JP2014059823A - Information sharing system, information sharing method and on-vehicle terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information sharing system allowing vehicles to share information useful for drivers by inter-vehicle communication, and to provide an information sharing method.SOLUTION: A roadside device transmits facility information corresponding to the roadside device to an on-vehicle terminal held by a vehicle passing through a predetermined point. Also, the vehicle receives the facility information from the roadside device and another vehicle and stores the received facility information. The vehicle includes: facility information transmission means for extracting the stored facility information and transmitting the information to another vehicle; facility information request transmission means for transmitting information for requesting transmission of the facility information to another vehicle; and facility information request receiving means for receiving the facility information request from another vehicle. When the facility information request is not received from another vehicle, the facility information transmission means extracts the facility information by a predetermined algorithm and periodically transmits the information. When receiving the facility information request from another vehicle, the facility information transmission means extracts and transmits the facility information on the basis of the information included in the facility information request.

Description

  The present invention relates to a technique for sharing information among a plurality of vehicles.

  2. Description of the Related Art A technique for providing information on various facilities scattered throughout a city to a vehicle is known. Examples of information on facilities (hereinafter referred to as facility information) include information on gas stations and parking lots. By providing the vehicle with information such as gasoline prices, parking space availability, and parking fees, drivers can search for facilities that meet their needs.

  For example, Patent Document 1 describes a parking lot information providing system for guiding a parking lot to a driver. In this system, the information providing server manages the parking lot availability information, and when there is a request from the vehicle, it generates available parking lot candidates and assigns priorities in the order in which the vehicle is easily accessible. providing. Although the system described in Patent Document 1 distributes only parking lot information, facility information other than parking lots may be distributed.

  However, since the system described in Patent Document 1 collects all facility information in a server and the server processes requests transmitted from vehicles, the amount of processing and communication increases as the number of vehicles and facilities increases. There is a problem that the response gets worse. In addition, the user must bear a communication fee.

  To solve this problem, an ad hoc network can be used. For example, in the information distribution system described in Patent Document 2, each time a vehicle uses a store, the store acquires information about the store through road-to-vehicle communication. Then, the acquired store information is transmitted to other vehicles that wish to acquire the store information using inter-vehicle communication. According to the information distribution system, vehicles can share facility information without imposing a burden on the network and the server.

JP 2012-058931 A JP 2007-240821 A

  When the system described in Patent Document 2 is used, facilities information can be shared between vehicles by inter-vehicle communication. However, in this system, since a vehicle having information transmits information to a vehicle for which acquisition of the information is desired, information cannot be diffused to many vehicles. Unlike information on restaurants that depend on user preferences, information on facilities closely related to vehicle operation, such as parking lots, charging facilities for electric vehicles, and information on gas stations, is shared by as many vehicles as possible. However, the invention described in Patent Document 2 cannot achieve this.

  As a method for spreading information to many vehicles by inter-vehicle communication, there is a method in which each vehicle repeatedly transmits received information. However, if broadcasting is repeated without limitation without selecting information to be transmitted, a problem arises that the transmission path is congested. In order to solve these problems, it is necessary for the vehicle to select and share only facility information useful to the driver.

  The present invention has been made in consideration of the above-described problems, and an object thereof is to provide an information sharing system and an information sharing method capable of sharing information useful for a driver through inter-vehicle communication.

The information sharing system according to the present invention is a system including a roadside device and a plurality of vehicles.
Specifically, the roadside device has facility information distribution means for transmitting facility information, which is information on a facility corresponding to the roadside device, to a vehicle passing through a predetermined point.
The vehicle also includes a first facility information receiving unit that receives the facility information from the roadside device, a second facility information receiving unit that receives the facility information from another vehicle, and the first and second Facility information storing means for storing facility information received by the facility information receiving means, facility information transmitting means for extracting facility information from the facility information storing means and transmitting it to other vehicles, and information for requesting transmission of facility information And it has the facility information request | requirement transmission means which transmits the facility information request | requirement containing the information regarding the own vehicle to another vehicle, and the facility information request | requirement reception means which receives the said facility information request | requirement from another vehicle.
In addition, the facility information transmitting means, when not receiving the facility information request from another vehicle, extracts the facility information by a predetermined algorithm and periodically transmits it, and receives the facility information request from the other vehicle. In this case, the facility information is extracted based on the information included in the facility information request and transmitted.

  The roadside device in the present invention is arranged at a predetermined position on the road and transmits facility information, which is information on a corresponding facility, to a passing vehicle. The facility is an arbitrary facility that can be entered from the road, such as a parking lot, a gas station, and a charging facility for an electric vehicle. The facility information is information regarding the facility, such as a parking fee, a gasoline price, a charging fee, and full / vacant information. The transmitted facility information is received and stored by the vehicle.

In addition, the vehicle can transmit a facility information request to another vehicle. The facility information request is information that requests another vehicle to transmit facility information that the vehicle has. The facility information request includes information about the host vehicle such as the current position, the traveling direction, and the cruising distance, and the vehicle that has received the facility information request refers to the information to the vehicle that transmitted the request. Appropriate facility information can be extracted and transmitted.
The facility information request can be transmitted at an arbitrary timing. For example, it may be transmitted by the operation of the driver, or may be automatically transmitted when the cruising distance becomes short.

When the vehicle has not received the facility information request, the vehicle periodically extracts and transmits the stored facility information using a predetermined algorithm. The predetermined algorithm may be any algorithm as long as it can extract facility information useful for surrounding vehicles. For example, “extract facility information within a predetermined range centering on the current position”. Thereby, when there is no vehicle that wants information, it is possible to share facility information between neighboring vehicles.
In addition, when a facility information request is received from another vehicle, the facility information that matches the request is extracted from the stored facility information and transmitted. Thus, when a vehicle that wants information appears, surrounding vehicles can extract and transmit information desired by the vehicle from information shared in advance.

The facility information transmitting means may transmit the extracted facility information without waiting for the arrival of a cycle when a facility information request is received from another vehicle. When a facility information request is received from another vehicle, the facility information is transmitted without waiting for the arrival of the cycle, so that the vehicle that wants the information can obtain the desired facility information in a short time.

  The facility information request transmitted by the facility information requesting unit includes position information of the host vehicle, and the facility information transmitting unit receives the facility information transmitted when the facility information request is received. An extraction may be performed based on the position information included in the information request.

  The facility information request preferably includes at least position information of the host vehicle. Since the vehicle that provides the information extracts the facility information based on the position information, the vehicle that requested the facility information can acquire information on the facility in the vicinity of the place where the vehicle is traveling.

  In addition, when the facility information transmission unit receives the facility information request from another vehicle, the facility information transmission unit calculates a time during which communication is possible from the distance and relative speed with the other vehicle, and communication is performed at the time. A feature amount of facility information may be extracted and transmitted.

  When traveling vehicles communicate with each other, the time during which the vehicles are within the communicable range is limited. Therefore, by acquiring the distance and speed with the other vehicle and calculating the time for which communication is possible, the amount of information that can be transmitted can be determined, and communication is not interrupted while information is being transmitted. Can do.

  In addition, when the facility information transmitting means extracts and transmits the facility information, if a plurality of facility information is stored in the facility information storage means, the facility information transmitting means is more than the facility information received from other vehicles. The facility information with a small number of receptions may be given priority, or the facility information with a small number of transmissions may be given priority over the facility information with a large number of transmissions to other vehicles.

  When the own vehicle has a plurality of facility information, it is preferable to transmit information that is not shared more preferentially than information shared by many vehicles. To what extent the facility information is shared by other vehicles can be estimated by the number of times the facility information is transmitted and received. Distribute information that is not shared by many vehicles to more vehicles by preferentially sending information that is received less frequently from other vehicles or sent to other vehicles. be able to.

The vehicle may be an electric vehicle, and the facility corresponding to the roadside device may be a charging facility for the electric vehicle.
Information related to the charging facility (hereinafter referred to as charging facility information) includes a location of the charging facility, a charging fee, a charging standard, availability information, and the like. Sharing charging facility information between electric vehicles eliminates the need for the driver to search for a charging facility each time the amount of stored electricity decreases, greatly improving convenience.

  The facility information request transmitted by the facility information request unit further includes a travelable distance of the host vehicle, and the facility information transmission unit further uses the travelable distance included in the received facility information request, The facility information to be transmitted may be extracted.

  When the target is an electric vehicle, by including the cruising distance calculated from the amount of stored electricity (remaining battery amount) in the facility information request, it is possible to acquire only information on charging facilities within the reachable range.

Further, the facility information request transmitting means may transmit the facility information request to another vehicle when the storage amount of the own vehicle falls below a threshold value. When the amount of electricity stored in the electric vehicle decreases, the facility information request is automatically transmitted, so that the driver can obtain the charging facility information without performing any troublesome operations.

In addition, the facility information request transmission means periodically transmits the facility information request to another vehicle when the storage amount of the own vehicle falls below a threshold value, and is less than when the storage amount is large. In addition, the facility information request may be transmitted in a shorter cycle.
As described above, the facility information request may be transmitted in a shorter cycle as the storage amount decreases. By doing in this way, the vehicle which has the charging equipment information suitable for conditions can be discovered earlier.

  ADVANTAGE OF THE INVENTION According to this invention, the information sharing system and the information sharing method which can share information useful for a driver by vehicle-to-vehicle communication can be provided.

It is a figure explaining the arrangement position of a roadside device. It is a figure explaining the format of the charging equipment information in 1st embodiment. It is a system configuration figure of a roadside device in a first embodiment. It is a system configuration figure of an in-vehicle terminal in a first embodiment. It is a flowchart of the process which transmits charging equipment information from a roadside apparatus to a vehicle-mounted terminal. It is a flowchart of the process which transmits charging equipment information which an in-vehicle terminal performs. It is a figure explaining the structure of the transmission message in 1st embodiment. It is a figure explaining the format of the vehicle information in 1st embodiment. It is a processing flowchart at the time of receiving charging equipment information which an in-vehicle terminal performs. It is a figure explaining the extraction method of the charging equipment information in 1st embodiment. It is a figure explaining the relationship between the electrical storage amount and waiting time based on the modification of 1st embodiment. It is an example of the charging equipment information based on 3rd embodiment. It is an example of facility information other than charging equipment according to a modification.

(First embodiment)
The information sharing system according to the first embodiment includes a roadside device 10 provided in a charging stand (hereinafter referred to as a charging facility) of an electric vehicle and an in-vehicle terminal 20 mounted on the vehicle, and charging facility information is transferred between vehicles. Shared system.

<How to share charging equipment information>
Before describing the roadside device and the in-vehicle terminal, an outline of a method for sharing charging facility information between road vehicles and between vehicles will be described. FIG. 1 is a diagram illustrating a place where a roadside device is installed. The roadside device is a wireless device provided in the charging facility, and stores charging facility information as shown in FIG. Further, the roadside device transmits the charging facility information to the vehicle that passes in the vicinity of the charging facility by wireless communication. The in-vehicle terminal mounted on the vehicle receives and stores the charging facility information transmitted from the roadside device.

On the other hand, the in-vehicle terminal periodically broadcasts the stored charging facility information to other in-vehicle terminals. When the in-vehicle terminal stores a plurality of charging facility information, the amount of information that can be transmitted at a time is limited, and thus information is extracted and transmitted by a predetermined algorithm. A specific algorithm for extracting charging facility information will be described later. The charging facility information transmitted by the in-vehicle terminal is received and stored by another in-vehicle terminal. By repeating this, the charging facility information transmitted from the roadside device can be shared among a plurality of in-vehicle terminals.

Moreover, the vehicle-mounted terminal can request | require transmission of charging equipment information with respect to another vehicle-mounted terminal. The information transmitted at this time is a facility information request in the present invention. In this embodiment, this is called a charging facility information request.
For example, when the amount of electricity stored in the host vehicle is decreasing and the host vehicle does not have charging facility information, or has charging facility information but the driver does not desire, The charging equipment information request is transmitted to the in-vehicle terminal. The charging facility information request includes information for another on-vehicle terminal to extract charging facility information. For example, the current position of the host vehicle, the remaining distance that can be traveled, and the price range of the desired charging fee. Other in-vehicle terminals refer to the information and extract charging facility information to be transmitted.

When the in-vehicle terminal has not received the charging facility information request, the in-vehicle terminal extracts information to be transmitted from the stored charging facility information by a predetermined algorithm and periodically transmits the information. If a charging facility information request is received, charging facility information that meets the conditions is extracted based on the content of the request, and transmitted regardless of the period.
Through the operation described above, each in-vehicle terminal can efficiently share the charging facility information transmitted from the roadside device and can quickly transmit it to the vehicle that wants the information.

<System configuration>
Details of the embodiment for realizing the operation described above will be described.
The roadside device 10 is a wireless device that is installed near the charging facility and transmits charging facility information related to the charging facility to the in-vehicle terminal 20. The in-vehicle terminal 20 is a terminal that provides charging facility information to a driver. The in-vehicle terminal 20 has a function of exchanging information with other in-vehicle terminals by wireless communication.

First, the roadside device 10 will be described. FIG. 3 is a system configuration diagram of the roadside apparatus 10 according to the first embodiment.
The facility information storage unit 11 is configured by a non-volatile memory or a fixed disk device, and is a means for storing charging facility information that is information related to the charging facility associated with the roadside device. As shown in FIG. 2, the charging facility information is information including the time when the information is issued, the location information of the charging facility, the availability status, the usage fee, the usage conditions, and the like.
The communication unit 12 is means for performing wireless communication with the in-vehicle terminal 20. As long as the charging facility information can be transmitted by wireless communication, the frequency to be used and the communication method are not particularly limited.

Next, the in-vehicle terminal 20 will be described. FIG. 4 is a system configuration diagram of the in-vehicle terminal 20.
The facility information storage unit 21 is means for storing charging facility information received from a roadside device or other vehicle-mounted terminal. Similar to the facility information storage unit 11, a non-volatile memory or a fixed disk device may be used. The facility information storage unit 21 can store a plurality of charging facility information.
The control unit 22 is means for controlling the entire in-vehicle terminal 20. Specifically, it performs management of the transmission cycle of charging facility information, reading of charging facility information requests received from other in-vehicle terminals, generation of charging facility information requests, and the like.

The transmission information generation unit 23 is a unit that extracts information to be transmitted to other in-vehicle terminals from the facility information storage unit 21 and generates a message to be transmitted. The amount of information that the in-vehicle terminal can transmit at a time is limited, and when a charging facility information request is received, charging facility information that meets the conditions must be transmitted. Therefore, the transmission information generating unit 23 extracts information to be transmitted from the stored charging facility information by a predetermined algorithm.
The communication unit 24 is a unit that communicates with a roadside device or another in-vehicle terminal wirelessly. The communication unit 24 performs wireless communication in the same manner as the communication unit 12.

<Transmission of charging facility information by roadside device>
Next, processing for transmitting charging facility information from the roadside device to the in-vehicle terminal will be described. FIG. 5 is a flowchart of charging facility information transmission processing performed by the roadside device and the in-vehicle terminal.
The communication unit 12 included in the roadside device periodically transmits a radio signal toward a point on the road. When the communication unit 24 of the in-vehicle terminal receives the wireless signal and the negotiation is established, the flowchart shown in FIG. 5 is started.

In step S <b> 11, the roadside device transmits the charging facility information stored in the facility information storage unit 11 to the in-vehicle terminal via the communication unit 12. In step S <b> 12, the in-vehicle terminal stores the charging facility information received through the communication unit 24 in the charging facility information storage unit 21. If there is charging facility information that is already stored, additional storage is performed. However, if the capacity that can be stored is exceeded, the storage capacity may be secured by an arbitrary deletion process. For example, the charging facility information with the oldest reception time may be deleted, or the charging facility information with the longest distance from the current position may be deleted.
By the above process, the vehicle-mounted terminal mounted on the vehicle can receive and store the charging facility information corresponding to the roadside device every time it passes through the vicinity of the roadside device.

<Periodic transmission of charging equipment information by in-vehicle terminal>
Next, a process in which the in-vehicle terminal 20 periodically transmits charging facility information to other in-vehicle terminals will be described. FIG. 6 is a flowchart of periodic transmission processing of charging facility information performed by the in-vehicle terminal 20.
The process shown in FIG. 6 is always executed while the vehicle is operating. For example, it may start when the engine starts and end when the engine stops.

  First, in step S21, the control unit 22 confirms whether the amount of power stored in the host vehicle is less than a threshold value. The threshold value for the amount of stored electricity is the amount of stored electricity to start searching for charging equipment. The said threshold value should just be an electrical storage amount which can drive | work to the nearby charging equipment. Here, when the charged amount is less than the threshold value, the process proceeds to step S22, the search flag indicating that the charging facility is being searched is turned ON, and then the process proceeds to step S23. When the charged amount is equal to or greater than the threshold value, the process proceeds to step S23 as it is. The search flag will be described in step S24.

  Next, in step S23, the control unit 22 confirms whether the timing for transmitting the charging facility information has arrived. Specifically, the elapsed time from the time when the charging facility information was transmitted (step S25) in the previous process is confirmed, and if the predetermined time has passed, the process proceeds to step S24, and if not, the process returns to step S21. . The predetermined time may be set in any way as desired.

In step S24, the transmission information generation unit 23 extracts charging facility information to be transmitted to other in-vehicle terminals from the facility information storage unit 21, and generates data to be transmitted (hereinafter referred to as a transmission message). This process will be described in detail.
FIG. 7 shows the structure of a transmission message transmitted and received between in-vehicle terminals. The transmission message includes information related to the traveling state of the host vehicle (hereinafter referred to as vehicle information) and a plurality of charging facility information extracted from the facility information storage unit.

An example of vehicle information is shown in FIG. The vehicle information is data representing the traveling state of the host vehicle, and is data including the current position, speed, traveling direction, and the like. Further, the vehicle information has a search flag indicating that the charging facility is being searched. The search flag included in the vehicle information is normally 0 (see FIG. 8A), but becomes 1 when the process for turning on the search flag is executed in step S22 (see FIG. 8B). When the search flag is 1, a value is assigned to the field representing the desired condition. Here, it is indicated as a condition that the charging fee is “100 yen or less for 30 minutes” and the charging standard is “CHAdeMO (registered trademark)”. The desired condition may be input by the user when turning on the search flag, or a condition stored in advance may be used.

  Next, processing for extracting charging facility information will be described. In step S24, charging facility information is extracted by a predetermined algorithm. For example, a predetermined number of pieces of information may be selected in ascending order from the current position of the host vehicle, or by referring to the “information issue time” field of the stored charging facility information, The number may be selected. In this way, charging facility information useful for surrounding vehicles can be extracted. Further, a predetermined number may be randomly selected from the stored charging facility information. In addition, an upper limit of the number of transmissions may be provided for each charging facility information, and information that has reached the upper limit of the number of transmissions may not be transmitted. Thus, an arbitrary method can be used for the method of extracting charging facility information performed in step S24.

When the extraction process of the charging facility information is completed, the transmission information generation unit 23 generates a transmission message from the vehicle information and the plurality of extracted charging facility information. If no charging facility information is stored or if there is no extracted result, the processing in steps S24 and S25 may be skipped. If there is no information to be transmitted but the search flag is ON, a transmission message including only vehicle information may be generated. A transmission message whose search flag is 1 included in the vehicle information is a facility information request in the present invention.
In step S25, the communication unit 24 broadcasts the generated transmission message. After transmission, the process returns to step S21.

<Receiving charging facility information by in-vehicle terminal>
Next, processing when the in-vehicle terminal receives a transmission message transmitted by another in-vehicle terminal will be described. FIG. 9 is a process flowchart when the in-vehicle terminal 20 receives a transmission message transmitted by another in-vehicle terminal.

When the in-vehicle terminal 20 receives a transmission message broadcast by another in-vehicle terminal, the process shown in FIG. 9 is started.
First, in step S31, the facility information storage unit 21 stores the charging facility information included in the received transmission message. At this time, when the same information is already stored, the information may be discarded or overwritten. Further, whether to discard or store the information may be selected depending on the content of the charging facility information. For example, when the current position information can be acquired, the information about the charging facility that is more than a predetermined distance from the current position may be discarded, or the information about the charging facility that is opposite to the traveling direction of the host vehicle is discarded. May be. Moreover, when the storage capacity of the facility information storage unit is insufficient, a priority may be given to the charging facility information, and the storage capacity may be secured by deleting in order from the information with the lowest priority.

  In step S32, the control unit 22 refers to the vehicle information included in the received transmission message and confirms the search flag. Here, when the search flag is 1, it means that the in-vehicle terminal that has transmitted the transmission message is requesting the charging facility information. Therefore, the processing is shifted to step S33 and the charging facility information is transmitted. Move on. If the search flag is 0, the process is terminated.

In step S33, the transmission information generation unit 23 uses a plurality of stored charging facility information,
Charging facility information suitable for a vehicle (hereinafter referred to as a partner vehicle) on which the in-vehicle terminal that has transmitted the transmission message is mounted is extracted. Specifically, the charging facility information is extracted from the facility information storage unit based on the vehicle information included in the received transmission message.
Here, three patterns are exemplified for an algorithm for extracting charging facility information based on vehicle information.

(1) Information is extracted based on the position information of the opponent vehicle and the travelable distance. By obtaining the current position of the opponent vehicle and the travelable distance from the vehicle information, the information is present in an area where the partner vehicle can reach. The charging equipment to be extracted can be extracted. For example, as shown in FIG. 10 (a), charging facilities in a circle having a radius that is a travelable distance centered on the current position of the opponent vehicle can be extracted and set as transmission targets.
(2) Extracting information based on the position information and the traveling direction of the partner vehicle By acquiring the current position and the traveling direction of the partner vehicle, it is possible to extract a charging facility that is close to the travel route of the partner vehicle. For example, as shown in FIG. 10B, a charging facility within the traveling direction ± predetermined angle of the opponent vehicle can be extracted and set as a transmission target.
(3) Extracting information based on the position information and destination of the opponent vehicle By acquiring the current position of the opponent vehicle and the destination, it is possible to extract a charging facility located near the route to the destination it can. For example, as shown in FIG. 10C, charging facilities within a predetermined distance from a line connecting the current position of the opponent vehicle and the destination can be extracted and set as transmission targets.

Here, three types of extraction methods are exemplified, but any extraction method may be used as long as charging facility information can be extracted based on vehicle information included in the received transmission message. For example, after performing the extraction by the above method, charging facilities that match the desired conditions (charges and charging standards) included in the vehicle information may be further narrowed down, and only the desired conditions are considered without considering the location of the charging facilities. May be used for extraction. Moreover, you may extract based only on the present position of the own vehicle, without considering the vehicle information acquired from the other party vehicle.
In addition to this, as shown in FIG. 8C, the vehicle information includes information for identifying the charging facility information stored in the in-vehicle terminal, and is extracted by excluding the charging facility information in step S33. It may be.

Return to the description of the flowchart. When the extraction of the charging facility information is completed, the transmission information generating unit 23 adds the vehicle information of the own vehicle to the extracted charging facility information and generates a transmission message. The format of the generated transmission message is the same as that in FIG.
The generated transmission message is transmitted by the communication unit 24 in step S34.

  In the first embodiment, the roadside device and the vehicle-mounted terminal transmit and receive charging facility information through the processing described above. Since an ad hoc network is used for transmitting and receiving information, there is an advantage that the server is not burdened even if the number of users increases. Also, vehicles traveling in the vicinity can share charging facility information, and appropriate charging facility information can be transmitted to the vehicle for which information is requested.

Note that the charging facility information shown in FIG. 2 and the vehicle information shown in FIG. 8 are merely examples, and any information may be included as long as the information can be processed by the in-vehicle terminal. Further, the transmission cycle of the transmission message does not need to be a constant interval as long as transmission can be performed periodically, and the interval may be determined in any way.
In step S21, the search flag is set to ON when the amount of stored power is less than the threshold, but the search flag may be switched manually. Further, the search flag may be turned OFF when the vehicle is charged and the storage amount is recovered, or the search flag may be turned OFF by a user operation.
In the first embodiment, when transmitting a transmission message, transmission is performed after the arrival of the transmission timing in step S23. However, if the condition that the search flag is ON is satisfied, only vehicle information is transmitted. It is also possible to immediately transmit a transmission message including the message.

(Modification of the first embodiment)
In the first embodiment, the transmission process shown in FIG. 6 is performed at a constant cycle. On the other hand, this modification is embodiment which changes a transmission period according to the electrical storage amount of a vehicle.
Specifically, the waiting time in step S23 is shortened as the charged amount decreases. In other words, the transmission message is transmitted at a shorter cycle as the amount of power storage becomes shorter.

FIG. 11 is a graph showing the relationship between the waiting time used in step S23 and the SOC (State Of Charge: the ratio of the remaining charge with respect to the full charge) representing the charged amount. In this example, SOC
When the value is less than 15, the transmission interval is controlled to be shorter than the predetermined time. In the present modification, the transmission cycle of the transmission message is shortened as the amount of stored electricity decreases, so it can be expected to collect more charging facility information.

  In addition, you may change the content of the desired conditions contained in vehicle information with a transmission period. For example, the charge amount is normally set to “100 yen or less for 30 minutes”, but when the amount of stored electricity is reduced, “200 yen or less for 30 minutes” is set. The conditions may be relaxed accordingly.

(Second embodiment)
In the first embodiment, in step S33, all charging facility information that meets the conditions is extracted and transmitted. However, since the vehicle is constantly moving, communication may be interrupted during transmission. There is. In the second embodiment, in order to prevent this, the communicable time is calculated from the mutual speed and distance, and the amount of information to be transmitted is determined.

A difference between the in-vehicle terminal 20 according to the second embodiment and the first embodiment will be described.
The control unit 22 has a function of calculating a communicable time from the received vehicle information and information acquired from the host vehicle. Further, the transmission information generation unit 23 has a function of extracting the amount of information that can be transmitted in the calculated communicable time when extracting the charging facility information. Other configurations are the same as those of the first embodiment.

Next, differences in processing from the first embodiment will be described with reference to FIG.
When a transmission message is received from another in-vehicle terminal, the control unit 22 acquires vehicle information included in the transmission message in step S31, and acquires the current position, speed, and traveling direction of the opponent vehicle. Further, the control unit 22 simultaneously acquires the current position, speed, and traveling direction of the host vehicle. Then, an estimation is made of the time during which the vehicles are within a predetermined distance, that is, the time during which communication with the opponent vehicle is possible.

A method for estimating the communication possible time will be described with an example.
For example, when the opponent vehicle and the host vehicle face each other on the same road at a relative speed v [m / s], if the communicable distance (radius) of inter-vehicle communication is r [m], the communicable time is 2r / V [second]. For example, when the relative speed is 25 m / s and the communicable distance is 25 m, the communicable time is 2 seconds from (2 × 25) / 25.
In this embodiment, an example is given in which both vehicles are running facing each other, but the communicable time is calculated by another method based on the current position, speed, and traveling direction of both vehicles. You can also

  Here, it is assumed that the calculated communicable time is 2 seconds, the effective communication speed of inter-vehicle communication is 0.2 Mbps, and it takes 1 second to establish communication and extract charging facility information. Since one second can be used to transfer information, it can be seen that about 26 kilobytes of information can be transmitted in one second. Here, if both the vehicle information and the charging facility information are 512 bytes per record, it is understood that about 52 records can be transmitted. That is, one record of vehicle information and 51 records of charging facility information can be transmitted.

When the number of records that can be transmitted is determined, a transmission message with the maximum number of records is generated in step S33.
Thus, according to the present embodiment, by calculating the communicable time, it is possible to estimate the amount of information that can be transmitted, thereby preventing communication disruption.

(Third embodiment)
In the first and second embodiments, charging facility information is periodically transmitted to surrounding vehicles, but it is not useful to transmit information that is already shared by many vehicles. The third embodiment is an embodiment in which information considered to be already shared by many vehicles is extracted and transmitted with a reduced priority.

Differences between the in-vehicle terminal 20 according to the third embodiment and the first embodiment will be described.
An example of charging facility information stored in the facility information storage unit 21 is shown in FIG. In the third embodiment, the charging facility information includes a “reception count” field indicating the number of times the charging facility information is received from another vehicle, and a “transmission count” indicating the number of times the charging facility information is transmitted to another vehicle. "Field. The “reception count” is incremented when the facility ID and the information issue time coincide with the record already stored when storing the charging facility information in step S31. The “number of transmissions” is incremented when charging facility information is transmitted in steps S25 and S34. Other configurations are the same as those of the first embodiment.

Next, a difference in processing from the first embodiment will be described with reference to FIG.
When the transmission timing arrives, in step S24, the transmission information generation unit 23 extracts charging facility information to be transmitted to other in-vehicle terminals. At this time, a record with a small value in the reception count field is extracted with priority over a record with a large value. Further, a record with a small value in the transmission count field is extracted with priority over a record with a large value. For example, the number of receptions and the number of transmissions may be added, or weighted addition may be performed, and the results may be transmitted in ascending order. Further, only one of the reception count and the transmission count may be used.

  By comprising in this way, the information which is not transferred can be prioritized and transmitted to another vehicle-mounted terminal rather than the information which is transferred between the vehicle-mounted terminals. Information with a large number of receptions and transmissions can be estimated to be stored by more in-vehicle terminals, but information with a small number of receptions and transmissions may not have other in-vehicle terminals, It is desirable to transmit with priority. With this configuration, it can be expected that more in-vehicle terminals can share information that is not shared by many in-vehicle terminals.

(Modification)
The above embodiment is merely an example, and the present invention can be implemented with appropriate modifications within a range not departing from the gist thereof. For example, in the description of each embodiment, the information regarding the charging facility of the electric vehicle is cited as the facility information. For example, FIG. 13 is an example showing information on a fueling facility. As described above, the information sharing system according to the present invention can share any information as long as it is information about facilities scattered throughout the city.

DESCRIPTION OF SYMBOLS 10 Roadside device 11, 21 Facility information storage part 12, 24 Communication part 20 Car-mounted terminal 22 Control part 23 Transmission information generation part

Claims (11)

An information sharing system comprising a roadside device and a plurality of vehicles,
The roadside device is
It has facility information distribution means for transmitting facility information, which is information on facilities corresponding to the roadside device, to a vehicle passing through a predetermined point,
The vehicle is
First facility information receiving means for receiving the facility information from the roadside device;
Second facility information receiving means for receiving the facility information from another vehicle;
Facility information storage means for storing the facility information received by the first and second facility information receiving means;
Facility information transmitting means for extracting facility information from the facility information storage means and transmitting it to other vehicles;
Facility information request transmitting means for requesting transmission of facility information and transmitting a facility information request including information on the own vehicle to another vehicle;
Facility information request receiving means for receiving the facility information request from another vehicle;
Have
When the facility information transmission means has not received the facility information request from another vehicle, the facility information is extracted periodically by a predetermined algorithm and transmitted periodically, and the facility information request is received from another vehicle Extracts and transmits facility information based on information included in the facility information request,
Information sharing system. The facility information transmitting means transmits the extracted facility information without waiting for the arrival of a cycle when a facility information request is received from another vehicle.
The information sharing system according to claim 1. The facility information request transmitted by the facility information request means includes position information of the host vehicle,
The facility information transmitting means, when receiving the facility information request, extracts the facility information to be transmitted based on the position information included in the received facility information request,
The information sharing system according to claim 1 or 2. When the facility information transmission unit receives the facility information request from another vehicle, the facility information transmission unit calculates a communication possible time from the distance and relative speed with the other vehicle, and can communicate at the time. Extract and send a quantity of facility information,
The information sharing system according to claim 1. When the facility information transmitting means extracts and transmits the facility information, when the facility information storage means stores a plurality of facility information, the facility information transmitting means has received more than the number of facility information received from other vehicles. Priority is given to facility information with a small number of times, or priority is given to facility information with a small number of times of transmission over facility information with a large number of times of transmission
The information sharing system according to claim 1. The vehicle is an electric vehicle;
The facility corresponding to the roadside device is a charging facility for an electric vehicle.
The information sharing system according to claim 1. The facility information request transmitted by the facility information request means further includes a travelable distance of the host vehicle,
The facility information transmitting means further extracts the facility information to be transmitted by further using the travelable distance included in the received facility information request,
The information sharing system according to claim 6. The facility information request transmitting means transmits the facility information request to another vehicle when the storage amount of the own vehicle falls below a threshold value.
The information sharing system according to claim 7. The facility information request transmission means periodically transmits the facility information request to another vehicle when the storage amount of the own vehicle falls below a threshold, and when the storage amount is small compared to the case where the storage amount is large. Sending the facility information request in a shorter cycle;
The information sharing system according to claim 8. A vehicle-mounted terminal that receives facility information, which is information of a facility corresponding to the roadside device, from a roadside device or another vehicle-mounted terminal,
First facility information receiving means for receiving the facility information from the roadside device;
Second facility information receiving means for receiving the facility information from another in-vehicle terminal;
Facility information storage means for storing the facility information received by the first and second facility information receiving means;
Facility information transmission means for extracting and transmitting facility information to be transmitted to other in-vehicle terminals from the facility information storage means;
A facility information request means for transmitting a facility information request, which is information for requesting transmission of facility information, to another in-vehicle terminal;
Facility information request receiving means for receiving the facility information request from another in-vehicle terminal;
Have
When the facility information transmission means has not received the facility information request from another in-vehicle terminal, the facility information transmission means extracts the facility information by a predetermined algorithm and periodically transmits it, and receives the facility information request from another in-vehicle terminal. If so, the facility information is extracted based on the information included in the facility information request and transmitted.
In-vehicle terminal. An information sharing method performed by a roadside device, a first vehicle, and a second vehicle,
A first facility information transmitting step in which the roadside device transmits facility information, which is information of a facility corresponding to the roadside device, to the first vehicle passing through a predetermined point;
A facility information storage step in which the first vehicle receives and stores the facility information from at least one of the roadside device or another vehicle;
The facility information to be transmitted to the other vehicle by the first vehicle is extracted from the stored facility information and transmitted to a second facility information transmission step;
A facility information request transmitting step in which the second vehicle transmits a facility information request, which is information requesting transmission of facility information, to the first vehicle;
A facility information request receiving step in which the first vehicle receives the facility information request from the second vehicle;
Including
In the second facility information transmitting step, when the facility information request is not received from the second vehicle, the facility information is extracted and periodically transmitted by a predetermined algorithm, and the facility information is transmitted from the second vehicle. If the request is received, the facility information is extracted based on the information included in the facility information request and transmitted.
Information sharing method.

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