JP7500993B2 - Communication control device and program - Google Patents

Description

The present invention relates to a communication control device and a program.

Technologies have been researched to prevent vehicle collisions at junctions where multiple roads merge. For example, a technology is known in which a merging vehicle traveling on a branch road acquires the speed and position of a merging vehicle (main road vehicle) traveling on a main road using wide-area wireless communication or vehicle-to-vehicle communication, and calculates a driving plan for merging based on the speed and position of the main road vehicle.

Patent Documents 1 to 4 also disclose technologies for assisting vehicle merging. For example, Patent Document 1 discloses a technology that makes it easy to determine which main line vehicle a merging vehicle will merge with before merging. Patent Document 2 discloses a technology in which a merging vehicle and a merged vehicle communicate via a server, in which the server grasps the movement of the merged vehicle and determines how the merging vehicle will merge. Patent Document 3 discloses a technology in which a vehicle reduces the frequency of transmitting its own vehicle information when other vehicles are communicating with each other. Patent Document 4 discloses a technology in which, at a merging point, a vehicle that meets certain conditions among vehicles with which the vehicle can communicate is listed and communicated with.

JP 2017-207812 A JP 2017-117186 A JP 2017-146089 A JP 2017-196651 A

However, when each vehicle transmits packets, communication traffic increases in proportion to the vehicle density. When communication traffic increases, degradation of communication quality and packet loss occur.

The present invention has been made in consideration of the above problems, and the object of the present invention is to provide a new and improved communication control device and program that can reduce communication traffic for vehicle driving support.

In order to solve the above problems, according to one aspect of the present invention, a communication control device is provided that is mounted on a vehicle and includes a distance detection unit that detects both a forward inter-vehicle distance, which is the distance between the vehicle and a vehicle in front, and a rear inter-vehicle distance, which is the distance between the vehicle and a vehicle behind, a receiving unit that receives a response request packet from another vehicle traveling on a different road than the vehicle, and a response control unit that determines whether to respond to the response request packet based on whether the distance detected by the distance detection unit is below a threshold, wherein the response control unit determines to respond to the response request packet based on whether both the forward inter-vehicle distance and the rear inter-vehicle distance are below the threshold, and determines not to respond to the response request packet based on whether at least one of the forward inter-vehicle distance or the rear inter-vehicle distance exceeds the threshold . In order to solve the above problem, according to another aspect of the present invention, there is provided a communication control device mounted on a vehicle, the communication control device comprising: a distance detection unit that detects a distance between the vehicle and a vehicle ahead or a vehicle behind the vehicle; a receiving unit that receives a response request packet including area information indicating a response request area from another vehicle traveling on a different traveling path from the vehicle; and a response control unit that determines whether or not to respond to the response request packet, wherein the response control unit determines to respond to the response request packet when the vehicle corresponds to the rearmost vehicle in the response request area. The response control unit may also determine to respond to the response request packet when the vehicle corresponds to the leading vehicle in the response request area. The response control unit may determine whether or not to respond to the response request packet based on whether or not the distance detected by the distance detection unit is equal to or less than a threshold value when the vehicle does not correspond to either the leading vehicle or the rearmost vehicle in the response request area.

When the response control unit determines to respond to the response request packet, the response control unit may generate a response packet that includes location information of the vehicle.

The response packet may further include speed information of the vehicle and distance information indicating the distance detected by the distance detection unit.

The distance detection unit detects both a forward distance between the vehicle and the vehicle ahead, and a rear distance between the vehicle and the vehicle behind, and the response control unit may determine to respond to the response request packet if both the forward distance and the rear distance are equal to or less than the threshold, and may determine not to respond to the response request packet if at least one of the forward distance or the rear distance exceeds the threshold.

The response request packet may include area information indicating a response request area, and the conditions for the response control unit to determine that it should respond to the response request packet may include that the vehicle is included in the response request area.

The response control unit may determine that the vehicle is to respond to the response request packet if there is a possibility that the vehicle is the leading vehicle or the last vehicle in the response request area, regardless of whether the distance detected by the distance detection unit is equal to or less than a threshold value.

The vehicle may be traveling on a first roadway and the other vehicle may be traveling on a second roadway that merges with the first roadway, and the response request area may be narrowed as the other vehicle approaches a point where the first roadway and the second roadway merge.

In addition, in order to solve the above-mentioned problems, according to another aspect of the present invention, a program is provided for causing a computer to function as a communication control device mounted on a vehicle, the communication control device comprising: a distance detection unit that detects both a forward inter-vehicle distance , which is the distance between the vehicle and a vehicle in front, and a rear inter-vehicle distance, which is the distance between the vehicle and a vehicle behind; a receiving unit that receives a response request packet from another vehicle traveling on a different road than the vehicle; and a response control unit that determines whether to respond to the response request packet based on whether the distance detected by the distance detection unit is below a threshold, the response control unit determining to respond to the response request packet based on whether both the forward inter-vehicle distance and the rear inter-vehicle distance are below the threshold, and determining not to respond to the response request packet based on whether at least one of the forward inter-vehicle distance or the rear inter-vehicle distance exceeds the threshold .

According to the present invention described above, it is possible to reduce communication traffic for vehicle driving support.

FIG. 2 is an explanatory diagram showing a traveling state of vehicles on merging roads. FIG. 2 is an explanatory diagram showing the configuration of a merging assistance communication device 200 according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing a traveling state of a vehicle 20 at a first point in time. FIG. 11 is an explanatory diagram showing the traveling state of the vehicle 20 at a second point in time. 4 is a flowchart showing the operation of a merging assistance communication device 200 mounted on a main line vehicle. 13 is a flowchart showing a response determination for condition 1. 13 is a flowchart showing a response determination for condition 2. 13 is a flowchart showing a response determination for condition 2 according to a first modified example. 13 is a flowchart showing a response determination for condition 2 according to a second modified example. 2 is an explanatory diagram showing a traveling state of a vehicle 20. FIG. FIG. 13 is an explanatory diagram showing the configuration of a merging assistance communication device 202 according to a fifth modified example.

The following describes in detail an embodiment of the present invention with reference to the accompanying drawings. Note that in this specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals to avoid redundant description.

In addition, in this specification and drawings, multiple components having substantially the same functional configuration may be distinguished by adding different letters after the same reference numeral. For example, multiple components having substantially the same functional configuration or logical meaning may be distinguished as necessary, such as vehicles 20A, 20B, and 20C. However, if there is no need to particularly distinguish between multiple components having substantially the same functional configuration, only the same reference numeral is assigned to each of the multiple components. For example, if there is no need to particularly distinguish between vehicles 20A, 20B, and 20C, each vehicle will be simply referred to as vehicle 20.

1. Overview of the merging support system
An embodiment of the present invention relates to a system for assisting driving of a vehicle, and in particular to a merging assistance system for suppressing vehicle collisions at a merging point where a plurality of roads merge. Hereinafter, an overview of the merging assistance system according to the embodiment of the present invention will be described with reference to FIG.

Figure 1 is an explanatory diagram showing the traveling state of vehicles on roads that merge with each other. In the example shown in Figure 1, a branch road 12, which is a first traveling path, merges with a main road 14, which is a second traveling path. Vehicle 20A is traveling on branch road 12, and vehicles 20B to 20I are traveling on main road 14. Vehicle 20A continues traveling on branch road 12 after the state shown in Figure 1, and merges with vehicle 20 traveling on main road 14 by entering main road 14 at the merging point. Note that in this specification, a vehicle traveling on branch road 12 may be referred to as a merging vehicle, and a vehicle traveling on main road 14 may be referred to as a main road vehicle 2.

Each vehicle 20 according to one embodiment of the present invention is equipped with a merging support communication device 200 as an example of a communication control device. The merging support communication device 200 is capable of transmitting and receiving packets to and from other merging support communication devices 200 mounted on other vehicles 20 via wireless communication such as wide-area wireless communication or vehicle-to-vehicle communication. For ease of explanation, the transmission and reception of packets performed by the merging support communication device 200 may be described in this specification as the transmission and reception of packets by the vehicle 20.

For example, when a merging vehicle approaches a merging point, the merging support communication device 200 mounted on the merging vehicle transmits a response request packet requesting a response from the main line vehicle. The merging support communication device 200 then receives a response packet from the main line vehicle in response to the response request packet, and calculates a plan for merging by acquiring information such as the position and speed of the main line vehicle from the response packet.

Here, the response request packet includes area information indicating the response request area. In the example shown in FIG. 1, the merging assistance communication device 200A transmits a response request packet including area information indicating the response request area P. In this case, the vehicles 20E to 20I located in the response request area P are candidates for transmitting the response packet.

However, in a configuration in which vehicles 20 located in a response request area P transmit response packets, communication traffic increases in proportion to the driving density of vehicles 20. When communication traffic increases, degradation of communication quality and packet loss occur. As a result, the merging assistance communication device 200 may not be able to acquire sufficient response packets, which may make it difficult to properly calculate a merging plan.

The inventors have therefore taken the above circumstances into consideration and have come up with an embodiment of the present invention. According to one embodiment of the present invention, it is possible to suppress an increase in communication traffic due to the transmission of response packets. Below, the configuration and operation of the merging assistance communication device 200 according to one embodiment of the present invention will be described in detail.

2. Configuration of the merging assistance communication device
2 is an explanatory diagram showing a configuration of a merging support communication device 200 according to an embodiment of the present invention. As shown in FIG. 2, the merging support communication device 200 according to an embodiment of the present invention includes a wireless communication unit 210, a vehicle information detection unit 220, a surrounding vehicle information detection unit 230, a request control unit 240, a response control unit 250, and a vehicle control unit 260.

(Wireless Communications Division)
The wireless communication unit 210 is configured to perform inter-vehicle communication with other vehicles 20. The wireless communication unit 210 has a function of performing signal processing for transmitting packets and signal processing for receiving packets. For example, the wireless communication unit 210 of the merging support communication device 200 mounted on the merging vehicle functions as a transmitting unit that broadcasts a response request packet generated by the request control unit 240 and a receiving unit that receives a response packet transmitted from a main line vehicle. When the wireless communication unit 210 receives a response packet, it outputs information included in the response packet to the request control unit 240. In addition, the wireless communication unit 210 of the merging support communication device 200 mounted on the main line vehicle functions as a receiving unit that receives a response request packet transmitted from a merging vehicle and a transmitting unit that transmits the response packet to the merging vehicle. When the wireless communication unit 210 receives a response request packet, it outputs information included in the response request packet to the response control unit 250.

(Vehicle information detection unit)
The host vehicle information detection unit 220 detects information of the vehicle 20 (i.e., the host vehicle) equipped with the merging assistance communication device 200. For example, the host vehicle information detection unit 220 acquires the position, speed, and distance to the merging point of the host vehicle. Such host vehicle information detection unit 220 may include a vehicle speed pulse generator and an inertial sensor (acceleration sensor, gyroscope) that are generally installed in vehicles, map information used in car navigation, or a Global Navigation Satellite System (GNSS).

(Nearby vehicle information detection unit)
The surrounding vehicle information detection unit 230 detects information about other vehicles 20 traveling around the vehicle. For example, the surrounding vehicle information detection unit 230 functions as a distance detection unit that detects the distance between the vehicle and a preceding vehicle traveling in front of the vehicle and the distance between the vehicle and a following vehicle traveling behind the vehicle. The surrounding vehicle information detection unit 230 may have, for example, an autonomous sensor (camera, radar, LIDAR (Light Detection and Ranging), etc.) that may be used to realize driving assistance or automatic driving.

(Request control section)
The request control unit 240 mainly has a function of controlling the transmission of a response request packet based on information obtained from the wireless communication unit 210 and the vehicle information detection unit 220. Specifically, as shown in FIG. 2, the request control unit 240 has the functions of a response request area calculation unit 242, a response request packet generation unit 244, a response packet storage unit 246, and a plan calculation unit 248. These functions of the request control unit 240 can be realized by cooperation between hardware such as a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory) and software. The request control unit 240 mainly operates when the vehicle is a merging vehicle.

When the vehicle, which is a merging vehicle, approaches the merging point, the response request area calculation unit 242 calculates a response request area and outputs area information indicating the response request area to the response request packet generation unit 244. The response request area calculation unit 242 may calculate the response request area, for example, when the distance on the road to the merging point becomes less than a threshold value. The response request area is an area that includes main line vehicles that may arrive at the merging point at the same time as the vehicle, or at a similar time. The response request area calculated by the response request area calculation unit 242 becomes narrower as the vehicle 20, which is a merging vehicle, approaches the merging point. An example of such a calculation of the response request area by the response request area calculation unit 242 will be described below. For simplicity, it is assumed below that the merging vehicle maintains the speed at the time of transmitting the response request packet.

If the speed of the merging vehicle at the current time is v _s and the distance to the merging point is x _join , the expected arrival time to the merging point t _join can be expressed as equation (1).

t _join = x _join / v _s (1)

Next, if the running speed of the main line vehicle is v _main , when there is a main line vehicle that arrives at the merging point at the same time as the merging vehicle, the distance x _main of the main line vehicle from the merging point at the current time can be expressed as formula (2). Note that the running speed v _main of the main line vehicle may be an average value of the speeds indicated by the speed information included in the response packets received from one or more main line vehicles stored in the response packet storage unit 246.

x _main = v _main × t _join (2)

In order to allow a merging vehicle to select an appropriate merging point, the response request area calculation unit 242 assumes that there are errors in the positions and speeds of main line vehicles and calculates a range with arbitrary widths upstream and downstream based on x _main as the response request area. Specifically, the upstream end x _up and downstream end x _down of the response request area are expressed as the following formulas (3) and (4) using the width Δx _main .

x _up = x _main + Δx _main (3)
x _down = x _main - Δx _main (4)

Here, since it is expected that the error in the distance x _main will become smaller as the merging vehicle approaches the merging point, a linear function proportional to t _join , for example, is applied to the width Δx _main as shown in equation (5) so that the response request area becomes narrower as the merging vehicle approaches the merging point.

Δx _main = a × t _join + b (5)

The a and b in equation (5) may be designed taking into account errors in the position and speed of main line vehicles, or may be designed to reflect speed adjustments of merging vehicles, which are not considered in this description.

The response request area calculation unit 242 periodically calculates x _up and x _down by the above-mentioned method from when the merging vehicle approaches the merging point until the merging is completed. Then, the response request area calculation unit 242 converts the calculated x _up and x _down into a format (e.g., latitude and longitude format) that can be recognized by main line vehicles each time, and outputs the area information obtained by the conversion to the response request packet generation unit 244.

Note that when a response request packet including area information is transmitted for the first time, or when there is no main line vehicle and no response packet is returned, information on the main line vehicle is not stored in the response packet storage unit 246, so the response request area calculation unit 242 may use a value designed in advance as the traveling speed v _main of the main line vehicle.

The response request packet generation unit 244 generates a response request packet that stores the area information input from the response request area calculation unit 242, and instructs the wireless communication unit 210 to broadcast the response request packet.

The response packet storage unit 246 stores information contained in a response packet received by the wireless communication unit 210. Since the wireless communication unit 210 can receive response packets multiple times from multiple vehicles 20, the response packet storage unit 246 is configured to store information contained in multiple response packets for each of the multiple vehicles 20. The information contained in the response packet can include the position information of the responding vehicle 20, speed information, the distance to the vehicle ahead, and the distance to the vehicle behind.

The plan calculation unit 248 calculates a driving plan for the host vehicle to merge with a main line vehicle based on the information stored in the response packet storage unit 246 and the information on the host vehicle detected by the host vehicle information detection unit 220. For example, the plan calculation unit 248 identifies an area where it is difficult for the host vehicle to merge based on the distribution of the driving positions of the main line vehicles on the main road 14. The plan calculation unit 248 then calculates the speed of the host vehicle to merge with a main line vehicle within another area, the potential merging area. Below, a specific example of the calculation of a driving plan by the plan calculation unit 248 will be described with reference to Figures 3 and 4, together with a specific example of the calculation of the response request area described above.

Figure 3 is an explanatory diagram showing the running state of vehicle 20 at a first point in time. Figure 4 is an explanatory diagram showing the running state of vehicle 20 at a second point in time that is later than the first point in time.

In the driving state shown in FIG. 3, the merging assistance communication device 200A mounted on the vehicle 20A transmits a response request packet that stores area information indicating the response request area P1. The response request area P1 includes the vehicles 20E to 20I. Among these vehicles 20E to 20I, the vehicles 20E, 20H, and 20I that satisfy the condition 1 or condition 2 described below transmit a response packet.

The plan calculation unit 248 of the merging support communication device 200A identifies the range S1 including the vehicle 20H and the vehicle 20I and the range S3 including the vehicle 20E as ranges where it is difficult for the vehicle to merge from the received response packet. Then, the plan calculation unit 248 calculates the speed of the vehicle 20A to merge with the main line vehicle within the range S2, which is the merging candidate range. That is, the plan calculation unit 248 calculates the speed of the vehicle 20A so that the time when the range S2 reaches the merging point and the time when the vehicle 20A reaches the merging point match, and instructs the vehicle control unit 260 to adjust the speed based on the calculated speed. Note that the speed of any vehicle 20 that transmitted the response packet or the average speed of multiple vehicles 20 may be treated as the moving speed of the range S2. In addition, when there are multiple merging candidate ranges, the plan calculation unit 248 may select one range according to any rule.

After that, as shown in FIG. 4, when vehicle 20A approaches the merging point, merging assistance communication device 200A transmits a response request packet that stores area information indicating response request area P2. Response request area P2 is narrower than response request area P1. Response request area P2 includes vehicle 20E and vehicle 20F. Both vehicle 20E and vehicle 20F satisfy condition 1, which will be described later, and therefore transmit a response packet.

The plan calculation unit 248 of the merging support communication device 200A identifies the surrounding range of vehicle 20E and the surrounding range of vehicle 20F from the received response packet as ranges where it is difficult for the vehicle to merge, and calculates the speed of the vehicle to merge with the main line vehicle within range S4, which is the merging candidate range. That is, the plan calculation unit 248 calculates the speed of vehicle 20A so that the time when range S4 reaches the merging point and the time when vehicle 20A reaches the merging point match, and instructs the vehicle control unit 260 to adjust the speed based on the calculated speed. In this way, the merging support communication device 200 according to one embodiment of the present invention periodically collects information on main line vehicles and adjusts the speed of the vehicle, thereby enabling the vehicle to merge into an open area on the main road 14.

(Response control section)
The response control unit 250 has a function of determining whether or not to respond to a response packet based on information obtained from the wireless communication unit 210, the vehicle information detection unit 220, the surrounding vehicle information detection unit 230, etc. Specifically, as shown in FIG. 2, the response control unit 250 has the functions of a response request packet storage unit 252, a response determination unit 254, and a response packet generation unit 256. These functions of the response control unit 250 can be realized by cooperation between hardware such as a CPU, a ROM, and a RAM, and software. The response control unit 250 mainly operates when the vehicle is a main line vehicle.

The response request packet storage unit 252 stores information contained in a response request packet received by the wireless communication unit 210. Since the wireless communication unit 210 can receive response request packets multiple times from multiple vehicles 20, the response request packet storage unit 252 is configured to store information contained in multiple response request packets for each of the multiple vehicles 20.

When a response request packet is received from a merging vehicle, the response determination unit 254 determines whether or not to respond to the response request packet. When the response determination unit 254 determines that the response request packet is to be responded to, it instructs the response packet generation unit 256 to generate a response packet.

When the response packet generating unit 256 is instructed by the response determining unit 254 to generate a response packet, the response packet generating unit 256 generates a response packet that stores the position information and speed information of the vehicle detected by the vehicle information detecting unit 220, and the distance between the vehicle and the front vehicle and the distance between the vehicle and the rear vehicle detected by the surrounding vehicle information detecting unit 230. The response packet generating unit 256 then instructs the wireless communication unit 210 to transmit the response packet.

Now, the response determination by the response determination unit 254 will be specifically described. As described with reference to Figures 3 and 4, the merging vehicle needs to identify the range in which merging is difficult, and gradually narrow down other candidate merging ranges as it approaches the merging point. From this perspective, when the following condition 1 or condition 2 is met, it is considered that the information of the vehicle itself is the information that is preferentially required by the merging vehicle, and therefore the response determination unit 254 determines to respond to the response request packet when the following condition 1 or condition 2 is met.

Condition 1: There is a possibility that the host vehicle is the leading vehicle or the last vehicle in the response request area.
Condition 2: The distance between the vehicle ahead and the vehicle behind is both equal to or less than a threshold value.

In the traveling state shown in FIG. 3, the response determination unit 254 of the vehicle 20E, which is the leading vehicle in the response request area P1, determines that it will respond to the response request packet because condition 1 is satisfied. The response determination unit 254 of the vehicle 20I, which is the last vehicle in the response request area P1, determines that it will respond to the response request packet because condition 1 is satisfied. The response determination unit 254 of the vehicle H, which is close to both the front vehicle and the rear vehicle, determines that it will respond to the response request packet because condition 2 is satisfied. On the other hand, although the vehicles 20F and 20G are located in the response request area P1, neither condition 1 nor condition 2 is satisfied for the vehicles 20F and 20G, so the response determination unit 254 of the vehicles 20F and 20G determines that it will not respond to the response request packet. As a result, it is possible to suppress an increase in communication traffic due to the transmission of response packets.

After that, in the traveling state shown in FIG. 4, the response determination unit 254 of vehicle 20E, which is the leading vehicle in response request area P2, determines that it will respond to the response request packet because condition 1 is satisfied. Also, the response determination unit 254 of vehicle 20F, which is the last vehicle in response request area P1, determines that it will respond to the response request packet because condition 1 is satisfied.

Thus, in the traveling state shown in FIG. 3, vehicle 20F did not transmit a response packet. However, as shown in FIG. 4, as vehicle 20A approaches the merging point, the response request area narrows, and vehicle 20F becomes the rearmost vehicle in the response request area. Then, vehicle 20F starts transmitting a response packet. In this way, as the merging vehicle approaches the merging point, the proportion of main line vehicles that transmit response packets within the response request area increases based on the above condition 1. As a result, the merging vehicle can narrow the merging candidate range as it approaches the merging point, so it is possible to merge smoothly with the main line vehicle. In addition, even if the proportion of main line vehicles that transmit response packets in the response request area increases, the number of vehicles transmitting response packets is thought to not increase because the number of main line vehicles included in the response request area is decreasing, so it is also possible to avoid an increase in communication traffic.

(Vehicle control unit)
The vehicle control unit 260 is a component for automatically controlling the traveling of the host vehicle. In particular, the vehicle control unit 260 according to an embodiment of the present invention adjusts the speed of the host vehicle according to the traveling plan calculated by the request control unit 240.

3. Operation of the merging assistance communication device
The configuration of the merging assistance communication device 200 according to one embodiment of the present invention has been described above. Next, the operation of the merging assistance communication device 200 according to one embodiment of the present invention will be summarized with reference to Figs.

Figure 5 is a flowchart showing the operation of the merging support communication device 200 mounted on a main line vehicle. As shown in Figure 5, when the wireless communication unit 210 of the merging support communication device 200 receives a response request packet from a merging vehicle (S31), the response determination unit 254 acquires the position information of the host vehicle from the host vehicle information detection unit 220 (S32). Then, the response determination unit 254 determines whether the host vehicle is located within the response request area based on the host vehicle position information and the area information included in the response request packet (S33). If the host vehicle is located outside the response request area (S33/No), the merging support communication device 200 ends the process without sending a response packet.

On the other hand, if the vehicle's position is within the response request area (S33/Yes), the response determination unit 254 obtains the vehicle distance from the vehicle ahead of the vehicle and the vehicle distance from the vehicle behind the vehicle from the surrounding vehicle information detection unit 230 (S34).

Then, the response determination unit 254 determines whether the above-mentioned condition 1 is satisfied (S35). If the condition 1 is satisfied (S36/Yes), the response determination unit 254 instructs the response packet generation unit 256 to generate a response packet, and the wireless communication unit 210 transmits the response packet generated by the response packet generation unit 256 (S37). On the other hand, if the condition 1 is not satisfied (S36/No), the response determination unit 254 determines whether the above-mentioned condition 2 is satisfied (S38). If the condition 2 is satisfied (S39/Yes), the response determination unit 254 instructs the response packet generation unit 256 to generate a response packet, and the wireless communication unit 210 transmits the response packet generated by the response packet generation unit 256 (S37). If the condition 2 is not satisfied (S39/No), the merging assistance communication device 200 ends the process without transmitting the response packet.

(Response determination for condition 1)
Next, the response determination for condition 1 shown in S35 of FIG. 5 will be described in more detail with reference to FIG.

Figure 6 is a flowchart showing the response determination for condition 1. First, the response determination unit 254 determines whether or not a forward vehicle or a rearward vehicle has been detected by the surrounding vehicle information detection unit 230 (S41). If neither a forward vehicle nor a rearward vehicle has been detected (S41/No), the response determination unit 254 determines that condition 1 is satisfied (S45).

When a forward or rear vehicle is detected, the response determination unit 254 determines whether the vehicle is the leading vehicle in the response request area. Specifically, the response determination unit 254 determines whether the detectable range of the forward vehicle extends beyond the downstream end of the response request area and whether the detected vehicle includes the forward vehicle (S42). When the detectable range of the forward vehicle extends beyond the downstream end of the response request area and the detected vehicle is a forward vehicle (S42/Yes), the response determination unit 254 determines that condition 1 is satisfied (S45) based on the fact that the detected vehicle is located outside the response request area (S44/Yes). On the other hand, the response determination unit 254 determines that condition 1 is not satisfied (S46) based on the fact that the detected vehicle is located within the response request area (S44/No).

Next, the response determination unit 254 determines whether the vehicle is the rearmost vehicle in the response request area. Specifically, the response determination unit 254 determines whether the detectable range of the rear vehicle extends outside the upstream end of the response request area and whether the detected vehicle includes the rear vehicle (S43). If the detectable range of the rear vehicle extends outside the upstream end of the response request area and the detected vehicle includes the rear vehicle (S43/Yes), the response determination unit 254 determines that condition 1 is satisfied (S45) based on the fact that the detected vehicle is located outside the response request area (S44/Yes). On the other hand, the response determination unit 254 determines that condition 1 is not satisfied (S46) based on the fact that the detected vehicle is located within the response request area (S44/No).

(Response Determination of Condition 2)
Next, the response determination for condition 2 shown in S38 of FIG. 5 will be described in more detail with reference to FIG.

Figure 7 is a flowchart showing the response determination for condition 2. The response determination unit 254 determines whether the distance between the vehicle and the front vehicle and the distance between the vehicle and the rear vehicle acquired from the surrounding vehicle information detection unit 230 are both equal to or less than a threshold (S61). If the distance between the vehicle and the front vehicle and the distance between the vehicle and the rear vehicle are both equal to or less than a threshold (S61/Yes), the response determination unit 254 determines that condition 2 is satisfied (S62). On the other hand, if at least one of the distance between the vehicle and the front vehicle or the distance between the vehicle and the rear vehicle exceeds the threshold (S61/No), the response determination unit 254 determines that condition 2 is not satisfied (S63).

<4. Effects>
The merging support communication device 200 according to one embodiment of the present invention described above exhibits various operational effects. For example, the merging support communication device 200 according to one embodiment of the present invention transmits a response packet when condition 2 regarding the inter-vehicle distance from the preceding vehicle and the inter-vehicle distance from the following vehicle is satisfied. Therefore, the merging vehicle can receive a response packet that is useful for identifying an area where merging is difficult, and the merging vehicle can appropriately calculate a driving plan for merging while suppressing an increase in communication traffic.

Furthermore, the response packet transmitted by the merging support communication device 200 mounted on the main line vehicle includes the position information of the main line vehicle, speed information, and distance information indicating the distance between the main line vehicle and the vehicle ahead and the distance between the main line vehicle and the vehicle behind. Therefore, the merging support communication device 200 mounted on the merging vehicle can identify a range including the main line vehicle and the vehicle ahead as a range in which merging is difficult, according to the distance between the main line vehicle and the vehicle ahead indicated by the distance information. Note that the response packet does not need to include the speed information of the main line vehicle. In this case, the merging support communication device 200 mounted on the merging vehicle may calculate the speed of the main line vehicle from the change in the position of the main line vehicle indicated by the response packets transmitted at different times.

In addition, the conditions for determining that the merging support communication device 200 installed in the main line vehicle responds to a response request packet include that the vehicle itself is included in a response request area. Therefore, the opportunities for the merging support communication device 200 to transmit a response packet are limited, making it possible to suppress an increase in communication traffic due to the transmission of response packets.

Furthermore, the merging assistance communication device 200 mounted on the main line vehicle determines to respond to the response request packet when there is a possibility that the vehicle is the first or last vehicle in the response request area (when condition 1 is satisfied). Here, the response request area narrows as the merging vehicle approaches the merging point. Therefore, as the merging vehicle approaches the merging point, the proportion of main line vehicles that transmit response packets within the response request area increases, making it possible to narrow the merging candidate range and smoothly merge with the main line vehicle.

5. Modifications
An embodiment of the present invention has been described above. In the following, some modified examples of the above-described embodiment will be described. Note that each modified example described below may be applied alone to the above-described embodiment, or may be applied in combination to the above-described embodiment. Also, each modified example may be applied in place of the configuration described in the above-described embodiment, or may be applied in addition to the configuration described in the above-described embodiment.

(First Modification)
The first modification relates to a modification of the condition 2 for response determination. The condition 2 according to the first modification is as follows.

Condition 2 according to the first variant: The distance between the vehicle and the vehicle ahead or the distance between the vehicle and the vehicle behind is equal to or less than a threshold.

Figure 8 is a flowchart showing the response determination for condition 2 according to the first modified example. The response determination unit 254 determines whether the distance to the front vehicle or the distance to the rear vehicle acquired from the surrounding vehicle information detection unit 230 is equal to or less than a threshold (S71). If at least one of the distance to the front vehicle or the distance to the rear vehicle is equal to or less than the threshold (S71/Yes), it is determined that condition 2 is met (S72). On the other hand, if both the distance to the front vehicle or the distance to the rear vehicle exceed the threshold (S71/No), the response determination unit 254 determines that condition 2 is not met (S73).

According to this configuration, main line vehicles that are only close to the vehicle ahead or the vehicle behind also transmit a response packet. For example, in the traveling state shown in FIG. 3, vehicle 20G, which is a main line vehicle, also transmits a response packet. According to this first modified example, the merging assistance communication device 200 mounted on the merging vehicle can more accurately grasp the area where merging is difficult from an early stage.

In addition, in this modification 1, the surrounding vehicle information detection unit 230 may detect only one of the following distances, the distance to the vehicle ahead and the distance to the vehicle behind, and the response determination unit 254 may determine whether or not condition 2 is satisfied based on whether or not the following distance is equal to or less than a threshold value.

(Second Modification)
The second modification also relates to a modification of the condition 2 for response determination. The condition 2 according to the second modification is as follows.

Condition 2 according to the second variant: The distance between the vehicle and the vehicle ahead and the vehicle and the vehicle and the vehicle behind both exceed a threshold value.

Figure 9 is a flowchart showing the response determination for condition 2 according to the second modified example. The response determination unit 254 determines whether the vehicle distance from the front vehicle and the vehicle distance from the rear vehicle acquired from the surrounding vehicle information detection unit 230 both exceed a threshold value (S81). If the vehicle distance from the front vehicle and the vehicle distance from the rear vehicle both exceed the threshold value (S81/Yes), the response determination unit 254 determines that condition 2 is satisfied (S82). On the other hand, if at least one of the vehicle distance from the front vehicle or the vehicle distance from the rear vehicle is equal to or less than the threshold value (S81/No), the response determination unit 254 determines that condition 2 is not satisfied (S83).

In the second modified example, the response packet is sent not by a main line vehicle with which merging is difficult in the area around the vehicle, but by a main line vehicle with which merging is possible in the area around the vehicle. Therefore, the merging support communication device 200 mounted on the merging vehicle can directly identify the candidate merging area based on the response packet received from the main line vehicle.

For example, in the driving state shown in FIG. 10, vehicle 20F, which is a main line vehicle, satisfies condition 2, and thus vehicle 20F transmits a response packet. In this case, the merging support communication device 200A mounted on vehicle 20A, which is a merging vehicle, can directly identify the range S5 behind vehicle 20F and the range S6 in front of vehicle 20F as potential merging ranges.

(Third Modification)
In the above, an example has been described in which the response request packet includes area information including a response request area. In the third modified example, the response request packet does not include area information. Even if the response request packet does not include area information, the response request packet is transmitted wirelessly, so that the area in which the response request packet can be received is limited. As a result, it is possible to limit main line vehicles that are candidates for transmitting a response packet.

(Fourth Modification)
In the above, an example in which the embodiment of the present invention is applied to merging support on roads where two vehicles merge into each other has been described. However, the application of the embodiment of the present invention is not limited to this. For example, the embodiment of the present invention can also be applied to lane change support. In this case, a first vehicle traveling on a first lane (first travel path) transmits a response request packet when it is about to move to a second lane (second travel path), and another vehicle that satisfies condition 2 for traveling on the second lane transmits a response packet, thereby enabling the first vehicle to move smoothly to the second lane. Note that, when a lane change point is determined, it is also possible to calculate a response request area so that the response request area becomes narrower as the first vehicle approaches the lane change point, as in the above-mentioned embodiment.

(Fifth Modification)
In the above, an example in which the merging vehicle runs by automatic driving has been described, but in the fifth modified example, the merging vehicle runs by the driver's operation. Hereinafter, the configuration of the merging assistance communication device 202 according to the fifth modified example will be described with reference to FIG. 11 .

Figure 11 is an explanatory diagram showing the configuration of a merging support communication device 202 according to the fifth modified example. As shown in Figure 11, the merging support communication device 202 according to the fifth modified example includes a wireless communication unit 210, a vehicle information detection unit 220, a surrounding vehicle information detection unit 230, a request control unit 240, a response control unit 250, and a user I/F unit 270. The functions of the wireless communication unit 210, the vehicle information detection unit 220, the surrounding vehicle information detection unit 230, the request control unit 240, and the response control unit 250 are as described with reference to Figure 2, so detailed description here will be omitted.

The user I/F unit 270 is an interface for conveying information to the driver of the vehicle 20. For example, the user I/F unit 270 may be a display that outputs an indication or a speaker that outputs an audio. The user I/F unit 270 conveys the driving plan, i.e., speed adjustment information up to the junction, to the driver by outputting an indication or audio indicating the driving plan calculated by the plan calculation unit 248.

With this configuration, the driver can operate the vehicle according to the driving plan transmitted by the user I/F unit 270, which makes it possible to achieve a smooth merge while suppressing an increase in communication traffic, as in the above-described embodiment.

＜6. Supplementary Information＞
Although the preferred embodiment of the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to such an example. It is clear that a person having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or altered examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

For example, each step in the processing of the merging assistance communication device 200 does not necessarily have to be processed in chronological order according to the order described in the flowchart. For example, each step in the processing of the merging assistance communication device 200 may be processed in an order different from the order described in the flowchart, or may be processed in parallel.

It is also possible to create a computer program for causing the hardware, such as the CPU, ROM, and RAM, built into the merging support communication device 200 to perform functions equivalent to those of each of the components of the merging support communication device 200 described above. A storage medium on which the computer program is stored is also provided.

20 Vehicle 200, 202 Merge support communication device 210 Wireless communication unit 220 Vehicle information detection unit 230 Surrounding vehicle information detection unit 240 Request control unit 242 Response request area calculation unit 244 Response request packet generation unit 246 Response packet storage unit 248 Plan calculation unit 250 Response control unit 252 Response request packet storage unit 254 Response determination unit 256 Response packet generation unit 260 Vehicle control unit 270 User I/F unit

Claims (9)

A communication control device mounted on a vehicle,
a distance detection unit that detects both a forward inter-vehicle distance between the vehicle and a vehicle ahead and a rear inter-vehicle distance between the vehicle and a vehicle behind the vehicle;
a receiving unit for receiving a response request packet from another vehicle traveling on a different road from that of the vehicle;
a response control unit that determines whether or not to respond to the response request packet based on whether or not the distance detected by the distance detection unit is equal to or less than a threshold;
Equipped with
The response control unit:
determining to respond to the response request packet based on the fact that both the front inter-vehicle distance and the rear inter-vehicle distance are equal to or less than the threshold;
The communication control device determines not to respond to the response request packet based on at least one of the forward inter-vehicle distance or the rear inter-vehicle distance exceeding the threshold value. A communication control device mounted on a vehicle,
a distance detection unit that detects a distance between the vehicle and a preceding vehicle or a distance between the vehicle and a following vehicle;
a receiving unit that receives a response request packet including area information indicating a response request area from another vehicle traveling on a different road from the vehicle;
a response control unit that determines whether or not to respond to the response request packet;
Equipped with
the response control unit determines to respond to the response request packet when the vehicle corresponds to the rearmost vehicle in the response request area and when the vehicle corresponds to the leading vehicle in the response request area;
A communication control device that determines whether or not to respond to the response request packet based on whether the distance detected by the distance detection unit is below a threshold value when the vehicle is neither the first vehicle nor the last vehicle in the response request area. The communication control device according to claim 1 , wherein the response control unit generates a response packet including position information of the vehicle when it is determined to respond to the response request packet. The communication control device according to claim 3, wherein the response packet further includes speed information of the vehicle and distance information indicating the distance detected by the distance detection unit. the distance detection unit detects both a forward inter-vehicle distance, which is a distance between the vehicle and the preceding vehicle, and a rear inter-vehicle distance, which is a distance between the vehicle and the following vehicle;
The response control unit:
determining to respond to the response request packet based on the fact that both the front inter-vehicle distance and the rear inter-vehicle distance are equal to or less than the threshold;
The communication control device according to claim 2 , wherein the control device determines not to respond to the response request packet based on at least one of the forward inter-vehicle distance or the rear inter-vehicle distance exceeding the threshold value. the response request packet includes area information indicating a response request area,
The communication control device according to claim 1 , wherein a condition for the response control unit to determine that the response to the response request packet is that the vehicle is included in the response request area. The communication control device according to claim 6, wherein the response control unit determines to respond to the response request packet when there is a possibility that the vehicle corresponds to the leading vehicle or the last vehicle in the response request area, regardless of whether the distance detected by the distance detection unit is equal to or less than a threshold value. the vehicle is traveling on a first travel path, and the other vehicle is traveling on a second travel path that merges with the first travel path;
The communication control device according to claim 2 , wherein the response request area becomes narrower as the other vehicle approaches a junction between the first travel path and the second travel path. Computer,
A communication control device mounted on a vehicle,
a distance detection unit that detects both a forward inter-vehicle distance between the vehicle and a vehicle ahead and a rear inter-vehicle distance between the vehicle and a vehicle behind the vehicle;
a receiving unit for receiving a response request packet from another vehicle traveling on a different road from that of the vehicle;
a response control unit that determines whether to respond to the response request packet based on whether the distance detected by the distance detection unit is equal to or less than a threshold;
Equipped with
The response control unit:
determining to respond to the response request packet based on the fact that both the front inter-vehicle distance and the rear inter-vehicle distance are equal to or less than the threshold;
A program for causing the device to function as a communication control device that determines not to respond to the response request packet based on at least one of the forward vehicle distance or the rear vehicle distance exceeding the threshold value.

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