U.S. patent application number 12/757905 was filed with the patent office on 2010-10-07 for vehicle surroundings monitoring apparatus and traveling control system incorporating the apparatus.
This patent application is currently assigned to Fuji Jukogyo Kabushiki Kaisha. Invention is credited to Hiroyuki SEKIGUCHI.
Application Number | 20100256910 12/757905 |
Document ID | / |
Family ID | 32024884 |
Filed Date | 2010-10-07 |
United States Patent
Application |
20100256910 |
Kind Code |
A1 |
SEKIGUCHI; Hiroyuki |
October 7, 2010 |
VEHICLE SURROUNDINGS MONITORING APPARATUS AND TRAVELING CONTROL
SYSTEM INCORPORATING THE APPARATUS
Abstract
A vehicle surroundings monitoring apparatus, comprises frontal
information detecting means for detecting solid object information
in front of an own vehicle, preceding vehicle recognizing means for
recognizing a preceding vehicle based on the solid object
information, traveling path estimating means for estimating a
traveling path of the own vehicle, first evacuation possibility
judging means for judging a first possibility of relative
evacuation between the preceding vehicle and the own vehicle
according to positions of the preceding vehicle and the own
vehicle, second evacuation possibility judging means for judging a
second possibility of relative evacuation between the preceding
vehicle and the own vehicle according to information of solid
objects other than the preceding vehicle, and preceding vehicle
evacuation possibility judging means for judging a final
possibility of relative evacuation between the preceding vehicle
and the own vehicle based on the first possibility and the second
possibility.
Inventors: |
SEKIGUCHI; Hiroyuki; (Tokyo,
JP) |
Correspondence
Address: |
MCDERMOTT WILL & EMERY LLP
600 13TH STREET, N.W.
WASHINGTON
DC
20005-3096
US
|
Assignee: |
Fuji Jukogyo Kabushiki
Kaisha
Tokyo
JP
|
Family ID: |
32024884 |
Appl. No.: |
12/757905 |
Filed: |
April 9, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10664089 |
Sep 17, 2003 |
7725261 |
|
|
12757905 |
|
|
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Current U.S.
Class: |
701/301 |
Current CPC
Class: |
B60K 31/00 20130101 |
Class at
Publication: |
701/301 |
International
Class: |
G08G 1/16 20060101
G08G001/16 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 18, 2002 |
JP |
2002-271906 |
Claims
1-10. (canceled)
11. A vehicle surroundings monitoring apparatus having a vehicle
surroundings monitoring program configured to: detect solid object
information ahead of an own vehicle based on signals from a camera
of the own vehicle; estimate a travel path of the own vehicle based
on signals from at least one of the camera, a yaw rate sensor, a
vehicle speed sensor and a steering angle sensor of the own
vehicle; recognize a preceding vehicle traveling in front of the
travel path of the own vehicle based on the solid object
information; establish a plurality of regions around the own travel
path in response to both lengthwise and a widthwise distance from
the own vehicle; provide parameters corresponding to the respective
regions; accumulate said parameters provided to the regions where
the preceding vehicle exists in a case where the preceding vehicle
exists in one of the regions; judge whether the number of
accumulated parameters is larger than a threshold value; and output
a signal indicating that the preceding vehicle is not traveling in
front of the travel path of the own vehicle in a case where the
number of accumulated parameters is larger than the threshold
value.
12. The vehicle surroundings monitoring apparatus according to.
claim 11, wherein the number of accumulated parameters is cleared
when the lengthwise distance of the preceding vehicle is farther
than a preestablished distance.
13. The vehicle surroundings monitoring apparatus according to
claim 11, wherein the parameter is set to increase when the region
is in farther than an area of a predetermined width and length
around the travel path of the own vehicle.
14. The vehicle surroundings monitoring apparatus according to
claim 13, wherein the parameter is set to increase as the region is
near the own vehicle region.
15. A travel control system for controlling the travel of an own
vehicle at least based on the output signal from the vehicle
surroundings monitoring apparatus described in claim 11.
16. The vehicle surroundings monitoring apparatus according to
claim 11, wherein the number of accumulated parameters is adjusted
to increase when any forward traveling object other than the
preceding vehicle has been judged based on the solid object
information.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the invention
[0002] The present invention relates to a vehicle surroundings
monitoring apparatus for recognizing traveling circumstances in
front of an own vehicle by stereoscopic cameras, monocular cameras,
millimeter wave radars, and the like and for making an accurate
judgment of evacuation of a preceding vehicle from the lane and,
more particularly to a traveling control system incorporating such
a vehicle surroundings monitoring apparatus.
[0003] 2. Discussion of related arts
[0004] In recent years, such a traveling control system as
detecting traveling circumstances in front of an own vehicle by a
camera and the like mounted on a vehicle, estimating traveling
paths of the own vehicle from the traveling circumstances data,
detecting a preceding vehicle traveling ahead of the own vehicle
and making a follow-up control of the preceding vehicle or an
intervehicle distance control between the own vehicle and the
preceding vehicle, has been put into practical use.
[0005] For example, Japanese Patent Application Laid-open No.
Toku-Kai-Hei 9-91598 discloses a traveling control system in which
a traveling path of an own vehicle is estimated from traveling
conditions such as yaw rate and other data and a nearest obstacle
on the traveling path is detected as a preceding vehicle to be
monitored. Further, in the traveling control system, when the
preceding vehicle goes out of the traveling path of the own
vehicle, the monitoring of the preceding vehicle is released.
[0006] In the traveling control system, the technology of
recognizing a preceding vehicle is very important. The preceding
vehicle sometimes travels in such a manner as trying to avoid an
obstacle, sometimes changes the lane, and sometimes goes out of the
lane and other vehicle enters the lane in place of the preceding
vehicle. If the traveling control system fails to correctly catch
the behavior of the preceding vehicle, the traveling control
becomes awkward and rather inconvenient for a vehicle driver.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide a
vehicle surroundings monitoring apparatus capable of accurately
continuing to monitor a preceding vehicle and catching behaviors of
the preceding vehicle such as evacuation of a preceding vehicle
from a traveling path of an own vehicle, intrusion of a different
vehicle in place of the preceding vehicle and the like with quick
response and to provide a traveling control system incorporating
such a vehicle surroundings monitoring apparatus.
[0008] In order to attain the object , a vehicle surroundings
monitoring apparatus, comprises frontal information detecting means
for detecting solid object information in front of an own vehicle,
preceding vehicle recognizing means for recognizing a preceding
vehicle based on the solid object information, traveling path
estimating means for estimating a traveling path of the own
vehicle, first evacuation possibility judging means for judging a
first possibility of relative evacuation between the preceding
vehicle and the own vehicle according to positions of the preceding
vehicle and the own vehicle, second evacuation possibility judging
means for judging a second possibility of relative evacuation
between the preceding vehicle and the own vehicle according to
information of solid objects other than the preceding vehicle, and
preceding vehicle evacuation possibility judging means for judging
a final possibility of relative evacuation between the preceding
vehicle and the own vehicle based on the first possibility and the
second possibility.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic diagram showing a traveling control
system incorporating a vehicle surroundings monitoring apparatus
according to the present invention;
[0010] FIG. 2 is a flowchart showing a routine for monitoring
surroundings of a vehicle;
[0011] FIG. 3 is a flowchart showing a routine for estimating a
traveling path of an own vehicle;
[0012] FIG. 4 is a flowchart showing a routine for judging the
possibility of evacuation of a preceding vehicle using a traveling
path C of an own vehicle;
[0013] FIG. 5a is an explanatory diagram showing a process of
producing a new traveling path C of an own vehicle from the
traveling path A and the traveling path B;
[0014] FIG. 5b is an explanatory diagram showing a process of
producing the new traveling path C when the traveling path A is
erroneously recognized;
[0015] FIG. 5c is an explanatory diagram showing a process of
calculating a new traveling path E from the traveling path C and
the traveling path D (traveling path of a preceding vehicle) ;
and
[0016] FIG. 6 is an explanatory diagram showing a process for
establishing a judging counter.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] Referring now to FIG. 1, reference numeral 1 denotes a
vehicle (own vehicle) on which an intervehicle distance
automatically adjusting system (Adaptive Cruise Control: ACC) 2 is
mounted. The ACC system 2 is constituted by a traveling control
unit 3, a stereoscopic camera 4 and a vehicle surroundings
monitoring apparatus 5. When the ACC system is set to a constant
speed control mode, the vehicle travels at a speed established by a
vehicle driver and when the system is set to a follow-up traveling
control mode, the vehicle travels at a speed targeted to the speed
of a preceding vehicle with a constant intervehicle distance to the
preceding vehicle maintained.
[0018] The stereoscopic camera 4 constituting vehicle forward
information detecting means is composed of a pair (left and right)
of CCD cameras using a solid-state image component such as Charge
Coupled Device and the left and right cameras are transversely
mounted on a front ceiling of a passenger compartment at a
specified interval of distance, respectively. The respective
cameras take picture images of an outside object from different
view points and input the picture images to the vehicle
surroundings monitoring apparatus 5.
[0019] Further, the vehicle 1 has a vehicle speed sensor 6 for
detecting a vehicle speed and the detected vehicle speed is
inputted to the traveling control unit 3 and the vehicle
surroundings monitoring apparatus 5, respectively. Further, the
vehicle 1 has a steering angle sensor 7 for detecting a steering
angle and a yaw rate sensor 8 for detecting a yaw rate and the
detected steering angle and yaw rate signals are inputted to the
vehicle surroundings monitoring apparatus 5. Further, a signal from
a turn signal switch 9 is inputted to the vehicle surroundings
monitoring apparatus 5. These sensors 6, 7, 8 and the switch 9 act
as own vehicle traveling conditions detecting means.
[0020] The vehicle surroundings monitoring apparatus 5 inputs
respective signals indicative of picture images from the
stereoscopic camera 4, vehicle speeds, steering angle, yaw rate and
turn signal and detects frontal information about solid objects ,
side walls and lane markers in front of the vehicle 1 based on the
picture images inputted from the stereoscopic camera 4. Then, the
apparatus estimates several traveling paths of the own vehicle 1
from the frontal information and traveling conditions of the own
vehicle 1 according to the flowchart which will be described
hereinafter and estimates a final traveling path of the own vehicle
1 from those traveling paths. Further, the apparatus establishes a
traveling region A corresponding to a detected solid object based
on the final traveling path. Further, the apparatus establishes a
traveling region B corresponding to the solid object based on at
least either of the traveling region A and the traveling road
information and judges whether the solid object is a preceding
vehicle, a tentative preceding vehicle or others according to the
state of existence of the solid object in the traveling regions A
and B. As a result of the judgment, a preceding vehicle in front of
the own vehicle 1 is extracted and the result is outputted to the
traveling control unit 3.
[0021] Describing the process of estimating the traveling path of
the own vehicle (hereinafter referred to as "own traveling path")
in brief, a new own traveling path C is calculated from the own
traveling path A (first own traveling path) obtained based on lane
markers and side walls and the own traveling path B (second own
traveling path) obtained based on yaw rates of the own vehicle.
Then, the possibility of evacuation of the preceding vehicle is
judged from the relationship between the own traveling path C, the
preceding vehicle and the solid object in the vicinity of the
preceding vehicle. In case where there is no possibility of
evacuation of the preceding vehicle, the turn signal switch is
turned off, and the absolute value of the steering wheel rotation
angle is smaller than a specified value, a new own traveling path E
is calculated from the own traveling path C and the locus of the
preceding vehicle and a present own traveling path is calculated
from the own traveling path E and the previous own traveling path.
On the other hand, in case where the conditions described above are
not satisfied, a present own traveling path is calculated from the
own traveling path C and the previous own traveling path. The
vehicle surroundings monitoring apparatus 5 comprises forward
information detecting means, preceding vehicle recognizing means,
own traveling path estimating means, first evacuation possibility
judging means and second evacuation possibility judging means.
[0022] Describing the processing of images from the stereoscopic
camera 4 in the vehicle surroundings monitoring apparatus 5, with
respect to a pair of stereoscopic images taken by the stereoscopic
CCD camera 4, distance information over the entire image is
obtained from the deviation amount between corresponding positions
according to the principle of trianguration and a distance image
representing three-dimensional distance distribution is formed
based on the distance information. Then, lane marker data, side
wall data such as guardrails, curbs and side walls arranged along
the road and solid object data such as vehicles and the like, are
extracted by means of the known grouping process and the like by
comparing the distance image with the three-dimensional road
profile data, side wall data, solid object data and the like stored
beforehand. Thus extracted lane marker data, side wall data and
solid object data are denoted by different numbers respectively.
Further, the solid object data are classified into three kinds of
objects, a backward moving object moving toward the own vehicle 1 a
still object in standstill and a forward moving object moving in
the same direction as the own vehicle 1 based on the relationship
between the relative variation of the distance from the own vehicle
and the vehicle speed of the own vehicle 1 and the respective solid
object data are outputted.
[0023] The traveling control unit 3 is equipped with a function of
a constant speed traveling control for maintaining the vehicle
speed at a value inputted by the vehicle driver and a function of a
follow-up traveling control for following up the preceding vehicle
in a condition to keep the intervehicle distance between the own
vehicle 1 and the preceding vehicle constant . The traveling
control unit 3 is connected with a constant speed traveling switch
10 constituted by a plurality of switches operated by a constant
speed traveling selector lever provided on the side surface of a
steering column, the vehicle surroundings monitoring apparatus 5,
the vehicle speed sensor 6 and the like.
[0024] The constant speed traveling switch 10 is constituted by a
speed setting switch for setting a target vehicle speed at the
constant speed traveling mode, a coast switch for changing the
target vehicle speed in a descending direction and a resume switch
for changing the target vehicle speed in an ascending direction.
Further, a main switch (not shown) for turning the traveling
control on or off is disposed in the vicinity of the constant speed
traveling selector lever.
[0025] When the driver turns a main switch (not shown) on and sets
a desired vehicle speed by operating the constant speed traveling
selector lever, a signal indicative of the desired vehicle speed
inputs from the constant speed traveling switch 10 to the traveling
control unit 3 and a throttle valve 12 driven by a throttle
actuator 11 makes a feed-back control so as to converge the vehicle
speed detected by the vehicle speed sensor 6 to the established
vehicle speed. As a result, the own vehicle 1 can travel at a
constant speed automatically.
[0026] Further, when the traveling control unit 3 makes a constant
traveling control, supposing a case where the vehicle surroundings
monitoring apparatus 5 recognizes a preceding vehicle, which is
traveling at a lower speed than the established vehicle speed, the
traveling control unit 3 automatically changes over to a follow-up
traveling control mode in which the own vehicle travels in a
condition retaining at a constant intervehicle distance.
[0027] When the constant speed traveling control mode is
transferred to the follow-up traveling control mode, a target value
of an appropriate intervehicle distance between the own vehicle 1
and the preceding vehicle is established based on the intervehicle
distance obtained from the vehicle surroundings monitoring
apparatus 5, the vehicle speed of the own vehicle 1 detected by the
vehicle speed sensor 6 and the vehicle speed of the preceding
vehicle obtained from the intervehicle distance and the vehicle
speed of the own vehicle 1 . Further, the traveling control unit 3
outputs a drive signal to the throttle actuator 11 and makes a
feed-back control of the opening angle of the throttle valve 12 so
that the intervehicle distance agrees with the target value and
controls the own vehicle 1 in a condition following up the
preceding vehicle with the intervehicle distance retained.
[0028] Next, a vehicle surroundings monitoring program of the
vehicle surroundings monitoring apparatus 5 will be described by
referring to a flowchart shown in FIG. 2.
[0029] In this embodiment, the coordinate system of the
three-dimensional real space is transferred to a coordinate system
fixed to the own vehicle. That is , the coordinate system is
composed of X coordinate extending in a widthwise direction of the
own vehicle, Y coordinate extending in a vertical direction of the
own vehicle, Z coordinate extending in a lengthwise direction of
the own vehicle and an origin of the coordinate placed on the road
surface directly underneath the central point of two CCD cameras.
The positive sides of X, Y and Z coordinates are established in a
right direction, in an upward direction and in a forward direction,
respectively.
[0030] The routine shown in FIG. 2 is energized every 50
milliseconds. First at a step (hereinafter abbreviated as S) 101,
solid object data, side wall data including guardrails, curbs
provided along the road and lane marker data are recognized based
on images taken by the stereoscopic camera 4. Further, with respect
to the solid object data, they are classified into three kinds of
objects, backward moving objects, still objects and forward moving
objects as described above.
[0031] Next, the program goes to S102 where the traveling path of
the own vehicle is estimated according to a flowchart which will be
described hereinafter shown in FIG. 3. First, at S201, the
presently obtained own traveling path Xpr(n)[i] is stored as a
previous own traveling path Xpr(n-1)[1]. [I] denotes node numbers
(segment numbers) attached to the own traveling path extending
forward from the own vehicle 1. In this embodiment, the own
traveling path has 24 segments in a forward direction and is
composed of a plurality of straight lines connected with each
other. Accordingly, Z coordinate at the segment i is established as
follows. Z coordinate at segment i=10. 24 meters [0032] +i4.096
meters (I=0 to 23)
[0033] Then, the program goes to S202 where an own traveling A
(Xpra[i], i=0 to 23) is calculated according to the following
method A or B.
Method A: Estimation of Traveling Path Based on Lane Markers
[0034] In case where both or either of left and right lane markers
data are obtained and the profile of the lane on which the own
vehicle 1 travels can be estimated from these lane markers data,
the traveling path of the own vehicle is formed in parallel with
the lane markers in consideration of the width of the own vehicle 1
and the position of the own vehicle 1 in the present lane.
Method B: Estimation of Traveling Path Based on Side Wall Data
[0035] In case where both or either of left and right side walls
data are obtained and the profile of the lane on which the own
vehicle 1 travels can be estimated from these side walls data, the
traveling path of the own vehicle is formed in parallel with the
side walls in consideration of the width of the own vehicle 1 and
the position of the own vehicle 1 in the present lane.
[0036] In case where the own traveling path A can not be
established according to any of the methods A, B, it is calculated
according to the following methods C or D.
Method C: Estimation Of Traveling Path Based on a Trace of the
Preceding Vehicle
[0037] The own traveling path is estimated based on the past
traveling trace extracted from the solid object data of the
preceding vehicle.
Method D: Estimation of Path Based on Trace of the Own Vehicle
[0038] The own traveling path is estimated based on the traveling
conditions such as yaw rate .gamma., vehicle speed V and steering
wheel rotation angle .theta. H of the own vehicle 1.
[0039] After that, the program goes to S203 in which an own
traveling path B (Xprb[I], I=0 to 23) is calculated based on the
yaw rate .gamma. according to the following processes.
[0040] Xprb[i]=.gamma.Z.sup.2+10240 (millimeters)
[0041] Z=4096i+10240 (millimeters)
[0042] Thus obtained own traveling path B (Xprb[i]) is corrected as
follows by the state of the steering wheel rotation angle .theta.
H, that is, by respective states, during traveling
straightforwardly, during turning a curve and during returning the
steering wheel to straight.
[0043] Xprb[i]=Xprb[i].alpha.
where .alpha. is a correction coefficient.
[0044] The correction coefficient .alpha. is established to a value
(.noteq.0) from 0 to 1.0. When the vehicle travels straight or when
the vehicle transfers from curve to straight, the correction
coefficient .alpha. is established to a small value so as to reduce
the curvature of the traveling path. When the vehicle turns a
curve, the correction coefficient .alpha. is established to 1.0 so
as to employ the curvature derived from the yaw rate y as it
is.
[0045] Then, the program goes to S204 where an own traveling path C
(Xprc[i], i=0 to 23) is calculated based on the own traveling path
A (Xpra[i], i=0 to 23) and the own traveling path B (Xprb[i], i=0
to 23) as shown in FIG. 5a.
[0046] Xprc[i]=(Xpra[i].lamda.+Xprb[i].mu./(.lamda.+.mu.)
where .lamda. and .mu. are values varying according to the result
of recognition of circumstances such as road widths.
[0047] Thus, in case where the accuracy of the own traveling path A
(Xpra , i=0 to 23) is exacerbated by erroneous recognition of lane
markers or side walls as shown in FIG. 5b, for example, the
recognition accuracy of the own traveling path can be prevented
from going down by primarily using the own traveling path B
(Xprb[i]i=0 to 23) by means of establishing .mu. to a larger value
than .lamda..
[0048] Then, the program goes to S205 in which it is judged whether
or not a preceding vehicle is detected and if detected, the program
goes to S206 where the segment kpo on Z coordinate of the preceding
vehicle is established as follows:
[0049] Kpo=(Z coordinate of preceding vehicle -10.24)/4.096
[0050] Then, the program goes to S207 in which the possibility of
evacuation of the preceding vehicle is judged using the own
traveling path C (Xprc[i], i=0 to 23) calculated at S204, according
to a flowchart shown in FIG. 4.
[0051] In this routine, first, at S301, it is judged whether or not
a preceding vehicle exists. If there is no preceding, the program
goes to S302 wherein a judging counter TIME is cleared (TIME=0) and
then goes to S303 wherein it is judged that there is no preceding
vehicle and such a signal is outputted, leaving the routine. In
this embodiment, the signal is the same as a signal indicating that
there is a possibility of evacuation of the preceding vehicle.
Further, the aforesaid judging counter TIME is for expressing the
possibility of evacuation of the preceding vehicle numerically.
[0052] On the other hand, in case where it is judged at S301 that
there is a preceding vehicle, the program goes to S304 where the
absolute value CAL of the difference between X coordinate kpx of
the preceding vehicle and X coordinate of the own traveling path C
(Xprc[i], i=0 to 23) on Z coordinate of the preceding vehicle, is
calculated (CAL=|kpx-xpx|).
[0053] The processes from S305 to S311 will be described by
reference to FIG. 6.
[0054] First, at S305, it is judged whether or not the segment kpo
of Z coordinate of the preceding vehicle is larger than 17.that is,
the division is more than 80 meters ahead. If kpo is larger than
17, the program goes to S306 in which the judging counter TIME is
cleared (TIME=0) and then goes to S307 a signal indicative of no
possibility of evacuation of the preceding vehicle is outputted,
leaving the routine.
[0055] Further, in case where it is judged at S305 that the segment
kpo of Z coordinate of the preceding vehicle is smaller than 80
meters, the program goes to S308 in which the judgment counter TIME
is initialized according to the position of the preceding vehicle
as follows (first evacuation possibility judging means):
A. In case where CAL is smaller than 500 millimeters, that is, the
preceding vehicle is in the vicinity of the traveling path of the
own vehicle (region 1 of FIG. 6),
[0056] TIME=0
B. In case where CAL is larger than 500 millimeters, that is, the
preceding vehicle is regarded as traveling apart from the traveling
path of the own vehicle
[0057] (1) In case where the segment kpo of Z coordinate of the
preceding vehicle is smaller than 80 meters and larger than 50
meters:
[0058] In case of 2000.ltoreq.CAL.ltoreq.3000 millimeters (region
II of FIG. 6)
[0059] TIME=TIME+5
[0060] In case of other than above (particularly, outside of the
region II, note that the preceding vehicle travels around
curves)
[0061] TIME=TIME-5
[0062] (2) In case where the segment kpo of Z coordinate of the
preceding vehicle is smaller than 50 meters and larger than 30
meters:
[0063] In case of 1500.ltoreq.CAL.ltoreq.2500 millimeters (region
III of FIG. 6)
[0064] TIME=TIME+10
[0065] In case of other than above (particularly, outside of the
region III, note that the preceding vehicle travels around
curves)
[0066] TIME=TIME-10
[0067] (3) In case where the segment of kpo of Z coordinate of the
preceding vehicle is smaller than 30 meters:
[0068] In case of CAL.gtoreq.1000 millimeters (region IV of FIG.
6)
[0069] TIME=TIME+30
[0070] In case other than above
[0071] TIME=TIME-10
[0072] Then, the program goes to S309 wherein the judging counter
TIME is established by the solid object other than the preceding
vehicle (second evacuation possibility judging means). For example,
in case where a forward traveling solid object enters a traveling
region kpo the judging counter TIME initialized by S308 is
additionally initialized as follows:
[0073] TIME=TIME+10
[0074] Then, the program goes to S310 in which it is judged whether
or not TIME is larger than a threshold value (for example 100) . If
TIME is smaller than 100, the program goes to S307 where after a
signal indicative of no possibility of evacuation of the preceding
vehicle is outputted, the program leaves the routine. If TIME is
larger than 100, the program goes to S311 where a signal indicative
of the possibility of evacuation of the preceding vehicle is
outputted and leaves the routine. Thus, since the judgment of
evacuation of the preceding vehicle is made by the own traveling
path C (Xprc[i], i=0 to 23) and the position where the preceding
vehicle exists, even when no lane markers are seen, an accurate
judgment of evacuation of the preceding vehicle is available.
Further, the accurate judgment of evacuation of the preceding
vehicle can prevent the ACC system from following up the preceding
vehicle hazardously.
[0075] Since the introduction of this evacuation judgment process
enables an accurate judgment of the possibility of evacuation of
the preceding vehicle as a monitoring object based on information
of the position of the preceding vehicle, the traveling path of the
own vehicle and the objects in the neighborhood of the preceding
vehicle, not only the preceding vehicle can be continued to be
caught as a monitoring object, but also every behavior of the
preceding vehicle including the change of the preceding vehicle
from one to another can be detected with quick responsibility and
accuracy. As a result, the traveling control can be executed stably
in a manner similar to driver's driving senses.
[0076] Thus, after the judging processes of the possibility of
evacuation of the preceding vehicle are executed using the own
traveling path C (Xprc[i], i=0 to 23) at S207, the program goes to
S208 where it is judged from the result of the judgment at S207
whether or not there is a possibility of evacuation of the
preceding vehicle.
[0077] If it is judged that there is no possibility of evacuation
of the preceding vehicle, the program goes to S209 wherein it is
judged whether or not the turn signal switch 9 of the own vehicle
is turned on. If the turn signal switch 9 is turned off, the
program goes to S210 in which it is judged whether or not the
absolute value of the steering wheel rotation angle is larger than
a specified value, for example 90 degrees. If it is smaller than
the specified value, the program goes to S211 where a new own
traveling path E (Xpre[i], i=0 to 23) is based on the own traveling
path C (Xprc[i], i=0 to 23) and the own traveling path D (Xpre[i],
i=0 to 23) according to the following formula:
[0078] Xpre[i]=Xprc[i]
where i=0 to (kpo-2), (kpo+1) to 23
[0079] Xpre[i]=(Xprc[I]+xpo.kappa.)/ (1.0+.kappa.)
where i=kpo-1, kpo In this embodiment, the own traveling path D is
expressed only by X coordinate xpo at the segment kpo of Z
coordinate of the preceding vehicle. Further, .kappa. is a variable
varying according to the recognition of circumstances. When the
recognition of circumstances is inferior, .kappa. is established to
a large value. That is, in the process of S211, as shown in FIG.
5c, taking the case where the preceding vehicle changes the lane
into consideration, only the neighborhood of the preceding vehicle
is corrected with respect to the preceding vehicle so that the ACC
system 2 operates with accuracy.
[0080] Then, the program goes to S212 wherein the present own path
(Xprc[i], i=0 to 23) is calculated from the own traveling path E
(Xpre[i], i=0 to 23) newly calculated presently and the own
traveling path (Xpr(n-1)[i], i=0 to 23) calculated in the previous
cycle and stored at S201 as follows:
[0081] Xpr(n)[1]=Xpr(n-1)[i].phi.-Xpre[i]-(1.0-.phi.
where .phi. is a value established according to traveling
conditions of the own vehicle. For example, when the vehicle
transfers from curved road to straight road, .phi. is established
to a small value so as to impose more weight on the own traveling
path E (Xpre[i], i=0 to 23) calculated newly, presently and
otherwise .phi. is established to a large value so as to impose
more weight on the own traveling path (Xpr(n-1)[i], i=0 to 23)
calculated in the previous cycle. As a result, the response in
accordance with the traveling conditions can be obtained.
[0082] On the other hand, in case where it is judged at S205 that
there is no preceding vehicle, or in case where it is judged at
S208 that there is a possibility of evacuation, the program goes to
S213. Similarly, in case where it is judged at S209 that the turn
signal switch 9 is turned on, or in case where it is judged at S210
that the absolute value of the steering wheel rotation angle is
larger than a specified value, the program goes to S213.
[0083] At S213, the present own traveling path (Xpr(n)[i], i=0 to
23) is calculated from the own traveling path C (Xprc[i], i=0 to
23) calculated at S204 and the previous own traveling path
(Xpr(n-1)[1], i=0 to 23) stored at S201 in the following
manner:
[0084] Xpr(n)[i]=Xpr(n-1)[i].phi.-Xprc[i](1.0-.phi.)
[0085] After the own traveling path is estimated, the program goes
to S103 where the preceding vehicle is extracted, leaving the
routine. The extraction of the preceding vehicle is performed as
follows:
[0086] First, the traveling region A is established based on the
traveling path of the own vehicle according to the solid object .
Further, the traveling region B is established based on at least
either of the traveling region A and road information (road profile
estimated from lane markers and side walls). Then, if the detected
solid object exists in the traveling region A and if the duration
for which the solid object stays in either of the traveling regions
A and B, is larger than a specified time and if the solid object is
a forward moving object and if the object is nearest one to the own
traveling vehicle 1, the solid object is regarded and extracted as
a preceding vehicle.
[0087] According to the embodiment of the present invention, since
the final own traveling path is calculated based upon the own
traveling path A (Xpra[i], i=0 to 23) obtained from lane marker and
side wall data and the own traveling path B (Xprb[i], i=0 to 23)
derived from the yaw rate of the own vehicle 1 and the own
traveling path D (Xprd[i], i=0 to 23) calculated based on the trace
of the preceding vehicle, the own traveling path can be estimated
accurately, stably and securely.
[0088] Further, when the own traveling path C (Xprc[i], i=0 to 23)
is calculated from the own traveling path A (Xpra[i], i=0 to 23)
and the own traveling path B (Xprb[i], i=0 to 23) and the own
traveling path E (Xpre[i], i=0 to 23) is newly calculated using the
own traveling path C (Xprc[i], i=0 to 23) and the own traveling
path D (Xprd[i], i=0 to 23) produced based on the traveling trace
of the preceding vehicle, since an accurate judgment process of
evacuation is executed using the own traveling path C (Xprc[i], i=0
to 23) and the own traveling path E (Xpre[i], i=0 to 23) is
synthesized according to the result of the judgment, unnecessary
calculations according to every behavior of the preceding vehicle
can be effectively prevented from being made and as a result an
accurate calculation of the own traveling path can be
performed.
[0089] Further, the ON-OFF signal of the turn signal switch 9 and
the value of the steering wheel rotation angle enable to obtain the
final own traveling path in a natural manner reflecting driver's
intention.
[0090] Furthermore, when the own traveling path E (Xpre[i], i=0 to
23) is calculated using the own traveling path C (Xprc[i], i=0 to
23) and the own traveling path D (Xprd[i], i=0 to 23) derived from
the traveling trace of the preceding vehicle, since the possibility
of evacuation is judged not only according to the behavior of the
preceding vehicle but also according to that of the solid object
other than the preceding vehicle in the neighborhood of the
preceding vehicle, the judgment of evacuation can be made more
correctly.
[0091] The entire contents of Japanese Patent Application No.
Tokugan 2002-271906 filed Sep. 18, 2002, is incorporated herein by
reference.
[0092] While the present invention has been disclosed in terms of
the preferred embodiment in order to facilitate better
understanding of the invention, it should be appreciated that the
invention can be embodied in various ways without departing from
the principle of the invention. Therefore, the invention should be
understood to include all possible embodiments which can be
embodied without departing from the principle of the invention set
out in the appended claims.
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