JP4900211B2 - Driving support device, inter-vehicle distance setting method - Google Patents

Description

  The present invention relates to lane keeping support control and inter-vehicle distance control, and more particularly to a travel support apparatus and inter-vehicle distance setting method for avoiding shielding of lane marking lines by a preceding vehicle by inter-vehicle distance control.

  When the preceding vehicle is detected, the preceding vehicle is tracked while maintaining a predetermined distance from the preceding vehicle, and when the preceding vehicle is not detected, the vehicle travels at the set vehicle speed. Distance maintenance support systems are known. In a vehicle equipped with such a driving support device, the driver can keep the distance between the front and rear vehicles by merely operating the steering wheel. Further, there is known a lane keeping support system that recognizes a forward lane marking (hereinafter referred to as a white line) by an imaging device and controls steering torque so as to travel in the lane.

  However, when approaching a preceding vehicle, the photographing device cannot capture a white line due to the presence of the preceding vehicle, and white line recognition becomes difficult (see, for example, Patent Document 1). Here, the target inter-vehicle distance in the inter-vehicle distance maintenance support system is set by replacing the inter-vehicle distance with the preceding vehicle by time (for example, 2 seconds). Therefore, if the setting is the same, the lower the vehicle speed of the host vehicle, the lower the target inter-vehicle distance. The distance becomes shorter.

  For this reason, when both the inter-vehicle distance maintenance support system and the lane maintenance support system are operated, the target inter-vehicle distance is shortened when the vehicle speed of the host vehicle is low. Therefore, the frequency at which the preceding vehicle exists within the white line recognition distance of the imaging device. Will increase. If the preceding vehicle is within the white line recognition distance, the white line recognition rate is lowered, and the application amount of the steering torque is wrong or the alarm timing is shifted.

Therefore, a travel control device has been proposed that processes image information in a narrow processing area when the inter-vehicle distance is small and processes the image information by expanding the processing area as the inter-vehicle distance increases (for example, Patent Document 2). reference.). In addition, a white line recognition device has been proposed in which the distance between the detected preceding vehicle and the detected area is a white line recognition processing area (see, for example, Patent Document 3).
Japanese Patent Laid-Open No. 10-49672 Japanese Patent Laid-Open No. 7-117523 JP-A-9-311999

  However, since the white line can be recognized if the white line is not hidden behind the preceding vehicle even if the inter-vehicle distance is short, the image information processing area is uniform according to the inter-vehicle distance as in the travel control device described in Patent Document 2. If the white line is set, the white line is not recognized even when the white line can be recognized, so the application range of the lane keeping support system is narrowed. Similarly, in the white line recognition apparatus described in Patent Document 3, if the processing area for white line recognition is the inter-vehicle distance regardless of whether the preceding vehicle is blocking the white line, the white line is recognized only in the front processing area. Therefore, even if white line recognition is possible, the white line is not recognized, and the application range of the lane keeping support system is narrowed.

  In view of the above problems, an object of the present invention is to provide a travel support device and an inter-vehicle distance setting method capable of recognizing a white line and providing travel support even when a preceding vehicle is present within the white line recognition distance.

In view of the above problems, the present invention provides an imaging means for photographing the front of a vehicle, a lane marking recognition means for recognizing a lane marking that divides a driving lane from image data captured by the imaging means, and a recognition result of the lane marking. Based on the steering torque generating means for generating a steering torque for maintaining the lane, and vehicle traveling that travels following the preceding vehicle detected in the traveling lane of the host vehicle and travels at a constant vehicle speed when the preceding vehicle is not detected A lane line recognition distance storage means for storing a constant lane line recognition distance, and a temporary target inter-vehicle distance that determines a temporary target inter-vehicle distance according to the speed of the host vehicle during follow-up driving. a target distance determination means, and occlusion detection means for a lane marker of the marking line recognizing means recognizes the lane markings in the recognition distance, the preceding vehicle is detected that the shield, the leading Both having a shielding distance detecting means for detecting a shielding avoidable distance no longer shields the lane marker, and the occlusion detection means is lane marker of the lane marker in the recognition distance is shielded by the preceding vehicle If it is not detected, when the temporary target inter-vehicle distance is determined as the target inter-vehicle distance, and when the shielding detection means detects that the lane marking within the lane marking recognition distance is shielded by the preceding vehicle, And a target inter-vehicle distance determining means for determining the shielding avoidance distance as a target inter-vehicle distance with the lane marking recognition distance as an upper limit .

  According to the present invention, the target inter-vehicle distance is determined as the target inter-vehicle distance only when the preceding vehicle is shielding the white line, so that it is possible to avoid increasing the inter-vehicle distance with the preceding vehicle uniformly and travel The acceptability of the driver of the support device can be improved. In addition, since the preceding vehicle does not exist within the white line recognition distance, it is possible to prevent a decrease in the white line recognition rate, erroneous application of steering torque, and output of an unnecessary alarm.

  Moreover, in one form of this invention, it has the driving environment detection means which detects a driving environment, and the recognition distance setting means which sets a recognition distance variably according to driving environment, It is characterized by the above-mentioned.

  According to the present invention, since the recognition distance becomes variable according to the driving environment, it is possible to further reduce the increase amount and opportunity of the inter-vehicle distance and improve the acceptability of the driver of the driving support device.

  Further, in one aspect of the present invention, the traveling environment detection unit detects the traveling environment from any one of on of the headlight, detection of botsdots, or shutter speed of the imaging unit.

According to the present invention, it is possible to accurately detect the night or daytime, the type of lane marking, and the like, and set the recognition distance suitable for the traveling environment.
Further, in one aspect of the present invention, the shielding detection means is configured so that the preceding vehicle shields the lane marking from the position information of the image area of the preceding vehicle photographed in the image data and the image area of the lane marking. Is detected.

  According to the present invention, the distance to the preceding vehicle is detected by the radar device, and the distance at which the white line is actually shielded in the image data is calculated as compared with the case where the distance is set as the target inter-vehicle distance. It is possible to set the target inter-vehicle distance without any shortage.

  Further, in one aspect of the present invention, the shielding detection means detects the vehicle width of the preceding vehicle, the position of the own vehicle in the width direction, or the travel lane detected by the three-dimensional object detection means that detects the three-dimensional object in front of the own vehicle. Based on one of the widths, it is detected that a preceding vehicle is blocking the lane marking.

  According to the present invention, it is possible to detect that the preceding vehicle is blocking the lane marking with a relatively easy process, so that the system load can be reduced.

  Even if a preceding vehicle exists within the white line recognition distance, it is possible to provide a driving support device and an inter-vehicle distance setting method capable of driving support by recognizing the white line.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram showing an outline of a control procedure of the driving support apparatus 100 of the present embodiment. When maintaining the inter-vehicle distance, the driving support device 100 determines whether or not the preceding vehicle is blocking the white line when the target inter-vehicle distance is within the white line recognition distance. Maintain the distance at the target distance. FIG. 1 shows an outline of control of the driving support device 100. In FIG. 1A, even if the preceding vehicle travels within the white line recognition distance, the target inter-vehicle distance is not increased because the white line is not blocked. In FIG. 1B, since the preceding vehicle is traveling within the white line recognition distance and is blocking the white line, the target inter-vehicle distance is increased. That is, even if the preceding vehicle is traveling within the white line recognition distance, the target inter-vehicle distance is not increased unless the white line recognition is affected, so that it is possible to avoid an increase in the inter-vehicle distance from the preceding vehicle. The driver's acceptability can be improved. Further, since the inter-vehicle distance is increased so as to maintain a white line recognizable state when it is shielded, it is possible to prevent a decrease in the white line recognition rate, an erroneous application of steering torque, and an output of an unnecessary alarm.

  FIG. 2 shows an example of a block diagram of the driving support device 100. The driving support apparatus 100 is configured by connecting an inter-vehicle distance control ECU (Electronic Control Unit) 15 that controls an inter-vehicle distance to various ECUs and an in-vehicle LAN such as a CAN (Controller Area Network). Each ECU such as the inter-vehicle distance control ECU 15 is a computer including a CPU, a RAM, a ROM, and the like.

  The white line recognition and lane keeping support control will be described. The lane keeping assist control is called LKAS (Lane Keeping Assist System) or LDW (Lane Departure Warning), but in the present embodiment, these are not distinguished and are simply referred to as lane keeping assist control.

  An LKA switch 9 and a white line recognition ECU 12 are connected to the inter-vehicle distance control ECU 15, and when the LKA switch 9 is turned on, the vehicle becomes operable. A camera 11 is connected to the white line recognition ECU 12. The camera 11 is mounted on an indoor room mirror, for example, and captures an area that extends horizontally in a predetermined angle range toward the front of the vehicle. The camera 11 outputs image data of a predetermined luminance gradation (for example, 256 gradations) by a photoelectric conversion element such as a complementary metal oxide semiconductor (CMOS) or a charge coupled device (CCD).

  The white line recognition ECU 12 performs image processing on image data that the camera 11 sequentially captures at a predetermined cycle time, and separates left and right lane division lines (hereinafter referred to as white lines) that divide travel lanes drawn on the road being displayed. Is detected.

  FIG. 3 shows an example of image data captured by the camera 11. The straight white line photographed in the image data has a substantially C shape in which the left white line 31 and the right white line 32 intersect the upper side of the vehicle. Part or all of the range captured by the image data in FIG. 3 is the white line recognition distance. When the recognition of the white line is good, the mounting position of the camera 11 is fixed, so if the camera 11 is a single focus, the shooting range, that is, the white line recognition distance is constant, and the length of the white line recognition distance is known to the white line recognition ECU 12. It is. When the camera 11 has a zoom function, the white line recognition distance is known to the white line recognition ECU 12 because there is a fixed relationship between the zoom magnification and the shooting range. In addition, when the white line recognition is not good due to the influence of nighttime, rainy weather, snow, road surface reflections, curves, slopes, etc., the white line recognition distance may be variable depending on the driving environment.

  Since one white line has edges that are high-frequency components at both ends, if the luminance value of the image data ahead of the vehicle is differentiated in the horizontal direction, peaks are obtained at both ends of the white line, and an edge line that connects them in the front-rear direction can be estimated. . Multiple pairs of white line candidate lines are extracted from the estimated multiple edge lines, and white lines are recognized from the thresholds determined by the brightness and the contrast of the road surface, white line width thresholds, etc. One white line is selected.

  Under favorable shooting conditions such as sunny weather, the left white line 31 and the right white line 32 are determined one by one, and by expressing each white line in a model equation, the coordinates of the disappearance points (intersections) of the two left and right white lines can be obtained. It can be calculated. Since the height of the camera 11 from the road surface and the angle formed by the optical axis with respect to the road surface are known, white line information (road curvature, yaw angle Yaw, width W, target travel line O from these and the coordinates of the vanishing point is known. An offset amount D) is calculated.

  The inter-vehicle distance control ECU 15 determines a target steering force (for example, right is positive and left is negative) according to the offset amount D in the opposite direction to the offset so that the offset amount D from the target travel line (for example, the center line) becomes zero. And transmitted to the power steering ECU 16. The power steering ECU 16 is connected to a power steering actuator that rotationally drives the steering shaft, and steers the steering shaft according to the target steering force. Therefore, the lane keeping assist control is realized so that the host vehicle travels in a travel lane where the left white line 31 and the right white line 32 are separated. Note that the inter-vehicle distance control ECU 15 requests the meter ECU 19 to sound the buzzer output device 21 and to display a warning on the information display unit 20 when it determines that the host vehicle may depart from the lane after, for example, a few seconds.

  The inter-vehicle distance control will be described. The inter-vehicle distance control is realized by the inter-vehicle distance control ECU 15 controlling the engine ECU 17, the brake ECU 18 and the meter ECU 19 connected via the in-vehicle LAN. The engine ECU 17 is connected to a stop lamp switch 23 that detects the presence or absence of a brake operation.

  The inter-vehicle distance control is enabled when the main switch of the ACC switch 14 is turned on, and stops operating when the ACC switch 14 is turned off. The ACC switch 14 includes the push-down main switch and a lever-type momentary switch installed on the steering column, for example, and a direction substantially parallel to the turning surface of the steering wheel (hereinafter referred to as the front-rear direction); It is attached so as to be able to swing in a direction substantially perpendicular to the direction (hereinafter referred to as the vertical direction). For example, when the ACC switch 14 is lowered, the vehicle speed at that time is set to the set vehicle speed for constant speed travel. When the ACC switch 14 is lowered the next time, the vehicle speed is reduced and the vehicle speed after deceleration is set to the set vehicle speed (-set). Further, when the ACC switch 14 is raised upward, the vehicle is accelerated from the set vehicle speed, and the vehicle speed after acceleration is set to the set vehicle speed. Then, after the inter-vehicle distance control is once canceled by a CanCel operation or a brake pedal operation described below, when the ACC switch 14 is raised upward at a vehicle speed higher than a predetermined speed, the inter-vehicle distance control is restored (+ reg). Further, when the ACC switch 14 is operated forward, the constant speed traveling and the following traveling are switched (Mode setting), and when operated backward, both the constant speed traveling and the following traveling are canceled (Cancel operation).

  The radar device 13 connected to the inter-vehicle distance control ECU 15 is installed in, for example, a front grill of the vehicle, transmits a millimeter wave toward the front of the vehicle, receives a millimeter wave reflected on the preceding vehicle, and receives the transmitted millimeter wave. The relative speed is detected on the basis of the difference between the frequency of the transmitted wave and the received wave, and the relative distance from the preceding vehicle in the time until it is set. The radar device 13 scans the radar pulse in the left-right direction to detect the direction of the preceding vehicle.

  The inter-vehicle distance control ECU 15 includes a preceding vehicle to be followed in the own lane based on the detection result of the radar device 13, the vehicle speed information detected by the vehicle speed sensor 22, the steering angle (curve radius) of the own vehicle, the yaw rate, and the like. If there is a preceding vehicle, follow-up traveling is performed, and if there is no preceding vehicle, constant-speed traveling is performed to travel at the set vehicle speed.

  4A to 4D are diagrams illustrating an example of constant speed traveling and follow-up traveling. When the preceding vehicle is not detected as shown in FIG. 4A, the inter-vehicle distance control ECU 15 causes the host vehicle to travel at a constant speed at the set vehicle speed. In this case, the inter-vehicle distance control ECU 15 compares the vehicle speed information with the set vehicle speed set by the driver from the ACC switch 14, determines the target acceleration / deceleration, and transmits it to the engine ECU 17. The engine ECU 17 mainly controls the throttle control motor to control the throttle opening and to run at a constant speed at the set vehicle speed.

  When a preceding vehicle is detected as shown in FIG. 4B, the host vehicle travels following the preceding vehicle. The inter-vehicle distance control ECU 15 sets the relative distance detected by the radar device 13, the vehicle speed information, and the set inter-vehicle distance set by the user from about three levels (large distance, medium distance, small distance) with respect to the preceding vehicle to be followed. ), The target inter-vehicle distance from the preceding vehicle is determined. The inter-vehicle distance control ECU 15 determines a target acceleration (when closing the inter-vehicle distance), a deceleration gradient (when widening the inter-vehicle distance), and a brake control request (when the deceleration is large) so that the target inter-vehicle distance is obtained, and the engine ECU 17 And to the brake ECU 18. When the low-speed traveling in FIG. 4 (a) is switched to the following traveling in FIG. 4 (b), the preceding vehicle becomes slower than the own vehicle, so the inter-vehicle distance control ECU 15 decelerates the own vehicle to the same vehicle speed as the preceding vehicle. .

  Thereafter, the vehicle travels following the preceding vehicle as shown in FIG. Since the target inter-vehicle distance is determined in accordance with the arrival time to the preceding vehicle (TTC: Time To Collision) and increases in proportion to the vehicle speed, the target inter-vehicle distance depends on the vehicle speed of the preceding vehicle even if the set inter-vehicle distance is the same. Change. The inter-vehicle distance control ECU 15 calculates the target acceleration, deceleration gradient, and presence / absence of a brake control request while determining the target inter-vehicle distance.

  As shown in FIG. 4D, when the preceding vehicle cannot be supplemented because the lane is changed or the vehicle speed is increased, the set vehicle speed of the own vehicle is faster than the vehicle speed of the preceding vehicle. Accelerate in the process of shifting to driving. Since the inter-vehicle distance control ECU 15 calculates the target acceleration / deceleration and transmits it to the engine ECU 17, the host vehicle gradually accelerates and shifts to the constant speed running shown in FIG.

  When there is a possibility that the preceding vehicle suddenly brakes, for example, when the preceding vehicle suddenly approaches, the inter-vehicle distance control ECU 15 causes the meter ECU 19 to emit a buzzer by the buzzer output device 21 or to turn on a warning lamp by the information display unit 20. Send a warning request to request Hereinafter, the target acceleration, the deceleration gradient, the brake control request, and the warning request are referred to as distance control information.

  When the engine ECU 17 receives the distance control information from the inter-vehicle distance control ECU 15, the engine ECU 17 issues a drive command to the throttle opening of the internal combustion engine (gasoline engine or the like) or to the actuator drive means of the transmission according to the operation state determined from the distance control information. Is output. With these actuators, it becomes possible to control the output of the internal combustion engine, the braking force (engine braking) or the shift shift, and the vehicle speed and the inter-vehicle distance are controlled.

  The brake ECU 18 is connected to a vehicle speed sensor 22 and a brake actuator 24 for duty control of opening / closing of a pressure increase control valve and a pressure reduction control valve provided in the hydraulic circuit. When the brake ECU 18 receives distance control information, particularly a brake control request, from the inter-vehicle distance control ECU 15, the brake ECU 18 controls the brake actuator 24 to brake the vehicle in response to the brake control request. In other words, if sufficient target deceleration cannot be obtained by controlling the throttle opening or shifting down, braking is applied to the vehicle.

  A buzzer output device 21 and an information display unit 20 are connected to the meter ECU 19. The information display unit 20 is composed of a liquid crystal display or the like, and displays on / off of the inter-vehicle distance control, the control status (control mode, set inter-vehicle distance), and the like based on the operation information of the ACC switch 14. When the distance control information, particularly a warning display request, is received from the inter-vehicle distance control ECU 15, the meter ECU 19 displays an approach warning on the information display unit 20 and sounds a warning sound from the buzzer output device 21.

  In this embodiment, a description will be given of the driving support apparatus 100 that determines the target inter-vehicle distance so that the target inter-vehicle distance is equal to or greater than the white line recognition distance.

  FIG. 5 shows an example of the relationship between the vehicle speed and the target inter-vehicle distance, and the vehicle speed and the white line recognition distance. As described above, in the case of following traveling, the target inter-vehicle distance is proportional to the vehicle speed, while the white line recognition distance is constant regardless of the vehicle speed. The driving support apparatus 100 according to the present embodiment determines the target inter-vehicle distance so that the target inter-vehicle distance is equal to or greater than the white line recognition distance. As shown in FIG. 5, the target inter-vehicle distance is smaller than the white line recognition distance up to the vehicle speed A. Therefore, the white line recognition distance is set as the target inter-vehicle distance below the vehicle speed A, and when the vehicle speed A is exceeded, the target inter-vehicle distance is set according to the vehicle speed. Hereinafter, in order to distinguish, the target inter-vehicle distance proportional to the vehicle speed is referred to as a temporary target distance. Thereby, since it is possible to prevent the preceding vehicle from existing in the hatched portion in FIG. 5, it is possible to photograph the white line without being blocked by the preceding vehicle.

  FIG. 6A shows a functional block diagram of the driving support device 100. Such a functional block is realized when at least one CPU of the white line recognition ECU 12 or the inter-vehicle distance control ECU 15 executes a program. The white line recognition distance determining means 41 stores a predetermined white line recognition distance. Although the white line recognition distance is variable, it may be constant in the range where the driving situation does not change, such as daytime or nighttime, and the white line recognition distance corresponding to the driving situation is stored. The white line recognition distance of the white line recognition ECU 12 may be determined based on the white line recognition result. Since the length of the recognized white line becomes clear from the number of pixels of the image data, this length is the white line recognition distance.

  The temporary target distance determining means 42 determines the temporary target inter-vehicle distance by referring to the vehicle speed information of the own vehicle and the set inter-vehicle distance (large distance, medium distance, small distance) set by the user in about three stages. . The white line recognition distance and the provisional target distance have a relationship as shown in FIG. Then, the target inter-vehicle distance determining means 43 determines the larger one of the white line recognition distance and the temporary target distance as the target inter-vehicle distance.

  FIG. 7 is a flowchart showing a procedure in which the driving support device 100 determines the target inter-vehicle distance. The flowchart of FIG. 7 is repeatedly executed when the preceding vehicle is detected and the vehicle speed changes by a predetermined value or every predetermined cycle time.

  First, the temporary target distance determining means 42 determines the temporary target distance of the inter-vehicle distance (S10), and the white line recognition distance determining means 41 determines the current white line recognition distance (S20). Next, the target inter-vehicle distance determining means 43 determines whether or not the temporary target distance is equal to or greater than the white line recognition distance (S30). When the temporary target distance is equal to or greater than the white line recognition distance (Yes in S30), the target inter-vehicle distance determining unit 43 determines the target inter-vehicle distance as the temporary target distance (S40), and when the temporary target distance is not equal to or greater than the white line recognition distance (in S30). No), the target inter-vehicle distance determining means 43 determines the target inter-vehicle distance as the white line recognition distance (S50).

  According to the present embodiment, since no preceding vehicle exists within the white line recognition distance, it is possible to prevent a decrease in white line recognition rate, erroneous application of steering torque, output of an unnecessary alarm, and the like. Hereinafter, the method for determining the target inter-vehicle distance according to the method of this embodiment is referred to as target inter-vehicle distance increase control.

  When the white line recognition distance is fixed, the vehicle speed A is uniquely determined according to the set inter-vehicle distance (large distance, medium distance, small distance). Therefore, the vehicle speed A is determined in advance for each set inter-vehicle distance, When the vehicle speed is equal to or lower than the vehicle speed A, the target inter-vehicle distance may be set as the white line recognition distance.

  In the first embodiment, when the temporary target distance is equal to or less than the white line recognition distance, the target inter-vehicle distance is uniformly set as the white line recognition distance. However, in this case, the inter-vehicle distance with the preceding vehicle tends to increase. However, if the inter-vehicle distance continues to be relatively long, the driver may feel annoyed, for example, the number of interrupted vehicles increases. Therefore, in the present embodiment, the driving support device 100 that sets the target inter-vehicle distance as in the first embodiment only when the lane keeping support control is operable will be described.

FIG. 6B shows a functional block diagram of the driving support device 100 of this embodiment. In FIG. 6B, the same parts as those in FIG. 6A are denoted by the same reference numerals, and the description thereof is omitted. The operation determination unit 44 determines whether or not the lane keeping support control is in an operation state. For example, the following conditions must be satisfied for the lane keeping assist control to operate.
・ The LKA switch 9 is on ・ No abnormality is detected in the white line recognition ECU 12 or the camera 11 ・ The winker operation or strong steering operation (lane change or right / left turn) is not performed ・ The wiper switch is in the specified position The operation determination means 44 determines whether the lane keeping assist control is in an operating state by determining the above conditions.

  FIG. 8 is a flowchart illustrating a procedure in which the driving support device 100 determines the target inter-vehicle distance. The flowchart of FIG. 8 is repeatedly executed every predetermined cycle time.

  The operation determination unit 44 determines whether the white line recognition ECU 12 and the camera 11 are in a normal state (S110), whether the LKA switch 9 for lane keeping support is on (S120), whether the vehicle speed is within a predetermined range (S130), white line It is determined whether or not recognition is possible (S140) and whether or not a driver's predetermined operation is detected (S150). If all the determinations are Yes, the target inter-vehicle distance is determined (S160). The method for determining the target inter-vehicle distance in step S160 is the same as that in the first embodiment. Note that the order of determination in FIG.

  According to this embodiment, only when the lane keeping assist control is actually operating, the larger inter-vehicle distance and white line recognition distance is determined as the target inter-vehicle distance, so the inter-vehicle distance from the preceding vehicle is uniformly set. The increase can be avoided and the acceptability of the driver of the driving support device 100 can be improved.

  In Example 1, when the temporary target distance is equal to or less than the white line recognition distance, the target inter-vehicle distance is uniformly set as the white line recognition distance. However, if the preceding vehicle does not block the white line, the temporary target distance is equal to or less than the white line recognition distance. However, it is not necessary to set the target inter-vehicle distance as the white line recognition distance.

  In this embodiment, when the temporary target distance is within the white line recognition distance, it is determined whether or not the preceding vehicle is blocking the white line. The driving support apparatus 100 that determines the avoidance distance as the target inter-vehicle distance will be described.

  FIG. 9 is a diagram illustrating an example of white line shielding by a preceding vehicle. 9A and 9B, the preceding vehicle is traveling within the white line recognition distance. In FIG. 9A, the preceding vehicle is not blocking the white line, whereas FIG. In b), the white line is blocked. In this embodiment, only when the white line within the white line recognition distance is blocked as shown in FIG. 9B, the distance at which the preceding vehicle does not block the white line is determined as the target inter-vehicle distance.

  FIG. 6C shows a functional block diagram of the driving support device 100 in this embodiment. In FIG. 6C, the same components as those in FIG. 6B are denoted by the same reference numerals, and description thereof is omitted. The shielding detection means 45 detects that the preceding vehicle is shielding the white line. Since the preceding vehicle is traveling at the same speed as the own vehicle, the pixel value change between the image data in the area where the preceding vehicle is imaged in the image data is larger than the area where the road surface and the feature are imaged. Few.

  FIG. 9C is a diagram illustrating detection of the shielding amount. The shielding detection unit 45 determines the preceding vehicle area of the rectangular area based on the relative distance and direction from the preceding vehicle detected by the radar device 13. The coordinate space of the radar device 13 and the coordinate space of the image data are associated with each other by, for example, obtaining a projective transformation matrix that projects all the coordinates of the coordinate system of the radar device 13 onto one plane of the coordinate system of the camera 11. It has been.

  For example, the preceding vehicle area is determined from the preceding vehicle area using pattern matching using an area where the pixel value changes little, the vehicle shape, or the vehicle feature amount (number plate, brake lamp lighting, aspect ratio, etc.) May be. Further, the preceding vehicle area may be detected without using the radar device 13.

  The shielding detection means 45 determines whether or not the preceding vehicle area overlaps the white line area. Since the preceding vehicle rarely blocks all the white lines of the white line recognition distance, the recognized white line is extended within the white line recognition distance, and it is detected whether or not the extended white line overlaps the preceding vehicle. If there is a white line on the left and right and one white line is not recognized and the other white line is recognized, the recognized white line is assumed to be symmetrical with respect to the target travel line, and the assumed white line is It may be determined whether or not the preceding vehicle area is shielded.

  The shielding detection unit 45 calculates a shielding ratio (hereinafter referred to as “shielding degree”), and determines that the shielding is performed when the shielding degree exceeds a predetermined value. The degree of occlusion is, for example, the ratio of the number of image data in which occlusion is detected to the past 50 image data, the degree of occlusion position (distance to B in FIG. 9C) relative to the white line recognition distance, or the Both.

  The shielding distance detection means 46 detects the distance immediately before the white line is shielded (distance to B in FIG. 9C), and detects the distance that the preceding vehicle does not shield the white line (hereinafter referred to as shielding avoidance distance). . Although the shielding avoidance distance is close to the white line recognition distance, the target vehicle distance is determined while feeding back the distance at which the preceding vehicle area does not shield the white line while widening the target inter-vehicle distance. The target inter-vehicle distance can be determined. The inter-vehicle distance when the white line is no longer shielded by the preceding vehicle is the shielding avoidance distance.

  In this way, when the temporary target distance is within the white line recognition distance and the preceding vehicle blocks the white line, the target inter-vehicle distance is set to a distance at which the preceding vehicle does not block the white line.

  FIG. 10 is a flowchart illustrating a procedure in which the driving support device 100 determines the target inter-vehicle distance. The flowchart of FIG. 10 is executed when shielding is detected.

  First, the shielding detection means 45 detects the shielding degree of the white line (S210), and determines whether or not the shielding is based on the shielding degree (S220). When the shielding degree is less than the predetermined value (No in S220), the target inter-vehicle distance determining unit 43 still sets the temporary target distance to the target inter-vehicle distance. When the shielding degree is equal to or greater than the predetermined value (Yes in S220), the shielding distance detection unit 46 detects a shielding avoidance distance that is not shielded by the preceding vehicle (S230). The target inter-vehicle distance determining means 43 determines the shielding avoidance distance as the target inter-vehicle distance.

  Several modifications of the present embodiment will be described with reference to FIG. In FIG. 9C, it is detected whether or not the extension of the white line and the position of the preceding vehicle are overlapped, and it is further determined whether or not it is blocked based on the degree of shielding. The degree of shielding may be detected from the position of the vehicle. It may be considered that the width W and the offset amount D from the target travel line O are detected from the white line information until it is shielded. Therefore, the relative position of the host vehicle with respect to the left and right white lines is known. Thus, since the position of the white line in the image data can be estimated, the shielding detection means 45 determines whether or not the preceding vehicle is shielding the white line by applying the preceding vehicle area in which the preceding vehicle is photographed. (FIG. 11 (a)).

  Moreover, you may utilize the vehicle width of a preceding vehicle. Since the millimeter wave transmitted by the radar device 13 is reflected by the preceding vehicle and received by the radar device 13, vehicle width information is included in the reflected wave. Since the relative position of the own vehicle with respect to the left and right white lines is known, the shielding detection means 45 determines whether or not the white line is shielded based on the vehicle width based on the position of the own vehicle (FIG. 11 ( b)).

  Moreover, you may determine whether the white line is shielded based on the relative position with respect to the white line of the own vehicle. The closer to the left or right in the travel lane (the greater the offset amount D), the more easily the white line in the opposite direction is blocked by the preceding vehicle. Therefore, when the offset amount D is greater than or equal to the predetermined value, the shielding detection unit 45 determines that the shielding degree is greater than or equal to the predetermined value (FIG. 11C).

  Moreover, you may determine whether the white line is shielded based on the width. The shorter the width, the easier the white line is shielded by the preceding vehicle. Therefore, when the width in the white line information is less than or equal to the predetermined value, the shielding detection unit 45 determines that the shielding degree is greater than or equal to the predetermined value (FIG. 11D).

  As shown in FIGS. 11A to 11D, when it is simply detected that the shielding is performed, it is difficult to determine the shielding avoidance distance. In this case, the target inter-vehicle distance is, for example, the white line recognition distance. Therefore, when the presence or absence of shielding is detected, the target inter-vehicle distance can be uniformly set as the white line recognition distance.

  According to the present embodiment, only when the preceding vehicle is blocking the white line, the shielding avoidance distance that can avoid the shielding is determined as the target inter-vehicle distance, so it is avoided to increase the inter-vehicle distance with the preceding vehicle uniformly. In addition, the acceptability of the driver can be improved. Compared to the case where the distance to the preceding vehicle is detected by the radar device 13 and this distance is set as the target inter-vehicle distance, the distance at which the white line is actually shielded in the image data is calculated. The distance can be set.

  In Example 3, the target inter-vehicle distance is increased assuming that the white line is shielded by the preceding vehicle when the degree of shielding of the white line is high. On the other hand, in this embodiment, when it is highly likely that the inter-vehicle distance is predicted to be shorter than the white line recognition distance in the future, the driving support device 100 that sets the target inter-vehicle distance long in advance will be described. To do.

  In other words, the driving support device 100 predicts an event in which the inter-vehicle distance is shortened in advance, predicts the necessary amount of inter-vehicle distance, and keeps the inter-vehicle distance long in advance. For example, at present, the target inter-vehicle distance is larger than the white line recognition distance, but when the preceding vehicle decelerates, the target inter-vehicle distance becomes equal to or less than the white line recognition distance, so the target inter-vehicle distance is set longer before that.

  FIG. 12 shows an example of the relationship between the vehicle speed of the preceding vehicle and the inter-vehicle distance. 12A shows the vehicle speed of the preceding vehicle, FIG. 12B shows the change in the inter-vehicle distance when the method of this embodiment is not applied, and FIG. 12C shows the case where the method of this embodiment is applied. Changes in the inter-vehicle distance are shown respectively.

  The preceding vehicle starts decelerating when entering the curve, decreases the vehicle speed until it passes the curve, and starts acceleration after passing the curve, so the vehicle speed increases and stabilizes soon. Since the host vehicle following the preceding vehicle is similarly decelerated and accelerated, the inter-vehicle distance decreases during deceleration and the inter-vehicle distance increases during acceleration as shown in FIG. However, the target inter-vehicle distance falls within the white line recognition distance depending on the vehicle speed of the preceding vehicle on the curve and its duration.

  Therefore, the driving support apparatus 100 of the present embodiment predicts that the preceding vehicle enters the curve, and increases the inter-vehicle distance in advance before the inter-vehicle distance decreases. Because the distance between the vehicles increases before the vehicle enters the curve, the target distance between the vehicles will be less than the white line recognition distance during the curve even if the following distance decreases as the vehicle speed decreases. It is possible to prevent the preceding vehicle from entering the white line recognition distance.

  Fig.13 (a) shows the functional block diagram of the driving assistance device 100 in a present Example. In FIG. 13A, the description of the same components as those in FIG. The deceleration prediction means 47 predicts that the preceding vehicle decelerates based on the road curvature of the white line information, road map information of the navigation system, road-to-vehicle communication, vehicle-to-vehicle communication with the preceding vehicle, and the like. For example, if the presence of a curve or a left / right turn is predicted, the vehicle is predicted to decelerate. When deceleration of the preceding vehicle is predicted, the target inter-vehicle distance determining unit 43 determines a distance obtained by increasing the temporary target distance as the target inter-vehicle distance. The amount of increase is preferably determined according to how much the preceding vehicle decelerates and how long. The target inter-vehicle distance determining means 43 determines the amount of increase based on, for example, white line information, road curvature and curve length obtained from road-to-vehicle communication or road map information.

  FIG. 14 is a flowchart illustrating a procedure in which the driving support device 100 determines the target inter-vehicle distance. The flowchart of FIG. 14 is repeatedly executed at predetermined cycle times while traveling following the preceding vehicle.

  First, the deceleration prediction means 47 extracts an event that shortens the inter-vehicle distance (S310). The deceleration prediction means 47 extracts a curve or the like within a predetermined distance ahead of the own vehicle amount. Then, the deceleration prediction unit 47 determines whether or not the inter-vehicle distance is equal to or less than the white line recognition distance during the event (S320). Whether or not the distance is equal to or less than the white line recognition distance is determined to be equal to or less than the white line recognition distance, for example, when the sum of the curvature radius of the curve, the curve length, or the current inter-vehicle distance is added or any of the values satisfies a threshold value. Is done.

  When it is not predicted that the inter-vehicle distance will be equal to or less than the white line recognition distance (No in S320), the target inter-vehicle distance determination means 43 travels with the temporary inter-vehicle distance set as the target inter-vehicle distance.

  When it is predicted that the inter-vehicle distance is equal to or less than the white line recognition distance (Yes in S320), the target inter-vehicle distance determination unit 43 calculates the increase amount of the target inter-vehicle distance (S330). The amount of increase is determined, for example, by determining the amount of increase in the target inter-vehicle distance according to the total value obtained by weighting and adding to the curvature radius of the curve, the curve length, and the current inter-vehicle distance, and the target inter-vehicle distance is determined (S340). .

  In step S320, it may be determined that the inter-vehicle distance is equal to or less than the white line recognition distance only when the vehicle speed of the preceding vehicle (the vehicle speed of the host vehicle) is higher than the radius of curvature and the curve length. This is because it can be predicted that the preceding vehicle suddenly decelerates and the distance between the vehicle and the host vehicle suddenly decreases and falls within the white line recognition distance.

  In the present embodiment, the vehicle speed of the preceding vehicle immediately before the host vehicle is predicted and the event in which the inter-vehicle distance is shortened is extracted, but from the vehicle position and vehicle speed of the preceding vehicle of the preceding vehicle (hereinafter referred to as the vehicle first), It may be determined whether or not the inter-vehicle distance is shortened. The vehicle position and vehicle speed of the vehicle are acquired by road-to-vehicle communication or vehicle-to-vehicle communication.

  This is detected when the vehicle first enters the curve or turns left and right, and it is determined whether the inter-vehicle distance is equal to or less than the white line recognition distance from the curvature radius and curve length of the curve and the vehicle speed of the vehicle. Since the vehicle speed of the preceding vehicle is considered to be affected by the vehicle speed of the vehicle ahead, by determining whether the inter-vehicle distance is less than or equal to the white line recognition distance from the vehicle position and vehicle speed of the vehicle that travels ahead further, The target inter-vehicle distance can be increased early.

  Further, the inter-vehicle distance may be increased in advance by predicting that there is an interruption immediately before the host vehicle from the adjacent lane. When another vehicle interrupts, the other vehicle becomes a preceding vehicle, and thus the inter-vehicle distance may be within the white line recognition distance. Since the camera 11 is photographing another vehicle in an adjacent lane, it is predicted that the other vehicle will interrupt from the distance between the other vehicle and the white line, blinker blinking, etc., and the target inter-vehicle distance is increased in advance. Thereby, even if interrupted, it can reduce that the distance between vehicles becomes in the white line recognition distance.

  According to this embodiment, when the future inter-vehicle distance is predicted and the inter-vehicle distance is likely to be reduced to the white line recognition distance or less, the target inter-vehicle distance is set to be long in advance, so the white line is shielded by the preceding vehicle. Can be prevented.

  As described in the first embodiment, the white line recognition distance may vary depending on the driving environment. For example, it is 10 to 50 m during the daytime and 10 to 30 m at night due to the convenience of the Lo beam irradiation range. Further, as an example of switching the white line recognition distance more dynamically, there is a case where the vehicle travels on a road that divides the travel line by a bots dot or a reflector (cat's eye) in other countries. A botsdot is a circular stone having a diameter of about 10 cm and a height of about 1 cm arranged at a predetermined interval on a lane marking or a virtual line where a lane marking should be present. When recognizing botsdots, it is necessary to detect a small point, and therefore, a special logic different from the normal white line detection is prepared.

  The white line recognition ECU 12 that detects the botsdots automatically shifts to the botsdots mode when traveling on the lane demarcated by the botsdots. However, since the camera 11 recognizes a point having a diameter of about 10 cm, the detection is performed at distances greater than 20 m. It has become difficult. For this reason, in the botsdots mode, the image processing amount of 10 to 20 m is increased, and processing beyond 20 m is not performed. On the other hand, when driving on a road that divides a driving lane with a white line, the mode shifts to a white line mode, and the white line recognition distance is about 10 to 50 m.

  The driving support device 100 of this embodiment makes the white line recognition distance variable according to the driving environment such as nighttime, daytime, white line, botsdots, and the like. The functional block diagram is the same as FIG. In the white line recognition distance determining means 41 of this embodiment, the white line recognition ECU 12 detects the headlight on / off, the bots dot mode / white line recognition mode, and determines the white line recognition distance. That is, the target inter-vehicle distance determining means 43 actively determines the white line recognition distance.

  FIG. 15 is a flowchart illustrating a procedure in which the driving support device 100 determines the target inter-vehicle distance. In FIG. 15, the description of the same steps as those in FIG. 7 is omitted. In step S21, the white line recognition distance determining unit 41 extracts the travel environment and determines the white line recognition distance according to the travel environment (S21). The subsequent steps are the same as in FIG.

  According to the present embodiment, as in the first embodiment, it is possible to prevent the preceding vehicle from being present within the white line recognition distance, and further, the white line recognition distance can be reduced according to the driving environment. And the acceptability of the driver can be improved.

  In the present embodiment, the night light is detected by turning on the headlight, but the white line recognition distance may be determined from the brightness around the vehicle. The brightness around the vehicle is detected from the shutter speed of the camera 11. For example, at night, when there is no vehicle headlamp and there are no street lamps in the vicinity, the shutter speed is slowed down to obtain the amount of light, so it is detected that the surroundings of the vehicle are dark, and the target inter-vehicle distance determination means 43 determines the white line recognition distance. Can be shortened.

  If the white line recognition distance can be increased as in the first embodiment, the white line is not blocked by the preceding vehicle, but some drivers may feel uncomfortable that the inter-vehicle distance increases even though the vehicle speed is slow. Therefore, in the present embodiment, a description will be given of the driving support device 100 that determines whether or not to execute the method of the first embodiment according to the driver's will (operation). Since whether or not the method of the first embodiment can be executed can be set according to the driver's will, for example, it can be set whether or not the driver increases the inter-vehicle distance according to the taste.

  FIG. 16 shows an example of the setting operation screen. When a predetermined operation is input using a keyboard or a voice input device, a setting operation screen is displayed on the navigation screen or the information display unit 20. In FIG. 16, “LKAS inter-vehicle distance limit setting” is displayed. On the other hand, the driver can select “valid” or “invalid”. A physical switch may be prepared on the instrument panel or the steering.

-Learning of a driver | operator's operation You may learn a driver | operator's operation instead of providing a setting operation screen like FIG. For example, when the target inter-vehicle distance longer than the temporary target distance is set as in the first embodiment, the driver performs an operation to shorten the inter-vehicle distance (for example, the set inter-vehicle distance (large distance, medium distance, small distance) The driver is likely to feel that the inter-vehicle distance is too long. Therefore, when such an operation is detected, setting a target inter-vehicle distance longer than the temporary target distance is prohibited.

  FIG. 13B shows a functional block diagram of the driving support device 100 in this embodiment. In FIG. 13B, the description of the same components as in FIG. The inter-vehicle distance increase / decrease prohibiting means 48 detects the operation of the driver and prohibits an increase in the target inter-vehicle distance or a decrease in the target inter-vehicle distance. That is, when a target inter-vehicle distance longer than the temporary target distance is set and the driver inputs an operation to shorten the inter-vehicle distance, the inter-vehicle distance increase / decrease prohibiting means 48 prohibits the increase of the target inter-vehicle distance, When the target distance is set as the target inter-vehicle distance and the driver inputs an operation for increasing the inter-vehicle distance, the inter-vehicle distance increase / decrease prohibiting means 48 permits the increase of the target inter-vehicle distance.

  FIG. 17 is a flowchart illustrating a procedure in which the driving support device 100 determines the target inter-vehicle distance. The flowchart of FIG. 17 is repeated every predetermined cycle time when a target inter-vehicle distance longer than the temporary target distance is set.

  The target inter-vehicle distance determining means 43 determines whether or not a target inter-vehicle distance that is longer than the temporary target distance is set (S410). When the target inter-vehicle distance that is longer than the temporary target distance is not set (No in S410), the process ends.

  When the target inter-vehicle distance longer than the temporary target distance is set (Yes in S410), the inter-vehicle distance increase / decrease prohibiting means 48 detects the operation of the set inter-vehicle distance (S420), and whether or not there is an operation for shortening the inter-vehicle distance. Is determined (S430).

  When there is an operation for shortening the inter-vehicle distance (Yes in S430), the inter-vehicle distance increase / decrease prohibiting unit 48 prohibits setting a target inter-vehicle distance longer than the temporary target distance (S440), and an operation for shortening the inter-vehicle distance is performed. If there is not (No in S430), the inter-vehicle distance increase / decrease prohibiting means 48 ends the process while setting the target inter-vehicle distance longer than the temporary target distance (S450).

  Therefore, according to the process of FIG. 17, it is not necessary to create a setting operation screen as shown in FIG.

  If the inter-vehicle distance increase / decrease prohibiting means 48 prohibits setting a target inter-vehicle distance that is longer than the temporary target distance, the target inter-vehicle distance determining means 43 continues to prohibit the increase control of the target inter-vehicle distance until the ignition is turned off. Thus, the target inter-vehicle distance can be prevented from becoming larger than the temporary inter-vehicle distance again until the ignition is turned off, and the driver can be prevented from feeling troublesome.

  According to the present embodiment, since the driver's intention (operation) is detected and whether or not the increase control of the target inter-vehicle distance is executed is switched, the driver's acceptability can be further improved.

It is a figure which shows the outline of the control procedure of a driving assistance system. It is an example of the block diagram of a driving assistance device. It is a figure which shows an example of the image data which a camera image | photographs. It is a figure which shows an example of constant speed driving | running | working and follow-up driving | running | working. It is a figure which shows an example of the relationship between a vehicle speed and the target inter-vehicle distance, a vehicle speed, and a white line recognition distance. It is an example of the functional block diagram of a driving assistance device. It is a flowchart figure which shows the procedure in which a driving assistance device determines the target inter-vehicle distance. It is a flowchart figure which shows the procedure in which a rolling assistance apparatus determines the target inter-vehicle distance. It is a figure which shows an example of the shielding of the white line by a preceding vehicle. It is a flowchart figure which shows the procedure in which a rolling assistance apparatus determines the target inter-vehicle distance. It is a figure which shows the example of detecting a shielding degree. It is a figure which shows an example of the relationship between the vehicle speed of a preceding vehicle, and the distance between vehicles. It is an example of the functional block diagram of a driving assistance device. It is a flowchart figure which shows the procedure in which a driving assistance device determines the target inter-vehicle distance. It is a flowchart figure which shows the procedure in which a driving assistance device determines the target inter-vehicle distance. It is a figure which shows an example of a setting operation screen. It is a flowchart figure which shows the procedure in which a driving assistance device determines the target inter-vehicle distance.

Explanation of symbols

9 LKA switch 11 Camera 12 White line recognition ECU
13 Radar device 14 ACC switch 15 Inter-vehicle distance control ECU
16 Power steering ECU
17 Engine ECU
18 Brake ECU
19 Meter ECU
41 White line recognition distance determination means 42 Temporary target distance determination means 43 Target inter-vehicle distance determination means 45 Shielding detection means 46 Shielding distance detection means

Claims (7)

Imaging means for photographing the front of the vehicle; lane marking recognition means for recognizing a lane marking that divides a lane from the image data captured by the imaging means;
Steering torque generating means for generating a steering torque for maintaining the lane based on the recognition result of the lane marking;
A vehicle travel control device that travels following a preceding vehicle detected in a traveling lane of the host vehicle and travels at a constant speed at a set vehicle speed when the preceding vehicle is not detected,
Lane line recognition distance storage means for storing a constant lane line recognition distance ;
A temporary target distance determining means for determining a temporary target inter-vehicle distance according to the vehicle speed of the host vehicle during follow-up traveling;
And occlusion detection means for detecting that the marking line recognition means the lane marker of the lane marker in the recognition distance for recognizing said preceding vehicle is shielded,
Shielding distance detecting means for detecting a shielding avoidance distance at which the preceding vehicle does not shield the lane marking, and
When the shielding detection means does not detect that the lane marking within the lane marking recognition distance is blocked by the preceding vehicle, the temporary target inter-vehicle distance is determined as the target inter-vehicle distance,
When the shielding detection unit detects that a lane marking within the lane marking recognition distance is blocked by the preceding vehicle, the lane marking recognition distance is set as an upper limit, and the shielding avoidance distance is set as a target inter-vehicle distance. A target inter-vehicle distance determining means for determining ;
A driving support device comprising: Driving environment detecting means for detecting the driving environment;
Recognition distance setting means for variably setting the lane marking recognition distance according to the traveling environment;
The driving support apparatus according to claim 1, further comprising: The driving environment detection means detects the driving environment from either headlight on, detection of botsdots, or shutter speed of the imaging means.
The travel support apparatus according to claim 2, wherein The occlusion detection means includes an image area of the preceding vehicle taken into the image data, the position information of the image area of the lane marker, the preceding vehicle is detected that shields the lane marker,
The driving support apparatus according to claim 1. The shielding detection means includes
The vehicle width of the preceding vehicle detected by the three-dimensional object detection means for detecting the three-dimensional object in front of the host vehicle;
The position of the vehicle in the width direction detected by the lane marking recognition means, or the width of the travel lane detected by the lane marking recognition means,
Detecting that the preceding vehicle is blocking a lane marking based on
The driving support apparatus according to claim 1. Having deceleration prediction means for predicting that the preceding vehicle decelerates using the road shape information;
When the deceleration prediction means predicts deceleration of the preceding vehicle,
The target inter-vehicle distance determining means adds the amount of increase determined by weighting the curvature radius of the curve, the curve length, and the current inter-vehicle distance to the target inter-vehicle distance ,
The driving support apparatus according to claim 1. Imaging means for photographing the front of the vehicle, lane marking recognition means for recognizing a lane marking that divides a lane from the image data captured by the imaging means, and steering torque for maintaining the lane based on the recognition result of the lane marking Steering torque generating means for generating, vehicle traveling control means for traveling following a preceding vehicle detected in the traveling lane of the host vehicle and traveling at a constant speed at a set vehicle speed when the preceding vehicle is not detected, and a constant lane marking A lane line recognition distance storage means for storing a recognition distance , and an inter-vehicle distance setting method for a driving support device, comprising:
A temporary target distance determining means determining a temporary target inter-vehicle distance according to the vehicle speed of the host vehicle during follow-up running;
A shielding detecting unit detecting that the preceding vehicle is shielding a lane marking within a certain lane marking recognition distance recognized by the marking recognition means;
A step of detecting a shielding avoidance distance at which the preceding vehicle stops shielding the lane markings;
The target inter-vehicle distance determining means determines the temporary target inter-vehicle distance as the target inter-vehicle distance when the shielding detecting means does not detect that the lane marking within the lane marking recognition distance is blocked by the preceding vehicle. ,
When the shielding detection unit detects that a lane marking within the lane marking recognition distance is blocked by the preceding vehicle, the lane marking recognition distance is set as an upper limit, and the shielding avoidance distance is set as a target inter-vehicle distance. A step to determine;
An inter-vehicle distance setting method characterized by comprising:

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