JP6627021B2 - Lane change steering control system - Google Patents

Description

  The present invention relates to a lane change steering control system.

  2. Description of the Related Art Conventionally, a lane change steering control system that performs steering control for changing a vehicle traveling in a lane to an adjacent lane has been known. As a technique adopted in such a lane change steering control system, for example, Patent Document 1 discloses a detection device that detects a position of a lane marking of an adjacent lane based on an image captured by a camera.

JP 2013-148948 A

  In the above-described lane change steering control system, since the position of the lane marking of the adjacent lane is detected based on the image taken by the camera, for example, when the vehicle travels at night, when the vehicle travels through a tunnel, or on the road surface If the vehicle is wet, it may be difficult to detect the position of the lane marking of the adjacent lane. Therefore, there is a possibility that the steering control for changing the lane to the adjacent lane cannot be reliably performed.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a lane change steering control system capable of reliably performing steering control for changing a vehicle to an adjacent lane.

  A lane change steering control system according to the present invention is a lane change steering control system that performs a steering control for changing a lane traveling in the own lane to an adjacent lane adjacent to the own lane, and at least around an adjacent lane around the vehicle. A laser sensor that emits laser light on the road surface including the reflected light of the emitted laser light, and detects a position of a lane marking in the adjacent lane opposite to the own lane based on a detection result of the laser sensor. A detection unit; and a control unit that performs steering control based on the position of the lane marking detected by the detection unit.

  In this lane change steering control system, the position of a lane marking on the opposite side in an adjacent lane (hereinafter, also simply referred to as “lane lane marking”) is detected based on the detection result of the laser sensor, and the lane marking of the adjacent lane is detected. Steering control is performed based on the position. Thus, for example, even when the vehicle travels at night, when the vehicle travels in a tunnel, and when the road surface is wet, the position of the lane marking of the adjacent lane can be reliably detected. As a result, it is possible to reliably perform the steering control for changing the vehicle to the adjacent lane.

  In the lane change steering control system according to the present invention, the laser sensor detects information on the position and the received light intensity at a plurality of measurement points on the road surface, and the detecting unit detects the received light intensity of the plurality of measurement points regarding the position in the lane width direction. In the distribution, when there is a peak having a width corresponding to the width of the lane marking, at least a part of the measurement points of the peak is extracted as candidate points, and the position of the lane marking is determined based on the position of the extracted candidate point. May be detected. According to this configuration, even if, for example, another object having a high light receiving intensity exists on the road surface, it is possible to prevent the other object from being erroneously detected as a lane marking of an adjacent lane. As a result, it is possible to more reliably detect the position of the lane marking of the adjacent lane.

  The lane change steering control system according to the present invention further includes a storage unit that stores the position of the lane marking detected by the detection unit, wherein the storage unit detects the position of the lane marking detected by the detection unit when the vehicle travels in a traveling section behind the traveling direction. The detected lane marking position is stored as a lane marking already detected position, and the detecting unit detects the lane marking position based on the lane marking detected position and the candidate point position stored in the storage unit. You may. According to this configuration, it is possible to more reliably detect the position of the lane marking of the adjacent lane by using the detected position of the lane marking stored in the storage unit.

  In the lane change steering control system according to the present invention, the detection unit sets one of the plurality of measurement points as a reference point, and one of the plurality of measurement points in the lane width direction with respect to the reference point. A measurement point that is a first distance smaller than half of the width of the lane marking is set as a first point of interest, and among a plurality of measurement points, the other side in the lane width direction with respect to a reference point is set. A measurement point separated by a second distance smaller than 1/2 of the width of the lane marking is set as a second point of interest, and a lane marking is located on one side in the lane width direction with respect to the reference point among a plurality of measurement points. A measurement point that is a third distance larger than 1/2 of the width of the lane is set as the third point of interest, and the width of the dividing line is set to the other side of the lane width direction with respect to the reference point among the plurality of measurement points. A fourth measurement point larger than 1/2 of the distance is set as the fourth point of interest, and the light reception intensity of the first point of interest and the light reception intensity of the second point of interest are determined. The absolute value of the difference is smaller than the first threshold, the difference between the received light intensity of the first point of interest and the received light intensity of the third point of interest is larger than the second threshold, and the received light intensity of the second point of interest and the fourth focused When the difference between the received light intensity of the point is larger than the third threshold, or when the absolute value of the difference between the received light intensity of the first target point and the received light intensity of the second target point is smaller than the first threshold, The difference between the received light intensity at the point of interest and the received light intensity at the fourth point of interest is greater than the second threshold, and the difference between the received light intensity at the second point of interest and the received light intensity at the third point of interest is greater than the third threshold. In such a case, the reference point may be extracted as a candidate point. According to this configuration, the reference point can be extracted as a candidate point by setting the reference point and a plurality of points of interest and relatively comparing the light receiving intensities at the points of interest.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the lane change steering control system which can perform the steering control which changes a vehicle to an adjacent lane reliably.

1 is a schematic block diagram illustrating a lane change steering control system according to an embodiment. FIG. 2 is a schematic side view showing a vehicle equipped with the lane change steering control system of FIG. 1. FIG. 3 is a schematic diagram illustrating measurement points detected by a laser sensor. It is the schematic which shows the received light intensity distribution of the some measurement point regarding the position of a lane width direction. FIG. 4 is a diagram illustrating a method for extracting candidate points. 2 is a flowchart illustrating a process of extracting candidate points in the lane change steering control system of FIG. 1. 2 is a flowchart illustrating a process of detecting a lane marking based on a candidate point in the lane change steering control system of FIG. 1. FIG. 4 is a diagram illustrating a locus of movement of a vehicle when changing lanes. It is a figure showing a reference run locus. 2 is a flowchart illustrating a process of changing a vehicle lane from an own lane to an adjacent lane in the lane change steering control system of FIG. 1.

  Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the drawings. The same or corresponding elements are denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 1 is a schematic block diagram illustrating a lane change steering control system according to the embodiment. FIG. 2 is a schematic side view showing a vehicle equipped with the lane change steering control system of FIG. FIG. 3 is a schematic diagram illustrating measurement points detected by the laser sensor. In FIG. 3, the direction DF is the traveling direction of the vehicle V, and here, is along the lane. The direction DW is a direction orthogonal to the direction DF, and here is the lane width direction. Note that these directions are for convenience of explanation.

  The lane change steering control system 1 is mounted on the vehicle V and performs steering control for changing the lane of the vehicle V running on the own lane 31 to the adjacent lane 33 adjacent to the own lane 31. The lane change steering control system 1 also includes a pair of left and right lane markings 32 that partition the own lane 31 and a lane marking 34 on the opposite side of the adjacent lane 33 from the own lane 31 (a side farther from the own lane 31). Is detected, and the steering control is performed using the detected positions of the division lines 32 and 34. Examples of the vehicle V to be applied include commercial vehicles such as buses and trucks. The vehicle V is not particularly limited, and may be, for example, any of a large vehicle, a medium-sized vehicle, an ordinary passenger car, a small vehicle, and a light vehicle.

  The lane markings 32 and 34 include, for example, a lane outside line, a lane boundary line, and a lane center line. The roadway outside line is a division line installed outside the roadway in a section in which it is necessary to show a line edge outside the roadway. The lane boundary is a lane marking that is set at the lane boundary of a section that needs to indicate the boundary of the lane in the section of the road with four or more lanes. The roadway centerline is a division line installed at the center of the roadway where the width of the roadway needs to indicate the center in a section of 5.5 m or more.

  The division lines 32 and 34 are installed on the road surface 30 as solid lines or broken lines, for example. In the example shown in FIG. 3, the division line 32 is a lane boundary line, and is set as a broken line. One of the two division lines 34 is a roadway outside line, and the other is a roadway centerline. These division lines 34 are all set as solid lines. For example, in the case of an expressway in Japan, a lane boundary as a broken line has a width W of 0.15 m, a length L of 8 m, and an interval (length of the gap) D of 12 m. Note that the dimensions of the dividing lines 32 and 34 are defined by a predetermined law. For example, when the dividing lines 32 and 34 are one solid line, the width is defined, and the dividing lines 32 and 34 are defined. Is a broken line, the width in the short direction, and the interval and length in the long direction are defined.

  The lane change steering control system 1 here constitutes a driving support system, and performs driving support of the vehicle V. The lane change steering control system 1, for example, when an abnormality occurs in the driver of the vehicle V, issues a warning to the driver of the vehicle V, guides the vehicle V to the shoulder while changing the lane as needed, and stops the vehicle. .

  As shown in FIG. 1, the lane change steering control system 1 includes a laser sensor 2, a driver abnormality detection unit 3, an ECU (Electronic Control Unit) 10, and a support execution unit 20. The laser sensor 2 is a sensor that detects information on a detection target using laser light. As shown in FIGS. 2 and 3, the laser sensor 2 is attached to a predetermined portion of the vehicle V (for example, at the center of the front grill). The laser sensor 2 is electrically connected to the ECU 10 and outputs detected information to the ECU 10.

  As shown in FIG. 3, the laser sensor 2 emits a laser beam on the road surface 30 including the own lane 31 and the adjacent lane 33 around the vehicle V, and receives a reflected light of the emitted laser beam. Thereby, as shown in FIG. 4, the laser sensor 2 detects information on the positions and the received light intensity R at the plurality of measurement points 41 on the road surface 30. Specifically, the laser sensor 2 detects information on the positions and the received light intensity R at a plurality of measurement points 41 on the road surface 30 arranged along the lane width direction DW a fixed distance ahead of the vehicle V. The information on the position detected by the laser sensor 2 includes information on a position along the lane width direction DW. The information on the position along the lane width direction DW is, for example, coordinate information of a coordinate system having the lane width direction DW as a coordinate axis.

  The driver abnormality detection unit 3 detects an abnormality caused by the health of the driver of the vehicle V. The driver abnormality detection unit 3 includes, for example, an in-vehicle camera, a heart rate measuring device, and the like, and detects a driver abnormality based on the driver's face orientation, heart rate, and the like of the vehicle V. The driver abnormality detection unit 3 is electrically connected to the ECU 10 and outputs information on the detected abnormality of the driver to the ECU 10.

  The ECU 10 is configured by a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, for example. The ECU 10 is electrically connected to the support execution unit 20 and outputs a signal related to control for supporting driving of the vehicle V to the support execution unit 20. The ECU 10 includes a detection unit 11, a storage unit 12, and a control unit 13 as its functional configuration. Part of the functional configuration of the ECU 10 constitutes a lane marking detection unit 5 that detects the positions of the lane markings 32 and 34. That is, the lane marking detection unit 5 includes the above-described laser sensor 2, the detection unit 11, and the storage unit 12.

  The detection unit 11 detects the positions of the division lines 32 and 34 based on information on the positions at the plurality of measurement points 41 detected by the laser sensor 2 and the received light intensity R. The detecting unit 11 measures the peak portion 40 when there is a peak portion 40 having a width corresponding to the width of the division lines 32 and 34 in the received light intensity distribution RD of the plurality of measurement points 41 related to the position in the lane width direction DW. At least a part of the point 41 is extracted as a candidate point, and the positions of the division lines 32 and 34 are detected based on the positions of the candidate points. Details of the candidate points will be described later. The width corresponding to the width of the division lines 32 and 34 is the width of the division lines 32 and 34 to be detected or the noise (error) of the detection with respect to the width of the division lines 32 and 34 to be detected. The width includes a range with such a margin (hereinafter, simply referred to as a “margin range”). The margin range can be set, for example, in consideration of the maximum error of the measuring device.

  Further, the width corresponding to the width of the dividing lines 32 and 34 is set to a width substantially equal to the constant width or a constant width when the dividing lines 32 and 34 having a constant width are to be detected. On the other hand, the width can include a margin range. The width corresponding to the width of the dividing lines 32 and 34 is the smallest width among the widths of the dividing lines 32 and 34 when plural types of dividing lines 32 and 34 having different widths are to be detected. A width included in a range equal to or more than (minimum width) and equal to or less than a maximum width (maximum width), or a width equal to or larger than a width smaller than the minimum width by a margin and larger than a width larger than the maximum width by a margin. be able to.

  As an example, when the width of the division lines 32 and 34 to be detected is 0.15 m, the detection unit 11 sets the width corresponding to the width of the division lines 32 and 34 to 0. Candidate points are extracted from the measurement points 41 of the peak portion 40 having a width in the range of 10 m to 0.20 m. Alternatively, when the widths of the division lines 32 and 34 to be detected are 0.15 m and 0.20 m, the detection unit 11 sets a width corresponding to the width of the division lines 32 and 34 to have, for example, a margin. Then, candidate points are extracted from the measurement points 41 of the peak portion 40 having a width in the range of 0.08 m to 0.30 m in the direction. In addition, the detection unit 11 detects the positions of the division lines 32 and 34 based on the detected positions of the division lines 32 and 34 and the positions of the candidate points stored in the storage unit 12 described later. The detection unit 11 outputs information on the detected positions of the division lines 32 and 34 to the storage unit 12 and the control unit 13.

  The storage unit 12 stores the positions of the division lines 32 and 34 detected by the detection unit 11 as detected positions. The storage unit 12 is configured by a memory including, for example, a ROM and a RAM. The storage unit 12 stores at least the detected positions (hereinafter, simply referred to as “detected positions”) of the division lines 32 and 34 detected by the detection unit 11 when the vehicle V travels in the traveling section behind the traveling direction. I do. The traveling section behind the traveling direction is a section from a point that is a fixed distance behind the current position of the vehicle V to the current position of the vehicle V. The fixed distance may be set in advance in accordance with, for example, the longitudinal lengths and intervals of the dividing lines 32 and 34 when the dividing lines 32 and 34 are broken lines. Specifically, when the division lines 32 and 34 are lane boundaries of a Japanese expressway, the fixed distance is determined according to the length (8 m) of the lane boundary and the interval (length of the gap, 12 m). For example, it is set to 30 m, which is 1.5 times the sum of the length and the interval.

  The control unit 13 controls the support execution unit 20 based on the positions of the division lines 32 and 34 detected by the detection unit 11 and information on the driver abnormality detected by the driver abnormality detection unit 3. The support execution unit 20 includes a steering unit 21, a braking unit 22, and an alarm unit 23. Examples of the steering unit 21, the braking unit 22, and the alarm unit 23 include a steering actuator, a brake actuator, and a speaker for alarm, respectively.

  In the lane change steering control system 1 configured as described above, the positions of the lane markings 32 and 34 are detected by the lane marking detector 5. The detected positions of the division lines 32 and 34 are stored in the storage unit 12 as detected positions. In the lane change steering control system 1, for example, when the driver abnormality detecting unit 3 detects the abnormality of the driver of the vehicle V, the warning unit 23 alerts the driver of the vehicle V and detects the abnormality. Based on the positions of the lane markings 32 and 34, steering control is performed so that the vehicle V changes lanes to the road shoulder side, and braking control is performed by the braking unit 22 to stop.

  Next, a method for detecting the positions of the division lines 32 and 34 will be described in detail with reference to FIGS. In the following, a method for detecting the position of the lane marking 34 of the adjacent lane 33 will be described. However, the position of the lane marking 32 of the own lane 31 is also detected in parallel in the same manner. FIG. 4 is a schematic diagram showing the received light intensity distribution at a plurality of measurement points with respect to the position in the lane width direction DW. FIG. 5 is a diagram illustrating a method of extracting candidate points. The "position" on the horizontal axis in FIG. 4 corresponds to the position in the lane width direction DW in FIG.

  From the viewpoint of visibility and the like, for example, a white or yellow paint mixed with a retroreflective material such as glass beads is used for the dividing line 34. For this reason, it is found that the reception intensity R of the reflected light of the laser light by the laser sensor 2 is higher in the division line 34 than in the surrounding road surface 30 (asphalt, concrete, or the like).

  Thus, in the lane change steering control system 1, the laser sensor 2 scans the scan area LS shown in FIG. 3 to detect information on the positions of the plurality of measurement points 41 arranged along the lane width direction DW and the received light intensity R. I do. In the example of FIG. 4, the received light intensity distribution RD is formed by the received light intensity R of the plurality of measurement points 41 in the scan area LS. In the received light intensity distribution RD, when the division line 34 exists in the scan area LS, a peak portion 40 is formed at a position corresponding to the division line 34. The peak portion 40 has a width in the horizontal axis direction corresponding to the width along the lane width direction DW. The peak portion 40 is formed by arranging a plurality of measurement points 41 having the received light intensity R corresponding to the division line 34. The peak portion 40 here includes three measurement points. In other words, the interval between the measurement points 41 adjacent to each other is smaller than １ ／ of the width of the division line 34. For example, when the width of the division line 34 is 0.15 m, the interval between the measurement points 41 is smaller than 0.05 m. In the received light intensity distribution RD shown in FIG. 4, the received light intensity R is constant (flat) except for the peak portion 40, but actually, the received light R depends on an object existing on the road surface 30, a road surface state, and the like. The intensity R may fluctuate slightly and may have a wavy shape.

  As described above, since the division line 34 has a higher received light intensity R than the surrounding road surface 30, the detection unit 11 relatively compares the received light intensity R at each measurement point 41, The measurement point 41 existing in the peak portion 40 can be extracted as a candidate point without using the threshold of the received light intensity R (threshold provided for the absolute value of the received light intensity R). That is, the detection unit 11 sets a reference point and a point of interest as described below for all of the plurality of measurement points 41 in the scan area LS, and relatively compares the received light intensity R.

  As illustrated in FIG. 5, the detection unit 11 sets one of the plurality of measurement points 41 in the scan area LS as the reference point 50. Then, the detection unit 11 executes the following processing for detecting the position of the division line 34 for the reference point 50. The detection unit 11 sequentially performs the processing on all of the plurality of measurement points 41 in the scan area LS in a predetermined order or in a random order, for example. First, the detection unit 11 sets a plurality of points of interest 51, 52, 53, 54 for the reference point 50. The detecting unit 11 sets a first point of interest 51 and a third point of interest 53 on one side in the lane width direction DW with respect to the reference point 50, and a second point of interest 52 and a fourth point of interest on the other side in the lane width direction DW. A point of interest 54 is set.

  For example, the detection unit 11 sets the points of interest 51 to 54 so as to satisfy the following relationship. That is, the first point of interest 51 is the measurement point 41 that is a first distance smaller than half the width of the division line 34 on one side in the lane width direction DW with respect to the reference point 50. The second point of interest 52 is a measurement point 41 that is a second distance smaller than 幅 of the width of the dividing line 34 on the other side in the lane width direction DW with respect to the reference point 50. The third point of interest 53 is a measurement point 41 that is located on one side in the lane width direction DW with respect to the reference point 50 and that is a third distance larger than half the width of the division line 34. The fourth point of interest 54 is the measurement point 41 that is a fourth distance greater than の of the width of the division line 34 on the other side in the lane width direction DW with respect to the reference point 50. Here, the reference point 50 and the first point of interest 51 are adjacent measurement points 41, the reference point 50 and the second point of interest 52 are adjacent measurement points 41, and the first point of interest 51 and the third point of interest The point 53 is an adjacent measurement point 41, and the second point of interest 52 and the fourth point of interest 54 are adjacent measurement points 41.

  Alternatively, when a plurality of types of lane markings 34 having different widths are to be detected, the first point of interest 51 is located at one side of the lane width direction DW with respect to the reference point 50. This is a measurement point 41 at a first distance slightly smaller than 小 of the small width. The second point of interest 52 is a measurement point 41 that is a second distance slightly smaller than 最小 of the minimum width of the division line 34 to be detected on the other side in the lane width direction DW with respect to the reference point 50. . The third point of interest 53 is a measurement point 41 that is a third distance away from the reference point 50 on one side in the lane width direction DW, which is slightly larger than 最大 of the maximum width of the detection target marking line 34. . The fourth point of interest 54 is a measurement point 41 that is a fourth distance slightly larger than 最大 of the maximum width of the detection target marking line 34 on the other side in the lane width direction DW with respect to the reference point 50. .

  Here, being slightly smaller than １ ／ of the minimum width of the division line 34 means that the minimum width of the division line 34 to be detected is smaller than the minimum width by a margin. Further, slightly larger than 最小 of the minimum width of the division line 34 means that the maximum width of the division line 34 to be detected is larger by a margin. The margin range can be set, for example, in consideration of the maximum error of the measuring device.

  The distance between the first point of interest 51 and the second point of interest 52 (= first distance + second distance) is, for example, when a section line 34 having a certain width is to be detected, The distance between the third point of interest 53 and the fourth point of interest 54 (= the third distance + the fourth distance) is shorter than the width of the division line 34. Alternatively, for example, when a plurality of types of section lines 34 having different widths are to be detected, the distance (= first distance + second distance) between the first point of interest 51 and the second point of interest 52 The distance between the third point of interest 53 and the fourth point of interest 54 (= the third distance + the fourth distance) is shorter than the minimum width of the line 34 and longer than the maximum width of the division line 34.

  The absolute value of the difference between the light receiving intensity R1 of the first point of interest 51 and the light receiving intensity R2 of the second point of interest 52 is smaller than the first threshold dR1, and the light receiving intensity R1 of the first point of interest 51 and the third point of interest 53 are compared. When the difference between the received light intensity R3 and the received light intensity R2 at the second point of interest 52 and the received light intensity R4 at the fourth point of interest 54 is greater than the third threshold dR3, the difference between FIG. It is determined that the first point of interest 51 and the second point of interest 52 exist in the peak part 40 and the third point of interest 53 and the fourth point of interest 54 do not exist in the peak part 40 as in the example shown in FIG. . Therefore, in this case, the detection unit 11 extracts the reference point 50 as the candidate point 42.

  The first threshold dR1, the second threshold dR2, and the third threshold dR3 are thresholds for the difference (relative value) of the received light intensity R. The first threshold value dR1 may be, for example, a value obtained by obtaining a plurality of differences in the received light intensity R between the measurement points 41 in the peak portion 40 and experimentally calculating the maximum value of these differences. In this case, it is preferable that the measurement points 41 for obtaining the difference are included in the same peak portion 40. The second threshold value dR2 is, for example, a value obtained by obtaining a plurality of differences in received light intensity R between the measurement point 41 at one peak portion 40 and the measurement point 41 at a position other than the peak portion 40, and experimentally obtaining the minimum value of these differences. It may be. In this case, it is preferable that the measurement point 41 at a position other than the peak portion 40 is located between the one peak portion 40 and the peak portion 40 adjacent to the one peak portion 40. The third threshold dR3 may be, for example, the same value as the second threshold dR2.

  For example, when a lane marking 34 having a constant width and a width of 0.15 m along the lane width direction DW is to be detected, the first distance and the second distance are set to 0.05 m, and the third distance is set to 0.05 m. The distance and the fourth distance may be set to 0.10 m. In this case, the detection unit 11 extracts the candidate point 42 from the peak portion 40 having a width in the range of 0.10 m to 0.20 m in the horizontal axis direction, and the lane marking having a width of 0.15 m along the lane width direction DW. 34 can be detected. Alternatively, when a plurality of division lines 34 having different widths are to be detected with the division lines 34 having widths of 0.15 m and 0.20 m along the lane width direction DW, the first distance and the second distance are 0.04 m. The third distance and the fourth distance are set to 0.15 m. Accordingly, when there is a peak portion 40 having a width in the range of 0.08 m to 0.30 m in the horizontal axis direction, the detection unit 11 extracts the candidate point 42 from the peak portion 40 and outputs the candidate point 42 in the lane width direction DW. The positions of the division lines 34 having widths of 0.15 m and 0.20 m can be detected.

  In the above example, the first distance and the second distance are equal, but may be different. Similarly, the third distance and the fourth distance are equal, but may be different. In short, the first distance and the second distance may be smaller than の of the width of the dividing line, and the third distance and the fourth distance may be larger than １ ／ of the width of the dividing line. Incidentally, when a plurality of rows of the dividing lines 34 are drawn on the road surface 30, the third distance and the fourth distance are set to be smaller than the interval between these dividing lines 34.

  Next, a procedure for detecting the position of the division line 34 by the detection unit 11 will be specifically described. First, a processing procedure for extracting the candidate point 42 will be described. FIG. 6 is a flowchart showing a process of extracting the candidate points 42 in the lane change steering control system 1 of FIG.

As shown in FIG. 4, first, one of the plurality of measurement points 41 is set as a reference point 50 (S1). In step S1, points of interest 51, 52, 53, and 54 with respect to the reference point 50 are set. After S1, the absolute value of the difference between the received light intensity R1 at the first point of interest 51 and the received light intensity R2 at the second point of interest 52 is determined by the first threshold dR1 based on whether the following equation (1) holds. Is also determined (S2).
| R1-R2 | <dR1 (1)

If it is determined in step S2 that the absolute value of the difference between the received light intensity R1 of the first point of interest 51 and the received light intensity R2 of the second point of interest 52 is smaller than the first threshold dR1, the following equation (2) is used. It is determined whether or not the difference between the received light intensity R1 of the first point of interest 51 and the received light intensity R3 of the third point of interest 53 is larger than the second threshold dR2 (S3). On the other hand, if it is determined in step S2 that the absolute value of the difference between the received light intensity R1 of the first target point 51 and the received light intensity R2 of the second target point 52 is not smaller than the first threshold dR1, the reference point It is determined that 50 is not the candidate point 42, and the process of step S6 described below is performed.
R1-R3> dR2 (2)

If it is determined in step S3 that the difference between the received light intensity R1 of the first target point 51 and the received light intensity R3 of the third target point 53 is larger than the second threshold value dR2, the following expression (3) is satisfied. It is determined whether or not the difference between the received light intensity R2 of the second point of interest 52 and the received light intensity R4 of the fourth point of interest 54 is larger than the third threshold dR3 (S4). On the other hand, when it is determined in step S3 that the difference between the received light intensity R1 of the first target point 51 and the received light intensity R3 of the third target point 53 is not larger than the second threshold value dR2, the reference point 50 is a candidate. It is determined that it is not the point 42, and the process of step S6 described below is performed.
R2-R4> dR3 (3)

  In step S4, when it is determined that the difference between the received light intensity R2 of the second target point 52 and the received light intensity R4 of the fourth target point 54 is larger than the third threshold dR3, the reference point 50 is a candidate point 42. It can be determined that there is. Therefore, the reference point 50 is extracted as the candidate point 42, and the position of the reference point 50 is set as the position of the candidate point 42 (S5). Then, the process of step S6 described below is performed.

  On the other hand, if it is determined in step S4 that the difference between the received light intensity R2 of the second target point 52 and the received light intensity R4 of the fourth target point 54 is not larger than the third threshold value dR3, the reference point 50 is determined as a candidate. It is determined that it is not the point 42, and the process of step S6 described below is performed.

  In step S6, the reference point 50 is set for all the measurement points 41 in the scan area LS of the laser sensor 2, and the processing in steps S2 to S5 is executed (search for the candidate point 42). Is determined. If it is determined in step S6 that the search for the candidate point 42 has been performed for all the measurement points 41, the process is terminated. On the other hand, when it is determined that the search for the candidate point 42 has not been performed for all the measurement points 41, the process proceeds to the step S1, where the reference point 50 is set for another unsearched measurement point 41, and Extraction continues.

  Subsequently, a processing procedure for detecting the position of the division line 34 based on the position of the extracted candidate point 42 will be described. FIG. 7 is a flowchart showing a process of detecting the lane marking 34 based on the candidate points 42 in the lane change steering control system 1 of FIG.

  The lane change steering control system 1 detects the position of the left lane marking 34 and the position of the right lane marking 34 as the positions of the lane markings 34 of the adjacent lane 33, respectively. In the following, a process for detecting the position of one partition line 34 will be described. However, the position of the other partition line 34 is also detected in parallel in the same manner as this process. The position of the dividing line 34 is a position in the lane width direction DW, and is a position in the coordinate system of the laser sensor 2. Since the laser sensor 2 is attached to the vehicle V, the coordinate system of the laser sensor 2 moves in the traveling direction DF of the vehicle V as the vehicle V advances.

  As shown in FIG. 7, first, it is determined whether or not the division line 34 can be estimated by the quadratic curve fitted to the detected position of the division line 34 stored in the storage unit 12 (S8). When the lane marking 34 cannot be estimated by the quadratic curve, for example, after the detection of the lane marking 34 by the lane change steering control system 1, the vehicle V travels less than a certain distance, and the stored data amount Are not sufficient for the data amount for performing the fitting using the quadratic curve.

  If it is determined in step S8 that the division line 34 cannot be estimated from the quadratic curve, it is determined whether or not there is a candidate point 42 near the position of the previously detected division line 34 (S9). Here, as the position of the previously detected lane marking 34, the newest (nearest) detected position of the lane marking 34 stored in the storage unit 12 is used. The vicinity of the position means, for example, within a certain range from the position, and can be empirically or calculated to be within a range of 0.2 m from the lane width direction DW (hereinafter the same). Note that, for the range near the position, various values may be set according to the required accuracy and the like.

  In step S9, when it is determined that there is a candidate point 42 near the position of the previously detected lane marking 34, the candidate point 42 continues to the position of the previously detected lane marking 34, and the position of the candidate point 42 becomes It can be determined that there is a high possibility that the position is the position of the division line 34. Therefore, the process of step S12 described below is performed. On the other hand, in step S9, when it is determined that there is no candidate point 42 near the position of the previously detected lane marking 34, the processing is performed without detecting the position of the candidate point 42 as the position of the lane marking 34. Will be terminated. When the position of the candidate point 42 is not detected as the position of the lane marking 34, the position of the lane marking 34 may be detected using the detection result of the position of the lane marking 32 of the own lane 31.

  On the other hand, if it is determined in step S8 that the division line 34 can be estimated by the quadratic curve, the position (predicted position) of the division line 34 is predicted from the estimated division line 34 (S10). In step S10, for example, a quadratic curve is fitted to the detected position of the division line 34 stored in the storage unit 12 using the least squares method to estimate the division line 34. Then, assuming that the position of the partition line 34 that will be detected this time exists on the partition line 34, the predicted position of the partition line 34 can be obtained. Then, it is determined whether or not there is a candidate point 42 near the predicted position of the lane marking 34 (S11).

  If it is determined in step S11 that there is a candidate point 42 near the predicted position of the division line 34, it can be determined that there is a high possibility that the position of the candidate point 42 is the position of the division line 34. Therefore, the process of step S12 described below is performed. On the other hand, if it is determined in step S11 that there is no candidate point 42 near the predicted position of the division line 34, the processing is terminated without detecting the position of the candidate point 42 as the position of the division line 34. .

  In step S12, since it is determined that the value of the candidate point 42 is likely to be the position of the division line 34 in the above steps S9 and S11, the position of the candidate point 42 is detected as the position of the division line 34. You. In step S12, the detected position of the division line 34 is stored in the storage unit 12 as the detected position of the detected division line 34. After that, the process ends.

  Next, a process of changing the lane of the vehicle V traveling on the own lane 31 to the adjacent lane 33 will be described. FIG. 8 is a diagram showing a moving track of the lane change of the vehicle V. FIG. 9 is a diagram illustrating the reference traveling locus M1.

  In FIG. 8, the horizontal axis is a position in the traveling direction DF, and the vertical axis is a position in the lane width direction DW. Reference numeral P1 indicates a position (movement start position) at the movement start time, and reference numeral P2 indicates a position (movement completion position) at the movement completion time. The position in the lane width direction DW at the movement start position P1 is set at a predetermined position in the own lane 31, and is set at the center of the own lane 31 here. The position in the lane width direction DW at the movement completion position P2 is set at a predetermined position in the adjacent lane 33, and is set at the center of the adjacent lane 33 here. In the present embodiment, the steering control is performed so that the vehicle V travels in the center of the own lane 31 before the lane change (lane keeping). From this state, the target traveling position of the vehicle V is set to the center of the adjacent lane 33. A lane change to be changed is performed.

  In the lane change steering control system 1, a reference travel locus M1 serving as a reference when changing lanes is set in advance. The reference traveling locus M1 is stored in, for example, the ROM of the ECU 10 and is referred to by the control unit 13. As shown in FIG. 9, the reference traveling locus M1 is represented in a coordinate system including a horizontal position axis (first axis) relating to the position of the vehicle V in the lane width direction DW and a time axis (second axis) relating to time. ing. Here, the reference travel locus M1 is represented by a relationship between a distance y from the movement start position of the vehicle V in the lane width direction DW and an elapsed time t after the start of movement. The reference traveling trajectory M1 is defined as a trajectory of the vehicle V when the vehicle is moved by the reference distance W1 in the lane width direction DW over a predetermined reference time T (for example, 10 seconds). As will be described later, the lane change steering control system 1 calculates the actual travel locus M2 (FIG. 8) by deforming the reference travel locus M1 in the lateral position axis direction and / or the time axis direction. The steering control is performed so that the vehicle V moves along the actual traveling locus M2.

ここで、パラメータａ，ｂ，ｃは、ロジスティック曲線の形状を決定する定数である。
上記数１を熟練ドライバによる車線変更を測定したデータに対してフィッティングすることにより、下記数２が得られた。本実施形態では、下記数２を基準走行軌跡Ｍ１とした。

The reference traveling locus M1 is a curve that simulates, for example, a moving locus of a lane change by a skilled driver, and is defined here by a logistic curve. When defined by a logistic curve, the reference traveling locus M1 is represented by Equation 1 below.

Here, the parameters a, b, and c are constants that determine the shape of the logistic curve.
By fitting the above equation (1) to data obtained by measuring lane changes by a skilled driver, the following equation (2) was obtained. In the present embodiment, the following equation 2 is set as the reference traveling locus M1.

  As shown in FIG. 9, the slope of the movement start time and the slope of the movement completion time on the reference traveling locus M1 (logistic curve) are both 0. The inclination of the reference traveling locus M1 is maximum at an intermediate time between the movement start time and the movement completion time. Thereby, the locus when the vehicle V moves along the reference traveling locus M1 becomes smooth, and the excessive lateral acceleration acting on the vehicle V when changing lanes is suppressed.

  FIG. 10 is a flowchart showing a process of changing the lane of the vehicle V from the own lane 31 to the adjacent lane 33 in the lane change steering control system 1 of FIG. When changing the lane of the vehicle V to the adjacent lane 33, first, the control unit 13 calculates an actual moving distance W2 (FIG. 8) when the lane of the vehicle V is changed based on the position of the lane marking 34 (FIG. 8). S14). For example, the actual moving distance W2 is calculated by specifying the center of the adjacent lane 33 based on the position of the lane marking 34 and calculating the distance in the lane width direction DW from the center of the adjacent lane 33 to the center of the own lane 31. Is done.

  Subsequently, the control unit 13 deforms the reference traveling locus M1 in the lateral position axis direction according to the actual moving distance W2, and calculates the actual traveling locus M2 (S15). For example, the actual traveling trajectory M2 is calculated by expanding and contracting the reference traveling trajectory M1 proportionally in the lateral position axis direction according to the ratio of the actual moving distance W2 to the reference distance W1. Thereby, the scale of the reference traveling locus M1 in the lane width direction DW is adjusted, and the actual traveling locus M2 when the vehicle is moved by the actual moving distance W2 in the lane width direction DW is obtained.

  Subsequently, the control unit 13 calculates the maximum lateral acceleration acting on the vehicle V when the vehicle V is moved along the actual traveling locus M2 over the reference time T (S16). The method of calculating the maximum lateral acceleration is not particularly limited, and a known method can be used. When the vehicle V runs on a curved road, the maximum lateral acceleration is calculated in consideration of the lateral acceleration acting on the vehicle V due to the centrifugal force.

  Subsequently, the control unit 13 determines whether or not the maximum lateral acceleration calculated in step S16 is smaller than a predetermined reference lateral acceleration (S17). When it is determined in step S17 that the maximum lateral acceleration is smaller than the reference lateral acceleration, the control unit 13 executes the steering control so that the vehicle V moves along the actual traveling locus M2 (S18). The value of the reference lateral acceleration is stored, for example, in the ROM of the ECU 10 and is referred to by the control unit 13.

  On the other hand, when it is determined in step S17 that the maximum lateral acceleration is equal to or greater than the reference lateral acceleration, the control unit 13 deforms the actual traveling locus M2 in the time axis direction so that the maximum lateral acceleration becomes smaller than the reference lateral acceleration. The process is executed (S19). For example, by extending the actual traveling locus M2 in the time axis direction according to the magnitude of the difference between the maximum lateral acceleration and the reference lateral acceleration, the actual traveling locus M2 is reduced so that the maximum lateral acceleration becomes smaller than the reference lateral acceleration. Deform. Then, steering control is performed so that the vehicle V moves along the deformed actual traveling locus M2 (S18).

  The value of the reference lateral acceleration is set empirically or experimentally, for example, from the viewpoint of safety and riding comfort. For example, a value at which the driver feels uncomfortable when exceeding the value may be set as the reference lateral acceleration, or a value at which the vehicle behavior of the vehicle V becomes unstable when exceeding the value may be set as the reference lateral acceleration. It may be set as acceleration. When the reference lateral acceleration is set in consideration of the vehicle behavior, it is preferable to take into consideration that the vehicle behavior of the vehicle V having a high center of gravity, such as a bus or a truck, is more likely to be unstable. In addition, when the vehicle speed is high, the behavior of the vehicle is likely to be unstable. Therefore, the configuration may be such that the magnitude of the reference lateral acceleration is changed according to the current vehicle speed.

  By the processing in step S18, the vehicle V changes lanes from the own lane 31 to the adjacent lane 33. At this time, when the center of the vehicle V in the lane width direction DW exceeds the division line 32 of the own lane 31 on the adjacent lane 33 side, it is determined that the lane change has been performed. When it is determined that the lane change has been performed, the lane information is updated so that the adjacent lane 33 of the lane change destination becomes the own lane 31.

  As described above, in the lane change steering control system 1, the position of the lane marking 34 of the adjacent lane 33 is detected based on the detection result of the laser sensor 2, and the steering control is performed based on the detected position of the lane marking 34. Thus, for example, even when the vehicle V travels at night, when the vehicle V travels in a tunnel, and when the road surface is wet, the position of the lane marking 34 of the adjacent lane 33 can be reliably detected. Can be. As a result, the steering control for changing the lane of the vehicle V to the adjacent lane 33 can be reliably performed.

  Since the lane marking 34 of the adjacent lane 33 is farther from the vehicle V than the lane marking 32 of the own lane 31, detection of the lane marking 34 is more difficult than detection of the lane marking 32. On the other hand, in the lane change steering control system 1, the position of the lane marking 34 is detected using the laser sensor 2, so that the position of the lane marking 34 can be reliably (robustly) detected.

  In the lane change steering control system 1, when there is a peak portion 40 having a width corresponding to the width of the lane marking 34 in the received light intensity distribution RD, at least a part of the measurement points 41 of the peak portion 40 is candidate by the detection unit 11. The position of the division line 34 is detected based on the position of the extracted candidate point 42 extracted as the point 42. Thus, even if, for example, another object having a high light receiving intensity R exists on the road surface 30, it is possible to suppress the erroneous detection of the other object as the lane marking 34 of the adjacent lane 33. As a result, the position of the lane marking 34 of the adjacent lane 33 can be detected more reliably.

  In the lane change steering control system 1, the position of the lane marking 34 detected by the detection unit 11 when the vehicle V travels in the traveling section behind the traveling direction is stored in the storage unit 12 as the detected position of the lane marking 34. You. The detection unit 11 detects the position of the division line 34 based on the detected position of the division line 34 and the position of the candidate point 42 stored in the storage unit 12. This makes it possible to more reliably detect the position of the lane marking 34 of the adjacent lane 33 using the detected position of the lane marking 34 stored in the storage unit 12. As a result, even if the peak portion 40 cannot be detected in a relatively short time due to some reason, the position of the division line 34 is used for a while using the detected position of the division line 34 stored in the storage unit 12. Can be detected. The case where the peak portion 40 cannot be detected includes, for example, a case where another vehicle traveling in the adjacent lane 33 blocks the laser beam from the laser sensor 2.

  As a method of detecting the position of the division line 34 based on the received light intensity R, for example, a method in which a certain threshold value is provided for the absolute value of the received light intensity R and the width of a portion exceeding the threshold value may be considered. On the other hand, in the lane change steering control system 1, the detection unit 11 detects the reference point 50, the first attention point 51, the second attention point 52, the third attention point 53, and the fourth attention point 54 for the plurality of measurement points 41. Is set, and the absolute value of the difference between the received light intensity R1 of the first target point 51 and the received light intensity R2 of the second target point 52 is smaller than the first threshold value dR1. The difference between the received light intensity R3 of the point of interest 53 and the received light intensity R2 of the second point of interest 52 and the light receiving intensity R4 of the fourth point of interest 54 is larger than the third threshold dR3. In this case, the reference point 50 is extracted as the candidate point 42. Therefore, it is possible to extract the measurement point 41 of the peak portion 40 as the candidate point 42 without using a threshold value for the absolute value of the received light intensity R (in other words, qualitatively, not quantitatively). .

  As shown in FIG. 4, the received light intensity distribution RD includes a peak portion 40 corresponding to the dividing line 32 and a peak portion 40 corresponding to the dividing line 34. It is smaller than the received light intensity R of the line 32. In the lane change steering control system 1, both positions of the lane markings 32 and 34 are detected, and the one of the detected lane markings 32 and 34 that is farther from the vehicle V and has a smaller absolute value of the received light intensity R is defined as the lane marking 34. As a result, the position of the demarcation line 34 can be reliably detected.

  A plurality of types of division lines 34 having different widths may be installed on the road surface 30. In this case, in the lane change steering control system 1, when a plurality of types of lane markings 34 having different widths are to be detected, the detection unit 11 determines that the first distance is one of the minimum width of the lane marking 34 to be detected. / 2, the second distance is slightly smaller than 最小 of the minimum width of the detection target division line 34, and the third distance is the distance of the detection target division line 34. The fourth distance is set to a distance slightly larger than 1/2 of the maximum width of the division line 34 to be detected. As described above, by setting the first distance, the second distance, the third distance, and the fourth distance using the minimum width and the maximum width of the division line 34 to be detected, the minimum width and the maximum width are set. The measurement point 41 of the peak portion 40 corresponding to the width is extracted as the candidate point 42, so that it is possible to accurately detect the positions of a plurality of types of division lines 34 having different widths.

  It should be noted that, for example, when a road sign such as a character indicating a destination or an arrow is written on the road surface 30, or when another object having a high light receiving intensity R other than the lane marking 34 is present on the road surface 30, for example, noise as noise is generated. When the received light intensity R increases, the division line 34 may be erroneously detected. Therefore, in the present embodiment, for example, by utilizing the fact that the lane marking 34 on the highway is continuously extended as a solid line or a dashed line except for a part of a tollgate or the like, the existing lane marking 34 is detected. The position of the division line 34 that will be detected next is predicted from the detected position, and the candidates of the division line 34 are associated (see S9 above). Thereby, it is possible to suppress the erroneous detection of the road marking or the like as the lane marking line 34 and the erroneous detection of another object as the lane marking line 34, and to robustly detect the position of the lane marking 34 viewed from the vehicle V. it can.

  Further, in the lane change steering control system 1, based on the position of the lane marking 34 of the adjacent lane 33, the actual travel distance W2 in which the vehicle V moves in the lane width direction DW when the lane is changed from the own lane 31 to the adjacent lane 33. Is calculated (S14), and the actual travel locus M2 is calculated by deforming the preset reference travel locus M1 in the lateral position axis direction according to the actual travel distance W2 (S15). Then, the steering control is executed so that the vehicle V moves along the calculated actual traveling locus M2 (S18). Thereby, the scale of the reference traveling locus M1 in the lane width direction DW is adjusted according to the actual moving distance W2 that the vehicle V actually moves when changing lanes, and the vehicle V moves along the obtained actual traveling locus M2. It will be. Therefore, it is possible to suppress the execution of the steering control accompanied by the sudden steering, and to realize a smooth lane change. As a result, it is possible to stabilize the vehicle behavior when changing lanes.

  In the lane change steering control system 1, the actual traveling locus M2 is changed in the time axis direction so that the maximum lateral acceleration acting on the vehicle V when the vehicle V moves along the actual traveling locus M2 becomes smaller than the reference lateral acceleration. (S19). Therefore, the acceleration acting on the vehicle V in the lane width direction DW can be made smaller than the reference lateral acceleration, and the vehicle behavior when changing lanes can be further stabilized.

  In the conventional lane change steering control system, when the target travel position is changed from the center of the own lane 31 to the center of the adjacent lane 33 at the time of lane change, the lateral deviation between the target travel position and the current travel position is changed. Is suddenly increased, so that there is a possibility that steering control involving sudden steering may be performed. On the other hand, the lane change steering control system 1 changes the lane of the vehicle V at a lateral acceleration smaller than a predetermined reference lateral acceleration over a time longer than at least the reference time T. Is suppressed, and a smooth lane change (a lane change that can simulate driving by a skilled driver) can be realized.

  In the lane change steering control system 1, the reference traveling locus M1 is defined by a logistic curve. The inclination of the movement start time and the inclination of the movement completion time in the reference traveling trajectory M1 are 0, and the inclination of the reference traveling trajectory M1 is maximum at an intermediate time between the movement start time and the movement completion time. Therefore, a smoother lane change can be realized, and the vehicle behavior at the time of the lane change can be further stabilized.

  The preferred embodiment according to the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the laser sensor 2 is attached to the center of the front grill of the vehicle V. However, the laser sensor 2 has information on the positions and the received light intensity R at a plurality of measurement points 41 on the road surface 30 around the vehicle V. May be attached to a portion other than the center of the front grill of the vehicle V (for example, a side mirror of the vehicle V).

  In the above embodiment, as an example of the driving support based on the detected position of the lane marking 34, the driving support when an abnormality occurs in the driver of the vehicle V (alerts a warning to the driver of the vehicle V and sets the vehicle V as necessary) (The support to stop the vehicle on the roadside while changing lanes), but other driving support may be used.

  In the above embodiment, as shown in FIG. 3, the laser sensor 2 scans the scan area LS along the lane width direction DW at a predetermined distance in front of the vehicle V. On the other hand, the scanning may be performed on the road surface 30.

  In the above embodiment, when the candidate point 42 is extracted, whether the difference between the received light intensities R1 and R3 is larger than the second threshold dR2 and whether the difference between the received light intensities R2 and R4 is larger than the third threshold dR3. Instead, it is determined whether the difference between the received light intensities R1 and R4 is larger than the second threshold dR2 and whether the difference between the received light intensities R2 and R3 is larger than the third threshold dR3. It may be determined.

  In the above embodiment, four points of interest 51, 52, 53, and 54 are set for the reference point 50, but more points of interest may be set. For example, with respect to the reference point 50, a fifth point of interest separated from the reference point 50 by a fifth distance larger than the first distance and smaller than the third distance is set on one side of the lane width direction DW. A sixth point of interest separated by a sixth distance larger than the second distance and smaller than the fourth distance may be set on the other side in the width direction DW. In this case, the difference between the received light intensities R1, R2, R5, and R6 at the points of interest 51, 52, 55, and 56 is calculated, and the difference between the received light intensities R5, R6, R3, and R4 at the points of interest 55, 56, 53, and 54 is calculated. Is calculated, the peak portion 40 having a width in the range of (first distance + second distance) to (fifth distance + sixth distance) in the horizontal axis direction and (fifth distance + second distance) in the horizontal axis direction The peak portion 40 having a width in the range of (sixth distance) to (third distance + fourth distance) can be distinguished. Thus, the width of the peak portion 40 can be measured according to the number of points of interest and the distance between the points of interest.

In the above embodiment, the candidate point 42 may be extracted by the following method. That is, when the following expressions (A) to (D) using the received light intensity R0 of the reference point 50 are satisfied, the reference point 50 may be extracted as the candidate point 42. However, the predetermined value th1 is the minimum value of the difference between the received light intensity recognized as the division line 34 and the received light intensity recognized as other than the division line 34. The predetermined value th2 is a difference between the minimum value and the maximum value of the received light intensity recognized as the division line 34.
| R1-R0 |> th1 (A)
| R4-R0 |> th1 (B)
| R1-R0 | <th2 (C)
| R2-R0 | <th2 (D)

  In the above embodiment, the method of extracting the candidate point 42 may be any method as long as the measurement point 41 of the peak portion 40 having a width corresponding to the width of the division line 34 is extracted as the candidate point 42, and is not limited to the above embodiment. For example, by determining whether or not the received light intensity of each of the measurement points 41 is equal to or greater than a threshold, the measurement points 41 constituting the peak portion may be specified, and the candidate points 42 may be extracted.

  In the above embodiment, the reference point 50 and the first point of interest 51 are adjacent measurement points 41, but one or more measurement points 41 may exist between them. As such a case, for example, there is a case where the interval between the measurement points 41 is smaller than that in the above embodiment. Similarly, one point also exists between the reference point 50 and the second point of interest 52, between the first point of interest 51 and the third point of interest 53, and between the second point of interest 52 and the fourth point of interest 54. Alternatively, a plurality of measurement points 41 may exist.

  In the above embodiment, the laser sensor 2 detects both the lane marking 32 of the own lane 31 and the lane marking 34 of the adjacent lane 33, but the laser sensor 2 may detect only the position of the lane marking 34, For example, the position of the division line 32 may be detected using an in-vehicle camera or the like. In this case, the laser sensor 2 does not necessarily emit the laser light on the road surface 30 including the own lane 31 and the adjacent lane 33 around the vehicle V, and emits the laser light onto the road surface 30 including at least the adjacent lane 33. It may be emitted.

  In the above embodiment, when the detection of the lane marking 34 of the adjacent lane 33 has failed, the position of the lane marking 34 may be estimated based on the detection result of the lane marking 32 of the own lane 31. In this case, even if the detection of the division line 34 has failed, the position of the division line 34 can be detected using the detection position of the division line 32.

DESCRIPTION OF SYMBOLS 1 ... Lane change steering control system 2: Laser sensor, 11 ... Detection part, 12 ... Storage part, 13 ... Control part, 30 ... Road surface, 31 ... Own lane, 33 ... Neighboring lane, 34 ... Partition line, 40 ... Peak Part, 41: Measurement point, 42: Candidate point, 50: Reference point, 51: First attention point, 52: Second attention point, 53: Third attention point, 54: Fourth attention point, V: Vehicle, R ... Received light intensity, RD ... Received light intensity distribution

Claims (2)

A lane change steering control system that performs a steering control to change a vehicle traveling in the own lane to an adjacent lane adjacent to the own lane,
Around the vehicle, a laser sensor that emits laser light onto a road surface including at least the adjacent lane, and receives reflected light of the emitted laser light,
Based on a detection result of the laser sensor, a detection unit that detects a position of a lane marking opposite to the own lane in the adjacent lane,
A control unit that executes the steering control based on the position of the lane marking detected by the detection unit ,
The laser sensor detects information on positions and received light intensity at a plurality of measurement points on the road surface,
The detection unit,
In the received light intensity distribution of the plurality of measurement points with respect to the position in the lane width direction, if there is a peak having a width corresponding to the width of the lane marking, at least a part of the measurement points of the peak is regarded as a candidate point. Extract,
Detecting the position of the lane marking based on the position of the extracted candidate point,
The detection unit,
Setting one of the measurement points as a reference point,
Among the plurality of measurement points, a measurement point that is a first distance smaller than half of the width of the lane marking on one side in the lane width direction with respect to the reference point is set as a first point of interest. ,
Of the plurality of measurement points, a measurement point that is a second distance smaller than half of the width of the lane marking line on the other side in the lane width direction with respect to the reference point is set as a second point of interest. ,
Of the plurality of measurement points, a measurement point that is located on one side in the lane width direction with respect to the reference point and that is a third distance larger than half the width of the lane marking is set as a third point of interest. ,
Among the plurality of measurement points, a measurement point that is a fourth distance larger than half the width of the lane marking line on the other side in the lane width direction with respect to the reference point is set as a fourth point of interest. ,
An absolute value of a difference between the light receiving intensity of the first point of interest and the light receiving intensity of the second point of interest is smaller than a first threshold value, and the light receiving intensity of the first point of interest and the light receiving intensity of the third point of interest are different. If the difference between the received light intensity is greater than a second threshold, and the difference between the received light intensity of the second point of interest and the received light intensity of the fourth point of interest is greater than a third threshold, or
The absolute value of the difference between the received light intensity of the first point of interest and the received light intensity of the second point of interest is smaller than a first threshold, and the received light intensity of the first point of interest and the When the difference between the received light intensity is larger than a second threshold and the difference between the received light intensity of the second point of interest and the received light intensity of the third point of interest is larger than a third threshold, the reference point A lane change steering control system that is extracted as the candidate points . Further comprising a storage unit that stores the position of the lane marking detected by the detection unit,
The storage unit stores a position of the lane marking detected by the detection unit when the vehicle travels in a traveling section behind a traveling direction as a detected position of the lane marking,
The detection part, based on the previously detected position of the stored the partition line and the position of the candidate point in the storage unit, for detecting a position of the lane line, according to claim 1 lane change steering control system according.

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