JP5708367B2 - Convoy travel control device and convoy travel control method - Google Patents

Description

  The present invention relates to a convoy travel control device and a convoy travel control method.

  Systems for running multiple vehicles in a row are being researched and developed. By exchanging vehicle control information using inter-vehicle communication or the like, the inter-vehicle distance from the preceding vehicle can be kept short. Convoy travel is expected to improve traffic flow and improve fuel economy due to reduced air resistance.

  By the way, the sag part and the tunnel are known as places where traffic jams occur. It is known that when a large vehicle group having a high density arrives at such a traffic jam location, the traffic jam gets worse (Non-Patent Document 1).

  In order to reduce traffic jams, it is desirable to detect the presence of traffic jams before the vehicle group reaches the traffic jams and reduce the size of the vehicle group or increase the inter-vehicle distance in advance.

JP 2010-244121 A

Hiroshi Makino and three others, "Reduction of sag traffic conditions by optimizing lane utilization", Civil Engineering Technical Information 47 (10), 38-43, 2005-10

  An object of the present invention is to provide a technology for detecting a traffic jam before arriving at a traffic jam location, and further to provide a technology for performing platooning control so as not to deteriorate the traffic jam before arriving at a traffic jam. is there.

A convoy travel control device according to the present invention is a convoy travel control device that performs convoy travel control based on a radio signal transmitted from the vicinity of an area within a predetermined distance among received radio signals, A communication status detecting means for detecting a communication status in a distant area that is farther than the predetermined distance from the received radio signal, and a communication status in the vicinity based on a change in the communication status in the remote location. A convoy control means for performing any of the control of canceling the convoy travel, reducing the number of vehicle groups, or increasing the inter-vehicle distance when it is predicted that the vehicle is congested;

  In a platooning system using inter-vehicle communication, a high packet arrival rate is required to ensure control. For example, in order to satisfy the communication requirement of a packet arrival rate of 95%, platooning control is performed according to a packet transmitted from a short distance (about 100 meters). In this specification, communication used for platooning control is referred to as “neighbor communication”, and a range in which proximity communication is performed is referred to as “vicinity”.

  Conversely, even if communication from a distant place can be received (demodulated), it is not used for platooning control. In the present specification, a region farther than the “near” is referred to as “far”.

In the present invention, a change in the communication status in the far field is grasped based on a radio signal from a far field, that is, a radio signal that is not directly used for platooning. By using the change in the communication status in the far distance, it is possible to predict the change in the near field communication before the near field communication used for the platooning actually changes. The case where the near field communication is predicted to be congested is a case where a traffic jam has occurred in the front. Therefore, before the platoon arrives in the traffic jam, it is possible to suppress the deterioration of the traffic jam by performing in advance control such as canceling the platooning, reducing the number of vehicles, and increasing the inter-vehicle distance.

  The communication status in the far field can be detected based on the number of received packets and the location information of the transmission source included in the received packets. That is, it is possible to grasp from which position the packet is transmitted from the position information included in the packet. Then, based on the number of packets received from each position, it is possible to grasp the communication status in the distance.

  Alternatively, the communication status in the distance can be detected based on the noise level in the received radio signal. When there is a traffic jam in the distance, the noise level is high, and the noise level further increases as it approaches. Therefore, it is possible to grasp the communication state in the distance based on the noise level.

  From the number of received packets or noise level (hereinafter referred to as the number of received packets) received from a distant place, it is possible to determine the time or distance until the neighborhood communication changes and how much congestion the neighborhood communication will have. It is preferable to do. For this purpose, the number of received packets and the like may be obtained by performing actual measurement and simulation under various conditions regarding the number of distant vehicles. Then, the correspondence between the number of received packets, the time until the neighborhood communication changes, the distance, and the neighborhood communication with the congestion degree may be stored in the form of a lookup table. The convoy control means can acquire the time until the proximity communication changes and the degree of congestion from the number of received packets and the look-up table, and convoy travel control is possible based on these information.

  If the control method of platooning can be determined directly from the time until proximity communication changes and the degree of congestion, the number of packets or noise level received from a distance and the control method of platooning are stored in the lookup table. Can be associated. In this case, by referring to the lookup table, it can be predicted that the communication status in the vicinity will be congested, and what kind of row running control should be performed at the same time.

  As another method, instead of using a lookup table, it may be possible to obtain in advance a mathematical expression that represents the relationship between the number of received packets and the like, the time and distance until the neighborhood communication changes, and the degree of congestion of the neighborhood communication. Then, based on this relational expression, the time and distance until the neighborhood communication changes from the number of received packets from a distant place and the congestion degree of the neighborhood communication may be obtained. The convoy travel control means can determine the convoy travel control method based on the time and distance until the proximity communication changes in this way and the congestion degree of the proximity communication.

  As yet another method, conditions for executing formation control may be determined in advance as conditional expressions relating to the number of received packets and the rate of change thereof. The formation control may be executed when the number of received packets and the rate of change thereof satisfy this conditional expression.

  The present invention can be regarded as a row running control device having at least a part of the above means. Moreover, this invention can also be grasped | ascertained as a convoy travel system comprised from the several vehicle which has these convoy travel control apparatuses. The present invention can also be understood as a platooning control method for executing the above-described processing, or a program for realizing this method. Each of the above means and processes can be combined with each other as much as possible to constitute the present invention.

  According to the present invention, it is possible to detect a traffic jam before arriving at a traffic jam location, and to perform a row running control that does not worsen the traffic jam.

It is a figure which shows the functional block of the row control apparatus mounted in the vehicle which comprises a row running system. It is a figure which shows the packet format of vehicle-to-vehicle communication. It is a figure which shows the relationship between the distance from traffic jam, and a packet arrival rate. It is a figure which shows the relationship between the distance from traffic jam, and the number of packet reception. It is a figure which shows the example of the look-up table which correlates the content of the number of reception packets, its change rate, and convoy travel control. It is a flowchart which shows the flow of row | line | column running control processing in 1st Embodiment.

  Exemplary embodiments of the present invention will be described in detail below with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic diagram illustrating a functional configuration of a row running control device included in each vehicle in the row running control system according to the present embodiment. The convoy travel control device 1 includes a millimeter wave radar 2, a GPS device 3, an inter-vehicle communication device 4, and a convoy travel control ECU 5. The convoy travel control ECU 5 is a computer composed of a CPU, a ROM, a RAM, and the like, and realizes functions described below when the CPU executes a program.

  The convoy travel control ECU 5 acquires the distance from the millimeter wave radar 2 to the surrounding vehicle and the current position from the GPS device 3, and acquires various information from the surrounding vehicle by the inter-vehicle communication device 4. In inter-vehicle communication, each vehicle exchanges information such as the current position of the host vehicle, target acceleration, target speed, current acceleration, current speed, and order in the vehicle group. The inter-vehicle communication device 4 transmits the vehicle information at a frequency of once every 100 milliseconds, for example.

  Although detailed processing of inter-vehicle communication for maintaining and managing platooning is omitted, for example, a management leader in the vehicle group periodically sends a message, and other vehicles send messages in response to this. The form to do is employable.

  FIG. 2 shows an example of a packet format used for inter-vehicle communication. As shown in the figure, the packet includes a transmission source ID 201, a destination ID 202, position information 203 of the transmission source vehicle, and other convoy control information 204. Although not shown, header information and footer information according to various protocols are added to these payloads.

  The convoy travel control ECU 5 determines the target acceleration, target speed, target position, etc. of the own vehicle based on information obtained from the millimeter wave radar 2, the GPS device 3, the inter-vehicle communication device 4, etc., and implements it. In addition, the throttle 6, brake 7, steering 8 and the like are controlled. Since the process of determining the control amount of the vehicle based on various input information may be performed in the same manner as the conventional row running control, detailed description thereof is omitted.

The convoy travel control ECU 5 according to the present embodiment performs control such as canceling convoy travel based on a change in communication status. A group of vehicles running in a platoon is running densely with a narrow inter-vehicle distance. In the conventional platooning control, when such a group of vehicles approaches a traffic jam location, the platooning is canceled or the inter-vehicle distance is increased. Then, the traffic congestion gets worse. Therefore, in the convoy travel control ECU 5 according to this embodiment, the convoy travel control is canceled, the inter-vehicle distance is increased, and the number of vehicle groups is increased sufficiently before the vehicle group in the convoy travel reaches the traffic jam location. By performing control such as reduction in advance, congestion deterioration is suppressed.

  In the vehicle-to-vehicle communication used in the platooning control, high communication quality is required. For example, communication requirements such as a packet arrival rate of 95% may be imposed. In order to satisfy this requirement, the inter-vehicle communication used for platooning control is configured to refer only to packets transmitted from within a predetermined distance (for example, 100 meters).

  Here, a change in the communication status when the vehicle group approaches a traffic jam location will be described. FIG. 3 is a graph showing the packet arrival rate in the approaching vehicle group when the platoon approaches a traffic jam of 1500 meters. It is assumed that there are about 130 communication vehicles in the traffic jam and about 40 communication vehicles in the vehicle group. In this graph, the horizontal axis is the distance from the tail end of the traffic jam, and the vertical axis is the distance to the communication partner. For example, it can be seen that, within a distance of 500 meters behind the end of the traffic jam, communication with a communication partner located about 50 meters to about 200 meters away can be performed with a packet arrival rate of 95% to 99%.

  As can be seen from FIG. 3, it can be seen that the communication quality deteriorates as the traffic congestion is approached. That is, when the communication distance is the same, the packet arrival rate deteriorates as the traffic congestion is approached. Although not clearly shown in FIG. 3, the packet arrival rate is deteriorated with respect to approaching a traffic jam even in a region where the packet arrival rate is less than 90% (a portion not shaded).

  FIG. 3 shows the packet arrival rate. FIG. 4 is a graph showing the number of packets received per unit time for each communication distance in the same situation. A solid line represents the number of received packets received from a vehicle 100 meters away, and a dotted line represents the number of received packets received from a vehicle 500 meters away. As can be seen from the figure, the number of packets received from a vehicle 100 meters away increases rapidly after reaching the end of the traffic jam (area A). On the other hand, the number of packets received from a vehicle 500 meters away gradually rises from a position away from the tail of the traffic jam (area B). Therefore, by monitoring the number of packets from a vehicle 500 meters away, it is possible to detect the presence of traffic before reaching the traffic.

  Note that the values of 100 meters and 500 meters used in the above description are examples, and can be appropriately changed according to the requirements of the system. More generally, when the area within the distance of inter-vehicle communication used for platooning is defined as "near" and the area farther than that is defined as "far", the number of packets received from far away is monitored. Thus, the presence of the traffic jam can be detected before approaching the vicinity of the traffic jam.

  As described above, the convoy travel control ECU 5 includes the distant communication state determination unit 51, the lookup table 52, and the convoy travel control unit 53 in order to perform the convoy control according to the number of received packets from a distant place.

  The far communication state determination unit 51 counts the number of packets received from a distant place. Here, a packet received from a distance may be defined as a packet received from a position 450 to 550 meters away, or may be defined as a packet received from a range beyond 500 meters. Since the position of the packet transmission source is included in the received packet as the packet position information 203, the far communication state determination unit 51 compares the position information of the own vehicle obtained from the GPS device 3 to determine the communication distance of the packet. Can be calculated.

The look-up table 52 stores what row control is performed in correspondence with the number of packets received from a distance and the rate of change. FIG. 5 shows an example of the lookup table 52. In this example, when the number of received packets is large and the rate of increase is high (area 1), the platoon (vehicle group) is eliminated. Further, when the number of received packets and the rate of change thereof are medium (area 2), control is performed to increase the inter-vehicle distance of the platooning or reduce the vehicle group size. In other words, if the length of the convoy is within the allowable range, the distance between the vehicles will only be increased even if the required inter-vehicle distance is exceeded. If the length of the convoy exceeds the allowable range, the number of vehicles included in the convoy will be reduced. To do. In addition, when the number of received packets and the rate of change thereof are small (area 3), special row running control is not performed.

  Such a look-up table 52 can be created by conducting experiments or simulation calculations for approaching a convoy with various sizes of traffic jams. That is, for each traffic jam size, the number of received packets and the rate of change thereof are measured as they approach. Since it is possible to determine what row running control should be performed according to the size of the traffic jam, it is possible to create a table that associates the number of received packets and the rate of change thereof with a control method.

  FIG. 6 is a flowchart showing a method for controlling the row running in the present embodiment. First, the inter-vehicle communication device 4 receives and demodulates packets from other vehicles (step S601). The far-field communication status determination unit 51 determines whether the received packet is transmitted from a distance (predetermined area) based on a comparison between the position information included in the received packet and the position information of the host vehicle. The number of received packets is counted (step S602). The far-field communication status determination unit 51 calculates the number of received packets and the rate of change at every predetermined time and notifies the platooning control unit 53 (step S603). The convoy travel control unit 53 determines the convoy control method for the notified number of received packets and the rate of change thereof with reference to the lookup table 52 (step S604), and implements the control contents (step S605).

  According to this embodiment, by monitoring packets from a distance that are not used for normal platooning control, it becomes possible to quickly grasp the state change of proximity communication (that is, approach to a traffic jam). Furthermore, it is possible to perform control such as appropriately adjusting the size of the platoon or releasing the platoon before the neighborhood communication changes. As a result, it is possible to avoid a situation in which further deterioration of the traffic jam occurs when the platoon approaches the traffic jam location.

  In the above description, the control of the lookup table shown in FIG. 5 is an example, and it is not always necessary to perform a plurality of different controls depending on the situation. That is, the definition may be such that only the control of canceling the formation is performed when the communication condition in the distance satisfies a specific condition. Further, instead of canceling the platoon, the control may be only the reduction of the vehicle group size or the increase of the inter-vehicle distance.

  Further, in the above description, only the number of received packets received from a specific range is considered as the communication situation in the distance. However, it is also possible to set a plurality of areas far and determine the platooning control based on the number of packets received from each area and changes thereof. For example, the number of packet receptions received from a vehicle 1000 to 300 meters away and the number of packet receptions received from a vehicle 300 to 500 meters away are measured, and platooning control is performed based on these packet receptions and the rate of change thereof. Can be considered.

  In the above description, the convoy control is determined based on the number of received packets and the change (first derivative), but it is also preferable to determine the convoy travel control using a secondary or higher derivative value. .

(Second Embodiment)
In the first embodiment, the lookup table 52 defines the relationship between the number of received packets from a distant location and the rate of change thereof and the formation control method. In the present embodiment, the number of received packets from a distance and the change thereof are associated with the lookup table, the distance to reach the traffic jam, and the degree of traffic jam. The lookup table can be created by actual measurement or simulation calculation, as described above.

  In this embodiment, the convoy travel control unit 53 can acquire the distance to reach the traffic jam and the degree of the traffic jam based on the number of packets received from a distant location, the rate of change thereof, and the lookup table. Then, based on the obtained degree of traffic jam and the distance to the traffic jam, it is determined what row running control is to be performed.

  Specifically, as in the first embodiment, when the vehicle density reaches a traffic jam with high vehicle density, the platooning is canceled, and when the vehicle density reaches a medium traffic jam, the inter-vehicle distance is increased. The size of the group can be reduced. In this embodiment, since the distance to reach the traffic jam (and the time to reach the vehicle by considering the travel speed) is known, the timing for starting the row running control is delayed from the detection of the traffic jam. It is also possible.

(Third embodiment)
In the present embodiment, the content of the convoy travel control is determined using a calculation formula without using a lookup table.

  As an example of such a method, it is conceivable to define in advance a conditional expression for the number of received packets from a distant place and the rate of change thereof in order to start platooning control. For example, the conditional expression is such that when the number of received packets is equal to or greater than a predetermined number and the rate of change is equal to or greater than a threshold, the formation running is canceled. Even in this way, the platooning can be appropriately adjusted in advance before reaching the traffic jam based on the number of received packets from a distance.

  As another example, it may be possible to calculate in advance a relational expression for calculating the distance to reach a traffic jam and the congestion degree of the traffic jam from the number of received packets and the rate of change thereof. If necessary for the calculation, it is preferable to use not only the rate of change (first derivative) of the received packet but also the rate of change (secondary derivative). If the distance to the traffic jam and the congestion level of the traffic jam are known, the content of the platooning control can be determined.

(Fourth embodiment)
In the first to third embodiments, the platooning control is determined using the number of received packets from a distance. In the present embodiment, the magnitude of the noise level is used in order to grasp the communication state at a distance.

  In the present embodiment, the far communication state determination unit 51 acquires the magnitude of the noise level from the inter-vehicle communication device 4. The look-up table 52 stores the magnitude of the noise level and the rate of change thereof in association with the platoon control method. The lookup table can be created by performing an experiment or simulation calculation for measuring the noise level while approaching traffic jams of various sizes.

  The convoy travel control unit 53 performs convoy travel control determined from the magnitude and change of the noise level and the look-up table 52.

  Even with such a method, before reaching the traffic jam, it is possible to grasp the existence of the traffic jam and make appropriate adjustments to the squadron, such as releasing the platoon, increasing the inter-vehicle distance, and reducing the number of vehicles. It becomes possible. Moreover, it can suppress further deteriorating the traffic jam.

  As in the second and third embodiments, the noise level, the distance to the traffic jam, and the size of the traffic jam may be defined in the lookup table, or a calculation formula may be used instead of the lookup table. . The same effect can be obtained by such a method.

DESCRIPTION OF SYMBOLS 1 Convoy travel apparatus 2 Millimeter wave radar 3 GPS apparatus 4 Inter-vehicle communication apparatus 5 Convoy travel control ECU
51 Remote communication status determination unit 52 Look-up table 53 Convoy travel control unit 6 Throttle 7 Brake 8 Steering

Claims (10)

A convoy travel control device that performs convoy travel control based on a radio signal transmitted from the vicinity of an area within a predetermined distance among received radio signals,
Receiving means for receiving a radio signal;
A communication status detection means for detecting a communication status in a distant area that is farther than the predetermined distance from the received radio signal;
When it is predicted that the communication situation in the vicinity will be congested based on the change in the communication situation in the distance, control of either canceling the platooning, reducing the number of vehicle groups, or increasing the inter-vehicle distance is performed. Formation control means,
A convoy travel control device comprising: The communication status detection means detects the communication status in a remote place based on the number of received packets and the location information of the transmission source included in the received packets.
The row running control device according to claim 1. The communication status detection means detects a communication status in a distance based on the noise level in the received radio signal.
The row running control device according to claim 1. The platoon control means determines a platoon control method in a case where it is predicted that the communication situation in the vicinity is congested using a table in which a change in communication condition in the distance and a control method of platoon travel are associated with each other.
The convoy travel control apparatus according to any one of claims 1 to 3. The platoon control means stores a platoon control method and a conditional expression to be satisfied by a noise level in a received radio signal or the number of packets received from a distance to implement the platoon control method. Determine the convoy control method based on the remote communication status detected by the
The convoy travel control apparatus according to any one of claims 1 to 3. A platoon that has a receiving means, a communication status detecting means, and a platoon control means, and that performs platooning control based on a wireless signal transmitted from the vicinity that is an area within a predetermined distance among the received wireless signals.
A row running control method performed by a running control device,
A receiving step in which the receiving means receives a radio signal;
A communication status detecting step in which the communication status detecting means detects a communication status in a distant area that is farther than the predetermined distance from the received radio signal;
If the convoy control means is predicted that the communication situation in the vicinity is congested based on a change in the communication situation in the distance, cancel the convoy travel, reduce the number of vehicle groups, or widen the inter-vehicle distance, A column control step for performing any of the controls,
Convoy travel control method. In the communication status detection step, based on the number of received packets and the location information of the transmission source included in the received packets, the communication status in the distance is detected.
The row running control method according to claim 6. In the communication status detection step, based on the noise level in the received radio signal, the communication status in the distance is detected.
The row running control method according to claim 6. In the formation control step, by using a table in which a change in communication status in the distance and a control method of formation running are associated, a formation control method is determined when the communication status in the vicinity is predicted to be congested.
The convoy travel control method according to any one of claims 6 to 8. The convoy travel control device stores in advance a convoy control method and a conditional expression to be satisfied by the noise level in the received radio signal or the number of packets received from a distance to implement the convoy control method,
In the formation control step, a formation control method is determined based on the communication status in the remote location detected in the communication status detection step and the conditional expression.
The convoy travel control method according to any one of claims 6 to 8.

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