Driving assistance method and driving assistance device

Abstract

In the present invention, when a vehicle (V1) is to turn right or left at an intersection (C) in which traffic lights (TL1, TL2) and a crosswalk (Z2) are provided, the vehicle (V1) stops before the intersection (C) in accordance with a stop signal displayed by the traffic lights (TL1, TL2). When there is no other vehicle that turning right or left in the same direction as the travel direction of the vehicle (V1) in front of the vehicle (V1), a detection area (A1) for detecting a pedestrian (H1) that can enter the crosswalk (Z2) in the travel direction is set. When the pedestrian (H1) is present in the detection area (A1) and the stop signal displayed by the traffic lights (TL1, TL2) is switched to a proceed signal, the stopped state of the vehicle (V1) is maintained for a predetermined time from the display of the proceed signal, or the vehicle (V1) is made to start and travel to a target stop position in front of the crosswalk (Z2) at a predetermined acceleration before the elapse of the predetermined time from the display of the proceed signal.

Description

Driving support method and driving support device

[0001] The present invention relates to a driving assistance method and a driving assistance device.

[0002] A vehicle driving assistance device is known that, when a pedestrian is present within a predetermined range from the sidewalk edge of a crosswalk ahead of the vehicle in the direction of travel, and if it is determined that the pedestrian is facing the crosswalk, drives the vehicle to the front of the crosswalk and stops the vehicle; if the pedestrian is crossing the crosswalk, the vehicle does not start moving until the pedestrian has finished crossing the crosswalk; and if the pedestrian is not crossing the crosswalk, the vehicle does not start moving until a predetermined time has passed (Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2006-244295

[0004] In the above-mentioned conventional technology, the deceleration when stopping a vehicle before a crosswalk is set to the same value as when the vehicle enters the intersection without stopping, even when the traffic light at the intersection switches from a stop signal to a go signal and the vehicle starts moving from a stopped state to enter the intersection. Therefore, in the above-mentioned conventional technology, when the traffic light switches from a stop signal to a go signal and the vehicle enters the intersection, the deceleration may be set such that the vehicle's behavior changes relatively significantly before the crosswalk, just as in the case when the vehicle enters the intersection without stopping. This change in behavior can cause pedestrians who are about to cross the crosswalk to hesitate to enter the crosswalk.

[0005] The problem to be solved by the present invention is to provide a driving assistance method and a driving assistance device that can prevent pedestrians who are about to cross a crosswalk from hesitating to enter the crosswalk.

[0006] This invention solves the above problem by setting a detection range for detecting pedestrians who may enter the crosswalk in the direction of travel when a vehicle stops before an intersection in response to a stop signal displayed by a traffic light and there are no other vehicles ahead of the vehicle turning right or left in the same direction as the vehicle's direction of travel, and by maintaining the vehicle stopped for a predetermined time after the go signal is displayed when a pedestrian is present within the detection range and the stop signal displayed by the traffic light changes to a go signal, or by starting the vehicle before the predetermined time has elapsed after the go signal is displayed and driving it at a predetermined acceleration to a target stopping position in front of the crosswalk.

[0007] According to the present invention, it is possible to prevent pedestrians who are about to cross a crosswalk from hesitating to enter the crosswalk.

[0008] 6 is a block diagram showing an example of an embodiment of a driving assistance system according to the present invention. FIG. 6 is a plan view (part 1) showing an example of a driving scene in which driving assistance is performed by the driving assistance system of FIG. 1. FIG. 6 is a plan view (part 2) showing an example of a driving scene in which driving assistance is performed by the driving assistance system of FIG. 1. FIG. 6 is a plan view (part 3) showing an example of a driving scene in which driving assistance is performed by the driving assistance system of FIG. 1. FIG. 6 is a plan view (part 1) showing another example of a driving scene in which driving assistance is performed by the driving assistance system of FIG. 1. FIG. 6 is a plan view (part 2) showing another example of a driving scene in which driving assistance is performed by the driving assistance system of FIG. 1. FIG. 6 is a plan view (part 3) showing an example of a driving scene in which driving assistance is performed by the driving assistance system of FIG. 6.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, it is assumed that in countries with laws stipulating left-hand traffic, vehicles drive on the left side of the road. In countries with laws stipulating right-hand traffic, vehicles drive on the right side of the road, so the terms right and left in the following description should be interpreted as symmetrical.

[0010] [Configuration of Driving Assistance System] Fig. 1 is a block diagram showing an example of an embodiment of a driving assistance system according to the present invention. The driving assistance system drives a vehicle from its current position to a destination set by the vehicle's occupant through autonomous driving control. Autonomous driving control is the autonomous control of the vehicle's driving operations, and driving operations include all driving operations such as acceleration, deceleration, starting, stopping, and steering.

[0011] 1, a driving assistance system 10 of this embodiment includes an imaging device 11, a distance measuring device 12, an on-board sensor 13, a map database 14, an actuator 15, and a driving assistance device 20. The devices that make up the driving assistance system 10 are communicably connected via a CAN (Controller Area Network) or other on-board LAN, and exchange information with each other.

[0012] The imaging device 11 is a camera equipped with an imaging element such as a CCD, and captures images of objects around the vehicle to generate an image including the objects. The imaging device 11 may be an infrared camera, a stereo camera, or the like. A plurality of imaging devices 11 are provided on the front grille, side mirrors, rear bumper, etc. of the vehicle to reduce blind spots where the objects cannot be captured.

[0013] The distance measuring device 12 detects the relative distance and relative speed between the vehicle and an object. The distance measuring device 12 includes a laser radar, a millimeter wave radar, a LiDAR (Light Detection and Ranging) unit, etc. A plurality of distance measuring devices 12 are provided on one vehicle to prevent blind spots where an object cannot be detected.

[0014] The objects detected by the imaging device 11 and the distance measuring device 12 are objects that exist on the road and its surroundings, including lane boundaries, center lines, road markings, medians, guardrails, curbs, road signs, traffic lights, crosswalks, etc. The objects also include obstacles that may affect the driving of the vehicle, such as other automobiles (other vehicles), motorcycles, bicycles, pedestrians, etc. The vehicle (host vehicle) is not particularly limited as long as it can be equipped with the driving assistance system 10.

[0015] The driving assistance device 20 acquires image information from the imaging device 11 and acquires position information of objects from the distance measuring device 12, and recognizes objects around the vehicle and the driving environment. The driving assistance device 20 acquires information at predetermined time intervals (for example, every 0.1 to 1 millisecond). The driving assistance device 20 may recognize the driving environment by integrating or synthesizing the information acquired from the imaging device 11 and the distance measuring device 12.

[0016] The on-board sensors 13 detect the vehicle's driving state. The on-board sensors 13 include a vehicle speed sensor, an acceleration sensor, a yaw rate sensor, a steering angle sensor, and the like. Any known sensor can be used without any particular limitations, and the arrangement and number of sensors can be set appropriately within a range that allows the vehicle's driving state to be appropriately detected. The on-board sensors 13 also include a positioning system that detects the current position of the vehicle. The positioning system calculates the current position of the vehicle based on radio waves received from a GPS (Global Positioning System) satellite, for example. The driving assistance device 20 acquires the detection results of each sensor at predetermined time intervals (for example, every 0.1 to 1 millisecond).

[0017] The map database 14 is a storage medium that stores map information and is provided inside or outside the vehicle. The driving assistance device 20 acquires map information from the map database 14 as needed. The map information includes information on nodes corresponding to specific points on roads (such as intersections) where the vehicle's direction of travel changes, and links corresponding to road sections connecting the nodes. The node information includes location information and information on entering and exiting intersections, and the link information includes road width, road curvature radius, road shoulder structures, road traffic regulations, etc. The map information may be high-precision map information that includes road information for each lane, as well as information on structures, signs, traffic lights, and the like around the road.

[0018] The actuator 15 is a device that converts an electrical control signal input from the driving assistance device 20 into mechanical work, and includes a servo motor, a hydraulic motor, a hydraulic cylinder, etc. The actuator 15 operates the drive device and steering device of the vehicle.

[0019] The driving assistance device 20 controls and cooperates with the devices that make up the driving assistance system 10 to perform autonomous driving control of the vehicle. The driving assistance device 20 performs autonomous control of driving operations using devices mounted on the vehicle, and controls the driving operations within a predetermined range. Driving operations that are not controlled by the driving assistance device 20 are manually operated by the driver. When the driver drives the vehicle manually, the driving assistance device 20 does not perform autonomous control of driving operations, and the driving operations of the vehicle are controlled by operation by the driver.

[0020] The driving assistance device 20 is, for example, a computer, and includes a CPU (Central Processing Unit) which is a processor, a ROM (Read Only Memory) in which programs are stored, and a RAM (Random Access Memory) which functions as an accessible storage device. The CPU is an operating circuit that executes the programs stored in the ROM and realizes the functions of the driving assistance device 20. Note that instead of or together with the CPU, an MPU (Micro Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or the like may be used.

[0021] [Functions of the Driving Assistance Device] A program for autonomous driving control of the vehicle is stored in the ROM of the driving assistance device 20, and the autonomous driving control is performed by the CPU of the driving assistance device 20 executing the program. For convenience, Fig. 1 shows a setting unit 21, a determination unit 22, and a control unit 23 as functional blocks for performing autonomous driving control.

[0022] The setting unit 21 recognizes the objects around the vehicle and the driving environment based on the image information acquired from the imaging device 11 and the position information of the objects acquired from the distance measuring device 12. The setting unit 21 also recognizes the driving scene of the vehicle based on the objects around the vehicle and the driving environment, and sets the range used for the determination of the determination unit 22 according to the driving scene.

[0023] The determination unit 22 makes various determinations using the ranges set by the setting unit 21, etc., so that the control unit 23 can drive the vehicle appropriately. The control unit 23 executes autonomous driving control based on the determination results of the determination unit 22, and drives the vehicle. Specifically, the control unit 23 generates a driving route for the vehicle to travel from the current position to the destination, and generates a control signal to be output to the actuator 15 so that the vehicle travels along the generated driving route.

[0024] The functions of the setting unit 21, the determining unit 22, and the control unit 23 will be specifically described below with reference to FIGS. 2A to 2C.

[0025] 2A to 2C are plan views showing an example of a driving scene in which autonomous driving control is performed by the driving assistance system 10 of FIG. 1. In the driving scene shown in FIG. 2A, a first road with two lanes on each side extends in the vertical direction of the drawing, and a second road with two lanes on each side extends in the horizontal direction of the drawing. The intersection of the first road and the second road is an intersection C, and intersection C is provided with crosswalks Z1 and Z3 for pedestrians to cross the first road, and crosswalks Z2 and Z4 for pedestrians to cross the second road. It is assumed that pedestrians do not move on the roads except at crosswalks Z1 to Z4.

[0026] Buildings Y1 to Y4 are located around intersection C shown in FIG. 2A, and sidewalks are located between buildings Y1 to Y4 and roads (first road and second road). Specifically, sidewalk W1 is located between building Y1 and the road, sidewalk W2 is located between building Y2 and the road, sidewalk W3 is located between building Y3 and the road, and sidewalk W4 is located between building Y4 and the road. Pedestrians are free to move along sidewalks W1 to W4. When pedestrians cross a road, they enter the crosswalk from the sidewalk, move along the crosswalk, and exit the crosswalk onto the sidewalk.

[0027] 2A, a vehicle traveling on lane L1 can turn left or go straight at intersection C, and a vehicle traveling on lane L2 can go straight or turn right at intersection C. For example, a vehicle traveling on lane L1 can turn left at intersection C to enter vehicles L3 and L4, or go straight at intersection C to enter lane L5. Similarly, a vehicle traveling on lane L2 can turn right at intersection C to enter vehicles L7 and L8, or go straight at intersection C to enter lane L6.

[0028] A traffic light is installed at intersection C shown in Figure 2A. Traffic lights display traffic signals for controlling traffic to traffic participants such as vehicles, motorcycles, bicycles, and pedestrians using signal lights. Traffic signals include stop signals with red lights and go signals with green lights. Stop signals indicate that pedestrians should not cross the road and that vehicles should not proceed beyond the stopping position. Go signals indicate that pedestrians can proceed and that vehicles can go straight or turn left or right.

[0029] Traffic light TL1 shown in FIG. 2A displays a traffic signal to vehicles traveling on lanes L1 and L2 of a first road. The signal lights of traffic light TL1 are red, yellow, and green, starting from the right side of the vehicle's direction of travel. When the red signal light of traffic light TL1 is lit, traffic light TL1 displays a stop signal to vehicles traveling on lanes L1 and L2. In other words, the vehicle must not enter intersection C beyond the stop position before intersection C (stop line SL1 in the driving scene shown in FIG. 2A ). On the other hand, when the green signal light of traffic light TL1 is lit, traffic light TL1 displays a go signal to vehicles traveling on lanes L1 and L2. In other words, the vehicle can enter intersection C and go straight or turn right or left at intersection C.

[0030] Traffic light TL2 shown in FIG. 2A displays a traffic signal to a pedestrian crossing crosswalk Z2 and moving from sidewalk W1 to sidewalk W2. The signal light of traffic light TL2 is red on the top side and green on the bottom side as seen by a pedestrian entering crosswalk Z2 from sidewalk W1. When the red signal light of traffic light TL2 is lit, traffic light TL2 displays a stop signal to a pedestrian entering crosswalk Z2 from sidewalk W1. In other words, the pedestrian must not cross the second road and must not enter crosswalk Z2. On the other hand, when the green signal light of traffic light TL2 is lit, traffic light TL2 displays a go signal to a pedestrian entering crosswalk Z2 from sidewalk W1. In other words, the pedestrian can cross crosswalk Z2 and cross the second road.

[0031] It is not necessary for intersection C to have a pedestrian traffic light that displays traffic signals to pedestrians. If intersection C does not have a pedestrian traffic light, pedestrians must cross the crosswalk in accordance with the traffic signals displayed by the vehicle traffic light that displays traffic signals to vehicles. Pedestrians also include those who walk on the sidewalk, as well as those who are using wheelchairs or mobility aids, and those who are pushing motorcycles, bicycles, etc.

[0032] Vehicle V1 shown in Figure 2A travels along lane L1 toward the top of the drawing, turns left at intersection C, enters lane L3, and travels to destination X1 ahead on lane L3. In the driving scene shown in Figure 2A, the red signal light on the right side of traffic light TL1 relative to the direction of travel of vehicle V1 traveling along lane L1 is on, so vehicle V1 is stopped at position P1 in front of stop line SL1. Also, pedestrian H1 shown in Figure 2A crosses the second road at crosswalk Z2 and moves from sidewalk W1 to sidewalk W2. In the driving scene shown in Figure 2A, the red signal light on the upper side of traffic light TL2 as seen from pedestrian H1 is on, so pedestrian H1 is stopped at position Q1 on sidewalk W1.

[0033] As part of the autonomous driving control executed by the driving assistance system 10 shown in FIG. 1, the setting unit 21 executes a process of recognizing a driving scene of the vehicle.

[0034] The setting unit 21 determines whether or not an intersection exists ahead in the traveling direction of the vehicle. For example, the setting unit 21 determines whether or not an intersection exists within a predetermined range (for example, a range of 10 to 100 m) ahead of the vehicle based on the current position information of the vehicle acquired by the positioning system and map information acquired from the map database 14.

[0035] If it is determined that there is no intersection ahead in the traveling direction of the vehicle, the control unit 23 causes the vehicle to travel along a traveling route set by a navigation device (not shown). On the other hand, if it is determined that there is an intersection ahead in the traveling direction of the vehicle, the setting unit 21 determines whether the vehicle will turn right or left at the intersection ahead in the traveling direction, based on the traveling route set by the navigation device, etc.

[0036] If it is determined that the vehicle will go straight through the intersection ahead, the control unit 23 causes the vehicle to go straight. On the other hand, if it is determined that the vehicle will turn right or left at the intersection ahead, the setting unit 21 determines whether a crosswalk and a traffic light are installed at the intersection ahead of the vehicle based on the image information acquired from the imaging device 11, the map information acquired from the map database 14, etc.

[0037] If it is determined that at least one of a pedestrian crossing and a traffic light is not installed at the intersection ahead of the vehicle, the control unit 23 executes a normal right turn process or left turn process. On the other hand, if it is determined that a pedestrian crossing and a traffic light are installed at the intersection ahead of the vehicle, the setting unit 21 determines from the image captured by the imaging device 11 whether the traffic light installed at the intersection is displaying a stop signal.

[0038] If it is determined that the traffic light at the intersection is not displaying a stop signal, the control unit 23 executes a normal right turn process or left turn process. On the other hand, if it is determined that the traffic light at the intersection is displaying a stop signal, the setting unit 21 determines whether the vehicle needs to stop before the intersection based on the vehicle speed detected by the vehicle speed sensor and the distance to the intersection.

[0039] If it is determined that the vehicle does not need to (or cannot) stop before the intersection, such as when the vehicle cannot stop before the intersection at a normal deceleration, the control unit 23 allows the vehicle to enter the intersection without stopping. On the other hand, if it is determined that the vehicle needs to stop before the intersection, the control unit 23 stops the vehicle before the intersection.

[0040] When the vehicle stops before an intersection, the setting unit 21 determines whether there is another vehicle (hereinafter also referred to as the other vehicle) ahead of the vehicle that is turning right or left in the same direction as the vehicle's traveling direction. If it is determined that the other vehicle is ahead of the vehicle based on the image information acquired from the imaging device 11 and the position information of the object acquired from the distance measuring device 12, the control unit 23 executes a normal right turn process or left turn process. On the other hand, if it is determined that the other vehicle is not ahead of the vehicle, the intersection passage process of this embodiment is executed.

[0041] In the driving scene shown in Figure 2A, an intersection C is located ahead of vehicle V1 in the direction of travel, and vehicle V1 turns left at intersection C toward destination X1. Furthermore, traffic lights TL1 and TL2 and pedestrian crossings Z1 to Z4 are provided at intersection C, and traffic lights TL1 and TL2 are displaying stop signals. Furthermore, vehicle V1 stops in front of stop line SL1 in response to the stop signal of traffic light TL1, and no other vehicles are stopped ahead of vehicle V1. Therefore, in the driving scene shown in Figure 2A, the intersection passage processing of this embodiment is executed.

[0042] In the intersection passage process of this embodiment, the setting unit 21 sets a detection range for detecting pedestrians who may enter a crosswalk located ahead in the vehicle's direction of travel (hereinafter also referred to as a crosswalk in the direction of travel). A crosswalk in the direction of travel is a crosswalk that the vehicle will pass through when traveling along a set travel route. A crosswalk that pedestrians may enter when the vehicle turns right or left at an intersection (hereinafter also referred to as a target crosswalk) is a crosswalk in the direction of travel that is located in a lane (or road) that the vehicle will enter after exiting the intersection.

[0043] The setting unit 21 sets a detection range at a position on the sidewalk of the road where a pedestrian who may enter the target crosswalk is present. For example, the setting unit 21 sets the detection range at a position on the sidewalk of the road that corresponds to the edge of the target crosswalk. The edge of the crosswalk refers to the part of the crosswalk where a pedestrian enters the crosswalk from the sidewalk (or where a pedestrian exits the crosswalk onto the sidewalk). The shape and size of the detection range can be set as appropriate within a range that allows appropriate detection of a pedestrian who may enter the crosswalk from the sidewalk.

[0044] The setting unit 21 sets the detection range at a position corresponding to at least one of the two (or multiple) ends of the target crosswalk that is closer to the lane into which a vehicle exiting the intersection will enter. When the vehicle turns left at the intersection, the setting unit 21 sets a detection range for detecting pedestrians who may enter the crosswalk located to the left front of the vehicle, and when the vehicle turns right at the intersection, the setting unit 21 sets a detection range for detecting pedestrians who may enter the crosswalk located to the right front of the vehicle.

[0045] 2A , the setting unit 21 sets a detection range A1 on the sidewalk W1. The position where the detection range A1 is set corresponds to one of two ends E1, E2 of the crosswalk Z2, which is closer to the lane L3 into which the vehicle V1 is entering after exiting the intersection C. The detection range A1 includes a pedestrian H1 who is stopped on the sidewalk W1 in front of the crosswalk Z2 and is waiting for the traffic light TL2 to change from a stop signal to a proceed signal.

[0046] The determination unit 22 determines whether or not a pedestrian is present within the detection range set by the setting unit 21, based on the image information acquired from the imaging device 11 and the position information of the target object acquired from the distance measuring device 12. If it is determined that a pedestrian is not present within the detection range, the control unit 23 executes a normal right turn process or left turn process. On the other hand, if it is determined that a pedestrian is present within the detection range, the determination unit 22 determines whether or not the stop signal displayed by the traffic light has switched to a proceed signal, based on the image information acquired from the imaging device 11.

[0047] If it is determined that the traffic light is displaying a stop signal (the stop signal display is maintained), the determination unit 22 repeats the determination process until the traffic light displays a go signal. On the other hand, if it is determined that the stop signal displayed by the traffic light has switched to a go signal, the control unit 23 maintains the vehicle's stopped state for a predetermined time after the go signal is displayed. The predetermined time can be set appropriately within a range that does not cause pedestrians to hesitate to enter the crosswalk when the vehicle starts moving, and is, for example, the time required for a pedestrian present within the detection range to enter the crosswalk in the direction of travel (specifically, 10 seconds to 2 minutes).

[0048] 2A , the determination unit 22 determines that a pedestrian H1 is present within the detection range A1. In addition, the determination unit 22 determines whether the stop signal displayed by the traffic light TL1 (or both the traffic light TL1 and the traffic light TL2) has switched to a proceed signal. That is, the determination unit 22 determines at least whether the stop signal displayed by the traffic light for vehicles has switched to a proceed signal.

[0049] 2B is a plan view showing a driving scene in which the stop signals of traffic lights TL1 and TL2 change to go signals in the driving scene shown in FIG. 2A. When the stop signals of traffic lights TL1 and TL2 change to go signals as in the driving scene shown in FIG. 2B, the determination unit 22 determines that the stop signals displayed by traffic lights TL1 and TL2 have changed to go signals, and the control unit 23 continues to stop the vehicle V1 at position P1 for a predetermined time. Furthermore, if the vehicle V1 remains stopped for a predetermined time after the go signal is displayed by traffic light TL1 (or both traffic lights TL1 and TL2), the control unit 23 may start the vehicle V1 after the predetermined time has elapsed.

[0050] When starting the vehicle V1 after a predetermined time has elapsed, the control unit 23 causes the vehicle V1 to travel from position P1 to position P2 just before the crosswalk Z2 along the travel trajectory T1 shown in FIG. 2B and stop the vehicle V1 at position P2. The acceleration of the vehicle V1 when traveling to position P2 is set to, for example, a predetermined acceleration described below. After the vehicle V1 stops at position P2, the determination unit 22 determines, based on the image information acquired from the imaging device 11 and the position information of the object acquired from the distance measuring device 12, whether the pedestrian H1 has passed in front of the vehicle V1 and whether the vehicle V1 can pass through the crosswalk Z2 without coming into contact with the pedestrian H1.

[0051] If pedestrian H1 is not passing in front of vehicle V1 and it is determined that vehicle V1 cannot pass through crosswalk Z2 without coming into contact with pedestrian H1, control unit 23 maintains vehicle V1 in a stopped state at position P2. On the other hand, as shown in Fig. 2B , if pedestrian H1 crosses crosswalk Z2 and moves from position Q1 to position Q2, control unit 23 determines that vehicle V1 can pass through crosswalk Z2 without coming into contact with pedestrian H1. In this case, control unit 23 releases the brakes on vehicle V1, starts vehicle V1, and causes vehicle V1 to travel from position P2 to position P3 along travel path T2 shown in Fig. 2C .

[0052] Alternatively, when it is determined that the stop signal displayed by the traffic light has changed to a go signal, the control unit 23 may start the vehicle before a predetermined time has elapsed since the go signal was displayed, and cause the vehicle to travel to a target stopping position in front of the crosswalk at a predetermined acceleration. The predetermined acceleration can be set to an appropriate value within a range that does not cause pedestrians to hesitate to enter the crosswalk when the vehicle approaches the crosswalk, and is, for example, an acceleration lower than the acceleration set when there are no pedestrians crossing the crosswalk in the direction of travel (or the normal acceleration set in autonomous driving control).

[0053] The target stopping position can be set as an appropriate position within a range where the vehicle can avoid contact with pedestrians crossing the crosswalk, for example, a position a predetermined distance in front of the crosswalk in the direction of travel. The predetermined distance is a distance that can avoid contact between the pedestrian and the vehicle if the pedestrian crossing the crosswalk falls toward the vehicle, for example, 2 to 4 meters.

[0054] For example, in the driving scene shown in Fig. 2B , if it is determined that pedestrian H1 has entered crosswalk Z2, the control unit 23 starts the vehicle V1 before a predetermined time has elapsed since traffic lights TL1 and TL2 displayed a proceed signal, and causes the vehicle V1 to travel from position P1 to position P2 along a travel trajectory T1. After the vehicle V1 stops at position P2, which is the target stop position, the determination unit 22 determines whether the pedestrian H1 has passed in front of the vehicle V1 and whether the vehicle V1 can pass through the crosswalk Z2 without coming into contact with the pedestrian H1. If it is determined that the vehicle V1 can pass through the crosswalk Z2 without coming into contact with the pedestrian H1, the control unit 23 starts the vehicle V1 and causes the vehicle V1 to travel from position P2 to position P3 along the travel trajectory T2 shown in Fig. 2C .

[0055] If a pedestrian is present within the detection range, the setting unit 21 may set a determination range corresponding to the field of view of the pedestrian facing the direction of the target crosswalk, and the determination unit 22 may calculate a first distance between the vehicle and the determination range. If the first distance is less than a first predetermined distance, the control unit 23 releases the brakes of the vehicle before a predetermined time has elapsed since the display of the proceed signal, and stops the vehicle before the vehicle speed reaches or exceeds a predetermined speed. On the other hand, if the first distance is equal to or greater than the first predetermined distance, the control unit 23 starts the vehicle before the predetermined time has elapsed since the display of the proceed signal, and drives the vehicle to a target stopping position where the first distance becomes less than the first predetermined distance.

[0056] The determination range does not necessarily have to coincide with the pedestrian's field of vision, but it is sufficient that it includes at least the pedestrian's horizontal field of vision (or horizontal effective field of vision). The determination range may also be a range that is a certain distance from the pedestrian (for example, a range defined by an arc centered on the pedestrian). The first predetermined distance can be set to an appropriate value within a range in which the approach of a vehicle to a pedestrian does not cause the pedestrian to hesitate to enter the crosswalk, for example, 0.5 to 2 m. The predetermined vehicle speed is a vehicle speed (i.e., a slow speed) that allows the vehicle to stop immediately, for example, faster than 0 km / h and equal to or less than 5 km / h.

[0057] The driving scene shown in FIG. 3A is the same as the driving scene shown in FIG. 2A , except that vehicle V2 is traveling in lane L2 and pedestrian H2 is present on sidewalk W3. Vehicle V2 shown in FIG. 3A is equipped with the driving assistance system 10 shown in FIG. 1 , just like vehicle V1. That is, the intersection passage process of this embodiment is executed in vehicles V1 and V2. Furthermore, vehicle V2 travels toward the top of lane L2, turns right at intersection C, enters lane L7, and travels to destination X2 located ahead on lane L7. In the driving scene shown in FIG. 3A , traffic light TL1 is displaying a stop signal, so vehicle V2 is stopped at position P4 just before stop line SL1.

[0058] Pedestrian H2 shown in Fig. 3A crosses the second road at crosswalk Z4 and moves from sidewalk W3 to sidewalk W4. Traffic light TL3 shown in Fig. 3A displays a traffic signal to the pedestrian who crosses crosswalk Z4 and moves from sidewalk W3 to sidewalk W4. In the driving scene shown in Fig. 3A, the red signal light of traffic light TL2, which is on the upper side as seen from pedestrian H2, is lit, so pedestrian H2 is stopped at position Q3 on sidewalk W3.

[0059] 3A , a pedestrian H1 is present within the detection range A1, so the setting unit 21 sets a determination range B1 that corresponds to the field of view of the pedestrian H1 facing the direction of the crosswalk Z2. The determination unit 22 calculates a distance D1 (first distance) between the vehicle V1 and the determination range B1 based on the position information of the pedestrian H1 acquired from the distance measuring device 12, and determines whether the distance D1 is less than a first predetermined distance.

[0060] If it is determined that the distance D1 shown in Fig. 3A is less than the first predetermined distance, the control unit 23 releases the brakes on the vehicle V1 before a predetermined time has elapsed since the display of the proceed signal by the traffic lights TL1 and TL2, as shown in Fig. 3B, and causes the vehicle V1 to proceed straight along the travel path T3. At this time, the acceleration of the vehicle V1 is set to a predetermined acceleration. If the vehicle V1 accelerates at the predetermined acceleration and the vehicle speed of the vehicle V1 reaches the predetermined vehicle speed at position P5, the control unit 23 stops the vehicle V1 at position P5. This can indicate to the pedestrian H1 the intention to keep the vehicle V1 stopped until the pedestrian H1 crosses the crosswalk Z2.

[0061] In the driving scene shown in Fig. 3A , a detection range A2 is set on the sidewalk W3. The position at which the detection range A2 is set corresponds to one of two ends E3, E4 (shown in Fig. 3B ) of the crosswalk Z4, which is closer to the lane L7 into which the vehicle V2 will enter after turning right at the intersection C. Because a pedestrian H2 is present within the detection range A2, the setting unit 21 sets a determination range B2 that corresponds to the field of view of the pedestrian H2 facing the direction of the crosswalk Z4. The determination unit 22 calculates a distance D2 (first distance) between the vehicle V2 and the determination range B2 and determines whether the distance D2 is less than a first predetermined distance.

[0062] If it is determined that the distance D2 shown in Fig. 3A is equal to or greater than the first predetermined distance, the control unit 23 releases the brakes on the vehicle V2 before a predetermined time has elapsed since the display of the proceed signal by the traffic light TL1, and causes the vehicle V1 to travel along the travel path T4 from position P4 to position P6, as shown in Fig. 3B. Then, the control unit 23 stops the vehicle V2 at position P6, which is the target stop position.

[0063] When the determination range is set by the setting unit 21, the determination unit 22 may determine whether the vehicle is within the determination range. If it is determined that the vehicle is within the determination range, the control unit 23 releases the brakes of the vehicle before a predetermined time has elapsed since the display of the proceeding signal, and stops the vehicle before the vehicle speed reaches or exceeds a predetermined vehicle speed. On the other hand, if it is determined that the vehicle is not within the determination range, the control unit 23 controls the driving operation of the vehicle depending on whether the first distance is less than the first predetermined distance or greater than or equal to the first predetermined distance, as described above.

[0064] For example, in the driving scene shown in FIG. 3A , a range including vehicle V1 is set as the determination range corresponding to the field of view of pedestrian H1 facing the crosswalk Z2. In this case, the determination unit 22 determines whether vehicle V1 is included in the determination range based on, for example, current position information of vehicle V1 acquired by the positioning system. Since vehicle V1 is included in the determination range, the control unit 23 releases the brakes on vehicle V1 before a predetermined time has elapsed since the proceeding signals were displayed by traffic lights TL1 and TL2, as shown in FIG. 3B , and causes vehicle V1 to proceed straight along travel path T3. At this time, the acceleration of vehicle V1 may be set to a predetermined acceleration. The control unit 23 stops vehicle V1 before the vehicle speed of vehicle V1 reaches or exceeds the predetermined vehicle speed.

[0065] When setting the detection range, the setting unit 21 may detect the width of the road on which the target pedestrian crossing is located based on the position information of the object obtained from the distance measuring device 12, the map information obtained from the map database 14, and the like. If the detected width is less than the predetermined width, the setting unit 21 sets a detection range on the sidewalk of the road corresponding to both ends of the target pedestrian crossing. On the other hand, if the detected width is equal to or greater than the predetermined width, the setting unit 21 sets a detection range on the sidewalk of the road corresponding to the end of the target pedestrian crossing that is closer to the lane into which the vehicle will enter after turning right or left. The predetermined width can be set to an appropriate value within a range that allows appropriate detection of pedestrians who hesitate to enter the crosswalk due to the start of a vehicle, such as a width corresponding to a road with two lanes on each side (specifically, 15 to 30 meters).

[0066] For example, assume that the width of the second road shown in FIG. 3A is equal to or greater than a predetermined width. In this case, the setting unit 21 detects the width K1 of the second road on which the crosswalk Z2 is provided based on the position information of the shoulders of the lanes L3 and L4 acquired from the distance measuring device 12. Because the width K1 of the second road shown in FIG. 3A is equal to or greater than the predetermined width, the setting unit 21 sets, on the sidewalk W1, a detection range A1 corresponding to the end E1 of the ends E1 and E2 of the crosswalk Z2 that is closer to the lane L3 into which the vehicle V1 will enter after turning left at the intersection C. Alternatively, the setting unit 21 detects the width K1a of the second road on which the crosswalk Z4 is provided. Because the width K1a shown in FIG. 3A is equal to or greater than the predetermined width, the setting unit 21 sets, on the sidewalk W3, a detection range A2 corresponding to the end E3 of the ends E3 and E4 of the crosswalk Z4 that is closer to the lane L7 into which the vehicle V2 will enter after turning right at the intersection C.

[0067] On the other hand, Figure 4 is a plan view showing an example of a driving scene in which the width of the road on which the target crosswalk is located is less than a predetermined width. In the driving scene shown in Figure 4, a third road with one lane in each direction extends in the vertical direction of the drawing, and a fourth road with one lane in each direction extends in the horizontal direction of the drawing. The intersection of the third road and the fourth road is intersection Ca, and intersection Ca is provided with crosswalks Z1a and Z3a for pedestrians to cross the third road, and crosswalks Z2a and Z4a for pedestrians to cross the fourth road.

[0068] 4, buildings Y1a to Y4a exist around intersection Ca, and sidewalks are located between buildings Y1a to Y4a and the road. Specifically, sidewalk W1a is located between building Y1a and the road, sidewalk W2a is located between building Y2a and the road, sidewalk W3a is located between building Y3a and the road, and sidewalk W4a is located between building Y4a and the road.

[0069] Vehicles traveling in lane L1a shown in Fig. 4 can turn left, right, or go straight at intersection Ca. Traffic light TL1a shown in Fig. 4 displays a traffic signal for vehicles traveling in lane L1a, and traffic light TL2a displays a traffic signal for pedestrians crossing crosswalk Z2a and moving from sidewalk W1a to sidewalk W2a. The arrangement of the signal lights of traffic lights TL1a and TL2a is the same as that of traffic lights TL1 and TL2 shown in Fig. 2A.

[0070] A vehicle V1 shown in Fig. 4 travels in lane L1a toward the top of the drawing, turns left at intersection Ca, enters lane L3a, and travels to destination X1a ahead on lane L3a. In the driving scene shown in Fig. 4, traffic light TL1a is displaying a stop signal, so vehicle V1 is stopped at position P1a in front of stop line SL1a. Also, a pedestrian H1 shown in Fig. 4 crosses the second road at crosswalk Z2a and moves from sidewalk W1a to sidewalk W2a. In the driving scene shown in Fig. 4, pedestrian H1 stops at position Q1a on sidewalk W1a in response to the stop signal displayed by traffic light TL2a.

[0071] In the driving scene shown in Fig. 4, the setting unit 21 detects the width K2 of the fourth road on which the target crosswalk Z2a is located, from road width information obtained from the map database 14. Because the width K2 of the fourth road shown in Fig. 4 is less than the predetermined width, the setting unit 21 sets detection ranges A1a and A3 corresponding to both ends of the crosswalk Z2a for each of the sidewalks W1a and W2a.

[0072] The determination unit 22 may detect a second distance between the vehicle and one of the ends of the target crosswalk that is closer to the lane into which the vehicle will enter after turning right or left, based on the position information of the object obtained from the distance measuring device 12, and determine whether the second distance is less than a second predetermined distance. The second predetermined distance can be set to an appropriate value within a range that does not cause pedestrians to hesitate to enter the crosswalk when a vehicle approaches them, and may be, for example, 1 to 4 m.

[0073] If the control unit 23 determines that the second distance is less than the second predetermined distance, the control unit 23 maintains the vehicle stopped for a predetermined time, whereas if the control unit 23 determines that the second distance is equal to or greater than the second predetermined distance, the control unit 23 starts the vehicle before the predetermined time has elapsed since the display of the proceed signal, and causes the vehicle to travel to the target stopping position at a predetermined acceleration.

[0074] 2A , the determination unit 22 detects the distance D3 (second distance) between the vehicle V1 and one of the ends E1 and E2 of the crosswalk Z2, which is closer to the lane L3 into which the vehicle V1 will enter after turning left at the intersection C, based on the position information of the shoulder of the lane L3 acquired from the distance measurement device 12. If the distance D3 is less than the second predetermined distance, the control unit 23 keeps the vehicle V1 stopped at the position P1 for a predetermined time.

[0075] The determination unit 22 may detect a third distance between the vehicle and a pedestrian present within the detection range based on the position information of the object acquired from the distance measuring device 12, and determine whether the third distance is less than a third predetermined distance. The third predetermined distance can be set to an appropriate value within a range that does not cause the pedestrian to hesitate to enter the crosswalk when the vehicle approaches the pedestrian, and may be, for example, 1 to 4 m.

[0076] If the control unit 23 determines that the third distance is less than the third predetermined distance, the control unit 23 maintains the vehicle stopped for a predetermined time. On the other hand, if the control unit 23 determines that the third distance is equal to or greater than the third predetermined distance, the control unit 23 starts the vehicle before the predetermined time has elapsed since the display of the proceed signal, and causes the vehicle to travel to the target stopping position at a predetermined acceleration.

[0077] 3A , the determination unit 22 detects a distance D4 (third distance) between the vehicle V1 and the pedestrian H1 on the crosswalk Z2 based on the position information of the pedestrian H1 acquired from the distance measuring device 12. If the distance D4 is less than the third predetermined distance, the control unit 23 keeps the vehicle V1 stopped at the position P1 for a predetermined time.

[0078] The determination unit 22 may calculate a fourth distance required for the vehicle to travel to the target crosswalk based on map information obtained from the map database 14, and determine whether the fourth distance is less than a fourth predetermined distance. The fourth predetermined distance can be set to an appropriate value within a range that does not cause pedestrians to hesitate to enter the target crosswalk when the vehicle approaches the crosswalk, for example, 5 to 20 meters.

[0079] If the control unit 23 determines that the fourth distance is less than the fourth predetermined distance, the control unit 23 maintains the vehicle stopped for a predetermined time. On the other hand, if the control unit 23 determines that the fourth distance is equal to or greater than the fourth predetermined distance, the control unit 23 starts the vehicle before the predetermined time has elapsed since the display of the proceed signal, and causes the vehicle to travel to the target stopping position at a predetermined acceleration.

[0080] 3A , the determination unit 22 calculates a fourth distance required for the vehicle V2 to travel from the current position P4 to the crosswalk Z4, based on the current position information of the vehicle V2 acquired by the positioning system and the map information acquired from the map database 14. If the fourth distance is equal to or greater than a fourth predetermined distance, the control unit 23 causes the vehicle V2 to travel from the position P4 to a position P6 along the travel trajectory T6 shown in FIG.

[0081] The determination unit 22 may determine whether a pedestrian present within the detection range has entered the crosswalk before a predetermined time has elapsed since the display of the proceed signal, based on the image information acquired from the imaging device 11 and the position information of the object acquired from the distance measuring device 12. If it is determined that a pedestrian present within the detection range has entered the crosswalk, the control unit 23 releases the brakes of the vehicle before the predetermined time has elapsed since the display of the proceed signal, and causes the vehicle to travel to a target stopping position at a predetermined acceleration. On the other hand, if it is determined that a pedestrian present within the detection range has not entered the crosswalk, the control unit 23 maintains the stopped state of the vehicle, for example, until the predetermined time has elapsed since the display of the proceed signal.

[0082] 2B , the determination unit 22 determines, from the image information acquired from the imaging device 11, whether or not a pedestrian H1 in the detection range A1 entered the crosswalk Z2 before a predetermined time has elapsed since the display of a proceed signal by traffic lights TL1 and TL2. If it is determined that the pedestrian H1 has entered the crosswalk Z2, the control unit 23 immediately releases the brakes on the vehicle V1 and causes the vehicle V1 to travel at a predetermined acceleration to a position P2, which is a target stopping position.

[0083] The determination unit 22 may determine whether or not a stop line (hereinafter also referred to as an intra-intersection stop line) exists within the intersection and in front of the target crosswalk, based on the image information acquired from the imaging device 11. If an intra-intersection stop line is detected and it is determined that an intra-intersection stop line exists, the control unit 23 sets the position of the intra-intersection stop line as the target stop position. On the other hand, if an intra-intersection stop line is not detected and it is determined that an intra-intersection stop line does not exist, the control unit 23 sets a position a predetermined distance in front of the target crosswalk as the target stop position.

[0084] The driving scene shown in Figure 5 is similar to the driving scene shown in Figure 3B except that a stop line SL2 is provided as an intra-intersection stop line at intersection C. However, vehicle V1 and pedestrian H1 are not shown in Figure 5.

[0085] In the driving scene shown in Fig. 5, the determination unit 22 detects the stop line SL2 from the image information acquired from the imaging device 11 and determines that there is a stop line in the intersection. The control unit 23 sets the position of the stop line SL2 as the target stopping position and causes the vehicle V2 to travel from position P4 to position P7 just before the stop line SL2 along the driving trajectory T5 shown in Fig. 5.

[0086] 6 and 7A to 7C, a procedure for processing information by the driving assistance device 20 will be described. The processing described below is executed at predetermined time intervals (for example, every 0.1 to 1 millisecond) by a processor (CPU) included in the driving assistance device 20.

[0087] FIG. 6 is a flowchart showing an example of a processing procedure executed in the driving assistance system 10.

[0088] First, in step S1, the driving assistance device 20 determines whether or not an intersection exists ahead in the traveling direction of the vehicle. If it is determined that no intersection exists ahead in the traveling direction of the vehicle, the process proceeds to step S8, where the driving assistance device 20 executes normal autonomous driving control, and then the process proceeds to step S9. On the other hand, if it is determined that an intersection exists ahead in the traveling direction of the vehicle, the process proceeds to step S2.

[0089] In step S2, the driving assistance device 20 determines whether the vehicle will turn right or left at an intersection ahead in the traveling direction. If it is determined that the vehicle will not turn right or left at the intersection ahead (i.e., will go straight), the process proceeds to step S8. On the other hand, if it is determined that the vehicle will turn right or left at the intersection ahead, the process proceeds to step S3.

[0090] In step S3, the driving assistance device 20 determines whether or not a crosswalk and a traffic light are installed at the intersection ahead of the vehicle. If it is determined that at least one of a crosswalk and a traffic light is not installed at the intersection ahead of the vehicle, the process proceeds to step S8. On the other hand, if it is determined that a crosswalk and a traffic light are installed at the intersection ahead of the vehicle, the process proceeds to step S4.

[0091] In step S4, it is determined whether the traffic light at the intersection is displaying a stop signal. If it is determined that the traffic light at the intersection is not displaying a stop signal, the process proceeds to step S8. On the other hand, if it is determined that the traffic light at the intersection is displaying a stop signal, the process proceeds to step S5.

[0092] In step S5, the driving assistance device 20 determines whether the vehicle needs to stop before the intersection. If it is determined that the vehicle does not need to stop before the intersection, the process proceeds to step S8. On the other hand, if it is determined that the vehicle needs to stop before the intersection, the process proceeds to step S6.

[0093] In step S6, the driving assistance device 20 determines whether or not the other vehicle is present ahead of the vehicle. If it is determined that the other vehicle is present ahead of the vehicle, the process proceeds to step S8. On the other hand, if it is determined that the other vehicle is not present ahead of the vehicle, the process proceeds to step S7.

[0094] In step S7, the driving assistance device 20 executes the intersection passage process of this embodiment, and then proceeds to step S9. In step S9, the driving assistance device 20 determines whether the vehicle has arrived at the destination. If it is determined that the vehicle has not arrived at the destination, the process proceeds to step S1. On the other hand, if it is determined that the vehicle has arrived at the destination, the execution of the routine ends.

[0095] Next, Figures 7A to 7C are flowcharts showing an example of a subroutine of step S7 in Figure 6. It is assumed that, when the process shown in Figure 7A is started, the vehicle is stopped in front of an intersection and the traffic light at the intersection is displaying a stop signal.

[0096] 7A, the driving assistance device 20 sets a detection range for detecting pedestrians who may enter the target crosswalk, and then determines whether a pedestrian is present in the detection range in step S12. If a pedestrian is not detected in the detection range and it is determined that no pedestrian is present in the detection range, the process proceeds to step S15, where the vehicle passes through the intersection using normal autonomous driving control. On the other hand, if a pedestrian is detected in the detection range and it is determined that a pedestrian is present in the detection range, the process proceeds to step S13.

[0097] In step S13, the driving assistance device 20 calculates a second distance between the vehicle and one of the ends of the target crosswalk that is closer to the lane into which the vehicle will enter after turning right or left, and then in the subsequent step S14, determines whether the second distance is less than the second distance. If it is determined that the second distance is less than the second distance, the process proceeds to step S21 in Fig. 7B. On the other hand, if it is determined that the second distance is equal to or greater than the second distance, the process proceeds to step S31 in Fig. 7C.

[0098] 7B, the driving assistance device 20 determines whether the traffic light at the intersection is displaying a go signal. If it is determined that the traffic light at the intersection is displaying a stop signal but not a go signal, the process proceeds to step S22, where the driving assistance device 20 maintains the vehicle stopped. On the other hand, if it is determined that the stop signal has switched to a go signal and the traffic light at the intersection is displaying a go signal, the process proceeds to step S23.

[0099] In step S23, the driving assistance device 20 maintains the vehicle in a stopped state and starts measuring the elapsed time from when the proceed signal started to be displayed, and then in step S24, determines whether a predetermined time has elapsed from when the proceed signal started to be displayed. If it is determined that the predetermined time has not elapsed from when the proceed signal started to be displayed, the driving assistance device 20 proceeds to step S25, where it determines whether a pedestrian within the detection range has started to cross the road.

[0100] If it is determined that a pedestrian within the detection range has started crossing the road, the process proceeds to step S26, and the driving support device 20 starts the vehicle. On the other hand, if it is determined that a pedestrian within the detection range has not started crossing the road, the process proceeds to step S24. If it is determined in step S24 that a predetermined time has elapsed since the start of the display of the proceed signal, the process proceeds to step S26.

[0101] 7C, the driving assistance device 20 determines whether the traffic light at the intersection is displaying a go signal. If it is determined that the traffic light at the intersection is displaying a stop signal but not a go signal, the process proceeds to step S32, where the driving assistance device 20 maintains the vehicle's stopped state. On the other hand, if it is determined that the stop signal has switched to a go signal and the traffic light at the intersection is displaying a go signal, the process proceeds to step S33.

[0102] In step S33, the driving assistance device 20 starts the vehicle and stops it at the target stopping position, and then in the following step S34, determines whether or not the pedestrian within the detection range has completed crossing the road. If it is determined that the pedestrian within the detection range has not completed crossing the road, the driving assistance device 20 repeats step S34. On the other hand, if it is determined that the pedestrian within the detection range has completed crossing the road, the driving assistance device 20 proceeds to step S35, where it starts the vehicle.

[0103] According to the present embodiment, there is provided a driving assistance method executed by a driving assistance device (20) that autonomously controls vehicle driving, in which, when the vehicle is turning right or left at an intersection equipped with a traffic light and a crosswalk, the driving assistance device (20) stops the vehicle before the intersection in response to a stop signal displayed by the traffic light, and when there is no vehicle ahead of the vehicle turning right or left in the same direction as the vehicle's direction of travel, sets a detection range for detecting pedestrians who may enter the crosswalk in the vehicle's direction of travel, and when the pedestrian is present within the detection range and the stop signal displayed by the traffic light changes to a go signal, the driving assistance device (20) maintains the vehicle stopped for a predetermined time after the go signal is displayed, or starts the vehicle before the predetermined time has elapsed after the go signal is displayed, and drives the vehicle at a predetermined acceleration to a target stopping position in front of the crosswalk. This prevents pedestrians from hesitating to enter the crosswalk. Furthermore, it is possible to prevent changes in pedestrian behavior.

[0104] In the driving assistance method and driving assistance device 20 of this embodiment, if the pedestrian is present within the detection range, a determination range is set that corresponds to the field of view of the pedestrian facing the direction of the crosswalk where the pedestrian can enter, and it is determined whether the vehicle is within the determination range. If it is determined that the vehicle is within the determination range, the brakes of the vehicle are released before the predetermined time has elapsed since the display of the proceed signal, and the vehicle is stopped before the vehicle speed reaches or exceeds a predetermined speed. This makes it possible to notify pedestrians that the vehicle will not move even if the traffic signal changes.

[0105] In the driving assistance method and driving assistance device 20 of this embodiment, if the pedestrian is present within the detection range, a determination range corresponding to the field of view of the pedestrian facing the direction of the crosswalk where the pedestrian can enter is set, a first distance between the vehicle and the determination range is calculated, and if the first distance is less than a first predetermined distance, the brakes of the vehicle are released before the predetermined time has elapsed since the display of the proceed signal and the vehicle is stopped before the vehicle speed of the vehicle reaches or exceeds a predetermined vehicle speed, and if the first distance is equal to or greater than the first predetermined distance, the vehicle is started before the predetermined time has elapsed since the display of the proceed signal and the vehicle is driven to the target stopping position where the first distance becomes less than the first predetermined distance. This makes it possible to indicate to following vehicles that the pedestrian is waiting to pass and to prevent the pedestrian's behavior from changing.

[0106] In the driving assistance method and driving assistance device 20 of this embodiment, when setting the detection range, the width of the road on which the crosswalk that the pedestrian can enter is detected. If the width is less than a predetermined width, the detection range is set on the sidewalk of the road corresponding to both ends of the crosswalk that the pedestrian can enter. If the width is equal to or greater than the predetermined width, the detection range is set on the sidewalk corresponding to the end of the crosswalk that the pedestrian can enter, which is closer to the lane into which the vehicle will enter after turning right or left. This narrows the detection range. Furthermore, by excluding pedestrians far from the vehicle's right-turn or left-turn path, it is possible to appropriately detect only pedestrians that the vehicle may affect, thereby reducing the occurrence of unnecessary driving behavior.

[0107] In the driving assistance method and driving assistance device 20 of this embodiment, a second distance is detected between the vehicle and one of the ends of the crosswalk where the pedestrian can enter, which is closer to the lane the vehicle will enter after turning right or left, and if the second distance is less than a second predetermined distance, the stopped state of the vehicle is maintained for the predetermined time, and if the second distance is equal to or greater than the second predetermined distance, the vehicle is started before the predetermined time has elapsed since the display of the proceed signal, and is caused to travel to the target stopping position at the predetermined acceleration. As a result, when the stop line and the intersection are far apart, a control method is selected taking into account the relative positions of the crosswalk and the vehicle, etc., and driving that takes pedestrians and following vehicles into consideration can be achieved.

[0108] In the driving assistance method and driving assistance device 20 of this embodiment, the driving assistance device detects a third distance between the vehicle and the pedestrian present within the detection range, and if the third distance is less than a third predetermined distance, maintains the stopped state of the vehicle for the predetermined time, and if the third distance is equal to or greater than the third predetermined distance, starts the vehicle before the predetermined time has elapsed since the display of the proceed signal, and causes the vehicle to travel to the target stopping position at the predetermined acceleration. As a result, when the stop line and the intersection are far apart, a control method is selected taking into consideration the positional relationship between the crosswalk and the vehicle, etc., and driving that takes pedestrians and following vehicles into consideration can be achieved.

[0109] In the driving assistance method and driving assistance device 20 of this embodiment, a fourth distance required for the vehicle to travel to the crosswalk where the pedestrian can enter is calculated, and if the fourth distance is less than a fourth predetermined distance, the stopped state of the vehicle is maintained for the predetermined time, and if the fourth distance is equal to or greater than the fourth predetermined distance, the vehicle is started before the predetermined time has elapsed since the display of the proceed signal, and is caused to travel to the target stopping position at the predetermined acceleration. As a result, when the stop line and the intersection are far apart, a control method is selected taking into consideration the positional relationship between the crosswalk and the vehicle, etc., and driving that takes pedestrians and following vehicles into consideration can be achieved.

[0110] In the driving assistance method and driving assistance device 20 of this embodiment, if the vehicle remains stopped for the predetermined time after the display of the proceed signal, the vehicle is started after the predetermined time has elapsed. If the pedestrian present within the detection range enters the crosswalk before the predetermined time has elapsed after the display of the proceed signal, the vehicle's brakes are released before the predetermined time has elapsed after the display of the proceed signal, and the vehicle is allowed to travel to the target stopping position at the predetermined acceleration. This prevents the vehicle from being stopped unnecessarily. Furthermore, if the pedestrian begins to cross the road, the pedestrian can pass through the crosswalk without stopping.

[0111] In the driving assistance method and driving assistance device 20 of this embodiment, the predetermined time is set to the time required for the pedestrian present within the detection range to enter the crosswalk in the traveling direction, thereby making it possible to prevent the pedestrian from obstructing the passage of following vehicles.

[0112] In the driving assistance method and driving assistance device 20 of this embodiment, the predetermined acceleration is set to an acceleration lower than the acceleration that is set when there is no pedestrian crossing the crosswalk in the traveling direction, thereby making it possible to further prevent pedestrians who are about to cross the crosswalk from hesitating to enter the crosswalk.

[0113] In the driving assistance method and driving assistance device 20 of this embodiment, if a stop line is present within the intersection and before the crosswalk where the pedestrian can enter, the position of the stop line is set as the target stopping position, and if no stop line is present, a position a predetermined distance in front of the crosswalk where the pedestrian can enter is set as the target stopping position. This allows the vehicle to pass through the target crosswalk smoothly.

[0114] 10...cruising assistance system, 11...imaging device, 12...distance measuring device, 13...on-board sensor, 14...map database, 15...actuator, 20...cruising assistance device, 21...setting unit, 22...determination unit, 23...control unit, A1, A1a, A2, A3...detection range, B1, B2...determination range, C, Ca...intersection, D1, D2, D3, D4...distance, E1, E2...edge, H1, H2...pedestrian, K1, K2...width, L1, L1a, L2, L3, L3a, L4, L5, L5a, L6, L7, L7a, L8...lane, P1, P1a, P 2, P3, P4, P5, P6, P7...vehicle position, Q1, Q1a, Q2, Q3...pedestrian position, SL1, SL1a, SL2...stop line, T1, T2, T3, T4, T5...driving trajectory, TL1, TL1a, TL2, TL2a, TL3...traffic light, V1, V2...vehicle, W1, W1a, W2, W2a, W3, W3a, W4, W4a...sidewalk, X1, X1a, X2...destination, Y1, Y1a, Y2, Y2a, Y3, Y3a, Y4, Y4a...building, Z1, Z1a, Z2, Z2a, Z3, Z3a, Z4, Z4a...crosswalk

Claims

1. A driving assistance method executed by a driving assistance device that autonomously controls vehicle driving, wherein, when the vehicle is turning right or left at an intersection equipped with traffic lights and a crosswalk, the driving assistance device stops the vehicle before the intersection in response to a stop signal displayed by the traffic light, and, when there is no other vehicle ahead of the vehicle turning right or left in the same direction as the vehicle's direction of travel, sets a detection range for detecting pedestrians who may enter the crosswalk in the vehicle's direction of travel, and, when the pedestrian is present within the detection range and the stop signal displayed by the traffic light changes to a go signal, maintains the vehicle's stopped state for a predetermined time after the go signal is displayed, or starts the vehicle before the predetermined time has elapsed after the go signal is displayed, and drives the vehicle at a predetermined acceleration to a target stopping position in front of the crosswalk.

2. The driving assistance method according to claim 1, wherein, when the pedestrian is present within the detection range, the driving assistance device sets a judgment range corresponding to the field of view of the pedestrian facing the direction of the crosswalk into which the pedestrian can enter, judges whether the vehicle is within the judgment range, and, if it is determined that the vehicle is within the judgment range, releases the brakes of the vehicle before the predetermined time has elapsed since the proceed signal was displayed, and stops the vehicle before its speed reaches or exceeds a predetermined speed.

3. The driving assistance method according to claim 1 or 2, wherein the driving assistance device, when the pedestrian is present within the detection range, sets a judgment range corresponding to the field of view of the pedestrian facing the direction of the crosswalk into which the pedestrian can enter; calculates a first distance between the vehicle and the judgment range; when the first distance is less than a first predetermined distance, releases the brakes of the vehicle before the predetermined time has elapsed since the display of the proceed signal and stops the vehicle before the vehicle speed of the vehicle reaches or exceeds a predetermined vehicle speed; and when the first distance is equal to or greater than the first predetermined distance, starts the vehicle before the predetermined time has elapsed since the display of the proceed signal and drives the vehicle to the target stopping position where the first distance becomes less than the first predetermined distance.

4. A driving assistance method according to any one of claims 1 to 3, wherein, when setting the detection range, the driving assistance device detects the width of a road on which the crosswalk that the pedestrian can enter is provided, and if the width is less than a predetermined width, sets the detection range on the sidewalk of the road corresponding to both ends of the crosswalk that the pedestrian can enter, and if the width is equal to or greater than the predetermined width, sets the detection range on the sidewalk corresponding to the end of the crosswalk that the pedestrian can enter that is closer to the lane that the vehicle will enter after turning right or left.

5. The driving assistance method according to any one of claims 1 to 4, wherein the driving assistance device detects a second distance between the vehicle and one of the ends of the crosswalk that the pedestrian can enter, the end being closer to the lane that the vehicle will enter after turning right or left; if the second distance is less than a second predetermined distance, maintains the stopped state of the vehicle for the predetermined time; and if the second distance is equal to or greater than the second predetermined distance, starts the vehicle before the predetermined time has elapsed since the proceed signal was displayed, and drives the vehicle to the target stopping position at the predetermined acceleration.

6. The driving assistance method according to any one of claims 1 to 5, wherein the driving assistance device detects a third distance between the vehicle and the pedestrian present within the detection range, and if the third distance is less than a third predetermined distance, maintains the stopped state of the vehicle for the predetermined time, and if the third distance is equal to or greater than the third predetermined distance, starts the vehicle before the predetermined time has elapsed since the display of the proceed signal, and drives the vehicle to the target stopping position at the predetermined acceleration.

7. A driving assistance method according to any one of claims 1 to 6, wherein the driving assistance device calculates a fourth distance required for the vehicle to travel to the crosswalk where the pedestrian can enter, and if the fourth distance is less than a fourth predetermined distance, maintains the stopped state of the vehicle for the predetermined time, and if the fourth distance is equal to or greater than the fourth predetermined distance, starts the vehicle before the predetermined time has elapsed since the display of the proceed signal, and causes the vehicle to travel to the target stopping position at the predetermined acceleration.

8. A driving assistance method according to any one of claims 1 to 7, wherein the driving assistance device, if the stopped state of the vehicle is maintained for the predetermined time after the proceed signal is displayed, starts the vehicle after the predetermined time has elapsed, and, if the pedestrian present within the detection range enters the pedestrian crossing before the predetermined time has elapsed after the proceed signal is displayed, releases the brakes of the vehicle before the predetermined time has elapsed after the proceed signal is displayed, and causes the vehicle to drive to the target stopping position at the predetermined acceleration.

9. A driving assistance method according to any one of claims 1 to 8, wherein the driving assistance device sets the predetermined time as the time required for the pedestrian present in the detection range to enter the crosswalk in the direction of travel.

10. A driving assistance method according to any one of claims 1 to 9, wherein the driving assistance device sets the predetermined acceleration to an acceleration that is lower than the acceleration that would be set when there is no pedestrian crossing the crosswalk in the traveling direction.

11. A driving assistance method according to any one of claims 1 to 10, wherein, if a stop line is present within the intersection and in front of the crosswalk where the pedestrian can enter, the driving assistance device sets the position of the stop line as the target stopping position, and if no stop line is present, sets the target stopping position to a position a predetermined distance in front of the crosswalk where the pedestrian can enter.

12. A driving assistance device that autonomously controls the driving of a vehicle, comprising: a setting unit that, when the vehicle is turning right or left at an intersection provided with traffic lights and a crosswalk, stops the vehicle before the intersection in response to the stop signal displayed by the traffic light, and when there is no other vehicle ahead of the vehicle turning right or left in the same direction as the vehicle's traveling direction, sets a detection range for detecting pedestrians that may enter the crosswalk in the vehicle's traveling direction; and a control unit that, when the pedestrian is present within the detection range and the stop signal displayed by the traffic light changes to a go signal, maintains the vehicle's stopped state for a predetermined time after the go signal is displayed, or starts the vehicle before the predetermined time has elapsed after the go signal is displayed, and causes the vehicle to travel at a predetermined acceleration to a target stopping position in front of the crosswalk.

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