Collision mode prediction device and occupant protectant system

Abstract

To provide an art which can predict a collision mode of a vehicle and another vehicle.SOLUTION: In a collision mode prediction device, a first acquisition unit 36 acquires position information of an own vehicle. A second acquisition unit 38 acquires position information of another vehicle. When there is a possibility of a collision between the own vehicle and the other vehicle, a prediction unit 40 predicts a collision mode between the own vehicle and the other vehicle on the basis of the position information of the vehicle and the position information of the other vehicle.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a collision form prediction device and an occupant protection system.

Background Art

[0002] Patent Document 1 discloses a collision form determination device including left and right front sensors attached to the left and right sides of the front of a vehicle and detecting left and right decelerations in the front-rear direction. In this device, using the left and right decelerations detected by the left and right front sensors, it is detected that the vehicle has entered a collision state, and it is determined whether the collision is a symmetric collision such as a head-on collision or an asymmetric collision.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technology of Patent Document 1, two acceleration sensors are provided as the left and right front sensors, but it is conceivable to reduce the number of acceleration sensors to one for cost reduction. However, the collision form cannot be determined with a single acceleration sensor.

[0005] An object of the present invention is to provide a technology capable of predicting the collision form between a host vehicle and another vehicle.

Means for Solving the Problems

[0006] To solve the above problems, a collision form prediction device according to an aspect of the present invention includes a first acquisition unit that acquires position information of a host vehicle, a second acquisition unit that acquires position information of another vehicle, and a prediction unit that predicts a collision form between the host vehicle and the other vehicle based on the position information of the host vehicle and the position information of the other vehicle when there is a possibility of a collision between the host vehicle and the other vehicle.

[0007] Another aspect of the present invention is an occupant protection system. This occupant protection system includes a first acquisition unit that acquires position information of the host vehicle, a second acquisition unit that acquires position information of other vehicles, and a prediction unit that predicts a collision form between the host vehicle and other vehicles based on the position information of the host vehicle and the position information of other vehicles when there is a possibility of a collision between the host vehicle and other vehicles. The system also includes an acceleration sensor installed at the center of the front part of the host vehicle, and a control unit that controls the operation of the airbag of the host vehicle based on the comparison result between the acceleration detected by the acceleration sensor and a threshold value set according to the predicted collision form.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a technique for predicting the collision form between the host vehicle and other vehicles.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0010] Figs. 1(a) and 1(b) are diagrams for explaining the operation of the occupant protection system according to the embodiment. Figs. 1(a) and 1(b) show a situation immediately before a head-on collision between a first vehicle 1a and a second vehicle 1b that is traveling toward the first vehicle 1a from the front direction of the first vehicle 1a while the first vehicle 1a is in motion. Hereinafter, the first vehicle 1a and the second vehicle 1b are collectively referred to as vehicle 1 as appropriate.

[0011] Figure 1(a) shows a situation where a symmetric collision is likely. Figure 1(b) shows a situation where an asymmetric collision is likely. A symmetric collision is called when substantially all of the front of the vehicle body of vehicle 1 collides with a collision object. A symmetric collision can also be called a full-wrap collision. Also, an asymmetric collision is called when a part of the front of the vehicle body of vehicle 1 collides with a collision object. An asymmetric collision can also be called an offset collision.

[0012] The first vehicle 1a is provided with a first occupant protection system 10a. The first occupant protection system 10a includes an acceleration sensor 14a and an airbag (not shown). The acceleration sensor 14a is attached to the central part of the front of the first vehicle 1a. The second vehicle 1b is provided with a second occupant protection system 10b. The second occupant protection system 10b includes an acceleration sensor 14b and an airbag (not shown). Hereinafter, the first occupant protection system 10a and the second occupant protection system 10b are collectively referred to as the occupant protection system 10 as appropriate.

[0013] The first occupant protection system 10a and the second occupant protection system 10b can communicate directly using vehicle-to-vehicle communication. The first occupant protection system 10a and the second occupant protection system 10b have the same configuration and functions. Therefore, hereinafter, the first occupant protection system 10a will be described. Note that the second occupant protection system 10b may perform occupant protection with a configuration and functions different from those of the first occupant protection system 10a as long as it can transmit the position information of the second vehicle 1b to the first vehicle 1a using vehicle-to-vehicle communication.

[0014] In the situations of Figures 1(a) and (b), the first occupant protection system 10a of the first vehicle 1a determines whether there is a possibility of colliding with the second vehicle 1b using a radar (not shown) or the like. When it is determined that there is a possibility of colliding with the second vehicle 1b, the first occupant protection system 10a acquires the position information of the second vehicle 1b from the second vehicle 1b by vehicle-to-vehicle communication before the collision.

[0015] Subsequently, before a collision, the first occupant protection system 10a identifies the positional relationship between the center 2a of the first vehicle 1a and the center 2b of the second vehicle 1b based on the position information of the first vehicle 1a and the position information of the second vehicle 1b. When the identified positional relationship meets a predetermined criterion, it predicts that the collision mode is a symmetric collision. When the identified positional relationship does not meet the criterion, the first occupant protection system 10a predicts that the collision mode is an asymmetric collision. Details regarding the criterion will be described later.

[0016] In the example of FIG. 1(a), the first occupant protection system 10a predicts a symmetric collision and sets the activation conditions of the airbag to conditions suitable for a symmetric collision before the collision. After the situation in FIG. 1(a), when the first vehicle 1a and the second vehicle 1b collide and the acceleration detected by the acceleration sensor 14a satisfies the activation conditions, the first occupant protection system 10a activates the airbag.

[0017] In the example of FIG. 1(b), the first occupant protection system 10a predicts an asymmetric collision and sets the activation conditions of the airbag to conditions suitable for an asymmetric collision before the collision. After the situation in FIG. 1(b), when the first vehicle 1a and the second vehicle 1b collide and the acceleration detected by the acceleration sensor 14a satisfies the activation conditions, the first occupant protection system 10a activates the airbag.

[0018] Thus, according to the embodiment, it is possible to predict the collision mode between the host vehicle and another vehicle before the collision based on position information without using acceleration. Therefore, it is not necessary to install two acceleration sensors at the front of the vehicle 1 and determine the collision mode based on the difference in accelerations on the left and right. With one acceleration sensor 14a at the front of the vehicle 1, the airbag can be appropriately deployed according to the predicted collision mode. Hereinafter, the embodiment will be described in more detail. Hereinafter, the first vehicle 1a in FIGS. 1(a) and (b) will also be referred to as the host vehicle, and the second vehicle 1b will also be referred to as another vehicle.

[0019] FIG. 2 is a block diagram showing the functional configuration of the occupant protection system 10 of the embodiment. The occupant protection system 10 includes an external sensor 12, an acceleration sensor 14, a GNSS (Global Navigation Satellite System) receiver 16, a communication unit 18, an airbag ECU (Electronic Control Unit) 20, and an occupant protection device 22.

[0020] The external sensor 12 detects targets such as moving objects and obstacles based on reflected radio waves of radio waves transmitted to the periphery of the host vehicle. The external sensor 12 includes, for example, a laser radar or a millimeter-wave radar. When the external sensor 12 is a millimeter-wave radar, it transmits and receives frequency-modulated radar waves in the millimeter-wave band to detect targets located in front of and on the front side of the host vehicle, and based on the detection results, generates information about the targets such as the position and speed of the targets. The external sensor 12 may include a camera that images the front and the front side of the host vehicle instead of or in addition to the radar, and may generate information about the targets based on the captured image. The external sensor 12 outputs information about the detected targets to the airbag ECU 20.

[0021] The acceleration sensor 14 is for collision detection and is installed at the center of the front part of the host vehicle. For example, the acceleration sensor 14 is fixed to the center of the upper member of the radiator support. The acceleration sensor 14 detects the acceleration in the vehicle longitudinal direction and outputs the detected acceleration information to the airbag ECU 20. Hereinafter, the acceleration in the vehicle rear direction is set as a positive value. The acceleration detected by the acceleration sensor 14 is used for determining whether to deploy the airbag.

[0022] In the occupant protection system 10, in addition to the acceleration sensor 14, no acceleration sensor for collision detection is provided at the front part of the host vehicle. Since only one acceleration sensor 14 for collision detection needs to be provided at the front part of the host vehicle, the cost of the acceleration sensor can be reduced as compared with a known configuration in which two acceleration sensors are provided on the left and right of the front part of the host vehicle.

[0023] Note that the occupant protection system 10 may include a known floor sensor (not shown) installed on the floor that constitutes the passenger compartment of the host vehicle. The floor sensor also detects the acceleration in the longitudinal direction of the vehicle and outputs the detected acceleration information to the airbag ECU 20. The acceleration detected by the floor sensor may also be used for determining whether to deploy the airbag.

[0024] The GNSS receiver 16 receives signals from satellites and periodically derives the position of the host vehicle based on the received signals. The position of the host vehicle includes latitude and longitude. The GNSS receiver 16 outputs the derived position information to the airbag ECU 20. The GNSS receiver 16 may include, for example, a GPS (Global Positioning System) receiver.

[0025] The communication unit 18 exchanges information with the communication units of other vehicles through vehicle-to-vehicle communication using infrared lasers or radio waves. The communication unit 18 receives the position information of the host vehicle derived by the GNSS receiver 16 via the airbag ECU 20 and transmits it to the communication units of other vehicles. The transmitted position information is attached with a vehicle ID for identifying the vehicle that is the source. Also, the communication unit 18 receives the position information of the other vehicle from the communication unit of the other vehicle and outputs the received position information to the airbag ECU 20. The position information of the other vehicle is attached with a vehicle ID for identifying the other vehicle.

[0026] Note that the communication unit 18 may exchange position information with the communication units of other vehicles via a server device (not shown).

[0027] The occupant protection device 22 has an airbag 24 that can be deployed in the passenger compartment of the host vehicle. When an activation signal is supplied from the airbag ECU 20, the occupant protection device 22 activates the airbag 24. Various known configurations can be used as the occupant protection device 22.

[0028] The airbag ECU 20 includes a collision form prediction unit 30 and a control unit 32. The airbag ECU 20 can also be called a control device. The collision form prediction unit 30 includes a determination unit 34, a first acquisition unit 36, a second acquisition unit 38, and a prediction unit 40. The collision form prediction unit 30 corresponds to a collision form prediction device.

[0029] In terms of hardware, the configuration of the airbag ECU 20 can be realized by the CPU, memory, and other LSIs of any computer, and in terms of software, it can be realized by a program loaded in the memory, etc. Here, however, the functional blocks realized by their cooperation are depicted. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

[0030] Based on the information about the target supplied from the external sensor 12 and the vehicle information of the host vehicle, the determination unit 34 derives the collision time between the host vehicle and another vehicle. The vehicle information of the host vehicle includes speed, etc., and is acquired from various in-vehicle sensors (not shown). As the collision time, for example, TTC (Time To Collision) etc. can be used. The determination unit 34 determines whether there is a possibility of collision between the host vehicle and another vehicle based on TTC etc., and outputs the determination result to the first acquisition unit 36, the second acquisition unit 38, and the prediction unit 40. The possibility of collision is, for example, the possibility of a frontal collision. Various known techniques can be used for the determination of the possibility of collision.

[0031] When the determination unit 34 determines that there is a possibility of collision between the host vehicle and another vehicle, the first acquisition unit 36 acquires the position information of the host vehicle from the GNSS reception unit 16, and supplies the acquired position information to the prediction unit 40.

[0032] The second acquisition unit 38 has, for example, position relationship information of a plurality of vehicles created by a known vehicle-to-vehicle communication technology. The position relationship information includes the position of the host vehicle and the position and vehicle ID information of other vehicles around the host vehicle. The second acquisition unit 38 periodically acquires the position information of the host vehicle from the GNSS reception unit 16, and periodically acquires the position information and vehicle ID of other vehicles from other vehicles around the host vehicle via the communication unit 18 by vehicle-to-vehicle communication, and periodically updates the position relationship information.

[0033] When it is determined by the determination unit 34 that there is a possibility of collision between the host vehicle and other vehicles, the second acquisition unit 38 acquires the position information of the other vehicles with a possibility of collision, and supplies the acquired position information to the prediction unit 40.

[0034] For example, when it is determined that there is a possibility of collision between the host vehicle and other vehicles, the second acquisition unit 38 estimates, based on the position relationship information, other vehicles with a possibility of collision located closest in front of the host vehicle, specifies the vehicle ID of the estimated other vehicle, and the communication unit 18 transmits a request for position information by designating the specified vehicle ID. In this case, the communication unit of the vehicle having the specified vehicle ID transmits the latest position information in accordance with the received request. The communication unit 18 of the host vehicle receives the position information from the other vehicles with a possibility of collision, and the second acquisition unit 38 acquires the position information from the communication unit 18. In this case, even if the update frequency of the position relationship information is lower than the determination frequency of the collision possibility, the latest position information of the other vehicles with a possibility of collision can be acquired.

[0035] Alternatively, the update frequency of the position relationship information may be equal to the determination frequency of the collision possibility. When it is determined that there is a possibility of collision between the host vehicle and other vehicles, the second acquisition unit 38 may estimate other vehicles with a possibility of collision based on the position relationship information, and acquire the position information of the estimated other vehicles from the position relationship information. In this case, since there is no need to communicate with other vehicles after it is determined that there is a possibility of collision, it becomes easier to acquire the latest position information of other vehicles with a possibility of collision in a shorter time.

[0036] The second acquisition unit 38 may acquire the position information of other vehicles that may collide by using other known vehicle-to-vehicle communication technologies. For example, the second acquisition unit 38 may not have the positional relationship information. When it is determined that there is a possibility of collision between the host vehicle and other vehicles, the communication unit 18 may transmit a request for position information in front of the host vehicle without specifying the destination vehicle by using an infrared laser. The direction and range for transmitting the request can be appropriately determined by experiments or simulations. The communication unit of the vehicle that has received the request transmits the latest position information according to the received request.

[0037] When there is a possibility of collision between the host vehicle and other vehicles, the prediction unit 40 predicts the collision form between the host vehicle and other vehicles before the host vehicle and other vehicles collide, based on the position information of the host vehicle acquired by the first acquisition unit 36 and the position information of the other vehicles acquired by the second acquisition unit 38, and outputs the prediction result to the control unit 32.

[0038] When the positional relationship between the center of the host vehicle and the center of the other vehicle specified based on the position information of the host vehicle and the position information of the other vehicle satisfies the criterion, the prediction unit 40 predicts that the collision form is a symmetric collision.

[0039] As shown in FIG. 1(a), for example, when the center 2b of the other vehicle is located within a region A1 having a predetermined width L1 passing through the center 2a of the host vehicle in the longitudinal direction of the vehicle, the prediction unit 40 determines that the positional relationship between the center 2a of the host vehicle and the center 2b of the other vehicle satisfies the criterion. The region A1 is the region between the two broken lines in FIG. 1(a) and is a rectangular region extending parallel to the longitudinal direction of the vehicle. The center 2a of the host vehicle is located at the center in the vehicle width direction of the region A1.

[0040] The predetermined width L1 is narrower than the vehicle width of the host vehicle. The predetermined width L1 can be appropriately determined by experiments or simulations according to the collision range that should be a symmetric collision.

[0041] When the positional relationship between the center of the host vehicle and the center of the other vehicle does not satisfy the criterion, the prediction unit 40 predicts that the collision form is an asymmetric collision.

[0042] As shown in FIG. 1(b), for example, when the center 2b of the other vehicle is not located within the region A1 having a predetermined width L1 passing through the center 2a of the host vehicle in the vehicle longitudinal direction, the prediction unit 40 determines that the positional relationship between the center 2a of the host vehicle and the center 2b of the other vehicle does not satisfy the standard.

[0043] Returning to FIG. 2, the control unit 32 controls the operation of the airbag 24 of the host vehicle based on the comparison result between the acceleration detected by the acceleration sensor 14 and a threshold value set according to the collision form predicted by the prediction unit 40.

[0044] When the collision form is predicted to be a symmetric collision, the control unit 32 sets the threshold value to a first threshold value, and when the acceleration detected by the acceleration sensor 14 becomes equal to or greater than the first threshold value, the control unit 32 operates the airbag 24. Thereby, the airbag 24 is deployed.

[0045] When the collision form is predicted to be an asymmetric collision, the control unit 32 sets the threshold value to a second threshold value, and when the acceleration detected by the acceleration sensor 14 becomes equal to or greater than the second threshold value, the control unit 32 operates the airbag 24. The second threshold value is different from the first threshold value and is, for example, smaller than the first threshold value.

[0046] In an asymmetric collision, the time waveform of the acceleration at the time of collision detected by the acceleration sensor 14 is different from that in the case of a symmetric collision. The peak value of the time waveform of the acceleration becomes smaller than that in the case of a symmetric collision, and the rise of the time waveform of the acceleration may be slower than that in the case of a symmetric collision. Therefore, in an asymmetric collision, the time from the moment of collision until the acceleration reaches the first threshold value may be longer than that in the case of a symmetric collision. In the embodiment, since the second threshold value is smaller than the first threshold value, the timing of operating the airbag 24 in the case of an asymmetric collision can be advanced compared to the case of using the first threshold value. Therefore, even in the case of an asymmetric collision, the time from the moment of collision until the airbag 24 starts to deploy can be made equal to that in the case of a symmetric collision.

[0047] The initial value of the threshold may be the first threshold. Even when the collision mode has not been predicted, when the acceleration detected by the acceleration sensor 14 is equal to or greater than the first threshold, the control unit 32 activates the airbag 24. Thereby, even when the prediction unit 40 cannot predict the collision mode due to the inability to obtain the position information of the other vehicle, etc., the airbag 24 can be deployed.

[0048] Note that the control unit 32 may vary the operating conditions of the airbag 24 according to whether the predicted collision mode is a symmetric collision or an asymmetric collision, and other known operating conditions may also be adopted.

[0049] Next, the overall operation of the collision mode prediction unit 30 with the above configuration will be described. FIG. 3 is a flowchart showing the operation of the collision mode prediction unit 30 in FIG. 2. Note that, in parallel with the processing in FIG. 3, the process of determining whether to activate the airbag 24 by the control unit 32 is periodically repeated at a predetermined cycle.

[0050] The determination unit 34 determines whether there is a possibility of collision between the host vehicle and the other vehicle (S10). If there is no possibility of collision (N in S10), the determination unit 34 returns to the process of S10. When there is a possibility of collision (Y in S10), the first acquisition unit 36 acquires the position information of the host vehicle (S12), the second acquisition unit 38 acquires the position information of the other vehicle (S14), and the prediction unit 40 determines whether the positional relationship between the host vehicle and the other vehicle satisfies the criterion (S16). When the positional relationship between the host vehicle and the other vehicle satisfies the criterion (Y in S16), the prediction unit 40 predicts a symmetric collision (S18), and the collision mode prediction unit 30 ends the process. When the positional relationship between the host vehicle and the other vehicle does not satisfy the criterion (N in S16), the prediction unit 40 predicts an asymmetric collision (S20), and the collision mode prediction unit 30 ends the process.

[0051] As described above, the present invention has been described based on the embodiments. It should be understood by those skilled in the art that the embodiments are merely examples, and various modifications are possible for the combination of each component and each processing process, and such modifications are also within the scope of the present invention.

[0052] For example, in addition to the positional relationship between the center of the host vehicle and the center of the other vehicle immediately before the collision, the prediction unit 40 may predict the collision form based on the traveling direction of the host vehicle and the traveling direction of the other vehicle immediately before the collision. In this case, when it is determined that there is a possibility of collision between the host vehicle and the other vehicle, the first acquisition unit 36 further acquires information on the traveling direction of the host vehicle from the GNSS reception unit 16, and supplies the acquired traveling direction information to the prediction unit 40 as well. When it is determined that there is a possibility of collision between the host vehicle and the other vehicle, the second acquisition unit 38 further acquires information on the traveling direction of the other vehicle with a possibility of collision, and supplies the acquired traveling direction information to the prediction unit 40 as well. When the positional relationship between the center of the host vehicle and the center of the other vehicle satisfies the standard, and the traveling direction of the host vehicle and the traveling direction of the other vehicle satisfy another standard, the prediction unit 40 predicts that the collision form is a symmetric collision. For example, when the traveling direction of the other vehicle deviates from the traveling direction of the host vehicle by less than a predetermined angle, the prediction unit 40 determines that the traveling direction of the host vehicle and the traveling direction of the other vehicle satisfy another standard. The predetermined angle can be appropriately determined by experiments or simulations. When the positional relationship between the center of the host vehicle and the center of the other vehicle does not satisfy the standard, or when the traveling direction of the host vehicle and the traveling direction of the other vehicle do not satisfy another standard, the prediction unit 40 predicts that the collision form is an asymmetric collision. According to this modification example, even if the positional relationship between the center of the host vehicle and the center of the other vehicle satisfies the standard, when there is a high possibility that the other vehicle collides obliquely with the host vehicle, it can be predicted as an asymmetric collision, so it is easy to improve the prediction accuracy of the collision form.

Explanation of Signs

[0053] 10… Occupant protection system, 12… External sensor, 14, 16… GNSS reception unit, 18… Communication unit, 20… Airbag ECU, 22… Occupant protection device, 24… Airbag, 30… Collision form prediction unit, 32… Control unit, 34… Determination unit, 36… First acquisition unit, 38… Second acquisition unit, 40… Prediction unit.

Claims

1. A first acquisition unit that acquires the position information of the host vehicle, A second acquisition unit that acquires the position information of other vehicles, A prediction unit that predicts the collision form between the host vehicle and other vehicles based on the position information of the host vehicle and the position information of other vehicles when there is a possibility of collision between the host vehicle and other vehicles, A collision form prediction device characterized by comprising the above.

2. The prediction unit, When the positional relationship between the center of the host vehicle and the center of the other vehicle specified based on the position information of the host vehicle and the position information of the other vehicle satisfies a predetermined criterion, predicts that the collision form is a symmetric collision, When the positional relationship between the center of the host vehicle and the center of the other vehicle does not satisfy the criterion, predicts that the collision form is an asymmetric collision, The collision form prediction device according to Claim 1, characterized by the above.

3. The prediction unit determines that the positional relationship between the center of the host vehicle and the center of the other vehicle satisfies the criterion when the center of the other vehicle is located within a region having a predetermined width passing through the center of the host vehicle in the vehicle longitudinal direction. The collision form prediction device according to Claim 2, characterized by the above.

4. A first acquisition unit that acquires the position information of the host vehicle, A second acquisition unit that acquires the position information of other vehicles, A prediction unit that predicts the collision form between the host vehicle and other vehicles based on the position information of the host vehicle and the position information of other vehicles when there is a possibility of collision between the host vehicle and other vehicles, An acceleration sensor installed at the center of the front part of the host vehicle, A control unit that controls the operation of the airbag of the host vehicle based on the comparison result between the acceleration detected by the acceleration sensor and a threshold value set according to the predicted collision form, An occupant protection system characterized by comprising the above.

5. Except for the acceleration sensor, an acceleration sensor for collision detection is not provided at the front part. The occupant protection system according to Claim 4, characterized by the above.

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