Driving control method and driving control device

Abstract

To decelerate a vehicle so that it can stop without crossing the stop line of its own lane even when the stop line of its own lane cannot be detected.SOLUTION: A controller 16 is configured to: detect, using a sensor mounted on an own vehicle 1, at least one stop line in front of the own vehicle 1 and lane boundary lines around the own vehicle 1 (S4, S6); determine whether or not the at least one stop line includes a stop line on an own lane in which the own vehicle 1 is traveling; and if the at least one stop line includes the stop line on the own lane, calculate, as a stop distance, a distance between the stop line on the own lane and a current position of the own vehicle 1 (S5), or if the at least one stop line does not include the stop line on the own lane, calculate, as the stop distance, a distance between the current position of the own vehicle 1 and a stop line with a distance between the stop line and the current position of the own vehicle along an extension direction of the own lane being shortest among the at least one stop line (S7).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a cruise control method and a cruise control device. [Background technology]

[0002] Patent Document 1 proposes a vehicle control device that extracts an image of a stop line from an image in front of the vehicle, calculates the distance to the stop line based on the position of the extracted stop line image, and warns the driver, assists driving, or intervenes in driving depending on the calculated distance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-63398 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the distance to the stop line is calculated based on the captured image, there is a risk that the stop line of the vehicle's own lane cannot be detected due to reasons such as obstruction by a preceding vehicle or blurring of the stop line. In this case, it becomes impossible to calculate the distance to the stop line (i.e., the target stopping position). Even if the stop line can be detected because the preceding vehicle has passed the stop line of the vehicle's own lane, if the vehicle is traveling following the preceding vehicle, it may get too close to the stop line and require a large deceleration to stop at the stop line. An object of the present invention is to decelerate a vehicle so that the vehicle can stop without crossing the stop line of the vehicle's lane, even when the stop line of the vehicle's lane cannot be detected. [Means for solving the problem]

[0005] A driving control method according to one aspect of the present invention is characterized in that a sensor mounted on the host vehicle detects at least one stop line ahead of the host vehicle and lane boundary lines around the host vehicle, determines whether the at least one stop line includes a stop line on the host vehicle's lane in which the host vehicle is traveling, calculates the distance between the stop line on the host vehicle's lane and the host vehicle's current position as a stopping distance if the at least one stop line includes a stop line on the host vehicle's lane, and calculates the distance between the host vehicle's current position and the stop line that is the shortest along the extension direction of the lane among the at least one stop line, and controls the host vehicle to decelerate based on the calculated stopping distance. [Effects of the Invention]

[0006] According to the present invention, even if the stop line of the own lane cannot be detected, the own vehicle can be decelerated so as to be able to stop without crossing the stop line of the own lane. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a vehicle equipped with a cruise control device according to an embodiment; [Figure 2] FIG. 2 is an explanatory diagram illustrating an outline of a driving control method according to an embodiment. [Figure 3] FIG. 2 is a block diagram illustrating an example of a functional configuration of a controller according to the first embodiment. [Figure 4] FIG. 4 is an explanatory diagram of a first example of a method for estimating a target stop position based on map information. [Figure 5] FIG. 10 is an explanatory diagram of a second example of a method for estimating a target stop position based on map information. [Figure 6] 10 is a flowchart of an example of a process for estimating a stopping distance. [Figure 7] FIG. 4 is a schematic diagram illustrating a stopping distance estimated by a stopping distance estimation unit. [Figure 8] 10 is a flowchart illustrating an example of processing in a control amount calculation unit. [Figure 9]FIG. 10 is a block diagram illustrating an example of a functional configuration of a controller according to a second embodiment. [Figure 10] 10 is a flowchart illustrating an example of a process for selecting a detected stop line in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are schematic and may differ from the actual product. Furthermore, the embodiments of the present invention shown below are examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention does not limit the structure, arrangement, etc. of component parts to those described below. The technical concept of the present invention can be modified in various ways within the technical scope defined by the claims.

[0009] (First embodiment) (composition) The host vehicle 1 is equipped with a driving control device 10 that supports the driving of the host vehicle 1. The driving control device 10 detects the driving environment around the host vehicle 1 and automatically controls the driving of the host vehicle 1 based on the detected driving environment, thereby supporting the driving of the host vehicle 1. For example, the driving assistance of the host vehicle 1 by the driving control device 10 may include autonomous driving control in which the host vehicle 1 is automatically driven without the involvement of an occupant (e.g., a driver). Also, for example, the driving assistance of the host vehicle 1 by the driving control device 10 may include automatic control of at least one of the driving force and braking force of the host vehicle 1.

[0010] The cruise control device 10 includes a positioning device 11, a map database 12, a navigation device 13, an external sensor 14, a vehicle sensor 15, a controller 16, and an actuator 17. In the drawings, the map database is referred to as a "map DB." The positioning device 11 measures the current position of the vehicle 1. The positioning device 11 may include, for example, a Global Positioning System (GNSS) receiver. The GNSS receiver is, for example, a Global Positioning System (GPS) receiver, and receives radio waves from multiple navigation satellites to measure the current position of the vehicle 1.

[0011] Map information is stored in the map database 12. The map information stored in the map database 12 may be, for example, map data for navigation that includes information on a road-by-road basis. Alternatively, for example, the map information stored in the map database 12 may be high-precision map data (hereinafter simply referred to as "high-precision map") that is suitable as map information for autonomous driving. A high-precision map is map data with higher precision than map data for navigation. The road information contained in a high-precision map includes lane-by-lane information that is more detailed than road-by-road information.

[0012] The navigation device 13 recognizes the current position of the vehicle 1 using the positioning device 11, and obtains map information for the current position from the map database 12. The navigation device 13 sets the driving route to the destination input by the occupant as the planned driving route of the vehicle, and provides route guidance to the occupant along this planned driving route. Furthermore, the navigation device 13 outputs information about the set planned driving route to the controller 16. When performing autonomous driving control, the controller 16 automatically drives the vehicle 1 so that the vehicle 1 travels along the planned driving route set by the navigation device 13.

[0013] The external sensor 14 detects various information (driving environment information) about the driving environment around the vehicle 1. For example, the external sensor 14 detects objects around the vehicle 1. The external sensor 14 detects the environment around the vehicle 1, such as objects present around the vehicle 1, the relative position between the vehicle 1 and the object, the distance between the vehicle 1 and the object, and the direction in which the object exists. The external sensor 14 outputs the detected information about the driving environment to the controller 16 as driving environment information. For example, the external sensor 14 detects the relative positions of other vehicles and targets around the vehicle 1 relative to the vehicle 1. Here, targets include, for example, traffic lights provided on the road on which the vehicle 1 is traveling, lines on the road surface (stop lines, lane boundaries, lane markings, etc.), curbs on the shoulders of the road, guardrails, etc.

[0014] The external sensor 14 may include a monocular camera such as a full HD color camera. The camera captures an image including a recognition target in the environment surrounding the vehicle 1, and outputs the captured image to the controller 16 as driving environment information. The external sensor 14 may also include a distance measuring device such as a laser range finder (LRF), radar, or a laser radar such as LiDAR (Light Detection and Ranging). The distance measuring device detects the relative position of the vehicle, which is determined by the relative distance and direction to an object present around the vehicle. The distance measuring device outputs the detected distance data to the controller 16 as driving environment information.

[0015] The vehicle sensor 15 detects various information (vehicle information) obtained from the host vehicle 1. The vehicle sensor 15 includes, for example, a vehicle speed sensor that detects the traveling speed (vehicle speed) of the host vehicle 1, a wheel speed sensor that detects the rotational speed of each tire equipped on the host vehicle 1, a three-axis acceleration sensor (G sensor) that detects the acceleration (including deceleration) in three axial directions of the host vehicle 1, a steering angle sensor that detects the steering angle of the steering wheel, a turning angle sensor that detects the turning angle of the steered wheels, a gyro sensor that detects the angular velocity generated in the host vehicle 1, a yaw rate sensor that detects the yaw rate, an accelerator sensor that detects the amount of operation of the accelerator pedal of the host vehicle 1, and a brake sensor that detects the amount of brake operation by the driver.

[0016] The controller 16 is an electronic control unit (ECU) that performs driving assistance control of the host vehicle 1. When performing driving assistance control of the host vehicle 1, the controller 16 automatically controls the driving of the host vehicle 1 based on the surrounding driving environment. The controller 16 includes a processor 20 and peripheral components such as a storage device 21. The processor 20 may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The storage device 21 may include a semiconductor storage device, a magnetic storage device, an optical storage device, etc. The storage device 21 may include memories such as a register, a cache memory, a ROM (Read Only Memory) used as a main memory device, and a RAM (Random Access Memory). The functions of the controller 16 described below are realized by, for example, the processor 20 executing a computer program stored in the storage device 21 .

[0017] The controller 16 may be formed by dedicated hardware for executing each of the information processes described below. For example, the controller 16 may include a functional logic circuit configured in a general-purpose semiconductor integrated circuit, such as a programmable logic device (PLD) such as a field-programmable gate array (FPGA).

[0018] The actuator 17 operates the accelerator opening and braking device of the host vehicle 1 in response to a control signal from the controller 16 to generate a driving force for driving the host vehicle 1 or a braking force for braking the host vehicle 1. The actuator 17 includes an accelerator opening actuator and a brake control actuator. The accelerator opening actuator controls the accelerator opening of the host vehicle 1. The brake control actuator controls the braking operation of the braking device of the host vehicle 1. The actuator 17 may also include a steering actuator that controls the steering direction and steering amount of the steering mechanism of the host vehicle 1. The actuator 17 may operate the steering mechanism of the host vehicle 1 in response to a control signal from the controller 16.

[0019] Next, a description will be given of the driving control of the host vehicle 1 by the controller 16. The driving control by the controller 16 includes speed control that detects a stop target position ahead of the host vehicle 1 and decelerates the host vehicle 1 toward the detected stop target position. 2 is an explanatory diagram illustrating an outline of a driving control method according to an embodiment. A road R on which the host vehicle 1 travels is provided with a host lane L1 on which the host vehicle 1 travels, an adjacent lane L2 on the left side of the host lane L1, and an adjacent lane L3 on the right side of the host lane L1. Furthermore, ahead of the host vehicle 1, there are provided a stop line Ls1 on the host lane L1, a stop line Ls2 on the adjacent lane L2, and a stop line Ls3 on the adjacent lane L3.

[0020] The controller 16 detects a stop line ahead of the host vehicle based on the driving environment information detected by the external sensor 14, calculates the distance between the position of the stop line and the current position of the host vehicle as a stopping distance, and performs deceleration control of the host vehicle 1 based on the calculated stopping distance. For example, the controller 16 decelerates the host vehicle 1 so that the vehicle speed of the host vehicle 1 becomes 0 when the stopping distance becomes 0. At this time, the external sensor 14 may not be able to detect the stop line Ls1 of the current lane L1.

[0021] For example, if a preceding vehicle is traveling ahead of vehicle 1 at the position of dashed line 2 in Figure 2, the preceding vehicle may block external sensor 14 from seeing stop line Ls1, making it impossible for external sensor 14 to detect stop line Ls1. If the stop line cannot be detected in this way, the distance to the target stopping position cannot be calculated. Also, even if the stop line can be detected later because the preceding vehicle passes the stop line, if the vehicle is following the preceding vehicle, it may get too close to the stop line and the deceleration required to stop at the stop line may be too great.

[0022] Therefore, the controller 16 detects at least one stop line Ls1, Ls2, and Ls3 ahead of the vehicle 1 based on the driving environment information detected by the external sensor 14. In the example of Fig. 2, not only the stop line Ls1 on the vehicle's lane L1 but also the stop lines Ls2 and Ls3 on the adjacent lanes L2 and L3 are detected. 2 illustrates a case in which the position Ps1 of the stop line Ls1 in the host vehicle's lane L1 and the position Ps2 of the stop line Ls2 in the adjacent lane L2 on the left are correctly recognized, but the position Ps3 of the stop line in the adjacent lane L3 on the right is incorrectly recognized. Now, let's assume that the stop line is incorrectly recognized as being at a position Ps3 that is closer in the direction of travel of the host vehicle 1 than the actual position of the stop line Ls3. Note that stop lines are not limited to being erroneously detected on lanes in the same direction of travel as the current lane L1. Stop lines may also be erroneously detected on lanes opposite the current lane L1, on median strips, and outside road boundaries.

[0023] Furthermore, the controller 16 detects lane boundaries around the vehicle 1 based on the driving environment information detected by the external sensor 14, and detects the vehicle's own lane L1 and adjacent lanes L2 and L3 based on the lane boundaries. The controller 16 determines whether the detected positions Ps1 to Ps3 of at least one stop line include the position Ps1 of the stop line Ls1 on the current lane L1. If the detected positions Ps1 to Ps3 of at least one stop line include the position Ps1 of the stop line Ls1 on the current lane L1, the controller 16 calculates the distance between the position Ps1 of the stop line Ls1 and the current position of the current vehicle 1 as the stopping distance.

[0024] On the other hand, if the external sensor 14 cannot detect the stop line Ls1 because a preceding vehicle in front of the vehicle 1 is blocking the stop line Ls1 or the stop line Ls1 is blurred (i.e., if the detected stop line positions Ps2, Ps3 do not include the position Ps1 of the stop line Ls1 on the vehicle's lane L1), the stopping distance is calculated as the distance between the stop line position Ps3 that is the shortest along the extension direction of the vehicle's lane L1 and the current position of the vehicle 1, among at least one of the stop line positions Ps2, Ps3. As described above, position Ps3 is a position that has been mistakenly recognized as a stop line on the adjacent lane L3. However, by calculating the distance to the closest position of the multiple recognized stop lines Ps2 and Ps3 to the vehicle 1 as the stopping distance, a safer stopping distance can be calculated even if the position of the stop line is mistakenly recognized.

[0025] As described above, the driving control method of the embodiment not only detects stop lines from the driving environment information detected by the external sensor 14, but also determines whether the detected stop lines include the stop line Ls1 on the host vehicle lane L1. If the detected stop lines do not include the stop line Ls1 on the host vehicle lane L1, the distance between the current position of the host vehicle 1 and the stop line that is the shortest along the extension direction of the host vehicle lane L1 among the detected stop lines is calculated as the stopping distance. This allows the vehicle to decelerate so that it can stop without crossing the stop line even if the stop line for the vehicle's lane cannot be detected. Also, even if the position of the stop line is incorrectly recognized, a safer stopping distance can be calculated.

[0026] Next, the driving control device 10 in the first embodiment will be described in more detail. Fig. 3 is a block diagram showing an example of the functional configuration of the controller 16 in the first embodiment. The controller 16 functions as an image recognition unit 30 and a control unit 31. The image recognition unit 30 detects at least one stop line ahead of the vehicle 1 and lane boundary lines around the vehicle 1 from an image captured by the camera of the external sensor 14 of the area ahead of the vehicle 1. The image recognition unit 30 includes a stop line detection unit 30a and a lane detection unit 30b.

[0027] The stop line detection unit 30a detects stop lines and their positions by analyzing the captured image captured by the camera. The lane detection unit 30b also analyzes the captured image captured by the camera to detect lane boundary lines, and detects the current lane, adjacent lanes, and their positions in the lane width direction. The lane detection unit 30b compares the positions of the stop lines detected by the stop line detection unit 30a with the positions of the detected lanes, and classifies the detected stop lines into stop lines for each lane, such as the stop line for the current lane and the stop line for the adjacent lane. The stop line detection unit 30a and the lane detection unit 30b may also detect stop lines, lane boundary lines, and their positions based on detection signals from a laser radar such as LiDAR in the external sensor 14.

[0028] The positioning device 11 is connected to a GNSS antenna installed outside the vehicle cabin, and estimates the current position and angle (attitude) of the vehicle 1 in a fixed coordinate system of map information stored in a map database 12. The navigation device 13 identifies the road on which the vehicle 1 is currently traveling from among the roads described in the map information based on the estimated current position. Furthermore, the navigation device 13 sets a destination through a user operation, searches for a route to the destination, and stores the route as a planned travel route along which the vehicle 1 will travel.

[0029] The control unit 31 includes a stopping distance estimation unit 31a and a control amount calculation unit 31b. The stopping distance estimation unit 31a estimates a target stopping position before an intersection on the planned driving route of the vehicle 1 based on map information, and compares the position of the stop line identified by the image recognition unit 30 with the target stopping position estimated from the map to calculate a stopping distance to be used for driving control (speed control) of the vehicle 1. The method of calculating the stopping distance by the stopping distance estimation unit 31a will be described in detail later. The control amount calculation unit 31b controls the accelerator and brake based on the stopping distance calculated by the stopping distance estimation unit 31a, and decelerates and stops the vehicle toward the stopping position. The speed control by the control amount calculation unit 31b will be described in detail later.

[0030] (Estimation of stopping location based on map information) Next, a method for estimating a target stopping position based on map information will be described. Fig. 4 is an explanatory diagram of a first example of a method for estimating a target stopping position based on map information. It is assumed that the host vehicle 1 is traveling toward an intersection C. Intersection C is represented by node points and link lines connecting them on the map 200, and holds information on the number of lanes of the intersecting road 202 as a road attribute value. In the example of Figure 4, the information on the number of lanes of the intersecting road 202, "6", is held.

[0031] At this time, the stop line of the road 204 on which the vehicle 1 is traveling is at least three lanes on each side before the node point 203 on the map. If a typical lane width is 3 m, this distance is 9 m. In reality, the stop line is usually placed further forward with a margin, so if the margin distance is 15 m, the target stopping position for intersection C shown in Figure 4 is estimated to be 24 m before the node point 203. The stopping distance estimation unit 31a estimates the distance between the target stopping position estimated as described above and the current position of the vehicle 1 measured by the positioning device 11 as the stopping distance to the nearest stop line ahead in the vehicle's lane.

[0032] Figure 5 is an explanatory diagram of a second example of a method for estimating a target stopping position based on map information. Figure 5 shows an intersection C similar to that shown in Figure 4. This intersection C is shown as maps 300 and 301, with each road on one side distinguished, and information on the number of lanes on each side is stored as an attribute value of the road. In the example shown in Figure 4, the information on the number of lanes on each side of roads 202a and 202b of intersecting road 202 is stored as "3." In many cases, link lines on a map are drawn to pass through approximately the center of the road. Therefore, the stopping distance estimation unit 31a estimates that the distance from the intersection 302 to the stop line at intersection C is the sum of half the width of a lane on each side of the road plus the aforementioned margin distance of 15 m. In the example of Figure 5, the estimated distance from the intersection 302 to the stop line is 19.5 m, which is half the width of a three-lane road (9 m on each side), or 4.5 m, plus the aforementioned margin distance of 15 m.

[0033] (Operation of the stopping distance estimation unit 31a) FIG. 6 is a flowchart of an example of a process in which the stopping distance estimation unit 31a estimates the stopping distance. In step S1, the stopping distance estimation unit 31a estimates the stopping distance to the stopping position at the next intersection on the road on which the vehicle 1 is traveling (i.e., the nearest intersection ahead on the planned traveling route of the vehicle 1) based on map information. In step S2, the stopping distance estimation unit 31a determines whether the stopping distance estimated in step S1 is equal to or greater than a predetermined threshold value. This threshold value is preferably set to the maximum distance at which the camera can stably detect the stop line, and may be, for example, 50 m.

[0034] If the stopping distance is equal to or greater than the threshold (step S2: Y), the process proceeds to step S3. If the stopping distance is not equal to or greater than the threshold (step S2: N), the process proceeds to step S4. In step S3, the stopping distance estimation unit 31a outputs the stopping distance estimated in step S1 (i.e., the distance between the target stopping position estimated based on the map information and the current position of the vehicle 1) as the stopping distance to the target stopping position, and then the process ends. In step S4, the stopping distance estimation unit 31a determines whether a stop line for the current lane has been detected. If a stop line for the current lane has been detected (step S4: Y), the process proceeds to step S5. If a stop line for the current lane has not been detected (step S4: N), the process proceeds to step S6.

[0035] In step S5, the stopping distance estimation unit 31a outputs the distance to the stop line of the current lane as the stopping distance, and then the process ends. In step S6, the stopping distance estimation unit 31a determines whether or not a stop line of an adjacent lane has been detected. If a stop line of an adjacent lane has not been detected (step S6: N), the process proceeds to step S3. In this case, the distance between the target stopping position estimated based on the map information and the current position of the vehicle 1 is output as the stopping distance to the target stopping position. The process then ends.

[0036] If a stop line of the adjacent lane has been detected (step S6: Y), the process proceeds to step S7. In step S7, the stopping distance estimation unit 31a calculates the distance between the current position of the host vehicle 1 and the stop line of the adjacent lane that has the shortest distance from the current position of the host vehicle 1 along the extension direction of the host lane. At this time, for example, the stopping distance estimation unit 31a calculates the distance along the extension direction of the host lane or the adjacent lane as the distance between the stop line and the host vehicle 1. The stopping distance estimation unit 31a outputs the calculated distance as the stopping distance. The process then ends.

[0037] 7 is a schematic diagram illustrating an example of a stopping distance estimated by the stopping distance estimation unit 31a. The horizontal axis of the graph in the figure represents the traveling position of the host vehicle 1, and the intersection with the vertical axis represents the actual position of the stop line. The vertical axis represents the stopping distance output from the stopping distance estimation unit 31a. The two-dot chain line 500, the one-dot chain line 501, and the dashed line 502 respectively indicate the stopping distance estimated based on map information, the stopping distance based on the detection of the stop line of the adjacent lane, and the stopping distance based on the detection of the stop line of the own lane.

[0038] It is believed that there is an error in predicting the stopping position based on map information, and therefore in the example of Figure 7, the stopping distance 500 based on the map information is estimated to be shorter than the actual stopping distance. Furthermore, since the stop line of the adjacent lane is offset from the stop line of the own lane, the stopping distance 501 based on the stop line of the adjacent lane is also estimated to be slightly shorter than the actual stopping distance. On the other hand, although the range of distance that can be detected based on the detection of the stop line of the own lane is limited (due to the influence of blocking by a preceding vehicle, etc.), the stopping distance 502 can be estimated with high accuracy.

[0039] In such a situation, the stopping distance output from the stopping distance estimation unit 31a is as shown by the solid line 503 in the figure. First, when the stopping distance based on the map information is equal to or greater than a threshold value (for example, 50 m), the stopping distance estimation unit 31a outputs the stopping distance 500 based on the map information. When the stopping distance based on the map information falls below a threshold, the distance 501 to the stop line of the adjacent lane detected at that time is output as the stopping distance. Furthermore, after the stop line of the own lane is detected, the distance 502 to the stop line of the own lane is output as the stopping distance.

[0040] In this way, stopping distance estimation unit 31a stores the position of the stop line (the stop line of the adjacent lane in the example of FIG. 7) detected by external sensor 14, and updates the stopping distance (stopping distance 501 in the example of FIG. 7) based on the stored position of the stop line and the current position of the host vehicle. When external sensor 14 detects a new stop line (the stop line of the host lane in the example of FIG. 7), it stores the position of the newly detected stop line, and updates the stopping distance (stopping distance 502 in the example of FIG. 7) based on the stored position of the stop line and the current position of the host vehicle.

[0041] Furthermore, after the stopping distance output from the stopping distance estimation unit 31a becomes smaller than 0 (becomes a negative value), that is, after the host vehicle 1 passes the stop line, the stopping distance is output as a negative value within a predetermined range (for example, set to approximately 5 m as the vehicle length). By doing so, the vehicle can be stopped even if it passes the stop line because it is unable to decelerate in time. After passing the predetermined range, the stopping distance calculated for the next intersection on the planned driving route is output.

[0042] When the stopping distance between the target stop position estimated based on the map information and the current position of the host vehicle 1 becomes less than a threshold value, the stopping distance estimation unit 31a may select only stop lines within a predetermined range from the target stop position estimated based on the map information from among the stop lines detected by the external sensor 14. The stopping distance estimation unit 31a may output, as the stopping distance, the distance between the current position of the host vehicle 1 and the stop line that has the shortest distance from the current position of the host vehicle 1 along the extension direction of the host lane from among the stop lines selected in this way. This allows the system to exclude false detections when the position of the stop line detected by the external sensor 14 is significantly different from the stop position estimated from the map information, thereby suppressing fluctuations in stopping distance due to false detections.

[0043] In addition, if the stopping distance between the target stopping position estimated based on map information and the current position of the vehicle 1 is less than a threshold value and a stop line in the vehicle's lane has not been detected, the stopping distance estimation unit 31a may calculate the stopping distance as the distance between the stop line on the lane in the same direction of travel as the planned driving route of the vehicle 1, which has the shortest distance along the extension direction of the lane between the stop line and the current position of the vehicle 1. This allows the stopping distance to be calculated only for lanes in the same direction as the vehicle's planned route, so the vehicle can stop in the correct position even at intersections where the position of the stop line along the extension of the lane varies depending on the route (for example, going straight, turning left, or turning right).

[0044] FIG. 8 is a flowchart of an example of the processing in the control amount calculation unit 31b. In step S10, the control amount calculation unit 31b determines whether the stopping distance output from the stopping distance estimation unit 31a is a distance calculated based on the stop line of the adjacent lane. If the stopping distance output from the stopping distance estimation unit 31a is not a distance calculated based on the stop line of the adjacent lane, that is, if the stopping distance is a distance calculated based on the stop line of the own lane or a distance estimated based on map information (step S10: N), the process proceeds to step S11. If the stopping distance output from the stopping distance estimation unit 31a is a distance calculated based on the stop line of the adjacent lane (step S10: Y), the process proceeds to step S12.

[0045] In step S11, the control amount calculation unit 31b calculates the deceleration to decelerate the host vehicle 1 so that the host vehicle 1 can be stopped in a stopping distance of 0. Then, the process ends. In step S12, the control amount calculation unit 31b calculates the deceleration so that the stopping distance is 0 and the vehicle slows down to a predetermined slow speed (for example, 4 km / h).

[0046] For example, as long as the stopping distance continues to be calculated based on the stop line of the adjacent lane, the host vehicle 1 may be allowed to continue traveling at least at a slow speed, and continue traveling even if the stopping distance calculated based on the stop line of the adjacent lane becomes equal to or less than a predetermined value. For example, the host vehicle 1 may be allowed to proceed beyond a point where the stopping distance becomes 0. This improves the visibility ahead of the host vehicle 1 due to changes in the position of the host vehicle 1 or changes in the situation over time, allowing the host vehicle 1 to travel slowly without stopping until the stop line of the host vehicle's lane is detected.

[0047] However, if the stop line of the vehicle's own lane cannot be detected due to blurring of the stop line, etc., there is a risk that the stop line of the vehicle's own lane will not be detected thereafter. Therefore, in step S13, the control amount calculation unit 31b determines whether the stopping distance is less than a threshold value (for example, minus 5 m). If the stopping distance is not equal to or less than the threshold (step S13: N), the process ends. In this case, the host vehicle 1 maintains the slow speed. On the other hand, if the stopping distance is equal to or less than the threshold (step S13: Y), the process proceeds to step S14. In step S14, the control amount calculation unit 31b decelerates the vehicle at a predetermined deceleration to stop the host vehicle 1. This makes it possible to prevent the host vehicle 1 from accidentally entering an intersection.

[0048] (Second embodiment) <Configuration> 9 is a block diagram showing an example of the functional configuration of the controller 16 in the second embodiment. The controller 16 in the second embodiment has a similar configuration to the controller 16 in the first embodiment, and the same components are denoted by the same reference numerals. The controller 16 in the second embodiment includes a crosswalk detection unit 30c and a traffic light detection unit 30d in addition to the configuration of the first embodiment. The crosswalk detection unit 30c detects the position of a crosswalk ahead of the vehicle 1 based on the driving environment information detected by the external sensor 14. The traffic light detection unit 30d detects the traffic light at the nearest intersection ahead in the vehicle's lane based on driving environment information detected by the external sensor 14 and road-to-vehicle communication, and obtains information on the signal displayed by the detected traffic light.

[0049] The stopping distance estimation unit 31a determines whether a crosswalk has been detected by the crosswalk detection unit 30c. If a crosswalk has been detected, any stop lines detected by the external sensor 14 that are farther away than the location of the crosswalk are determined to be erroneously detected stop lines and are excluded. The stopping distance estimation unit 31a calculates the stopping distance based on any stop lines detected by the external sensor 14 that are closer to the host vehicle 1 than the detected crosswalk.

[0050] Furthermore, the stopping distance estimation unit 31a changes the stopping distance depending on the detection state of the traffic signal. Specifically, after calculating the stopping distance by the process shown in Fig. 6, if the traffic signal is green, meaning "proceed," the stopping distance calculated by the process in Fig. 6 is changed to infinity. It may also be set to the distance from the current position of the vehicle 1 to the second intersection. By controlling the stopping distance in this way, the control amount calculation unit 31b can pass through the intersection without decelerating the vehicle 1.

[0051] FIG. 10 is a flowchart illustrating an example of a process for selecting a detected stop line in the second embodiment. In step S20, the stopping distance estimation unit 31a determines whether a crosswalk has been detected by the crosswalk detection unit 30c. If a crosswalk has been detected (step S20: Y), the process proceeds to step S22. If a crosswalk has not been detected (step S20: N), the process proceeds to step S21. In step S21, the stopping distance estimation unit 31a calculates the stopping distance based on the stop line detected by the external sensor 14 in the same manner as in the first embodiment.

[0052] In step S22, the stopping distance estimation unit 31a sequentially selects, one by one, from among the stop lines detected by the external sensor 14, stop lines to be subjected to determination (hereinafter referred to as "target stop lines"). In step S23, the stopping distance estimation unit 31a compares the distance from the current position of the vehicle 1 to the target stop line with the distance from the current position of the vehicle 1 to the crosswalk. If the target stop line is located in front of the crosswalk (step S23: Y), the process proceeds to step S25. If the target stop line is located farther from the vehicle 1 than the crosswalk (step S23: N), the process proceeds to step S24. In step S24, the stopping distance estimation unit 31a excludes the target stop line from the candidates for the stop line for which the stopping distance is to be calculated, and then the process proceeds to step S25.

[0053] In step S25, the stopping distance estimation unit 31a determines whether all stop lines detected by the external sensor 14 have been selected as target stop lines. If there are still stop lines that have not been selected as target stop lines (step S25: N), the process returns to step S22. In step S22, the stopping distance estimation unit 31a selects one of the stop lines that has not yet been selected as a target stop line, and the process proceeds to step S23. If all stop lines detected by the external sensor 14 are selected as target stop lines (step S25: N), the process proceeds to step S21. In step S21, the stopping distance is calculated based on the stop lines that were not excluded in step S24.

[0054] (Effects of the embodiment) (1) The controller 16 detects at least one stop line ahead of the vehicle 1 and lane boundary lines around the vehicle 1 using a sensor mounted on the vehicle 1, determines whether or not the at least one stop line includes a stop line on the lane in which the vehicle 1 is traveling, and if the at least one stop line includes a stop line on the lane in which the vehicle 1 is traveling, calculates the distance between the stop line on the lane in which the vehicle 1 is traveling and the current position of the vehicle 1 as the stopping distance, and if the at least one stop line does not include a stop line on the lane in which the vehicle 1 is traveling, calculates the distance between the stop line that is the shortest distance along the extension direction of the lane in which the vehicle 1 is traveling and the current position of the vehicle 1 as the stopping distance, and controls the deceleration of the vehicle 1 based on the calculated stopping distance. This allows the system to detect stop lines in adjacent lanes in addition to the stop line in the vehicle's own lane, and if the stop line in the vehicle's own lane cannot be detected, the distance to the stop line in the adjacent lane that has the shortest distance between the vehicle's current position and the vehicle 1 along the extension direction of the lane is used as the stopping distance, so that the vehicle can safely slow down and stop at the stop line even if the stop line in the vehicle's own lane is blocked by a preceding vehicle.

[0055] (2) If at least one stop line does not include a stop line on the vehicle's own lane, the controller 16 may calculate the stopping distance as the distance between the stop line on the lane that has the shortest distance along the extension direction of the lane between the vehicle and the current position of the vehicle 1, among the stop lines on the lane that are in the same direction of travel as the planned travel route, which is the route along which the vehicle 1 is planned to travel. This allows the vehicle to stop in the correct position even at intersections where the position of the stop line along the direction of the lane varies depending on the route (for example, going straight, turning left, or turning right).

[0056] (3) The controller 16 may calculate an estimated distance from the current position of the vehicle 1 to the nearest stop line ahead in the vehicle's lane based on map information including the position information of the stop line. If the estimated distance is equal to or greater than a threshold, the controller 16 may perform deceleration control of the vehicle 1 based on the estimated distance, and if the estimated distance is less than the threshold, the controller 16 may perform deceleration control of the vehicle 1 based on the stopping distance. This allows the location of the stop line to be predicted to some extent from map information, making it possible to start decelerating in advance from a long distance where the stop line cannot be detected.Furthermore, although detection of the stop line by the sensor becomes unstable over long distances, at such long distances, by using a stopping distance calculated based on map information rather than the sensor, it is possible to start deceleration stably.

[0057] (4) Based on map information containing information about the intersection of roads that intersect with each other, the controller 16 may estimate that the position of the stop line is a position a predetermined distance before the intersection in the traveling direction of the vehicle 1. In this way, the position of the stop line is estimated to be before the intersection (the intersection of roads) listed in the map information, so a realistic stopping distance can be calculated even when a general navigation map that does not list stop positions is used, when stop line position information is missing from the high-precision map, or when the accuracy of the self-position estimation based on the high-precision map is not high.

[0058] (5) The controller 16 may set the predetermined distance longer when the number of lanes on the intersecting road intersecting the road on which the vehicle 1 is traveling is large compared to when the number of lanes is small. This allows the stop line to be set accordingly closer when the intersecting road has many lanes.

[0059] (6) The controller 16 may store the position of the stop line detected by the sensor, and update the stopping distance based on the stored position of the stop line and the current position of the vehicle 1 until a new stop line is detected by the sensor. By storing the position of a stop line once detected in this way, the stopping distance can be calculated stably even if the stop line cannot be detected continuously.

[0060] (7) The controller 16 may estimate the position of the closest stop line ahead in the vehicle lane from the current position of the vehicle 1 based on map information including the position information of the stop line, and may calculate the stopping distance based on at least one stop line within a predetermined range from the estimated position of the stop line. This means that if the position of the stop line detected by the sensor deviates significantly from the stop position predicted based on map information, the detection result can be ignored as a false detection, thereby reducing fluctuations in stopping distance due to false detection.

[0061] (8) When the controller 16 controls deceleration of the vehicle 1 using the distance between a stop line other than the stop line on the vehicle's lane and the current position of the vehicle 1 as the stopping distance, the vehicle 1 may travel at a predetermined speed until a stop line on the vehicle's lane is detected, even if the stopping distance is less than a predetermined value. This allows the vehicle to pass at a slow speed without stopping at a point where the stopping distance is 0, even if the stopping distance is calculated based on the stop line of an adjacent lane, and therefore allows the vehicle to proceed to the stop line of the vehicle's own lane without stopping in the wrong place.

[0062] (9) The controller 16 may use a sensor to detect a crosswalk ahead of the vehicle 1, and calculate the stopping distance based on at least one stop line that is closer to the vehicle 1 than the detected crosswalk. This ignores stop lines detected farther away than the crosswalk, preventing incorrect calculation of stopping distances even if a horizontal line, such as a bicycle crossing zone attached to a crosswalk, is mistakenly detected as a stop line.

[0063] (10) The controller 16 may detect a traffic signal at an intersection with a stop line, and when the traffic signal is green, set the stopping distance to a predetermined value or more, or to the distance from the current position of the vehicle 1 to the second intersection. This allows the stopping distance to be set to infinity or the distance to the second intersection when the traffic light is green, so that the vehicle can pass through the stop line regardless of the accuracy of stop line detection. [Explanation of symbols]

[0064] 1...Own vehicle, 10...cruising control device, 11...positioning device, 12...map database, 13...navigation device, 14...external sensor, 15...vehicle sensor, 16...controller, 17...actuator, 20...processor, 21...storage device, 30...image recognition unit, 30a...stop line detection unit, 30b...lane detection unit, 30c...pedestrian crossing detection unit, 30d...traffic light detection unit, 31...control unit, 31a...stopping distance estimation unit, 31b...control variable calculation unit

Claims

1. detecting at least one stop line ahead of the host vehicle and lane boundary lines around the host vehicle using a sensor mounted on the host vehicle; determining whether the at least one stop line includes a stop line on a lane in which the host vehicle is traveling; If the at least one stop line includes a stop line on the own lane, calculate the distance between the stop line on the own lane and the current position of the host vehicle as a stopping distance, and if the at least one stop line does not include a stop line on the own lane, calculate the distance between the stop line that is the shortest distance from the current position of the host vehicle along the extension direction of the own lane among the at least one stop line and the current position of the host vehicle as a stopping distance, performing deceleration control of the host vehicle based on the calculated stopping distance; calculating an estimated distance from the current position of the vehicle to the nearest stop line ahead in the vehicle lane based on map information including position information of the stop line; When the estimated distance is equal to or greater than a threshold, deceleration control of the host vehicle is performed based on the estimated distance, and when the estimated distance is less than the threshold, deceleration control of the host vehicle is performed based on the stopping distance. A driving control method characterized by:

2. A sensor mounted on a vehicle detects at least one stop line ahead of the vehicle and lane boundaries around the vehicle; determining whether the at least one stop line includes a stop line on a lane in which the host vehicle is traveling; If the at least one stop line includes a stop line on the own lane, calculate the distance between the stop line on the own lane and the current position of the host vehicle as a stopping distance, and if the at least one stop line does not include a stop line on the own lane, calculate the distance between the stop line that is the shortest distance from the current position of the host vehicle along the extension direction of the own lane among the at least one stop line and the current position of the host vehicle as a stopping distance, performing deceleration control of the host vehicle based on the calculated stopping distance; Based on map information including stop line position information, the position of the nearest stop line ahead on the vehicle's lane is estimated from the current position of the vehicle; calculating the stopping distance based on a stop line within a predetermined range from the estimated position of the stop line among the at least one stop line; A driving control method characterized by:

3. A sensor mounted on the vehicle detects at least one stop line ahead of the vehicle and lane boundaries around the vehicle; determining whether the at least one stop line includes a stop line on a lane in which the host vehicle is traveling; If the at least one stop line includes a stop line on the own lane, calculate the distance between the stop line on the own lane and the current position of the host vehicle as a stopping distance, and if the at least one stop line does not include a stop line on the own lane, calculate the distance between the stop line that is the shortest distance from the current position of the host vehicle along the extension direction of the own lane among the at least one stop line and the current position of the host vehicle as a stopping distance, performing deceleration control of the host vehicle based on the calculated stopping distance; When deceleration control of the host vehicle is performed based on the distance between a stop line other than the stop line on the host lane and a current position of the host vehicle as the stopping distance, the host vehicle travels at a predetermined speed until the stop line on the host lane is detected even if the stopping distance becomes equal to or less than a predetermined value, and stops the host vehicle when the stopping distance becomes equal to or less than a threshold value smaller than the predetermined value. A driving control method characterized by:

4. The driving control method according to any one of claims 1 to 3, characterized in that, if the at least one stop line does not include a stop line on the vehicle's lane, the stopping distance is calculated as the distance between the current position of the vehicle and a stop line on a lane in the same traveling direction as the direction of a planned driving route, which is the route on which the vehicle is planned to travel, that has the shortest distance along the extension direction of the lane between the current position of the vehicle and the stop line.

5. 2. The cruise control method according to claim 1, wherein, based on the map information having information on an intersection of roads intersecting each other, a position a predetermined distance before the intersection in the traveling direction of the vehicle is estimated to be the position of the stop line.

6. 6. The cruise control method according to claim 5, wherein the predetermined distance is set longer when the number of lanes of an intersecting road intersecting the road on which the host vehicle is traveling is large compared to when the number of lanes of the intersecting road is small.

7. storing the position of the stop line detected by the sensor; updating the stopping distance based on the stored position of the stop line and the current position of the vehicle until a new stop line is detected by the sensor; 7. The method for controlling driving according to claim 1.

8. detecting a crosswalk ahead of the vehicle by the sensor; calculating the stopping distance based on a stop line that is closer to the host vehicle than the detected pedestrian crossing among the at least one stop line; 8. The method for controlling travelling according to claim 1.

9. A cruise control method according to any one of claims 1 to 8, characterized in that a traffic signal at an intersection where the stop line is installed is detected, and when the traffic signal is green, the stopping distance is set to a predetermined value or more, or to a distance from the current position of the vehicle to the next intersection after the intersection.

10. A sensor mounted on the vehicle; a controller that detects at least one stop line ahead of the host vehicle and lane boundary lines around the host vehicle using the sensor, determines whether the at least one stop line includes a stop line on the host vehicle's lane, and if the at least one stop line includes a stop line on the host vehicle's lane, calculates a stopping distance between the stop line on the host vehicle's lane and the current position of the host vehicle, and if the at least one stop line does not include a stop line on the host vehicle's lane, calculates a stopping distance between the stop line that is the shortest distance from the current position of the host vehicle along the extension direction of the host lane and the current position of the host vehicle, and performs deceleration control of the host vehicle based on the calculated stopping distance; Equipped with The controller calculating an estimated distance from the current position of the vehicle to the nearest stop line ahead in the vehicle lane based on map information including position information of the stop line; When the estimated distance is equal to or greater than a threshold, deceleration control of the host vehicle is performed based on the estimated distance, and when the estimated distance is less than the threshold, deceleration control of the host vehicle is performed based on the stopping distance. A driving control device characterized by:

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