Vehicle control method and vehicle control device

Abstract

A controller (20) acquires a captured image of an area in front of a host vehicle (80), acquires host position information relating to the position of the host vehicle (80), and acquires map information including traffic signal position information relating to the positions of a vehicle traffic signal (90) and a pedestrian traffic signal (92). The controller (20) detects a preceding vehicle (81) by using a surroundings detection sensor (13) mounted on the host vehicle. The controller (20) then sets the inter-vehicle distance between the host vehicle (80) and the preceding vehicle (81), and causes the host vehicle to travel while following the preceding vehicle on the basis of the set inter-vehicle distance. When doing so, the controller (20) causes the inter-vehicle distance for instances where the vehicle traffic signal (90) within the captured image is blocked by the preceding vehicle (81) and is not recognized, and where the pedestrian traffic signal (92) within the captured image is recognized, to be set to an inter-vehicle distance that is within a range in which the pedestrian traffic signal (92) can be recognized and is less than the distance for instances where the vehicle traffic signal (90) can be recognized in the captured image.

Description

Vehicle control method and vehicle control device

[0001] The present invention relates to a vehicle control method and a vehicle control device.

[0002] Regarding automated driving of vehicles, a technology for making a vehicle follow a preceding vehicle is known (see, for example, Patent Document 1). The image processing device in Patent Document 1 recognizes a pedestrian traffic light, and when the pedestrian traffic light indicates a transition state in which the pedestrian can proceed, determines whether the vehicle can cross the intersection at its current speed, and if the vehicle can cross, increases its speed. If the vehicle cannot cross the intersection, the image processing device stops the vehicle at the stop line.

[0003] Japanese Patent Application Laid-Open No. 2020-82743

[0004] However, the device in Patent Document 1 performs processing assuming that the pedestrian traffic light is visible to the preceding vehicle, and there are cases where the pedestrian traffic light or the vehicular traffic light cannot be detected, for example, when the preceding vehicle is a large vehicle. In such cases, if the vehicle follows the preceding vehicle at a certain distance, there is a problem that the vehicular traffic light cannot be seen or the light display of the vehicular traffic light using the pedestrian traffic light cannot be estimated.

[0005] An object of the present invention is to provide a vehicle control method and a vehicle control device that are capable of estimating a vehicle traffic signal at least from a pedestrian traffic signal even when there is a preceding vehicle.

[0006] In one aspect of the present disclosure, a vehicle control method acquires a captured image of an area ahead of a host vehicle, acquires self-position information related to the location of the host vehicle, and acquires map information including traffic light position information related to the locations of a vehicular traffic light and a pedestrian traffic light linked to the vehicular traffic light. A surroundings detection sensor mounted on the host vehicle detects a leading vehicle traveling ahead of the host vehicle. A vehicle-to-vehicle distance between the host vehicle and the leading vehicle is then set, and the host vehicle is caused to follow the leading vehicle based on the set vehicle-to-vehicle distance. In this case, the vehicle-to-vehicle distance when the captured vehicle does not include a vehicular traffic light but does include a pedestrian traffic light is set to a distance within the captured image that is shorter than the distance when the vehicular traffic light is included in the captured image. This allows a vehicle-to-vehicle distance that at least allows the pedestrian traffic light to be seen, and allows the light display of the vehicular traffic light to be estimated based on the light display of the pedestrian traffic light.

[0007] 1 is a block diagram showing a schematic configuration of a vehicle control device mounted on a vehicle of the present embodiment. FIG. 2 is a flowchart showing a vehicle control method of the present embodiment. FIG. 3 is a diagram showing an example of a driving scene of the host vehicle when there is no preceding vehicle. FIG. 4 is a diagram showing an example of a driving scene of the host vehicle when a traffic light for vehicles can be recognized from image information. FIG. 5 is a diagram showing an example of a driving scene when both a traffic light for vehicles and a traffic light for pedestrians cannot be recognized from image information. FIG. 6 is a diagram showing an example of setting an inter-vehicle distance at which a traffic light for vehicles can be seen. FIG. 7 is a diagram showing an example of a driving scene when a traffic light for vehicles cannot be recognized from image information but a traffic light for pedestrians can be recognized and the host vehicle does not cross a stop line. FIG. 8 is a diagram showing an example of setting an inter-vehicle distance at which a traffic light for pedestrians can be seen.

[0008] An embodiment of the present disclosure will now be described. FIG. 1 is a block diagram showing a schematic configuration of a vehicle control device mounted on a vehicle (host vehicle) according to this embodiment. The vehicle control device 10 according to this embodiment includes a camera 11, a current position detection sensor 12, a surroundings detection sensor 13, a map database 14, an actuator 15, a controller 20, and the like. The camera 11 is an in-vehicle imaging device equipped with an imaging element such as a CCD (Charge Coupled Device), and is installed at a predetermined position on the host vehicle to capture images of objects around the host vehicle. The camera 11 particularly detects and captures images of objects ahead of the vehicle. Examples of objects to be detected include surrounding vehicles including a leading vehicle, and road signs including traffic lights and stop lines. Note that the camera 11 may be a combination of multiple in-vehicle cameras.

[0009] The current position detection sensor 12 is a sensor that detects the current position of the vehicle. An example of the current position detection sensor 12 is a receiver that receives satellite signals from a Global Navigation Satellite System (GNSS) to determine the current position.

[0010] The surroundings detection sensor 13 may be of various types, such as laser radar, millimeter-wave radar, ultrasonic radar, or laser range finder, or a combination of these may be used. The surroundings detection sensor 13 detects obstacles on the path of the vehicle and measures the distance to the obstacles. In this embodiment, the surroundings detection sensor 13 at least detects the position of a leading vehicle and measures the distance to the leading vehicle.

[0011] The map database 14 is a device that stores map information, and various storage devices such as semiconductor memory can be used. The map information stored in the map database 14 is information in which latitude and longitude coordinates are associated with points on a map. The map information includes road information defined by nodes and links connecting the nodes. The nodes or links included in the road information are also associated with traffic light position information, for example, regarding the positions of traffic lights installed at intersections. The traffic lights recorded in the traffic light position information include pedestrian traffic lights and vehicular traffic lights, and include the height of pedestrian traffic lights on the road, the position of the traffic light in the width direction of the road, and the height and position of vehicular traffic lights in the width direction of the road. The road information may also include the road type, road width, road shape, whether straight travel is permitted, priority of travel, whether overtaking is permitted (whether entering an adjacent lane is permitted), speed limits, other road-related information, the position of the intersection, the direction of approach to the intersection, the type of intersection, and other information regarding the intersection. In this embodiment, the vehicle control device 10 is illustrated as having the map database 14, but the map information may be stored in a predetermined external device (map data server) on the Internet.

[0012] The actuator 15 is a drive device that drives the vehicle based on the control of the controller 20, and includes, for example, an engine actuator, a brake hydraulic actuator, and a steering angle actuator. The engine actuator controls the engine driving force based on a drive control command from the controller 20. In the case of a hybrid vehicle, an engine actuator and a motor actuator may be used, and in the case of an electric vehicle, a motor actuator may be used. The brake hydraulic actuator is a hydraulic booster that controls the brake hydraulic braking force based on a braking control command from the controller 20. In the case of an electric vehicle that does not have a hydraulic booster, an electric booster may be used. The steering angle actuator is a steering angle control motor that controls the steering angle of the steered wheels based on a steering angle control command from the controller 20.

[0013] The controller 20 is a computer that controls the autonomous driving of the host vehicle. The controller 20 includes a storage device such as a semiconductor memory and an arithmetic circuit such as a CPU (Central Processing Unit). The arithmetic circuit of the controller 20 reads and executes programs stored in the storage device, thereby realizing various functions. Specifically, as shown in FIG. 1 , the controller 20 functions as an image acquisition unit 21, a map information acquisition unit 22, a vehicle position acquisition unit 23, a traffic light position acquisition unit 24, a preceding vehicle detection unit 25, a traffic light recognition unit 26, a following distance setting unit 27, and a driving control unit 28. Note that, in this example, the functional configurations of the image acquisition unit 21, the map information acquisition unit 22, the vehicle position acquisition unit 23, the traffic light position acquisition unit 24, the preceding vehicle detection unit 25, the traffic light recognition unit 26, the following distance setting unit 27, and the driving control unit 28 are realized by the arithmetic circuit of the controller 20 executing the programs. However, some or all of these functional configurations may be realized by individual hardware configurations.

[0014] The image acquisition unit 21 acquires the captured image input from the camera 11. The map information acquisition unit 22 acquires map information from the map database 14. Note that, although the present embodiment shows an example in which map information is acquired from the map database 14, map information recorded in a predetermined map data server may be acquired (downloaded) via the Internet.

[0015] The self-position acquisition unit 23 acquires self-position information from the current position detection sensor 12, and estimates the self-position (current position) of the vehicle on the map based on the longitude and latitude included in the self-position information and the map information recorded in the map database 14.

[0016] The traffic light position acquisition unit 24 acquires traffic light position information indicating the position of a traffic light from map information. The traffic light position information to be acquired is information regarding a traffic light ahead of the vehicle on a road along which the vehicle is scheduled to travel. The traffic light position acquisition unit 24 can identify the position of a traffic light ahead of the vehicle by having the vehicle position acquisition unit 23 estimate the vehicle's own position on the map. Note that traffic lights include vehicular traffic lights and pedestrian traffic lights linked to vehicular traffic lights. Note that a pedestrian traffic light linked to a vehicular traffic light is a traffic light in which the color of the vehicular traffic light and the color of the pedestrian traffic light are the same and change color at the same time or with a predetermined delay. In other words, it refers to a traffic light in which the color of the vehicular traffic light can be estimated from the color of the pedestrian traffic light. The position of the traffic light also includes the height positions of the vehicular traffic lights and the pedestrian traffic lights and their installation positions in the vehicle width direction.

[0017] The preceding vehicle detection unit 25 detects a preceding vehicle and its position relative to the host vehicle based on a signal input from the surroundings detection sensor 13. In addition to the surroundings detection sensor 13, the preceding vehicle may be detected using an image captured by the camera 11.

[0018] The signal recognition unit 26 recognizes vehicular traffic lights and pedestrian traffic lights in the captured image. Specifically, as described above, by estimating the position of the host vehicle, the position of the traffic light ahead of the host vehicle can be acquired from the traffic light position information. Furthermore, based on the position of the host vehicle on the road and the traffic light position information, it can estimate where in the captured image the image of the vehicular traffic light or the pedestrian traffic light will appear.

[0019] Incidentally, when there is a preceding vehicle ahead of the host vehicle, a vehicular traffic light or a pedestrian traffic light may be blocked by the preceding vehicle and not be visible in the captured image. The signal recognition unit 26 determines whether the vehicular traffic light is included in the captured image (i.e., detectable as an image) or whether the vehicular traffic light is not included in the captured image (i.e., undetectable as an image) due to blocking by the preceding vehicle. Similarly, the signal recognition unit 26 determines whether the pedestrian traffic light is included in the captured image (i.e., detectable as an image) or whether the pedestrian traffic light is not included in the captured image (i.e., undetectable as an image) due to blocking by the preceding vehicle. Hereinafter, when a traffic light (vehicular traffic light or pedestrian traffic light) is included in the captured image, it may be expressed as "the traffic light is recognized" or "the traffic light is recognizable."

[0020] The inter-vehicle distance setting unit 27 sets the inter-vehicle distance between the host vehicle and the preceding vehicle when the host vehicle is driven autonomously to follow the preceding vehicle. The inter-vehicle distance setting unit 27 sets the inter-vehicle distance based on the host vehicle's own position information, the position of the preceding vehicle, and the position of a recognizable traffic light. For example, when map information indicates that there is no traffic light within a predetermined distance range ahead of the host vehicle, that is, when the host vehicle is traveling on a road without traffic lights, the inter-vehicle distance setting unit 27 sets a normal inter-vehicle distance. The normal inter-vehicle distance is a distance based on the speed of the host vehicle, the speed limit of the road on which the host vehicle is traveling, etc. For example, the inter-vehicle distance is set in advance based on the speed of the host vehicle and the speed limit, and is stored in a storage device as reference inter-vehicle distance information. This allows the inter-vehicle distance setting unit 27 to set the inter-vehicle distance based on the speed of the host vehicle and the speed limit stored in the road information.

[0021] On the other hand, if the map information indicates that a traffic light is present within a predetermined distance range ahead of the host vehicle, the inter-vehicle distance setting unit 27 changes the inter-vehicle distance in the captured image depending on whether the traffic light is obstructed or not. If the vehicular traffic light can be recognized in the captured image, the inter-vehicle distance setting unit 27 sets a normal inter-vehicle distance as described above. In other words, if the host vehicle is following the preceding vehicle at a normal inter-vehicle distance and the vehicular traffic light can be recognized at that distance, the host vehicle continues autonomous driving, following the preceding vehicle at a normal inter-vehicle distance.

[0022] When a vehicular traffic light cannot be recognized in the captured image, the inter-vehicle distance setting unit 27 changes the inter-vehicle distance based on whether a pedestrian traffic light can be recognized in the captured image. In a situation where both a vehicular traffic light and a pedestrian traffic light cannot be recognized in the captured image, the inter-vehicle distance setting unit 27 sets a distance at which the vehicular traffic light can be recognized in the captured image. The distance at which the vehicular traffic light can be recognized can be calculated, for example, by trigonometry using the position of the camera 11 on the host vehicle, the distance to the detected leading vehicle, the height of the detected leading vehicle, the position (height) of the traffic light based on traffic light position information in the map information, the planar distance from the host vehicle's position to the traffic light in the map information, etc.

[0023] In a situation where a traffic light for vehicles cannot be recognized in the captured image but a traffic light for pedestrians can, the inter-vehicle distance setting unit 27 sets the inter-vehicle distance within a distance range in which the pedestrian traffic light can be recognized in the captured image, that is, within a range in which the pedestrian traffic light is included in the captured image. More specifically, the inter-vehicle distance setting unit 27 sets the inter-vehicle distance within a distance range in which the pedestrian traffic light can be recognized and equal to or greater than a predetermined minimum inter-vehicle distance. In other words, the inter-vehicle distance setting unit 27 sets a minimum inter-vehicle distance within a range in which the pedestrian traffic light is visible that is at least equal to or greater than the minimum inter-vehicle distance. This minimum inter-vehicle distance within a range in which the pedestrian traffic light is visible is shorter than the inter-vehicle distance set when the inter-vehicle distance is set so that the traffic light for vehicles is visible.

[0024] The driving control unit 28 outputs control commands related to the autonomous driving to the actuator 15, thereby driving the actuator 15 and implementing autonomous driving of the host vehicle. For example, the controller 20 of this embodiment generates a driving route for autonomous driving based on map information, and generates drive control commands (speed commands), braking control commands, and steering angle control commands to drive the host vehicle along the generated driving route, and outputs these to the actuator 15. At this time, if a leading vehicle is traveling ahead of the host vehicle, the controller 20 calculates each command value and outputs it to the actuator 15 so that the distance between the host vehicle and the leading vehicle becomes the distance set by the following distance setting unit 27.

[0025] Furthermore, the driving control unit 28 performs stop control based on the pedestrian traffic light when the host vehicle is traveling following the preceding vehicle at the set inter-vehicle distance. That is, the driving control unit 28 determines whether the host vehicle will cross a stop line when traveling following the preceding vehicle at the set inter-vehicle distance. The stop line may be detected by an image capture or the surroundings detection sensor 13, or the stop line ahead of the host vehicle and the distance to the stop line may be determined based on road information included in map information and the host vehicle's own position information. Here, if it is determined that the host vehicle will not cross the stop line, or if the stop line will be crossed but the pedestrian traffic light is green (or if the color of the vehicle traffic light estimated from the color of the pedestrian traffic light is green), the driving control unit 28 causes the host vehicle to travel following the preceding vehicle at the set inter-vehicle distance. On the other hand, if it is determined that the vehicle will cross the stop line and the color of the pedestrian signal is other than green (or if the color of the vehicle signal estimated from the color of the pedestrian signal is other than green), the driving control unit 28 outputs a braking control command to stop the vehicle at the stop line or to stop the vehicle within a specified range before the stop line.

[0026] [Vehicle Control Method] Next, the vehicle control method of this embodiment will be described. FIG. 2 is a flowchart of the vehicle control method of this embodiment. In this embodiment, when the autonomous driving process of the host vehicle is started, the driving control unit 28 of the controller 20 outputs a control command to the actuator 15 for driving along an autonomous driving route based on map information, and drives the host vehicle. In the autonomous driving process, the map information acquisition unit 22 acquires map information from the map database 14 (step S1: map acquisition step). Furthermore, the self-position acquisition unit 23 acquires self-position information from the current position detection sensor 12 to acquire (estimate) the host position on the map (step S2: self-position acquisition step). Note that the estimation of the host position in step S2 is continuously performed at a predetermined cycle. Then, the traffic light position acquisition unit 24 acquires traffic light position information for a traffic light located ahead of the host position estimated in step S2 from the map information (step S3: traffic light position identification step).

[0027] Furthermore, the image acquisition unit 21 acquires the captured image input from the camera 11 (step S4: image acquisition step). Note that the image capture process by the camera 11 is continuously performed at a predetermined cycle while the autonomous driving of the host vehicle is being performed.

[0028] Next, the signal recognition unit 26 performs a signal recognition process to recognize traffic lights (vehicle traffic lights and pedestrian traffic lights) in the captured image acquired in step S4 (step S5). In step S5, the traffic light recognition process may be performed every time a captured image is acquired in step S4, or the traffic light recognition process may be performed when the vehicle's own position approaches within a predetermined distance from the position of the traffic light indicated by the traffic light position information.

[0029] Next, the preceding vehicle detection unit 25 determines whether or not there is a preceding vehicle traveling ahead of the host vehicle based on the input signal from the surroundings detection sensor 13 (step S6: preceding vehicle detection step). In step S6, if the preceding vehicle detection unit 25 detects a preceding vehicle, it determines YES. Furthermore, if it determines that there is a preceding vehicle, the preceding vehicle detection unit 25 simultaneously detects the position of the preceding vehicle (distance from the host vehicle), as well as the height and width of the preceding vehicle.

[0030] If the determination in step S6 is NO (if there is no preceding vehicle), the driving control unit 28 generates control commands (drive control commands, braking control commands, steering angle control commands) based on the speed limit for each road and outputs them to the actuator 15. As a result, the host vehicle continues to travel by automatic driving while performing vehicle speed control based on the speed limit (step S7). Figure 3 is a diagram showing an example of a traveling scene of the host vehicle 80 when the determination in step S6 is NO (if there is no preceding vehicle). If the determination in step S6 is NO, it means that there is no preceding vehicle ahead of the host vehicle 80, and in this case, the host vehicle 80 travels by performing vehicle speed control according to the speed limit set for each road.

[0031] If step S6 returns YES, the inter-vehicle distance setting unit 27 determines whether the vehicular traffic light 90 has been recognized in the signal recognition process of step S5 (step S8). If step S8 returns YES (if the vehicular traffic light can be recognized from the image information), the inter-vehicle distance setting unit 27 sets a normal inter-vehicle distance (step S9). FIG. 4 is a diagram showing an example of a driving scene of the host vehicle 80 when step S8 returns YES. If step S8 returns YES, a leading vehicle 81 is present ahead of the host vehicle 80, but the leading vehicle 81 does not block the vehicular traffic light 90, and the color of the vehicular traffic light 90 can be recognized. In this case, the color of the vehicular traffic light 90 can be identified at a normal inter-vehicle distance, and it can be determined based on the color of the vehicular traffic light 90 whether the host vehicle can proceed beyond the stop line 91 or should stop. In other words, when the vehicle traffic light 90 is green, the vehicle can follow the preceding vehicle 81 and proceed beyond the stop line, and when the vehicle traffic light 90 is other than green, the vehicle can be gradually slowed down and stopped at the stop line 91 or within a specified range in front of the stop line 91 (including stopping behind the preceding vehicle 81), thereby preventing the vehicle from suddenly stopping at a stop line, etc.

[0032] If step S8 returns NO, the inter-vehicle distance setting unit 27 further determines whether a pedestrian traffic light is recognized in step S5 (step S10). If step S10 returns NO, that is, if neither the vehicular traffic light nor the pedestrian traffic light is recognized, the inter-vehicle distance setting unit 27 sets an inter-vehicle distance at which the vehicular traffic light 90 is recognized (step S11). FIG. 5 is a diagram showing an example of a driving scene of the host vehicle 80 when step S10 returns NO (when neither the vehicular traffic light 90 nor the pedestrian traffic light 92 is recognized from the image information). If step S10 returns NO, as shown in FIG. 5, the host vehicle 80 is blocked by a leading vehicle 81 in front of the host vehicle 80, and the vehicular traffic light 90 and the pedestrian traffic light 92 are not visible from the host vehicle 80. In this case, in step S11, the inter-vehicle distance setting unit 27 sets an inter-vehicle distance so that the vehicular traffic light 90 is recognized in the captured image.

[0033] 6 is a diagram showing an example of setting the following distance at which a vehicular traffic light 90 can be seen. In this example, it is assumed that the camera 11, the current position detection sensor 12, and the surroundings detection sensor 13 are installed in the same position in the subject vehicle 80, and the height of the installation position is H Ｃ , the distance from the front end of the vehicle 80 is L Ｃ For example, in FIG. 6, the height H of the vehicular traffic signal 90 is Ｓ is recorded in the traffic light position information. The horizontal distance L from the current position of the vehicle 80 to the traffic light 90 Ｓ０ can be calculated based on the traffic light position information. Therefore, the angle θ of the traffic light 90 as seen from the vehicle 80 is calculated as tan θ=(H Ｓ -H Ｃ ) / L Ｓ０ In addition, the height H of the preceding vehicle 81 can be calculated as follows. Ａ can be calculated based on the measurement values ​​detected by the surrounding detection sensor 13. Therefore, the distance between the host vehicle 80 and the preceding vehicle 81 is calculated as LX １ Then, tan θ = (H Ａ -H Ｃ ) / (L Ｃ +LX １) is satisfied, the vehicular traffic light 90 can be recognized in the captured image. １ , LX １ = (H Ａ -H Ｃ ) x L Ｓ０ / (H Ｓ -H Ｃ )-L Ｃ The above-mentioned inter-vehicle distance LX １ The calculation of the vehicle distance LX is an example, and is not limited to this. １ Alternatively, the following distance LX may be calculated: １ The variables used to calculate the following distance LX are not limited to those mentioned above, and other variables may be used, and a predetermined margin may be added to each variable to calculate the following distance LX.

[0034] If the answer to step S10 is YES, that is, if the vehicle traffic light 90 cannot be recognized but the pedestrian traffic light 92 can be recognized, the vehicle distance setting unit 27 determines whether the vehicle 80 will cross the stop line 91 when the vehicle distance is controlled within the range in which the pedestrian traffic light 92 can be recognized (step S12).

[0035] FIG. 7 is a diagram showing an example of a driving scene of the host vehicle 80 when step S10 is determined as YES and step S12 is determined as NO (when the vehicle traffic light 90 cannot be recognized from the image information, but the pedestrian traffic light 92 can be recognized, and the host vehicle does not cross the stop line). When step S10 is determined as YES, as shown in FIG. 7 , a leading vehicle 81 in front of the host vehicle 80 blocks the vehicle traffic light 90 from the host vehicle 80, but the pedestrian traffic light 92 is visible. In the scene shown in FIG. 7 , the distance from the host vehicle 80 to the stop line 91 is sufficiently secured, and even if the host vehicle 80 adjusts the inter-vehicle distance to the leading vehicle 81 and travels following the leading vehicle 81, the host vehicle 80 will not cross the stop line 91, and therefore step S12 is determined as NO. In this case, the inter-vehicle distance setting unit 27 sets the inter-vehicle distance L at least equal to the predetermined minimum inter-vehicle distance L within a range in which the pedestrian traffic light 92 can be recognized in the captured image. Ｘ０The inter-vehicle distance is set so that it is equal to or shorter than the inter-vehicle distance that can be recognized by the vehicular traffic signal 90 (step S13).

[0036] 8 is a diagram showing an example of setting the following distance at which a pedestrian traffic light 92 can be seen. For example, at an intersection, a pedestrian traffic light 92 is usually provided above a crosswalk on a road that intersects with the road on which the host vehicle is traveling. Therefore, as seen from the host vehicle 80, the pedestrian traffic light 92 is provided on the side of the road on which the host vehicle is traveling. In FIG. 8, the pedestrian traffic light 92 is located at a distance W from the side of the road on which the host vehicle 80 is traveling (for example, the left boundary line 93). Ｓ The distance W Ｓ is recorded in the traffic light position information. The horizontal distance L from the current position of the vehicle 80 to the pedestrian traffic light 92 Ｓ１ can be calculated based on the traffic light position information. Ｌ can be calculated based on the detection result by the surrounding detection sensor 13 or the self-position information. Therefore, the angle α of the pedestrian traffic light 92 as seen from the own vehicle 80 is expressed as tan α=(W Ｌ +W Ｓ ) / L Ｓ１ In addition, the vehicle width W of the preceding vehicle 81 can be calculated as follows. Ａ can be calculated based on the measurement values ​​detected by the surrounding detection sensor 13. Therefore, the distance between the host vehicle 80 and the preceding vehicle 81 is calculated as LX ２ Then, tan α = W Ａ / 2 (L Ｃ +LX ２ ) is satisfied, the pedestrian traffic light 92 can be recognized in the captured image. ２ , LX ２ =W Ａ ×L Ｓ１ / 2 (W Ｌ +W Ｓ )-L Ｃ The following distance setting unit 27 can calculate the following distance LX ２ and the preset minimum distance LX ０ Compared with LX２ ≦LX ０ If so, the minimum distance between vehicles LX ０ The following distance LX should be set ２ ' and LX ２ >LX ０ If so, the calculated inter-vehicle distance LX ２ The following distance LX should be set ２ The above inter-vehicle distance LX ２ The calculation of the vehicle distance LX is an example, and is not limited to this. １ Alternatively, the following distance LX may be calculated: ２ The variables used to calculate the vehicle distance LX are not limited to those mentioned above, and other variables may be used. A predetermined margin may be added to each variable to calculate the vehicle distance LX. ２ may be calculated.

[0037] If the determination in step S12 is NO, that is, if it is determined that the host vehicle 80 will cross the stop line 91 if it follows the preceding vehicle 81, the traveling control unit 28 determines whether the color of the pedestrian traffic light 92 is green (step S14). If the pedestrian traffic light 92 is green and the determination in step S14 is YES, the processing in step S13 is performed, and the inter-vehicle distance setting unit 27 sets the pedestrian traffic light 92 within a range in which the pedestrian traffic light 92 can be recognized in the captured image and at least within a predetermined minimum inter-vehicle distance L Ｘ０ The distance between vehicles is LX. ２ Set ´.

[0038] Furthermore, if the pedestrian traffic light 92 is not green and the determination in step S14 is NO, the driving control unit 28 generates a control command to stop the host vehicle 80 at the stop line 91 or within a predetermined range in front of the stop line 91. As a result, the host vehicle 80 gradually decelerates and stops toward the stop line 91 or in front of the stop line 91 (step S15).

[0039] The above-described steps S9, S11, and S13 correspond to the following distance setting step in the present disclosure. After these steps S9, S11, and S13, the cruise control unit 28 generates control commands (drive control command, braking control command, steering angle control command) to cause the host vehicle 80 to travel following the leading vehicle 81 at the set following distance, and outputs the generated control commands to the actuator 15 (step S16: cruise control step).

[0040] As a result, when a normal inter-vehicle distance is set in step S9, the host vehicle 80 travels following the preceding vehicle 81 with a normal inter-vehicle distance (for example, 5 m). In this case, the image captured by the camera 11 includes the vehicular traffic light 90. Therefore, even if the vehicular traffic light 90 changes color to a color other than green, the host vehicle 80 can stop at the stop line 91 or at a predetermined position in front of the stop line 91 with ample time to spare. Furthermore, in step S11, the inter-vehicle distance LX １ is set, the following distance LX １ The host vehicle 80 follows the leading vehicle 81 so as to maintain the above relation. In this case, as in step S9, the vehicular traffic light 90 is included in the image captured by the camera 11. Therefore, even if the vehicular traffic light 90 changes color to a color other than green, the host vehicle 80 can stop at the stop line 91 or at a predetermined position in front of the stop line 91 with ample time to maneuver.

[0041] Furthermore, in step S13, the inter-vehicle distance LX ２ When the distance LX′ is set, the distance LX′ is within the range where the pedestrian traffic light 92 is visible. ２ In this case, the pedestrian traffic light 92 is included in the captured image captured by the camera 11, and it is therefore possible to estimate the color of the vehicle traffic light 90 from the color of the pedestrian traffic light 92. Therefore, the controller 20 can grasp the color of the pedestrian traffic light 92 based on the captured image, and when the pedestrian traffic light 92 changes to a color other than green, it is possible to immediately proceed to step S15 and stop the host vehicle 80 at the stop line 91 or within a predetermined range before the stop line 91.

[0042] [Effects of the Present Embodiment] In the vehicle control device 10 of the present embodiment, the arithmetic circuit reads and executes a program stored in the storage device, thereby functioning as an image acquisition unit 21, a map information acquisition unit 22, a vehicle position acquisition unit 23, a leading vehicle detection unit 25, a traffic light recognition unit 26, a vehicle-to-vehicle distance setting unit 27, and a driving control unit 28. The image acquisition unit 21 acquires an image of at least the area ahead of the vehicle 80 captured by the camera 11 (step S4). The vehicle position acquisition unit 23 acquires vehicle position information related to the vehicle 80's position and estimates the vehicle's position on a map (step S2). The map information acquisition unit 22 acquires map information including traffic light position information related to the positions of the vehicular traffic light 90 and the pedestrian traffic light 92 linked to the vehicular traffic light 90 (step S1). The leading vehicle detection unit 25 detects the leading vehicle 81 using the surroundings detection sensor 13 mounted on the vehicle 80 (step S6). The inter-vehicle distance setting unit 27 sets the inter-vehicle distance based on the self-position information of the host vehicle 80, the position of the preceding vehicle 81, the position of the vehicular traffic light 90, and the position of the pedestrian traffic light 92 (steps S8 to S15). The driving control unit 28 causes the host vehicle 80 to drive following the preceding vehicle 81 based on the set inter-vehicle distance (step S17). When the preceding vehicle 81 is detected and the vehicular traffic light 90 is not recognized in the captured image but the pedestrian traffic light 92 is recognized in the captured image, the inter-vehicle distance setting unit 27 sets the inter-vehicle distance to a shorter distance than when the inter-vehicle distance is increased to a distance at which the vehicular traffic light 92 can be recognized, within a range at which the pedestrian traffic light 92 can be recognized in the captured image.

[0043] As a result, the host vehicle 80 can maintain a vehicle-to-vehicle distance that allows the pedestrian traffic light 92 to be seen, thereby estimating the light display of the vehicular traffic light 90 based on the light display of the pedestrian traffic light 92. Furthermore, since the light state of the vehicular traffic light 90 can be estimated based on the light state of the pedestrian traffic light 92, even if the host vehicle 80 detects a stop line 91 while following the leading vehicle 81, if the light state of the vehicular traffic light 90 is green, the host vehicle 80 can continue traveling beyond the stop line 91, thereby preventing the host vehicle 80 from suddenly stopping at the stop line 91. Furthermore, if the host vehicle 80 controls the vehicle-to-vehicle distance within a range where the vehicular traffic light 90 is visible without taking the pedestrian traffic light 92 into consideration, the vehicle-to-vehicle distance between the host vehicle 80 and the leading vehicle 81 may become large. In contrast, in this embodiment, when the vehicle-to-vehicle distance is controlled within a range where the pedestrian traffic light 92 is visible, a shorter vehicle-to-vehicle distance is set than when the vehicle-to-vehicle distance is increased to a distance where the vehicular traffic light 90 is visible. This prevents the distance between the host vehicle 80 and the leading vehicle 81 from becoming too large inadvertently.

[0044] In this embodiment, the inter-vehicle distance setting unit 27 sets at least the preset minimum inter-vehicle distance LX ０ The above-described inter-vehicle distances are set, thereby making it possible to prevent the host vehicle 80 from inadvertently approaching the leading vehicle 81.

[0045] In the present embodiment, in a situation where the host vehicle 80 is following a leading vehicle 81 and entering a stop line 91, if the vehicular traffic light 90 is not recognized in the captured image but the pedestrian traffic light 92 is recognized in the captured image, the travel control unit 28 causes the host vehicle 80 to cross the stop line 91 to follow the leading vehicle 81 if the pedestrian traffic light 92 is green, and causes the host vehicle 80 to stop at the stop line 91 or at a predetermined position in front of the stop line 91 if the pedestrian traffic light 92 is a color other than green. This makes it possible to estimate the color of the vehicular traffic light 90 from the color of the pedestrian traffic light 92, even when the vehicular traffic light 90 is not visible. Then, the host vehicle 80 is caused to travel following the leading vehicle 81 only when the pedestrian traffic light 92 is green, and is caused to stop at or in front of the stop line 91 if the pedestrian traffic light 92 is a color other than green. Furthermore, when the pedestrian traffic light 92 is green, the distance between vehicles is controlled within the range where the pedestrian traffic light 92 is visible, causing the vehicle 80 to follow the preceding vehicle 81, so there is no need to suddenly stop the vehicle 80 even if a stop line 91 is detected, and repeated sudden stops and starts of the vehicle 80 can be suppressed.

[0046] [Modifications] The present invention is not limited to the above-described embodiment, and includes the following modifications within the scope of achieving the object of the present invention. [Modification 1] In the above-described embodiment, when the vehicle traffic light 90 cannot be recognized in the captured image but the pedestrian traffic light 92 is recognized, the inter-vehicle distance setting unit 27 sets the inter-vehicle distance within a range where the pedestrian traffic light 92 is visible and within the minimum inter-vehicle distance L Ｘ０ The minimum distance between vehicles is set as above. Ｘ０ For example, when neither the vehicle traffic light 90 nor the pedestrian traffic light 92 can be recognized in the captured image, the inter-vehicle distance setting unit 27 sets an inter-vehicle distance at which the vehicle traffic light 90 can be recognized. Ｘ０ It may be determined whether the value is equal to or greater than the predetermined value.

[0047] [Modification 2] In the above embodiment, when neither the vehicular traffic light 90 nor the pedestrian traffic light 92 can be recognized in the captured image, the inter-vehicle distance setting unit 27 sets an inter-vehicle distance at which the vehicular traffic light 90 can be recognized. However, this is not limited to this. For example, when neither the vehicular traffic light 90 nor the pedestrian traffic light 92 can be recognized, the inter-vehicle distance setting unit 27 may set an inter-vehicle distance at which the pedestrian traffic light 92 can be seen. Alternatively, when neither the vehicular traffic light 90 nor the pedestrian traffic light 92 can be recognized, the inter-vehicle distance setting unit 27 may select the shorter inter-vehicle distance at which either the pedestrian traffic light 92 or the vehicular traffic light 90 can be recognized, as the inter-vehicle distance to be set.

[0048] 10...vehicle control device, 11...camera, 12...current position detection sensor, 13...surroundings detection sensor, 14...map database, 15...actuator, 20...controller, 21...image acquisition unit, 22...map information acquisition unit, 23...self-position acquisition unit, 24...signal position acquisition unit, 25...preceding vehicle detection unit, 26...signal recognition unit, 27...inter-vehicle distance setting unit, 28...driving control unit, 80...host vehicle, 81...preceding vehicle, 90...vehicle traffic light, 91...stop line, 92...pedestrian traffic light, 93...left boundary line.

Claims

A vehicle control method for controlling a vehicle by a computer, comprising: The computer Acquire a captured image of the area ahead of the vehicle; acquiring self-position information relating to the position of the vehicle; acquire map information including traffic light position information relating to the positions of a traffic light for vehicles and a traffic light for pedestrians linked to the traffic light for vehicles; a surroundings detection sensor mounted on the host vehicle detects a preceding vehicle traveling in front of the host vehicle; setting a vehicle-to-vehicle distance between the host vehicle and the preceding vehicle; causing the host vehicle to travel following the preceding vehicle based on the set inter-vehicle distance; A vehicle control method in which, when setting the inter-vehicle distance between the subject vehicle and the preceding vehicle, if the preceding vehicle is detected and the vehicle traffic light is not included in the captured image due to blocking by the preceding vehicle, but the pedestrian traffic light is included in the captured image, the computer sets the inter-vehicle distance to a range in which the pedestrian traffic light is included in the captured image and to a distance that is shorter than the distance when the vehicle traffic light is included in the captured image. 　 When setting the inter-vehicle distance between the host vehicle and the preceding vehicle, the computer sets the inter-vehicle distance to a distance equal to or greater than a predetermined minimum inter-vehicle distance. The vehicle control method according to claim 1 . 　 When the captured image does not include the vehicular traffic light but does include the pedestrian traffic light, the computer causes the host vehicle to cross the stop line to follow the preceding vehicle if the pedestrian traffic light is green, and causes the host vehicle to stop at the stop line or at a predetermined position before the stop line if the pedestrian traffic light is other than green. The vehicle control method according to claim 1 or 2. 　 When the computer is causing the host vehicle to travel following the preceding vehicle and both the vehicular traffic light and the pedestrian traffic light are not included in the captured image, the computer sets the inter-vehicle distance between the host vehicle and the preceding vehicle within a range in which the vehicular traffic light is included in the captured image. The vehicle control method according to claim 1 or 2. 　 an image acquisition unit that acquires a captured image of the area ahead of the host vehicle; a self-position acquiring unit that acquires self-position information relating to the position of the vehicle; a map information acquisition unit that acquires map information including traffic light position information relating to the positions of a traffic light for vehicles and a traffic light for pedestrians linked to the traffic light for vehicles; a preceding vehicle detection unit that detects a preceding vehicle traveling in front of the host vehicle using a surrounding detection sensor mounted on the host vehicle; a vehicle-to-vehicle distance setting unit that sets a vehicle-to-vehicle distance between the host vehicle and the preceding vehicle; a travel control unit that causes the host vehicle to travel following the preceding vehicle based on the set inter-vehicle distance, The vehicle control device, wherein when the preceding vehicle is detected and the vehicle traffic light is not included in the captured image due to blocking by the preceding vehicle, but the pedestrian traffic light is included in the captured image, the vehicle distance setting unit sets the vehicle distance to a range within which the pedestrian traffic light is included in the captured image and which is shorter than the distance when the vehicle traffic light is included in the captured image.

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