JP2019027833A - Collision detection device - Google Patents

Abstract

To provide a collision detection device capable of detecting the underride collision at an earlier stage.SOLUTION: A collision detection device 1 includes: an acquisition part 21; and a collision determination part 23. The acquisition part 21 is provided in the front part of a vehicle body and acquires a sensor value of a front sensor 10 which detects the acceleration in a vertical direction of a vehicle. The collision determination part 23 determines whether or not the collision is the underride accident based on the sensor value acquired by the acquisition part 21.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a collision detection device.

  Conventionally, when a collision of a vehicle is detected by a collision detection device, for example, there is a technique for protecting an occupant by deploying an airbag or the like. The collision detection device detects a collision based on, for example, an acceleration sensor arranged near the center of the vehicle called a “floor sensor” and an acceleration sensor arranged in the front part of the vehicle called a “front sensor” (for example, patents). Reference 1).

  Collision modes detected by the collision detection device include, for example, a full lap collision that is a full surface collision of a vehicle, an offset collision that collides with one side of the front of the vehicle, an underride collision that collides so as to enter under a rear portion of a truck, etc. .

JP 2001-247003 A

  However, the conventional technology has room for improvement in terms of detecting an underride collision earlier. Specifically, in the case of an underride collision, the impact transmitted to the floor sensor is slower than other collision modes, and accordingly, the collision detection may be delayed.

  This invention is made | formed in view of the above, Comprising: It aims at providing the collision detection apparatus which can detect an underride collision at an early stage.

  In order to solve the above-described problems and achieve the object, a collision detection apparatus according to the present invention includes an acquisition unit and a collision determination unit. The acquisition unit is provided at a front portion of the vehicle body, and acquires a sensor value of a front sensor that detects acceleration in the vertical direction of the vehicle. The collision determination unit determines whether it is an underride collision based on the sensor value acquired by the acquisition unit.

  According to the present invention, an underride collision can be detected earlier.

FIG. 1A is a diagram illustrating an outline of a collision detection method according to the embodiment. FIG. 1B is a diagram illustrating an outline of the collision detection method according to the embodiment. FIG. 2 is a block diagram illustrating a configuration of the occupant protection system according to the embodiment. FIG. 3 is an explanatory diagram of threshold information. FIG. 4 is a diagram illustrating processing contents of the collision determination unit. FIG. 5 is a diagram illustrating processing contents of the collision determination unit. FIG. 6 is a diagram illustrating processing contents of the collision determination unit. FIG. 7 is a diagram illustrating processing contents of the activation unit. FIG. 8 is a flowchart illustrating a processing procedure of detection processing executed by the collision detection device according to the embodiment.

  Hereinafter, an embodiment of a collision determination device disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment.

  First, the outline | summary of the collision detection method which the collision determination apparatus which concerns on embodiment performs using FIG. 1A and FIG. 1B is demonstrated. 1A and 1B are diagrams illustrating an overview of a collision detection method according to an embodiment. FIG. 1A shows the positional relationship between the vehicle C and the object 100.

  The object 100 is, for example, a truck or the like, and has a relatively large space 100a between the object 100 and the road surface. Note that the object 100 is not limited to a moving body such as a truck, and may be a stationary object in which a space 100a into which the front part of the vehicle C enters is formed.

  The collision detection apparatus 1 according to the embodiment is mounted on the vehicle C and executes the collision detection method according to the embodiment. Further, the vehicle C is provided with two acceleration sensors 10 and 11. The acceleration sensor 10 is provided on the entire vehicle body and detects, for example, an impact associated with a collision of the vehicle C as an acceleration.

  Further, as shown in FIG. 1A, the acceleration sensor 10 is a three-axis acceleration capable of detecting acceleration in the X-axis direction that is the front-rear direction of the vehicle C, the Y-axis direction that is the left-right direction, and the Z-axis direction that is the vertical direction. It is a sensor. Hereinafter, the acceleration sensor 10 may be referred to as a front sensor 10.

  The acceleration sensor 11 is an acceleration sensor built in an airbag ECU (Electronic Control Unit) provided on the floor near the center of the vehicle C, for example. The acceleration sensor 11 detects the acceleration in the front-rear direction of the vehicle C. The acceleration sensor 11 may be an acceleration sensor that detects acceleration in the left-right direction and the up-down direction in addition to the front-rear direction of the vehicle C.

  Hereinafter, the acceleration sensor 11 may be referred to as a floor sensor 11. The acceleration sensor 11 is not limited to being provided near the center of the vehicle C, and may be an acceleration sensor provided behind the vehicle C rather than the front sensor 10.

  Assume that the vehicle C collides with the object 100 in the positional relationship shown in FIG. In such a case, the front portion of the vehicle C collides in the form of a so-called underride collision that collides so as to enter the space 100a of the object 100 while rubbing the upper surface of a bonnet or the like.

  Specifically, due to an underride collision, the upper part of the hood, driver's seat, etc. of the vehicle C becomes a collision area that directly collides with the object 100, and the lower part of the wheel, etc. of the vehicle C does not collide directly with the object 100. It becomes. That is, it can be said that the non-collision region is a region where the impact is transmitted with a delay after the impact is transmitted to the collision region.

  Here, a conventional collision detection method will be described. In the conventional collision detection method, when an impact is detected by both the front sensor and the floor sensor, for example, an airbag or the like is deployed.

  However, in the case of an underride collision, it takes a relatively long time from when the impact is detected by the front sensor in the vicinity of the collision area until the impact is detected by the floor sensor in the non-collision area. For this reason, compared with other collision modes such as a full lap collision, there is a possibility that the collision detection may be delayed in the underride collision, so there is room for improvement in terms of detecting the underride collision earlier.

  Therefore, in the collision detection method according to the embodiment, an underride collision is detected by the front sensor 10 regardless of the floor sensor 11. Specifically, it is determined based on the acceleration in the vertical direction (Z-axis) that is the sensor value of the front sensor 10 whether or not it is an underride collision.

  As illustrated in FIG. 1B, in the collision detection method according to the embodiment, when the acceleration in the vertical direction (Z-axis) becomes equal to or greater than a predetermined threshold (Z-axis threshold), it is determined that an underride collision has occurred. In the collision detection method according to the embodiment, an underride collision can be determined in consideration of acceleration in the front-rear direction (X-axis), which will be described later.

  In other collision modes such as a full lap collision, the acceleration in the front-rear direction increases and the acceleration in the vertical direction does not increase so much, and therefore does not exceed the Z-axis threshold. That is, in the collision detection method according to the embodiment, the front sensor 10 can make a determination regardless of the floor sensor 11 by detecting the vertical acceleration peculiar to the underride collision. Therefore, in the collision detection method according to the embodiment, an underride collision can be detected earlier than in the related art.

  In the collision detection method according to the embodiment, when an underride collision is detected, a threshold value for activation in an occupant protection device such as an airbag is lowered. This point will be described later with reference to FIG.

  Next, the configuration of the occupant protection system S including the collision detection device 1 according to the embodiment will be described in detail with reference to FIG. FIG. 2 is a block diagram illustrating a configuration of the occupant protection system S according to the embodiment. As shown in FIG. 2, the occupant protection system S according to the embodiment includes a front sensor 10, a floor sensor 11, a collision detection device 1, and an airbag 20.

  The airbag 20 is, for example, a bag provided in a driver's seat or a passenger seat of the vehicle C, and is an occupant protection device that protects the occupant from impacts such as a collision by instantaneously inflating the bag. The airbag 20 is an example, and may be an occupant protection device such as a pretensioner that removes slack in the seat belt at the time of collision.

  The collision detection device 1 according to the embodiment includes a control unit 2 and a storage unit 3. The control unit 2 includes an acquisition unit 21, a calculation unit 22, a collision determination unit 23, and an activation unit 24. The storage unit 3 stores threshold information 31.

  Here, the collision detection apparatus 1 includes, for example, a computer having various functions such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a HDD (Hard Disk Drive), an input / output port, and the like. including.

  The CPU of the computer functions as the acquisition unit 21, the calculation unit 22, the collision determination unit 23, and the activation unit 24 of the control unit 2, for example, by reading and executing a program stored in the ROM.

  In addition, at least one or all of the acquisition unit 21, the calculation unit 22, the collision determination unit 23, and the activation unit 24 of the control unit 2 are used as hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). Can also be configured.

  The storage unit 3 corresponds to, for example, a RAM or an HDD. The RAM and HDD can store threshold information 31 and information on various programs. The collision detection apparatus 1 may acquire the above-described program and various information via another computer or a portable recording medium connected via a wired or wireless network.

  The threshold information 31 is information including a threshold that serves as a determination criterion for a collision determination unit 23 and an activation unit 24 described later. Here, the threshold information 31 will be described with reference to FIG. FIG. 3 is an explanatory diagram of the threshold information 31.

  As illustrated in FIG. 3, the threshold information 31 includes items such as “sensor type”, “axial direction”, and “threshold”. “Sensor type” is information indicating the type of the acceleration sensor. “Axial direction” indicates the detection direction of the acceleration sensor. The “threshold value” indicates a threshold value of the sensor value in each axis direction. The “threshold value” is a value set in advance from data such as a collision experiment, for example.

  For example, in the example illustrated in FIG. 3, the sensor type is “front”, that is, in the front sensor 10, the threshold value of the sensor value in the X-axis direction that is the front-rear direction of the vehicle C is “TH1”.

  In the example illustrated in FIG. 3, in the front sensor 10 having the sensor type “front”, the threshold value of the sensor value in the Z-axis direction that is the vertical direction of the vehicle C is “TH2”. In other words, the threshold values “TH1” and “TH2” of the front sensor 10 are threshold values that serve as criteria for determining an underride collision.

  Further, as shown in FIG. 3, the sensor type is “floor”, that is, in the floor sensor 11, the threshold value of the sensor value in the X-axis direction that is the front-rear direction of the vehicle C is “TH3”. In other words, the threshold value “TH3” is a threshold value that serves as a reference for determining whether the airbag 20 is deployed.

  That is, the collision determination unit 23 and the activation unit 24 which will be described later use the threshold information 31 to determine whether or not there is an underride collision and determine whether the airbag 20 is deployed.

  The threshold values “TH1” and “TH2” of the front sensor 10 may be the same value (different detection directions) or different values. In FIG. 3, the threshold value in the Y-axis direction, which is the left-right direction, is “None”.

  The threshold information 31 shown in FIG. 3 includes the threshold values of the front sensor 10 and the floor sensor 11 at the time of an underride collision, but may further include threshold values of each sensor at the time of a full lap collision or an offset collision, for example.

  The control unit 2 determines the presence or absence of an underride collision based on the sensor values of the front sensor 10 and the floor sensor 11, and performs activation control of the airbag 20 based on the determination result.

  The acquisition unit 21 is provided in the front part of the vehicle body, and acquires the sensor value of the front sensor 10 that detects acceleration in the vertical direction of the vehicle C. Specifically, the acquisition unit 21 acquires accelerations in the vertical direction, the front-rear direction, and the left-right direction of the vehicle C as sensor values, and outputs them to the collision determination unit 23 and the calculation unit 22.

  Note that the acquisition unit 21 may pass the acquired sensor value through a low-pass filter to remove noise components and output the result to each unit. Thereby, determination accuracy and calculation accuracy can be improved in the subsequent processing.

  The calculation unit 22 calculates an integral value of sensor values in the front sensor 10 and the floor sensor 11. In “integral value calculation”, the calculation method can be selected from 1) total integration by constant switching, 2) interval integration, and 3) total integration with start / end conditions.

  1) is a total integration operation in which the previously calculated integral value is weighted, where the current time is t and the weight is k, the integral value (t) = k × integral value (t−1) + It can be calculated by acceleration (t). For example, k is weighted so as to increase when acceleration (t) ≧ 2G, and is weighted so as to decrease when acceleration (t) <2G.

  2) is an integral calculation for a predetermined interval in the past of acceleration (t), and the predetermined interval is, for example, about 100 milliseconds. Since the collision is said to end in about 100 to 150 milliseconds, 2) corresponds to the total integration calculation at the time of the collision.

  3) is a simple integration operation with a start condition and an end condition. For example, the start condition is acceleration (t) ≧ 2G, and the integral value (t) = integral value (t−1) + acceleration (t) The calculation is started, and the calculation ends with an end condition / acceleration (t) <2G.

  In the above description, the integral value = deceleration has been described, but a movement amount may be used instead of the deceleration. The movement amount corresponds to the second-order integral value of acceleration.

  The collision determination unit 23 determines whether it is an underride collision based on the sensor value acquired by the acquisition unit 21. For example, when the acceleration in the Z-axis direction that is the vertical direction of the vehicle C is equal to or greater than the threshold value “TH2”, the collision determination unit 23 determines that it is an underride collision.

  The collision determination unit 23 may determine the presence or absence of an underride collision in consideration of the acceleration in the front-rear direction in addition to the vertical direction. That is, the collision determination unit 23 determines whether or not it is an underride collision based on the vertical and longitudinal accelerations of the vehicle C. Here, the details of this point will be described with reference to FIGS.

  4-6 is a figure which shows the processing content of the collision determination part 23. FIG. FIG. 4 shows the determination logic of the collision determination unit 23. As shown in FIG. 4, the collision determination unit 23 includes an AND gate G, and determines the presence or absence of an underride collision by a logical product operation.

  Specifically, the collision determination unit 23 determines whether or not the acceleration in the X-axis direction of the front sensor 10 is equal to or greater than the threshold “TH1”, and the acceleration in the Z-axis direction of the front sensor 10 is the threshold “TH2”. It is determined whether or not this is the case, and the determination result is input to the AND gate G.

  When the AND gate G receives a signal indicating that the acceleration in the X-axis direction is equal to or greater than the threshold value “TH1” and a signal indicating that the acceleration in the Z-axis direction is equal to or greater than the threshold value “TH2”, the AND gate G Determined to be a ride collision.

  Thereby, for example, it can be prevented that an impact in which only the acceleration in the vertical direction exceeds the threshold when a step is exceeded is erroneously determined as an underride collision.

  Further, as shown in FIG. 5, the collision determination unit 23 may consider the timing when the acceleration in the vertical direction and the front-rear direction become equal to or greater than a threshold value. FIG. 5 shows a determination map in which the vertical axis indicates acceleration and the horizontal axis indicates time. The time zero on the horizontal axis corresponds to the moment of collision.

  As shown in FIG. 5, the collision determination unit 23 determines the difference between the timing when the acceleration in the Z-axis direction is equal to or greater than the threshold “TH2” and the timing when the acceleration in the X-axis direction is equal to or greater than the threshold “TH1”. When D1 is within a predetermined time, it is determined that there is an underride collision.

  That is, the collision determination unit 23 performs the determination process by using the characteristic that the acceleration in the vertical direction and the front-rear direction of the vehicle C increases at the same time or slightly deviates during an underride collision. Thereby, since misjudgment can be reduced more, an underride collision can be detected reliably.

  In addition, although the collision determination part 23 performed the determination process by the timing difference D1 of an up-down direction and the front-back direction, you may consider the integration value of the sensor value in the floor sensor 11 not only this.

  Specifically, the collision determination unit 23 underperforms when the integral value of the sensor value in the floor sensor 11 calculated by the calculation unit 22 is not more than a predetermined value and the sensor value of the front sensor 10 is not less than a threshold value. Determined to be a ride collision.

  This utilizes a difference in acceleration increase characteristics between an underride collision and another type of collision (such as a full lap collision). Specifically, in the underride collision, the acceleration increases at the front sensor 10 at the moment of the collision, while the floor sensor 11 has not yet received an impact and the acceleration has not increased so much.

  On the other hand, in the full lap collision, the acceleration is increased by the front sensor 10 at the moment of the collision, and the acceleration is also increased to some extent by the floor sensor 11.

  In other words, the collision determination unit 23 underperforms when the integrated value of the floor sensor 11 is equal to or less than a predetermined value, that is, when the sensor value of the front sensor 10 is equal to or greater than the threshold value during a period in which the acceleration of the floor sensor 11 has not yet increased. Determined to be a ride collision.

  In other words, when the sensor values of the floor sensor 11 and the front sensor 10 rise almost simultaneously, the collision determination unit 23 determines that the collision type is another collision type such as a full lap collision. Thus, by utilizing the integrated value of the floor sensor 11, the underride collision and other collision modes can be easily separated.

  The collision determination unit 23 uses an acceleration and time determination map as shown in FIG. 5. For example, the collision determination unit 23 performs a determination process using the vertical and forward acceleration determination maps as shown in FIG. 6. May be. FIG. 6 shows a determination map in which the vertical axis indicates the acceleration in the Z-axis direction and the horizontal axis indicates the acceleration in the X-axis direction.

  As illustrated in FIG. 6, the collision determination unit 23 determines an underride collision only in a region where the acceleration in the Z-axis direction is equal to or greater than the threshold “TH2” and the acceleration in the X-axis direction is equal to or greater than the threshold “TH1”. .

  That is, the collision determination unit 23 determines that the collision is an underride collision when the vertical acceleration is equal to or greater than the threshold “TH2” and the acceleration in the front-rear direction is equal to or greater than the threshold “TH1”.

  In this way, by detecting that the acceleration change peculiar to the underride collision, that is, the acceleration in the vertical direction and the front-rear direction exceeds the respective threshold values almost simultaneously, the underride collision can be reliably detected.

  Returning to FIG. 2, the activation unit 24 will be described. The activation unit 24 activates an occupant protection device such as the airbag 20 when the sensor value of the floor sensor 11 is equal to or greater than a predetermined threshold value. For example, the activation unit 24 decreases the threshold when the collision determination unit 23 determines that an underride collision has occurred. This point will be described with reference to FIG.

  FIG. 7 is a diagram illustrating processing contents of the activation unit 24. FIG. 7 shows a determination map used for determining the deployment of an occupant protection device such as the airbag 20. In the determination map shown in FIG. 7, the vertical axis indicates the acceleration that is the sensor value of the floor sensor 11, and the horizontal axis indicates time. Zero on the horizontal axis corresponds to the collision occurrence time.

  FIG. 7 shows three threshold values. The “high-speed threshold value” is a threshold value when a full-lap collision at a relatively high speed is detected. The “low speed threshold value” is a threshold value when a full lap collision at a relatively low speed is detected. The “URD threshold value” is a threshold value when an underride collision is detected. “URD threshold” is the threshold “TH3” of the threshold information 31 (see FIG. 3).

  The “high speed threshold” and the “low speed threshold” can be switched based on, for example, a sensor that detects the traveling speed of the vehicle C. Alternatively, switching can be performed based on the acceleration value in the front-rear direction of the front sensor 10, the detection time, or the like.

  As illustrated in FIG. 7, when the collision determination unit 23 determines that the activation unit 24 is an underride collision, the activation unit 24 deploys the airbag 20 with a URD threshold that is lower than the threshold of other collision modes such as a full lap collision. Make a decision.

  Thereby, since the airbag 20 can be rapidly deployed at the time of an underride collision, the safety of the passenger of the vehicle C can be improved.

  In the determination map of FIG. 7, time is used on the horizontal axis, but for example, an integrated value of sensor values in the floor sensor 11 may be used. Thereby, it is possible to prevent erroneous development of a situation in which acceleration increases instantaneously such as noise.

  Next, a processing procedure of processing executed by the collision detection device 1 according to the embodiment will be described with reference to FIG. FIG. 8 is a flowchart illustrating a processing procedure of detection processing executed by the collision detection device 1 according to the embodiment.

  As shown in FIG. 8, first, the acquisition unit 21 acquires a sensor value of the front sensor 10 that detects acceleration in the three-axis direction of the vehicle C (step S101). The triaxial directions are, for example, the vertical direction, the front-rear direction, and the left-right direction of the vehicle C.

  Subsequently, the control unit 2 acquires the sensor value of the floor sensor 11 (step S102). Note that the processing order of step S101 and step S102 may be interchanged.

  Subsequently, the calculation unit 22 calculates an integral value of the acquired sensor values in the floor sensor 11 (step S103). Subsequently, the collision determination unit 23 determines whether or not the acceleration in the vertical direction (Z-axis) in the front sensor 10 is equal to or greater than the threshold “TH2” (step S104).

  When the acceleration in the vertical direction (Z axis) in the front sensor 10 is equal to or greater than the threshold “TH2” (step S104, Yes), the collision determination unit 23 determines that the acceleration in the front and rear direction (X axis) in the front sensor 10 is the threshold “TH1. It is determined whether or not it is greater than or equal to (step S105).

  Subsequently, when the acceleration in the front-rear direction (X axis) of the front sensor 10 is equal to or greater than the threshold “TH1” (step S105, Yes), the collision determination unit 23 determines that the acceleration of both axes in the front sensor 10 is equal to or greater than the threshold. It is determined whether or not the difference in timing is within a predetermined time (step S106). Specifically, the collision determination unit 23 has a timing when the acceleration in the vertical direction becomes equal to or higher than the first threshold (TH2), and a timing when the acceleration in the front-rear direction becomes equal to or higher than the second threshold (TH1). It is determined whether or not the difference is within a predetermined time.

  Subsequently, the collision determination unit 23 determines that the integrated value of the floor sensor 11 is within a predetermined value when the difference between the timings when the accelerations of both axes in the front sensor 10 are equal to or greater than the threshold is within a predetermined time (step S106, Yes). It is determined whether or not (step S107).

  Subsequently, when the integrated value of the floor sensor 11 is within a predetermined value (step S107, Yes), the collision determination unit 23 determines that there is an underride collision (step S108) and ends the process.

  On the other hand, in Step S104, when the acceleration in the vertical direction (Z-axis) in the front sensor 10 is less than the threshold “TH2” (No in Step S104), the collision determination unit 23 uses other collision modes other than the underride collision. A determination process is performed (step S109), and the process ends.

  In step S105, when the acceleration in the front-rear direction (X axis) in the front sensor 10 is less than the threshold “TH1” (No in step S105), the collision determination unit 23 proceeds to step S109.

  In Step S106, when the difference between the timings when the accelerations of both axes in the front sensor 10 are equal to or greater than the threshold exceeds the predetermined time (No in Step S106), the collision determination unit 23 proceeds to Step S109.

  In Step S107, when the integrated value of the floor sensor 11 is not within the predetermined value (No in Step S107), the collision determination unit 23 proceeds to Step S109.

  As described above, the collision detection device 1 according to the embodiment includes the acquisition unit 21 and the collision determination unit 23. The acquisition unit 21 is provided in the front part of the vehicle body, and acquires the sensor value of the front sensor 10 that detects acceleration in the vertical direction of the vehicle C. The collision determination unit 23 determines whether it is an underride collision based on the sensor value acquired by the acquisition unit 21. Thereby, an underride collision can be detected earlier than before.

  In the above-described embodiment, the case where one front sensor 10 is provided in the vehicle C has been described, but a plurality of front sensors 10 may be provided in the vehicle C. In such a case, for example, it can be provided at the center and at the left and right of the front part of the vehicle body.

  Thereby, since it can be determined whether the entire front part of the vehicle body has entered the space 100a (see FIG. 1A) or one of the left and right parts has partially entered, for example, the airbag 20 can be placed between the driver seat and the passenger seat. The timing of deployment can be shifted. Therefore, the safety of the passenger can be further improved.

  In the above-described embodiment, the collision determination unit 23 may perform an underride collision determination process only while the vehicle C is traveling, for example. Thereby, while being able to suppress processing load, it can prevent erroneously detecting the impact accompanying opening and closing of a bonnet, for example.

  Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 1 Collision detection apparatus 2 Control part 3 Memory | storage part 10 Front sensor (acceleration sensor)
11 Floor sensor (acceleration sensor)
DESCRIPTION OF SYMBOLS 20 Airbag 21 Acquisition part 22 Calculation part 23 Collision determination part 24 Start-up part 31 Threshold information 100 Object C Vehicle S Crew protection system

Claims (6)

An acquisition unit that is provided in a front part of the vehicle body and acquires a sensor value of a front sensor that detects acceleration in a vertical direction of the vehicle;
A collision detection unit comprising: a collision determination unit that determines whether or not an underride collision is based on the sensor value acquired by the acquisition unit. An activating unit that activates an occupant protection device mounted on the vehicle when a sensor value of a floor sensor that detects acceleration and is provided above the front sensor is greater than or equal to a predetermined threshold;
The activation unit is
The collision detection device according to claim 1, wherein when the collision determination unit determines that the underride collision is detected, the threshold value is decreased. A calculation unit that calculates an integral value of sensor values in the floor sensor;
The collision determination unit
The underride collision is determined when the integral value calculated by the calculation unit is equal to or less than a predetermined value and the sensor value of the front sensor is equal to or greater than a predetermined threshold. 2. The collision detection device according to 2. The acquisition unit
Further acquiring acceleration in the longitudinal direction of the vehicle as a sensor value of the front sensor,
The collision determination unit
The collision detection device according to any one of claims 1 to 3, wherein it is determined whether the underride collision is based on the acceleration in the vertical direction and the front-rear direction. The collision determination unit
When the difference between the timing at which the vertical acceleration is equal to or higher than the first threshold and the timing at which the vertical acceleration is equal to or higher than the second threshold is within a predetermined time, the underride The collision detection device according to claim 4, wherein the collision detection device is determined to be a collision. The collision determination unit
5. The underride collision is determined when the vertical acceleration is equal to or greater than a first threshold and the longitudinal acceleration is equal to or greater than a second threshold at the same time. Or the collision detection apparatus of 5.

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