JP2011250021A - Vehicle group managing method and arrayed vehicle running communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arrayed vehicle running communication system that uses bidirectional communication to reduce a communication amount necessary for confirming reach, thereby suppressing a disruption in communication.SOLUTION: In the arrayed vehicle running method, a vehicle group composed of one leader and plural members is formed, the leader periodically transmits an HB packet, and the members each transmit an MR packet in response to the HB packet. When this is defined as one cycle of communication, in the HB packet, an ACK responding to communication from one member in a previous cycle, and in the MR packet, ACKs responding to communication from the leader in the present cycle and the communication from each member in the previous cycle are stored. Collective transmission of ACKs in each cycle can reduce a communication amount. Each vehicle transmits surrounding status information recognized by the vehicle, and autonomously controls running on the basis of status information obtained from communication and information obtained by sensors of the vehicle.

Description

  The present invention relates to a vehicle group management method and a convoy travel communication system.

  In recent years, platooning that automatically follows a preceding vehicle is studied. Such a platooning can release the driver from the driving operation and improve transportation efficiency and fuel efficiency by shortening the inter-vehicle distance. In such a row running, there has been a proposal for realizing more effective control by exchanging information necessary for running control by inter-vehicle communication.

As a first aspect of platooning using communication, there is a method of controlling the host vehicle in accordance with information transmitted from the preceding vehicle instead of or in combination with the radar. In this specification, platooning with such a mechanism is referred to as communication ACC (Adaptive Cruise).
Control) or follow-up running.

  As a further advanced aspect, there is a platooning system in which delivery confirmation is performed between vehicles performing platooning, and traveling control is performed while ensuring bidirectional communication. When two-way communication is secured, flexible and advanced control such as widening the distance between vehicles to be interrupted becomes possible, and the distance between vehicles can be shortened, the fuel consumption can be improved, and smooth tracking can be realized. In this specification, the row running with such a mechanism is referred to as cooperative running.

JP 2008-46820 A JP 2006-261742 A JP 2001-6099 A

By the way, in the case of a distributed communication system in which vehicles performing cooperative traveling individually transmit reception responses (ACKs) to all of the mutual communications, the amount of necessary communication increases with the increase in the number of vehicles that perform platooning Increase rapidly. When N vehicles are running in a row, the remaining N-1 vehicles return reception responses to information transmitted by a certain vehicle. number transmitted in the order of N ² in total each time of transmitting the information is needed.

  If the amount of communication increases in this way, radio wave interference occurs, which may adversely affect platooning control. Therefore, it is desirable to reduce the amount of communication required for delivery confirmation as much as possible so as not to cause communication interruption as much as possible.

  In addition, if communication interruption occurs during cooperative traveling, switching to follow-up traveling by communication ACC may be considered. This is because the communication ACC does not require delivery confirmation and also increases the inter-vehicle distance, thereby suppressing radio wave interference. However, it is not easy to widen the inter-vehicle distance by switching from cooperative running to follow-up running by communication ACC. Considering that it is difficult to completely suppress communication interruption, it is also desirable to reduce as much as possible the adverse effects when communication interruption occurs.

As described above, it is an object of the present invention to reduce the amount of communication necessary for delivery confirmation and suppress communication interruption as much as possible in a row running system that performs row running using two-way communication. Another object of the present invention is to minimize the influence of communication interruptions.

In order to achieve suppression of communication disruption, the vehicle group management method according to the present invention includes:
A platooning communication system that forms a vehicle group from a plurality of vehicles capable of bidirectional communication, with one vehicle as a leader and other vehicles as members, and performs platooning using communication between vehicles in the vehicle group Vehicle group management method in
A reader periodically sending information;
Each member returning a response to the information sent from the reader;
Including
The information transmitted from the leader includes a reception response indicating whether communication from each member in the previous cycle has been received,
The information transmitted from each member includes a communication response from the leader in the current cycle and a reception response indicating whether communication from another member in the previous cycle has been received,
Each vehicle is characterized by confirming the bidirectionality of communication based on a reception response included in information transmitted from another vehicle.

  As described above, a leader periodically transmits information in a vehicle group, and a member returns a response to the information, whereby a cycle that is a temporal boundary for communication in the vehicle group can be introduced. And if each vehicle transmits the reception response for 1 cycle collectively, duplication information, such as a packet header, can be reduced, Therefore The communication amount required in order to confirm the bidirectionality of communication can be reduced. Since the amount of communication can be reduced, the communication quality can be improved, that is, communication interruption can be suppressed.

In the present invention, the information that each vehicle periodically transmits includes the position of the vehicle, the identifier of the vehicle that constitutes the vehicle group, and the reception response for each vehicle that constitutes the vehicle group,
Each vehicle preferably autonomously performs traveling control based on information transmitted from another vehicle and information acquired by a sensor included in the own vehicle.
Here, it is preferable that the information periodically transmitted by each vehicle includes a traveling order in the vehicle group of the vehicles constituting the vehicle group. The traveling order in the vehicle group can be expressed by listing the identifiers constituting the vehicle group in the transmitted information according to the traveling order. Moreover, you may make it store in the information which links | relates and transmits the identifier of a vehicle, and driving | running | working order (number etc.). In addition, it is preferable that information regarding vehicles immediately before and after the vehicle group is included. Moreover, as a sensor with which the own vehicle is provided, it is preferable that the sensor which measures the position of the own vehicle and the sensor which measures the position of the object ahead of the own vehicle at least are included.

  As described above, information related to the vehicle group that the transmitting vehicle knows at the time of transmission is stored and transmitted in information that each vehicle periodically transmits, and specific control is performed on other vehicles. Since each vehicle autonomously makes a judgment of traveling control without issuing a command to instruct the vehicle, there is no need to transmit a control command. Furthermore, the communication required for confirming the delivery of the control command becomes unnecessary. Since the communication amount can be reduced in this way, it is possible to improve communication quality, that is, to suppress communication interruption. Even when information transmitted from another vehicle cannot be received temporarily, the travel control becomes possible when the next transmitted information is received, and the vehicle always travels based on the latest state information. There is also an advantage that control is possible.

  In the present invention, it is preferable that an upper limit is provided for the number of vehicles constituting the vehicle group.

By limiting the number of vehicles in the vehicle group, the amount of communication in the vehicle group can be reduced, and communication quality can be improved and communication interruption can be suppressed.

In the present invention, the vehicle located at the head of the vehicle group performs traveling control to follow the vehicle ahead of the vehicle group,
The inter-vehicle distance between the leading vehicle in the vehicle group and the vehicle in front of the vehicle group is preferably longer than the inter-vehicle distance in the vehicle group.

  As described above, the leading vehicle in the vehicle group follows the preceding vehicle, so that the plurality of vehicle groups can travel in a row as a whole. At this time, by making the distance between the head vehicle and the front vehicle in the vehicle group longer than the inter-vehicle distance in the vehicle group, it is possible to absorb changes in the speed, etc. in front of the vehicle group at this part. The impact on the group can be reduced. That is, even when communication disruption occurs in the front vehicle group, it is possible to limit the adverse effect only in the front vehicle group, and to prevent the rear vehicle group from being adversely affected by the communication disruption as much as possible.

  According to the present invention, since delivery confirmation can be performed between vehicles that travel in a row with a smaller communication volume, radio wave interference is reduced and communication interruption is suppressed.

  Furthermore, even when communication interruption occurs, the influence can be limited.

It is a figure explaining the ACK control system in this embodiment. It is a figure explaining the vehicle group cooperation driving | running | working in this embodiment, and the traveling control between vehicle groups. It is a figure explaining the control which isolate | separates a vehicle group before and behind a communication interruption vehicle when communication interruption generate | occur | produces in a vehicle group. It is a figure explaining the format of the data packet in this embodiment. It is a figure explaining the ACK control system in this embodiment in detail. It is a figure explaining the information source of the state information in this embodiment. It is a figure explaining the functional composition of vehicles in this embodiment. It is a figure explaining the state transition of the vehicle in this embodiment. It is a figure explaining the process which two vehicles which were drive | working by communication ACC merge and form one vehicle group. It is a figure explaining the process in which a vehicle group merges the vehicle which was carrying out the following driving | running | working with respect to the vehicle group by communication ACC. It is a figure explaining the process in which two vehicle groups merge and form one vehicle group. It is a figure explaining the competition solution process in case vehicle ID competes in a vehicle group. It is a figure explaining control when a communication member detaches from the inside of a vehicle group. It is a figure explaining control when a communication leader (leading vehicle) detaches from the inside of a vehicle group. It is a figure explaining the process when the vehicle in a vehicle group cancels | releases vehicle group cooperation driving | running | working. It is a figure explaining the process when the vehicle which does not have a communication function interrupts in a vehicle group. It is a figure explaining the method of detecting the communication function stop of the vehicle in a vehicle group. It is a figure explaining the process when the communication function of a vehicle stops within a vehicle group. It is a figure explaining the process when the vehicle in a vehicle group moves out of the communicable range. It is a figure explaining the process when radio wave interference generate | occur | produces in the vehicle group. It is a flowchart of the process common to all the vehicles performed at the time of packet reception. It is a flowchart of the process performed when the vehicle in a follow-up running state receives a packet and when a transmission timing arrives. It is a flowchart of the process which the vehicle in a vehicle group preparation state performs at the time of packet reception and transmission timing arrival. It is a flowchart of the process which the vehicle in a communication leader state performs at the time of vehicle group packet reception. It is a flowchart of the process which the vehicle in a communication leader state performs at the time of communication ACC packet reception. It is a flowchart of the process performed when the vehicle in a communication leader state arrives at transmission timing. It is a flowchart of the process which the vehicle in a communication member state performs at the time of vehicle group packet reception. It is a flowchart of the process performed when the vehicle in a communication member state arrives at transmission timing.

  This embodiment is a platooning system that forms a fleet and controls platooning by two-way communication within the fleet. The convoy travel control of this embodiment is a kind of cooperative traveling, but is referred to as vehicle group cooperative traveling in order to distinguish it from the prior art. In such a vehicle group cooperative traveling using two-way communication, more flexible and advanced platooning control is possible, and the inter-vehicle distance can be shortened. If communication disruption occurs during platooning with a reduced inter-vehicle distance, it is necessary to release the platooning control or change the control to follow-up driving to increase the inter-vehicle distance for safety. In this way, when performing platooning using two-way communication, the impact is significant if communication disruption occurs.

1. Outline Description of Convoy Traveling System According to this Embodiment In this embodiment, a leader who manages communication is selected, and the communication leader selects a communication member to form a group (vehicle group). Thereafter, the vehicle group is maintained and managed by regular communication between the communication leader and the communication member. In addition, the control leader in the vehicle group transmits a target control value to other vehicles, and each vehicle travels according to the transmitted target control value, so that the platooning is performed. As described above, the communication leader manages the communication in the vehicle group, and the control leader performs the platooning control in the vehicle group, thereby realizing the platooning by the vehicle group.

  In the present embodiment, the communication method and the vehicle group maintenance / management method described below are adopted within the vehicle group and between the vehicle groups, thereby realizing the suppression of the occurrence of the communication interruption and the reduction of the influence at the time of the communication interruption.

(A) Suppression of communication disruption In order to suppress the occurrence of communication disruption, it is necessary to efficiently perform radio communication necessary for platooning to suppress radio wave interference. The following method is adopted as a countermeasure.

(A-1) Improvement of ACK control (vehicle group communication system)
In order to confirm the bidirectionality of communication, it is necessary to return an ACK (reception response; sometimes referred to as loopback, but also referred to as ACK in this specification). In the distributed communication system in which each vehicle individually returns ACK in response to communication from other vehicles, the required communication amount increases rapidly (in the order of O (N ² )) as the number of vehicles increases. Thus, each vehicle in the vehicle group communication of the order of times N ² in the vehicle group each time to send a single message (excluding the communication ACK only) is required, leading to interference of radio waves.

In this embodiment, as shown in FIG. 1 (A), a communication leader (A in the figure) performs broadcast communication in the vehicle group, and in response to this, each member (B, C in the figure) returns a response. Adopt communication method. In this specification, communication from a communication reader is referred to as HB (HeartBeat), and communication from a communication member is referred to as MR (Membership Report). By adopting such a communication method,
Cycles can be defined for communications within a vehicle group. One cycle starts with HB from the communication reader and ends immediately before the next HB. The communication leader and the communication member can obtain a transmission right once in one cycle.

  The ACK control method will be described with reference to FIG. In FIG. 1B, “counter” identifies a message transmitted by each vehicle, and “ACK” indicates which message ACK is returned in the message transmission. As shown in the figure, the communication leader stores an ACK for communication from each member in the previous cycle and transmits an HB packet. The communication member stores an ACK for communication from the communication leader in the current cycle and an ACK for communication from other members in the previous cycle, and transmits an MR packet. Specifically, in cycle i, the communication leader stores an ACK for communication from the communication member in cycle i-1 and transmits an HB packet. Further, the communication member stores the ACK for the HB packet from the communication leader in cycle i and the ACK for the MR packet from other members in cycle i-1, and transmits the MR packet.

  In this way, by transmitting the ACK for each cycle together, it is possible to confirm the bidirectionality of mutual communication while reducing the number of communication. In this ACK control method, the number of communications for confirming the bidirectionality required when each vehicle transmits a message once is the same as the number of vehicle groups (O (N)). As described above, the number of communications for confirming the bidirectionality within the vehicle group can be reduced, so that radio wave interference can be suppressed and occurrence of communication interruption can be suppressed. Although a one-cycle delay occurs in the bidirectional confirmation of communication between members, there is no problem because new information can be sent every cycle by reducing the number of communication for ACK. Rather, in the conventional ACK method, N cycles are required for ACK confirmation and new information can be sent only every N cycles, whereas in this ACK method, new information can be transmitted every cycle while ACK confirmation is performed. There is an advantage that communication delay is reduced.

  Note that it is not necessary to limit communication for returning ACK to communication from a vehicle in the vehicle group, and ACK may be returned to communication from a vehicle outside the vehicle group. In the present embodiment, as will be described later, a vehicle positioned immediately in front of the vehicle group to which the host vehicle belongs (referred to as “a vehicle outside the vehicle group”) and a vehicle positioned immediately behind the vehicle group to which the host vehicle belongs. An ACK for communication from (referred to as “a vehicle outside the vehicle group”) is included.

(A-2) Cooperation by sharing state information (information transmission method)
In the present embodiment, each vehicle transmits the state information that the vehicle knows in an HB packet or MR packet. Each vehicle grasps changes in surrounding state information based on state information obtained from communication of surrounding vehicles and information obtained from sensors of the own vehicle, etc., and updates state information and performs control accordingly. . The state information is information necessary or useful for maintaining and managing a vehicle group, or information necessary or useful for platooning control. For example, the status information may include various information such as the possibility of bidirectional communication, whether the vehicle belongs to a vehicle group, the traveling order in the vehicle group, the position of each vehicle, the traveling direction, the traveling speed, and the acceleration. .

  In addition to the indirect command type control method in which each vehicle autonomously controls according to the latest status information by sharing the state information, the direct command type control method performs control according to an explicit control command from another vehicle. It is also possible to adopt. In the direct command type command transmission method, the leader sends a control command and the member returns ACK, or the leader sends a control command multiple times (the required number is calculated according to the packet arrival rate) and the member ACKs A method that does not return is conceivable. However, since the indirect command type control method has the following advantages, this embodiment adopts a control method based on state information sharing.

  First, in the state information sharing method, it is not necessary to send a control command or an ACK for the control command, so that the amount of communication can be reduced. The control command + ACK method requires two (two-way) communication for one control information transmission, and the control command multiple-time transmission method requires multiple communication. Also, it is difficult to design how many times to send in the multiple transmission system. In the state information sharing method, it is necessary to send state information. However, the state information itself is necessary information other than the control purpose, and is not extra data.

  In addition, if transmission fails in the method of transmitting the control command, the control command is retransmitted if it is within the valid time, but the situation may change during that time, and there is no guarantee that the information is actually valid . In that case, there is a possibility that useless broadcasting occurs or confusion occurs due to outdated information. On the other hand, in the state information sharing method, each vehicle always transmits the latest state information, so that problems such as useless broadcasting and information obsolescence do not occur.

  In the state information sharing method, the control state may vibrate when simply following the state information transmitted from another vehicle. For example, a certain vehicle may repeatedly join and leave the vehicle group. For this reason, it is desirable to avoid this problem by providing hysteresis in the change of the control state. Specifically, state information notified from a vehicle that is likely to cause vibration in the control state may be ignored for a certain period (exclusion period).

(A-3) Priority control of vehicle group communication Maintaining communication bidirectionality within a vehicle group is important for control of platooning. Therefore, it is preferable to suppress the communication disruption of the vehicle group communication by prioritizing the vehicle group communication (communication of the vehicle belonging to the vehicle group) over the communication of the vehicle not belonging to the vehicle group. For this reason, in this embodiment, the vehicle which received vehicle group communication suppresses communication.

Regarding the suppression method, the vehicle that intercepted the vehicle group communication waits for a certain period of time (Suppression
) Method and a reservation method in which a vehicle that intercepts vehicle group communication waits for a time specified by vehicle group communication. In other words, in the suppression method, the waiting time is set to the receiving vehicle (vehicle outside the vehicle group).
In the reservation method, the waiting time is determined by the transmitting vehicle (vehicle in the vehicle group). The suppression method does not require special control for vehicle group communication, so it is easy to implement.The reservation method requires additional information for vehicle group communication, but communication is ensured during vehicle group communication. Each has the advantage that it can be excluded.

  Moreover, regarding the communication content to be suppressed, it is conceivable that all communication is not performed and communication (information for entertainment, traffic information, etc.) except for vehicle control is not performed. Waiting for all communications increases the priority of vehicle group communication, but makes it impossible to exchange control information for vehicles that do not belong to the vehicle group. Therefore, what is necessary is just to determine the communication content to suppress by how much priority is given to vehicle group communication.

  In the present embodiment, a method that does not perform communication other than for control by a suppression method is employed.

(B) Reducing the impact of communication disruption In this embodiment, various methods such as (A) above are employed to suppress communication disruption, but it is still difficult to completely eliminate communication disruption. Thus, a design that reduces the influence of communication disruption is desired. As an influence due to the communication interruption, there is a change in the inter-vehicle distance or the like due to the switching of the platoon traveling control mode (switching from the vehicle group cooperative traveling to the tracking traveling).

  In the present embodiment, the following method reduces the adverse effect of communication interruption.

(B-1) Follow-up travel between vehicle groups In this embodiment, as shown in FIG. 2, an upper limit is set for the number of vehicles constituting one vehicle group, and follow-up travel is performed as a convoy travel control method between vehicle groups. adopt. In the vehicle group, platooning control is performed while performing bidirectional communication by the above-described vehicle group communication. In such vehicle group cooperative running, flexible control is possible, so that the inter-vehicle distance can be made relatively short.

  On the other hand, in convoy travel control between vehicle groups, follow-up travel in which a rear vehicle follows a front vehicle is employed. Here, the leading vehicle 22H of the following vehicle group 22 follows the last vehicle 21T of the front vehicle group 21 by communication ACC. The traveling control in the leading vehicle 22H is performed based on communication from the tail vehicle 21H and information obtained by a radar mounted on the own vehicle. In follow-up traveling, the inter-vehicle distance is longer because the control is not as flexible as the vehicle group cooperative traveling.

  Thus, by making the following travel between the vehicle groups, it is possible to prevent the influence of the communication interruption in a certain vehicle group from reaching the following vehicle group. For example, let us consider a case where communication interruption occurs in the front vehicle group 21 and all the vehicles in the front vehicle group are changed to follow-up traveling by communication ACC. In the forward vehicle group, it is necessary to increase the inter-vehicle distance in accordance with the shift to the follow-up traveling, so that the relative position between the vehicles changes. However, since the leading vehicle in the following vehicle group is originally following, it is not necessary to change the relative position (inter-vehicle distance) with the preceding vehicle. Of course, it is necessary to change the speed of the succeeding vehicle group in accordance with the speed change (deceleration) of the preceding vehicle. However, if the relative position between the vehicles does not change, it is considered that there is little anxiety given to the occupant.

(B-2) Car group division at the time of communication disruption in the vehicle group There are two possible situations in which communication disruption occurs in the vehicle group. One is a case where communication cannot be performed with a specific vehicle. As shown in FIG. 3 (A), when communication with a specific vehicle 31 constituting the vehicle group becomes impossible, as shown in FIG. 3 (B), from a vehicle positioned in front of the vehicle 31. The vehicle group 32 is divided into two vehicle groups, namely, a vehicle group 33 composed of vehicles located behind the vehicle 31. The rear vehicle group 33 follows the vehicle 31 by communication ACC. In this way, changes in the relative position between the vehicles can be minimized.

  In addition, there may be a situation in which communication becomes difficult due to communication congestion in the entire vehicle constituting the vehicle group. In this case, the communication leader excludes some of the communication members in the vehicle group from the vehicle group. By reducing the number of vehicles constituting the vehicle group, radio wave interference can be reduced and communication can be recovered. Since vehicles other than the excluded vehicles can maintain the vehicle group cooperative running, adverse effects at the time of communication interruption can be suppressed.

2. Control Request in the Convoy Traveling System According to the Present Embodiment The convoy travel system according to the present embodiment enables the following communication control. It should be noted that here, only the requirements to be satisfied by the main row traveling system are presented, and how to realize these requirements will be described later.

(A) Junction to the formation It is necessary that a new vehicle can join the formation by communication between vehicles. The confluence of platoons means that the number of vehicles belonging to the platoon increases, and includes the formation of a new vehicle group. The mode of joining the formation can be further divided into three [1] to [3].

[1] Formation of vehicle group:
This is a scenario in which vehicles that do not belong to a vehicle group join together to form a new vehicle group. An image of this scenario is shown in FIG. In the figure, a group of vehicles surrounded by a dotted line means a vehicle group.

[2] Participation in vehicle groups:
This is a scenario in which vehicles that do not belong to the existing vehicle group participate in the existing vehicle group and the vehicle group becomes larger. An image of this scenario is shown in FIG.

[3] Confluence of vehicle groups:
This is a scenario where two existing vehicle groups merge to form one large vehicle group. An image of this scenario is shown in FIG.

  Moreover, there is a conflict of vehicle IDs as a problem at the time of joining the formation.

[4] Conflict resolution of vehicle IDs It is ideal to assign individual IDs to all vehicles, but since there is a lot of waste, for example, IDs that do not overlap within a limited range should be adopted. Can be considered. Thus, since the vehicle ID is not necessarily unique, the vehicle ID may overlap (compete) among the vehicles in the vehicle group when the platoon joins. Therefore, a mechanism for resolving this vehicle ID conflict is also required.

(B) Departure from platoon [5] Departure due to lane change When a vehicle in the fleet leaves the platoon due to lane change, etc., the remaining vehicle can maintain the fleet and continue to platoon This is a request (see FIGS. 13 and 14).

(C) Separation of platoons When a vehicle incapable of communicating with a vehicle group is generated in the vehicle group, it is a request to separate the vehicle group into a front part and a rear part of the vehicle. Scenarios in which vehicles that cannot communicate in the vehicle group appear in the vehicle group can be divided into the following two scenarios.

[6] Cancellation by driver When a vehicle in the vehicle group collaborates, a vehicle that cannot communicate with the vehicle group appears in the vehicle group when one vehicle in the vehicle group releases the platooning by the driver (see FIG. 15). .

[7] Interruption of non-communication vehicle When a vehicle that does not have a communication function interrupts in the vehicle group, a vehicle that cannot perform vehicle group communication appears in the vehicle group (see FIG. 16).

(D) Communication disruption Even when communication disruption occurs in a vehicle group, it is required to continue to control safely. Communication interruption can be further classified into the following four modes.

[8] Communication function stop of specific vehicle When the communication function of a vehicle in the vehicle group is stopped, the vehicle group is separated into two parts, a front part and a rear part, rather than the vehicle. Note that the communication function is stopped when the transmission function is stopped (see FIG. 17A) and when the reception function is stopped (see FIG. 17B). In either case, the vehicle group is separated into two parts, a front part and a rear part, rather than the vehicle (FIG. 18).

[9] Movement out of communicable range Even when a vehicle in the vehicle group moves out of the communicable range, it is required to maintain the vehicle group with other vehicles (see FIG. 19).

[10] Generation of radio wave interference When radio wave interference (congestion) occurs, all the vehicles in the vehicle group cannot receive communications simultaneously and frequently. When radio wave interference occurs, it is necessary to suppress the entire communication amount. In this embodiment, the amount of communication is suppressed by reducing the number of vehicles constituting the vehicle group (see FIG. 20).

3. Detailed description of the convoy travel system according to the present embodiment (A) Communication leader / control leader decision policy In the convoy travel system according to the present embodiment, a communication leader selects communication members from within a communicable range to form a vehicle group. To do. Therefore, which vehicle is the communication leader is an important issue. The function satisfying the above requirements can be implemented at any position in the vehicle group in the communication leader, but it is preferable that the communication reader is located near the head or near the center of the vehicle group.

  When the communication leader is at the head and the vehicles behind the vehicle group are merged, the communication reader is not changed regardless of the number of vehicles to be merged and is stable. On the other hand, when vehicles in front of a vehicle group are merged, the communication leader is always changed, which is unstable.

  On the other hand, when the communication leader is near the center of the vehicle group, even if it is merged from either the front or the rear of the vehicle group, if the number of merged is small, the communication reader is not changed and stable, but the number of merged If it increases, the communication reader changes and becomes unstable.

  In this way, when considering merging into the vehicle group, if the communication leader is the leading vehicle and only merging from the rear is permitted (no merging from the front is performed), the communication leader is always unchanged and stable. I understand.

  We will also consider the impact of communication disruption. When the communication function of the communication reader is stopped, if the communication reader is at the head, one vehicle group can be autonomously formed by the second and subsequent vehicles. On the other hand, if the communication leader is near the center of the vehicle group, at least the vehicle group is divided into two (or the vehicle group is completely eliminated). Further, even when radio wave interference occurs, if the communication leader is at the top, it can be dealt with by removing the last vehicle in the vehicle group from the vehicle group. When the communication leader is in the vicinity of the center, complicated control of removing the vehicle equally from the beginning and the tail of the vehicle group is required under the condition that the communication leader is not changed.

  Thus, even if the influence at the time of communication interruption is taken into consideration, if the communication reader is at the head, the control is easy or stable.

  The communication leader selects a communication member from the communicable range to form a vehicle group. Here, the communicable range is not limited to a direct communicable range (a range in which communication can be performed by one hop) but may be within a communicable range by multi-hop communication. In the following, single-hop communication will be described as an example for the sake of simplification, but multi-hop communication may be used.

  As a result of the above examination, in this embodiment, control is performed so that the communication leader is always in the vehicle group. This makes it impossible to join from the front, but this demerit is small, and a great merit that the control becomes stable is obtained. However, this does not exclude the case where the communication leader is other than the head vehicle in the present invention, and the communication leader may be other than the head.

The control leader notifies a vehicle in the vehicle group of a target control value for performing the platooning in the vehicle group. Here, the target control value includes, for example, target acceleration information, steering angle information, brake operation information, and the like. In order to determine such a target control value, the control leader is preferably the head of the vehicle group. Therefore, when the communication reader is the head, it is preferable that the communication reader also serves as the control reader. On the other hand, when the communication leader is a vehicle near the center, it is preferable that the leading vehicle in the vehicle group becomes the control leader.

(B) Packet Format FIGS. 4A and 4B show examples of packet formats used in this embodiment. In the present embodiment, a vehicle having the same packet format is transmitted regardless of whether a vehicle belongs to a vehicle group or a vehicle that does not belong to a vehicle group, or a communication leader or a communication member.

  The source vehicle ID 401 stores the ID of the vehicle that generated this packet. In the present embodiment, the vehicle ID is expressed by 16 bits.

  The destination vehicle ID 402 stores the vehicle ID that delivers this packet. When broadcast communication is performed, an identifier (typically “0xFFFF”) indicating broadcast is stored in the destination vehicle ID 402.

  As the vehicle state 403, various information relating to the state of the transmission source vehicle is stored. The position information is typically included as the vehicle state. The transmission source position 404 stores position information expressed by a total of 70 bits including 28 bits of latitude information, 28 bits of longitude information, and 14 bits of height information. Various other vehicle states such as speed, traveling direction, and brake state can be adopted, but details thereof are omitted here.

  The control state 405 stores information indicating whether the vehicle cruising control state is “vehicle group cooperative travel”, “communication ACC travel”, “ACC travel”, or “manual travel”. The vehicle group ID 406 stores the ID of the vehicle group to which the host vehicle belongs. If the host vehicle does not belong to the vehicle group, “0” is stored. In the cycle 407, the cycle of the HB packet and the MR packet in the vehicle group communication is defined as one cycle, and the cycle number of the packet is stored. The type 408 stores whether this packet is an HB packet or an MR packet. When the host vehicle does not belong to the vehicle group, the cycle and type are blank (“0” is stored).

  FIG. 4B shows details of the traveling order vehicle ID 409 and the traveling order delivery confirmation 410. In the traveling order vehicle ID 409, the vehicles in the vehicle group and the front and rear vehicles outside the vehicle group are stored according to the traveling order. The traveling order delivery confirmation 410 stores ACK indicating whether or not communication from each of these vehicles has been received.

  Here, the upper limit of the number of vehicles that can belong to one vehicle group is N, and fields for N vehicles are prepared for vehicles in the vehicle group. When the number of vehicles in the vehicle group is less than N, the surplus travel order vehicle ID field is left blank (“0” is stored). The vehicle ID employs 16 bits, but the lower L bits (for example, 7 bits) of the vehicle ID are stored in the traveling order vehicle ID 409 of the vehicles in the vehicle group. This is because a conflict can be resolved with the vehicles in the vehicle group when the L bit of the vehicle ID competes as will be described later. In this way, the communication amount is reduced by shortening the vehicle ID. Of course, the value stored in the traveling order vehicle ID does not have to be the lower L bits of the vehicle ID. If the actual vehicle ID is K bits, it may be the value of L (<K) bits derived from this vehicle ID. That's fine.

  A vehicle that does not belong to the vehicle group generates and transmits a packet in which the ID of the vehicle in the vehicle group is blank.

-ACK control Here, the confirmation (ACK control) of the possibility of two-way communication within a vehicle group performed using the packet of the format mentioned above is demonstrated again. FIG. 5 shows the contents of messages exchanged in a certain cycle (here, cycle “23”) in a group of five vehicles A to E. The left side of FIG. 5 shows the contents of the HB packet transmitted from the communication reader, and the right side of FIG. 5 shows the contents of the MR packet transmitted from the communication member. The communication content shown in FIG. 5 is a simplified version of the packet format shown in FIG. First, the communication reader A broadcasts an HB packet storing the cycle number “23” to the vehicles in the vehicle group. Here, the traveling order vehicle ID stores the IDs of the vehicles constituting the vehicle group according to the traveling order. In the ACK for each vehicle, a value corresponding to whether or not communication from each vehicle has been received in the previous cycle (# 22) is stored. The ACK for the host vehicle may be indefinite, and in this embodiment, “1” is always stored, but this field may be used for other purposes.

  When the communication member (vehicle B here) receives the HB packet from the communication reader, the communication member transmits an MR packet in response thereto. Here, unicast communication is performed from the communication member B to the communication reader A. When the communication member B transmits the MR packet of the current cycle (# 23), regarding the ACK of the communication reader A, the communication member B indicates whether the communication from the communication reader A has been received in the current cycle (# 23). Regarding C to E, whether or not communication from each communication member has been received in the previous cycle (# 22) is stored. Note that the communication member B determines whether or not the communication from the other communication members C to E has been received by intercepting the MR packet transmitted by the other communication members C to E in the previous cycle (# 22). .

  In this way, the communication leader manages the communication cycle, and the communication member employs a communication method in which MR packets are transmitted once in each cycle in response to the HB packet from the communication leader. It is possible to transmit ACK for one cycle for all the vehicles together. As a result, the amount of communication required for confirmation of bidirectional communication can be reduced.

(C) Definition of state information Next, information (state information) about the current surroundings and the own vehicle stored in each vehicle will be described. The status information can be broadly divided into: information on the vehicle group to which the vehicle belongs, information on the vehicle group to which the vehicle does not belong (external vehicle group), a list of vehicles that should be ignored for a certain period of time (exclusion list), Contains initialization information.

  The belonging vehicle group information includes a vehicle group ID, a current cycle number, a vehicle ID relating to a vehicle in the vehicle group and a preceding vehicle / subsequent vehicle outside the vehicle group, presence / absence of ACK, vehicle information (position information, etc.) obtained from communication. . For vehicles in the vehicle group, the traveling order in the vehicle group is also stored.

  The information source is such information obtained from a vehicle in the vehicle group, communication from a preceding vehicle / subsequent vehicle outside the vehicle group, a sensor of the own vehicle, or the like. A more detailed information source is shown in FIG. In the figure, “self” means information defined by the own vehicle or information obtained from a sensor of the own vehicle, and “HB” means information (HB packet) from a communication reader. “MR” means information (MR packet) from a communication member, “outside” means information from outside the vehicle group, and “−”. This means that it is not necessary to acquire information. Information about vehicles outside the vehicle group may not be acquired by some vehicle group members, but of course, such information may be acquired and stored through communication from vehicles outside the vehicle group.

As shown in FIG. 6, the communication reader obtains information about vehicle group members from each member (MR packet), and obtains information from preceding vehicles and subsequent vehicles outside the vehicle group from communication from these vehicles. The communication members other than the tail acquire information about the communication leader and the traveling order of the communication members in the vehicle group from the communication leader (HB packet). Vehicle information such as ACK of communication members (whether communication from the vehicle in the previous cycle has arrived) and position information is acquired from each communication member (MR packet). In addition, the last communication member obtains ACK and vehicle information with the following vehicle outside the vehicle group from the vehicle.

  As external vehicle group information, a vehicle group ID, a vehicle ID of a communication reader, and a cycle number are stored. This is obtained by intercepting communications from vehicles belonging to the external vehicle group. This information is used in the vehicle in order to grasp what kind of vehicle group exists around.

  Among the external vehicle groups, for the vehicle group located immediately behind the vehicle group to which the host vehicle belongs, the ID of the vehicle constituting the vehicle group and the latest cycle number of communication received from these vehicles are stored. This information is used to perform the merge when the two-way communication with all the vehicles in the succeeding vehicle group has been confirmed when the vehicle groups merge.

  The exclusion list is a list of vehicles or vehicle groups that ignore state information transmitted for a certain period in order to prevent state vibration. For the vehicle group, the vehicle group ID, the vehicle ID of the communication leader, and the exclusion start time are stored. Moreover, about a vehicle, vehicle ID and exclusion start time are memorize | stored.

  The initial setting information includes the upper limit of the number of vehicles in the vehicle group (vehicle group size), the packet transmission rate (cycle time), the random standby time, the time to determine communication timeout, and the number of timeouts to determine communication interruption. , And the period excluded from the vehicle group target.

(D) Configuration of Vehicle FIG. 7 is a diagram showing functional blocks of the vehicle that constitutes the row running system according to the present embodiment. Each vehicle includes a vehicle travel control ECU (Electronic Control Unit) 701, an inter-vehicle communication device 705, a GPS device 707, a millimeter wave radar 708, an engine ECU 709, a brake ECU 710, a steering ECU 711, and the like. The vehicle travel control ECU 701 includes a control unit 702 that executes various processes described later, a storage unit 703 that stores state information and the like, a timer 704 that measures time, and the like. The inter-vehicle communication device 705 includes a communication unit 706 that performs wireless communication between vehicles. Any wireless communication system may be used, but a vehicle-to-vehicle communication system using the 700 MHz band (for example, ITC-FORUM RC-006) or a vehicle-to-vehicle communication system using the 5.8 GHz band (for example, ITC-FORUM). RC-005) can be used, but is not limited thereto. The GPS device 707 is a device for acquiring position information of the host vehicle from a GPS satellite or the like. It is not always necessary to receive a signal transmitted directly from a GPS satellite, but a signal from a relay device or the like may be received. The millimeter wave radar 708 is for measuring the position of the vehicle ahead. Therefore, a distance sensor using a radio wave having a wavelength other than millimeter waves, ultrasonic waves, or a distance sensor using a stereo camera may be used. The engine ECU 709, the brake ECU 710, and the steering ECU 711 are for acquiring the state of the host vehicle. In addition to this, information may be acquired from in-vehicle devices as necessary.

(E) Control flow Here, the process for satisfying the control requests [1] to [10] when the communication reader is designed as the leading vehicle in the vehicle group will be described. As described above, since the communication leader is the head, the growth of the vehicle group is only from the rear.

-State transition First, with reference to FIG. 8, the state transition between following driving | running | working, vehicle group cooperation driving | running | working, and manual driving | running | working is defined. When the following traveling function is enabled during manual traveling and the following traveling is actually possible using radar or communication, the state transits to the following traveling state. Actually, there are two cases of follow-up running by communication ACC and follow-up running by ACC. However, in the present invention, there is no essential difference, so these two states are collectively referred to as a follow-up running state. If it can be determined by communication with the radar that it is continuous with another vehicle and that bidirectional communication is possible in the following traveling state, the vehicle group preparation state is entered. The vehicle in the vehicle group preparation state waits for a random waiting time and then transitions to the communication leader state and transmits an HB packet. At this time, the following vehicle is selected as a vehicle group member. If the HB packet is received during the standby time and the own vehicle ID is included in the HB packet, the vehicle group member is transitioned to. Since only the succeeding vehicle is selected as a member when transmitting the HB packet, the preceding vehicle of the two consecutive vehicles eventually becomes the leader.

  Moreover, when the ID of the host vehicle is included in the HB packet from the preceding vehicle group during the follow-up running state, a transition is made to a communication member belonging to the preceding vehicle group.

  When the HB packet from the front vehicle group includes the ID of the own vehicle, the communication leader transitions to a communication member belonging to the front vehicle group.

  When communication with the preceding vehicle is interrupted or when the vehicle is at the head in the HB packet, the communication member shifts to the communication leader state and is behind the vehicle in the vehicle group. Is a communication member. Further, when the vehicle ID is not included in the HB packet or the vehicle group cooperative traveling mode is canceled by itself, the vehicle transits to the following traveling state.

  In any state, the driver can shift to the manual driving state by releasing the row driving by the driver.

-Flowchart Next, the process which the control part of vehicle travel control ECU performs is demonstrated with reference to the flowchart of FIGS. FIG. 21 shows common processing performed when a packet is received from another vehicle regardless of the state of the vehicle. The common process of FIG. 21 can be said to be a process of storing such information as state information when a packet from outside the vehicle group is received, and a process of suppressing communication unrelated to travel control.

  When a packet from another vehicle arrives in the standby state (S2102), communication without running control for a predetermined time is refrained (S2104). In the present embodiment, the vehicle side that has received a packet relating to platooning from another vehicle suppresses communication for a predetermined time. Of course, the communication including the traveling control is continuously transmitted as usual.

  Then, it is determined whether the received packet is a vehicle group packet from a vehicle in the vehicle group to which the host vehicle belongs (S2106). The received packet is a vehicle group packet from a vehicle group to which the vehicle does not belong (if the vehicle does not belong to the vehicle group, all vehicle group packets are applicable), or a packet other than the vehicle group packet ( If it is a communication ACC packet), a negative determination is made (NO in S2106). If it is not a packet from the affiliation vehicle group, it is determined whether the transmission source of the received packet is the following vehicle and communication of the own vehicle can be received (whether the ACK bit is set) (S2108). Note that the following vehicle means a vehicle immediately behind the host vehicle. Whether or not the transmission source is a subsequent vehicle can be determined by whether or not the vehicle outside the vehicle group included in the received packet is the host vehicle. If the transmission source is a subsequent vehicle and communication from the own vehicle can be received, this vehicle is registered in the status information as a subsequent vehicle outside the vehicle group of the belonging vehicle group information (S2110). Since the determination in S2108 is performed only when a packet from a vehicle other than the vehicle group to which the host vehicle belongs is received, only when the host vehicle is at the end of the vehicle group when the host vehicle belongs to the vehicle group. This registration is performed.

  Similarly, it is determined whether the transmission source of the received packet is a preceding vehicle and the communication of the own vehicle can be received (S2112). A preceding vehicle is a vehicle located in front of the host vehicle. Whether the transmission source of the received packet is a preceding vehicle is based on the state of the own vehicle (the head of the vehicle group or the non-vehicle group), and the position information of the transmission source included in the packet and the vehicle ahead that can be acquired It can be determined by whether or not the position information of the two matches. That is, if the position information of the transmission source included in the received packet matches the position information of the preceding vehicle that can be acquired by the radar of the own vehicle, it can be determined that the packet is from the preceding vehicle (YES in S2112). In this case, this vehicle is registered in the state information of the own vehicle as the preceding vehicle outside the vehicle group of the belonging vehicle group information (S2114). Note that the determination in S2112 is performed only when a packet is received from a vehicle other than the vehicle group to which the host vehicle belongs. Therefore, when the host vehicle belongs to the vehicle group, only when the host vehicle is the head of the vehicle group, this Registration is performed.

  Further, it is determined whether the received packet (packet from other than the belonging vehicle group) is a vehicle group packet (S2116). If the received packet is a vehicle group packet (S2116-NO), information relating to this vehicle group is registered in the external vehicle group information as state information (S2118).

  If the received packet is not a vehicle group packet from the belonging vehicle group (S2106-NO), the process proceeds to step S2120 after performing the processing of S2108 to S2118. On the other hand, if the received packet is a vehicle group packet from the belonging vehicle group (S2106-NO), the process directly proceeds to step S2120. In step S2120, it is determined whether or not the transmission source vehicle is a vehicle that exists in the exclusion list or a vehicle that belongs to the vehicle group that exists in the exclusion list. If the vehicle is included in the exclusion list (S2120—YES), further processing is performed. Return to the standby state without If not in the exclusion list, it is determined whether the received packet is a vehicle group packet (S2122). When it is a vehicle group packet, the process proceeds to a vehicle group packet reception process, and when it is not a vehicle group packet (when it is a communication ACC packet), the process proceeds to a communication ACC packet reception process. The subsequent processing differs depending on the state of the vehicle. Therefore, below, a processing flow is demonstrated according to the state of a vehicle. It should be noted that the following flowchart includes processing not only when a packet is received but also when transmission timing arrives.

  FIGS. 22 to 28 are flowcharts showing processes performed when a vehicle group packet is received, when a communication ACC packet is received, and when a transmission timing arrives in each state (following running state, vehicle group preparation state, communication leader, communication member). is there. As described above, it should be noted that when the vehicle group packet and the communication packet are received, the common processing shown in FIG. 21 is executed as preprocessing. Hereinafter, it will be described that the functions [1] to [10] shown in “2. Control request in the row running system according to the present embodiment” can be realized by following the flowcharts of FIGS.

[1] Formation of Vehicle Group As shown in FIGS. 9A and 9B, a control scenario in which a vehicle group is formed by confirming the bidirectionality of communication between two vehicles that are following the vehicle by communication ACC. It is.

  First, each of the vehicles A and B travels while periodically transmitting a communication ACC packet including a vehicle ID and position information. When vehicle B approaches from behind vehicle A and receives a communication ACC packet (S2102, S2106-NO) of vehicle A, the position information contained in the packet of vehicle A and the millimeter wave radar of the own vehicle are obtained. The position information of the preceding vehicle coincides and it can be seen that the vehicle A is a preceding vehicle of the vehicle B (S2112—YES). Therefore, the vehicle B registers the vehicle A as a preceding vehicle outside the vehicle group (S2114). When the transmission timing arrives at the vehicle B (S2210), as shown in FIG. 9A, the preceding vehicle outside the vehicle group is the vehicle A, and a communication ACC packet with an ACK for the vehicle A is generated and broadcasted. (S2212).

  The vehicle A that has received the communication ACC packet (S2102, S2106-NO) from the vehicle B has the preceding packet outside the vehicle group as its own vehicle and also has ACK (S2108-YES). It is registered as an outer succeeding vehicle (S2110). When the transmission timing arrives at the vehicle A (S2210), as shown in FIG. 9A, the subsequent vehicle outside the vehicle group is the vehicle B, and a communication ACC packet with ACK for the vehicle B is generated and broadcast. Transmit (S2212).

  Since the vehicle A is the communication ACC packet received from the vehicle B, the own vehicle is a preceding vehicle outside the vehicle group and ACK is also present, so the received communication ACC packet is from the following vehicle, and the ACK (S2206 YES), the state transitions to the vehicle group preparation state. Similarly, vehicle B also receives a communication ACC packet from the preceding vehicle because its own vehicle is a subsequent vehicle outside the vehicle group and ACK is present in the communication ACC packet received from vehicle A. Since it can be determined that there is an ACK (YES in S2208), the state transitions to the vehicle group preparation state. As described above, the vehicle A and the vehicle B make a transition to the vehicle group preparation state by confirming that two-way communication can be performed and the two vehicles are continuous during the follow-up traveling by the communication ACC. .

  In the flowchart of FIG. 22, it is shown that the state transition is performed once bi-directional communication possibility and continuity are confirmed even once (the state transition is performed as soon as either S2206 or S2208 is established). It is also preferable to perform a state transition when this condition is satisfied several times in succession because it is excellent in terms of stability.

  The vehicles A and B that have shifted to the vehicle group preparation state obtain the transmission timing after waiting for a random time (S2312). If the vehicle A first obtains the transmission timing, the vehicle A changes state to the communication reader and edits the state information (S2314). Here, the editing of the state information includes selecting vehicles constituting the vehicle group. In the present embodiment, in order to set the communication leader at the head of the vehicle group, a vehicle located behind the communication reader is included in the vehicle group. Since the vehicle B is behind the vehicle A, the created vehicle group information stores a vehicle group in which the vehicle A is a communication leader and the vehicle B is a communication member. Further, with reference to the external vehicle group information obtained by the common processing, the vehicle group ID and the cycle in the vehicle group to which the host vehicle belongs are determined so as not to overlap with other vehicle groups (S2318). Then, the vehicle A broadcasts the HB packet shown in FIG. 9B as a communication leader (S2318). Vehicle B in the vehicle group preparation state receives this HB packet (S2302, S2304-HB), and since this HB packet is from the preceding vehicle and there is also an ACK confirmation (S2306-YES), vehicle A It becomes clear that it became a member of the vehicle group having as a communication leader. Therefore, the vehicle B changes its state to a communication member and updates the state information (S2308).

  In addition, when the vehicle B located behind obtains the transmission timing first, since the communication member is selected only from the vehicle located behind, the vehicle B is a communication leader of a vehicle group composed only of the own vehicle. Become. Although vehicle B transmits an HB packet as a communication leader, vehicle B is not a preceding vehicle for vehicle A (S2306-NO), and the vehicle group preparation state is continued. Eventually, the vehicle A obtains the transmission timing and forms a vehicle group including the vehicle B as a member, as described above. Since the vehicle B that has been the communication leader also finds the ID of the own vehicle in the HB packet transmitted from the other vehicle group, the vehicle B changes to a communication member of the vehicle group that uses the vehicle A as the communication leader (S2404). S2406-S2408-S2410). Therefore, even if any of the vehicle A and the vehicle B in the vehicle group preparation state obtains the transmission timing first, the vehicle group finally formed is the same.

In this way, when the bidirectionality and continuity of communication are confirmed between the vehicle A and the vehicle B that have been following following by the communication ACC, the vehicle A in front is composed of two vehicles with the communication leader as the communication leader. A vehicle group will be formed. Vehicle A and vehicle B that form a vehicle group regularly exchange HB packets and MR packets that include vehicles A and B in the vehicle group list, and perform vehicle group cooperative travel while confirming communication bidirectionality. be able to.

[2] Participation in vehicle group As shown in FIGS. 10A and 10B, this is a scenario in which a vehicle following the vehicle group through communication ACC joins the vehicle group and the vehicle group becomes larger. .

  First, as shown in FIG. 10 (A), a situation is considered in which a vehicle D that performs follow-up traveling by communication ACC exists behind a vehicle group composed of vehicles A to C. In this situation, the vehicle D recognizes the vehicle C as a vehicle outside the vehicle group (S2112-S2114), and transmits a communication ACC packet (S2212). That is, in the communication ACC packet transmitted by the vehicle D, the vehicle C is stored as the preceding vehicle outside the vehicle group, and “ACK” is stored. When the vehicle C receives the communication ACC packet, the vehicle C recognizes that the vehicle D is a subsequent vehicle outside the vehicle group (S2108-S2110). The vehicle C stores the vehicle D in the subsequent vehicle outside the vehicle group and transmits an MR packet (S2808). Receiving this MR packet, the communication reader A recognizes that the subsequent vehicle outside the vehicle group is the vehicle D (S2404-S2432-S2434-S2436).

  Processing when the communication leader (vehicle A) recognizes that the subsequent vehicle outside the vehicle group is the vehicle D in this way and receives a communication ACC packet from the vehicle D will be described. The communication reader (S2502) that has received the communication ACC packet has established two-way communication between the vehicle D, which is the subsequent vehicle outside the vehicle group, and the vehicle C, which is the last vehicle in the vehicle group (S2504-YES). If the number of vehicles in the vehicle group has not reached the maximum (S2506-YES), the vehicle D is registered at the tail of the vehicle group (S2508). Then, at the next transmission timing, the communication leader includes the vehicle D in the vehicle group list and transmits the HB packet.

  When the following vehicle D receives the HB packet from the vehicle A, first, since the received packet is from the preceding vehicle and ACK is present (S2208-YES), the state transits to the vehicle group preparation state. When the HB packet is received in the vehicle group preparation state (S2304-HB), since this HB packet is from the preceding vehicle and there is also an ACK confirmation (S2306-YES), transition to the communication member state (S2308). At this time, the state information is updated in response to the own vehicle belonging to the vehicle group.

  In this way, when the vehicle D that has followed the vehicle group by the communication ACC confirms the possibility of two-way communication and continuity between the vehicle group and the vehicle D, the vehicle D joins the vehicle group. Can do.

[3] Merging of vehicle groups As shown in FIGS. 11A and 11B, a scenario in which two vehicle groups that follow the vehicle group by communication ACC merge to form one large vehicle group. It is.

  It can be seen in the same manner as described above that the last vehicle C in the front vehicle group 1101 and the first vehicle D in the rear vehicle group 1102 are continuous. By receiving the MR packet transmitted by the vehicle C, each vehicle in the forward vehicle group 1101 can recognize that the subsequent vehicle outside the vehicle group is the vehicle D. Similarly, by receiving the HB packet transmitted by the vehicle D, each vehicle in the rear vehicle group can recognize that the preceding vehicle outside the vehicle group is the vehicle C.

When the communication reader A receives an MR packet from a communication member in the rear vehicle group, the process proceeds to S2404-S2406-S2422-S2424, and the vehicle group list included in the MR packet is registered in the rear vehicle group information. If an HB packet is received from the communication leader of the rear vehicle group, the process proceeds from S2404 to S2406 to S2408 to S2412 to S2422 to S2424, and the same process is eventually performed. Note that the determination in S2412 is a determination as to whether or not an HB packet (having a different vehicle group ID) has been received from a communication member that the communication reader A has recognized as belonging to the same vehicle group. Determined. The communication reader stores, as the rear vehicle group information, which vehicle constitutes the rear vehicle group and whether communication from each vehicle constituting the rear vehicle group can be received. When an HB packet is received from the rear vehicle group (S2425-YES), communication can be received from all the vehicles belonging to the rear vehicle group (S2426-YES). If the number does not reach the number (S2408-YES), each vehicle constituting the rear vehicle group is registered at the end of the belonging vehicle group information (S2430). Further, the rear vehicle group is registered in the exclusion list so that the state information is not changed by the information from the rear vehicle group for a certain period. When the transmission timing arrives, the communication reader transmits an HB packet including vehicles A to F in the vehicle group list (S2612).

  When the communication leader D of the rear vehicle group receives the HB packet from the vehicle A, it discovers the ID of the own vehicle in the HB packet of the other vehicle group, so that the state transitions to the communication member (S2404-S2406-S2408-S2410). ). Further, the communication members E and F of the rear vehicle group that have received the HB packet from the vehicle A find the ID of the own vehicle in the HB packet of the other vehicle group, so change the belonging vehicle group (S2704 to S2706). -S2708-S2710). Further, the communication members E and F register the original vehicle group in the exclusion list so as not to cause a state change due to information from vehicles belonging to the same vehicle group for which the change of the belonging vehicle group has not been completed. To do.

  In this way, when continuity and bidirectionality of communication are confirmed between the two vehicle groups 1101 and 1102 that have been following by the communication ACC, the two vehicle groups 1101 and 1102 are combined into one. It can join the vehicle group 1103.

[4] Conflict Resolution of Vehicle ID In a packet used for communication, an ID related to a vehicle in a vehicle group is expressed by a bit number (for example, 7 bits) shorter than the original number of bits (for example, 16 bits) (see FIG. 4 (B)). This is a device for reducing the data amount of the communication packet. In the first place, it is not guaranteed that there is no overlap in the vehicle ID, but even if the 16-bit vehicle ID does not overlap, the probability that a collision will occur increases if only the lower 7 bits are used. When a vehicle ID with a reduced number of bits used in such a vehicle group collides, it is necessary to reset the vehicle ID to resolve the conflict.

  Consider an example in which a vehicle group is composed of eight vehicles as shown in FIG. In the figure, “ho” means that the upper 9 bits are “h” and the lower 7 bits are “o” in all 16-bit vehicle IDs. In this example, the lower 7 bits of the communication reader and the sixth vehicle collide with “g”, and the lower 7 bits of the fourth and seventh vehicles collide with “e”.

  In this embodiment, the communication leader does not reset the vehicle ID, and the communication member resets the lower 7 bits of the vehicle ID to resolve the conflict. That is, the communication reader does not determine whether the vehicle IDs in the vehicle group list are duplicated. On the other hand, the communication member determines whether two or more IDs (lower 7 bits) of the host vehicle are registered in the HB packet received from the communication reader (S2726). Here, when the competition of the vehicle ID has occurred, the lower 7 bits of the vehicle ID of the host vehicle are reset (S2730). The lower 7 bits of the new vehicle ID are selected at random from values other than “g”, “h”, “w”, “e”, “m”, and “o” included in the HB packet. Since it is set at random, there is a possibility that the collision will occur again, but the conflict can be finally solved by repeating the resetting process.

  Further, since the MR packet from the communication member with which the vehicle ID is competing cannot be determined as to which communication member is information, if the vehicle ID of the transmission source of the received MR packet is in conflict, the MR packet Is ignored (S2718). On the other hand, even if the vehicle ID of the communication leader is competing with other members, the packet from the communication leader can be determined from the packet type (HB packet), so such processing is necessary for the HB packet. There is no.

  In this way, it is possible to resolve the conflict when the vehicle ID collides within the vehicle group. If conflict resolution is ensured, the amount of communication data can be reduced using a shortened vehicle ID in the vehicle group.

  Although the amount of communication data can be reduced by using the shortened vehicle ID, it is inevitable that overhead for resolving the conflict occurs. In cases where the amount of communication data does not matter or in an environment where overhead is not allowed, it can be said that it is preferable not to use a shortened vehicle ID even in a vehicle group.

[5] Departure due to lane change In this scenario, when a vehicle constituting a vehicle group leaves the platoon due to a route change or the like, the fleet is maintained while the vehicle group is maintained with the remaining vehicle.

  First, a case where a communication member leaves due to a route change will be described with reference to FIGS. Here, the case where the vehicle C changes the route from the vehicle group comprised of five vehicles A to E is considered. At this time, the vehicles constituting the vehicle group and the traveling order thereof are stored in the vehicle group list notified by communication, so that each vehicle in the vehicle group can grasp the situation of the vehicle group. It can be seen that each vehicle has a vehicle group composed of five vehicles in the order of vehicles A, B, C, D, and E by the HB packet transmitted from the communication reader A. The position information of each vehicle is also stored in the vehicle group packet.

  On the other hand, each vehicle can know the position of the vehicle ahead by radar. When the vehicle C changes the route, the vehicle D can detect from the radar that the vehicle ahead is located at (Xb, Yb). Here, referring to the position information obtained from the vehicle group packet, it can be seen that the vehicle located at (Xb, Yb) is the vehicle B. That is, it can be seen that the vehicle D is located immediately behind the vehicle B, and therefore, it can be seen that the vehicle C located between them has left due to a route change or the like. Therefore, the vehicle D is updated when the vehicles A, B, D, and E form a vehicle group in this order except for the vehicle C that has left the belonging vehicle group information. This process is a process performed in S2720 or S2728. When the transmission timing arrives at the vehicle D, the vehicle D stores the state information held by the own vehicle, that is, the vehicle group list that the vehicle group is composed of the vehicles A, B, D, and E in the MR packet. Send.

  When receiving the MR packet from the vehicle D, the communication reader A recognizes that the vehicle C has left the vehicle group and updates the state information (S2404-S2432-S2434-S2436). When the transmission timing arrives at the communication reader A, the communication reader stores in the HB packet the state information held by the vehicle, that is, the vehicle group list that the vehicle group is composed of the vehicles A, B, D, and E. Transmit (S2612).

  The vehicle group member who has received the HB packet from the communication reader A can recognize from the vehicle group list that the vehicle C has left the vehicle group.

In this way, even when the vehicles in the vehicle group leave due to a route change or the like, the vehicle group can be maintained by the remaining vehicles (S2728).

  Next, with reference to FIGS. 14A and 14B, a case where the communication leader leaves due to a route change or the like will be described. At this time, vehicle B, which is a communication member traveling immediately after the communication leader in the vehicle group, cannot specify the preceding vehicle in the vehicle group by the radar. If the preceding vehicle cannot be specified when the transmission timing arrives at vehicle B, vehicle B transitions to a communication leader (S2802-S2804-S2810). Then, using the own vehicle as a communication leader, among the vehicles included in the original vehicle group, all vehicles positioned behind the own vehicle are used as communication members to generate a new vehicle group and register it as belonging vehicle group information ( S2812). A vehicle group ID and a cycle that do not overlap with the external vehicle group are selected (S2814), the original vehicle group is registered in the exclusion list (S2816), and an HB packet is created and broadcast (S2818). Vehicles B to E are stored in the vehicle group list of the HB packet.

  In the vehicles C to E that have received the HB packet transmitted from the vehicle B, the vehicle group ID of the HB packet is different from the vehicle group ID to which the vehicle belongs, but the vehicle group ID of the vehicle is included in the vehicle group list of the HB packet. It can be seen that the vehicle ID exists. Therefore, since it can be recognized that the own vehicle is a member of a different vehicle group than before, the vehicle group information is edited according to the received HB packet (S2704-S2706-S2708-S2710). Further, in order to avoid the vibration of the state due to the information from the original vehicle group, the original vehicle group is added to the exclusion list (S2912).

  Thus, even when the communication leader leaves the vehicle group due to a route change or the like, the communication member who has traveled second becomes a new communication leader and can maintain the vehicle group.

[6] Releasing by driver When one of the vehicles in the group cancels the vehicle group platooning and shifts to manual driving or communication ACC driving during the vehicle group cooperative driving, It is a scenario of maintaining a platoon.

  As shown in FIG. 15, consider a case where the vehicle D cancels the vehicle group cooperative traveling by the driver's operation when the seven vehicles A to G form the vehicle group. The vehicle D notifies the surrounding vehicles that the vehicle group cooperative traveling has been canceled by the communication function. The communication information transmitted by the vehicle D at this time stores the vehicle's convoy travel mode ("Manual" or "Communication ACC") in the control information, and the travel order list includes the vehicle C as the front vehicle outside the vehicle group, The vehicle E is stored in the rear vehicle outside the vehicle group and transmitted.

  When the communication leader of the vehicle group receives a packet for notifying the cooperative running cancellation by the driver's operation (S2609-YES), this vehicle to the following vehicle outside the vehicle group is deleted from the belonging vehicle group information and is included in the exclusion list. Registration is performed (S2611). As a result, the vehicle D and the vehicle located behind the vehicle D are excluded from the vehicle group, and the vehicle group in which the vehicle A is a communication leader includes only the vehicles A to C. And a communication leader notifies that the member which comprises a vehicle group changed with respect to another vehicle by storing and transmitting only vehicles A, B, and C in the vehicle group list | wrist of an HB packet.

On the other hand, when the communication member receives the packet for notifying the cooperative traveling cancellation by the driver operation, it is determined whether the vehicle that has performed the cancellation is a preceding vehicle (S2807). When the vehicle located in front of the host vehicle cancels the cooperative travel, the host vehicle transitions to the communication leader (S2810). In this case, the vehicle E changes to a communication leader. Then, a new vehicle group is generated with the vehicles F and G behind the host vehicle as communication members and registered as belonging vehicle group information (S2812). A vehicle group ID and a cycle that do not overlap with the external vehicle group are selected (S2814), the original vehicle group is registered in the exclusion list (S2816), and an HB packet is created and broadcast (S2818). Vehicles E, F, and G are stored in the vehicle group list of the HB packet.

  In the vehicles F and G that have received the HB packet transmitted from the vehicle E, the vehicle group ID of the HB packet is different from the vehicle group ID to which the vehicle belongs, but the vehicle group ID of the HB packet is in the vehicle group list of the HB packet. It can be seen that the vehicle ID exists. Therefore, since it can be recognized that the vehicle is a member of a different vehicle group than before, the belonging vehicle group information is edited in accordance with the received HB packet (S2704-S2706-S2708-S2710). Further, in order to avoid the vibration of the state due to the information from the original vehicle group, the original vehicle group is added to the exclusion list (S2912).

  In this way, even when the driver cancels the vehicle group coordinated driving in any vehicle in the vehicle group, the vehicle group is separated at that position to generate the front vehicle group and the rear vehicle group, thereby generating the vehicle group. Coordinated driving can be performed.

[7] Interruption of non-communication vehicle This is a scenario in which a vehicle group is separated before and after the non-communication vehicle when a vehicle having no communication function is interrupted in the vehicle group.

  As shown in FIG. 16, consider a case where a vehicle X that does not have a communication function is interrupted in front of a vehicle D when a vehicle group including six vehicles A to F is formed. At this time, in the vehicle group list notified by communication, the traveling order with the vehicles constituting the vehicle group is stored, so that the situation in the vehicle group can be grasped. Here, it can be seen that the vehicle group is composed of six vehicles in the order of vehicles A, B, C, D, E, and F. The position information of each vehicle is also stored in the vehicle group packet.

  On the other hand, each vehicle can know the position of the vehicle ahead by radar. When the non-communication vehicle X is interrupted in front of the vehicle D, the position of the front vehicle obtained by the radar and the position (Xc, Yc) of the front vehicle (vehicle C) obtained by the vehicle group communication are contradictory. Become. That is, the vehicle D cannot specify the preceding vehicle.

  When the transmission timing arrives at vehicle D, which is a communication member, vehicle D cannot make a transition to the communication leader because it cannot identify the preceding vehicle (S2804-S2810). Then, using the own vehicle as a communication leader, among the vehicles included in the original vehicle group, all vehicles positioned behind the own vehicle are used as communication members to generate a new vehicle group and register it as belonging vehicle group information ( S2812). A vehicle group ID and a cycle that do not overlap with the external vehicle group are selected (S2814), the original vehicle group is registered in the exclusion list (S2816), and an HB packet is created and broadcast (S2818). Vehicles D, E, and F are stored in the vehicle group list of the HB packet.

  In the vehicles E and F that have received the HB packet transmitted from the vehicle D, the vehicle group ID of the HB packet is different from the vehicle group ID to which the host vehicle belongs, but the vehicle group ID of the HB packet is in the vehicle group list of the HB packet. It can be seen that the vehicle ID exists. Therefore, since it can be recognized that the own vehicle is a member of a different vehicle group than before, the vehicle group information is edited according to the received HB packet (S2704-S2706-S2708-S2710). Further, in order to avoid the vibration of the state due to the information from the original vehicle group, the original vehicle group is added to the exclusion list (S2912).

In addition, the vehicle A (the communication leader of the original vehicle group) that has received the HB packet transmitted from the vehicle D has the received packet that is an HB packet from another vehicle group (S2404-NO, S2406-YES). It can be seen that the vehicle registered as the communication member in the vehicle group information of the vehicle is the transmission source (YES in S2412). Since the source vehicle C of the received HB packet is the third and subsequent vehicles in the original vehicle group (S2416-NO), the vehicle C and the vehicles E and F behind it are deleted from the vehicle group and the vehicles A and B are deleted. , C is updated so as to include only C in the vehicle group list (S2420). In addition, when the traveling position of the communication leader of the separated succeeding vehicle group is the second (S2416-YES), since the communication leader A is only one vehicle group, the state shifts to the vehicle group preparation state ( S2418). In either case, a new vehicle group is added to the exclusion list so as not to cause vibration of the state with the separated vehicle group (S2414).

  The vehicles B and C that have received the HB packet including the vehicles A to C in the vehicle group list from the communication reader A recognize that the vehicle constituting the vehicle group has changed, and update the vehicle group information. .

  As described above, even when a vehicle having no communication function is interrupted in the vehicle group, the vehicle group is separated at the position to generate the front vehicle group and the rear vehicle group, and the vehicle group cooperative traveling can be performed.

[8] Communication function stop of specific vehicle This is a scenario in which the vehicle group is separated before and after the vehicle when the communication function of the specific vehicle in the vehicle group stops. There are two types of communication function stop: transmission function stop and reception function stop. First, in each case, how the other vehicle detects the function stop will be described.

  FIG. 17A is a diagram illustrating a case where the transmission function of the vehicle D in the vehicle group composed of the vehicles A to G is stopped. It can be seen that the vehicles in the vehicle group do not receive communication from the vehicle D. Therefore, the absence of ACK is stored for the vehicle D in the HB packet or MR packet and transmitted. Further, since no ACK is stored for the vehicle D in the packet from another vehicle, each vehicle in the vehicle group cannot receive communication from the vehicle D, not only the own vehicle but all the vehicles in the vehicle group. I understand that. As described above, when vehicles (or all vehicles) in a vehicle group within a vehicle group transmit a vehicle group packet with no ACK for the vehicle D, it is determined that the communication function of the vehicle D has stopped. it can. Note that this determination is not performed in only one cycle, but it is preferable to determine that the transmission function of the vehicle C is stopped when no ACK from the vehicle D continues for a predetermined cycle or more.

  FIG. 17B is a diagram illustrating a case where the reception function of the vehicle D in the vehicle group including the vehicles A to G is stopped but the transmission function is effective. The vehicle D cannot receive communications from other vehicles because the reception function is stopped, and transmits no ACK for other vehicles in the MR packet (or HB packet). Since vehicles other than the vehicle D can receive communications from each vehicle in the vehicle group, the presence of ACK is stored for each vehicle and an MR packet or an HB packet is transmitted. In this way, a vehicle group packet with no ACK is received from vehicles D for vehicles in a vehicle group within a predetermined ratio or more (may be all vehicles), and a vehicle group packet with ACK is received from other vehicles. If it is, it can be determined that the reception function of the vehicle D has stopped. In addition, this determination is not determined in only one cycle, but when the vehicle D continuously transmits a vehicle group packet without ACK for each vehicle for a predetermined cycle or more, it is determined that the reception function of the vehicle D is stopped. It is preferable.

  FIG. 18 is a diagram illustrating control when the communication function of the preceding vehicle is stopped. When the communication function of vehicle D (both transmission function and reception function) stops, vehicle E transitions to a communication leader because the communication function of the preceding vehicle is stopped when the transmission timing arrives (S2806 YES). (S2810), a new vehicle group is generated with the vehicles F and G behind the host vehicle as communication members and registered as belonging vehicle group information (S2812). A vehicle group ID and a cycle that do not overlap with the external vehicle group are selected (S2814), the original vehicle group is registered in the exclusion list (S2816), and an HB packet is created and broadcast (S2818). Vehicles E, F, and G are stored in the vehicle group list of the HB packet.

  In the vehicles F and G that have received the HB packet transmitted from the vehicle E, the vehicle group ID of the HB packet is different from the vehicle group ID to which the vehicle belongs, but the vehicle group ID of the HB packet is in the vehicle group list of the HB packet. It can be seen that the vehicle ID exists. Therefore, since it can be recognized that the vehicle is a member of a different vehicle group than before, the belonging vehicle group information is edited in accordance with the received HB packet (S2704-S2706-S2708-S2710). Further, in order to avoid the vibration of the state due to the information from the original vehicle group, the original vehicle group is added to the exclusion list (S2912).

  In addition, the vehicle A (the communication leader of the original vehicle group) that has received the HB packet transmitted from the vehicle E receives the HB packet from another vehicle group (S2404-NO, S2406-YES), and It can be seen that the vehicle registered as the communication member in the vehicle group information of the vehicle is the transmission source (YES in S2412). Since the vehicle H as the transmission source of the received HB packet is the third and subsequent vehicles in the original vehicle group (S2416-NO), the vehicle E, the vehicles F and G behind it, and the vehicle D with the communication function stopped are included in the vehicle group. And the belonging vehicle group information is updated so that only the vehicles A, B, and C are included in the vehicle group list (S2420). In either case, a new vehicle group is added to the exclusion list so as not to cause vibration of the state with the separated vehicle group (S2414).

  The vehicles B and C that have received the HB packet including the vehicles A to C in the vehicle group list from the communication reader A recognize that the vehicle constituting the vehicle group has changed, and update the vehicle group information. .

  Here, the vehicle E cannot receive communications from surrounding vehicles because the reception function is stopped. Therefore, it can be estimated that the reception function of the vehicle E is stopped. Therefore, it is preferable that the vehicle E transitions from the vehicle group member state to the following traveling state without receiving a packet from another vehicle. If the reception function of the communication member stops (S2808-YES), the communication member transitions to the vehicle group preparation state (S2820) and edits the state information. Further, the original vehicle group is added to the exclusion list (S2822). As a result, the vehicle whose reception function has ceased can release the member by itself.

  Thus, even when the communication function is stopped in any vehicle in the vehicle group, the vehicle group is separated at that position to generate the front vehicle group and the rear vehicle group, and the vehicle group cooperative traveling can be performed. .

[9] Movement out of communicable range When the vehicle in the vehicle group moves out of the communicable range, the vehicle group is maintained between communicable vehicles. 19A and 19B, when a vehicle group is formed by five vehicles A to E, the distance between the vehicles A and B is increased, and communication between the vehicles A and B is performed. It is a figure which shows the case where it becomes impossible. Since vehicle B cannot receive communication from the preceding vehicle, the preceding vehicle cannot be specified (YES in S2804-). Accordingly, as shown in FIG. 14 (B), the vehicle B transitions to the communication leader, and forms a new vehicle group in which a vehicle located behind the own vehicle in the vehicle group is a communication member. Since the subsequent processing is the same as the processing described in [7] above, details are omitted.

  19 (A) and 19 (B) explain the case where the inter-vehicle distance is increased between the communication leader (first vehicle) and the second vehicle, the inter-vehicle distance is increased between arbitrary vehicles in the vehicle group. In this case, there is no substitute for a vehicle that can no longer identify the preceding vehicle transitions to the communication leader.

[10] Generation of radio wave interference When radio wave interference occurs, control is performed to recover communication quality by reducing the number of vehicles that perform vehicle group coordinated traveling and reducing the amount of communication.

  20A and 20B are diagrams illustrating a case where radio wave interference occurs in a vehicle group composed of seven vehicles A to G. FIG. When radio wave interference occurs, many vehicles in the vehicle group cannot receive radio waves. Therefore, the communication reader simultaneously receives MR packets containing many ACKs in the vehicle group list. In this way, the communication reader determines that a reception failure due to radio wave interference has occurred when communication members in the vehicle group cannot communicate with other vehicles as a whole.

  When the communication reader detects simultaneous frequent interruptions, the last vehicle is deleted from the belonging vehicle group information (S2606 to S2610). In this example, the last vehicle G in the vehicle group is excluded from the communication members and is registered as a vehicle outside the vehicle group. Then, the communication reader generates an HB packet including a new vehicle group list and performs broadcast communication (S2612).

  The vehicle G that has received the HB packet is an HB packet from the vehicle group to which the vehicle belongs, but the vehicle ID is not included in the HB packet, so the vehicle is excluded from the vehicle group. It is detected that the vehicle group has been prepared and transitions to the vehicle group preparation state (S2704-S2714-S2724-S2732).

  The vehicles B to F, which are communication members, can recognize that the vehicle G is excluded from the vehicle group by receiving the HB packet from the vehicle A, and update the state information.

  In this way, since the vehicle G and the vehicles A to F are separate vehicle groups, the vehicles F and G follow up by communication ACC, and the inter-vehicle distance is increased, so that radio wave interference is reduced. If the radio interference is not improved even if the vehicle G is excluded from the vehicle group, the radio interference is finally reduced by excluding the next rearmost vehicle.

  As described above, according to the present embodiment, it is possible to improve communication quality, that is, to suppress communication interruption by reducing the amount of communication in the vehicle group. In addition, even when communication interruption occurs, the range of significant influence can be limited to the vehicle group. Further, by separating the vehicle group when communication interruption occurs, it is possible to have a serious influence and limit the range within the vehicle group where communication interruption has occurred.

  Although the present invention has been described above with reference to exemplary embodiments, the present invention should not be construed as being limited to the embodiments described above. For example, in the embodiment, the case where the communication leader is the head of the vehicle group is described as an example, but the communication leader may be other than the head. Further, regardless of whether the communication leader is the head or other than the head, the vehicle positioned in front of the vehicle group may join the vehicle group. The case where the vehicle ahead is merged can be dealt with by the same processing as the case where the vehicle behind is merged. Further, when the communication leader changes in the vehicle group, the new communication leader may notify that the own vehicle has become the communication leader by the HB packet.

  In the above embodiment, the case where the communication reader and the control reader are the same vehicle is described as an example. However, the communication reader and the control reader are not necessarily the same vehicle. For example, a mode in which the communication leader is a vehicle near the center (a vehicle other than the leading vehicle) and the control leader is the leading vehicle is conceivable. The communication leader maintains and manages the vehicle group in the same manner as described above, and the control leader controls the platooning of the vehicle group. In this case, the control leader broadcast-transmits the travel control information including the target control value, and the communication reader that has received the broadcast transmits the travel control information to the vehicle group members again, thereby controlling the travel of each vehicle in the vehicle group. Communicate information. Thus, when the communication leader and the control leader are separate vehicles, the influence of dissolution such as member detachment is reduced and the robustness is improved. There is also an advantage that the range of the vehicle group is expanded by the transfer of the traveling control information by the communication reader.

701 Vehicle travel control ECU
702 Control unit 703 Storage unit 704 Timer 705 Inter-vehicle communication device 706 Communication unit 707 GPS device 708 Millimeter wave radar 709 Engine ECU
710 Brake ECU
711 Steering ECU

Claims (25)

A platooning communication system that forms a vehicle group from a plurality of vehicles capable of bidirectional communication, with one vehicle as a leader and other vehicles as members, and performs platooning using communication between vehicles in the vehicle group Vehicle group management method by
A reader periodically sending information;
Each member returning a response to the information sent from the reader;
Including
The information transmitted from the leader includes reception information indicating whether communication from each member in the previous cycle has been received,
Information transmitted from each member includes reception information indicating whether communication from the leader in the current cycle and communication from other members in the previous cycle have been received,
Each vehicle performs delivery confirmation based on reception information included in information transmitted from other vehicles,
A vehicle group management method, comprising forming and maintaining a vehicle group with vehicles whose communication bidirectionality has been confirmed by the delivery confirmation. The information that each vehicle periodically transmits includes the position of the vehicle, the identifier of the vehicle that constitutes the vehicle group, and the reception response for each vehicle that constitutes the vehicle group,
The vehicle group management according to claim 1, wherein each vehicle autonomously performs traveling control based on information transmitted from another vehicle and information acquired by a sensor included in the own vehicle. Method. The vehicle group management method according to claim 2, wherein the information periodically transmitted by the vehicles constituting the vehicle group further includes a traveling order of the vehicles constituting the vehicle group within the vehicle group. 4. The vehicle according to claim 3, wherein identifiers of vehicles constituting the vehicle group are listed in the information periodically transmitted by the vehicles constituting the vehicle group according to a traveling order in the vehicle group. Group management method. The vehicle located at the head of the vehicle group performs traveling control to follow the vehicle ahead of the vehicle group,
The vehicle group management method according to any one of claims 1 to 4, wherein an inter-vehicle distance between a leading vehicle of the vehicle group and a vehicle ahead of the vehicle group is longer than an inter-vehicle distance within the vehicle group. The information transmitted by each vehicle includes at least the position of the vehicle,
Each vehicle has distance measuring means capable of measuring the position of the vehicle ahead,
It is determined whether the vehicle is continuous depending on whether the position included in the information transmitted from the vehicle matches the position of the preceding vehicle measured by the distance measuring means,
6. The vehicle group management method according to claim 1, wherein bidirectionality of communication is confirmed by the delivery confirmation and a vehicle group is formed and maintained by continuous vehicles. The vehicle group management method according to any one of claims 1 to 6, wherein the leader is a leading vehicle in the vehicle group. The vehicle group management method according to claim 6 or 7, wherein an upper limit is set for the number of vehicles constituting the vehicle group. When the bidirectionality and continuity of communication are confirmed between two vehicles that do not constitute a vehicle group, the vehicle group is formed by the two vehicles. The vehicle group management method according to claim 8. The leader is the leading vehicle in the vehicle group,
The vehicle group management method according to claim 9, wherein, of the two vehicles, a front vehicle is a leader and a rear vehicle is a member. Bidirectional communication is confirmed between the plurality of first vehicles constituting the vehicle group and the second vehicle not constituting the vehicle group, and
When it is determined that one of the first vehicles and the second vehicle are continuous,
The vehicle group management method according to any one of claims 6 to 10, wherein the second vehicle is joined to the vehicle group. The leader is the leading vehicle in the vehicle group,
12. The second vehicle is joined to the vehicle group when it is determined that the last vehicle in the vehicle group and the second vehicle are continuous. Vehicle group management method. With respect to the plurality of first vehicles constituting the first vehicle group and the plurality of second vehicles constituting the second vehicle group, the bidirectionality of communication is confirmed between all the vehicles, and , When it is determined that any one of the first vehicles and any one of the second vehicles are continuous,
The vehicle group management method according to any one of claims 6 to 12, wherein the first vehicle group and the second vehicle group are merged. The leader is the leading vehicle in the vehicle group,
When it is determined that the last vehicle in the first vehicle group and the first vehicle in the second vehicle are continuous, all the vehicles in the second vehicle group are displayed in the first vehicle group. The vehicle group management method according to claim 13, wherein the vehicle groups are merged as members of the vehicle group. In any vehicle in the vehicle group, the position of the preceding vehicle measured by the distance measuring unit of the vehicle is equal to the position of the vehicle two vehicles before the vehicle based on information transmitted from the other vehicle. If it can be determined that the vehicle located in front of the vehicle has departed from the vehicle group, the detached vehicle is excluded from the vehicle group. Vehicle group management method. When any vehicle in the vehicle group cancels the platooning, it is separated into two vehicle groups, a vehicle group consisting of vehicles ahead of the vehicle and a vehicle group consisting of vehicles behind the vehicle. The vehicle group management method according to any one of claims 6 to 15. When a vehicle that cannot communicate with another vehicle appears in the vehicle group, the vehicle group is composed of a vehicle ahead of the vehicle and the vehicle group composed of a vehicle behind the vehicle. It isolate | separates. The vehicle group management method in any one of Claims 6-16 characterized by the above-mentioned. The case where a vehicle that cannot communicate with other vehicles appears in the vehicle group is when a vehicle that does not have a communication function is interrupted in the vehicle group,
In any vehicle in the vehicle group, the position of the front vehicle measured by the distance measuring means of the vehicle does not match the position of any vehicle in the vehicle group obtained from information transmitted from another vehicle The vehicle group management method according to claim 17, further comprising: determining that a vehicle having no communication function has interrupted in front of the host vehicle. The case where a vehicle that cannot communicate with other vehicles appears in the vehicle group is when the communication function of the vehicle in the vehicle group stops,
The vehicle group in the vehicle group according to claim 17, wherein the vehicle in the vehicle group determines stop of a communication function of the vehicle in the vehicle group based on reception information included in information transmitted from another vehicle. Management method. The vehicle group management method according to any one of claims 6 to 19, wherein when simultaneous communication interruption occurs in the vehicle group, at least one member in the vehicle group is excluded from the vehicle group. The leader is the leading vehicle in the vehicle group,
21. The vehicle group management method according to claim 20, wherein when the simultaneous communication interruption occurs in the vehicle group, the last vehicle in the vehicle group is excluded from the vehicle group. The information transmitted by each vehicle includes the identifiers of the vehicles that make up the vehicle group,
The member resets the identifier of the own vehicle when a plurality of identifiers identical to the identifier of the own vehicle are included in the information transmitted from the reader. Vehicle group management method described in 1. The information transmitted by each vehicle includes the identifiers of the vehicles that make up the vehicle group in a format with a reduced number of bits.
The member resets the identifier of the own vehicle when the information transmitted from the reader includes the same identifier as the identifier of the format in which the number of bits of the own vehicle is shortened. The vehicle group management method according to claim 22. It is a platooning communication system composed of a plurality of vehicles each equipped with an in-vehicle wireless terminal,
A vehicle group is formed with one vehicle among a plurality of vehicles as a leader and other vehicles as members,
The reader sends information regularly,
Each member returns a response to the information sent from the reader,
The information transmitted from the leader includes reception information indicating whether communication from each member in the previous cycle has been received,
Information transmitted from each member includes reception information indicating whether communication from the leader in the current cycle and communication from other members in the previous cycle have been received,
Each vehicle performs delivery confirmation based on reception information included in information transmitted from other vehicles,
A platooning communication system, characterized in that a vehicle group is formed and maintained by vehicles whose communication bidirectionality has been confirmed by the delivery confirmation. A convoy travel communication system of a vehicle group, each consisting of a plurality of vehicles equipped with in-vehicle wireless terminals,
One vehicle in the vehicle group as a control leader for controlling platooning,
One vehicle out of the vehicles other than the control leader in the vehicle group is a communication reader that transfers control information transmitted from the control reader to other vehicles in the vehicle group.
A row running communication system characterized by the above.

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