment of the side airbag 20 (local hit by a stepping stone or the like). It is set to a value that allows it.

Similarly to the SRS unit 1 of the first embodiment, the SRS unit 2 of the second embodiment configured as described above is a side collision that requires deployment of the side airbag 20 (a severe side collision with vehicle body deformation). Further, it is possible to quickly and accurately discriminate a side collision (a gentle side collision with a slight deformation of the vehicle body and a local hit by a stepping stone) that does not require the deployment of the side airbag 20.
Moreover, since the SRS unit 2 of the second embodiment also uses the acoustic sensor 30 as the SIS, it can be performed more quickly than in the past. Therefore, it is possible to provide the SRS unit 2 having high occupant protection performance.

[Third embodiment]
In the description of the third embodiment, the description will focus on differences from the first embodiment and the second embodiment, and the same components as those in the first embodiment and the second embodiment will be denoted by the same reference numerals. Description is omitted.

FIG. 4 is a block diagram showing a main part of the SRS unit 3 according to the third embodiment and a calculation process of the safing determination unit.
The SRS unit 3 (vehicle side collision determination device) of the third embodiment includes a safing determination unit 17 (safing determination unit) having a different configuration from the safing determination unit 14 of the first embodiment and the second embodiment. I have.

The safing determination unit 17 performs safing determination based on the acoustic data Sa2 (t) input from the acoustic sensor 11 built in the SRS unit 1, and outputs the safety determination result to the AND unit 15.
Specifically, the safing determination unit 17 calculates the vibration waveform energy E from the acoustic data Sa2 (t), and further compares the vibration waveform energy E with the safing determination threshold value to determine the left and right sides of the vehicle 100. It is determined whether or not the side airbag 20 is deployed.

  The energy change amount calculation unit 17a of the safing determination unit 17 performs absolute value calculation and interval integration. That is, the energy change amount calculation unit 17a calculates the absolute value | Sa2 (t) | of the input acoustic data Sa2 (t), and further integrates the absolute value | Sa2 (t) | E is calculated.

When the vibration waveform energy E is greater than the safing determination threshold Eth, the safing determination unit 17 determines that a side collision that requires deployment of the left and right side airbags 20 of the vehicle 100 has occurred. Then, a side airbag safing permission signal is output.
Note that the safing determination threshold Eth is set to a value (relatively low value) that is swung in a safe direction so that the side airbag 20 is reliably deployed if a certain degree of side collision (large deceleration) occurs. Yes.

The SRS unit 3 of the third embodiment configured as described above also has a side collision that requires deployment of the side airbag 20 (SRS unit 1 of the first embodiment and SRS unit 2 of the second embodiment). It is possible to quickly and accurately discriminate between a side collision with a vehicle body deformation) and a side collision that does not require the deployment of the side airbag 20 (a gentle side collision with a slight vehicle body deformation and a local blow by a flying stone).
Moreover, since the SRS unit 3 of the second embodiment uses the acoustic sensor 30 as the SIS, it can be performed more quickly than in the past. Therefore, the SRS unit 3 having high occupant protection performance can be provided.

  The present invention is not limited to the above-described embodiment, and can of course be changed without departing from the spirit of the present invention.

  The above embodiment exemplifies a case where vibration (structural sound) in the frequency band 5 kHz to 20 kHz is detected as the high frequency vibration in the acoustic band, and vibration in the frequency band 0 Hz to 500 Hz is detected as the low frequency vibration in the band lower than the acoustic band. However, the frequency band of the vibration to be detected is not limited to this. For example, what is necessary is just to set suitably according to the structure of the vehicle 100, and the passenger | crew protection performance requested | required. In other words, the frequency band of the high-frequency vibrations only needs to capture the characteristic (structural sound) that the vehicle 100 is deformed (damaged) by the side collision, and the frequency band of the low-frequency vibrations is the deceleration generated in the vehicle 100 by the side collision. If it is possible to capture.

  1, 2, 3 ... SRS unit (vehicle side collision determination device), 11 ... acoustic sensor (third vibration detection means), 12 ... acceleration sensor (second vibration detection means), 13 ... main collision determination section (side collision determination) Means), 13a... First computing section (first computing means), 13b... Second computing section (second computing means), 13c... Map determining section (map judging means), 14. Means), 15 ... AND part (final judging means), 16 ... main collision judging part (side collision judging means), 16a ... first computing part (first computing means), 16b ... second computing part (second computing means) ), 16c... First comparison section (threshold determination means), 16d... Second comparison section (threshold determination means), 16e... AND section (threshold determination means), 17. …sound Sensor (first vibration detection means), 100 ... vehicle

Claims (6)

First vibration detection means built in a vehicle side door for detecting high frequency vibrations in an acoustic band generated in the vehicle at the time of a side collision;
A second vibration detecting means disposed in the center of the vehicle for detecting low frequency vibrations in a vehicle width direction in a band lower than the acoustic band;
Side collision determination means for determining whether or not a side collision that requires activation of the occupant protection device has occurred based on the detection results of the first vibration detection means and the second vibration detection means;
A vehicle side collision determination device comprising: The first vibration detecting means detects a vibration in a frequency band of 5 kHz to 20 kHz as the high frequency vibration,
2. The vehicle side collision determination device according to claim 1, wherein the second vibration detection unit detects vibration in a frequency band of 0 Hz to 500 Hz as the low frequency vibration. The side collision determination means includes
First calculation means for calculating an envelope of high-frequency vibration detected by the first vibration detection means;
Second calculating means for calculating an integral value of the low frequency vibration detected by the second vibration detecting means;
On the two-dimensional map with the envelope as the first axis and the integral value as the second axis, the occupant protection device needs to be activated when the envelope and the integral value exceed the two-dimensional collision determination threshold. Map determination means for determining that a side collision has occurred;
The vehicle side collision determination device according to claim 1, further comprising: The side collision determination means includes
First calculation means for calculating an envelope of high-frequency vibration detected by the first vibration detection means;
Second calculating means for calculating an integral value of the low frequency vibration detected by the second vibration detecting means;
Threshold determination means for determining that a side collision that requires activation of the occupant protection device has occurred when the envelope and the envelope each exceed a predetermined threshold;
The vehicle side collision determination device according to claim 1, further comprising: The side collision determination means includes
A collision direction determination means for determining the direction of side collision based on the low frequency vibration in the vehicle width direction detected by the second vibration detection means;
Final determination means for determining whether or not a side collision that requires activation of the occupant protection device has occurred based on the determination result of the map determination means or the threshold determination means and the determination result of the collision direction determination means When,
The vehicle side collision determination device according to claim 3 or 4, further comprising: The side collision determination means includes
A third vibration detecting means disposed in the center of the vehicle for detecting high frequency vibrations in an acoustic band generated in the vehicle at the time of a collision;
Safing determining means for determining a side collision based on an envelope of high-frequency vibration detected by the third vibration detecting means;
Final determination means for determining whether or not a side collision requiring activation of the occupant protection device has occurred based on the determination result of the map determination means or the threshold determination means and the determination result of the safing determination means When,
The vehicle side collision determination device according to claim 3 or 4, further comprising:

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