JP3601458B2 - Leading vehicle tracking control device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a preceding vehicle follow-up control device for an automobile, and more particularly to a preceding vehicle follow-up control device that operates effectively when traveling in a curve section where recognition of the preceding vehicle to be followed tends to cause an error.
[0002]
[Prior art]
Conventionally, the preceding vehicle traveling on the own lane is recognized by the preceding vehicle recognition means, and the recognized preceding vehicle is measured by the distance measurement means to measure a distance between the vehicles, and a predetermined distance is determined by the travel control device. 2. Description of the Related Art There is known a preceding vehicle following control device that automatically keeps following a vehicle while keeping the same. This type of preceding vehicle following control device determines that the preceding vehicle is on the own lane and performs following control when the lateral deviation between the own vehicle and the preceding vehicle is within a predetermined value. Operates effectively when the vehicle is substantially straight, but especially in a curved section, when it is determined that the preceding vehicle has deviated from the own lane even though it is running on the own lane, or runs on another lane. A vehicle may be erroneously recognized as a preceding vehicle traveling on its own lane. Due to such erroneous recognition, there is a problem that the tracking control operation is frequently turned on and off.
[0003]
In order to solve this problem, for example, in the invention disclosed in Japanese Patent Application Laid-Open No. H10-86688, a plurality of preceding vehicles traveling ahead of the host vehicle are imaged by an imaging device, and the imaged image is displayed. The device is displayed, and on this display screen, the driver specifies the target vehicle by performing a selection operation using the input device. As a result, the vehicle can follow the vehicle to be followed even in a curved section, and the problem that the following control operation is frequently turned on and off in the curved section is solved.
[0004]
[Problems to be solved by the invention]
However, such a conventional preceding vehicle following control device has a problem that the operation is cumbersome because the driver needs to perform an operation for selecting the following vehicle from the input device every time in order to select the following vehicle. there were.
[0005]
The present invention has been made in view of the above problem, and detects a curve radius of a traveling road when traveling in a curved section, and when the curve radius is smaller than a predetermined value, that is, in a case of a tight curve. It is an object of the present invention to provide a preceding vehicle following control device that can stably follow a running section even in a curved section by locking on a preceding vehicle that travels in the vicinity of the host vehicle as a following vehicle.
[0006]
In addition, it is determined in advance that the preceding vehicle to be followed has entered a curved section from a straight road while the own vehicle is still traveling on a straight line, and the preceding vehicle is locked on as a vehicle to be followed to enable the vehicle to follow the vehicle. The purpose is to provide a vehicle tracking control device.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 of the present application recognizes a preceding vehicle traveling ahead of the host vehicle. At the same time, an own lane determination is made as to whether the preceding vehicle is within a predetermined own lane estimation range. The preceding vehicle recognition means and the traveling position of the own vehicle Or your vehicle Road shape determining means for determining a curve radius of a road ahead, and the preceding vehicle recognizing means Within the estimated range of own lane When you are in Judged The preceding vehicle as the vehicle to be followed Recognize and hold a predetermined distance from the following vehicle Performs preceding vehicle following control to follow the own vehicle. Together with , The road shape Judgment If the curve radius obtained by the means is smaller than the predetermined value ,Previous Preceding vehicle recognition means of Own lane judgment Performs lock-on processing to maintain handling as the target vehicle even if the result is negative, and holds a predetermined distance from the target vehicle Running control means for performing lock-on following control for causing the own vehicle to follow.
[0008]
According to a second aspect of the present invention, the traveling control unit may be configured to execute the road shape control during the lock-on following control. Judgment If it is determined that the curve radius determined by the means is equal to or larger than the predetermined value, the lock-on is performed. processing Is released, and the preceding vehicle following control is performed.
[0009]
According to a third aspect of the present invention, the road shape determining means includes an image capturing means for capturing an image in front of a traveling road, an image processing means for extracting a partition line from image data captured by the image capturing means, And a curve radius estimating means for estimating a curve radius of a road ahead of the own vehicle based on the partition line.
[0010]
According to a fourth aspect of the present invention, the road shape determining means detects a stationary object existing on a road side in front of the own vehicle, and the own vehicle based on the detected positional information of the stationary object. And a curve radius estimating means for estimating a curve radius of a road ahead of the vehicle.
[0011]
According to a fifth aspect of the present invention, the traveling control means is configured to determine whether a curve radius determined by the road shape determination means is equal to or larger than the predetermined value during the lock-on following control. After a predetermined time has passed since it was determined that the processing Is released, and the preceding vehicle following control is performed.
[0012]
According to a sixth aspect of the present invention, when the travel control means determines that the curve radius determined by the road shape determination means is smaller than the predetermined value, the travel control means decreases the curve radius. , Mosquito Lock on after the radius of the processing The time until the cancellation is set to be long.
[0013]
【The invention's effect】
According to the first aspect of the present invention, if the curve radius of the road at the traveling position of the own vehicle determined by the road shape determining means is smaller than a predetermined value, the road is recognized by the preceding vehicle recognition means. The obtained preceding vehicle is locked on as a target vehicle to be followed (target vehicle) to perform following travel, and thereafter, the curve radius of the road at the traveling position of the own vehicle obtained by the road shape determining means has become a predetermined value or more. In such a case, since the lock-on of the vehicle to be followed is released, the driver does not need to perform a troublesome operation, for example, even when the vehicle is traveling on a curved section.
[0014]
Also, If the curve radius of the road ahead of the own vehicle determined by the road shape determining means is smaller than a predetermined value, the preceding vehicle recognized by the preceding vehicle recognizing means is locked on as the vehicle to be followed, and then the road shape determination is performed. If the curve radius of the road ahead of the own vehicle obtained by the means is equal to or larger than a predetermined value, the lock-on is released, so that the presence of a curve section ahead of the own vehicle is recognized even when the own vehicle is traveling on a straight line. At that point, the preceding vehicle can be locked on, and the driver does not need to perform any troublesome operations.
[0015]
According to the invention described in claim 3, a partition line (white line or yellow line) drawn on the road is extracted from the image data obtained by imaging the front of the host vehicle, and the road ahead of the host vehicle is extracted based on the partition line. Since the curve radius is estimated, the curve radius can be easily estimated using a known technique.
[0016]
According to the invention described in claim 4, since the curve radius of the road is estimated from the position information of the stationary object such as the guardrail and the side wall in front of the own vehicle and the continuous road sign, for example, the partition line is not drawn. Even on a road, the radius of a curve can be accurately estimated.
[0017]
According to the invention as set forth in claim 5, when the road shape is a sharp curve, the curve section tends to be continued thereafter, and therefore, for example, a curvature change point of an S-shaped curve (from one curve to the other) At the point where the curve changes, the lock-on release is delayed for a predetermined time, so that the lock-on release is not performed even when the curvature change point is reached, and the vehicle to be followed continues to follow. On a continuous road, the setting of the lock-on and the release of the lock-on are performed alternately and frequently, whereby the control is not stabilized, and the occurrence of erroneous recognition of the vehicle to be the target vehicle to be followed can be avoided.
[0018]
According to the sixth aspect of the invention, the lock-on release delay is set such that the longer the sharper the curve, the longer the delay time, that is, the longer the lock-on release time in response to a smaller detected curve radius. Are sequentially delayed, so that the lock-on can be properly released.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0020]
<< 1st Embodiment >>
First, a first embodiment will be described. The first embodiment corresponds to the first, fifth, and sixth aspects, and detects a curve radius of a road at a traveling position of a host vehicle to lock on a target vehicle (vehicle to be followed), that is, to follow. The vehicle is fixed while traveling on a curve section, and when the vehicle exits the curve section, the lock-on is released and the control is shifted to the normal following control. The preceding vehicle following control device according to the first embodiment includes a radar device 1, a target vehicle recognition controller 2, and an inter-vehicle distance control controller 5, as shown in FIG. It is connected to a mounted vehicle speed sensor 3 and a steering angle sensor 4. The preceding vehicle following control device is activated by turning on a main switch (not shown).
[0021]
The radar device 1 is realized by a laser radar, a millimeter-wave radar, or the like. The radar device 1 recognizes a preceding vehicle, an object such as a road side wall, measures the distance and direction thereof, and detects a preceding vehicle with respect to the position of the own vehicle. Output relative position coordinates (X, Y) with respect to a plurality of objects located in front of the object.
[0022]
The target vehicle recognition controller 2 includes a CPU as a microcomputer, a RAM and a ROM as a memory, an input / output interface circuit, and the like, and based on data detected by the vehicle speed sensor 3 and the steering angle sensor 4, the current vehicle is recognized. A road shape estimating unit (road shape determining unit) 2b that calculates a curve radius of a road on which the vehicle is traveling, and the radar device 1 captures when the road shape estimating unit 2b recognizes a curve section. A lane-preceding vehicle recognizing unit 2a for recognizing a preceding vehicle that is immediately preceding the vehicle from a plurality of detected front objects, and locking the preceding vehicle recognized by the vehicle-lane preceding vehicle recognizing unit 2a during traveling in a curved section. The lock-on processing unit 2c to be activated and the vehicle locked on by the lock-on processing unit 2c are determined as the target vehicles. Configured to position data of Tsu bets vehicle from the target vehicle determining unit 2d to be outputted to the adaptive cruise control controller 5. The inter-vehicle distance control controller 5 controls the traveling of the own vehicle such that the target vehicle and the own vehicle travel while maintaining a predetermined inter-vehicle distance.
[0023]
Next, the operation of the first embodiment will be described with reference to FIGS. FIG. 2 is an explanatory diagram showing a road shape and a detection state of a preceding vehicle detected by a radar. FIG. 3 is a diagram showing a position data of a target vehicle B (see FIG. 2) to be followed by the own vehicle A (see FIG. 2). 5 is a flowchart for explaining the operation of the target vehicle recognition controller 2 for outputting to the control controller 5.
[0024]
<Signal input and calculation of curve radius>
First, when the system is started by the driver turning on the main switch (step ST100 in FIG. 3), the radar device 1 scans the front of the host vehicle and recognizes the position coordinates (Xn, Yn) of a plurality of preceding vehicles as the target vehicle. It outputs to the own lane preceding vehicle recognition part 2a of the controller 2 (step ST101). Next, upon receiving the vehicle speed signal of the own vehicle output from the vehicle speed sensor 3, the road shape estimating unit 2b calculates the speed of the own vehicle (step ST102).
[0025]
Next, the steering wheel rotation angle signal output from the steering angle sensor 4 is input to the road shape estimating unit 2b. The road shape estimating unit 2b receives inputs from the vehicle speed sensor 3 and the steering angle sensor 4 and calculates a curve radius of a road on which the host vehicle runs (step ST103). Here, the curve radius R when the steering angle of the vehicle running at the vehicle speed V is θ is given by the following equation (1).
[0026]
R = (1 + A · V ² ) · N · L / θ (1)
Here, A is a stability factor that is a value unique to the vehicle, N is the steering gear ratio, and L is the wheelbase of the vehicle.
[0027]
<Curve section determination>
Next, it is determined whether or not the value of the calculated curve radius R is smaller than a predetermined value. In this embodiment, the curve radius R is set to R = 600 m, and it is determined whether or not the curve radius of the road on which the vehicle is currently traveling is steeper than R600 m (step ST104). This curve radius can be set arbitrarily. For example, when the vehicle follows the preceding vehicle with an inter-vehicle distance of 50 m, the lateral deviation of the preceding vehicle is about 2 m in the curve of R600 m, and the direction detection accuracy by the radar and In this embodiment, the threshold value R is set to 600 m because the influence of the steering angle and the vehicle speed on the curve radius estimation accuracy increases the possibility of erroneous determination as a vehicle traveling in an adjacent lane. I have.
[0028]
<Judgment of substantially straight section>
When the curve radius calculated in the process of step ST103 is a large curve of 600 m or more (NO in step ST104), the target vehicle determining unit 2d sets a constant lane width (generally, along the calculated curve radius). (The value of about 3.5 m is often used.) The position coordinates of a plurality of objects input from the radar device 1 are referred to the own lane estimation range having a value of about 3.5 m. It is determined as a preceding vehicle of the own vehicle (step ST107).
[0029]
Then, the determined preceding vehicle in the vicinity of the own lane is registered in the target vehicle determining unit 2d as a target vehicle to be used for inter-vehicle distance control, that is, a target vehicle (step ST108). Next, returning to step ST101, the following procedures are sequentially executed.
[0030]
<Operation in curve section>
If it is determined in step ST104 that the curve is a sharp curve with a curve radius of 600 m or less (YES in step ST104), the target vehicle to be followed by the target vehicle determination unit 2d, that is, the target vehicle exists. It is determined whether or not it is (step ST109). If the target vehicle does not exist, the process returns to step ST101, and the following procedure is repeated.
[0031]
<Lock on set>
If a target vehicle exists in step ST109 (YES in step ST109), target vehicle determination section 2d determines whether lock-on is set for the target vehicle (step ST110). ). If not set (NO in step ST110), lock-on is set by lock-on processing section 2c (step ST111).
[0032]
Once set as a preceding vehicle (target vehicle) to be followed, the lock-on operates so as to maintain the handling as the target vehicle even if the position of the vehicle is out of the range of the own lane determination. .
[0033]
Next, based on the magnitude of the curve radius calculated in the process of step ST103, the time from when it is determined that the road is a substantially straight road through the curve section to when the lock-on is released is delayed. The lock-on release delay time is set (step ST112), and the preceding vehicle that has been locked on is registered in the target vehicle determination unit 2d as the target vehicle to be followed (step ST113), and the process returns to step ST101 to execute the following procedure. I do.
[0034]
<Setting the lock-on release delay time>
FIG. 4 is a graph illustrating a relationship between a curve radius and a time from when the vehicle enters a substantially straight road after passing through a curve section until the lock-on is released as a following vehicle. Considering that a sharp curve section generally passes at a low speed, the lock-on release time, that is, the lock-on release delay time is increased as the curve radius becomes smaller.
[0035]
In this embodiment, as shown in the drawing, the delay time is 10 seconds at a curve radius of 100 m and 0 second at a curve radius of 600 m. During this period, the delay time changes linearly from the curve radius of 100 m to the curve radius of 600 m. Is set.
[0036]
As described above, in general, the setting of the lock-on release delay time is such that the steeper the curve that first enters, the steeper curve tends to be continued thereafter. In this case, the curvature change point of the S-shaped curve, That is, the lock-on as the target vehicle is not immediately released on the straight road portion at the transition point from one curve to the other curve, but the lock-on is released after a predetermined delay time. The following control is stabilized by avoiding frequent setting and canceling of.
[0037]
<Continuation of lock-on>
In the process of step ST110, if the lock-on process has already been performed on the target vehicle (YES in step ST110), a process of following the same vehicle as the target vehicle is performed, and the radar device 1 detects the target vehicle. The vehicle following the same vehicle condition recognized as the target vehicle is tracked from the obtained preceding vehicle data (step ST114). The determination as to whether or not the vehicles are the same is made based on whether or not the amount of change in the X and Y coordinates and the amount of change in the relative speed of the detected object are within predetermined ranges.
[0038]
If there is a preceding vehicle that satisfies the same vehicle condition (YES in step ST114), lock-on is continued for the preceding vehicle (step ST115), and the lock-on target vehicle is set as a target vehicle to be followed. Register in the target vehicle determination unit 2d.
[0039]
<Release of lock-on>
If it is determined in the process of step ST114 that there is no preceding vehicle that matches the same vehicle condition (NO in step ST114), it is determined that the target vehicle to be followed has deviated from its own lane due to a lane change or the like. Judge and reset the registration as the target vehicle (step ST116), return to step ST101, and execute the following procedure.
[0040]
On the other hand, in the second and subsequent steps of the procedure shown in the flowchart, when it is determined that the radius calculated in step ST104 is a gentle curve of 600 m or more and that the lock-on is in the set state in step ST105, (YES in step ST105), it is determined whether or not the lock-on release delay time when the lock-on is set has elapsed (step ST106). If the lock-on release delay time has not elapsed, the process proceeds to step ST114 to continue the lock-on, and thereafter, the same procedure as described above is executed.
[0041]
FIG. 2 shows the relationship between the host vehicle A and the preceding vehicle B according to the road shape. When In FIG. 10A, the vehicle A and the preceding vehicle B are on the same straight lane, and the vehicle B is determined to be the preceding vehicle in the own lane. Note that a triangle denoted by reference numeral D1 indicates a detection range of the radar device 1.
[0042]
FIG. 2B shows the state when the vehicle enters the curve. State When two vehicles are on the same turning radius, if the preceding vehicle B exists in the horizontal field of view of the radar device 1, it is determined as the preceding vehicle in the own lane.
[0043]
FIG. 3C shows an S-shaped curve section, and when the host vehicle A has entered the curvature change point of the curve, the preceding vehicle B has already entered the next curve. In this case, since the own vehicle is on a straight line, the determination of the own lane itself is performed within the range shown by the broken line. In the illustrated case, the preceding vehicle B is within the field of view of the radar, but deviates from the assumed lane of the own lane (broken line portion). Becomes unrecognized. However, by performing the lock-on processing described above, the preceding vehicle B captured in the field of view of the radar can be handled as a target vehicle.
[0044]
In this manner, in the preceding vehicle following control device according to the first embodiment, when it is determined that the own vehicle is traveling on a curve having a curve radius equal to or smaller than the predetermined value, the preceding vehicle is controlled in front of the own vehicle. When it is determined that the traveling preceding vehicle is locked on and continues to be recognized as the target vehicle, then exits the curve, and determines that the own vehicle is traveling on a road having a curve radius equal to or more than a predetermined value (substantially straight road), Since the lock-on is released, the lock-on and the lock-on release can be performed without bothering the driver.
[0045]
In addition, since the lock-on is released after a predetermined time has elapsed after the radius of the curve is determined to be equal to or less than the predetermined value and the predetermined time has elapsed after the radius is determined to be equal to or greater than the predetermined value, when the vehicle travels on an S-shaped curve or the like, the curvature of the curve changes. In this respect, the same preceding vehicle can be kept locked on, and the vehicle can run stably. Further, since the predetermined time until the lock-on is released is set longer as the curve radius at the time of lock-on is smaller, lock-on control suitable for road conditions can be performed.
[0046]
<< 2nd Embodiment >>
Next, a second embodiment of the present invention will be described. The second embodiment corresponds to the second, third, fifth and sixth aspects. The difference from the first embodiment is that even if the own vehicle is still traveling on a straight road, the preceding vehicle is The point is that when entering the curve section, the curve radius of the curve section is determined.
[0047]
FIG. 5 is a diagram showing a system configuration of the second embodiment. In the figure, the system configuration according to the second embodiment is different from the system configuration according to the first embodiment (see FIG. 1) in that a front running path such as a CCD camera as an input sensor to the target vehicle recognition controller 2 and the like. A camera device 6 for imaging the vehicle is added. Further, as an internal function of the target vehicle recognition controller 2, an image processing unit 2e and a forward traveling road curve radius estimating unit 2f are added. Other configurations are the same.
[0048]
Next, the operation of the second embodiment will be described with reference to the schematic diagram shown in FIG. 6 and the flowchart shown in FIG. The same operation parts as those in the flowchart of FIG. 3 shown in the first embodiment are omitted.
[0049]
First, when the system is started by turning on the main switch by the driver (step ST100), similar to the first embodiment, input of radar ranging data (step S101), input of vehicle speed signal and calculation of vehicle speed (step ST102), steering Angle signal input and turning curve radius R calculation (step ST103) are performed.
[0050]
<Image data input and white line extraction>
The camera device 6 captures an image of the traveling road ahead of the host vehicle and transmits the captured data to the image processing unit 2 e of the target vehicle recognition controller 2. The image processing unit 2e receives the input of the imaging data of the front traveling road (step ST201), creates an image based on the data, and performs shading processing on the image so that only the white line (partition line) portion of the road is obtained. Is extracted.
[0051]
Since this white line image is a perspective image (see FIG. 6A) viewed from the vicinity of the driver's seat of the host vehicle, the image processing unit 2e converts the perspective image into a planar image (see FIG. 6B). (Step ST202). In the present embodiment, a continuous white line will be described as an example of a partition line, but the present invention is not limited to this, and may be applied to a partition line of another color such as a yellow line or a broken line. it can.
[0052]
<Calculation of curve radius of road ahead>
A preceding vehicle ahead on the own lane is determined by illuminating the curve radius of the own vehicle traveling path obtained from the position of the preceding vehicle detected by the distance measurement by the radar device 1 and the steering angle (step ST203). When the presence of the preceding vehicle is confirmed by this determination (YES in step ST204), the distance L to the vehicle is set as a forward curve radius calculation point (step ST205). If no preceding vehicle is detected in the process of step ST204 (NO in step ST204), the distance L is temporarily set to 50 m (step ST206). In this provisional setting, normally, the distance to the preceding vehicle being followed by the preceding vehicle following control is set to about 2 seconds between vehicles, so the inter-vehicle distance of about 50 m to the preceding vehicle being followed at 100 km / h. Therefore, the target point distance L for estimating the curve radius is set near the target point distance L.
[0053]
As shown in FIG. 6C, the preceding vehicle traveling road curve radius estimating unit 2f shown in FIG. 5 uses the distance L to the preceding vehicle or the temporarily set target on the white line E1 extracted by the image processing unit 2e. A tangent line E2 is set at a point (point P1 in FIG. 6C) corresponding to the distance L, and the road inclination θ of the preceding vehicle position with respect to the own vehicle is calculated (step ST207). The curve radius R is calculated from the relationship between the distance L and the inclination angle θ by the following equation (2) (step ST208).
R = L / sin θ (2)
After the curve radius R is obtained, the procedure thereafter is the same as in the first embodiment, and the procedure from step ST104 shown in FIG. 3 is executed. The description thereof is the same as that of the above-described first embodiment, and will not be repeated.
[0054]
As described above, according to the preceding vehicle following control device according to the second embodiment, the camera device 6 captures an image of the front of the own vehicle, performs image processing on the image, extracts a partition line, and extracts the partition line. Based on this, the curve radius of the road ahead of the vehicle is calculated. Therefore, since the preceding vehicle can be locked on when the existence of the curve section ahead of the own vehicle is recognized, the lock-on control can be performed more reliably.
[0055]
<< 3rd Embodiment >>
Next, a third embodiment will be described. The third embodiment corresponds to the second, fourth, fifth, and sixth aspects. Similar to the second embodiment, even when the own vehicle is still traveling on a straight road, the preceding vehicle is in a curved section. When the vehicle enters, the radius of the curve is determined.
[0056]
FIG. 8 is a diagram illustrating a system configuration according to the third embodiment. In the figure, a radar device 1 used in the third embodiment is a millimeter wave radar device capable of measuring position coordinates (Xn, Yn) and relative speed Vrn (n = 1 to 10) for a plurality of targets (for example, 10 targets). Is used.
[0057]
Regarding the target vehicle recognition controller 2, in the system configuration according to the first embodiment shown in FIG. 1, the position coordinates of a plurality of stationary objects are calculated from the position coordinate information and the relative speed information about a plurality of forward objects output from the radar device 1. A stationary object recognizing unit 2g to be recognized and a forward road shape estimating unit 2h for calculating a curve radius of a road near the stationary object from the arrangement information of the plural stationary objects obtained by the stationary object recognizing unit 2g are added. The output of the forward road shape estimating unit 2h is supplied to the lock-on processing unit 2c, and the lock-on process for the preceding vehicle is performed.
[0058]
The rest of the system configuration is the same as the system configuration in the first embodiment (see FIG. 1), and a description thereof will be omitted.
[0059]
Next, the operation of the third embodiment will be described. FIG. 11 is a flowchart for explaining the operation of the third embodiment, and portions common to the first embodiment are denoted by the same step numbers.
[0060]
First, when the system is started by turning on the main switch by the driver (step ST100), distance measurement data by the radar device 1 is input (step ST101). The obtained distance measurement data includes, for example, a moving object such as a preceding vehicle and a stationary object such as a side wall.
[0061]
Next, the vehicle speed signal from the vehicle speed sensor 3 is input, and the vehicle speed Vf of the own vehicle is calculated (step ST102).
[0062]
<Detection of a stationary object along the curve of the road ahead>
It is determined whether or not there is a group of stationary objects from among the plurality of objects detected by the radar device 1 (step ST120). FIG. 12 shows a more specific operation of step ST120. This processing procedure will be described later.
[0063]
FIG. 10 is a diagram showing a situation in which the radar apparatus 1 detects a forward object. FIG. 10A shows a curve provided with a guardrail and a side wall at the shoulder of the road ahead of the host vehicle A, and will enter this curve section. The state in which the preceding vehicle B is running is shown. The triangle protruding in front of the host vehicle A indicates the horizontal field of view of the radar.
[0064]
FIG. 10B shows the position coordinates of the object detected by the radar device 1. Among them, a target whose relative speed Vrn is substantially equal to the vehicle speed Vf of the host vehicle is treated as a stationary object. The square indicated by reference F1 indicates a stationary object, and the triangle indicated by reference F2 indicates a moving object. In this embodiment, as shown in the figure, the eight stationary objects F1 along the curved section of the road are recognized by the radar signals reflected by the guardrails and the side walls, and the preceding vehicle B is recognized as the moving object F2. An example is shown.
[0065]
In step ST121 of FIG. 12, it is determined whether the number of the detected stationary objects F1 is equal to or greater than a predetermined number. Here, the minimum number of two required to draw a straight line is a predetermined number. If there are two or more stationary objects F1 (YES in step ST121), the objects in which the positions of the stationary objects F1 are significantly separated from each other are excluded (step ST122). This processing is performed in order to prevent an error in calculating the radius of the curve from increasing when detecting reflection from an object other than the object along the curve of the road.
[0066]
After performing the process of removing abnormal values, it is determined whether or not a group of the stationary object F1 remains (step ST123). If it remains (YES in step ST123), the stopped object group is registered in the stopped object recognizing unit 2g (see FIG. 8) for use in subsequent curve radius calculation (step ST124). This is because it has been experimentally confirmed that the stationary objects along the curve are detected so as to be arranged on a straight line substantially tangent to the curve.
[0067]
On the other hand, when the stop object F1 cannot be detected by the predetermined number or more (NO in step ST121), the stop object F1 is treated as not detecting the stop object group (step ST120 in FIG. 11).
[0068]
<Calculation of curve radius of road ahead>
Next, a method of calculating a curve radius of a forward road based on an array of stationary objects when a stationary object group is detected will be described with reference to the flowchart of FIG. 13 and FIGS. 9, 10C, and 10D. The description will be made based on the explanatory diagram shown in () (step ST300).
[0069]
First, an object S1 (x1, y1) whose X coordinate is the leftmost when viewed from the own vehicle in the stopped object group is determined (step ST301, see FIG. 10C). Next, the rightmost stationary object S2 (x2, y2) in the same group is determined (step ST302). A straight line LS connecting the two points S1 and S2 is set (step ST303, see FIG. 10D). Next, an extension straight line LV with respect to the straight traveling direction of the own vehicle is set (step ST304). The distance L from the position P0 of the host vehicle to the intersection P2 of the two straight lines LS and LV is obtained (step ST305). The distance L is given by the following equation (3) from two coordinate points.
[0070]
L = y1-x1 (y2-y1) / (x2-x1) (3)
Further, an angle φ at which the straight lines LS and LV intersect is calculated (step ST306). The angle φ is given by the following equation (4) (see FIG. 10D).
φ = tan ^-1 {(X2-x1 / (y2-y1)}} (4)
Finally, a curve radius R at the arc P2 is calculated from the distance L and the angle φ obtained above. Since the angle φ is an angle formed between the tangent line LS at the point P2 and the straight line LV drawn with respect to the point P2 at the vehicle position P0, the curve radius R at the point P2 is given by the following equation (5) (FIG. 9).
[0071]
R = L / sinφ (5)
When the curve radius R is calculated, the process returns to the main process from step ST300, and it is determined whether the curve radius R is larger or smaller than a predetermined value 600m (step ST104), thereby determining entry into the curve section.
[0072]
<Calculation of turning radius of own vehicle>
On the other hand, when the stationary object group is not detected by the radar device 1 in step ST120 (FIG. 11), it is not possible to estimate the forward curve radius based on the array of stationary objects, so the turning curve radius is calculated from the steering angle of the host vehicle. R is obtained (step ST103), and is used to determine whether or not a curve section is present.
[0073]
<Lock on set for the preceding vehicle>
The subsequent operation (the operation after step ST104 in FIG. 11) is the same as in the first embodiment, and the curve section is determined based on the forward curve radius or the own vehicle turning curve radius obtained from the array of stationary objects. If a preceding vehicle is present on the own lane when this is done, lock-on is set for that vehicle. Thereafter, the operation is the same as that of the first embodiment.
[0074]
As described above, in the preceding vehicle following control device according to the third embodiment, even when the own vehicle is still traveling on a straight road, the size of the curve existing in front of the preceding vehicle (curve) Radius) can be determined, and the preceding vehicle can be locked on immediately when the preceding vehicle starts to enter the curve, so that the target vehicle can be stably recognized before approaching the curve section. Further, even on a road on which no partition line is drawn, the road shape can be estimated based on the position information of the stationary object existing on the road side.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a preceding vehicle following control device according to a first embodiment of the present invention.
FIGS. 2A and 2B are diagrams showing a road shape on which a vehicle travels and a radar detection state of a preceding vehicle, wherein FIG. 2A shows a case where the road is straight, FIG. 2B shows a case where the road is curved, and FIG. This shows the case of an S character.
FIG. 3 is a flowchart illustrating an operation of the preceding vehicle following control device according to the first embodiment.
FIG. 4 is a characteristic diagram showing a relationship between a curve radius and a lock-on release delay time.
FIG. 5 is a block diagram showing a configuration of a preceding vehicle following control device according to a second embodiment of the present invention.
FIGS. 6A and 6B are explanatory diagrams for determining a curve radius of a road ahead by image processing, wherein FIG. 6A is an original image, FIG. 6B is a plan view image, and FIG. It is.
FIG. 7 is a flowchart showing an operation of the preceding vehicle following control device according to the second embodiment.
FIG. 8 is a block diagram illustrating a configuration of a preceding vehicle following control device according to a third embodiment of the present invention.
FIG. 9 is an explanatory diagram for determining a curve radius ahead of a road based on an object stopped ahead.
FIG. 10 is an explanatory diagram when a curve radius of a road ahead is calculated based on a detection state of a forward object by the radar device and a result of the detection.
FIG. 11 is a flowchart illustrating an operation of the preceding vehicle following control device according to the third embodiment.
FIG. 12 is a flowchart showing details of the process of step ST120 in the flowchart shown in FIG. 11;
FIG. 13 is a flowchart showing details of the processing of step ST300 in the flowchart shown in FIG. 11;
[Explanation of symbols]
1 radar equipment
2 Target car recognition controller
2a Self-lane preceding vehicle recognition unit
2b (own vehicle) road shape estimation unit
2c Lock-on processing unit
2d target car decision unit
2e Image processing unit
2f Curve radius estimator for road ahead
2g Stopping object recognition unit
2h Forward road shape estimation unit
3 Vehicle speed sensor
4 Steering angle sensor
5 Inter-vehicle distance control controller

Claims (6)

Preceding vehicle recognition means for recognizing a preceding vehicle traveling ahead of the own vehicle and determining whether or not the preceding vehicle is within a predetermined own lane estimation range ;
Road shape determining means for determining a traveling position of the own vehicle, or a curve radius of a road in front of the own vehicle ,
A preceding vehicle that recognizes the preceding vehicle determined to be within the own lane estimation range in the own lane determination of the preceding vehicle recognition means as the following vehicle, and keeps a predetermined distance from the following vehicle to follow the own vehicle. follow-up control lines Utotomoni, the when the road shape determining means at sought curve radius is smaller than a predetermined value, the handling of the follow-up target vehicle be traveling lane determination becomes not before Symbol preceding vehicle recognizing means Traveling control means for performing lock-on processing for maintaining, and performing lock-on tracking control for tracking the own vehicle while maintaining a predetermined distance from the tracking target vehicle ;
A preceding vehicle following control device, comprising: The traveling control means cancels the lock-on process if the curve radius determined by the road shape determination means is determined to be equal to or larger than the predetermined value during the lock-on following control, and performs the preceding vehicle following control. The preceding vehicle follow-up control device according to claim 1, wherein: The road shape determining unit includes an image capturing unit that captures an image of the front of the traveling road, an image processing unit that extracts a partition line from image data captured by the image capturing unit, and an image processing unit that extracts a partition line based on the partition line. The preceding vehicle following control device according to claim 1 or 2, further comprising a curve radius estimating means for estimating a curve radius of the road. The road shape determining means detects a stationary object existing on the road side ahead of the own vehicle, and estimates a curve radius of a road ahead of the own vehicle based on the position information of the detected stationary object. 3. The preceding vehicle following control device according to claim 1, further comprising: a curve radius estimating unit that performs the following. The travel control means, when the curve radius determined by the road shape determination means is determined to be equal to or more than the predetermined value during the lock-on following control, after it is determined that the curve radius is equal to or more than the predetermined value The preceding vehicle following control device according to any one of claims 1 to 4, wherein the lock-on process is released after a predetermined time has elapsed, and the preceding vehicle following control is performed. The running control means, when the road shape determining means at sought curve radius is determined to be smaller than the predetermined value, as the curve radius is small, mosquitoes over blanking radius from equal to or greater than a predetermined value The preceding vehicle follow-up control device according to claim 5, wherein a time until the lock-on process is released is set long.

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