JP2013124020A - Vehicle collision determination apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle collision determination apparatus that accurately performs collision determination even when local hitting, which does not require starting of an occupant protection apparatus under normal circumstances, occurs.SOLUTION: The vehicle collision determination apparatus includes: a vibration detecting means (an acoustic sensor 11 and an acceleration sensor 12) that detects high-frequency vibration in the acoustic band generated in a vehicle 100 in collision and low-frequency vibration in a band lower than the acoustic band; and a collision determination means that determines whether or not a collision requiring starting of an occupant protection apparatus occurs on the basis of the detection results of the high-frequency vibration and the low-frequency vibration. The collision determination means calculates a first calculation value based on the detection result of the high-frequency vibration and calculates a second calculation value based on the detection result of the low-frequency vibration, and determines that a collision does not occur yet regardless of the magnitude of the first calculation value when the second calculation value is below a predetermined threshold.

Description

 The present invention relates to a vehicle collision determination device.

  Generally, an SRS (Supplemental Restraint System) airbag system is known as a system for protecting an occupant during 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 Patent Document 1 below, in addition to a unit sensor installed in an SRS unit (ECU for overall control of the SRS airbag system) installed in the center of the vehicle, a plurality of front crashes installed in the front of the vehicle An SRS airbag system comprising a sensor is disclosed. In this system, based on the acceleration data obtained from the unit sensor and the front crash sensor, it is determined whether or not a frontal collision (including frontal collision, offset collision, and oblique collision) has occurred, and depending on the determination result To control the activation of the occupant protection device.

  In recent years, the development of CISS (Crash Impact Sound Sensing) technology has been progressing in which an impact sound generated due to vehicle body deformation at the time of a collision is detected using an acoustic sensor and a collision is determined based on the detection result. Yes. Patent Document 2 below discloses a technique for detecting a shake of a bulk acoustic wave in a transversal direction generated in a vehicle body element (side member) at the time of a vehicle collision using a bulk acoustic wave sensor, and performing a collision determination based on the detection result. It is disclosed.

  The acceleration sensor and the acoustic sensor described above belong to the vibration sensor that detects vibration, but the frequency bands of the vibrations to be detected are different. In general, an acceleration sensor detects low frequency vibrations in a frequency band of 0 Hz to 400 Hz and outputs them as acceleration data, and an acoustic sensor detects high frequency vibrations in a frequency band of 5 kHz to 20 kHz (acoustic band) as acoustic data. Output.

Japanese Patent Laid-Open No. 10-287203 Special table 2001-519268 gazette

  By the way, in Patent Document 1 described above, the front crash sensor is used in addition to the unit sensor because the vehicle collision mode is a mode that requires the activation of the occupant protection device or the activation of the occupant protection device is not required. This is to quickly and accurately determine whether the mode is correct. The collision mode that requires activation of the passenger protection device is, for example, a high-speed offset collision, and the collision mode that does not require activation of the passenger protection device is, for example, a low-speed offset collision.

  Specifically, since the unit sensor is installed in the center of the vehicle where the deformation of the vehicle body at the time of a frontal collision is small, it takes a long time (about approx. 40 ms or more). Here, from the viewpoint of occupant protection, since it is ideal that the activation of the occupant protection device is between 20 and 30 ms from the time of occurrence of the collision, the occupant protection performance required by the unit sensor alone cannot be satisfied. Therefore, conventionally, a front crash sensor is provided in the front part of the vehicle that greatly deforms the vehicle body at the time of a frontal collision, thereby realizing a quick and accurate collision determination.

  Since the front crash sensor causes an increase in system cost, it is ideal to make a collision determination using only the unit sensor built in the SRS unit. The protection performance cannot be satisfied. Therefore, an attempt has been made to construct a system that does not require a front crash sensor by using an acoustic sensor instead of an acceleration sensor as a unit sensor. The acoustic data obtained from the acoustic sensor has a tendency to easily capture the characteristics of deformation (damage) of the vehicle body, and the collision mode can be easily determined, which is considered to be effective for realizing quick and accurate collision determination.

  However, as a result of the collision test by the present applicant, it has been confirmed that a large structural sound is generated by local hitting such as stepping stones and hammering on the vehicle body, and when performing a collision determination only with acoustic data obtained from an acoustic sensor, There is a possibility that a structural sound generated by local hitting that does not need to activate the occupant protection device is captured and erroneously determined that a collision has occurred (that is, the occupant protection device may malfunction).

 The present invention has been made in view of the above-described circumstances, and it is possible to accurately perform a collision determination even when a local hit such as a stepping stone or hammering that originally does not need to start an occupant protection device occurs. An object of the present invention is to provide a vehicle collision determination device.

In order to solve the above-described problem, a vehicle collision determination device according to the present invention includes a vibration detection unit that detects high-frequency vibration in an acoustic band generated in a vehicle at the time of a collision and low-frequency vibration in a band lower than the acoustic band, and the high-frequency Collision determination means for determining whether or not a collision that requires activation of an occupant protection device has occurred based on detection results of vibration and low-frequency vibration, wherein the collision determination means detects the high-frequency vibration A first calculated value is calculated based on the result, and a second calculated value is calculated based on the detection result of the low frequency vibration. When the second calculated value is equal to or less than a predetermined threshold, the first calculated value is large. Regardless of this, it is characterized in that it is determined that no collision has occurred.
Here, in the vehicle collision determination device according to the present invention, the vibration detection unit detects a vibration of a frequency band of 5 kHz to 20 kHz as the high frequency vibration, and a vibration of a frequency band of 0 Hz to 400 Hz as the low frequency vibration. And a second vibration sensor for detecting the vibration.
Alternatively, in the vehicle collision determination device according to the present invention, the vibration detection unit detects broadband vibration including the high frequency vibration and low frequency vibration, and the high frequency vibration is detected from the broadband vibration detected by the vibration detection unit. It is characterized by comprising first extracting means for extracting, and second extracting means for extracting the low frequency vibration from the broadband vibration detected by the vibration detecting means.
Here, in the vehicle collision determination device according to the present invention, the first extraction unit extracts a vibration of a frequency band of 5 kHz to 20 kHz as the high frequency vibration from the broadband vibration, and the second extraction unit extracts the vibration from the broadband vibration. It is characterized by extracting vibrations in the frequency band 0 Hz to 400 Hz as low frequency vibrations.
In the vehicle collision determination device according to the present invention, the collision determination means includes first calculation means for calculating an envelope of the high frequency vibration as the first calculation value, and an integrated value of the low frequency vibration as the second calculation value. On a two-dimensional map with the envelope as the first axis and the integral value as the second axis, the envelope calculated by the first calculation means and the second calculation means, and the envelope When the integral value exceeds the two-dimensional collision determination threshold value, it is determined that a collision that requires activation of the occupant protection device has occurred, and when the integral value is equal to or less than the two-dimensional collision determination threshold value, Map determining means for determining that no collision has occurred regardless of the size of the envelope is provided.
Alternatively, in the vehicle collision determination device according to the present invention, the collision determination means includes first calculation means for calculating an envelope of the high-frequency vibration as the first calculation value, and an integrated value of the low-frequency vibration as the second calculation value. A collision that requires the occupant protection device to be activated when the envelope exceeds a first collision determination threshold value and the integral value exceeds a second collision determination threshold value. On the other hand, when the integrated value is less than or equal to the second collision determination threshold value, threshold value determination means for determining that no collision has occurred regardless of the size of the envelope is provided.
Here, the vehicle collision determination device of the present invention is characterized in that the first calculation means calculates an absolute value envelope of the high-frequency vibration.
The vehicle collision determination device according to the present invention includes a safing determination unit that performs safing determination based on the detection result of the low-frequency vibration, a collision determination result of the collision determination unit, and a safing determination of the safing determination unit. And a final determination means for determining whether or not a collision that finally requires the activation of the occupant protection device has occurred based on the result.

The high-frequency vibrations in the acoustic band generated in the vehicle include structural sounds generated when the vehicle body is deformed (damaged) in the event of a collision, as well as structural sounds caused by local impacts such as stepping stones and hammering that do not cause vehicle body deformation. Therefore, it is necessary to accurately discriminate between a structural sound caused by a collision that requires activation of the occupant protection device and a structural sound caused by local hitting that does not require activation of the occupant protection device.
For this determination, low-frequency vibrations in a band lower than the acoustic band generated in the vehicle can be used. Low-frequency vibration in a band lower than the acoustic band has a feature that it is easy to capture the deceleration generated in the vehicle due to a collision. When a collision occurs, a large deceleration occurs in the vehicle, but when a local hit occurs, only a small deceleration occurs.
That is, in the present invention, the first calculation value is calculated based on the detection result of the high frequency vibration in the acoustic band generated in the vehicle, and the second calculation value is calculated based on the detection result of the low frequency vibration in the band lower than the acoustic band. When the second calculated value is less than or equal to a predetermined threshold value, it is determined that no collision has occurred regardless of the magnitude of the first calculated value, thereby causing a collision (deformation of the vehicle body) that requires activation of the occupant protection device. ) And a local impact that does not require activation of the occupant protection device can be accurately discriminated to prevent erroneous determination due to the local impact.
Therefore, according to the present invention, it is possible to accurately perform a collision determination even when a local hit such as a stepping stone or hammering that does not normally need to start the occupant protection device occurs.

The top view (a) which shows schematic structure of the vehicle provided with the SRS airbag system in 1st Embodiment of this invention, and the block diagram (b) which shows the principal part structure of the SRS unit 1 in 1st Embodiment of this invention. is there. It is a figure which shows the time change of the acoustic envelope Se (t) obtained at the time of the two-dimensional map used for a collision determination, and a high-speed offset collision and a low-speed offset collision, respectively. It is a block diagram which shows the principal part structure of SRS unit 1A, 1B in 2nd, 3rd embodiment of this invention.

 Hereinafter, a vehicle collision determination device according to an embodiment of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
Fig.1 (a) is a top view which shows schematic structure of a vehicle provided with the SRS airbag system in 1st Embodiment of this invention. As shown in FIG. 1A, the SRS airbag system provided in the vehicle 100 includes an SRS unit 1 (vehicle collision determination device) installed in the center of the vehicle 100, and a driver seat and a passenger seat of the vehicle 100, respectively. It is comprised from the installed airbag 2 (occupant protection apparatus).

  The SRS unit 1 determines whether or not a frontal collision has occurred in the vehicle 100 based on the output signals of the built-in acoustic sensor 11 and acceleration sensor 12 (collision determination), and an airbag according to the collision determination result. 2 is an ECU (Electronic Control Unit) that performs start-up control. The airbag 2 is an occupant protection device that is deployed in response to an ignition signal from the SRS unit 1 and reduces injury caused by a occupant secondary collision forward due to a frontal collision of the vehicle 100. In general, the vehicle 100 is provided with other occupant protection devices such as a seat belt pretensioner in addition to the airbag 2, but the illustration is omitted in FIG.

  FIG.1 (b) is a block diagram which shows the principal part structure of the SRS unit 1 in 1st Embodiment of this invention. As shown in FIG. 1B, the SRS unit 1 includes an acoustic sensor 11 (first vibration sensor), an acceleration sensor 12 (second vibration sensor), a main collision determination unit 13 (collision determination unit), and a safing determination unit 14. (Safety determining means) and an AND section 15 (final determining means).

  The acoustic sensor 11 is a vibration sensor built in the SRS unit 1, detects high-frequency vibrations in the acoustic band that occurs in the front-rear direction of the vehicle 100 (the X direction in FIG. 1A), and the detection result is used as acoustic data. It outputs to the main collision determination part 13 as Sa (t). Specifically, the acoustic sensor 11 detects vibration (structural sound) in the frequency band 5 kHz to 20 kHz. The acoustic data Sa (t) obtained from the acoustic sensor 11 well captures the characteristic that the vehicle 100 is deformed (damaged) by a frontal collision.

  The acceleration sensor 12 is a vibration sensor built in the SRS unit 1, detects low-frequency vibrations in a band lower than the acoustic band generated in the front-rear direction of the vehicle 100, and uses the detection result as acceleration data G (t). It outputs to the collision determination part 13 and the safing determination part 14. Specifically, the acceleration sensor 12 detects vibrations in the frequency band 0 Hz to 400 Hz. The acceleration data G (t) obtained from the acceleration sensor 12 captures well the deceleration generated in the vehicle 100 due to the frontal collision.

  As described above, both the acoustic sensor 11 and the acceleration sensor 12 belong to a vibration sensor that detects vibration, but have different frequency bands of vibrations to be detected. The acoustic sensor 11 and the acceleration sensor 12 constitute vibration detecting means in the present invention. The acoustic sensor 11 and the acceleration sensor 12 may be separately provided in the SRS unit 1 as shown in FIG. 1A, or may be incorporated in one sensor cell.

 The main collision determination unit 13 includes 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). The main collision determination unit 13 having such a configuration is a collision that requires deployment (activation) of the airbag 2 based on the acoustic data Sa (t) from the acoustic sensor 11 and the acceleration data G (t) from the acceleration sensor 12. Whether or not has occurred is determined.

  The first calculation unit 13a calculates the absolute value of the acoustic data Sa (t) from the acoustic sensor 11, and calculates an envelope (envelope) of the calculated absolute value. Hereinafter, the envelope of the absolute value of the acoustic data Sa (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 movement amount ΔS (integration value) by secondarily integrating the acceleration data G (t) from the acceleration sensor 12 within a certain time interval, and the calculation result is used as a map determination unit. To 13c. The acceleration data G (t) may be linearly integrated to calculate the speed change amount ΔV, and the speed change amount ΔV may be output to the map determination unit 13c instead of the movement amount ΔS. The movement amount ΔS is more stable than the speed change amount ΔV.

  Whether the map determination unit 13c has encountered a collision that requires the airbag 2 to be deployed based on the acoustic envelope Se (t) and the movement amount ΔS calculated by the first calculation unit 13a and the second calculation unit 13b, respectively. Determine whether or not. Specifically, as shown in FIG. 2A, the acoustic envelope Se (t) and the movement amount ΔS are 2 on the two-dimensional map having the acoustic envelope Se (t) as the vertical axis and the movement amount ΔS as the horizontal axis. When the two-dimensional collision determination threshold TH set in dimension is exceeded, it is determined that a collision that requires deployment of the airbag 2 has occurred, and the map determination result is output to the AND unit 15.

  A method for setting the two-dimensional collision determination threshold TH on the two-dimensional map is as follows. As described above, the acoustic data Sa (t) obtained from the acoustic sensor 11 tends to capture the characteristics of deformation (damage) of the vehicle body, and it is easy to discriminate between a high-speed offset collision and a low-speed offset collision. This is effective for realizing a collision detection. FIG. 2B is a diagram illustrating temporal changes in the acoustic envelope Se (t) obtained at the time of the high-speed offset collision and the low-speed offset collision.

  As shown in FIG. 2B, in the acoustic envelope Se (t) obtained at the time of the high-speed offset collision, the first large peak P1 appears between about 10 to 15 ms from the collision occurrence time (time 0). To about 15-20 ms, the next large peak P2 appears. On the other hand, the first large peak P3 appears in the acoustic envelope Se (t) obtained at the time of the low-speed offset collision when about 18 ms elapses from the collision occurrence time.

  Referring to FIG. 2 (b), the peak P1 of the acoustic envelope Se (t) obtained at the time of the high speed offset collision is almost the same size as the peak P3 of the acoustic envelope Se (t) obtained at the time of the low speed offset collision. It can be seen that the peak P2 of the acoustic envelope Se (t) obtained at the time of the high-speed offset collision is sufficiently larger than the peak P3. Here, since the size of the peak P1 changes depending on the structure and material of the collision partner, the high-speed offset collision and the low-speed offset collision can be performed by performing the collision determination using the peak P2 without the peak P1. Can be accurately determined.

  Accordingly, on the two-dimensional map shown in FIG. 2A, the two-dimensional collision determination threshold TH (TH1) extending in the horizontal axis direction uses the peak P2 while excluding the peak P1 shown in FIG. 2B. It is set to a value that allows collision detection. That is, the two-dimensional collision determination threshold TH (TH1) is set to a value that is larger than the maximum value of the peak P3 considering the structure and material of the collision partner and is equal to or less than the maximum value of the peak P2.

  Since the structural sound generated in the vehicle 100 increases as the movement amount ΔS increases, if the two-dimensional collision determination threshold TH (TH1) extending in the horizontal axis direction is set to a constant value, the airbag 2 is originally deployed. Although there is an unnecessary collision, there is a possibility that it is erroneously determined that a collision that requires deployment of the airbag 2 has occurred. Therefore, in order to prevent such erroneous determination, as shown in FIG. 2A, the two-dimensional collision determination threshold TH (TH1) extending in the horizontal axis direction is set so as to increase as the movement amount ΔS increases. It is desirable.

  On the other hand, since the acoustic data Sa (t) obtained from the acoustic sensor 11 contains a lot of structural sounds due to local hits such as stepping stones and hammering without deformation of the vehicle body, a structure due to a collision that requires the airbag 2 to be deployed. It is necessary to accurately discriminate between a sound and a structural sound caused by local hitting that does not require the airbag 2 to be deployed. The acceleration data G (t) obtained from the acceleration sensor 12 can be used to discriminate between the structural sound caused by the collision and the structural sound caused by the local impact sound. A large deceleration occurs when a structural sound is generated by a collision, but only a small deceleration occurs when a structural sound is generated by a local impact.

  That is, on the two-dimensional map shown in FIG. 2A, the two-dimensional collision determination threshold TH (TH2) extending in the vertical axis direction is a collision that requires the airbag 2 to be deployed (a severe collision accompanied by vehicle body deformation). The value is set such that a collision that does not require the airbag 2 to be deployed (local impact such as stepping stones) can be determined. Note that even if the structural sound due to local hitting such as stepping stones increases, there is no significant change in the deceleration due to this, so the two-dimensional collision determination threshold TH (TH2) extending in the vertical axis direction is set in the acoustic envelope Se (t). On the other hand, it may be set to a substantially constant value.

  By setting the two-dimensional collision determination threshold value TH on the two-dimensional map by the method as described above, the airbag deployment region where the airbag 2 is deployed and the airbag 2 are deployed on the two-dimensional map. No airbag undeployed region is formed. That is, in the map determination unit 13c shown in FIG. 1B, the acoustic envelope Se (t) calculated by the first calculation unit 13a exceeds the two-dimensional collision determination threshold TH (TH1), and the second calculation unit 13b. Is greater than the two-dimensional collision determination threshold TH (TH2) (in other words, the intersection between the acoustic envelope Se (t) and the movement amount ΔS is included in the airbag deployment region). It is determined that a collision requiring deployment of the airbag 2 has occurred.

  Further, the map determination unit 13c, when the movement amount ΔS calculated by the second calculation unit 13b is equal to or less than the two-dimensional collision determination threshold TH (TH2), the acoustic envelope Se calculated by the first calculation unit 13a. Regardless of the size of (t), it is determined that no collision has occurred. Thereby, it is possible to accurately discriminate between a collision that requires deployment of the airbag 2 (collision involving deformation of the vehicle body) and a local blow that does not require deployment of the airbag 2, thereby preventing erroneous determination due to the local blow. it can.

  Returning to FIG. 1B, the safing determination unit 14 performs safing determination based on the acceleration data G (t) input from the acceleration sensor 12, and outputs the safing determination result to the AND unit 15. Specifically, the safing determination unit 14 compares a primary integration value (or a secondary integration value) of the acceleration data G (t) with a safing determination threshold, and the primary integration value is greater than the safing determination threshold. In this case, it is determined that a collision that requires the airbag 2 to be deployed has occurred. Note that the safing determination threshold is set to a value (relatively low value) swung in the safe direction so that the airbag 2 is reliably deployed when a certain degree of collision (large deceleration) occurs.

  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, the AND unit 15 finally generates a collision that requires the airbag 2 to be deployed. It is determined whether or not the collision has occurred, and the collision determination result is output. Specifically, when the AND unit 15 determines that a collision requiring deployment of the airbag 2 has occurred in both the main collision determination unit 13 and the safing determination unit 14, the AND unit 15 finally It is determined that a collision requiring activation has occurred.

  The SRS unit 1 configured as described above has a collision that requires deployment of the airbag 2 (including a high-speed offset collision and a severe collision accompanied by vehicle body deformation) and a collision that does not require deployment of the airbag 2 (low-speed offset collision). Can be discriminated quickly and accurately regardless of the structure or material of the collision partner. In addition, by using the two-dimensional map shown in FIG. 2A for collision determination, a two-dimensional threshold can be set, and collision determination accuracy can be improved (occupant protection performance can be improved).

[Second Embodiment]
FIG. 3A is a block diagram showing a main configuration of the SRS unit 1A in the second embodiment of the present invention. In the following, 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 description thereof will be omitted. As shown in FIG. 3A, the SRS unit 1A in the present embodiment has a configuration in which the main collision determination unit 13 of the SRS unit 1 in the first embodiment is replaced with a main collision determination unit 16.

 The main collision determination unit 16 includes a first calculation unit 16a (first calculation unit), a second calculation unit 16b (second calculation unit), a first comparison unit 16c, a second comparison unit 16d, and an AND unit 16e. Therefore, based on the acoustic data Sa (t) from the acoustic sensor 11 and the acceleration data G (t) from the acceleration sensor 12, it is determined whether or not a collision requiring deployment of the airbag 2 has occurred. Of the above-described components, the first comparison unit 16c, the second comparison unit 16d, and the AND unit 16e constitute threshold determination means in the present invention.

  The first calculation unit 16a calculates an absolute value envelope (acoustic envelope Se (t)) of the acoustic data Sa (t) from the acoustic sensor 11, and outputs the calculation result to the first comparison unit 16c. The second calculation unit 16b calculates the movement amount ΔS (second calculation value) by quadratic integration of the acceleration data G (t) from the acceleration sensor 12, and outputs the calculation result to the second comparison unit 16d. . The acceleration data G (t) may be linearly integrated to calculate the speed change amount ΔV, and the calculation result may be output to the second comparison unit 16d.

  The first comparison unit 16c determines whether or not the acoustic envelope Se (t) from the first calculation unit 16a exceeds the first collision determination threshold value Seth, and outputs the comparison determination result to the AND unit 16e. The second comparison unit 16d determines whether or not the movement amount ΔS from the second calculation unit 16b exceeds the second collision determination threshold value ΔSth, 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 Seth and the movement amount ΔS exceeds the second collision determination threshold value ΔSth. If a collision that requires deployment of the airbag 2 occurs, the collision determination result is output to the AND unit 15.

  Here, the first collision determination threshold value Seth is set to a value that allows the collision determination using the peak P2 while excluding the peak P1 shown in FIG. That is, the first collision determination threshold value Seth is set to a value that is larger than the maximum value of the peak P3 taking into account the structure and material of the collision partner and is equal to or less than the maximum value of the peak P2. Further, the second collision determination threshold value ΔSth can discriminate between a collision that requires the airbag 2 to be deployed (a severe collision with deformation of the vehicle body) and a collision that does not require the airbag 2 to be deployed (local hit with a stepping stone or the like). It is set to such a value.

  Similarly to the SRS unit 1 of the first embodiment, the SRS unit 1A configured as described above has a collision that requires the airbag 2 to be deployed (a severe collision involving a vehicle body deformation including a high-speed offset collision), an air Collisions that do not require deployment of the bag 2 (including low-speed offset collisions, gentle collisions with slight deformation of the vehicle body, and local hits by stepping stones, etc.) quickly and accurately regardless of the structure and material of the collision partner Can be determined.

[Third Embodiment]
FIG.3 (b) is a block diagram which shows the principal part structure of the SRS unit 1B in 3rd Embodiment of this invention. In the following, description will be made focusing on differences from the first and second embodiments, and the same components as those in the first and second embodiments will be denoted by the same reference numerals and description thereof will be omitted. As shown in FIG. 3B, the SRS unit 1B in the present embodiment includes a vibration sensor 20 (vibration detection means), a BPF (bandpass filter) 21 (first extraction means), and an LPF (low-pass filter) 22 (second filter). Extraction means), a main collision determination unit 13 similar to the first embodiment (may be a main collision determination unit 16 similar to the second embodiment), a safing determination unit 14 similar to the first and second embodiments, and An AND unit 15 is provided.

  The vibration sensor 20 detects wideband vibration (for example, vibration with a frequency band of 0 Hz to 30 kHz) generated in the front-rear direction of the vehicle 100 and outputs the detection result to the BPF 21 and the LPF 22 as vibration data Vb (t). The BPF 21 extracts high-frequency vibration in the acoustic band from the vibration data Vb (t) from the vibration sensor 20, and outputs the extraction result (detection result of high-frequency vibration) to the main collision determination unit 13 as acoustic data Sa (t). . Specifically, the BPF 21 extracts vibrations (structural sounds) in the frequency band 5 kHz to 20 kHz from the vibration data Vb (t). The LPF 22 extracts low-frequency vibrations in a band lower than the acoustic band from the vibration data Vb (t) from the vibration sensor 20, and determines the main collision using the extraction result (low-frequency vibration detection result) as acceleration data G (t). Output to the unit 13 and the safing determination unit 14. Specifically, the LPF 22 extracts vibrations in the frequency band 0 Hz to 400 Hz from the vibration data Vb (t).

  As described above, in this embodiment, instead of the two vibration sensors (acoustic sensor 11 and acceleration sensor 12) used in the first and second embodiments, wideband vibration in the frequency band 0 Hz to 30 kHz is detected. Only one vibration sensor 20 capable of the above is used. The vibration component of the frequency band 0 Hz to 400 Hz extracted by the LPF 22 from the detection result of the vibration sensor 20 is used as the acceleration data G (t), and the frequency band of 5 kHz to 20 kHz extracted by the BPF 21 from the detection result of the vibration sensor 20. The vibration component is used as acoustic data Sa (t). In the SRS unit 1B having such a configuration, the same effects as those of the first and second embodiments can be obtained.

[Modification]
The present invention is not limited to the above embodiment, and can be freely changed within the scope of the present invention. For example, in the above-described embodiment, when vibration (structural sound) in the frequency band 5 kHz to 20 kHz is detected as high frequency vibration in the acoustic band, and vibration in the frequency band 0 Hz to 400 Hz is detected as low frequency vibration in a band lower than the acoustic band. However, the frequency band of the vibration to be detected is not limited to this, and may be set as appropriate according to the structure of the vehicle 100 and the required passenger protection performance. That is, 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 frontal collision, and the frequency band of the low-frequency vibrations is a deceleration generated in the vehicle 100 by the frontal collision. If it is possible to capture.
In the above embodiment, the acoustic envelope Se (t) is calculated from the acoustic data Sa (t) as the first calculation value, and this acoustic envelope Se (t) is used for collision determination. However, the present invention is not limited to this, and other first calculation values (for example, average values) may be calculated from the acoustic data Sa (t).

  DESCRIPTION OF SYMBOLS 1, 1A, 1B ... SRS unit (vehicle collision determination apparatus), 2 ... Air bag (occupant protection apparatus), 11 ... Acoustic sensor (1st vibration sensor), 12 ... Acceleration sensor (2nd vibration sensor), 13, 16 ... Main collision determination unit (collision determination unit), 13a, 16a ... First calculation unit (first calculation unit), 13b, 16b ... Second calculation unit (second calculation unit), 13c ... Map determination unit (map determination unit) ), 14... Safing determination unit (safety determination unit), 15... AND unit (final determination unit), 16 c... First comparison unit (threshold determination unit), 16 d. ... AND section (threshold judgment means), 20 ... vibration sensor (vibration detection means), 21 ... BPF (first extraction means), 22 ... LPF (second extraction means), 100 ... vehicle

Claims (8)

Vibration detecting means for detecting high-frequency vibration in the acoustic band generated in the vehicle at the time of collision and low-frequency vibration in a band lower than the acoustic band;
A collision determination means for determining whether or not a collision requiring activation of an occupant protection device has occurred based on the detection results of the high-frequency vibration and the low-frequency vibration;
The collision determination means calculates a first calculation value based on the detection result of the high frequency vibration, calculates a second calculation value based on the detection result of the low frequency vibration, and the second calculation value is a predetermined threshold value. In the following cases, it is determined that no collision has occurred regardless of the magnitude of the first calculation value. The vibration detection means includes
A first vibration sensor that detects a vibration in a frequency band of 5 kHz to 20 kHz as the high-frequency vibration;
The vehicle collision determination device according to claim 1, further comprising: a second vibration sensor that detects vibration in a frequency band of 0 Hz to 400 Hz as the low frequency vibration. The vibration detection means detects broadband vibration including the high frequency vibration and low frequency vibration,
First extraction means for extracting the high-frequency vibration from the broadband vibration detected by the vibration detection means;
The vehicle collision determination device according to claim 1, further comprising: a second extraction unit that extracts the low-frequency vibration from the broadband vibration detected by the vibration detection unit. The first extraction means extracts a vibration in a frequency band of 5 kHz to 20 kHz as the high-frequency vibration from the broadband vibration,
4. The vehicle collision determination device according to claim 3, wherein the second extraction unit extracts a vibration in a frequency band of 0 Hz to 400 Hz as the low frequency vibration from the broadband vibration. The collision determination means includes
First calculation means for calculating an envelope of the high-frequency vibration as the first calculation value;
Second calculating means for calculating an integrated value of the low frequency vibration as the second calculated value;
On the two-dimensional map having the envelope as the first axis and the integral value as the second axis, the envelope and the integral value calculated by the first calculation means and the second calculation means have a two-dimensional collision determination threshold value. When it exceeds, it is determined that a collision that requires activation of the occupant protection device has occurred, and when the integral value is less than or equal to the two-dimensional collision determination threshold, the collision is performed regardless of the size of the envelope. The vehicle collision determination device according to any one of claims 1 to 4, further comprising: a map determination unit that determines that no occurrence has occurred. The collision determination means includes
First calculation means for calculating an envelope of the high-frequency vibration as the first calculation value;
Second calculating means for calculating an integrated value of the low frequency vibration as the second calculated value;
When the envelope exceeds a first collision determination threshold value and the integral value exceeds a second collision determination threshold value, it is determined that a collision requiring activation of the occupant protection device has occurred, while the integral value is 5. A threshold determination unit that determines that no collision has occurred regardless of the size of the envelope when the second collision determination threshold is less than or equal to the second collision determination threshold. The vehicle collision determination device according to claim 1.   The vehicle collision determination device according to claim 5 or 6, wherein the first calculation means calculates an absolute value envelope of the high-frequency vibration. Safing determination means for performing safing determination based on the detection result of the low frequency vibration;
Final determination means for determining whether or not a collision requiring the activation of the occupant protection device has finally occurred based on the collision determination result of the collision determination means and the safing determination result of the safing determination means; The vehicle collision determination device according to any one of claims 1 to 7, further comprising:

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