JP6325365B2 - Steering support control device - Google Patents

Description

  The present invention relates to a technical field of a steering assist control device mounted on an automobile.

JP2013-246640A

As a steering support function, a lane keeping function is known in which a vehicle recognizes a lane and continuously supports a steering operation so as to travel in the center.
As this steering support, a system for recognizing a lane by an in-vehicle camera and determining a timing for operating the lane and controlling the steering based on the lane has been put into practical use. The “lane” is used to mean a so-called white line that defines a travel path (lane).
Patent Document 1 discloses a technique for detecting left and right lanes and a pedestrian crossing of an own vehicle from an image acquired by an in-vehicle camera, and detecting an intersection or a branch junction from these.

Regarding the steering assist function, the following inconveniences may occur at intersections due to lane breaks and the presence of various white lines such as pedestrian crossings.
First, since it is difficult to properly recognize the presence or absence of a lane, unnecessary operations based on misrecognition may occur. Normally, the steering assist function operates in a state where the lane is properly recognized, and the function is stopped when the lane cannot be recognized. If the steering assist function is activated when a vehicle other than a lane that defines a lane at an intersection where there are many white lines on the road surface is mistakenly recognized as a lane, an inappropriate assist operation may be performed.

In addition, the steering assist function is activated / stopped when the lane is recognized, but switching between activation / stopping is particularly likely to occur within an intersection, and the driver feels there is no sense of unity in the operation / stopping of the steering assist function, The state of the steering assist function is difficult to understand. In other words, due to instability of lane recognition, the operation and stop timing of the steering assist function varies within the intersection, and hunting is likely to occur. In addition, when operating immediately before the intersection, the operation may be canceled immediately after entering the intersection.
For these reasons, the driver may feel unstable or bothered.

  Therefore, the present invention has an object to reduce unnecessary operations at the intersection, annoyance felt by the driver, and the like by performing control according to the situation at the intersection with respect to the steering assist function.

First, a steering assist control device according to the present invention includes an imaging unit that obtains a captured image obtained by imaging the front of the host vehicle, an image processing unit that determines an operating condition of a steering assist function using the captured image, A steering support control unit that performs steering support control based on a determination result of one or a plurality of predetermined operation conditions including at least the operation condition determined by the image processing unit, wherein the image processing unit includes the own vehicle This is a support non-execution intersection that stops the steering support function using the detection result of the pedestrian crossing from the captured image and the detection result of the non-existence distance of the lane at the timing immediately before the intersection that is determined to be immediately before entering the intersection. It is determined whether or not, and the operation condition reflecting the determination result is determined.
In an intersection, the accuracy of lane recognition based on captured images decreases due to various factors. Therefore, it is conceivable to stop the steering support function at the intersection, but the actual intersection varies depending on its size and the presence or absence of a pedestrian crossing, so it is not optimal to stop the steering support function at the intersection. . Therefore, it is determined whether the intersection is a non-supporting intersection that stops the steering support function using the detection result of the pedestrian crossing and the detection result of the non-existence distance of the lane. The non-existence distance of the lane is a distance at which the lane is interrupted, and is a value representing the width of the intersection.

Secondly, in the steering assist control device according to the present invention described above, the image processing unit is in a lane when a pedestrian crossing is detected at the timing immediately before the intersection and the steering assist function is in operation. If the non-existence distance is equal to or greater than the predetermined distance, it is determined that the intersection is a support non-execution intersection, and the processing for suppressing the return of the operation of the steering support function is performed. When the support function is stopped, it is desirable to perform processing for suppressing the return of the operation of the steering support function regardless of the non-existence distance of the lane.
If it is detected that the lane is interrupted, if a pedestrian crossing is detected, the location is likely to be an intersection. For this reason, it is preferable to continuously stop the steering assist function at a wide intersection where the non-existence distance of the lane is long to avoid erroneous recognition of the lane. Therefore, if the steering support function is in operation immediately before entering the intersection, the steering support function is stopped and the return is suppressed so that the steering support function does not return to the operating state in the intersection. If the steering support function is stopped immediately before entering the intersection, the return is suppressed in the stopped state so that the steering support function does not return within the intersection.

Third, in the steering assist control device according to the present invention described above, when the pedestrian crossing is not detected and the steering assist function is operating at the timing immediately before the intersection, If the non-existence distance of the lane is greater than or equal to the predetermined distance, it is determined as a support non-execution intersection and a process of suppressing the operation return of the steering support function is performed, and a crosswalk is not detected at the timing immediately before the intersection, When the steering assist function is stopped, it is desirable to perform a process for suppressing the return of the operation of the steering assist function if the non-existence distance of the lane is equal to or greater than a predetermined distance.
If a lane break is detected but a pedestrian crossing is not detected, the location may not be an intersection. However, if the non-existence distance of the lane is longer than the predetermined distance, it may be considered as an intersection, and the lane recognition becomes unstable, so it is appropriate to stop the steering assistance to avoid malfunction due to lane misrecognition It is.
Based on this concept, if the steering support function is in operation immediately before entering the intersection, the steering support function is stopped and the return is suppressed so that the steering support function does not return within the intersection.
If the steering assist function is stopped immediately before entering the intersection, if the non-existence distance of the lane is equal to or greater than the predetermined distance and the possibility of the intersection is large, the return is suppressed in the stopped state. However, if the non-existence distance of the lane is less than the predetermined distance, there is a high possibility that the lane is not an intersection, and the lane ahead is observable, so the possibility that the lane recognition becomes unstable is small. Therefore, the return is not suppressed.

Fourth, in the steering assist control device according to the present invention described above, the image processing unit is in a lane when a pedestrian crossing is detected at the timing immediately before the intersection and the steering assist function is in operation. If the non-existence distance of the vehicle is less than the predetermined distance, it is not determined that the intersection does not support assistance. For example, it is desirable not to make a determination as a support non-execution intersection.
When a lane break is detected and an intersection is estimated due to the presence of a pedestrian crossing, there is little possibility of misrecognition at a small intersection where the lane nonexistence distance is less than a predetermined distance. Enable support.
If there is a possibility that there is no pedestrian crossing and it is not an intersection even if the lane is interrupted, the steering assist function is activated at a small intersection where the non-existence distance of the lane is less than the predetermined distance because the lane is less likely to be recognized incorrectly. If it is in the middle, the steering assistance can be performed as it is, and the steering assistance function can be operated even when the steering assistance is stopped.

Fifth, in the above-described steering assist control device according to the present invention, the image processing unit does not satisfy the operating condition of the steering assist function for a certain period of time as a process of suppressing the return of the operation of the steering assist function. It is desirable to perform processing.
The fixed time is, for example, a time necessary for not returning until the vehicle passes through the intersection.

  According to the present invention, it is possible to reduce or avoid the occurrence of hunting or unnecessary operation of a steering assist function in an intersection, and to reduce the annoyance and anxiety felt by the driver by improving the stability of the steering assist function. Can do.

It is a block diagram for demonstrating the steering assistance control apparatus of embodiment of this invention. It is explanatory drawing of various intersection situations. It is explanatory drawing of various intersection situations. It is explanatory drawing of the operation state of the steering assistance function in the intersection of embodiment. It is a flowchart of a process of the steering assistance control part of embodiment. It is a flowchart of a process of the image processing part of an embodiment. It is a flowchart of the intersection situation determination process of embodiment. It is a flowchart of the lane condition information output process of embodiment.

Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 shows a main part of an in-vehicle system including the steering assist control device of the embodiment.
The steering assist control device according to the embodiment includes an imaging unit 10 and a steering assist control unit 20. Further, FIG. 1 shows a steering mechanism 30 and a motor drive unit 21 as targets for which the steering support control is performed by this steering support control device. As sensors used for the steering support control, a vehicle speed sensor 15, a yaw rate sensor 16, A lateral acceleration sensor 17 is shown. Further, a display unit 22 and a sound generation unit 23 are shown as related parts of steering assist control.

The imaging unit 10 includes two imaging units 11 </ b> L and 11 </ b> R and an image processing unit 12 that are installed in a vehicle so as to be able to capture the traveling direction (front).
The imaging units 11L and 11R are arranged at a predetermined interval in the vehicle width direction, for example, in the vicinity of the upper part of the windshield of the host vehicle so that distance measurement by a so-called stereo method is possible. The optical axes of the imaging units 11L and 11R are parallel, and the focal lengths are the same. Also, the frame periods are synchronized and the frame rates are the same. The number of pixels of the image sensor is, for example, about 1280 × 960.

  The electrical signals (captured image signals) obtained by the image sensors of the imaging units 11L and 11R are each A / D converted into digital image signals (captured image data) representing luminance values with a predetermined gradation in pixel units. . The captured image data is, for example, color image data. Accordingly, three data (luminance values) of R (red), G (green), and B (blue) are obtained for each pixel. The gradation of the luminance value is, for example, 256 gradations.

The image processing unit 12 includes a microcomputer having, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory) as a work area, and various types of programs according to programs stored in the ROM. Execute the process.
The image processing unit 12 stores each frame image data as captured image data obtained by the imaging units 11L and 11R imaging the front of the host vehicle in the internal memory. Then, based on the two captured image data as each frame, various processes for recognizing an object existing in front of the vehicle as an external environment are executed. For example, a three-dimensional object such as a preceding vehicle or an obstacle is recognized, but lane recognition and pedestrian crossing recognition are particularly performed with respect to the processing of this embodiment.

The processing of the captured image data in the image processing unit 12 is performed as follows, for example. First, the image processing unit 12 obtains distance information from a corresponding position shift amount with respect to a set of images in the traveling direction of the host vehicle (images of each frame) captured by the imaging units 11L and 11R. Generate an image.
In the recognition of the lane (white line), the image processing unit 12 evaluates the luminance change of the pixels in the width direction of the road because the lane has higher luminance than the road surface, and the left and right lane candidate points on the image plane Is specified on the image plane. The position (x, y, z) of the lane candidate point in the real space is known based on the position (i, j) on the image plane and the parallax (that is, distance information) calculated with respect to this position. It is calculated by the coordinate conversion formula. The coordinate system of the real space set based on the position of the host vehicle has, for example, the road surface directly below the center of the right imaging unit 11R as the origin, the vehicle width direction as the x axis, the vehicle height direction as the y axis, and the vehicle length. The direction is defined as the z-axis. The lane candidate points converted into the coordinate system of the real space are grouped, for example, for each point sequence close to each other, and approximated to a quadratic curve (lane approximation line) using a least square method or the like. Then, the image processing unit 12 estimates the own vehicle traveling path based on the left and right lanes extending in front of the own vehicle.

  Similarly, the recognition of a pedestrian crossing can be realized by evaluating the luminance change of pixels in the width direction of the road. In particular, in the case of a pedestrian crossing, the presence of a pedestrian crossing can be recognized by detecting a state in which the change in shading is regularly repeated in the width direction.

  In the recognition of the side wall and the three-dimensional object data, the image processing unit 12 compares the data on the distance image with a frame (window) such as the three-dimensional side wall data and the three-dimensional object data stored in advance. In addition to extracting side wall data such as guardrails and curbs extending along the road, the three-dimensional objects are classified and extracted as other three-dimensional objects such as bicycles, two-wheeled vehicles, pedestrians, and power poles. In the extraction of the three-dimensional object data, the image processing unit 12 calculates the relative speed with the own vehicle from the rate of temporal change in the distance (relative distance) to each own vehicle, and adds the relative speed and the own vehicle speed. To calculate the speed of each three-dimensional object. At this time, the three-dimensional object classified as a vehicle has a forward direction of the own vehicle as positive from the speed, a vehicle having a speed of approximately 0 is a stopped vehicle, and a speed is positive (a vehicle traveling in the same direction as the own vehicle). A vehicle closest to the host vehicle is recognized as a preceding vehicle, and a vehicle with a negative speed (a vehicle coming toward the host vehicle) is recognized as an oncoming vehicle.

The above-described image recognition results such as a three-dimensional object, a lane, and a pedestrian crossing are used for various driving support controls. For example, inter-vehicle distance control and collision avoidance control.
Regarding the steering assist function of the present embodiment, detected lane data (including the own vehicle traveling path, etc.), side walls data such as guardrails, curbs, etc. existing along the road, and solid object data (type, distance, Each data such as speed, relative speed with respect to the host vehicle, and preceding vehicle information is input to the steering assist control unit 20.
Furthermore, the image processing unit 12 also determines the operating condition of the steering assist function as will be described later, and supplies the determination result to the steering assist control unit 20 as well.

  The steering support control unit 20 performs steering support such as automatic steering control based on the above-described input signals. That is, the steering assist control unit 20 sets the steering angle independently of the driver based on the lane ahead of the host vehicle, for example, to maintain the host vehicle at the center of the host vehicle traveling path, Further, it is possible to perform steering support such as lane departure control for preventing the departure of the own vehicle from the own vehicle route (deviation of the own vehicle with respect to the white line defining the own vehicle traveling route).

  The steering assist control unit 20 determines operating conditions of various steering assist functions, and executes steering assist control when the operating conditions are satisfied. Whether or not the steering assist function is operable is determined based on the operation information SD of the driver, information from the image processing unit 12, information from each sensor, and the like. Details will be described later. Here, the operation information SD of the driver comprehensively indicates operation information such as an on / off operation of an ACC (Adaptive Cruise Control) switch or a steering assist execution switch.

  For example, a vehicle speed sensor 15 that detects a vehicle speed, a yaw rate sensor 16 that detects a yaw rate, a lateral acceleration sensor 17 that detects a lateral acceleration, and the like are connected to the steering assist control unit 20 and the image processing unit 12.

For example, the steering mechanism 30 that is a target of the steering assist control is configured as follows. In this example, the steering mechanism 30 is shown as an electric power steering device in which the steering angle can be set independently of the driver input.
In the steering mechanism 30, a steering shaft 32 is rotatably supported on a body frame (not shown) via a steering column 33. One end of the steering shaft 32 extends toward the driver's seat, and a steering wheel 34 is attached to one end of the steering shaft 32. The other end of the steering shaft 32 extends to the engine room side, and a pinion shaft 35 is connected to the other end of the steering shaft 32.
A steering gear box 36 extending in the vehicle width direction is disposed in the engine room, and a rack shaft 37 is inserted into and supported by the steering gear box 36 so as to be reciprocally movable. A rack (not shown) is provided in the middle of the rack shaft 37, and a rackion and pinion type steering gear mechanism is formed by engaging a pinion (not shown) provided on the pinion shaft 35 with the rack. It is configured.

  Further, both left and right ends of the rack shaft 37 protrude from the steering gear box 36, and a front knuckle 39 is connected to the end of the rack shaft 37 via a tie rod 38. The front knuckle 39 rotatably supports left and right wheels 40L and 40R as steering wheels, and is supported by a vehicle body frame via a king pin (not shown) so as to be continuously hit. Accordingly, when the steering wheel 34 is operated to rotate the steering shaft 32 and the pinion shaft 35, the rack shaft 37 moves in the left-right direction by the rotation of the pinion shaft 35, and the front knuckle 39 is moved to the king pin (not shown). And the left and right wheels 40L, 40R are steered in the left-right direction.

  An electric motor 42 is connected to the pinion shaft 35 via an assist transmission mechanism 41. The electric motor 42 assists the steering torque applied to the steering wheel 34 and provides a set steering angle. Such a steering torque is added. The electric motor 42 is driven via the motor drive unit 21 so as to have a steering torque (control amount) set by the steering assist control unit 20.

The steering assist function includes such a steering torque assist function, but also provides a warning about lane departure on the road and notification regarding steering assist. Therefore, as shown in the figure, the steering assist control unit 20 supplies display information and sound generation instruction information to the display unit 22 and the sound generation unit 23.
The display unit 22 comprehensively shows, for example, a display control unit and a display device using a microcomputer. The display device is, for example, various meters such as a speedometer and a tachometer provided in a meter panel installed in front of the driver, MFD (Multi Function Display), and other devices for presenting information to the driver. With respect to the steering support function, the display unit 22 displays a warning display or a display for presenting the driver with the operation support / stop of the steering support.
The sound generation unit 23 comprehensively shows a sound generation control unit such as a microcomputer and a sound generation device such as an amplifier / speaker. As for the steering assist function, the sound generator 23 outputs a warning sound and a notification sound that informs the driver of the operation / stop of the steering assist.

An operation example related to the steering assist control according to the embodiment having the above-described configuration will be described.
2 and 3 show various road conditions. First, FIG. 2 schematically shows a situation where a pedestrian crossing 95 exists. 2A shows a case where the left and right lanes 90 of the host vehicle 100 are interrupted, FIG. 2B shows a case where one of the left and right lanes 90 of the host vehicle 100 is interrupted, and FIG. If not.
Here, FIGS. 2A and 2B are cases where the image processing unit 12 estimates a relatively small intersection. The size of the intersection depends on the length of the non-existence distance DL of the lane 90. The non-existence distance DL of the lane 90 is a distance between the break position PC1 of the left and right lane 90 of the host vehicle 100 and the start position PC2 of the lane 90 ahead. If the non-existence distance DL is greater than or equal to a predetermined distance, it is estimated that the intersection is large, and if it is less than the predetermined distance, it is estimated that the intersection is small. The predetermined distance is, for example, 20 to 30 m. For example, this may be set as a distance that enables stable image recognition by the imaging unit 10.
FIG. 2C shows a place where the lane 90 is not interrupted but is estimated to be an intersection due to the pedestrian crossing 95.

  2D shows a case where the left and right lanes 90 of the host vehicle 100 are interrupted, FIG. 2E shows a case where one of the left and right lanes 90 of the host vehicle 100 is interrupted, and FIG. Is the case where there is no interruption. Among these, FIG. 2D and FIG. 2E are places where the nonexistence distance DL is estimated to be a large intersection when the distance is not less than a predetermined distance. FIG. 2F is a place where the lane 90 is not interrupted but is estimated to be an intersection due to the pedestrian crossing 95.

  On the other hand, FIG. 3 illustrates a place where the pedestrian crossing 95 does not exist. Each of FIGS. 3A to 3E is a case where there is no pedestrian crossing 95 in the lane state similar to FIGS. 2A to 2E.

Usually, there is a break in the lane 90 at an intersection such as a crossroad or a T-shaped road. Further, when there is a pedestrian crossing 95, the possibility of an intersection is high, or even if it is not actually an intersection, it can be said that the lane recognition may be unstable due to the pedestrian crossing 95.
In the present embodiment, the steering assist control is optimized in various intersection situations as shown in FIGS. 2 and 3 (road situations that are not necessarily intersections but may be intersections). in particular,
・ Suppress the switching / hunting of steering assist function operation / stop in the intersection ・ Stop the steering support function to prevent malfunction at intersections where there is a high possibility of lane misrecognition ・ Determine whether to operate / stop at the intersection Based on the idea of unifying the timing, the operating state of the steering assist function is set. Note that the “intersection” does not mean whether or not it is actually an intersection, but refers to a place that is recognized as a possible intersection in image processing.

FIG. 4 shows the transition of the operating state of the steering assist function within the intersection in each case. ○ indicates the steering assist operating state, and x indicates the steering assist stopped state. “Both sides” and “One side” for a lane in the table are different depending on whether the lane is interrupted on either side or one side. In this example, even if there is a break on one side, it is treated in the same way as a break on both sides, and there is practically no difference in control. “Large interval” and “small interval” are different whether the non-existence distance DL of the lane 90 is greater than or less than a predetermined value.
The pre-entry operating state is a distinction between whether or not the steering assist function is operating in a state immediately before entering the intersection (operating / stopping).

FIG. 4A shows a case where a pedestrian crossing 95 is detected assuming a place as shown in FIG.
When the pedestrian crossing 95 is detected, if the steering support function is stopped immediately before approaching the intersection (hereinafter simply referred to as “stopping”), the operation state is not restored within the intersection (return suppression). Therefore, regardless of the state of the lane 90, the steering assist function is stopped in the intersection.
On the other hand, if the steering assist function is in operation immediately before entering the intersection (hereinafter simply referred to as “in operation”), the vehicle is stopped at the intersection with a large interval and the return is suppressed. However, at intersections with small intervals, the operation is continued without stopping. This is because an intersection with a small interval can be recognized by the forward lane 90, and the stability of lane recognition is relatively high.
2C and 2F, when there is no break in the lane 90, the possibility of an intersection is recognized by the detection of the pedestrian crossing 95, but since the stability of the lane recognition is relatively high, it is operating immediately before entering the intersection. If so, the operation may be continued as it is. However, since it cannot be said that there is a possibility of misrecognition due to the influence of the pedestrian crossing 95, if the vehicle is stopped immediately before the intersection, the return is suppressed so that the vehicle is stopped. In this case, there may be an idea that no return suppression is performed.

FIG. 4B shows a case where a place where the pedestrian crossing 95 as shown in FIG. 3 is not detected is assumed.
In the case of an intersection without a pedestrian crossing 95, if it is stopped immediately before entering the intersection, the return is suppressed when the interval is large. When the interval is small, there is a high possibility that it is not an intersection, and the forward lane 90 can be recognized, and the stability of the lane recognition is relatively high. That is, if the lane recognition can be normally performed, the steering assist function is activated.
In the case of an intersection where there is no pedestrian crossing 95, if it is operating immediately before entering the intersection, if the distance is large, the vehicle is stopped and the return is suppressed. When the interval is small, there is a high possibility that it is not an intersection, and the forward lane 90 can be recognized, and the stability of the lane recognition is relatively high, so the operation state is continued.
In the case of FIG. 3C in which the pedestrian crossing 95 is not detected and the lane 90 is not interrupted, the possibility of an intersection is very low. In other words, it is a normal road. Therefore, the operation stop and the return suppression are not particularly performed according to the intersection state, the operation is continued as long as it is in operation, and it operates according to the lane recognition even under the stop (due to other operation conditions described later).

For example, processing for realizing the operation / stop of the steering assist function according to the above-described intersection situation will be described below.
First, FIG. 5 shows a steering assist operation condition process of the steering assist controller 20. The steering support control unit 20 determines the operation / stop of the steering support function by the processing of FIG.
In step S101, the steering assist control unit 20 confirms whether or not the ACC is on based on the operation information SD, that is, whether or not the driver assist mode is instructed.
In step S102, the steering support control unit 20 confirms whether or not the steering support is turned on by the operation information SD, that is, whether or not the driver is instructed to perform the steering support.

In step S103, the steering assist control unit 20 confirms whether the vehicle speed condition is OK. For example, a condition is set for the steering assist function to be activated when the vehicle speed is equal to or higher than a certain speed (for example, when the vehicle speed is 65 km / h or higher). The steering assist control unit 20 determines from the information of the vehicle speed sensor 15 whether or not the vehicle is currently at a certain speed or higher. Note that the image processing unit 12 may determine the vehicle speed condition from the information of the vehicle speed sensor 15 and the steering assist control unit 20 may confirm the determination result.
In step S104, the steering assist control unit 20 confirms whether the lateral acceleration condition is OK. For example, the steering assist function is set to operate when the lateral acceleration is within a certain range (for example, within 2.0 G). The steering assist control unit 20 determines from the information of the lateral acceleration sensor 17 whether or not the current lateral acceleration is within a certain range. Alternatively, the image processing unit 12 may determine the lateral acceleration condition from the information of the lateral acceleration sensor 17, and the steering assist control unit 20 may confirm the determination result.

In step S105, the steering assist control unit 20 confirms whether the lane condition is OK. In this example, the lane condition determination result from the image processing unit 12 is referred to. The “lane condition” here is used as a comprehensive term for the following conditions.
-Lane recognition conditions: Lanes can be recognized by image processing.
-Curvature condition: Curvature curve curvature is within a certain range.
Road width condition: The road width is within a predetermined range (for example, 3 m or more and less than 4 m).
・ Operating conditions depending on the situation of the intersection: Whether the operation is possible according to the situation of each intersection as shown in FIG.

  When the image processing unit 12 determines that the lane recognition condition, the curvature condition, the road width condition, and the operation condition based on the intersection situation are all satisfied and can be operated, the image processing unit 12 transmits information indicating the lane condition OK (lane condition satisfaction). On the other hand, if any one of the conditions is not satisfied, or if all of the conditions are satisfied and the return is suppressed, information indicating the lane condition NG (lane condition not satisfied) is transmitted. The steering assist control unit 20 confirms such lane condition information in step S105.

  The steering support control unit 20 determines that the steering support operation is performed in step S106 and executes the steering support control only when an OK (condition satisfaction) result is obtained in all of steps S101 to S105. On the other hand, if it becomes NG (condition not satisfied) in any of steps S101 to S105, it is determined in step S107 that the steering support is stopped, and the steering support control is stopped.

The image processing unit 12 transmits the lane condition information, which is one of the operation conditions, to the steering assist control unit 20 by performing the processes of FIGS. 6, 7, and 8. For example, the image processing unit 12 performs the processing of FIG. 6 as the operation condition determination of the steering assist function at each frame timing at which captured image data is obtained or at each intermittent frame timing.
The image processing unit 12 first performs frame image processing in step S201. This is the above-described forward recognition process using the captured image data of each frame obtained by the left and right imaging units 11L and 11R as described above. Regarding the steering assist function, lane recognition and pedestrian crossing recognition are performed. As for lane recognition, when a break in the lane 90 is recognized, the length of the non-existence distance DL (interval of the broken lane) is also obtained.
Note that the lane 90 may not be recognized at all on the captured image data. First of all, there are cases where the lane 90 does not exist on the road, when the lane 90 is severely worn, or when it is difficult to recognize due to the influence of rain or snow. When the lane 90 is not recognized at all, the following steps S202 to S204 are not substantially performed, and the lane condition NG is satisfied in step S205.

In step S202, the image processing unit 12 performs curvature condition determination. The image processing unit 12 obtains the curvature of the road using detection information from the yaw rate sensor 16 and the vehicle speed sensor 15, for example. Of course, the curvature of the curve of the traveling path (lane) recognized on the captured image may be calculated. When the curvature is obtained, it is determined whether or not the curvature is acceptable for the steering assist function.
In step S203, the image processing unit 12 performs road width condition determination. For example, the road width, that is, the width between the left and right lanes is calculated from the captured image data, and it is determined whether or not it is within the range allowed for the steering assist function.

  In step S204, the image processing unit 12 determines an intersection situation. This is a process for setting the operation / stop as shown in FIG. 4 for the steering assistance in accordance with the intersection situation as shown in FIGS. The details of the processing are shown in FIG. 7. Specifically, the intersection situation determination determines whether or not it is a “support non-execution intersection” where it is desirable not to operate the steering assistance, and the return suppression is performed according to the situation. It becomes processing to perform.

As step S301 in FIG. 7, the image processing unit 12 confirms whether or not it is the timing immediately before the intersection. For example, the image processing unit 12 determines that there is a possibility of an intersection because the lane 90 is interrupted or the pedestrian crossing 95 exists.
When a break in the lane 90 is found, the timing of passing a predetermined distance before the break position (position PC1 in FIG. 2) is set as the timing immediately before the intersection. Alternatively, when the pedestrian crossing 95 is detected, the timing of passing a predetermined distance before the pedestrian crossing may be set as the timing immediately before the intersection.
Only after such a timing immediately before the intersection, the processing after step S302 in FIG. 7 is performed. Therefore, the intersection situation determination process of FIG. 7 is not substantially performed at a time other than the timing just before the intersection even on a road other than the intersection, during the passage of the intersection, after the passage, or even before entering the intersection. .

At the timing immediately before the intersection, the image processing unit 12 confirms the presence or absence of the pedestrian crossing 95 in step S302. Since the detection of the pedestrian crossing 95 is performed in step S201 in FIG. 6, the process branches according to the result.
First, when the pedestrian crossing 95 is recognized, it is checked in step S303 whether the operation of the steering assist function is permitted. For this confirmation, it may be possible to receive information on whether or not it is operating from the steering assist control unit 20, but whether or not the image processing unit 12 has output the lane condition OK in the latest processing of FIG. It is good also as processing to confirm. As described with reference to FIG. 5, the steering assist function is not operated only by the lane condition, but the function instability due to the lane misrecognition due to the intersection situation may be inappropriately performed in the lane condition OK / NG. It is because it is a big cause. That is, “stopping” and “operating” in the pre-entry operation state described in FIGS. 4A and 4B are considered on the assumption that the conditions of steps S101 to S104 in FIG. 5 are satisfied, and the lane condition is OK / NG. This is because it may be considered as operating / stopping according to the above.

If the operation is permitted at the timing immediately before the intersection, in step S304, the image processing unit 12 confirms whether the lane break interval is large, that is, whether the nonexistence distance DL is equal to or greater than a predetermined distance. If the interval is not large (in the case of “small interval” in FIG. 4), the processing of FIG. If the interval is large, the image processing unit 12 determines that the support non-execution intersection is made in step S305, and further starts return suppression in step S306. For example, counting of an internal counter that defines a period for suppressing the return is started.
If the operation is not permitted in step S303, the image processing unit 12 starts returning suppression in step S306.

If the pedestrian crossing 95 is not recognized, the image processing unit 12 proceeds from step S302 to S307, and confirms whether or not the operation of the steering support function is permitted.
If the operation is permitted, the image processing unit 12 confirms in step S309 whether the lane break interval is large, that is, whether the non-existence distance DL is equal to or greater than a predetermined distance. If the interval is not large (in the case of “small interval”), the processing of FIG. If the interval is large, the image processing unit 12 determines that the support non-execution intersection is made in step S305, and further starts return suppression in step S306.
If the operation is not permitted in step S307, the image processing unit 12 confirms in step S308 whether or not the non-existence distance DL is greater than or equal to a predetermined distance. If the interval is not large, the process is left as it is. When the interval is large, the image processing unit 12 starts the return suppression in step S306.

After performing the intersection situation determination as shown in FIG. 7, the image processing unit 12 outputs lane condition information in step S205 of FIG. Details are shown in FIG.
The image processing unit 12 confirms the lane recognition conditions in step S401. If the lane 90 has not been recognized by the image processing in step S201 in FIG. 6, steering assistance is not performed in the first place. Therefore, lane condition information lane condition NG is output to the steering assistance control unit 20 in step S407.
When the lane can be recognized, the image processing unit 12 performs as follows. In steps S402 and S403, the process branches depending on the determination results of steps S202 and S203 in FIG. That is, the judgment result of the curvature condition and the road width condition is referred to.
In step S404, it is checked whether or not the process (support non-execution intersection determination) in step S305 in FIG. 7 has been performed in the intersection situation determination in step S204.
If either the curvature condition or the road width condition is NG, or if it corresponds to a support non-execution intersection, lane condition information lane condition NG is output to the steering assist control unit 20 in step S407.

In step S405, the image processing unit 12 confirms whether the return is being suppressed. Even if the lane recognition condition, the curvature condition, and the road width condition are all OK and do not correspond to the support non-execution intersection, if the return is being suppressed, the lane condition information lane condition NG is controlled in the steering assist control in step S407. To the unit 20.
The image processing unit 12 proceeds from step S405 to S406 only when the lane recognition condition, the curvature condition, and the road width condition are all OK, does not correspond to the support non-execution intersection, and is not being restrained from returning. The lane condition information “OK” is output to the steering assist control unit 20.

Return suppression will be described. For example, if the image processing unit 12 starts the return suppression count in step S306 of FIG. 7, the image processing unit 12 sets the return suppression flag as an internal flag for a period until the count for a predetermined time is completed. During the period in which the return suppression flag is on, it is determined in step S405 in FIG. Therefore, when the return suppression count is started in step S306 in FIG. 7, lane condition information as the lane condition NG is supplied to the steering assist control unit 20 for a certain period of time even if various conditions are satisfied. .
As understood from the processing of FIG. 5, the steering support control unit 20 operates the steering support function only in the case of ACC on, steering support on, vehicle speed condition OK, lateral acceleration condition OK, and lane condition OK. During this time, the lane condition is not satisfied, and the steering assist is stopped in step S107. That is, even if each condition is substantially satisfied, it does not return to the operating state.

The following effects can be obtained by the operation of the above embodiment.
The steering assist control apparatus according to the embodiment includes imaging units 11L and 11R that obtain captured images obtained by capturing the front of the host vehicle, and an image processing unit that determines the operation conditions (lane conditions) of the steering assist function using the captured images. 12 and steering operation control based on the determination results of a plurality of predetermined operating conditions (conditions of steps S101 to S105 in FIG. 5) including at least the operating conditions (lane conditions) determined by the image processing unit 12. And a steering assist control unit 20. Then, the image processing unit 20 detects the pedestrian crossing 95 from the captured image and the detection result of the non-existence distance DL of the lane 10 by the process of FIG. 7 at the timing immediately before the intersection when it is determined that the host vehicle enters the intersection. Is used to determine whether or not the vehicle is a support non-execution intersection that stops the steering support function, and an operation condition (lane condition) that reflects the determination result is determined.
As a result, the operation / stop of the steering support function according to the situation of the intersection (whether or not it is a support non-execution intersection) is realized, and the stability of the operation state in the intersection can be maintained. For example, unnecessary operations caused by erroneous recognition of the lane can be eliminated or reduced.
In addition, since the processing for determining the support non-execution intersection at the timing immediately before the intersection and the return suppression is performed, the operation support / stop of the steering support function does not occur in the intersection, and the occurrence of hunting is avoided.
For the occupant, it is possible to reduce troublesome indications and sounds of switching of operation / stop of the steering assist function.
Furthermore, since the stop and return of the operation are performed immediately before the intersection, it is easy for the driver to understand the switching timing of the operation / stop, and it is easy to obtain a sense of security.

More specifically, according to the processing example of FIG.
When the pedestrian crossing 95 is detected at the timing immediately before the intersection and the steering assist function is in operation, if the non-existence distance DV of the lane 90 is equal to or greater than a predetermined distance, the intersection is determined to be a support non-execution intersection and the steering is performed. Support function return suppression processing is performed (S301 → S302 → S303 → S304 → S305 → S306). If the lane 90 is interrupted and a pedestrian crossing 95 is detected, the location is likely to be an intersection. Therefore, at wide intersections where the non-existence distance of the lane 90 is long, erroneous recognition of the lane 90 can be avoided by stopping the steering assist, and switching of the operating state within the intersection does not occur by suppressing the return. .
When the pedestrian crossing 95 is detected at the timing immediately before the intersection and the steering support function is stopped, the steering support function return suppression process is performed regardless of the non-existence distance DV (large interval / small interval). It performs (S301->S302->S303-> S306). As a result, switching of the operating state within the intersection does not occur.

If the pedestrian crossing 95 is not detected at the timing immediately before the intersection and the steering assist function is in operation, if the non-existence distance DV is equal to or greater than a predetermined distance, the intersection is determined to be a support non-execution intersection and returned. The suppression process is performed (S301 → S302 → S307 → S309 → S305 → S306). Even if a break in the lane 90 is detected, if the pedestrian crossing 95 is not detected, the location may not be an intersection. However, if the lane non-existence distance DV is longer than a predetermined distance, the lane recognition becomes unstable regardless of whether it is an intersection or not. By switching the operation state within the intersection, it can be prevented from occurring for a certain period of time.
Further, when the pedestrian crossing 95 is not detected at the timing immediately before the intersection and the steering assist function is stopped, if the nonexistence distance DV is equal to or greater than the predetermined distance, a return suppression process is performed (S301 → S302). → S307 → S308 → S306). Thereby, it is possible to prevent the switching of the operation state within the intersection from occurring for a certain period of time.
However, if the non-existence distance DV of the lane 90 is less than the predetermined distance, there is a high possibility that the lane 90 is not an intersection, and since the lane ahead can be observed, the possibility that the lane recognition becomes unstable is small. Therefore, the steering assist function can be effectively exhibited by not suppressing the return.

Further, when the pedestrian crossing 95 is detected at the timing immediately before the intersection and the steering assist function is in operation, if the non-existence distance DV is less than the predetermined distance, it is not determined that the intersection is a support non-execution intersection ( (S301 → S302 → S303 → S304 → S205 in FIG. 6). When a break in the lane 10 is detected and an intersection is estimated due to the presence of the pedestrian crossing 95, there is little possibility of erroneous recognition at an intersection where the non-existence distance DV is less than a predetermined distance. Therefore, the steering support function can be effectively exhibited by enabling the steering support as it is during the steering support operation.
Further, if the pedestrian crossing 95 is not detected at the timing immediately before the intersection and the non-existence distance of the lane is less than the predetermined distance, it is not determined as an assistance non-execution intersection regardless of whether it is operating or stopped (S301 → S302 → S307 → S308 (or S309) → S205 in FIG. Even if the lane 90 is interrupted, if there is a possibility that there is no pedestrian crossing 95 and it is not an intersection, there is little possibility of erroneous recognition at an intersection where the non-existence distance DV is less than a predetermined distance. Therefore, the steering support function can be effectively exhibited by enabling the steering support as long as the steering support is in operation and enabling the steering support even when the steering support is stopped.

  Further, the image processing unit 12 performs a process for preventing the operation condition of the steering support function from being satisfied for a certain period of time as the steering support function return suppression process. By setting the fixed time as a time necessary for preventing the vehicle from returning until the vehicle passes the intersection, hunting and unnecessary operation in the intersection can be appropriately avoided.

The present invention is not limited to the configuration and processing of the embodiment, and various modifications can be considered.
For example, regarding the return suppression, the count time until the return suppression is canceled may be a fixed time, but may be varied according to the vehicle speed at that time, for example.
Alternatively, the count time may be variably set according to the non-existence distance DV of the lane 90, or an appropriate time for passing the intersection may be set from the non-existence distance DV and the vehicle speed.
Further, instead of canceling the return suppression by the time count, a method of canceling when it is confirmed that the state where the lane is reliably detected has continued for a certain period of time can be considered.

In the processing described with reference to FIGS. 4 and 7, the processing content is not changed between the case where the lane 90 is interrupted on both sides and the case where the lane 90 is on one side, but it is also conceivable to change the processing content on both sides or one side.
Various hardware configurations for realizing the configuration shown in FIG. 1 are conceivable. For example, the determination process of the support non-execution intersection as shown in FIG. 7 may be performed by a computer other than the microcomputer as the image processing unit 12, and the image processing unit 12 and the steering support control unit 20 are configured by a plurality of microcomputers. Alternatively, the image processing unit 12 and the steering assist control unit 20 may be formed by an integrated microcomputer. As long as there is a functional part that can be evaluated as an imaging unit, an image processing unit, and a steering assist control unit in the claims of the present invention, the present invention can be configured in any manner.

6, 7, and 8, the image processing unit 12 satisfies all of the lane recognition conditions, the curvature conditions, the road width conditions, and the operation conditions (whether or not the support non-execution intersections) according to the intersection conditions, and The lane condition information is output as the lane condition OK if the return is not being suppressed. However, the determination result of each condition and the return suppression flag information are individually output to the steering support control unit 20, and the steering support control unit is output. Processing such that these are used for determining the operating conditions on the 20th side may be used.
In addition, lane recognition conditions, operating conditions based on intersection conditions, and operating conditions other than return suppression information include curvature conditions, road width conditions, operating conditions (ACC on, steering support on), vehicle speed conditions, and lateral acceleration conditions. These conditions are merely examples, and not all of these conditions are necessary. For example, there may be other operating conditions such as a vehicle position condition in which the host vehicle is positioned in the left and right lanes.
Further, the curvature condition, the operation condition, the vehicle speed condition, and the lateral acceleration condition may be determined by the image processing unit 12, the steering assist control unit 20, or may be determined by other parts. It is only necessary that the steering assist control unit 20 finally performs the steering assist control reflecting the determination result.

  DESCRIPTION OF SYMBOLS 10 ... Imaging unit, 11L, 11R ... Imaging part, 12 ... Image processing part, 15 ... Vehicle speed sensor, 16 ... Yaw rate sensor, 17 ... Lateral acceleration sensor, 20 ... Steering control part, 21 ... Motor drive part, 30 ... Steering mechanism

Claims (5)

An imaging unit for obtaining a captured image obtained by imaging the front of the host vehicle;
An image processing unit for determining an operation condition of the steering assist function using the captured image;
A steering support control unit that performs steering support control based on a determination result of one or more predetermined operation conditions including at least the operation condition determined by the image processing unit;
The image processing unit has a steering support function using the detection result of the pedestrian crossing from the captured image and the detection result of the non-existence distance of the lane at the timing immediately before the intersection when it is determined that the own vehicle enters the intersection. A steering assist control device that determines whether or not a support non-execution intersection is to be stopped and determines an operation condition that reflects the determination result. When the pedestrian crossing is detected at the timing immediately before the intersection and the steering assist function is in operation, the image processing unit determines that the support non-execution intersection Perform processing to suppress the return of operation of the steering assist function while determining,
In addition, when a pedestrian crossing is detected at the timing immediately before the intersection and the steering support function is stopped, processing for suppressing the return of the operation of the steering support function is performed regardless of the non-existence distance of the lane. The steering assist control device according to 1. When the pedestrian crossing has not been detected and the steering assist function is operating at the timing immediately before the intersection, and the non-existence distance of the lane is equal to or greater than a predetermined distance, the image processing unit is not supported And a process of suppressing the return of the operation of the steering assist function,
In addition, when no pedestrian crossing is detected at the timing immediately before the intersection and the steering assist function is stopped, if the non-existence distance of the lane is greater than or equal to a predetermined distance, the operation return of the steering assist function is suppressed. The steering assist control device according to claim 1 or 2, wherein the steering assist control device performs processing. When the pedestrian crossing is detected at the timing immediately before the intersection and the steering assist function is in operation, if the non-existence distance of the lane is less than a predetermined distance, the image processing unit Without judging
Further, if a pedestrian crossing is not detected and the non-existence distance of the lane is less than a predetermined distance at the timing immediately before the intersection, it is not determined as a support non-execution intersection. The steering assist control device described. 4. The steering support control device according to claim 2, wherein the image processing unit performs a process of preventing the operation condition of the steering support function from being satisfied for a certain period of time as a process of suppressing the return of the operation of the steering support function. 5. .

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