U.S. patent application number 17/432319 was filed with the patent office on 2022-03-24 for vehicle travel control method and vehicle travel control device.
The applicant listed for this patent is Nissan Motor Co., Ltd., Renault S.A.S.. Invention is credited to Akinobu Gotou, Satoshi Tange.
Application Number | 20220089186 17/432319 |
Document ID | / |
Family ID | 1000006054920 |
Filed Date | 2022-03-24 |
United States Patent
Application |
20220089186 |
Kind Code |
A1 |
Gotou; Akinobu ; et
al. |
March 24, 2022 |
Vehicle Travel Control Method and Vehicle Travel Control Device
Abstract
A travel control method for a vehicle having an autonomous
travel control function includes: detecting an oncoming vehicle
travelling in the opposite lane of the travel lane in which the
subject vehicle travels; predicting whether or not the oncoming
vehicle enters into the travel lane in which the subject vehicle
travels; when it is predicted that the oncoming vehicle enters into
the travel lane in which the subject vehicle travels, setting
initial deceleration of the subject vehicle in a case of time until
the subject vehicle and the oncoming vehicle pass each other being
relatively long to a smaller value than the initial deceleration in
a case of the time being relatively short, and executing
deceleration travel control of the subject vehicle.
Inventors: |
Gotou; Akinobu; (Kanagawa,
JP) ; Tange; Satoshi; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nissan Motor Co., Ltd.
Renault S.A.S. |
Yokohama-shi, Kanagawa
Boulogne-Billancourt |
|
JP
FR |
|
|
Family ID: |
1000006054920 |
Appl. No.: |
17/432319 |
Filed: |
March 1, 2019 |
PCT Filed: |
March 1, 2019 |
PCT NO: |
PCT/IB2019/000293 |
371 Date: |
August 19, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60W 60/0027 20200201;
B60W 60/0015 20200201; B60W 30/0956 20130101; B60W 10/20 20130101;
B60W 2720/103 20130101; B60W 10/18 20130101; B60W 2554/80 20200201;
B60W 2554/4041 20200201 |
International
Class: |
B60W 60/00 20060101
B60W060/00; B60W 30/095 20060101 B60W030/095; B60W 10/20 20060101
B60W010/20; B60W 10/18 20060101 B60W010/18 |
Claims
1. A travel control method for a vehicle having an autonomous
travel control function, comprising: detecting an oncoming vehicle
travelling toward a subject vehicle; predicting whether the
oncoming vehicle enters into a travel lane in which the subject
vehicle travels; when it is predicted that the oncoming vehicle
enters into the travel lane in which the subject vehicle travels,
setting initial deceleration of the subject vehicle in a case of
time until the subject vehicle and the oncoming vehicle pass each
other being relatively long to a smaller value than the initial
deceleration in a case of the time being relatively short; and
executing deceleration travel control of the subject vehicle,
wherein the deceleration travel control of the subject vehicle is
executed at a deceleration start position for starting deceleration
of the subject vehicle not to come into contact with the oncoming
vehicle that is predicted to enter into the travel lane.
2. The travel control method for a vehicle according to claim 1,
comprising: determining the deceleration start position for
starting the deceleration of the subject vehicle so as not to come
into contact with the oncoming vehicle that is predicted to enter
into the travel lane in which the subject vehicle travels;
detecting whether or not the subject vehicle arrives at the
deceleration start position; and executing the deceleration travel
control of the subject vehicle upon the subject vehicle arriving at
the deceleration start position.
3. The travel control method for a vehicle according to claim 2,
comprising: detecting whether or not the subject vehicle arrives at
the deceleration start position; and executing the deceleration
travel control upon the subject vehicle arriving at the
deceleration start position, with the initial deceleration larger
than the initial deceleration in a case that the subject vehicle
does not arrive at the deceleration start position.
4. The travel control method for a vehicle according to claim 2,
comprising: setting a stop position for stopping the subject
vehicle so as not to come into contact with the oncoming vehicle
that is predicted to enter into the travel lane in which the
subject vehicle travels, on a basis of a situation ahead of the
subject vehicle; determining the deceleration start position for
starting the deceleration of the subject vehicle on a basis of the
set stop position, a current position of the subject vehicle,
current vehicle speed of the subject vehicle, predetermined
reference deceleration, and the initial deceleration; detecting
whether or not the subject vehicle arrives at the deceleration
start position; and executing the deceleration travel control of
the subject vehicle upon the subject vehicle arriving at the
deceleration start position.
5. The travel control method for a vehicle according to claim 4,
comprising: setting a target vehicle speed profile for decelerating
the subject vehicle with the predetermined reference deceleration
from the current position; determining a passing position at which
the subject vehicle and the oncoming vehicle pass each other on a
basis of the target vehicle speed profile and vehicle speed of the
oncoming vehicle; and setting the initial deceleration upon
executing the deceleration travel control of the subject vehicle on
a basis of a relative positional relation between the stop position
and the passing position.
6. The travel control method for a vehicle according to claim 4,
comprising: setting the stop position for stopping the subject
vehicle so as not to come into contact with the oncoming vehicle
that is predicted to enter into the travel lane in which the
subject vehicle travels, on a basis of an approach route of the
oncoming vehicle; setting the target vehicle speed profile for
controlling travel of the subject vehicle with the predetermined
reference deceleration while the subject vehicle travels from the
current position to the stop position and stops at the stop
position; determining a passing position at which the subject
vehicle and the oncoming vehicle pass each other, on a basis of the
target vehicle speed profile and vehicle speed of the oncoming
vehicle; and setting the initial deceleration upon executing the
deceleration travel control of the subject vehicle on a basis of a
relative positional relation between the stop position and the
passing position.
7. The travel control method of a vehicle according to claim 5,
comprising: when the passing position is on a subject vehicle side
relative to the stop position, setting the initial deceleration in
a case of a distance between the stop position and the passing
position being relatively large smaller than the predetermined
reference deceleration and the initial deceleration in a case of
the distance being relatively small; and executing the deceleration
travel control of the subject vehicle with the set initial
deceleration.
8. The travel control method for a vehicle according to claim 4,
comprising: switching the set initial deceleration to predetermined
final deceleration at a timing at which the subject vehicle can be
stopped at the stop position when the set initial deceleration is
switched to the predetermined final deceleration, when executing
the deceleration travel control of the subject vehicle with the set
initial deceleration; and executing the deceleration travel control
of the subject vehicle with the predetermined final
deceleration.
9. The travel control method for a vehicle according to claim 4,
comprising: switching the predetermined final deceleration to final
deceleration larger than the predetermined final deceleration when
a distance between the set stop position and the subject vehicle is
a first predetermined distance; and executing the deceleration
travel control of the subject vehicle.
10. The travel control method for a vehicle according to claim 5,
comprising: setting the predetermined reference deceleration to
final deceleration in place of setting the initial deceleration
when the passing position is on an oncoming vehicle side relative
to the stop position; determining whether or not the subject
vehicle can be stopped at the stop position on a basis of the set
final deceleration, the current position of the subject vehicle,
the current vehicle speed of the subject vehicle, and the stop
position; switching the set final deceleration to final
deceleration larger than the set final deceleration when it is
determined that the subject vehicle cannot stop at the stop
position; and executing the deceleration travel control of the
subject vehicle with the set final deceleration or with the final
deceleration larger than the set final deceleration.
11. The travel control method for a vehicle according to claim 1,
wherein the initial deceleration is a predetermined value.
12. The travel control method for a vehicle according to claim 1,
wherein the initial deceleration includes a plurality of initial
deceleration values.
13. The travel control method for a vehicle according to claim 12,
wherein the set initial deceleration finally in terms of time is
the smallest initial deceleration of the plurality of the initial
deceleration values.
14. A travel control method for a vehicle having an autonomous
travel control function, comprising: detecting an oncoming vehicle
travelling toward a subject vehicle; predicting whether or not the
oncoming vehicle enters into a travel lane in which the subject
vehicle travels; when it is predicted that the oncoming vehicle
enters into the travel lane in which the subject vehicle travels,
setting initial deceleration of the subject vehicle in a case of
time until the subject vehicle and the oncoming vehicle pass each
other being relatively long to a smaller value than the initial
deceleration in a case of the time being relatively short; and
executing deceleration travel control of the subject vehicle, the
travel control method further comprising: detecting movement of the
oncoming vehicle while executing the deceleration travel control of
the subject vehicle with the initial deceleration; predicting
whether or not the subject vehicle can travel in the travel lane in
which the subject vehicle travels without coming into contact with
the oncoming vehicle; and setting deceleration smaller than the
initial deceleration while executing the deceleration travel
control when it is predicted that the subject vehicle can travel in
the travel lane in which the subject vehicle travels without coming
into contact with the oncoming vehicle.
15. The travel control method for a vehicle according to claim 1,
comprising: setting the stop position for stopping the subject
vehicle so as not to come into contact with the oncoming vehicle
that is predicted to enter into the travel lane in which the
subject vehicle travels; setting the target vehicle speed profile
for controlling travel of the subject vehicle with predetermined
reference deceleration while the subject vehicle travels from the
current position to the stop position and stops at the stop
position; determining a passing position at which the subject
vehicle and the oncoming vehicle pass each other, on a basis of the
target vehicle speed profile and vehicle speed of the oncoming
vehicle; when the passing position is on a subject vehicle side
relative to the stop position, setting initial speed in a case of a
distance between the stop position and the passing position being
relatively large smaller than a speed conforming to the reference
deceleration in a case of the distance being relatively small; and
executing the travel control of the subject vehicle so that the set
initial speed is achieved.
16. The travel control method for a vehicle according to claim 15,
wherein the initial speed is speed conforming to the smallest
deceleration at the passing position.
17. The travel control method for a vehicle according to claim 1,
comprising: detecting the oncoming vehicle travelling on an
opposite lane of the travel lane in which the subject vehicle
travels; calculating a distance between the subject vehicle and the
oncoming vehicle when the oncoming vehicle is detected; predicting
whether or not the oncoming vehicle enters into the travel lane in
which the subject vehicle travels when the distance is longer than
a second predetermined distance; and when it is predicted that the
oncoming vehicle enters into the travel lane in which the subject
vehicle travels, executing the deceleration travel control of the
subject vehicle with deceleration of the subject vehicle, the
deceleration being set to a smaller value in a case of the time
until the subject vehicle and the oncoming vehicle pass each other
being relatively long than the deceleration in a case of the time
being relatively short.
18. A travel control device for a vehicle comprising a controller,
the controller executing autonomous travel control by controlling
at least one of a steering device, a driving device, and a braking
device in accordance with a travel route of subject vehicle, and
the controller being configured to: detect an oncoming vehicle
travelling toward the subject vehicle; predict whether or not the
oncoming vehicle enters into a travel lane in which the subject
vehicle travels; when it is predicted that the oncoming vehicle
enters into the travel lane in which the subject vehicle travels,
set initial deceleration of the subject vehicle in a case of time
until the subject vehicle and the oncoming vehicle pass each other
being relatively long to a smaller value than the initial
deceleration in a case of the time being relatively short; and
execute deceleration travel control of the subject vehicle, wherein
the deceleration travel control of the subject vehicle is executed
at a deceleration start position for starting deceleration of the
subject vehicle so as not to come into contact with the oncoming
vehicle that is predicted to enter into the travel lane.
Description
TECHNICAL FIELD
[0001] The present invention relates to a travel control method and
a travel control device of a vehicle.
BACKGROUND
[0002] A device for predicting a route of a vehicle is known in
which when an oncoming vehicle (a vehicle traveling toward a
subject vehicle from ahead of the subject vehicle) travelling in an
opposite lane of a subject vehicle overpasses a preceding vehicle
of the oncoming vehicle, at a situation in which the oncoming
vehicle strays from the opposite lane onto a subject lane, whether
the oncoming vehicle overtakes the preceding vehicle is determined,
and when it is determined that the oncoming vehicle overtakes the
preceding vehicle. Then, a realization probability is calculated so
that the realization probability represents a probability of a
route in which a vehicle travels across a lane to an opposite lane
side being realized relatively higher than the realization
probability calculated when it is determined that the oncoming
vehicle does not overtake the preceding vehicle
(JP2010-097261A).
SUMMARY
[0003] The conventional device for predicting the route of the
vehicle has functions for generating a plurality of routes that can
be adopted by the subject vehicle on a basis of subject vehicle
data. The plurality of possible routes include a condition in which
the subject vehicle decelerates or stops in order to wait for
completion of overtake by an overtaking vehicle when a following
vehicle overtakes its preceding vehicle in the opposite lane. Refer
to paragraph of JP2010-097261A.
[0004] However, in the above-mentioned JP2010-097261A, in a
situation in which the oncoming vehicle strays from the opposite
lane onto the subject lane in order to overtake its preceding
vehicle while the subject vehicle travels, contents of travel
control for the subject vehicle to decelerate or stop the subject
vehicle is not disclosed. Now, it supposes that the subject vehicle
decelerates with constant deceleration and waits for that the
oncoming vehicle passes by the subject vehicle. In such cases, when
the passing position with the oncoming vehicle is close to a
current position of the subject vehicle, such as when the oncoming
vehicle finishes overtaking at high-speed contrary to expectations,
the jerk (a derivative value of acceleration or a rate of change in
acceleration per unit time) at the time of switching to
acceleration travel control is increased. This increase of the jerk
discomforts an occupant of the subject vehicle.
[0005] The problem to be solved by the present invention is to
provide the travel control method and the travel control device for
a vehicle that can suppress discomfort of the occupant in the scene
in which the subject vehicle and the oncoming vehicle pass each
other.
[0006] The present invention solves the problem mentioned above by
setting initial deceleration of the subject vehicle in a case of
time until the subject vehicle and the oncoming vehicle pass each
other being relatively long to a smaller value than the initial
deceleration in a case of the time being relatively short, when it
is predicted that the oncoming vehicle travelling in the opposite
lane of the travel lane in which the subject vehicle travels enters
into the travel lane in which the subject vehicle travels; and
executing deceleration travel control of the subject vehicle.
[0007] According to the present invention, when the oncoming
vehicle is predicted to enter into the travel lane of the subject
vehicle, the deceleration travel control is performed with the
relatively small deceleration initially. This allows to secure long
grace time for determining whether to stop or reaccelerate the
subject vehicle. As a result, the jerk can be decreased when it is
determined that reacceleration is performed, and the discomfort of
the occupant can be suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a block diagram illustrating an embodiment of the
travel control device for a vehicle of the present invention;
[0009] FIG. 2A is a flow chart (1/3) illustrating a procedure of a
process in the passing scene executed in the travel control device
for a vehicle shown in FIG. 1;
[0010] FIG. 2B is a flow chart (2/3) illustrating the procedure of
the process in the passing scene executed in the travel control
device for a vehicle shown in FIG. 1;
[0011] FIG. 2C is a flow chart (3/3) illustrating the procedure of
the process in the passing scene executed in the travel control
device for a vehicle shown in FIG. 1;
[0012] FIG. 3 is a plan view illustrating a first example of the
passing scene and a graph illustrating the deceleration profile
corresponding to this scene;
[0013] FIG. 4 is a plan view illustrating a second example of the
passing scene and a graph illustrating the deceleration profile
corresponding to this scene;
[0014] FIG. 5 is a plan view illustrating a third example of the
passing scene and a graph illustrating the deceleration profile
corresponding to this scene;
[0015] FIG. 6 is a plan view illustrating a fourth example of the
passing scene and a graph illustrating the deceleration profile
corresponding to this scene; and
[0016] FIG. 7 is a plan view illustrating a fifth example of the
passing scene and a graph illustrating the deceleration profile
corresponding to this scene.
DETAILED DESCRIPTION
[0017] FIG. 1 is the block diagram illustrating features of the
travel control device for a vehicle VTC according to the present
embodiment. The travel control device is also referred to as a
Vehicle Travel Controller (VTC). FIGS. 3 to 7 are plan views
illustrating examples of the passing scenes, and graphs
illustrating deceleration profiles corresponding to the scenes. The
travel control device for a vehicle VTC of the present embodiment
is also an embodiment of implementing the travel control method for
a vehicle according to the present invention. As shown in FIG. 1,
the travel control device for a vehicle VTC of the present
embodiment includes a radar device 11, a camera 12, a map database
13, a position detecting device 14, a vehicle speed sensor 15, an
oncoming vehicle route predicting unit 21, a subject vehicle route
predicting unit 22, a travelability determination unit 23, a target
vehicle speed generating unit 24, and a vehicle speed track control
unit 25. Incidentally, among the unit and devices as shown in FIG.
1, the drive control device 51, the engine 52, the brake control
device 53 and the brake 54 are components of the vehicle. Further,
the terms of the subject vehicle V1, the oncoming vehicle V2, a
parked vehicle V3, the travel lane L1, the opposite lane L2, a
current position P1 of the subject vehicle V1, a stop position P2
of the subject vehicle V1, a passing position P3, a deceleration
start position P4, and an approach route R of the oncoming vehicle
V2 are related to the travel scenes as shown in FIGS. 3 to 7. The
terms are explained below.
[0018] Among the units comprising the travel control device for a
vehicle VTC, the radar device 11, the camera 12, the position
detecting device 14, and the vehicle speed sensor 15 are composed
of various sensors as described later. The map database 13 is
composed of memories. Also, among the units comprising the travel
control device for a vehicle VTC, the oncoming vehicle route
predicting unit 21, the subject vehicle route predicting unit 22,
the travelability determination unit 23, the target vehicle speed
generating unit 24, and the vehicle speed track control unit 25 are
composed of one or more computers, and software installed in the
computers. The computer comprises a ROM storing a program for
having the respective units such as the oncoming vehicle route
predicting unit 21, the subject vehicle route predicting unit 22,
the travelability determination unit 23, the target vehicle speed
generating unit 24, and the vehicle speed track control unit 25 to
function, a CPU executing the program stored in the ROM, and a RAM
functioning as an accessible storage device. As operation circuits,
an MPU, a DSP, an ASIC, an FPGA, and the like can be used instead
of or together with the CPU.
[0019] The radar device 11 comprises a laser range finder (LRF)
provided at a front portion of the vehicle and/or a radar using a
millimeter wave or an ultrasonic wave. The radar device 11 outputs
information signal on a target or an obstacle to the oncoming
vehicle route predicting unit 21. The laser range finder irradiates
a laser beam, which is an output wave for measuring a distance, to
an area in front of the vehicle, and detects the reflected wave
(detection wave). This generates a ranging signal indicating the
target around the vehicle and a relative position between the
target and the vehicle. The target is, for example, another vehicle
travelling in a travelable road in which the vehicle travels, a
motorcycle, a bicycle, a pedestrian, a lane segment line on a road
surface, a curb at a shoulder of a road, a guardrail, a
wall-surface, a fill, and the like. In addition, the radar using
the millimeter or ultrasonic wave irradiates the millimeter wave or
the ultrasonic wave in front of the vehicle to scan a predetermined
area around the subject vehicle. This allows to detect the obstacle
such as the other vehicle, the motorcycle, the bicycle, the
pedestrian, the curb of the shoulder of the road, the guardrail,
the wall-surface, and the fill that exist around the subject
vehicle. For example, the radar device detects the relative
position (an azimuth direction) between the obstacle and the
subject vehicle, the relative speed of the obstacle, the distance
between the subject vehicle and the obstacle, and the like as a
situation around the subject vehicle.
[0020] The camera 12 is provided in front of the vehicle, rear of
the vehicle and side of the vehicle (i.e., an entire circumference
of the vehicle), and outputs the information signal of the target
and the obstacle to the oncoming vehicle route predicting unit 21
and the subject vehicle route predicting unit 22. The camera 12 is
an image sensor for acquiring image data by capturing a
predetermined area of the front, the rear, or the side of the
subject vehicle, and includes, for example, a CCD wide-angle camera
provided in an upper portion of a front windshield within a vehicle
cabin, in left-side and right-side mirrors, in a trunk lid, and the
like. The camera 12 may be a stereoscopic camera or an
omnidirectional camera and may include a plurality of the image
sensors. The camera 12 detects a road existing ahead of, behind, or
in sides of the subject vehicle and a structure, a road sign, a
signage, the other vehicle, the motorcycle, the bicycle, the
pedestrian, and the like as the situation around the subject
vehicle from the acquired image data.
[0021] The map database 13 stores three-dimensional high-definition
map information. The map database 13 is a memory accessible from
the oncoming vehicle route predicting unit 21 and the subject
vehicle route predicting unit 22. The three-dimensional
high-definition map information stored in the map database 13 is
three-dimensional map information based on a road shape detected
when a vehicle for acquiring data travels on the road actually. The
three-dimensional high-definition map information is map
information to which, together with the map information, detailed
and high-definition positional information such as a merge point of
the road, a branch point, a tollgate, a position at which the
number of lanes decreases, a service area, a parking area and the
like are related as three-dimensional information.
[0022] The position detecting device 14 comprises a GPS unit, a
gyro sensor, and a vehicle speed sensor, and the like. The position
detecting device 14 detects radio waves transmitted from a
plurality of satellite communications by the GPS unit and
periodically acquires positional information of the subject
vehicle. At the same time, the position detecting device 14 detects
the current positional information of the subject vehicle on a
basis of the acquired positional information of the subject
vehicle, angle change information acquired from the gyro sensor,
and vehicle speed acquired from the vehicle speed sensor. The
detected positional information of the subject vehicle is output to
the oncoming vehicle route predicting unit 21 and the subject
vehicle route predicting unit 22.
[0023] The vehicle speed sensor 15 measures rotational speed of a
drivetrain of the vehicle, such as a drive shaft, and detects
travel speed of the subject vehicle on a basis of the measurement
result. Hereinafter, the travel speed is also referred to as
"vehicle speed". The vehicle speed information of the subject
vehicle detected by the vehicle speed sensor 15 is output to the
subject vehicle route predicting unit 22 and the target vehicle
speed generating unit 24.
[0024] The oncoming vehicle route predicting unit 21 acquires a
distance between the subject vehicle and a target around the
subject vehicle output from the radar device 11 and the image data
around the subject vehicle output from the camera 12 at a
predetermined time interval. Thus, the oncoming vehicle route
predicting unit 21 detects whether the other vehicle exists around
the subject vehicle. In addition, the oncoming vehicle route
predicting unit 21 detects whether the detected other vehicle is
the oncoming vehicle travelling in the opposite lane of the travel
lane in which the subject vehicle travels. When the detected other
vehicle is the oncoming vehicle, it is predicted whether the
oncoming vehicle enters into the travel lane in which the subject
vehicle travels. And when it is predicted that the oncoming vehicle
enters into the travel lane in which the subject vehicle travels,
an approach route R of the oncoming vehicle is predicted.
[0025] Functions of the oncoming vehicle route predicting unit 21
are explained on a basis of the travel scene as shown in FIG. 3. In
the travel scene shown in FIG. 3, in a two-lane road that is
left-hand traffic, the subject vehicle V1 travels in the travel
lane L1 to the left of FIG. 3, and the oncoming vehicle V2 travels
in the opposite lane L2 to the right of FIG. 3. In the travel scene
shown in FIG. 3, the parked vehicle V3 is parked ahead of the
oncoming vehicle V2 on the opposite lane L2. For this reason, in
the travel scene shown in FIG. 3, the oncoming vehicle V2 travels
along the approach route R that strays onto the travel lane L1 in
order to overtake the parked vehicle V3.
[0026] In such a travel scene, the oncoming vehicle route
predicting unit 21 of the travel control device VTC mounted on the
subject vehicle V1 detects the existence of the oncoming vehicle V2
and the parked vehicle V3 from the information signal from the
radar device 11 and the camera 12. At the same time, the oncoming
vehicle route predicting unit 21 recognizes the road information
around the subject vehicle V1 by the information signal from the
map database 13 and the position detecting device 14. The oncoming
vehicle route predicting unit 21 recognizes that the subject
vehicle V1 travels in the travel lane L1, the oncoming vehicle V2
travels in the opposite lane L2 toward the subject vehicle V1, and
the parked vehicle V3 is parked on the opposite lane L2 ahead of
the oncoming vehicle V2. At the same time, the oncoming vehicle
route predicting unit 21 detects the vehicle speed of the subject
vehicle V1, the vehicle speed of the oncoming vehicle V2, the
vehicle speed of the parked vehicle V3, the distance between the
subject vehicle V1 and the oncoming vehicle V2, the distance
between the subject vehicle V1 and the parked vehicle V3, and a
trajectory of the oncoming vehicle V2. The trajectory of the
oncoming vehicle V2 is a temporal change of the position of the
oncoming vehicle V2. Note that the oncoming vehicle V2 is not
limited to the vehicle traveling on the opposite lane L2, and
includes the vehicle traveling toward the subject vehicle while
straying from the opposite lane L2.
[0027] With these information signals, the oncoming vehicle route
predicting unit 21 detects whether the other vehicles V2, V3 exist
around the subject vehicle V1. Next, it is detected whether the
detected other vehicles V2, V3 are the oncoming vehicle V2 that
travels in the opposite lane L2 of the travel lane L1 in which the
subject vehicle V1 travels. When the detected other vehicles V2, V3
are the oncoming vehicle V2, it is predicted whether the oncoming
vehicle V2 enters into the travel lane L1 in which the subject
vehicle V1 travels. When the oncoming vehicle V2 is predicted to
enter into the travel lane L1 in which the subject vehicle V1
travels, such as to avoid the parked vehicle V3, the approach route
R is also predicted.
[0028] Note that whether the oncoming vehicle V2 enters into the
travel lane L1 in which the subject vehicle V1 travels can be
predicted on a basis of conditions such as whether the trajectory
of the oncoming vehicle V2 heads to the travel lane L1 in which the
subject vehicle V1 travels, the trajectory of the oncoming vehicle
V2 being determined by temporal change of the position of the
oncoming vehicle V2, or whether the parked vehicle V3 exists in the
opposite lane L2, whether the oncoming vehicle V2 is sufficiently
close to the parked vehicle V3 as compared to the distance between
the subject vehicle V1 and the parked vehicle V3, and whether the
oncoming vehicle V2 is in the situation to be able to overtake the
parked vehicle V3 with sufficient time. The approach route R of the
oncoming vehicle V2 can be predicted on a basis of conditions of
the position and the vehicle speed of the oncoming vehicle V2, the
road shape of the opposite lane L2 and the travel lane L1, and the
position and the shape (size) of the parked vehicle V3.
[0029] As described above, the oncoming vehicle route predicting
unit 21 acquires the current position, the vehicle speed, and the
approach route R of the oncoming vehicle V2 entering into the
travel lane L1 in which the subject vehicle V1 travels. The
oncoming vehicle route predicting unit 21 outputs these information
signals to the travelability determination unit 23 at the
predetermined time interval. The current position, the vehicle
speed, and the approach route R of the oncoming vehicle V2 entering
into the travel lane L1 in which the subject vehicle V1 travels
change from time to time as travel time of the subject vehicle V1
elapses. Therefore, the oncoming vehicle route predicting unit 21
repeats the calculation at the predetermined time interval, and
outputs them to the travelability determination unit 23.
[0030] The subject vehicle route predicting unit 22 generates a
travel route corresponding to the destination that is input in
advance by the driver. The subject vehicle route predicting unit 22
recognizes the current position of the subject vehicle V1 by the
information signal from the position detecting device 14 in order
to drive the subject vehicle V1 along the travel route. The subject
vehicle route predicting unit 22 recognizes the travel lane L1 of
the subject vehicle V1 by the information signal from the map
database 13. Further, the subject vehicle route predicting unit 22
recognizes the vehicle speed of the subject vehicle V1 by the
information signal from the vehicle speed sensor 15. Then, the
subject vehicle route predicting unit 22 acquires the information
signal on the target and the obstacle around the subject vehicle V1
from the camera 12 at the predetermined time interval. As a result,
the subject vehicle V1 travels along the travel lane L1. At the
same time, in order to comply with the Road Acts, the subject
vehicle route predicting unit 22 executes speed control
corresponding to the target such as a traffic light, a crosswalk,
or a stop sign when they are detected. In addition, when the
obstacle such as the pedestrian or the other vehicle is detected by
the camera 12, the speed control or trajectory control is executed
to avoid the contact with the obstacle. The subject vehicle route
predicting unit 22 determines the travel route, the current
position, and the vehicle speed of the subject vehicle V1 as
described above. Then, the subject vehicle route predicting unit 22
outputs these information signals to the travelability
determination unit 23 at the predetermined time interval. The
travel route, the current position, and the vehicle speed of the
subject vehicle V1 change from time to time as the travel time of
the subject vehicle V1 elapses. Therefore, the subject vehicle
route predicting unit 22 repeats the calculation at the
predetermined time interval, and outputs them to the travelability
determination unit 23.
[0031] First, the travelability determination unit 23 determines
whether the subject vehicle V1 comes into contact with the oncoming
vehicle V2 when the subject vehicle V1 travels at the current speed
without the deceleration. That is, the travelability determination
unit 23 determines whether the subject vehicle V1 and the oncoming
vehicle V2 can pass each other without comes into contact with each
other in the travel scene as shown in FIG. 3, on a basis of the
current position, the vehicle speed and the approach route R of the
oncoming vehicle V2 output from the oncoming vehicle route
predicting unit 21 and the travel route, the current position and
the vehicle speed of the subject vehicle V1 output from the subject
vehicle route predicting unit 22.
[0032] In this determination, the travelability determination unit
23 sets the stop position P2 of the subject vehicle V1 from the
approach route R of the oncoming vehicle V2. In the travel scene
shown in FIG. 3, the approach route R of the oncoming vehicle V2 is
predicted by the oncoming vehicle route predicting unit 21. And the
stop position of the subject vehicle V1 that does not come into
contact with the oncoming vehicle V2 traveling along the approach
route R is set. Specifically, as shown in FIG. 3, the position
before the oncoming vehicle V2 changes lanes to return from the
travel lane L1 into which the oncoming vehicle V2 entered to the
original opposite lane L2 is set to the stop position P2 of the
subject vehicle V1. The stop position P2 can be set only by the
approach route R of the oncoming vehicle V2 regardless of the
current position or the vehicle speed of the subject vehicle V1.
Alternatively, the stop position P2 may be set to the position
predetermined distance away from the parked vehicle V3 on a basis
of, for example, the position of the parked vehicle V3 of the
opposite lane L2.
[0033] In the travel scene shown in FIG. 3, it is assumed that the
distance between the current position of the subject vehicle V1 and
the oncoming vehicle V2 is detected to be L, the vehicle speed of
the subject vehicle V1 is detected to be v1, and the vehicle speed
of the oncoming vehicle V2 is detected to be v2. In this case,
since the time t until the two vehicles encounter (come into
contact) is L/(v1+v2), the encounter position is the position at
which the subject vehicle V1 travels from the current position P1
by Lv1/(v1+v2). When the encounter position is a near side (closer
to the subject vehicle V1) relative to the stop position P2 as
shown in FIG. 3, or when it is a far side of the parked vehicle V3,
at the present time, it is determined that the subject vehicle V1
can pass by the oncoming vehicle V2 without coming into contact
with the oncoming vehicle V2 even when the subject vehicle V1
travels at the current speed without the deceleration. In this
case, the information signal of "passable" is output to the target
vehicle speed generating unit 24, and the previous speed control is
continued.
[0034] On the other hand, the travelability determination unit 23
executes the deceleration control when it is determined that the
subject vehicle V1 comes into contact with the oncoming vehicle V2
when the subject vehicle V1 travels at the current speed without
the deceleration. In other words, the travelability determination
unit 23 sets the target vehicle speed profile for controlling the
travel with the predetermined reference deceleration .alpha. in
order to execute the deceleration control for stopping the subject
vehicle V1 at the stop position P2. Next, the travelability
determination unit 23 calculates the passing position P3 at which
the subject vehicle V1 and the oncoming vehicle V2 pass each other
on a basis of the target vehicle speed profile and the vehicle
speed of the oncoming vehicle V2. Then, the travelability
determination unit 23 outputs to the target vehicle speed
generating unit 24 at the predetermined time interval whether the
subject vehicle V1 and the oncoming vehicle V2 can pass each other,
the distance between the current position of the subject vehicle V1
to the stop position, the passing position P3 at which the subject
vehicle V1 and the oncoming vehicle V2 pass each other, and the
deceleration start position P4.
[0035] The deceleration start position P4 and the passing position
P3 can be determined as follows. In the travel scene shown in FIG.
3, the stop position P2 of the subject vehicle V1 is set on a basis
of the approach route R of the oncoming vehicle V2. First, the
predetermined reference deceleration .alpha. that can be stop at
the stop position P2 is set. For example, the .alpha. is set to
between 1.0 and 1.4 m/s.sup.2, the gentler deceleration that does
not discomfort the occupant. The vehicle speed curve using the
.alpha. is shown in FIG. 3 as a parabola of the target speed
profile. The intersection of the straight line representing the
current vehicle speed of the subject vehicle V1 and the parabola of
the target speed profile is determined as the deceleration start
position P4 of the subject vehicle V1. When the subject vehicle V1
travels while maintaining the current vehicle speed and starts the
deceleration in accordance with the reference deceleration .alpha.
of the target speed profile at the deceleration start position P4,
the subject vehicle V1 is decelerated at the speed in accordance
with the target speed profile and is stopped at the stop position
P2. The passing position P3 at which the subject vehicle V1 and the
oncoming vehicle V2 pass each other is calculated from the target
speed profile and the vehicle speed of the oncoming vehicle V2 at
this time.
[0036] When the passing position P3 is located in the near side
(closer to the subject vehicle V1) relative to the stop position P2
as shown in FIGS. 3 to 5, it is determined that at the present
time, the subject vehicle V1 can pass by the oncoming vehicle V2
without comes into contact with the oncoming vehicle V2 so long as
the subject vehicle V1 travels at the speed in accordance with the
target speed profile. On the other hand, when the passing position
P3 is located in the far side relative to the stop position P2 as
shown in FIG. 6, it is determined that, at the present time, the
subject vehicle V1 comes into contact with the oncoming vehicle V2
even when the subject vehicle V1 travels at the speed in accordance
with the target speed profile. When the passing position P3 is
located in the near side relative to the stop position P2 as shown
in FIGS. 3 to 5, the travelability determination unit 23 outputs
the information signal of "passable when decelerated with the
reference deceleration .alpha." to the target vehicle speed
generating unit 24. On the other hand, when the passing position P3
is located in the far side relative to the stop position P2 as
shown in FIG. 6, the information signal of "impassable even when
decelerated with the reference deceleration .alpha." is output to
the target vehicle speed generating unit 24. At the same time, the
travelability determination unit 23 outputs the distance between
the current position to the stop position of the subject vehicle
V1, the passing position P3 at which the subject vehicle V1 and the
oncoming vehicle V2 pass each other, and the deceleration start
position P4 to the target vehicle speed generating unit 24.
[0037] The target vehicle speed generating unit 24 acquires the
travelability determination, the deceleration start position P4,
the passing position P3, and the distance to the stop position P2
from the travelability determination unit 23, and the vehicle speed
of the subject vehicle V1 from the vehicle speed sensor 15 at the
predetermined time interval. In addition, the target vehicle speed
generating unit 24 calculates and sets initial deceleration at an
early stage when the subject vehicle V1 shifts to the deceleration
control. Together with this, the target vehicle speed generating
unit 24 sets final deceleration from the end point of the
deceleration control with the initial deceleration to the point at
which the deceleration control finally finishes. Then, the target
vehicle speed generating unit 24 outputs the set initial
deceleration .alpha.1 and the set final deceleration .alpha.2 to
the vehicle speed track control unit 25.
[0038] The initial deceleration setting unit 241 calculates the
initial deceleration at the early stage when the subject vehicle V1
shifts to the deceleration control. The final deceleration setting
unit 242 calculates the final deceleration from the end point of
the deceleration control with the initial deceleration to the point
at which the deceleration control finally finishes. Note that,
depending on the travel scene, the initial deceleration may
substitute for the final deceleration.
[0039] That is, the target vehicle speed generating unit 24 sets
the deceleration profile in which the deceleration between the
deceleration start position P4 and the stop position P2 becomes
smaller (including that the deceleration is 0) as the time until
the subject vehicle V1 passes by the oncoming vehicle V2 becomes
longer, compared to the case in which the time to pass each other
is shorter. The target vehicle speed generating unit 24 executes
the deceleration control with the deceleration in accordance with
the deceleration profile. In other words, the initial deceleration
.alpha.1 at the deceleration start position P4 is set to the
smaller deceleration than the final deceleration .alpha.2
immediately before the stop position P2. In other words, in place
of setting the deceleration between the deceleration start position
P4 and the stop position P2 to the constant deceleration, a
plurality of different deceleration values is set, and the
plurality of the different deceleration values is set smaller as
the position of the subject vehicle V1 becomes closer to the
deceleration start position P4 (i.e., as the elapsed time since the
deceleration starts is shorter).
[0040] In the travel scene shown in FIG. 3, the initial
deceleration setting unit 241 of the target vehicle speed
generating unit 24 sets the initial deceleration .alpha.1 between
the deceleration start position P4 and the point at which the
deceleration is switched to the value smaller than the deceleration
.alpha. of the target speed profile with respect to the
deceleration .alpha. of the target speed profile (i.e., .alpha. is
larger than .alpha.1, and the absolute value of the slope of the
graph shown is small). The final deceleration setting unit 242 of
the target vehicle speed generating unit 24 sets the final
deceleration .alpha.2 between the position at which the
deceleration is switched to the stop position P2 larger than the
initial deceleration .alpha.1, and larger than the deceleration
.alpha. of the target speed profile (i.e., .alpha.2 is larger than
.alpha., and .alpha. is larger than .alpha.1, and the absolute
value of the slope of the graph shown is larger).
[0041] Further, the initial deceleration setting unit 241 of the
target vehicle speed generating unit 24 can set a fixed value
determined in advance as the initial deceleration .alpha.1 when
setting the initial deceleration .alpha.1. The fixed value is, for
example, 0 to 0.7 m/s.sup.2 with respect to the reference
deceleration of 1.0 to 1.4 m/s.sup.2. In addition, the fixed value
may be a value corresponding to the distance between the passing
position P3 and the stop position P2. The travel scenes shown in
FIG. 4 and FIG. 5 indicate scenes in which the respective distances
between the passing position P3 and the stop position P2 determined
by the travelability determination unit 23 are different. The
distance between the passing position P3 and the stop position P2
in the travel scene shown in FIG. 4 is larger than the distance
between the passing position P3 and the stop position P2 in the
travel scene shown in FIG. 5. Further, the initial deceleration
setting unit 241 of the target vehicle speed generating unit 24
sets the smaller initial deceleration as the distance between the
stop position P2 and the passing position P3 is larger (FIG. 4)
compared to the case in which the distance between the stop
position P2 and the passing position P3 is smaller (FIG. 5).
[0042] That is, the absolute value of the slope of the initial
deceleration in FIG. 4 is set to be smaller than the absolute value
of the slope of the initial deceleration in FIG. 5. That the
distance between the stop position P2 and the passing position P3
is larger means that the position at which the subject vehicle V1
and the oncoming vehicle V2 pass each other is located in the near
side relative to the stop position P2 when decelerated with the
reference deceleration. Therefore, it is highly likely that the
oncoming vehicle V2 returns to the original opposite lane L2 after
the relatively short, elapsed time. Therefore, by setting the small
initial deceleration, the subsequent movement of the oncoming
vehicle V2 can be observed, and the unnecessary deceleration can be
suppressed.
[0043] The initial deceleration .alpha.1 may comprise a plurality
of initial deceleration values .alpha.11, .alpha.12, . . . . In
this case, the last initial deceleration, i.e., the initial
deceleration just before switching to the final deceleration, is
preferably set to the smallest initial deceleration of the
plurality of the initial deceleration values. This is because
setting the last initial deceleration to the smallest deceleration
decreases the jerk when transitioning from the deceleration travel
control to the reacceleration travel control.
[0044] The final deceleration setting unit 242 of the target
vehicle speed generating unit 24 sets the deceleration with which
the subject vehicle V1 can be stopped at the stop position P2 on a
basis of the initial deceleration .alpha.1, the timing of switching
from the initial deceleration .alpha.1, and the distance to the
stop position P2. For example, the final deceleration .alpha.2 may
be the predetermined fixed value within the deceleration limits at
which the occupant is not discomforted. The fixed values may be,
for example, 1.8 to 2.2 m/s.sup.2 with respect to the reference
deceleration 1.0 to 1.4 m/s.sup.2. In the travel scene shown in
FIG. 3, the final deceleration .alpha.2 that is the predetermined
fixed value is set so that the subject vehicle V1 is stopped at the
stop position P2. The intersection of the speed profile in
accordance with the final deceleration .alpha.2 and the initial
deceleration .alpha.1 is defined as the switch position (the switch
timing) to switch from the initial deceleration .alpha.1 to the
final deceleration .alpha.2. Note that, the final deceleration
.alpha.2 may include a plurality of final deceleration values
.alpha.21, .alpha.22 . . . .
[0045] When it is determined that the subject vehicle V1 can be
stopped at the stop position P2 with the predetermined final
deceleration, the deceleration travel control continues with the
final deceleration. On the other hand, when it is determined that
the subject vehicle V1 cannot stop at the stop position P2 with the
predetermined final deceleration (e.g., when the vehicle speed of
the oncoming vehicle V2 decreased and the passing position P3
unexpectedly moves toward the stop position P2), the final
deceleration setting unit 242 prioritizes the stop control of the
subject vehicle V1 and resets the final deceleration larger than
the predetermined final deceleration.
[0046] When the passing position P3 between the subject vehicle V1
and the oncoming vehicle V2 is on the oncoming vehicle V2 side
relative to the stop position P2 as shown in FIG. 6 (e.g., when the
oncoming vehicle V2 suddenly enters into the travel lane L1), the
initial deceleration setting unit 241 and the final deceleration
setting unit 242 of the target vehicle speed generating unit 24 set
the reference deceleration .alpha. to the final deceleration in
place of setting the initial deceleration .alpha.1. It is
determined whether the subject vehicle V1 can be stopped at the
stop position P2 on a basis of the set final deceleration .alpha.,
the current position P1 of the subject vehicle V1, the current
vehicle speed of the subject vehicle V1 and the stop position P2.
When it is determined that the subject vehicle V1 can be stopped at
the stop position P2, the reference deceleration .alpha. is set to
the final deceleration .alpha.2. On the other hand, when it is
determined that the subject vehicle V1 cannot stop at the stop
position P2 with the reference deceleration .alpha., the stop
control of the subject vehicle V1 is prioritized, and the final
deceleration .alpha.2 larger than the reference deceleration
.alpha. is set.
[0047] The vehicle speed track control unit 25 acquires the initial
deceleration .alpha.1 and the final deceleration .alpha.2 generated
by the initial deceleration setting unit 241 and the final
deceleration setting unit 242 of the target vehicle speed
generating unit 24. The vehicle speed track control unit 25
generates the vehicle speed of the subject vehicle V1 in accordance
with the current position of the subject vehicle V1. The vehicle
speed track control unit 25 outputs the information signal to the
drive control device 51 and the brake control device 53 provided in
the vehicle controller of the subject vehicle V1.
[0048] The subject vehicle V1 comprises the engine 52 that is drive
source, and the brake 54 that is brake source. The engine 52 is
controlled by the drive control device 51. The brake 54 (the brake
booster) is controlled by the brake control device 53. Then, the
vehicle speed signal from the vehicle speed track control unit 25
is input to each of the drive control device 51 and the brake
control device 53. Thus, the acceleration travel control, the
constant speed travel control, or the deceleration travel control
of the subject vehicle V1 is executed. Note that the vehicle of the
present invention is not particularly limited. The vehicle includes
electric vehicles (including fuel-cell vehicles) powered by motors
as the drive source, hybrid vehicles comprising both of the engine
and the motor, in addition to engine vehicles powered by the
gasoline engines or the diesel engines as the drive source.
[0049] In the following, a control flow of the travel control
device VTC of the present embodiment is described. The flow charts
shown in FIG. 2A and FIG. 2B illustrate the procedure of the
process in the passing scene executed by the travel control device
VTC shown in FIG. 1. The flow charts are executed at the
predetermined time intervals.
[0050] In the step S1 of the subroutine, the subject vehicle V1 is
assumed to autonomously travel toward the destination by the
autonomous travel function. In the step S2, during the autonomous
travel of the subject vehicle V1, the oncoming vehicle route
predicting unit 21 of the travel control device VTC detects whether
the oncoming vehicle V2 travelling in the opposite lane L2 of the
subject vehicle V1 exists by the radar device 11 and the camera 12.
When the oncoming vehicle V2 travelling in the opposite lane L2
exists, in the step S3, it is predicted whether the oncoming
vehicle V2 enters into the travel lane L1 in which the subject
vehicle V1 travels. When the oncoming vehicle V2 is not detected in
the step S2, and even the oncoming vehicle V2 exists, when it is
predicted that the oncoming vehicle V2 does not enter into the
travel lane L1 in which the subject vehicle V1 travels in the step
S3, the process returns to the step S1 and the autonomous travel is
continued. Note that when the oncoming vehicle V2 is detected in
the step S2, the distance between the subject vehicle V1 and the
oncoming vehicle V2 may also detected, and when the distance is
shorter than the predetermined distance, the deceleration control
of the subject vehicle V1 may be executed at the large deceleration
corresponding to the emergency brake.
[0051] In the step S3, when it is predicted that the oncoming
vehicle V2 enters into the travel lane L1 in which the subject
vehicle V1 travels, the process proceeds to the step S4. In the
step S4, the travelability determination unit 23 determines whether
the subject vehicle V1 can pass by the oncoming vehicle V2 without
coming into contact with the oncoming vehicle V2 in the case that
the subject vehicle V1 travels at the current vehicle speed, on the
basis of the current position of the subject vehicle speed V1, the
vehicle speed of the subject vehicle V1, the current position of
the oncoming vehicle V2, and the vehicle speed of the oncoming
vehicle V2. When it is determined that the subject vehicle V1 and
the oncoming vehicle V2 cannot pass each other without coming into
contact with each other, the process proceeds to the step S5. In
the step S4, when it is determined that the subject vehicle V1 and
the oncoming vehicle V2 can pass each other, the process returns to
the step S1, and the autonomous travel is continued.
[0052] In the step S4, when it is determined that the subject
vehicle V1 cannot pass by the oncoming vehicle V2 unless the
subject vehicle V1 decelerates, in the step S5, the travelability
determination unit 23 acquires the current position of the subject
vehicle V1, the vehicle speed of the subject vehicle V1, the
current position of the oncoming vehicle V2, and the vehicle speed
of the oncoming vehicle V2. Then, in the step S6, the travelability
determination unit 23 predicts the approach route R of the oncoming
vehicle V2. Since the approach route R of the oncoming vehicle V2
is generated by the oncoming vehicle route predicting unit 21, the
approach route R is output to the travelability determination unit
23 in addition to the current position of the subject vehicle V1,
the vehicle speed of the subject vehicle V1, the current position
of the oncoming vehicle V2, and the vehicle speed of the oncoming
vehicle V2.
[0053] In the step S7, the travelability determination unit 23 sets
the stop position P2 of the subject vehicle V1 using the approach
route R of the oncoming vehicle V2. Subsequently, in the step S8,
the travelability determination unit 23 sets the target vehicle
speed profile for controlling the travel with the predetermined
reference deceleration .alpha.. The travelability determination
unit 23 calculates the passing position P3 at which the subject
vehicle V1 and the oncoming vehicle V2 pass each other using the
target vehicle speed profile and the vehicle speed of the oncoming
vehicle V2.
[0054] The calculation of the passing position P3 is explained in
the following. In the travel scene shown in FIG. 3, the stop
position P2 of the subject vehicle V1 is set on the basis of the
approach route R of the oncoming vehicle V2. A bottom (an extreme
value) of the parabola shown in FIG. 3 is adjusted to the stop
position P2 so that the vehicle speed of the subject vehicle V1
becomes 0 at the stop position P2. The parabola assumes that the
target speed profile in which the deceleration .alpha. is constant.
In the step S9, the intersection of the straight line representing
the current vehicle speed of the subject vehicle V1 and the
parabola of the target speed profile is determined as the
deceleration start position P4 of the subject vehicle V1. When the
subject vehicle V1 travels while maintaining the current vehicle
speed and starts deceleration in accordance with the reference
deceleration .alpha. of the target speed profile at the
deceleration start position P4, the subject vehicle V1 decreases
the speed in accordance with the target speed profile and stops at
the stop position P2. The passing position P3 at which the subject
vehicle V1 and the oncoming vehicle V2 pass each other is
calculated using the target speed profile and the vehicle speed of
the oncoming vehicle V2 at this time.
[0055] Once the passing position P3 and the deceleration start
position P4 are calculated, in the step S10, it is determined
whether the passing position P3 is on the near side (the subject
vehicle side) or the far side relative to the stop position P2.
When the passing position P3 is on the near side, the process
proceeds to the step S11. When the passing position P 3 is on the
far side relative to the stop position P2, the process proceeds to
the step S16 in FIG. 2B.
[0056] When the calculated the passing position P3 is on the near
side relative to the stop position P2, the initial deceleration
.alpha.1 is set in the step S11. That is, the initial deceleration
.alpha.1 at the deceleration start position P4 is set to the
smaller deceleration than the final deceleration .alpha.2
immediately before the stop position P2. In other words, in place
of setting the deceleration between the deceleration start position
P4 and the stop position P2 constant, a plurality of different
deceleration values is set. In addition, the plurality of different
deceleration values is set to become smaller with approaching the
deceleration start position P4 (i.e., as the elapsed time since the
deceleration starts is shorter). Further, as shown in FIG. 4 and
FIG. 5, in setting the initial deceleration .alpha.1, the larger
the distance between the stop position P2 and the passing position
P3 is (FIG. 4), the smaller the initial deceleration may be set,
compared to the case in which the distance between the stop
position P2 and the passing position P3 is smaller (FIG. 5).
[0057] Once the initial deceleration .alpha.1 is set, in the step
S12, it is determined whether the current position P1 of the
subject vehicle V1 arrives at the deceleration start position P4.
When the current position P1 of the subject vehicle V1 arrives at
the deceleration start position P4, the deceleration is started as
described in the step S13. The step S12 is repeated until the
current position P1 of the subject vehicle V1 arrives at the
deceleration start position P4. Note that, when the subject vehicle
it is determined 1 does not arrive at the deceleration start
position P4, the acceleration travel control may be executed, the
deceleration travel control may not be executed, the constant speed
travel control may be executed, or the subject vehicle may be
coasted by lifting a throttle and without stepping the brake. In
the process for starting the deceleration in the step S13, the
target vehicle speed is output from the vehicle speed track control
unit 25 to the drive control device 51 and the brake control device
53. Along with the drive control device 51 controls the engine 52,
the brake control device 53 controls the brake 54, so that the
process is executed.
[0058] In the step S14, it is determined whether the subject
vehicle V1 can pass by the oncoming vehicle V2 without coming into
contact with the oncoming vehicle V2 on the basis of the current
position P1 of the subject vehicle V1, the vehicle speed of the
subject vehicle V1, the current position of the oncoming vehicle
V2, and the vehicle speed of the oncoming vehicle V2. That is, in
the step S13, the deceleration of the subject vehicle V1 with the
initial deceleration al starts and the travel situation of the
oncoming vehicle V2 and the like after the deceleration is
detected. When it is determined that the subject vehicle V1 can
pass by the oncoming vehicle V2 without coming into contact with
each other, the process proceeds to the step S15. In the step S15,
the deceleration is terminated, and the process returns to the
autonomous travel control in the step S1. FIG. 7 is the diagram
illustrating the scene in which the determination is made to
proceed from the step S14 to the step S15 at the travelability
determination point with respect to the subject vehicle V1 that
starts the deceleration from the deceleration start position P4
with the initial deceleration .alpha.1. The subject vehicle V1
returns to the autonomous travel control of the step S1, whereby
the return to the set speed is achieved by the reacceleration
indicated by the dotted line in FIG. 7. At this time, the jerk
between the vehicle speed decelerated with the initial deceleration
.alpha.1 and the vehicle speed after the return becomes smaller as
the initial deceleration .alpha.1 is smaller. That is, when
decelerating with the deceleration .alpha. indicated in the target
speed profile of FIG. 7, the jerk between the vehicle speed at the
travelability determination point and the vehicle speed after the
return increases in accordance with the difference of speed as
shown in the figure.
[0059] When it is determined in the step S14 that the subject
vehicle V1 cannot pass by the oncoming vehicle V2 without coming
into contact with the oncoming vehicle V2, the process proceeds to
the step S16. In the steps S16 to S18, the switch position (the
switch timing) is calculated from the currently set initial
deceleration .alpha.1 to the next set final deceleration .alpha.2.
At the same time, it is determined whether the subject vehicle
arrives at the switch position. That is, in the step S16, the final
deceleration setting unit 242 of the target vehicle speed
generating unit 24 sets the final deceleration .alpha.2 with which
the subject vehicle V1 can be stopped at the stop position P2, on
the basis of the initial deceleration .alpha.1, the switch timing
from the initial deceleration .alpha.1, and the distance to the
stop position P2. For example, in the travel scene shown in FIG. 3,
the final deceleration .alpha.2 that is the predetermined fixed
value is set so that the subject vehicle V1 stops at the stop
position P2. The intersection of the speed profile in accordance
with the final deceleration .alpha.2 and the initial deceleration
.alpha.1 is defined as the switch position (the switch timing) from
the initial deceleration .alpha.1 to the final deceleration
.alpha.2. Then, in the step S17, it is determined whether the
subject vehicle V1 arrives at the switch position (the switch
timing). In the step S18, at the timing at which it is determined
that the subject vehicle V1 arrives at the switch position, the
deceleration is switched from the initial deceleration .alpha.1 to
the final deceleration .alpha.2.
[0060] Note that, in the step S10 of FIG. 2A, when the passing
position P3 at which the subject vehicle V1 and the oncoming
vehicle V2 pass each other is on the far side relative to the stop
position P2 as shown in FIG. 6, the process proceeds from the step
S10 to the step S18. In place of setting the initial deceleration
.alpha.1, the deceleration control with the final deceleration
.alpha.2 starts from the deceleration start position P4, as shown
in FIG. 6. This allows the subject vehicle V1 to prevent from
coming into contact with the oncoming vehicle V2.
[0061] In the step S18 described above, the deceleration is
switched to the deceleration with the final deceleration .alpha.2,
and the subject vehicle V1 shifts to the travel control for
stopping at the stop position P2. In the step S19, it is determined
whether the subject vehicle V1 can be stopped at the stop position
P2 on the basis of the current position P1 of the subject vehicle
V1, the vehicle speed of the subject vehicle V1, and the distance
to the stop position P2. When it is determined that the subject
vehicle V1 can be stopped at the stop position P2, the process
proceeds to the step S21 of FIG. 2C. On the other hand, when it is
determined that the subject vehicle V1 cannot stop at the stop
position P2, the process proceeds to the step S19. In the step S19,
the final deceleration .alpha.2 is set again that is acquired by
increasing the value of the currently set final deceleration
.alpha.2. Then, the process returns to the step S18 while executing
the deceleration control with the final deceleration .alpha.2. By
adjusting the final deceleration .alpha.2, the subject vehicle V1
can be surely stopped at the stop position P2.
[0062] In the step S21 of FIG. 2C, it is determined whether the
subject vehicle V1 can pass by the oncoming vehicle V2 without
coming into contact with the oncoming vehicle V2 on the basis of
the current position P1 of the subject vehicle V1, the vehicle
speed of the subject vehicle V1, the current position of the
oncoming vehicle V2 and the vehicle speed of the oncoming vehicle
V2. That is, in the step S18, the deceleration of the subject
vehicle V1 is switched to the deceleration with the final
deceleration .alpha.2, and the subsequent travel situation of the
oncoming vehicle V2 is detected. When it is determined that the
subject vehicle V1 and the oncoming vehicle V2 can pass each other
without coming into contact with each other, the process proceeds
to the step S22. In the step S22, the deceleration is terminated,
and the process returns to the autonomous travel control of the
step S1. As a result, the subject vehicle V1 reaccelerates and
returns to the vehicle speed set by the autonomous travel control.
Note that, in the step S22, when returning to the autonomous travel
control of the step S1 by terminating the deceleration, the target
vehicle speed that conforms to the deceleration smaller than the
initial deceleration is generated, there is no need to decrease the
deceleration in all the sections from the position at which the
deceleration control is stopped to the passing position.
[0063] On the other hand, when it is determined in the step S21
that the subject vehicle V1 cannot pass by the oncoming vehicle V2
without coming into contact with the oncoming vehicle V2, the
process proceeds to the step S23. In the step S23, the deceleration
with the final deceleration .alpha.2 is continued until the subject
vehicle arrives at the stop position P2.
[0064] As stated above, according to the travel control device and
the travel control method of the present embodiment, when the
oncoming vehicle V2 is predicted to enter into the travel lane L1
in which the subject vehicle V1 travels, the initial deceleration
of the subject vehicle V1 in the case of time until the subject
vehicle V1 and the oncoming vehicle V2 pass each other being
relatively long is set to the smaller value than the initial
deceleration in the case of the time being relatively short. As an
example, the subject vehicle V1 is decelerated with the
deceleration in accordance with the deceleration profile that is
indicated by the thick line in FIG. 3. This ensures the grace time
for making the determination on the travel control of the subject
vehicle V1, such as whether to stop or accelerate the subject
vehicle V1. In other words, the travel control of the subject
vehicle V1 can be executed in response to the behavior of the
oncoming vehicle V2 in the grace time. Therefore, it is possible to
suppress the unnecessary stop or the unnecessary acceleration. As a
result, the discomfort of the occupant can be suppressed.
[0065] In particular, in the travel scene of the present embodiment
in which the subject vehicle V1 decelerates in accordance with the
oncoming vehicle V2, even when it is initially determined that the
deceleration is necessary, since there are various changes in the
behaviors, for example, the deceleration or stop of the oncoming
vehicle V2 or the acceleration of the oncoming vehicle V2 to
overtake the parked vehicle, there is a high possibility that the
deceleration is not necessary thereafter. In other words,
particular attention needs to be paid to the changes in the
behavior for the reacceleration, since it is highly likely to
execute the reacceleration control after the deceleration in the
travel scene. In that sense, the travel control device and the
travel control method of the present embodiment is effectively
applied to the travel scene in which the subject vehicle V1
decelerates in response to the oncoming vehicle V2.
[0066] According to the travel control device and the travel
control method of the present embodiment, the deceleration start
position P4 is determined at which the deceleration of the subject
vehicle V1 starts so that the subject vehicle V1 does not come into
contact with the oncoming vehicle V2 entering into the travel lane
L1. Then, whether the subject vehicle V1 arrives at the
deceleration start position P4 is detected. When the subject
vehicle V1 arrives at the deceleration start position P4, the
deceleration travel control of the subject vehicle V1 is executed.
In particular, whether the subject vehicle V1 arrives at the
deceleration start position P4 may be detected, and the
deceleration travel control may be executed once the subject
vehicle V1 arrives at the deceleration start position P4, with the
initial deceleration larger than the initial deceleration in the
case that the subject vehicle V1 does not arrive at the
deceleration start position P4.
[0067] Alternatively, the stop position P2 for stopping the subject
vehicle V1 so that the subject vehicle V1 does not come into
contact with the oncoming vehicle V2 entering into the travel lane
L1 in which the subject vehicle V1 travels is set on the basis of
the situation ahead of the subject vehicle V1. Further, the
deceleration start position P4 for starting the deceleration of the
subject vehicle V1 is determined on the basis of the set stop
position P2, the current position P1 of the subject vehicle V1, the
current vehicle speed of the subject vehicle V1, the predetermined
reference deceleration, and the initial deceleration. Then, whether
the subject vehicle V1 arrives at the deceleration start position
P4 is detected, and once the subject vehicle V1 arrives at the
deceleration start position P4, the deceleration travel control of
the subject vehicle V1 is executed. At this time, the target
vehicle speed profile for decelerating the subject vehicle V1 with
the predetermined reference deceleration from the current position
P1 may be set, the passing position P3 at which the subject vehicle
V1 and the oncoming vehicle V2 pass each other may be determined on
the basis of the target vehicle speed profile and vehicle speed of
the oncoming vehicle V2, and the initial deceleration upon
executing the deceleration travel control of the subject vehicle V1
may be set on the basis of the relative positional relation between
the stop position P2 and the passing position P3.
[0068] Further, according to the travel control device and the
travel control method of the present embodiment, when the passing
position P3 at which the subject vehicle V1 and the oncoming
vehicle V2 pass each other is on the subject vehicle side (the near
side) relative to the stop position P2, the initial deceleration
.alpha.1 in the case of the distance between the stop position P2
and the passing position P3 being relatively large is set smaller
than the predetermined reference deceleration .alpha. and smaller
than the initial deceleration in the case of the distance between
the stop position P2 and the passing position P3 being relatively
small. As a result, the larger the distance between the stop
position P2 and the passing position P3 is, the longer the grace
time for making the determination on the travel control of the
subject vehicle V1 can be secured. In other words, the travel
control of the subject vehicle V1 can be executed in response to
the behavior of the oncoming vehicle V2 in the grace time.
Therefore, it is possible to further suppress the unnecessary stop
or the unnecessary acceleration. As a result, the discomfort of the
occupant can be further suppressed.
[0069] Further, according to the travel control device and the
travel control method of the present embodiment, on the basis of
the set stop position P2, the current position P1 of the subject
vehicle V1, the current vehicle speed of the subject vehicle V1,
and the predetermined reference deceleration .alpha., the
deceleration start position P4 ahead of the subject vehicle V1 is
determined. Then, whether the subject vehicle V1 arrives at the
deceleration start position P4 is detected. When the subject
vehicle V1 arrives at the deceleration start position P4, the
deceleration travel control of the subject vehicle V1 is executed.
As a result, the long grace time for making the determination on
the travel control of the subject vehicle V1 can be secured. At the
same time, the subject vehicle V1 can be stopped at the stop
position P1 at the optimum time.
[0070] Further, according to the travel control device and the
travel control method of the present embodiment, when the
deceleration travel control of the subject vehicle V1 is executed
with the set initial deceleration .alpha.1, the set initial
deceleration .alpha.1 is switched to the predetermined final
deceleration .alpha.2 at the timing at which the subject vehicle V1
can be stopped at the stop position P2 when the set initial
deceleration .alpha.1 is switched to the predetermined final
deceleration .alpha.2. The final deceleration .alpha.2 is used to
the deceleration travel control of the subject vehicle V1. As a
result, the long grace time for making the determination on the
travel control of the subject vehicle V1 can be secured. At the
same time, the subject vehicle V1 can be surely stopped at the stop
position P2.
[0071] Further, according to the travel control device and the
travel control method of the present embodiment, when it is
determined that the subject vehicle V1 cannot be stopped at the
stop position P2 during the period to switch the initial
deceleration .alpha.1 to the predetermined final deceleration
.alpha.2, the final deceleration is switched to the deceleration
larger than the predetermined final deceleration .alpha.2. Then,
the deceleration travel control of the subject vehicle V1 is
executed. As a result, the long grace time for making the
determination on the travel control of the subject vehicle V1 can
be secured. At the same time, the subject vehicle V1 can be surely
stopped at the stop position P2 even when the travel situation
changes.
[0072] Further, according to the travel control device and the
travel control method of the present embodiment, the initial
deceleration .alpha.1 is the predetermined value. This enables to
set the deceleration that does not discomfort the occupant.
[0073] Further, according to the travel control device and the
travel control method of the present embodiment, the initial
deceleration .alpha.1 includes the plurality of initial
deceleration values. As a result, the long grace time for making
the determination on the travel control of the subject vehicle V1
can be secured. At the same time, the vehicle speed before and
after passing by can be set so that the jerk becomes small.
[0074] Further, according to the travel control device and the
travel control method of the present embodiment, the initial
deceleration .alpha.1 includes the plurality of initial
deceleration values. Further, the initial deceleration that is set
finally in terms of time (i.e., the initial deceleration just
before switching to the final deceleration .alpha.2) is set to the
smallest initial deceleration of the plurality of initial
deceleration values. As a result, the long grace time for making
the determination on the travel control of the subject vehicle V1
can be secured. At the same time, the jerk at the time of the
reacceleration after passing by is decreased.
[0075] Further, according to the travel control device and the
travel control method of the present embodiment, when the passing
position P3 is on the oncoming vehicle side (the far side) relative
to the stop position P2, instead of setting the initial
deceleration .alpha.1, the predetermined reference deceleration
.alpha. is set to the final deceleration. Further, whether the
subject vehicle V1 can be stopped at the stop position P2 is
determined on the basis of the set final deceleration .alpha., the
current position P1 of the subject vehicle V1, the current vehicle
speed of the subject vehicle V1, and the stop position P2. As a
result, when it is determined that the subject vehicle V1 cannot be
stopped at the stop position P2, the final deceleration is switched
to the deceleration larger than the set final deceleration .alpha..
As a result, the long grace time for making the determination on
the travel control of the subject vehicle V1 can be secured. At the
same time, the subject vehicle V1 can be surely stopped at the stop
position P2 even when the travel situation changes.
[0076] Further, according to the travel control device and the
travel control method of the present embodiment, the behavior of
the oncoming vehicle V2 is detected while executing the
deceleration travel control of the subject vehicle V1 with the
deceleration in accordance with the deceleration profile. Then, it
is predicted whether the subject vehicle V1 can travel in the
travel lane L1 without coming into contact with the oncoming
vehicle V2. When it is predicted that the subject vehicle V1 can
travel in the travel lane L1 without coming into contact with the
oncoming vehicle V2, the deceleration travel control is stopped,
and the target speed is generated in which the deceleration is not
performed. As a result, the long grace time for making the
determination on the travel control of the subject vehicle V1 can
be secured. At the same time, it is possible to smoothly transit to
the subsequent travel control, such as executing the reacceleration
control.
[0077] In the travel control device and the travel control method
of the present embodiment as mentioned above, the values of the
deceleration .alpha., .alpha.1, and .alpha.2 are set to the
appropriate values as control factors. However, the vehicle speed
corresponding to the deceleration .alpha., .alpha.1, and .alpha.2
may be used as the control factors.
DESCRIPTION OF REFERENCE NUMERALS
[0078] VTC . . . Vehicle travel controller (travel control device
for a vehicle) [0079] 11 . . . Radar device [0080] 12 . . . Camera
[0081] 13 . . . Map database [0082] 14 . . . Position detecting
device [0083] 15 . . . Vehicle speed sensor [0084] 21 . . .
Oncoming vehicle route predicting unit [0085] 22 . . . Subject
vehicle route predicting unit [0086] 23 . . . Travelability
determination unit [0087] 24 . . . Target vehicle speed generating
unit [0088] 25 . . . Vehicle speed track control unit [0089] 51 . .
. Drive control device [0090] 52 . . . Engine [0091] 53 . . . Brake
control device [0092] 54 . . . Brake [0093] V1 . . . Subject
vehicle [0094] V2 . . . Oncoming vehicle [0095] V3 . . . Parked
vehicle [0096] L1 . . . Travel lane [0097] L2 . . . Opposite lane
[0098] P1 . . . Current position of subject vehicle [0099] P2 . . .
Stop position [0100] P3 . . . Passing position [0101] P4 . . .
Deceleration start position [0102] R . . . Approach route [0103]
.alpha. . . . Reference deceleration [0104] .alpha.1 . . . Initial
deceleration [0105] .alpha.2 . . . Final deceleration
* * * * *