JP2017047800A - Drive support apparatus of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive support apparatus of a vehicle, which can prevent an unnecessary lane change caused by steering support control, by accurately determining separation of a preceding vehicle from a driver's own vehicle travel lane.SOLUTION: A steering control part 20 estimates curvature κl of a driver's own vehicle travel lane after registering a preceding vehicle from among front vehicles, and releases preceding vehicle registration when a deviation Δκvl between curvature κv of a running path of the preceding vehicle and a curvature κl of the driver's own vehicle travel lane is a set deviation Δκth or above.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a driving support device for a vehicle traveling along a target course set by driving an electric power steering motor.

  2. Description of the Related Art Conventionally, for the purpose of reducing traffic accidents and reducing the burden on drivers, various driving assistance device technologies that perform steering assistance control so as to travel along a set target course have been developed and proposed. In this type of driving support device, the target course that the host vehicle should travel basically recognizes the left and right white lines that define the host vehicle's driving lane by an out-of-vehicle monitoring device using a stereo camera, monocular camera, etc. Then, it is set based on the recognized white lines on the left and right.

  By the way, such steering assist control has been executed mainly for high-speed travel in which the host vehicle travels at a predetermined vehicle speed or higher. However, in recent years, the host vehicle has a predetermined vehicle speed, such as during a traffic jam. It has been studied to extend and execute even during low-speed traveling that travels at less than On the other hand, when driving at such a low speed, it is difficult to sufficiently detect the white line on the road because the field of view of the outside monitoring device is blocked by a preceding vehicle or the like, and it is difficult to set an effective target course. It may become. In addition, when the vehicle is traveling on a snowy road other than when there is a traffic jam, it is also difficult to sufficiently detect the white line on the road and it is difficult to set an effective target course. It may become.

  On the other hand, for example, in Patent Document 1, the detection point information obtained by the inter-vehicle distance sensor is plotted on the traveling lane shape estimated by the front road shape calculation unit, and is positioned on the traveling lane of the host vehicle. A technique is disclosed in which the nearest detection point group is estimated as a detection point corresponding to a preceding vehicle, and a target course is set based on the detection point group corresponding to the preceding vehicle.

JP 2000-20896 A

  However, when the target course of the own vehicle is set based on the travel locus (detection point group) of the preceding vehicle as in the technique disclosed in Patent Document 1 described above, for example, the preceding vehicle is adjacent to the own vehicle traveling lane. When the lane is changed to this lane, there is a possibility that an unintended lane change may be performed by the steering assist control.

  Therefore, in this type of control, it is important to accurately determine the departure of the preceding vehicle from the own vehicle traveling lane even under the situation where the detection of the white line defining the own vehicle traveling lane is insufficient.

  The present invention has been made in view of the above circumstances, and provides a driving support device for a vehicle that can accurately determine the departure of a preceding vehicle from its own driving lane and prevent unnecessary lane changes due to steering assist control. The purpose is to do.

  A driving support apparatus for a vehicle according to an aspect of the present invention includes a front environment recognition means for recognizing a front environment including left and right white lines ahead of the host vehicle and the front vehicle, and the front vehicle that meets a preset condition among the front vehicles. Preceding vehicle registration means for registering the vehicle as a preceding vehicle, target course setting means capable of setting a target course that the host vehicle should travel based on the preceding vehicle, and a steering angle based on the target course independent of driver input. And a steering control means that is freely configurable, a lane curvature estimating means for estimating the curvature of the own vehicle traveling lane, the curvature of the traveling locus of the preceding vehicle, and the curvature of the own vehicle traveling lane And a preceding vehicle registration canceling means for canceling the registration as the preceding vehicle when the deviation is equal to or larger than the set deviation.

  According to the vehicle driving assistance device of the present invention, it is possible to accurately determine the departure of the preceding vehicle from the own vehicle traveling lane and prevent unnecessary lane changes due to the steering assistance control.

Configuration diagram of a driving support device centering on the steering system of a vehicle Explanatory drawing of coordinate conversion when moving the previous representative position to the current representative position Explanatory drawing which shows the estimated position of the white line candidate point accompanying the movement of a vehicle Flow chart showing steering control routine Explanatory drawing which shows an example of the characteristic of the steering torque of an electric power steering motor, and an electric motor basic current value Illustration of lateral position feedback control Flow chart showing the target course setting routine Flowchart showing the preceding vehicle registration subroutine Explanatory drawing which shows an example of the target course set up based on the white line on either side Explanatory drawing which shows an example of the front vehicle recognized as a preceding vehicle Explanatory drawing which shows the other example of the front vehicle recognized as a preceding vehicle Flow chart showing a preceding vehicle registration cancellation subroutine (part 1) Flowchart showing the preceding vehicle registration cancellation subroutine (part 2) Explanatory drawing which shows an example of the preceding vehicle registration cancellation conditions based on the relationship between the target course and the left and right white line centers Explanatory drawing which shows an example of the preceding vehicle registration cancellation conditions based on the relationship with the parallel vehicle

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to an embodiment of the present invention, FIG. 1 is a configuration diagram of a driving support device centering on a steering system of a vehicle, and FIG. 2 is an explanation of coordinate conversion when moving the previous representative position to the current representative position. FIG. 3, FIG. 3 is an explanatory diagram showing estimated positions of white line candidate points as the vehicle moves, FIG. 4 is a flowchart showing a steering control routine, and FIG. 5 is a graph showing characteristics of the steering torque and electric motor basic current value of the electric power steering motor. FIG. 6 is an explanatory diagram showing an example, FIG. 6 is an explanatory diagram of lateral position feedback control, FIG. 7 is a flowchart showing a target course setting routine, FIG. 8 is a flowchart showing a preceding vehicle registration subroutine, and FIG. 9 is set based on the left and right white lines. FIG. 10 is an explanatory diagram showing an example of a forward vehicle recognized as a preceding vehicle, and FIG. 11 is an explanatory diagram showing another example of the forward vehicle recognized as a preceding vehicle. FIG. 12, FIGS. 12 and 13 are flowcharts showing the preceding vehicle registration cancellation subroutine, FIG. 14 is an explanatory diagram showing an example of the preceding vehicle registration cancellation condition based on the relationship between the target course and the left and right white line centers, and FIG. It is explanatory drawing which shows an example of the preceding vehicle registration cancellation conditions based on a relationship.

  In FIG. 1, reference numeral 1 denotes an electric power steering apparatus that performs driving support by making it possible to set the steering angle independently of the driver input. The electric power steering apparatus 1 includes a steering shaft 2 that is rotatably supported by a vehicle body frame (not shown) via a steering column 3. One end of the steering shaft 2 of the electric power steering apparatus 1 extends toward the driver's seat and the other end extends toward the engine room. A steering wheel 4 is fixed to an end portion of the steering shaft 2 on the driver's seat side, and a pinion shaft 5 is connected to an end portion extending to the engine room side.

  A steering gear box 6 extending in the vehicle width direction is disposed in the engine room, and a rack shaft 7 is inserted into and supported by the steering gear box 6 so as to be reciprocally movable. A rack (not shown) formed on the rack shaft 7 is engaged with a pinion formed on the pinion shaft 5 to form a rack and pinion type steering gear mechanism.

  The left and right ends of the rack shaft 7 protrude from the end of the steering gear box 6, and a front knuckle 9 is connected to the end via a tie rod 8. The front knuckle 9 rotatably supports the left and right wheels 10L and 10R as steering wheels and is supported by the body frame so as to be steerable. Accordingly, when the steering wheel 4 is operated and the steering shaft 2 and the pinion shaft 5 are rotated, the rack shaft 7 is moved in the left-right direction by the rotation of the pinion shaft 5, and the front knuckle 9 is moved to the king pin (not shown). ) And the left and right wheels 10L, 10R are steered in the left-right direction.

  Further, an electric power steering motor (electric motor) 12 is connected to the pinion shaft 5 via an assist transmission mechanism 11, and assists and sets the steering torque applied to the steering wheel 4 by the electric motor 12. The steering torque is applied so that the steering angle becomes the target steering angle. The electric motor 12 is driven by the motor drive unit 21 based on the target current Icmd output as a control output value from the steering control unit 20.

  The steering control unit 20 includes a front recognition device 31 as a front environment recognition means for recognizing the front environment including the left and right white lines in front of the host vehicle and the vehicle, a vehicle speed sensor 32 for detecting the vehicle speed V, a steering angle (actual steering angle). A steering angle sensor 33 that detects θp, a steering torque sensor 34 that detects steering torque Td, a navigation device 35, and the like are connected.

  For example, the front recognition device 31 is attached to the front of the ceiling of the vehicle interior at a certain interval, and a pair of cameras 31L and 31R (stereo cameras) that captures a subject outside the vehicle from different left and right viewpoints, and these cameras 31L, And a stereo image processing device 31a that processes a pair of images (stereo image pairs) in the traveling direction of the host vehicle imaged by 31R.

  Processing of image data from the cameras 31L and 31R is performed, for example, as follows in the stereo image processing device 31a.

  That is, the stereo image processing device 31a first obtains distance information from the amount of deviation of the corresponding position for a pair of image pairs in the traveling direction of the host vehicle imaged by the cameras 31L and 31R, and generates a distance image.

  In recognizing the white line data, the stereo image processing device 31a evaluates the luminance change of the pixels in the width direction of the road based on the knowledge that the white line is brighter than the road surface, and the left and right in the image plane. The position of the white line candidate point is specified on the image plane. The position (x, y, z,) of the white line candidate point in the real space is well 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 is, for example, with the road surface directly below the center of the right camera 31R as the origin, the vehicle width direction as the X axis, the vehicle height direction as the Y axis, and the vehicle length direction. Is defined as the Z-axis. Then, the white line 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 (white line approximate line) using a least square method or the like.

  In recognition of side wall and three-dimensional object data, the stereo image processing device 31a compares the data on the distance image with prestored frames (windows) such as three-dimensional side wall data and three-dimensional object data. Then, while 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 automobiles, two-wheeled vehicles, pedestrians, and power poles. In the extraction of the three-dimensional object data, the stereo image processing device 31a calculates a relative speed with respect to the own vehicle from the rate of temporal change of the distance (relative distance) from each own vehicle, and calculates the relative speed and the own vehicle speed V. The speed of each three-dimensional object is calculated by adding.

  Further, the stereo image processing device 31a also detects the presence / absence of a blinker operation for each vehicle (front vehicle) recognized in front of the host vehicle. That is, for example, the stereo image processing device 31a determines whether or not the area of the high luminance area changes in a predetermined cycle in each of the left and right areas of the recognized forward vehicle (whether or not the enlargement and reduction are repeated). By examining, it is examined whether or not the blinker operation is performed in the vehicle ahead. In particular, when the left and right cameras 31L and 31R constituting the stereo camera are color cameras, the stereo image processing device 31a changes the ratio of the luminances of the R, G, and B colors in the left and right areas of the recognized front vehicle. The presence / absence of turn signal operation is also determined.

  The steering control unit 20 sets a target course on which the host vehicle should travel based on input information from the stereo image processing device 31a and the like. This target course can be basically set based on the left and right white lines that divide the vehicle lane. However, if the white line is about to disappear, if the white line is covered with snow, etc., or if the white line is blocked by a vehicle in front, etc. Even when the vehicle cannot be fully recognized, if there is a preceding vehicle (more specifically, a preceding vehicle that can be the target of follow-up traveling) ahead of the host vehicle, the steering control unit 20 It is possible to set a target course based on the travel locus of the car.

  For this reason, the steering control unit 20 of the present embodiment estimates the travel locus of each forward vehicle. In the estimation of the travel locus, the steering control unit 20 converts, for example, the coordinates of the center point of the rear surface of the forward vehicle recognized before the previous frame in the stereo image processing device 31a into the coordinates of the coordinate system of the current frame. I do.

  Here, such coordinate conversion can be performed using, for example, the vehicle speed V and the yaw angle (that is, an angle calculated from the yaw rate (dθ / dt)). That is, for example, as shown in FIG. 2, assuming that the frame rate is Δt, the movement amounts Δx and Δz that the vehicle moves in the X-axis direction and the Z-axis direction in one frame are expressed by the following equations (1) and (2 ).

Δx = V · Δt · sin θ (1)
Δz = V · Δt · cos θ (2)
Therefore, for example, as shown in FIG. 3, the coordinates of the center point of the preceding vehicle detected in the previous frame are (xold, zold), and the coordinates (presumed that the center point of the preceding vehicle has moved in the current frame ( xpre, zpre) is obtained by the following equations (3) and (4). That is, the coordinates (xpre, zpre) are obtained by subtracting the vehicle movement amounts Δx, Δz from the coordinates (xold, zold) and then converting the coordinates to the vehicle fixed coordinate system (X ′, Z ′) in the current frame. Required by doing.

xpre = (xold · Δx) · cos θ− (zold−Δz) · sin θ (3)
zpre = (xold · Δx) · sin θ− (zold−Δz) · cos θ (4)
The steering control unit 20 sequentially performs such calculation for a center point of each preceding vehicle between a plurality of frames, and uses a least-squares method to calculate a point sequence of the center points of each preceding vehicle after calculation. By approximating the curve, the traveling locus of each preceding vehicle is estimated.

  When the traveling trajectory of each front vehicle is estimated, the steering control unit 20 mainly checks whether there is a preceding vehicle that can be a preceding vehicle in front of the own vehicle based on the relationship between the own vehicle and the traveling trajectory. If there is a preceding vehicle to be registered, the preceding vehicle is registered as a preceding vehicle.

  On the other hand, when the preceding vehicle is registered in front of the host vehicle, the steering control unit 20 mainly sets a deviation Δκ between the curvature κv obtained from the traveling locus of the preceding vehicle and the curvature κl of the host vehicle traveling lane. When it is Δκth or more, the preceding vehicle registration is canceled.

  Here, the curvature κl of the own vehicle lane can be calculated based on the left and right white lines recognized by the stereo image processing device 31a or the map information of the own vehicle lane stored in the in-vehicle navigation device 35. It is. In this case, even if the stereo image processing device 31a cannot recognize a white line with a sufficient distance ahead of the host vehicle, the steering control unit 20 can calculate the curvature κl of the host vehicle traveling lane based on the white line. The coordinates of the white line candidate points detected before the previous frame are transformed into the coordinate system of the current frame by the same calculation as the above-described estimation of the traveling locus of the preceding vehicle, and the left and right white lines up to the set distance behind the host vehicle It is desirable to estimate (re-recognize).

  When the target course is set based on the left and right white lines or the travel locus of the preceding vehicle, the steering control unit 20 performs steering control for causing the host vehicle to travel along the set target course. That is, the steering control unit 20 sets the motor basic current Ipsb in accordance with the steering torque Td of the driver, and calculates the feedforward control amount Iff of the electric motor 12 necessary for traveling along the target course by feedforward control. To do. Further, the steering control unit 20 estimates the vehicle trajectory of the host vehicle, calculates a deviation amount ΔXtv between the vehicle trajectory and the target course at a preset forward gazing point, and performs control so as to eliminate the deviation amount ΔXtv. A lateral position feedback control amount Ifb is calculated. The steering control unit 20 adds these values to calculate the electric motor current value Icmd, and outputs the electric motor current value Icmd to the motor driving unit 21 to drive-control the electric motor 12.

  Thus, in the present embodiment, the steering control unit 20 functions as a travel locus estimation unit, a preceding vehicle registration unit, a target course setting unit, a steering control unit, a lane curvature estimation unit, and a preceding vehicle registration release unit. Is realized.

  Specifically, the steering control unit 20 performs steering control according to, for example, a steering control routine shown in FIG. This routine is repeatedly executed every set time. If the routine is a star, the steering control unit 20 first sets the motor basic current Ipsb in step S101. That is, for example, as shown in FIG. 5, the steering control unit 20 of the present embodiment stores a map for each vehicle speed indicating the relationship between the steering torque Td and the motor basic current Ipsb in advance. The control unit 20 refers to this map and sets the motor basic current Ipsb according to the host vehicle speed V and the steering torque Td.

  In subsequent step S102, the steering control unit 20 checks whether or not a target course for the host vehicle to travel is set. If the target course is set, the process proceeds to step S103, where the target course is set. If not, the process proceeds to step S105.

  When the process proceeds from step S102 to step S103, the steering control unit 20 performs, for example, a feedforward control amount (current) for the electric motor 12 necessary for the host vehicle to travel along the target course by the following equation (5). Value) Iff is calculated.

Iff = Giff · κ (5)
Here, κ represents the curvature of the target course. For example, in the present embodiment in which the target course is approximated by a quadratic curve of x = A · z ² + B · z + C, κ = 2 · A.

  When the process proceeds from step S103 to step S104, the steering control unit 20 uses the following equation (6), for example, to calculate the lateral position feedback control amount (for the electric motor 12) necessary for the host vehicle to travel along the target course. (Current value) Ifb is calculated.

Ifb = Gifb · ΔXtv (6)
Here, Gifb is a gain that is set in advance through experiments and calculations. ΔXtv is calculated by the following equation (7) based on the relationship shown in FIG.

ΔXtv = xt−xv (7)
In this equation (7), xt is the x coordinate of the target course in the z coordinate of the vehicle forward gazing point (0, zv), and xv is the estimated vehicle trajectory in the z coordinate of the vehicle forward gazing point (0, zv). X coordinate. In the present embodiment, zv, which is the forward gaze distance (z coordinate) of the forward gaze point (0, zv), is calculated by zv = T · V. Here, T is a preview time set in advance, and is set to 1.2 sec, for example.

Therefore, xv can be calculated by, for example, the following equation (8) when using vehicle specifications, vehicle-specific stability factor As, or the like based on the running state of the vehicle.
xv = (1/2) · (1 / (1 + As · V ² )) · (θp / Lw) · (T · V) ²
(8)
Here, Lw is a wheel base.

  On the other hand, when the process proceeds from step S102 to step S105, the steering control unit 20 sets the feedforward control amount Iff for the electric motor 12 to “0”, and in the subsequent step S106, the lateral position feedback control amount Ifb for the electric motor 12 is set. After setting to “0”, the process proceeds to step S107.

  When the process proceeds from step S104 or step S106 to step S107, the steering control unit 20 calculates the electric power steering motor current value Icom by, for example, the following equation (9), and the calculated electric power steering motor current value Icom is calculated by the motor. After outputting to the drive unit 21 and controlling the drive of the electric motor 12, the routine is exited.

Icom = Ipsb + Iff + Ifb (9)
Here, for example, when the target course is set based on the trajectory of the preceding vehicle, and when it is determined by the stereo image processing device 31a that the blinker operation is performed on the preceding vehicle. The steering control unit 20 can limit the amount of change in the steering angle. Such limitation of the change amount of the steering angle can be realized by changing a rate limiter or a threshold value of a filter that acts on the electric power steering motor current value Icom, for example.

  In other words, when the turn signal operation place is in the preceding vehicle, the preceding vehicle is likely to leave the own vehicle lane, but until the registration as the preceding vehicle is canceled, the own vehicle Since the vehicle is steered using the travel locus as a target course, there is a possibility that unintended steering by the driver may be performed. On the other hand, since the stereo image processing device 31a may misrecognize the sunlight leaking from the roadside tree into the vehicle body as blinking blinker, it immediately cancels the preceding vehicle registration when detecting blinking blinker in the preceding vehicle This is not preferable from the viewpoint of securing opportunities for steering control as much as possible.

  Therefore, when a turn signal operation is detected in the preceding vehicle, the steering control unit 20 limits the electric power steering motor current value Icom, for example, and performs steering for following driving within a range that does not give the driver a sense of incongruity. In preparation for the departure of the preceding vehicle from the vehicle lane. In this case, the more the blinker blinks, the higher the possibility that the preceding vehicle will leave the driving lane due to a lane change or the like. Therefore, the steering control unit 20 increases the rate limiter as the blinker blinks. It is desirable to change the threshold value so that the filter and the filter work strongly.

  Also, for example, when the target course is set based on the travel locus of the preceding vehicle and the left and right white lines are not a sufficient distance for steering control, but can be recognized more than a predetermined distance, The steering control unit 20 can appropriately limit the amount of change in the steering angle according to the type of white line.

  That is, if the preceding vehicle is approaching any white line with a predetermined distance or more away from the center of the left and right white lines in the vehicle width direction, the preceding vehicle is likely to leave the host vehicle lane. Until the vehicle registration is canceled, the host vehicle is steered using the travel locus of the preceding vehicle as a target course, and thus there is a possibility that the driver does not intend to steer. On the other hand, in a situation where it is uncertain whether or not the preceding vehicle will change lanes, it is possible to cancel the preceding vehicle registration immediately because the preceding vehicle has approached the white line. It is not preferable from the viewpoint of securing the opportunity.

  Therefore, when the preceding vehicle approaches the white line, the steering control unit 20 limits the electric power steering motor current value Icom in accordance with the type of the white line, so that the driver does not make the driver feel uncomfortable. To prepare for the departure of the preceding vehicle from the vehicle lane. That is, for example, when the preceding vehicle is approaching the white line constituted by the broken line, the possibility of changing the lane of the preceding vehicle is higher than when the preceding vehicle is approaching the white line constituted by the solid line. On the other hand, for example, when the preceding vehicle is approaching the white line constituted by the solid line, the possibility of changing the lane is low, and the possibility of steering for the purpose of avoiding some danger is high. Therefore, the steering control unit 20 changes the threshold value and the like so that the rate limiter and the filter work more strongly when the preceding vehicle is approaching the white line made of a broken line than when the preceding vehicle is approaching the white line made of a solid line. It is desirable to do.

  Next, setting of a target course used in the steering control unit 20 in the above-described steering control will be described. The setting of the target course is repeatedly executed at a set time according to the flowchart of the target course setting routine shown in FIG. 7, for example. When the routine is started, the steering control unit 20 first performs each step in step S201. Estimate the running trajectory of the vehicle ahead. That is, the steering control unit 20 converts, for example, the coordinates of the center point of each preceding vehicle recognized in a plurality of frames before the current frame into the coordinate system of the current frame using the above-described equations (1) to (4). An arithmetic operation is performed, and the trajectory of each front vehicle is estimated by approximating the point sequence of the center point of each front vehicle after the calculation to a quadratic curve using the least square method.

  When the process proceeds from step S201 to step S202, the steering control unit 20 estimates the left and right white lines behind the host vehicle. That is, when a white line is recognized in front of the host vehicle by the stereo image processing device 31a, white line candidate points recognized in a plurality of frames before the current frame are calculated by the same calculation as the estimation of the traveling locus of the preceding vehicle. The coordinates of the current line are converted to the coordinate system of the current frame, and the point sequence of the white line candidate points after the calculation is approximated to a quadratic curve using the least square method, so that Estimate the left and right white lines in the range.

  In subsequent step S203, the steering control unit 20 checks whether any of the currently recognized forward vehicles is registered as a preceding vehicle.

  If the steering control unit 20 determines in step S203 that the preceding vehicle has been registered, the process proceeds to step S204. If the steering control unit 20 determines that the preceding vehicle has not been registered, the process proceeds to step S205.

  When the process proceeds from step S203 to step S204, the steering control unit 20 performs a preceding vehicle registration process based on input information from the stereo image processing device 31a and the like. This preceding vehicle registration process is executed, for example, according to the flowchart of the preceding vehicle registration subroutine shown in FIG. 8. When the subroutine starts, the steering control unit 20 first moves forward in front of the host vehicle in step S301. Check if a vehicle is detected.

  If the steering control unit 20 determines in step S301 that a forward vehicle is detected, the process proceeds to step S302. If it is determined that no forward vehicle is detected, the steering control unit 20 exits the subroutine.

  When the process proceeds from step S301 to step S302, the steering control unit 20 checks whether or not the host vehicle speed V = 0 detected by the vehicle speed sensor 32, that is, whether or not the host vehicle is stopped.

  When the steering control unit 20 determines in step S302 that the host vehicle is stopped (the host vehicle speed V = 0), the steering control unit 20 proceeds to step S303, and the host vehicle is traveling (the host vehicle speed V). If it is determined that> 0, the process proceeds to step S304.

  When the process proceeds from step S302 to step S303, the steering control unit 20 checks whether or not the inter-vehicle distance D with the preceding vehicle closest to the host vehicle is equal to or less than a set distance Dth (for example, Dth = 1 to 2 m).

  If the steering control unit 20 determines in step S303 that the inter-vehicle distance D with the nearest preceding vehicle is equal to or less than the set distance Dth, the steering control unit 20 proceeds to step S307, where the inter-vehicle distance D with the nearest preceding vehicle is set. If it is determined that the distance is greater than the distance Dth, the process proceeds to step S304.

  When the process proceeds from step S302 or step S303 to step S304, the steering control unit 20 uses the reference point O (for example, the travel locus estimated in step S201 described above among the currently recognized forward vehicles is set in the host vehicle. The vehicle ahead is extracted closest to the origin of the coordinate system set right below the center of the right camera 31R.

  In subsequent step S305, the steering control unit 20 checks whether or not an error ΔE1 (see FIG. 10) in the vehicle width direction of the extracted traveling locus of the preceding vehicle is equal to or less than the setting error ΔE1th with respect to the reference point of the host vehicle. .

  If the steering control unit 20 determines in step S305 that the error ΔE1 in the vehicle width direction of the travel locus is equal to or less than the setting error ΔE1th, the process proceeds to step S306, where the error ΔE1 in the vehicle width direction of the travel locus is set. If it is determined that the error is greater than ΔE1th, the subroutine is exited.

  When the process proceeds from step S305 to step S306, the steering control unit 20 registers the front vehicle currently extracted as a preceding vehicle, and then exits the subroutine. As described above, the steering control unit 20 of the present embodiment basically selects the preceding vehicle based on the relationship between the host vehicle and the traveling locus of each preceding vehicle.

  On the other hand, when the process proceeds from step S303 to step S307, the steering control unit 20 calculates a lap ratio R between the host vehicle and the nearest preceding vehicle. Here, as shown in FIG. 11, when the vehicle width of the host vehicle is a and the projection width of the preceding vehicle with respect to the host vehicle is b, the lap rate R is obtained by the following equation (10), for example.

R = (b / a) · 100 (10)
In subsequent step S308, the steering control unit 20 checks whether or not the lap rate R between the host vehicle and the nearest preceding vehicle is greater than or equal to the set lap rate Rth.

  Then, in step S308, the steering control unit 20 proceeds to step S309 if the lap rate R is equal to or greater than the set lap rate Rth, and proceeds directly from the subroutine if the lap rate R is less than the set lap rate Rth.

  If it progresses to step S309 from step S308, the steering control part 20 will escape from a subroutine, after registering the front vehicle nearest to the own vehicle as a preceding vehicle. As described above, the steering control unit 20 according to the present embodiment is in the stopped state of the host vehicle V = 0, and in the traffic jam when the distance D with the nearest preceding vehicle is equal to or less than the set distance Dth. Even in a situation where it is difficult to estimate the travel locus of the vehicle over a sufficient distance, the preceding vehicle can be selected based on the lap rate R.

  In the main routine shown in FIG. 7, when the process proceeds from step S203 to step S205, the steering control unit 20 performs a process for canceling the preceding vehicle registration in accordance with a preset condition. The preceding vehicle registration canceling process is executed, for example, according to the flowchart of the preceding vehicle registration canceling process subroutine shown in FIGS. 12 and 13. When the subroutine starts, the steering control unit 20 first, in step S401, It is checked whether the left and right white lines that divide the vehicle lane are recognized.

  Then, in step S401, the steering control unit 20 checks whether at least one of the left and right white lines that divide the vehicle lane is recognized. In this case, the recognition level of the white line does not need to be a level necessary for setting the target course on which the host vehicle should travel, for example, a distance shorter than the recognition distance required for setting the target course. In addition, it is only necessary that the vehicle traveling lane is recognized to a predetermined distance in front of the vehicle.

  If the steering control unit 20 determines in step S401 that at least one of the left and right white lines is recognized, the process proceeds to step S402. If the left and right white lines are determined not to be recognized, Proceed to step S403.

  When the process proceeds from step S401 to step S402, the steering control unit 20 calculates the curvature κl of the host vehicle travel lane based on the white line that divides the host vehicle travel lane, and then proceeds to step S406. That is, for example, when both the left and right white lines are recognized in advance, the steering control unit 20 determines the center of the vehicle lane (the center of the left and right white lines) based on a quadratic curve that approximates these white lines. A quadratic curve is obtained, and the curvature κl of the vehicle lane is estimated based on the quadratic curve centered on the white line. Alternatively, for example, when only one of the left and right white lines is recognized, the steering control unit 20 obtains a quadratic curve obtained by offsetting the quadratic curve approximating the white line to the center of the host vehicle, Based on the offset quadratic curve, the curvature κl of the vehicle lane is estimated.

  On the other hand, when the process proceeds from step S401 to step S403, the steering control unit 20 checks whether or not map information related to the own vehicle travel lane is input from the navigation device 35.

  When the steering control unit 20 determines in step S403 that map information related to the own vehicle travel lane has been input, the steering control unit 20 proceeds to step S404 and determines that map information related to the own vehicle travel lane has not been input. In that case, the process proceeds to step S405.

  When the process proceeds from step S403 to step S404, the steering control unit 20 calculates (estimates) the curvature κl of the host vehicle travel lane based on the map information, and then proceeds to step S406.

  When the process proceeds from step S402 or step S404 to step S406, the steering control unit 20 calculates a deviation | Δκvl | between the curvature κv obtained from the quadratic curve approximating the traveling locus of the preceding vehicle and the curvature κl of the own vehicle traveling lane. Then, it is checked whether or not the deviation | Δκvl | is equal to or larger than the set deviation Δκth. Here, it is assumed that the set deviation Δκth is assumed to turn with a curvature larger than the curvature κl of the vehicle lane when the preceding vehicle changes lanes from the vehicle lane. This is set based on simulation or the like.

  If it is determined in step S406 that the deviation | Δκvl | is equal to or larger than the set deviation Δκth, the steering control unit 20 determines that there is a high possibility that the preceding vehicle will leave the driving lane due to a lane change or the like. The process proceeds to step S412.

  On the other hand, when it is determined in step S406 that the deviation | Δκvl | is less than the set deviation Δκth, the steering control unit 20 proceeds to step S407.

  When the process proceeds from step S403 to step S405, the steering control unit 20 checks whether or not the curvature | κv | obtained from the travel locus of the preceding vehicle is equal to or greater than the set curvature κth. Here, the set curvature κth is set to a curvature larger than the curvature of a tight curve that can be assumed on a road in a general road or a capital expressway.

  When the steering control unit 20 determines in step S405 that the curvature | κv | is equal to or greater than the set curvature κth, the steering control unit 20 may cause the preceding vehicle to leave the own vehicle travel lane due to a lane change or the like. Is determined to be high, the process proceeds to step S412.

  On the other hand, if it is determined in step S405 that the curvature | κv | is less than the set curvature κth, the steering control unit 20 proceeds to step S407.

  When the process proceeds from step S405 or step S406 to step S407, the steering control unit 20 checks whether or not the left and right white lines that define the host vehicle traveling lane are recognized. In this case, the recognition level of the left and right white lines does not need to be a level necessary for setting the target course on which the host vehicle should travel, and is shorter than, for example, the recognition distance required for setting the target course. It is only necessary that the distance is recognized to the extent that the vehicle traveling lane can be determined a predetermined distance in front of the vehicle.

  If the steering control unit 20 determines in step S407 that the left and right white lines are recognized, the process proceeds to step S408, and if it is determined that the left and right white lines are not recognized, the process proceeds to step S409.

  When the process proceeds from step S407 to step S408, the steering control unit 20 determines the deviation | ΔE2 | between the center of the left and right white lines that divide the own vehicle travel lane and the target course set based on the travel locus of the preceding vehicle. 14) is greater than or equal to the set deviation ΔE2th.

  If it is determined in step S408 that the deviation | ΔE2 | between the center of the left and right white lines and the target course is equal to or greater than the set deviation ΔE2th, the steering control unit 20 leaves the own vehicle travel lane due to a lane change or the like. The process proceeds to step S412.

  On the other hand, when it is determined in step S408 that the deviation | ΔE2 | between the center of the left and right white lines and the target course is less than the set deviation ΔE2th, the steering control unit 20 proceeds to step S409.

  When the process proceeds from step S407 or step S408 to step S409, the steering control unit 20 checks whether or not there is a forward vehicle (parallel vehicle) that runs side by side in the adjacent lane of the host vehicle traveling lane. Here, the steering control unit 20 is, for example, the traveling track of the forward vehicle is separated from the center of the host vehicle by a set distance (for example, a general traveling lane width defined by white lines on the left and right) or more in the vehicle width direction. And when the said front vehicle is moving with the same speed component as the advancing direction of the own vehicle, the said front vehicle is judged to be a parallel running vehicle.

  Then, the steering control unit 20 proceeds to step S410 when it is determined in step S409 that there is a parallel running vehicle, and proceeds to step S411 when it is determined that there is no parallel running vehicle.

  When the process proceeds from step S409 to step S410, the steering control unit 20 determines whether or not the preceding vehicle wraps on the side-by-side vehicle, that is, the preceding vehicle enters the region in which the vehicle width is given to the traveling locus of the side-by-side vehicle. Whether or not it exists (see, for example, FIG. 15).

  If it is determined in step S410 that the preceding vehicle is wrapped on the side-by-side vehicle, the steering control unit 20 determines that the preceding vehicle is likely to leave the own vehicle traveling lane due to a lane change or the like. The process proceeds to S412.

  On the other hand, if it is determined in step S410 that the preceding vehicle is not wrapped by the parallel running vehicle, the steering control unit 20 proceeds to step S411.

  When the process proceeds from step S409 or step S410 to step S411, the steering control unit 20 checks whether or not the blinker of the preceding vehicle is blinking more than a set number of times (for example, three times or more).

  In step S411, if it is determined that the blinker of the preceding vehicle is blinking more than the set number of times, the steering control unit 20 determines that there is a high possibility that the preceding vehicle will leave the vehicle lane due to a lane change or the like. Then, the process proceeds to step S412.

  On the other hand, if it is determined in step S411 that the blinker of the preceding vehicle has not flashed more than the set number of times, the steering control unit 20 directly exits the subroutine.

  When the process proceeds from step S405, step S406, step S408, step S410, or step S411 to step S412, the steering control unit 20 cancels the registration of the currently registered preceding vehicle and then exits the subroutine.

  In the main routine of FIG. 7, when the process proceeds from step S204 or step S205 to step S206, the steering control unit 20 determines whether or not the left and right white lines that divide the host vehicle travel lane are recognized more than the set distance, that is, the host vehicle is It is checked whether the left and right white lines of a sufficient distance for setting the target course to be traveled are recognized.

  If it is determined in step S206 that the left and right white lines that divide the host vehicle travel lane have been recognized by the set distance or more, the steering control unit 20 proceeds to step S209 and follows the center of the currently recognized left and right white lines. After setting the target course, exit the routine.

  On the other hand, if it is determined in step S206 that the left and right white lines that divide the vehicle lane are not recognized beyond the set distance, the steering control unit 20 proceeds to step S207, and whether the preceding vehicle is registered in front of the vehicle. Check for no.

  If it is determined in step S207 that a preceding vehicle is registered ahead of the host vehicle, the steering control unit 20 proceeds to step S208, sets the travel locus of the preceding vehicle as a target course, and then exits the routine. .

  On the other hand, if it is determined in step S207 that no preceding vehicle is registered in front of the host vehicle, the steering control unit 20 directly exits the routine.

  According to such an embodiment, an error in the vehicle width direction of the traveling locus with respect to a reference point set in the own vehicle of the preceding vehicle is estimated by recognizing the forward environment including the preceding vehicle and estimating the traveling locus of the preceding vehicle. By registering the preceding vehicle having the smallest | ΔE1 | and the error | ΔE1 | less than or equal to the set threshold value ΔE1th as the preceding vehicle, and setting the target course that the host vehicle should travel based on the locus of the preceding vehicle Thus, stable steering support control can be realized by appropriately setting the target course.

  That is, even if the front vehicle has the closest travel locus to the host vehicle, if the error | ΔE1 | in the vehicle width direction of the travel locus is larger than the setting error ΔE1th, the front vehicle is not registered as a preceding vehicle. It is possible to accurately prevent the target course from being set based on the traveling locus of the preceding vehicle traveling in the adjacent lane, and stable steering support can be realized even when the left and right white lines cannot be sufficiently recognized.

  In this case, when there is a forward vehicle with a lap rate R in the vehicle width direction equal to or greater than the set lap rate Rth within the set distance in front of the host vehicle when the host vehicle is stopped, the preceding vehicle is set as the preceding vehicle. By registering, it is possible to accurately register the preceding vehicle even in a traffic jam where it is difficult to estimate the travel locus of a sufficient distance because the host vehicle and the preceding vehicle hardly move.

  Further, after the preceding vehicle is registered from the preceding vehicle, the curvature κl of the own vehicle traveling lane is estimated, and the deviation Δκvl between the curvature κv of the traveling locus of the preceding vehicle and the curvature κl of the own vehicle traveling lane is set as the set deviation Δκth. When this is the case, by canceling the registration as the preceding vehicle, it is possible to accurately determine the departure of the preceding vehicle from the own vehicle traveling lane and to prevent unnecessary lane changes due to the steering assist control.

  That is, for example, even on an expressway, the assumed curve curvature differs between the general expressway and the Metropolitan Expressway. Although it may be difficult to accurately determine the departure of a vehicle, as in this embodiment, the curvature κl of the vehicle lane is estimated, and the curvature κv of the preceding vehicle and the curvature of the vehicle lane are estimated. By determining the departure of the preceding vehicle (cancellation of the preceding vehicle registration) based on the deviation Δκvl from κl, it is possible to accurately determine the departure of the preceding vehicle for any road shape.

  In this case, if at least one of the left and right white lines that divide the vehicle lane is recognized by the stereo image processing device 31a, the curvature κl of the vehicle lane is estimated based on the white line. Accordingly, it is possible to determine whether to cancel the preceding vehicle registration using real-time information, and to prevent unnecessary lane changes due to the steering assist control.

  In addition, even when the left and right white lines defining the host vehicle lane are not recognized, if there is map information corresponding to the host vehicle lane, the curvature κl of the host vehicle lane is estimated based on the map information. By doing so, even when sufficient white line recognition is not possible, it is possible to widely determine whether to cancel the preceding vehicle registration, and to prevent unnecessary lane changes due to steering assist control.

  Furthermore, even if it is difficult to estimate the curvature κl of the vehicle lane, the preceding vehicle registration is canceled when the curvature κv of the traveling locus of the preceding vehicle is greater than the curvature that can be assumed on the road. Thus, unnecessary lane changes due to steering assist control can be prevented more accurately.

  In addition, this invention is not limited to each embodiment described above, A various deformation | transformation and change are possible, and they are also in the technical scope of this invention.

DESCRIPTION OF SYMBOLS 1 ... Electric power steering apparatus 2 ... Steering shaft 3 ... Steering column 4 ... Steering wheel 5 ... Pinion shaft 6 ... Steering gear box 7 ... Rack shaft 8 ... Tie rod 9 ... Front knuckle 10L, 10R ... Left and right wheel 11 ... Assist transmission mechanism 12 ... Electric motor 20 ... Steering control unit (travel locus estimation means, preceding vehicle registration means, target course setting means, steering control means, lane curvature estimation means, preceding vehicle registration cancellation means)
DESCRIPTION OF SYMBOLS 21 ... Motor drive part 31 ... Forward recognition apparatus 31L, 31R ... Camera 31a ... Stereo image processing apparatus (front environment recognition means)
32 ... Vehicle speed sensor 33 ... Steering angle sensor 34 ... Steering torque sensor 35 ... Navigation device

Claims (4)

Forward environment recognition means for recognizing a forward environment including left and right white lines in front of the host vehicle and the preceding vehicle; preceding vehicle registration means for registering the preceding vehicle that meets a preset condition among the preceding vehicles; Vehicle comprising target course setting means capable of setting a target course on which the host vehicle should travel based on a preceding vehicle, and steering control means capable of setting a steering angle independently of a driver input based on the target course In the driving support device of
Lane curvature estimation means for estimating the curvature of the vehicle lane,
A vehicle comprising: preceding vehicle registration cancellation means for canceling registration as the preceding vehicle when a deviation between a curvature of a traveling locus of the preceding vehicle and a curvature of the own vehicle traveling lane is equal to or larger than a set deviation. Driving assistance device.   The lane curvature estimation means determines the curvature of the own vehicle traveling lane based on the white line when at least one of the left and right white lines defining the own vehicle traveling lane is recognized by the forward environment recognition means. The vehicle driving support device according to claim 1, wherein the driving support device is estimated.   The lane curvature estimation means includes the map information corresponding to the own vehicle traveling lane even when the left and right white lines defining the own vehicle traveling lane are not recognized by the forward environment recognition means. The vehicle driving support device according to claim 2, wherein a curvature of the own vehicle traveling lane is estimated based on the vehicle driving lane.   The preceding vehicle registration canceling means, when the curvature of the traveling lane of the preceding vehicle is not less than a curvature that can be assumed on the road, even when the curvature of the own vehicle traveling lane cannot be estimated by the lane curvature estimating means. The vehicle driving support device according to any one of claims 1 to 3, wherein the registration as the preceding vehicle is canceled.

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