U.S. patent application number 13/387284 was filed with the patent office on 2012-05-17 for vehicle control device, vehicle control method, and vehicle control system.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Masayoshi Hoshino, Kazunori Kagawa.
Application Number | 20120123660 13/387284 |
Document ID | / |
Family ID | 43528879 |
Filed Date | 2012-05-17 |
United States Patent
Application |
20120123660 |
Kind Code |
A1 |
Kagawa; Kazunori ; et
al. |
May 17, 2012 |
VEHICLE CONTROL DEVICE, VEHICLE CONTROL METHOD, AND VEHICLE CONTROL
SYSTEM
Abstract
The amount of traffic on the road is greatly affected by both an
inter-vehicle distance and a vehicle speed. When the amount of
traffic increases and is more than a threshold value, an ECU and an
ACC control the inter-vehicle distance and the vehicle speed such
that the amount of traffic is a predetermined value equal to or
more than the threshold value. In this way, it is possible to
effectively suppress traffic congestion.
Inventors: |
Kagawa; Kazunori; (Aichi,
JP) ; Hoshino; Masayoshi; (Aichi, JP) |
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
|
Family ID: |
43528879 |
Appl. No.: |
13/387284 |
Filed: |
July 28, 2009 |
PCT Filed: |
July 28, 2009 |
PCT NO: |
PCT/JP2009/063426 |
371 Date: |
January 26, 2012 |
Current U.S.
Class: |
701/96 |
Current CPC
Class: |
G08G 1/167 20130101;
B60W 2754/30 20200201; G08G 1/00 20130101; G08G 1/163 20130101;
B60W 30/16 20130101; G08G 1/0133 20130101; B60W 2556/65 20200201;
G08G 1/22 20130101; G08G 1/0145 20130101; G08G 1/164 20130101; B60W
2556/50 20200201; G08G 1/0112 20130101; B60W 2754/10 20200201 |
Class at
Publication: |
701/96 |
International
Class: |
G08G 1/00 20060101
G08G001/00 |
Claims
1-15. (canceled)
16: A vehicle control device comprising: information acquiring unit
for acquiring information related to the amount of traffic on a
road on which a host vehicle travels; and traveling control unit
for, when the amount of traffic related to the information acquired
by the information acquiring unit is more than a first threshold
value, controlling an inter-vehicle distance between the host
vehicle and other vehicles traveling on the road and the speed of
the host vehicle such that the amount of traffic is equal to or
more than a second threshold value.
17: The vehicle control device according to claim 16, wherein the
traveling control unit changes the inter-vehicle distance and the
vehicle speed at which the amount of traffic is equal to or more
than the second threshold value, depending on the number of other
vehicles which can communicate with the host vehicle.
18: The vehicle control device according to claim 16, wherein the
information acquiring unit acquires information related to the
number of other vehicles which cannot communicate with the host
vehicle between the host vehicle and other vehicles which can
communicate with the host vehicle, and the traveling control unit
changes the inter-vehicle distance at which the amount of traffic
is equal to or more than the second threshold value, depending on
the number of other vehicles which cannot communicate with the host
vehicle between the host vehicle and other vehicles which can
communicate with the host vehicle related to the information
acquired by the information acquiring unit.
19: The vehicle control device according to claim 16, wherein the
traveling control unit changes the first threshold value, depending
on a region including the road.
20: The vehicle control device according to claim 17, wherein the
information acquiring unit acquires information related to the
amount of traffic in each lane of the road, and the traveling
control unit controls at least one of the inter-vehicle distance
and the vehicle speed on the basis of the amount of traffic in each
lane of the road related to the information acquired by the
information acquiring unit.
21: A vehicle control method comprising: a step of acquiring
information related to the amount of traffic on a road on which a
host vehicle travels; and a step of, when the amount of traffic
related to the acquired information is more than a first threshold
value, controlling an inter-vehicle distance between the host
vehicle and other vehicles traveling on the road and the speed of
the host vehicle such that the amount of traffic is equal to or
more than a second threshold value.
22: The vehicle control method according to claim 21, wherein, in
the step of controlling the inter-vehicle distance and the vehicle
speed such that the amount of traffic is equal to or more than the
second threshold value, the inter-vehicle distance and the vehicle
speed at which the amount of traffic is equal to or more than the
second threshold value are changed depending on the number of other
vehicles which can communicate with the host vehicle.
23: The vehicle control method according to claim 21, wherein, in
the step of acquiring the information related to the amount of
traffic on the road on which the host vehicle travels, information
related to the number of other vehicles which cannot communicate
with the host vehicle between the host vehicle and other vehicles
which can communicate with the host vehicle is acquired, and in the
step of controlling the inter-vehicle distance and the vehicle
speed such that the amount of traffic is equal to or more than the
second threshold value, the inter-vehicle distance at which the
amount of traffic is equal to or more than the second threshold
value is changed depending on the number of other vehicles which
cannot communicate with the host vehicle between the host vehicle
and other vehicles which can communicate with the host vehicle
related to the acquired information.
24: The vehicle control method according to claim 21, wherein, in
the step of controlling the inter-vehicle distance and the vehicle
speed such that the amount of traffic is equal to or more than the
second threshold value, the first threshold value is changed
depending on a region including the road.
25: The vehicle control method according to claim 22, wherein, in
the step of acquiring the information related to the amount of
traffic on the road on which the host vehicle travels, information
related to the amount of traffic in each lane of the road is
acquired, and in the step of controlling the inter-vehicle distance
and the vehicle speed such that the amount of traffic is equal to
or more than the second threshold value, at least one of the
inter-vehicle distance and the vehicle speed is controlled on the
basis of the amount of traffic in each lane of the road related to
the information acquired.
26: A vehicle control system comprising: information acquiring unit
for acquiring information related to the amount of traffic on a
road on which a plurality of vehicles travel; and traveling control
unit for, when the amount of traffic related to the information
acquired by the information acquiring unit is more than a first
threshold value, controlling an inter-vehicle distance between at
least two of the vehicles traveling on the road and the speed of at
least one of the vehicles such that the amount of traffic is equal
to or more than a second threshold value.
27: The vehicle control system according to claim 26, wherein the
traveling control unit changes the inter-vehicle distance and the
vehicle speed at which the amount of traffic is equal to or more
than the second threshold value, depending on the number of
vehicles which can communicate with each other.
28: The vehicle control system according to claim 26, wherein the
information acquiring unit acquires information related to the
number of vehicles which cannot communicate with each other between
the vehicles which can communicate with each other, and the
traveling control unit changes the inter-vehicle distance at which
the amount of traffic is equal to or more than the second threshold
value, depending on the number of vehicles which cannot communicate
with each other between the vehicles which can communicate with
each other related to the information acquired by the information
acquiring unit.
29: The vehicle control system according to claim 26, wherein the
traveling control unit changes the first threshold value, depending
on a region including the road.
30: The vehicle control system according to claim 27, wherein the
information acquiring unit acquires information related to the
amount of traffic in each lane of the road, and the traveling
control unit controls at least one of the inter-vehicle distance
and the vehicle speed on the basis of the amount of traffic in each
lane of the road related to the information acquired by the
information acquiring unit.
Description
TECHNICAL FIELD
[0001] The present invention relates to a vehicle control device, a
vehicle control method, and a vehicle control system and more
particularly, to a vehicle control device, a vehicle control
method, and a vehicle control system capable of improving the
amount of traffic on the road.
BACKGROUND ART
[0002] In recent years, there is an attempt to control the
traveling of each vehicle, thereby improving the amount of traffic
on the road and reducing traffic congestion. For example, Patent
Literature 1 discloses a vehicle-in-front following device which
detects a change in the gradient of the front side of the road and
changes the control mode from inter-vehicle distance control to
vehicle speed control when a change in the gradient is detected in
front of the road in the vicinity of, for example, a sag section
(position where the road is changed from a descent to an ascent).
In the vehicle-in-front following device disclosed in Patent
Literature 1, the control mode is changed from inter-vehicle
distance control to vehicle speed control in the vicinity of the
sag section, thereby suppressing a change in the vehicle speed
during vehicle-in-front following control. In particular, the
vehicle-in-front following device disclosed in Patent Literature 1
prevents a phenomenon in which a change in the speed of the vehicle
in front is amplified and propagated to the following vehicle even
though the gradient is changed in the sag section when a plurality
of vehicles travel in a line.
CITATION LIST
Patent Literature
[0003] [Patent Literature 1] Japanese Unexamined Patent Application
Publication No. 2002-137652
SUMMARY OF INVENTION
Technical Problem
[0004] However, in the above-mentioned technique, even when the
control mode is changed to vehicle speed control in the vicinity of
the sag section, deceleration propagation in which the deceleration
of the vehicle in front is propagated to the following vehicle is
not prevented. When the vehicles travel in a line, the deceleration
of the vehicle increases toward the rear side. In the
above-mentioned technique, when the control mode is changed to
vehicle speed control in front of the sag section, but the
deceleration propagation occurs, there is a concern that the
control mode will return to inter-vehicle distance control in order
to prevent the inter-vehicle distance from being too short.
Therefore, in the above-mentioned technique, the control mode is
changed from vehicle speed control to inter-vehicle distance
control at the time when the deceleration propagation occurs,
resulting in traffic congestion in which a plurality of vehicles
travel in a line at a low speed. As a result, it is difficult to
effectively suppress traffic congestion.
[0005] The invention has been made in view of the above-mentioned
problems and an object of the invention is to provide a vehicle
control device, a vehicle control method, and a vehicle control
system capable of effectively suppressing traffic congestion.
Solution to Problem
[0006] According to an aspect of the invention, there is a provided
a vehicle control device including: information acquiring means for
acquiring information related to the amount of traffic on a road on
which a host vehicle travels; and traveling control means for, when
the amount of traffic related to the information acquired by the
information acquiring means is more than a first threshold value,
controlling an inter-vehicle distance between the host vehicle and
other vehicles traveling on the road and the speed of the host
vehicle such that the amount of traffic is equal to or more than a
second threshold value.
[0007] The amount of traffic on the road is greatly affected by the
inter-vehicle distance and the vehicle speed. According to the
above-mentioned structure, when the amount of traffic increases and
is more than the first threshold value, the traveling control means
controls the inter-vehicle distance and the vehicle speed such that
the amount of traffic is a predetermined value equal to or more
than a second threshold value. Therefore, it is possible to
effectively suppress traffic congestion.
[0008] The traveling control means may change the inter-vehicle
distance and the vehicle speed at which the amount of traffic is
equal to or more than the second threshold value, depending on the
number of other vehicles which can communicate with the host
vehicle.
[0009] According to this structure, the traveling control means
changes the inter-vehicle distance and the vehicle speed at which
the amount of traffic is equal to or more than the second threshold
value, depending on the number of vehicles which can communicate
with the host vehicle and have high flexibility in the control of
the inter-vehicle distance and the vehicle speed by the host
vehicle. Therefore, it is possible to suppress traffic congestion
according to the actual situation.
[0010] The information acquiring means may acquire information
related to the number of other vehicles which cannot communicate
with the host vehicle between the host vehicle and other vehicles
which can communicate with the host vehicle, and the traveling
control means may change the inter-vehicle distance at which the
amount of traffic is equal to or more than the second threshold
value, depending on the number of other vehicles which cannot
communicate with the host vehicle between the host vehicle and
other vehicles which can communicate with the host vehicle related
to the information acquired by the information acquiring means.
[0011] According to this structure, the traveling control means
changes the inter-vehicle distance at which the amount of traffic
is equal to or more than the second threshold value, depending on
the number of vehicles which cannot communicate with the host
vehicle and have low flexibility in the control of the
inter-vehicle distance and the vehicle speed by the host vehicle.
Therefore, it is possible to perform vehicle control considering
the actual traffic conditions and traffic flow.
[0012] The traveling control means may change the first threshold
value, depending on a region including the road.
[0013] According to this structure, the first threshold value for
starting the control of the inter-vehicle distance and the vehicle
speed is changed depending on the region including the road.
Therefore, for example, when the road is in the region in which
traffic congestion occurs frequently, such as a sag section, the
first threshold value is changed depending on the region. In this
way, it is possible to effectively suppress traffic congestion.
[0014] When the traveling control means changes the inter-vehicle
distance and the vehicle speed at which the amount of traffic is
equal to or more than the second threshold value depending on the
number of other vehicles which can communicate with the host
vehicle, the information acquiring means may acquire information
related to the amount of traffic in each lane of the road, and the
traveling control means may control at least one of the
inter-vehicle distance and the vehicle speed on the basis of the
amount of traffic in each lane of the road related to the
information acquired by the information means.
[0015] The amount of traffic on the road is greatly affected by the
concentration of the amount of traffic in each lane. According to
this embodiment, the traveling control means controls at least one
of the inter-vehicle distance and the vehicle speed on the basis of
the amount of traffic in each lane of the road related to the
information acquired by the information means. Therefore, it is
possible to effectively suppress traffic congestion according to
the concentration of the amount of traffic in each lane.
[0016] According to another aspect of the invention, there is
provided a vehicle control method including: a step of acquiring
information related to the amount of traffic on a road on which a
host vehicle travels; and a step of, when the amount of traffic
related to the acquired information is more than a first threshold
value, controlling an inter-vehicle distance between the host
vehicle and other vehicles traveling on the road and the speed of
the host vehicle such that the amount of traffic is equal to or
more than a second threshold value.
[0017] In the step of controlling the inter-vehicle distance and
the vehicle speed such that the amount of traffic is equal to or
more than the second threshold value, the inter-vehicle distance
and the vehicle speed at which the amount of traffic is equal to or
more than the second threshold value may be changed depending on
the number of other vehicles which can communicate with the host
vehicle.
[0018] In the step of acquiring the information related to the
amount of traffic on the road on which the host vehicle travels,
information related to the number of other vehicles which cannot
communicate with the host vehicle between the host vehicle and
other vehicles which can communicate with the host vehicle may be
acquired. In the step of controlling the inter-vehicle distance and
the vehicle speed such that the amount of traffic is equal to or
more than the second threshold value, the inter-vehicle distance at
which the amount of traffic is equal to or more than the second
threshold value may be changed depending on the number of other
vehicles which cannot communicate with the host vehicle between the
host vehicle and other vehicles which can communicate with the host
vehicle related to the acquired information.
[0019] In the step of controlling the inter-vehicle distance and
the vehicle speed such that the amount of traffic is equal to or
more than the second threshold value, the first threshold value may
be changed depending on a region including the road.
[0020] In the step of acquiring the information related to the
amount of traffic on the road on which the host vehicle travels,
information related to the amount of traffic in each lane of the
road may be acquired. In the step of controlling the inter-vehicle
distance and the vehicle speed such that the amount of traffic is
equal to or more than the second threshold value, at least one of
the inter-vehicle distance and the vehicle speed may be controlled
on the basis of the amount of traffic in each lane of the road
related to the information acquired by the information means.
[0021] According to still another aspect of the invention, there is
provided a vehicle control system including: information acquiring
means for acquiring information related to the amount of traffic on
a road on which a plurality of vehicles travel; and traveling
control means for, when the amount of traffic related to the
information acquired by the information acquiring means is more
than a first threshold value, controlling an inter-vehicle distance
between at least two of the vehicles traveling on the road and the
speed of at least one of the vehicles such that the amount of
traffic is equal to or more than a second threshold value.
[0022] The traveling control means may change the inter-vehicle
distance and the vehicle speed at which the amount of traffic is
equal to or more than the second threshold value, depending on the
number of vehicles which can communicate with each other.
[0023] The information acquiring means may acquire information
related to the number of vehicles which cannot communicate with
each other between the vehicles which can communicate with each
other, and the traveling control means may change the inter-vehicle
distance at which the amount of traffic is equal to or more than
the second threshold value, depending on the number of vehicles
which cannot communicate with each other between the vehicles which
can communicate with each other related to the information acquired
by the information acquiring means.
[0024] The traveling control means may change the first threshold
value, depending on a region including the road.
[0025] The information acquiring means may acquire information
related to the amount of traffic in each lane of the road, and the
traveling control means may control at least one of the
inter-vehicle distance and the vehicle speed on the basis of the
amount of traffic in each lane of the road related to the
information acquired by the information means.
Advantageous Effects of Invention
[0026] According to the vehicle control device, the vehicle control
method, and the vehicle control system of the invention, it is
possible to effectively suppress traffic congestion.
BRIEF DESCRIPTION OF DRAWINGS
[0027] FIG. 1 is a block diagram illustrating the structure of a
vehicle control device according to a first embodiment.
[0028] FIG. 2 is a graph illustrating the relationship among the
amount of traffic, a vehicle speed, and an inter-vehicle distance
before and after traffic congestion occurs.
[0029] FIG. 3 is a graph illustrating a region in which traffic
congestion occurs and a region in which no traffic congestion
occurs in the relationship between the inter-vehicle distance and
the vehicle speed.
[0030] FIG. 4 is a plan view illustrating an example of a situation
in which the vehicle control device according to the first
embodiment is applied.
[0031] FIG. 5 is a flowchart illustrating an operation of guiding
the vehicle speed and the inter-vehicle distance.
[0032] FIG. 6 is a flowchart illustrating the details of the
operation of guiding the vehicle speed and the inter-vehicle
distance.
[0033] FIG. 7 is a flowchart illustrating the details of the
operation of guiding the vehicle speed and the inter-vehicle
distance.
[0034] FIG. 8 is a flowchart illustrating an operation of
maintaining the guided vehicle speed and inter-vehicle
distance.
[0035] FIG. 9 is a flowchart illustrating the details of the
operation of maintaining the guided vehicle speed and inter-vehicle
distance.
[0036] FIG. 10 is a flowchart illustrating the details of the
operation of maintaining the guided vehicle speed and inter-vehicle
distance.
[0037] FIG. 11 is a flowchart illustrating an operation of
returning the vehicle speed and the inter-vehicle distance to
normal values since the vehicle passes through a sag section.
[0038] FIG. 12 is a flowchart illustrating the details of the
operation of returning the vehicle speed and the inter-vehicle
distance to the normal values since the vehicle passes through the
sag section.
[0039] FIG. 13 is a flowchart illustrating a control operation for
a first communication vehicle in each lane.
[0040] FIG. 14 is a flowchart illustrating an operation when the
vehicle follows the leading vehicle.
[0041] FIG. 15 is a flowchart illustrating an operation of
maintaining the guided vehicle speed.
[0042] FIG. 16 is a block diagram illustrating the structure of a
vehicle control device according to a second embodiment.
[0043] FIG. 17 is a block diagram illustrating the structure of a
vehicle control device according to a third embodiment.
[0044] FIG. 18 is a plan view illustrating an example of a
situation in which the vehicle control device according to the
third embodiment is applied.
[0045] FIG. 19 is a graph illustrating the relationship between a
speed and the amount of traffic when the driver performs an
operation.
[0046] FIG. 20 is a flowchart illustrating the operation of the
vehicle control device according to the third embodiment.
[0047] FIG. 21 is graph illustrating the relationship between the
amount of traffic and the vehicle speed.
[0048] FIG. 22 is a graph illustrating a change in the vehicle
speed in a driving lane and the vehicle speed in a passing
lane.
[0049] FIG. 23 is a plan view illustrating the operation of the
vehicle control device according to the third embodiment.
[0050] FIG. 24 is a flowchart illustrating the operation of a
vehicle control device according to a fourth embodiment.
[0051] FIG. 25 is a plan view illustrating the operation of the
vehicle control device according to the fourth embodiment.
DESCRIPTION OF EMBODIMENTS
[0052] Hereinafter, a vehicle control device according to an
embodiment of the invention will be described with reference to the
accompanying drawings. The vehicle control device according to this
embodiment is provided in a vehicle and performs vehicle control
for improving the amount of traffic on the road. As shown in FIG.
1, a vehicle control device 10a according to this embodiment
includes a vehicle-to-vehicle communication device 12, a
road-to-vehicle communication device 14, a navigation system 16, an
ECU (Electronic Control Unit) 20, and an ACC (Adaptive Cruise
Control) 30.
[0053] The vehicle-to-vehicle communication device 12 performs
vehicle-to-vehicle communication to transmit or receive information
about the position or speed of system-provided vehicles other than
a host vehicle, or information indicating whether to turn on or off
vehicle control for preventing traffic congestion.
[0054] The road-to-vehicle communication device 14 receives
information, such as the amount of traffic on the road or the speed
of the vehicle traveling on the road, from a road infrastructure,
such as an optical beacon communication device. In this embodiment,
the road-to-vehicle communication device 14 is not necessarily
essential.
[0055] The navigation system 16 includes a GPS (Global Positioning
System) that receives signals from a plurality of GPS satellites
using a GPS receiver and measures the position of the host vehicle
from the difference between the signals and a map information DB
(Database) that stores the map information of the host vehicle. The
navigation system 16 guides the route of the host vehicle and
acquires information related to the position where the speed of the
vehicle in front of the host vehicle is reduced, such as a sag
section. For example, the navigation system 16 detects the position
of the host vehicle relative to the sag section and outputs the
position to the ECU 20.
[0056] The ECU 20 receives information related to the position of
the host vehicle relative to the sag section from the navigation
system 16 and receives information related to the relative position
and relative speed of other vehicles around the host vehicle from a
radar 32 of the ACC 30. In addition, the ECU outputs traveling
control command values, such as a target vehicle speed,
acceleration and deceleration G, and a target inter-vehicle
distance, to the ACC 30 on the basis of the information input from
the navigation system 16 and the ACC 30.
[0057] The ACC 30 includes the radar 32 that detects the relative
position and relative speed of other vehicles around the host
vehicle. The ACC 30 performs traveling control on the basis of the
traveling control command values from the ECU 20 such that the host
vehicle has the target vehicle speed, the acceleration and
deceleration G, and the target inter-vehicle distance.
[0058] Next, the operation of the vehicle control device 10a
according to this embodiment will be described. First, as a
premise, the principle of reducing traffic congestion in the
vehicle control device 10a according to this embodiment will be
described. As shown in FIGS. 2 and 3, in the relationship between
the amount of traffic and a vehicle speed, a region B in which
there is the largest margin in the amount of traffic is disposed at
a vehicle speed of about 60 km/h and an inter-vehicle distance of
about 40 m immediately before traffic congestion. However, in
practice, it is difficult to drive the vehicle while maintaining
the region B in which there is the largest margin in the amount of
traffic. When the inter-vehicle distance is gradually reduced,
deceleration propagation in which the deceleration of the leading
vehicle is sequentially propagated to the following vehicles
occurs, or deceleration is amplified by the deceleration
propagation. As a result, it is difficult to recover the vehicle
speed and traffic congestion occurs (N2).
[0059] The inter-vehicle distance becomes too short due to the
following causes. That is,
[0060] (1) The vehicle speed is gradually reduced (N1) and the
driver of the vehicle presses on his or her way to reduce the
inter-vehicle distance.
[0061] (2) At the position where the vehicle speed is locally
reduced, such as a sag section, traffic congestion occurs and the
amount of traffic increases partially.
[0062] As a method of preventing the traffic congestion, the
following methods are considered in which a road-side
infrastructure checks traffic conditions and predicts traffic
congestion on the basis of information from sensors which are
provided on the road, thereby preventing the traffic
congestion.
[0063] (A) A method of reducing traffic inflow using a route
distribution instruction
[0064] (B) A method of restricting traffic inflow into a traffic
congestion section by, for example, allowing the stopping and
starting of the vehicle
[0065] (C) A method of allowing the infrastructure side to instruct
a change in, for example, vehicle speed and lane
[0066] Alternatively, in order to prevent traffic congestion, the
following method is considered in which the infrastructure side
checks traffic conditions and predicts traffic congestion on the
basis of information from a probe car.
[0067] (D) A method of controlling a probe car such that a traffic
flow is controlled
[0068] However, since the methods (A) to (D) are performed on
condition that the infrastructure is installed, they are not
effective in the following traffic congestion.
[0069] (a) Traffic congestion which is likely to occur at any
position, such as traffic congestion caused by a breakdown, a
falling object, a broken-down car, and road construction
[0070] (b) Traffic congestion at the position where no
infrastructure is installed even though the occurrence of traffic
congestion has been determined
[0071] In particular, the method (A) is performed on condition that
there are (a plurality of) detour routes and is not used at
positions other than the central area of a metropolitan. In
addition, it is doubted whether the driver follows a detour
instruction for preventing traffic congestion, not a detour
instruction for avoiding traffic congestion which has occurred. In
addition, each driver is likely to feel unfair (for example,
difference in transit time or traveling distance) according to
whether a detour instruction is given to the vehicle, which is not
practical.
[0072] The method (B) has no effect of preventing traffic
congestion when traffic congestion occurs in an inflow restriction
portion. In the method (C), even when a vehicle speed and a driving
lane are instructed, traffic congestion occurs when the
inter-vehicle distance is reduced. Therefore, the method (C) may
have no effect according to the magnitude of the inter-vehicle
distance. In addition, even when the driving lanes of a large
number of vehicles are instructed, it is not expected that the
vehicles will be moved in the way that is intended to prevent the
concentration of the vehicles on the lanes. In addition, it is
difficult to provide desired control information, such as the
percentage and number of vehicles which are desired to change their
lanes, to the drivers using a display on the road. The method (D)
is suitable for a specific position and is a centralized method.
Therefore, the method (D) is a large-scale method requiring
standardization, which is not practical.
[0073] Therefore, in this embodiment, before traffic congestion
occurs, the inter-vehicle distance and speed of the vehicles are
guided to the region B in which there is the largest margin in the
amount of traffic, as shown in FIGS. 2 and 3 (S1). That is, vehicle
control is performed such that traffic congestion is less likely to
occur. Specifically, in this embodiment, the vehicle control is
performed by the following methods.
[0074] (1) When all the vehicles traveling on the road have a
communication function and are provided with a vehicle speed
control (for example, ACC/CC (Adaptive Cruise control/Cruise
Control)) system, vehicle control is performed such that each
vehicle has the above-mentioned inter-vehicle distance and vehicle
speed. That is, the system-provided vehicle is controlled or guided
to a vehicle speed and an inter-vehicle distance at which the
amount of traffic is the maximum, according to the vehicle
speed.
[0075] (2) When a general vehicle without including the system is
mixed on the road, vehicle control is performed such that the
system-provided vehicle predicts the number of general vehicles
between the system-provided vehicles and the inter-vehicle distance
is maintained using the sum of the inter-vehicle distances as an
upper limit.
[0076] (3) When the inter-vehicle distance is controlled to be long
after the vehicle enters a region in which the amount of traffic
increases partially, such as a sag section, deceleration occurs,
which results in traffic congestion. In order to prevent the
problem, the system-provided vehicle predicts an inter-vehicle time
(target inter-vehicle time) at the position (in the vicinity of the
position where traffic congestion occurs) where the vehicle speed
is the minimum before the sag section and starts vehicle speed and
inter-vehicle distance control before the inter-vehicle time is
equal or less than the predicted value. That is, the
system-provided vehicle changes a control start position depending
on the amount of traffic.
[0077] Next, the detailed operation of the vehicle control device
10a according to this embodiment will be described. As shown in
FIG. 4, it is assumed that system-provided vehicles 100a and 100b
provided with the vehicle control device 10a according to this
embodiment and a general vehicle 200 which is not provided with the
vehicle control device 10a travel together on a road 500. In each
lane, the system-provided vehicle 100b follows one leading
system-provided vehicle 100a. Several general vehicles 200 travel
between the system-provided vehicle 100a and the system-provided
vehicle 100b. The vehicle control device 10a of the following
system-provided vehicle 100b sets ACC1 and ACC2 sections in which
the system-provided vehicle 100b travels while performing
inter-vehicle control and CC1 and CC2 sections in which the
system-provided vehicle 100b travels while performing cruise
control, according to the distance relationship with the general
vehicle 200p which travels immediately in front of the
system-provided vehicle 100b.
[0078] First, the operation of the second or subsequent
system-provided vehicle 100b in each lane in a given section shown
in FIG. 4 will be described (S11). The length of the given section
is determined by the communicable distance between the
system-provided vehicles 100a and 100b. When the speed of the first
system-provided vehicle 100a in each lane is V.sub.P, the control
start relative speed of the second or subsequent second
system-provided vehicle 100b in each lane is V.sub.th, the speed of
the second or subsequent system-provided vehicle 100b in each lane
is V, and the relative speed difference V.sub.P-V is less than the
control start relative speed V.sub.th (V.sub.P-V.ltoreq.V.sub.th)
(S12), the vehicle control device 10a of the system-provided
vehicle 100b performs traveling control for guiding the vehicle
speed and the inter-vehicle distance (S13). For example, the time
when the amount of traffic reaches 40 to 80 vehicles/minute in two
lanes may be used as a traveling control start condition.
Alternatively, the vehicle speed and the inter-vehicle distance at
which the amount of traffic is obtained may be the traveling
control start condition.
[0079] When the speed V of the system-provided vehicle 100b
satisfies V>V.sub.OR or V>V.sub.OL (where V.sub.OR is the
initial speed of the system-provided vehicle 100b when the
system-provided vehicle 100b travels in a passing lane and
traveling control starts and V.sub.OR is the initial speed of the
system-provided vehicle 100b when the system-provided vehicle 100b
travels in a driving lane and traveling control starts) (S14), the
vehicle control device 10a of the system-provided vehicle 100b
controls the speed V of the system-provided vehicle 100b such that
the speed V and the initial speeds satisfy the relationship
V=V.sub.OR or V>V.sub.OL (S15).
[0080] When the target speed of the system-provided vehicle 100b is
V.sub.Rt, the additional upper limit of the target speed of the
system-provided vehicle 100b is V.sub.d, the speed V of the
system-provided vehicle 100b satisfies V.ltoreq.V.sub.Rt+V.sub.d
(S16), the vehicle control device 10a of the system-provided
vehicle 100b performs the subsequent steps. When the speed V of the
system-provided vehicle 100b satisfies V>V.sub.Rt+V.sub.d (S16),
the vehicle control device 10a of the system-provided vehicle 100b
performs Steps S13 to S16 again. The target vehicle speed V.sub.Rt
is appropriately changed depending on, for example, the number of
other system-provided vehicles 100a and 100b within the
communicable distance, the number of general vehicles 200, and
whether there are a sag section, a curved road, a tunnel, and
gradient in the region including the road 500. For example, the
target vehicle speed V.sub.Rt may be set in the range of 40 km/h to
80 km/h and preferably, in the range of 60 km/h to 75 km/h.
[0081] Next, the operation of guiding the vehicle speed and the
inter-vehicle distance in Step S13 will be described in detail. As
shown in a case C1 of FIGS. 6 and 4, when the distance headway (the
distance between the heads of two vehicles) between the
system-provided vehicle 100b and a general vehicle 200p which is
immediately in front of the system-provided vehicle 100b is
L.sub.R, the speed of the general vehicle 200p is V.sub.pre, the
distance headway between the leading system-provided vehicle 100a
and the system-provided vehicle 100b is L.sub.C, a predicted
distance headway between the leading system-provided vehicle 100a
and the vehicle which is immediately in front of the
system-provided vehicle 100b is L.sub.RL, the predicted distance
headway satisfies L.sub.C-L.sub.R<L.sub.RL, and the general
vehicle 200p which is immediately in front of the system-provided
vehicle 100b is within the predicted distance headway L.sub.RL,
(S13a), the vehicle control device 10a of the system-provided
vehicle 100b performs Step S13b.
[0082] The predicted distance headway L.sub.RL between the leading
system-provided vehicle 100a and the general vehicle 200p which is
immediately in front of the system-provided vehicle 100b is
calculated by the product of a target time headway T.sub.RL between
the leading system-provided vehicle 100a and the general vehicle
200p which is immediately in front of the system-provided vehicle
100b and the target speed V.sub.Rt of the leading system-provided
vehicle 100a (L.sub.RL=T.sub.RLV.sub.Rt).
[0083] It is assumed that the estimated value of the number of
general vehicles 200 between the leading system-provided vehicle
100a and the system-provided vehicle 100b is N. When a predicted
time headway between the general vehicles 200 which travel in the
passing lane is T.sub.preR and a predicted time headway between the
general vehicles 200 which travel in the driving lane is
T.sub.preL, the estimated value N of the number of general vehicles
200 between the leading system-provided vehicle 100a and the
system-provided vehicle 100b can be calculated as follows:
N=(L.sub.C-L.sub.R)/(T.sub.PreR-V.sub.p) or
N=(L.sub.C-L.sub.R)/(T.sub.preLV.sub.p). The predicted time
headways T.sub.preR and T.sub.preL between the general vehicles 200
or the number of general vehicles 200 may be estimated by observing
the distance from the vehicle which travels in an adjacent lane
using the radar 32.
[0084] When a target guide time headway between the general
vehicles 200 is k.sub.TL and the margin of the predicted time
headway between the general vehicles 200 is k.sub.RT0, the target
time headway T.sub.RL between the leading system-provided vehicle
100a and the general vehicle 200p which is immediately in front of
the system-provided vehicle 100b is calculated as follows:
T.sub.RL=func(N)=k.sub.TLN+k.sub.RT0.
[0085] In addition, the target distance headway L.sub.Rt between
the system-provided vehicle 100b and the general vehicle 200p which
is immediately in front of the system-provided vehicle 100b is
calculated by the product of the target speed V.sub.Rt of the
system-provided vehicle 100b and a target time headway T.sub.Rt
between the system-provided vehicle 100b and the vehicle which is
immediately in front of the system-provided vehicle 100b
(L.sub.Rt=V.sub.RtT.sub.Rt).
[0086] When
L.sub.RL+L.sub.Rt<L.sub.C<L.sub.RL+L.sub.Rt+L.sub.RC0 is not
satisfied (S13b), that is, when the system-provided vehicle 100b is
not in the CC1 section shown in FIG. 4 from the distance
relationship with the general vehicle 200p which is immediately in
front of the system-provided vehicle 100b, the vehicle control
device 10a of the system-provided vehicle 100b performs steps after
Step S13c.
[0087] When L.sub.C.gtoreq.L.sub.RL+L.sub.Rt+L.sub.RC0 is not
satisfied (S13c), that is, when the system-provided vehicle 100b is
in the ACC1 section, not the CC2 section, in FIG. 4 in the distance
relationship with the general vehicle 200p which is immediately in
front of the system-provided vehicle 100b, the vehicle control
device 10a of the system-provided vehicle 100b performs Step S13d.
In this case, the vehicle control device 10a of the system-provided
vehicle 100b sets a target acceleration calculation intermediate
value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.L((L.sub.RL+L.sub.Rt)-L.sub.C) is
established (S13d) (where k.sub..alpha.L is an acceleration gain
when ACC is performed). That is, the vehicle control device 10a
controls the system-provided vehicle 100b so as to move from the
ACC1 section to the CC1 section.
[0088] In Step S13d, when
L.sub.RL+L.sub.Rt<L.sub.C<L.sub.RL+L.sub.Rt+L.sub.RC0 is
satisfied, that is, when the system-provided vehicle 100b is in the
CC1 section in FIG. 4, the vehicle control device 10a of the
system-provided vehicle 100b sets the target acceleration
calculation intermediate value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V(V.sub.p-V) is established (where
k.sub..alpha.V is an acceleration gain when CC is performed)
(S13f). That is, the vehicle control device 10a controls the
system-provided vehicle 100b so as to stay in the CC1 section.
[0089] In Step S13c, when
L.sub.C.gtoreq.L.sub.RL+L.sub.Rt+L.sub.RC0 is satisfied, that is,
when the system-provided vehicle 100b is in the CC2 section in FIG.
4, the vehicle control device 10a of the system-provided vehicle
100b sets the target acceleration calculation intermediate value
.alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V((V.sub.p+V.sub.d)-V) is established
(S13g). That is, the vehicle control device 10a controls the
system-provided vehicle 100b such that the distance between the
system-provided vehicle 100b and the general vehicle 200p which is
immediately in front of the system-provided vehicle 100b is reduced
and the system-provided vehicle 100b moves from the CC2 section to
the CC1 section.
[0090] In Step S13a, as shown in a case C2 of FIG. 4, when
L.sub.C-L.sub.R<L.sub.RL is not satisfied and the general
vehicle 200p which is immediately in front of the system-provided
vehicle 100b is not within the predicted distance headway L.sub.RL
(S13a), the vehicle control device 10a of the system-provided
vehicle 100b performs Step S13e.
[0091] As shown in detail in FIG. 7, in Step S13e, when
L.sub.R<L.sub.Rt is not satisfied (S13e-1) and
L.sub.Rt.ltoreq.L.sub.R<L.sub.Rt+L.sub.RC1 is not satisfied
(where L.sub.RC1 is the distance of the ACC2 section in which the
relative vehicle speed is adjusted in the case C2) (S13e-2), that
is, when the actual distance headway is more than the target
distance headway and the system-provided vehicle 100b is out of the
ACC2 section in which the relative vehicle speed is adjusted, the
vehicle control device 10a of the system-provided vehicle 100b sets
the target acceleration calculation intermediate value
.alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V((V.sub.p+V.sub.d)-V) is established
(S13e-3). That is, the vehicle control device 10a controls the
system-provided vehicle 100b so as to move to the ACC2 section in
the case C2 of FIG. 4.
[0092] In Step S13g-1, when L.sub.R<L.sub.Rt is satisfied
(S13e-1), that is, when the actual distance headway is less than
the target distance headway and the system-provided vehicle 100b is
in the ACC2 section, the vehicle control device 10a of the
system-provided vehicle 100b sets the target acceleration
calculation intermediate value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.L(L.sub.Rt-L.sub.R) is established
(S13e-3). That is, the vehicle control device 10a controls the
system-provided vehicle 100b so as to travel while maintaining the
distance headway between the system-provided vehicle 100b and the
general vehicle 200p which is immediately in front of the
system-provided vehicle 100b to be the target inter-vehicle
distance L.sub.Rt.
[0093] In Step S13g-2, when
L.sub.Rt.ltoreq.L.sub.R<L.sub.Rt+L.sub.RC1 is satisfied
(S13e-2), that is, when the actual distance headway is more than
the target distance headway and the system-provided vehicle 100b is
in the ACC2 section in which the relative vehicle speed is
adjusted, the vehicle control device 10a of the system-provided
vehicle 100b sets the target acceleration calculation intermediate
value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V((V.sub.pre+V.sub.k)-V) is established
(where V.sub.k is a target value of the speed of the
system-provided vehicle 100b relative to the speed V.sub.pre of the
general vehicle 200p which is immediately in front of the
system-provided vehicle 100b in the ACC section in which the
relative vehicle speed is adjusted) (S13e-5). That is, the vehicle
control device 10a controls the system-provided vehicle 100b such
that the relative speed thereof to the general vehicle 200p which
is immediately in front of the system-provided vehicle 100b is
equal to the target value V.sub.k and the system-provided vehicle
100b moves to the ACC2 section in the case C2 of FIG. 4.
[0094] Returning to FIG. 6, when the maximum acceleration of the
acceleration side is .alpha..sub.a, the maximum acceleration of the
deceleration side is .alpha..sub.d, and
.alpha..sub.tc>.alpha..sub.a or .alpha..sub.tc<.alpha..sub.d
is satisfied (S13h), that is, when the target acceleration
calculation intermediate value .alpha..sub.tc is more than the
maximum acceleration .alpha..sub.a or .alpha..sub.d of the
acceleration side or the deceleration side, the vehicle control
device 10a of the system-provided vehicle 100b sets a target
acceleration .alpha..sub.t of the system-provided vehicle to be
equal to the maximum acceleration .alpha..sub.a or .alpha..sub.d
(.alpha..sub.t=.alpha..sub.a or .alpha..sub.t=.alpha..sub.d)
(S13i). When .alpha..sub.tc>.alpha..sub.a or
.alpha..sub.tc<.alpha..sub.d is not satisfied (S13h), that is,
when the target acceleration calculation intermediate value
.alpha..sub.tc is not more than the maximum acceleration
.alpha..sub.a or .alpha..sub.d of the acceleration side or the
deceleration side, the vehicle control device 10a of the
system-provided vehicle 100b sets the target acceleration
.alpha..sub.t of the system-provided vehicle to be equal to the
target acceleration calculation intermediate value .alpha..sub.tc
(.alpha..sub.t=.alpha..sub.tc) (S13j).
[0095] As described with reference to FIGS. 5 to 7, after the
vehicle control device 10a of the system-provided vehicle 100b
performs control for guiding the vehicle speed and the
inter-vehicle distance, it performs control for maintaining the
guided vehicle speed and inter-vehicle distance, as shown in FIG. 8
(S17). When V>V.sub.Rt+V.sub.d is satisfied, that is, when the
speed V of the system-provided vehicle 100b is more than the sum of
the target vehicle speed V.sub.Rt and the target vehicle speed
added upper limit V.sub.d (S18), the vehicle control device 10a of
the system-provided vehicle 100b sets the speed V such that
V=V.sub.Rt+V.sub.d is established (S19). The system-provided
vehicle 100b which has been decelerated to V.sub.Rt+V.sub.d once is
controlled to travel using the speed V=V.sub.Rt+V.sub.d as the
upper limit speed.
[0096] Next, the operation of maintaining the guided vehicle speed
and inter-vehicle distance in Step S17 will be described in detail.
As shown in the case C1 of FIGS. 9 and 4, when
L.sub.C-L.sub.R<L.sub.RL is satisfied and the general vehicle
200p which is immediately in front of the system-provided vehicle
100b is within the predicted distance headway L.sub.RL (S17a), the
vehicle control device 10a of the system-provided vehicle 100b
performs Step S17b. When
L.sub.RL+L.sub.Rt<L.sub.C<L.sub.RL+L.sub.Rt+L.sub.RC0 is not
satisfied (S17b), that is, when the system-provided vehicle 100b is
not in the CC1 section of FIG. 4 from the distance relationship
with the general vehicle 200p which is immediately in front of the
system-provided vehicle 100b, the vehicle control device 10a of the
system-provided vehicle 100b performs Step S17c.
[0097] When L.sub.C.gtoreq.L.sub.RL+L.sub.Rt+L.sub.RC0 is not
satisfied (S17c), that is, when the system-provided vehicle 100b is
in the ACC1 section of FIG. 4, not the CC2 section, in the distance
relationship with the general vehicle 200p which is immediately in
front of the system-provided vehicle 100b, the vehicle control
device 10a of the system-provided vehicle 100b performs Step S17d.
In this case, the vehicle control device 10a of the system-provided
vehicle 100b sets the target acceleration calculation intermediate
value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.L((L.sub.RL+L.sub.Rt)-L.sub.C) is
established (S17d). That is, the vehicle control device 10a
controls the system-provided vehicle 100b so as to move from the
ACC1 section to the CC1 section.
[0098] In Step S17b, when
L.sub.RL+L.sub.Rt<L.sub.C<L.sub.RL+L.sub.Rt+L.sub.RC0 is
satisfied, that is, when the system-provided vehicle 100b is in the
CC1 section of FIG. 4, the vehicle control device 10a of the
system-provided vehicle 100b sets the target acceleration
calculation intermediate value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V(V.sub.Rt-V) is established (S170.
That is, the vehicle control device 10a controls the
system-provided vehicle 100b so as to stay in the CC1 section.
[0099] In Step S17c, when
L.sub.C.gtoreq.L.sub.RL+L.sub.Rt+L.sub.RC0 is satisfied, that is,
when the system-provided vehicle 100b is in the CC2 section of FIG.
4, the vehicle control device 10a of the system-provided vehicle
100b sets the target acceleration calculation intermediate value
.alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V((V.sub.Rt+V.sub.d)-V) is established
(S17g). That is, the vehicle control device 10a controls the
system-provided vehicle 100b such that the inter-vehicle distance
between the system-provided vehicle 100b and the general vehicle
200p which is immediately in front of the system-provided vehicle
100b is reduced and the system-provided vehicle 100b is moved from
the CC2 section to the CC1 section.
[0100] In Step S17a, as shown in the case C2 of FIG. 4, when
L.sub.C-L.sub.R<L.sub.RL is not satisfied and the general
vehicle 200p which is immediately in front of the system-provided
vehicle 100b is not within the predicted distance headway L.sub.RL
(S17a), the vehicle control device 10a of the system-provided
vehicle 100b performs Step S17e.
[0101] As shown in detail in FIG. 10, in Step S17e, when
L.sub.R<L.sub.Rt is not satisfied (S17e-1) and
L.sub.Rt.ltoreq.L.sub.R<L.sub.Rt+L.sub.RC1 is not satisfied
(where L.sub.RC1 is the distance of the ACC2 section in which the
relative vehicle speed is adjusted in the case C2) (S17e-2), that
is, when the actual distance headway is more than the target
distance headway and the system-provided vehicle 100b is out of the
ACC2 section in which the relative vehicle speed is adjusted, the
vehicle control device 10a of the system-provided vehicle 100b sets
the target acceleration calculation intermediate value
.alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V((V.sub.p+V.sub.d)-V) is established
(S17e-3). That is, the vehicle control device 10a controls the
system-provided vehicle 100b so as to move to the ACC2 section in
the case C2 of FIG. 4.
[0102] In Step S17e-1, when L.sub.R<L.sub.Rt is satisfied
(S17e-1), that is, when the actual distance headway is less than
the target distance headway and the system-provided vehicle 100b is
in the ACC2 section, the vehicle control device 10a of the
system-provided vehicle 100b sets the target acceleration
calculation intermediate value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.L(L.sub.Rt-L.sub.R) is established
(S17e-3). That is, the vehicle control device 10a controls the
system-provided vehicle 100b so as travel while maintaining the
distance headway between the system-provided vehicle 100b and the
general vehicle 200p which is immediately in front of the
system-provided vehicle 100b to be the target inter-vehicle
distance L.sub.Rt.
[0103] In Step S17g-2, when
L.sub.Rt.ltoreq.L.sub.R<L.sub.Rt+L.sub.RC1 is satisfied
(S17e-2), that is, when the actual distance headway is more than
the target distance headway and the system-provided vehicle 100b is
in the ACC2 section in which the relative vehicle speed is
adjusted, the vehicle control device 10a of the system-provided
vehicle 100b sets the target acceleration calculation intermediate
value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V((V.sub.pre+V.sub.k)-V) is established
(where V.sub.k is a target value of the relative vehicle speed in
the ACC section in which the relative vehicle speed is adjusted)
(S17e-5). That is, the vehicle control device 10a controls the
system-provided vehicle 100b such that the relative speed thereof
to the general vehicle 200p is equal to the target value V.sub.k
and the system-provided vehicle 100b moves to the ACC2 section in
the case C2 of FIG. 4.
[0104] Returning to FIG. 9, when .alpha..sub.tc>.alpha..sub.a or
.alpha..sub.tc<.alpha..sub.d is satisfied (S17h), that is, when
the target acceleration calculation intermediate value
.alpha..sub.tc is more than the maximum acceleration .alpha..sub.a
or .alpha..sub.d of the acceleration side or the deceleration side,
the vehicle control device 10a of the system-provided vehicle 100b
sets the target acceleration .alpha..sub.t of the system-provided
vehicle to be equal to the maximum acceleration .alpha..sub.a or
.alpha..sub.d (.alpha..sub.t=.alpha..sub.a or
.alpha..sub.t=.alpha..sub.d) (S17i). When
.alpha..sub.tc>.alpha..sub.d or .alpha..sub.tc<.alpha..sub.d
is not satisfied (S17h), that is, when the target acceleration
calculation intermediate value .alpha..sub.tc is not more than the
maximum acceleration .alpha..sub.a or .alpha..sub.d of the
acceleration side or the deceleration side, the vehicle control
device 10a of the system-provided vehicle 100b sets the target
acceleration .alpha..sub.t of the system-provided vehicle to be
equal to the target acceleration calculation intermediate value
.alpha..sub.tc (.alpha..sub.t=.alpha..sub.tc) (S17j).
[0105] As described with reference to FIGS. 8 to 10, after the
vehicle control device 10a of the system-provided vehicle 100b
performs control for maintaining the guided vehicle speed and
inter-vehicle distance, it performs control for returning to a
normal vehicle speed and inter-vehicle distance since the
system-provided vehicle 100b has passed through the sag section, as
shown in FIG. 8 (S20).
[0106] When the speed V of the system-provided vehicle 100b is more
than the initial vehicle speed V.sub.OR or V.sub.OL (V>V.sub.OR
or V>V.sub.OL) (S21), the vehicle control device 10a of the
system-provided vehicle 100b performs traveling control such that
the speed V of the system-provided vehicle 100b is equal to the
initial vehicle speed (V=V.sub.OR=V.sub.OL) (S22). The position
X.sub.pre of the general vehicle 200p which is immediately in front
of the system-provided vehicle 100b reaches the final position
X.sub.max of a controllable section (S23), the vehicle control
device 10a of the system-provided vehicle 100b sets the distance
L.sub.R from the general vehicle 200p which is immediately in front
of the system-provided vehicle 100b to a fixed value (S24) and
repeatedly performs Steps S20 to S23.
[0107] Next, the operation of returning the vehicle speed and the
inter-vehicle distance to normal values since the system-provided
vehicle 100b passes through the sag section in Step S20 will be
described in detail. As shown in FIG. 12, when L.sub.R<L.sub.Rt
is not satisfied (S20a) and
L.sub.Rt.ltoreq.L.sub.R<L.sub.Rt+L.sub.RC2 is not satisfied
(where L.sub.RC2 is the distance of the ACC section in which the
relative vehicle speed is adjusted after the sag section ends
(S20b), that is, when the actual distance headway is more than the
target distance headway and the system-provided vehicle 100b is out
of the ACC section in which the relative vehicle speed is adjusted
after the sag section ends, the vehicle control device 10a of the
system-provided vehicle 100b sets the target acceleration
calculation intermediate value .alpha..sub.tc such that
.alpha..sub.tc=.alpha..sub..alpha.V(V.sub.OR-V) or
.alpha..sub.tc=k.sub..alpha.v(V.sub.OL-V) is established (S20c).
That is, the vehicle control device 10a controls the
system-provided vehicle 100b so as to travel at the vehicle speed
initial values V.sub.OR and V.sub.OL of each lane.
[0108] In Step S20a, when L.sub.R<L.sub.Rt is satisfied (S20a),
that is, the actual distance headway less than the target distance
headway and the system-provided vehicle 100b is in an ACC section,
the vehicle control device 10a of the system-provided vehicle 100b
sets the target acceleration calculation intermediate value
.alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.L(L.sub.Rt-L.sub.R) is established
(S20c). That is, the vehicle control device 10a controls the
system-provided vehicle 100b so as to travel while maintaining the
distance headway between the system-provided vehicle 100b and the
general vehicle 200p which is immediately in front of the
system-provided vehicle 100b to be the target inter-vehicle
distance L.sub.Rt.
[0109] In Step S21d, when
L.sub.Rt.ltoreq.L.sub.R<L.sub.Rt+L.sub.RC2 is satisfied (S20b),
that is, when the actual distance headway is more than the target
distance headway and the system-provided vehicle 100b is in the ACC
section in which the relative vehicle speed is adjusted after the
sag section ends, the vehicle control device 10a of the
system-provided vehicle 100b sets the target acceleration
calculation intermediate value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V((V.sub.pre+V.sub.k)-V) is established
(where V.sub.k is the target value of the relative vehicle speed in
the ACC section in which the relative vehicle speed is adjusted
(S20e). That is, the vehicle control device 10a controls the
system-provided vehicle 100b such that the relative speed thereof
to the general vehicle 200p which is immediately in front of the
system-provided vehicle 100b is the target value V.sub.k and the
system-provided vehicle 100b moves to the ACC section.
[0110] When .alpha..sub.tc>.alpha..sub.a or
.alpha..sub.tc<.alpha..sub.d is satisfied (S200, that is, when
the target acceleration calculation intermediate value
.alpha..sub.tc is more than the maximum acceleration .alpha..sub.a
or .alpha..sub.d of the acceleration side or the deceleration side,
the vehicle control device 10a of the system-provided vehicle 100b
sets the target acceleration .alpha..sub.t of the system-provided
vehicle to be equal to the maximum acceleration .alpha..sub.a or
.alpha..sub.d (.alpha..sub.t=.alpha..sub.a or
.alpha..sub.t=.alpha..sub.d) (S20g). When
.alpha..sub.tc>.alpha..sub.a or .alpha..sub.tc<.alpha..sub.d
is not satisfied (S200, that is, when the target acceleration
calculation intermediate value .alpha..sub.tc is not more than the
maximum acceleration .alpha..sub.a or .alpha..sub.d of the
acceleration side or the deceleration side, the vehicle control
device 10a of the system-provided vehicle 100b sets the target
acceleration .alpha..sub.t of the system-provided vehicle to be
equal to the target acceleration calculation intermediate value
.alpha..sub.tc (.alpha..sub.t=.alpha..sub.tc) (S20h).
[0111] Next, the operation of the first system-provided vehicle
100a in each lane in a given section shown in FIG. 4 will be
described (S11). As shown in FIG. 13, when the coordinate X of the
system-provided vehicle 100a in the traveling direction reaches a
position X.sub.on where vehicle speed control starts (S25) and the
speed V of the system-provided vehicle 100a is more than the target
vehicle speed V.sub.Rt (V.ltoreq.V.sub.Rt) (S26), the vehicle
control device 10a of the system-provided vehicle 100a performs a
process when the system-provided vehicle 100a has followed the
vehicle in front (S27).
[0112] Next, the process when the system-provided vehicle 100a has
followed the vehicle in front Step S27 will be described in detail.
As shown in FIG. 14, when L.sub.R<L.sub.Rt is not satisfied
(S27a) and L.sub.Rt.ltoreq.L.sub.R<L.sub.Rt+L.sub.RC4 and
V>V.sub.pre are not satisfied (where L.sub.RC4 is the distance
of the ACC section in which the relative vehicle speed is adjusted
during the guidance of the first system-provided vehicle 100a)
(S27b), that is, when the actual distance headway is more than the
target distance headway, the system-provided vehicle 100a is out of
the ACC section in which the relative vehicle speed is adjusted
during the guidance of the first system-provided vehicle 100a, the
speed V of the system-provided vehicle 100a is less than the speed
V.sub.pre of the general vehicle 200p which is immediately in front
of the system-provided vehicle 100a, the vehicle control device 10a
of the system-provided vehicle 200a sets the target acceleration
calculation intermediate value .alpha..sub.tb such that
.alpha..sub.tb=(V.sub.Rt.sup.2-V.sub.Xon.sup.2)/2X.sub.d is
established (S27c).
[0113] V.sub.Xon is the speed of the first system-provided vehicle
100a in each lane when the first system-provided vehicle 100a
passes through the position X.sub.on and X.sub.d is the distance of
the section in which the first system-provided vehicle 100a is
initially decelerated. That is, the vehicle control device 10a
controls the traveling of the system-provided vehicle 100a such
that the vehicle speed is V.sub.Rt only in the initial section
corresponding to the distance X.sub.d.
[0114] In Step S27a, when L.sub.R<L.sub.Rt is satisfied (S27a),
that is, the actual distance headway is less than the target
distance headway and the system-provided vehicle 100a is in the ACC
section, the vehicle control device 10a of the system-provided
vehicle 100a sets the target acceleration calculation intermediate
value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.L(L.sub.Rt-L.sub.R) is established
(S27c). That is, the vehicle control device 10a controls the
system-provided vehicle 100a so as to travel while maintaining the
distance headway between the system-provided vehicle 100a and the
general vehicle 200p which is immediately in front of the
system-provided vehicle 100a to be the target inter-vehicle
distance L.sub.Rt.
[0115] In Step S27b, when
L.sub.Rt.ltoreq.L.sub.R<L.sub.Rt+L.sub.RC4 and V>V.sub.pre
are satisfied (S27b), that is, the actual distance headway is more
than the target distance headway, the first system-provided vehicle
100a is out of the ACC section in which the relative vehicle speed
is adjusted during guidance, and the speed V of the first
system-provided vehicle 100a is more than the speed V.sub.pre of
the general vehicle 200p in front, the vehicle control device 10a
of the system-provided vehicle 100a sets the target acceleration
calculation intermediate value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V((V.sub.pre+V.sub.k)-V) is established
(where V.sub.k is a target value of the relative vehicle speed in
the ACC section in which the relative vehicle speed is adjusted
(S27e). That is, the vehicle control device 10a controls the
system-provided vehicle 100a such that the relative speed thereof
to the general vehicle 200p immediately in front is equal to the
target value V.sub.k and the system-provided vehicle 100a moves to
the ACC section.
[0116] In Steps S27d and S27e, when .alpha..sub.tc>.alpha..sub.a
or .alpha..sub.tc<.alpha..sub.d is satisfied (S27f), that is,
the target acceleration calculation intermediate value
.alpha..sub.tc is more than the maximum acceleration .alpha..sub.a
or .alpha..sub.d of the acceleration side or the deceleration side,
the vehicle control device 10a of the system-provided vehicle 100a
sets the target acceleration .alpha..sub.t of the system-provided
vehicle to be equal to the maximum acceleration .alpha..sub.a or
.alpha..sub.d (.alpha..sub.t=.alpha..sub.a or
.alpha..sub.t=.alpha..sub.d) (S27g).
[0117] In Step S27c, S27f, or S27g, when
.alpha..sub.tb.ltoreq..alpha..sub.tc is satisfied (S27h), the
vehicle control device 10a of the system-provided vehicle 100a sets
the target acceleration .alpha..sub.t such that
.alpha..sub.t=.alpha..sub.tb is established (S27i). In Step S27c,
527f, or S27g, when .alpha..sub.tb>.alpha..sub.tc is satisfied
(S27h), the vehicle control device 10a of the system-provided
vehicle 100a sets the target acceleration .alpha..sub.t such that
.alpha..sub.t=.alpha..sub.tc is established (S27j).
[0118] Returning to FIG. 13, in Step S26, when the speed V of the
system-provided vehicle 100a is equal to or less than the target
vehicle speed V.sub.Rt (V.ltoreq.V.sub.Rt) (S26), the vehicle
control device 10a of the system-provided vehicle 100a performs
control to maintain the guided vehicle speed (S28).
[0119] Next, the control process of maintaining the guided vehicle
speed in Step S28 will be described in detail. As shown in FIG. 15,
when L.sub.R<L.sub.Rt is not satisfied (S28a) and
L.sub.Rt.ltoreq.L.sub.R<L.sub.Rt+L.sub.RC3 is not satisfied
(where L.sub.RC3 is the distance of the ACC section in which the
relative vehicle speed is adjusted when the speed of the first
system-provided vehicle 100a is maintained) (S28b), that is, when
the actual distance headway is more than the target distance
headway and the first system-provided vehicle 100a is out of the
ACC section in which the relative vehicle speed is adjusted when
the vehicle speed is maintained, the vehicle control device 10a of
the system-provided vehicle 100a sets the target acceleration
calculation intermediate value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V(V.sub.Rt-V) is established (S28c).
That is, the vehicle control device 10a controls the
system-provided vehicle 100a so as to travel at the target vehicle
speed V.sub.Rt.
[0120] In Step S29a, when L.sub.R<L.sub.Rt is satisfied (S28a),
that is, the actual distance headway is less than the target
distance headway and the system-provided vehicle 100a is in the ACC
section, the vehicle control device 10a of the system-provided
vehicle 100a sets the target acceleration calculation intermediate
value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.L(L.sub.Rt-L.sub.R) is established
(S28d). That is, the vehicle control device 10a controls the
system-provided vehicle 100a so as to travel while maintaining the
distance headway between the system-provided vehicle 100a and the
general vehicle 200p immediately in front to be the target
inter-vehicle distance L.sub.Rt.
[0121] In Step S28b, when
L.sub.Rt.ltoreq.L.sub.R<L.sub.Rt+L.sub.RC3 is satisfied (S28b),
that is, when the actual distance headway is more than the target
distance headway and the system-provided vehicle 100a is in the ACC
section in which the relative vehicle speed is adjusted during the
maintenance of the vehicle speed, the vehicle control device 10a of
the system-provided vehicle 100a sets the target acceleration
calculation intermediate value .alpha..sub.tc such that
.alpha..sub.tc=k.sub..alpha.V((V.sub.pre+V.sub.k)-V) is established
(where V.sub.k is the target value of the relative vehicle speed in
the ACC section in which the relative vehicle speed is adjusted)
(S28e). That is, the vehicle control device 10a controls the
system-provided vehicle 100a such that the relative speed thereof
to the general vehicle 200p immediately in front is equal to the
target value V.sub.k and the system-provided vehicle 100a moves to
the ACC section.
[0122] When .alpha..sub.tc>.alpha..sub.a or
.alpha..sub.tc<.alpha..sub.d is satisfied (S28f), that is, the
target acceleration calculation intermediate value .alpha..sub.tc
is more than the maximum acceleration .alpha..sub.a or
.alpha..sub.d of the acceleration side or the deceleration side,
the vehicle control device 10a of the system-provided vehicle 100a
sets the target acceleration .alpha..sub.t of the system-provided
vehicle to be equal to the maximum acceleration .alpha..sub.a or
.alpha..sub.d (.alpha..sub.t=.alpha..sub.a or
.alpha..sub.t=.alpha..sub.d) (S28g). When
.alpha..sub.tc>.alpha..sub.a or .alpha..sub.tc<.alpha..sub.d
is not satisfied (S28f), that is, when the target acceleration
calculation intermediate value .alpha..sub.tc is not more than the
maximum acceleration .alpha..sub.a or .alpha..sub.d of the
acceleration side or the deceleration side, the vehicle control
device 10a of the system-provided vehicle 100a sets the target
acceleration .alpha..sub.t of the system-provided vehicle to be
equal to the target acceleration calculation intermediate value
.alpha..sub.tc (.alpha..sub.t=t.sub.tc (S28h).
[0123] Returning to FIG. 13, when V>V.sub.Rt is satisfied, that
is, when the speed V of the system-provided vehicle 100a is more
than the target vehicle speed V.sub.Rt (S29), the vehicle control
device 10a of the system-provided vehicle 100a sets the speed V to
be equal to V.sub.Rt and controls the system-provided vehicle 100a
so as to travel using the speed V=V.sub.Rt as the upper limit
speed.
[0124] The amount of traffic on the road is greatly affected by
both the inter-vehicle distance and the vehicle speed. According to
this embodiment, when the amount of traffic is increases and is
more than a threshold value, the ECU 20 and the ACC 30 controls the
inter-vehicle distance and the vehicle speed such that the amount
of traffic becomes a value equal to or more than the threshold
value. In this way, it is possible to effectively suppress traffic
congestion.
[0125] In this embodiment, the ECU 20 and the ACC 30 changes the
inter-vehicle distance and the vehicle speed such that the amount
of traffic is equal to or more than the threshold value, according
to the number of system-provided vehicles 100a or 100b which can
communicate with the system-provided vehicle 100a or 100b, which is
the host vehicle, and have high flexibility in the control of the
inter-vehicle distance and the vehicle speed by the host vehicle.
Therefore, it is possible to suppress traffic congestion according
to the actual situation.
[0126] In this embodiment, the ECU 20 and the ACC 30 changes the
inter-vehicle distance such that the amount of traffic is equal to
or more than the threshold value, according to the number N of
general vehicles 200 disposed between the system-provided vehicles
100a or 100b which can communicate with the system-provided vehicle
100a or 100b, which is the host vehicle, and have low flexibility
in the control of the inter-vehicle distance and the vehicle speed
by the host vehicle. Therefore, it is possible to perform vehicle
control considering the actual traffic conditions and traffic
flow.
[0127] In this embodiment, the ECU 20 and the ACC 30 change the
threshold value for starting the control of the inter-vehicle
distance and the vehicle speed, depending on the region including
the road. Therefore, for example, when the road is in the region in
which traffic congestion occurs frequently, such as a sag section,
the ECU 20 and the ACC 30 change the threshold value depending on
the region. Therefore, it is possible to effectively suppress
traffic congestion.
[0128] Next, a second embodiment of the invention will be
described. As shown in FIG. 16, a vehicle control device 10b
according to this embodiment differs from the vehicle control
device according to the first embodiment in that it does not
include the vehicle-to-vehicle communication device 12 and the
road-to-vehicle communication device 14 and an MM (Multimedia)
communication device 18 is connected to the navigation system 16.
The MM communication device 18 is for receiving information related
to the penetration rate of the system-provided vehicles 100a and
100b transmitted from a predetermined management center.
[0129] In this embodiment, the vehicle control device does not have
a communication function, but the system-provided vehicle having a
vehicle speed and inter-vehicle distance control function, such as
the function of an ACC 30, predicts the percentage of the
system-provided vehicles from information related to the
penetration rate of the system-provided vehicles received by the MM
communication device 18, predicts the number of general vehicles
disposed between the system-provided vehicles on the basis of the
predicted percentage, and adjusts the inter-vehicle distance using
the sum of the inter-vehicle distances as the upper limit,
similarly to the first embodiment. Therefore, in this embodiment,
it is possible to perform vehicle control for preventing traffic
congestion, without a communication function or even in the section
other than the communicable range.
[0130] Next, a third embodiment of the invention will be described.
In this embodiment, vehicle control is performed to uniformly
distribute the vehicles traveling in the lane, thereby preventing
traffic congestion. As shown in FIG. 17, a vehicle control device
10c according to this embodiment is provided in a vehicle and
includes an input unit 50, a calculating unit 60, and a control
unit 70.
[0131] The input unit 50 includes an infrastructure information
receiving system 51, a vehicle-to-vehicle communication system 52,
a vehicle-in-front speed detecting system 53, and a driving lane
recognizing system 54. The infrastructure information receiving
system 51 receives information, such as the average speed of the
road in each lane, the amount of traffic (the number of vehicles
per unit time), and the possibility of traffic congestion
transmitted from, for example, a management center, from an optical
beacon communication device, which is a road infrastructure. The
vehicle-to-vehicle communication system 52 performs
vehicle-to-vehicle communication to transmit or receive information
about the position or speed system-provided vehicles other than the
host vehicle, or information about whether to turn on or off
vehicle control for preventing traffic congestion. Specifically,
the vehicle-in-front speed detecting system 53 is, for example, an
inter-vehicle distance sensor that measures the distance from the
vehicle in front. The traveling lane recognizing system 54 detects
the lane in which the host vehicle travels using an autonomous
sensor, such as a camera.
[0132] The calculating unit 60 includes a traffic flow improvement
control system 61. The traffic flow improvement control system 61
performs control for improving the traffic flow of the road on the
basis of various kinds of information acquired by the input unit
50. The control unit 70 includes an engine control ECU 71 that
controls an engine on the basis of a command signal from the
calculating unit 60, a brake control ECU 72 that controls a brake,
and a steering control ECU 73 that controls steering.
[0133] Next, the operation of the vehicle control device 10c
according to this embodiment will be described. First, as a
premise, a situation in which the vehicle control device 10c
according to this embodiment is applied will be described. As shown
in FIG. 18, it is assumed that the amount of traffic increases
immediately before traffic congestion occurs in a road 500. In this
case, as shown in a portion surrounded by a dashed line in FIG. 18,
the general vehicles 200 that quicken their pace are concentrated
on the driving lane. In this state, when there is a vehicle which
reduces its speed due to, for example, a sag section, traffic
congestion occurs.
[0134] As shown in FIG. 19, statistical data proved that the
traffic capacity of the road increased more effectively when the
vehicles traveled in the low speed range than when the vehicles
traveled at the maximum speed. Therefore, in this embodiment,
traffic congestion is prevented by the following procedure.
[0135] As shown in FIGS. 20 and 23, a system-provided vehicle 100
including the traveling control device 10c recognizes the lane in
which the host vehicle travels using the traveling lane recognizing
system 54 (S101). An optical beacon communication device transmits
the traffic conditions, such as the number of vehicles per unit
time in each lane and the average speed detected by a road
infrastructure 600 and the system-provided vehicle 100 receives the
traffic conditions using the infrastructure information receiving
system 51 (S102). In the example shown in FIG. 23, as shown in a
portion surrounded by a dashed line on the left side of FIG. 23,
the general vehicle changes its lane to the driving lane which is
on the left side in the traveling direction and the vehicles are
concentrated on the driving lane.
[0136] The traffic flow improvement control system 61 of the
calculating unit 60 compares various kinds of information of each
lane acquired by the input unit 50, such as the amount of traffic
.sigma.=as(n) of the lane of the host vehicle, the amount of
traffic .sigma.=ar(n) of other lanes, the average vehicle speed
V=vs(n) of the lane of the host vehicle, and the average vehicle
speed V=vr(n) of other lanes (S103). The traffic flow improvement
control system 61 of the calculating unit 60 determines which of a
region R1 and a region R2 includes the traffic conditions of the
lane of the host vehicle and which of the regions R1 and R2
includes the traffic conditions of other lanes in the map shown in
FIG. 21 (S104). This determination may be performed by the road
infrastructure and the determination result may be transmitted to
the system-provided vehicle 100.
[0137] When other lanes are included in the region R1 and the lane
of the host vehicle is included in the region R2, that is, when the
amount of traffic of the lane of the host vehicle is more than the
amount of traffic of other lane (S105), the traffic flow
improvement control system 61 performs control to reduce the speed
of the host vehicle to an arbitrary set vehicle speed (S106). In
this case, the traffic flow improvement control system 61 reduces
the speed of the host vehicle by a predetermined value V1. The
traffic flow improvement control system 61 sufficiently reduces
acceleration -a1. Alternatively, in this case, the traffic flow
improvement control system 61 may reduce the speed of the host
vehicle by V2 with respect to the average vehicle speed vr(n) of
other lanes. When both the lane of the host vehicle and other lanes
are included in the region R2, the amount of traffic of the lane of
the host vehicle may be more than that of other lanes.
[0138] In this case, as shown in a portion surrounded by a dashed
lie on the right side of FIG. 23, since the speed of the lane of
the host vehicle is reduced and the amount of traffic of another
adjacent lane is less than the amount of traffic of the lane of the
host vehicle, the host vehicle is guided to change its lane to
another adjacent lane. In this case, when the concentration of the
vehicles on the lane of the host vehicle is not removed, the
traffic flow improvement control system 61 reduces the speed of the
host vehicle again.
[0139] When other lanes are included in the region R1 and the lane
of the host vehicle is not included in the region R2, that is, when
the amount of traffic of the lane of the host vehicle is not more
than the amount of traffic of other lanes and the concentration of
the vehicles on the lane of the host vehicle is removed (S107),
during speed reduction control (S108), the traffic flow improvement
control system 61 gradually returns the vehicle speed to an
arbitrary set vehicle speed while detecting the distance from the
vehicle in front using the vehicle-in-front speed detecting system
53 (S109). The reason is that, when the vehicle speeds are
alternately reduced in each lane, the vehicle speed becomes too
low.
[0140] In this case, the traffic flow improvement control system 61
returns the speed of the host vehicle to the value before the speed
reduction control is performed. In addition, in this case, the
traffic flow improvement control system 61 sufficiently reduces
acceleration a2. In addition, the traffic flow improvement control
system 61 increases the speed of the host vehicle by V2 with
respect to the average vehicle speed vr(n) of other lanes.
Alternatively, the traffic flow improvement control system 61 may
set the speed of the host vehicle to be equal to the average
vehicle speed vr(n) of other lanes. As shown in FIG. 22, the
vehicle speeds of the driving lane and the passing lane are
alternately increased and decreased by the above-mentioned control
operation and the concentration of the vehicles on the lane is
removed.
[0141] In addition, a situation in which information cannot be
acquired from the road infrastructure is considered. In this case,
the vehicle tends to move to the lane in which the average speed is
more than that in other lanes. Therefore, it is possible to reduce
the concentration of the vehicles on the lane by sharing
information, which is related to the lane and speed of the vehicles
traveling, between the system-provided vehicles 100 using the
vehicle-to-vehicle communication system 52 and alternately
increasing and decreasing the vehicle speed.
[0142] In this case, as shown in FIG. 24, the system-provided
vehicle 100 provided with the traveling control device 10c
recognizes the lane of the host vehicle using the traveling lane
recognizing system 54 (S201). The system-provided vehicles 100
share the information related to the lane and the vehicle speed
using the vehicle-to-vehicle communication system 52 (S202). In
this case, the traveling control device may acquire data for the
position where traffic congestion occurs, such as a sag section,
from, for example, a navigation system and start control at a
position X.sub.2 km ahead of the sag section, and cancel the
control after the vehicle passes through the sag section.
[0143] The traffic flow improvement control system 61 of the
calculating unit 60 calculates the average vehicle speed V=vs(n) of
the lane of the host vehicle and the average vehicle speed V=vr(n)
of other lanes in the range of X.sub.1 m before and after the host
vehicle on the basis of the information of each lane acquired by
the vehicle-to-vehicle communication system 52 (S203). When
vs(n)>vr(n)+.DELTA.V1 is satisfied, that is, the average vehicle
speed of the lane of the host vehicle is more than the sum of the
average vehicle speed of other lanes and a predetermined threshold
value .DELTA.V1 (S204) and the state is maintained for a unit time
T1 (S205), the traffic flow improvement control system 61 performs
control to reduce the speed of the host vehicle to an arbitrary set
vehicle speed (S206).
[0144] On the other hand, when vs(n)>vr(n)+.DELTA.V1 is not
satisfied, that is, the average vehicle speed of the lane of the
host vehicle is not more than the sum of the average vehicle speed
of other lanes and the predetermined threshold value .DELTA.V1
(S204) and the state is maintained for the unit time T1 (S207), the
traffic flow improvement control system 61 performs control to
increase the speed of the host vehicle to an arbitrary set vehicle
speed (S208).
[0145] As such, in this embodiment, speed control is performed when
the conditions of Step S204 are maintained for the unit time T1. In
this way, after the speed is changed, the vehicle speed is
maintained for the time T1 and then the setting of the vehicle
speed of each lane is changed. In this case, the average vehicle
speed vr of other lanes are set such that the accelerational at
that time is sufficiently reduced. In addition, the set vehicle
speed of each lane may be, for example,
V3=|vs(n)-vr(n)|+.DELTA.v2.
[0146] The amount of traffic on the road is greatly affected by the
concentration of the amount of traffic in each lane. According to
this embodiment, the traffic flow improvement control system 61 of
the calculating unit 60 controls at least one of the inter-vehicle
distance and the vehicle speed on the basis of the amount of
traffic in each lane of the road related to the information
acquired by the input unit 50. Therefore, it is possible to
effectively suppress traffic congestion according to the
concentration of the amount of traffic in each lane.
[0147] The exemplary embodiments of the invention have been
described above, but the invention is not limited to the
above-described embodiments. Various modifications and changes of
the invention can be made. For example, in the above-described
embodiments, the vehicle control device provided in each
system-provided vehicle performs vehicle control for preventing
traffic congestion. However, for example, the vehicle control
device may be provided only in the management center and transmit
commands from the management center to each vehicle using
communication, thereby performing the vehicle control for
preventing traffic congestion.
INDUSTRIAL APPLICABILITY
[0148] According to the invention, it is possible to effectively
suppress traffic congestion when the penetration rate of
system-provided vehicles including the vehicle control device
according to the invention is low.
REFERENCE SIGNS LIST
[0149] 10a, 10b, 10c: VEHICLE CONTROL DEVICE [0150] 12:
VEHICLE-TO-VEHICLE COMMUNICATION DEVICE [0151] 14: ROAD-TO-VEHICLE
COMMUNICATION DEVICE [0152] 16: NAVIGATION SYSTEM [0153] 18: MM
COMMUNICATION DEVICE [0154] 20: ECU [0155] 30: ACC [0156] 32: RADAR
[0157] 50: INPUT UNIT [0158] 51: INFRASTRUCTURE INFORMATION
RECEIVING SYSTEM [0159] 52: VEHICLE-TO-VEHICLE COMMUNICATION SYSTEM
[0160] 53: VEHICLE-IN-FRONT SPEED DETECTING SYSTEM (FOR EXAMPLE,
INTER-VEHICLE DISTANCE SENSOR) [0161] 54: TRAVELING LANE
RECOGNIZING SYSTEM (FOR EXAMPLE, CAMERA) [0162] 60: CALCULATING
UNIT [0163] 61: TRAFFIC FLOW IMPROVEMENT CONTROL SYSTEM [0164] 70:
CONTROL UNIT [0165] 71: ENGINE CONTROL ECU [0166] 72: BRAKE CONTROL
ECU [0167] 73: STEERING CONTROL ECU [0168] 100, 100a, 100b:
SYSTEM-PROVIDED VEHICLE [0169] 200, 200p: GENERAL VEHICLE [0170]
500: ROAD [0171] 600: OPTICAL BEACON COMMUNICATION DEVICE
* * * * *