JP7788045B2 - Vehicle driving control method and driving control device - Google Patents

Description

The present invention relates to a vehicle driving control method and driving control device.

When traveling straight through an offset intersection where the lanes connecting the entrance and exit of the intersection are offset to the left and right, a vehicle control device is known that sets two virtual lane markings within the intersection that extrapolate the vehicle's lane at the entrance and the vehicle's lane at the exit, determines a target trajectory within the intersection from the virtual lane markings, and controls the vehicle to stay in lane along this target trajectory, thereby performing cruise control at the offset intersection (see Figures 9A and 9B of Patent Document 1).

International Publication No. 2018/179252

However, with the above-mentioned conventional vehicle control systems, when autonomously driving through an offset intersection, the vehicle's travel path and the travel path of an oncoming vehicle may come close to each other within the intersection, causing a sense of uneasiness for the vehicle occupants.

The problem that this invention aims to solve is to provide a vehicle driving control method and driving assistance device that can alleviate the anxiety of occupants when autonomously driving through offset intersections.

The present invention solves the above problem by determining whether an intersection through which a vehicle is traveling straight is an offset intersection offset to the left or right relative to the vehicle's direction of travel. If the intersection is an offset intersection, the system calculates the degree of proximity between the vehicle's planned travel path from the entrance to the exit of the intersection and the planned travel path of an oncoming vehicle in the oncoming lane of the vehicle's planned travel path. The system then determines whether a close-in area exists where the distance between the vehicle's planned travel path and the oncoming vehicle's planned travel path is less than a predetermined value. If a close-in area is determined to exist, the system corrects the lateral position of the vehicle's planned travel path in the close-in area so that it moves away from the oncoming vehicle's planned travel path, or by slowing down the vehicle.

The present invention provides a vehicle driving control method and driving assistance device that alleviates occupant anxiety when autonomously driving through offset intersections.

1 is a block diagram showing an embodiment of a vehicle travel control device according to the present invention; FIG. 2 is a front view showing a part of the input device of FIG. 1 . 2 is a block diagram showing an example of an offset intersection control unit included in the driving control device of FIG. 1 . FIG. FIG. 10 is a plan view illustrating a scene in which a vehicle travels through an offset intersection. FIG. 1 is a plan view (part 1) showing an example of a scene in which a vehicle travels through an offset intersection using a cruise control device of the present invention. FIG. 2 is a plan view (part 2) showing an example of a scene in which a vehicle travels through an offset intersection using the driving control device of the present invention. 5B is a plan view (part 1) for explaining a control process for correcting the lateral position of the planned travel path of the host vehicle in the travel scene of FIG. 5A; FIG. FIG. 5B is a plan view (part 2) for explaining the control process for correcting the lateral position of the planned travel path of the host vehicle in the travel scene of FIG. 5A; 5A to 5D are diagrams illustrating the control process for decelerating the host vehicle in the driving scene of FIG. 5A. FIG. 10 is a plan view (part 1) showing another example of a scene in which a vehicle travels through an offset intersection using the cruise control device of the present invention. FIG. 10 is a plan view (part 2) showing another example of a scene in which a vehicle travels through an offset intersection using the cruise control device of the present invention. 8B is a plan view for explaining a control process for correcting the lateral position of the planned travel path of the host vehicle in the travel scene of FIG. 8A. FIG. FIG. 10 is a plan view showing yet another example of a scene in which the cruise control device of the present invention is used to travel through an offset intersection. 9B is a plan view (part 1) for explaining a control process for correcting the lateral position of the planned travel path of the host vehicle in the travel scene of FIG. 9A; FIG. 9B is a plan view (part 2) for explaining the control process for correcting the lateral position of the planned travel path of the host vehicle in the travel scene of FIG. 9A; FIG. 4 is a flowchart showing an example of a control process executed by the offset intersection traveling control unit of FIG. 3 .

<Configuration of driving control device>
An embodiment of the present invention will now be described with reference to the drawings. Fig. 1 is a block diagram showing the configuration of a vehicle cruise control device 1 according to this embodiment. The cruise control device 1 of this embodiment is also an embodiment for carrying out a vehicle cruise control method according to the present invention.

As shown in FIG. 1, the driving control device 1 of this embodiment includes a sensor 11, a vehicle position detection device 12, a map database 13, on-board equipment 14, a navigation device 15, a presentation device 16, an input device 17, a drive control device 18, and a control device 19. These devices are connected, for example, by a CAN (Controller Area Network) or other on-board LAN, and can send and receive information between them.

Sensor 11 detects the driving state of the host vehicle. Examples of sensors 11 include a front camera that captures images in front of the host vehicle, side cameras that capture images of the left and right sides of the host vehicle, a rear camera that captures images behind the host vehicle, a front radar that detects obstacles in front of the host vehicle, a rear radar that detects obstacles behind the host vehicle, a side radar that detects obstacles on the left and right sides of the host vehicle, a vehicle speed sensor that detects the vehicle speed, a touch sensor (capacitive sensor) that detects whether the driver is holding the steering wheel, and an in-vehicle camera that captures images of the driver. Sensor 11 may be configured to use one of the multiple sensors described above, or a combination of two or more types of sensors. The detection results of sensor 11 are output to control device 19 at predetermined time intervals.

The vehicle position detection device 12 includes a GPS unit, a gyro sensor, a vehicle speed sensor, and the like. The vehicle position detection device 12 detects radio waves transmitted from multiple satellite communications via the GPS unit and periodically acquires position information of the target vehicle (the vehicle itself). The vehicle position detection device 12 also detects the current position of the target vehicle based on the acquired position information of the target vehicle, angle change information acquired from the gyro sensor, and vehicle speed acquired from the vehicle speed sensor. The position information of the target vehicle detected by the vehicle position detection device 12 is output to the control device 19 at predetermined time intervals.

The map database 13 is a memory that stores three-dimensional high-precision map information, including location information for various facilities and specific locations, and is accessible from the control device 19. The three-dimensional high-precision map information is based on road shapes detected when a data acquisition vehicle is driven on actual roads. The three-dimensional high-precision map information is map information that associates detailed and highly accurate location information, such as curved roads and the size of those curves (e.g., curvature or radius of curvature), road junctions, branching points, toll booths, and locations where the number of lanes decreases, as well as map information, as three-dimensional information. However, the map information stored in the map database of the present invention is not limited to three-dimensional high-precision map information, and may be other map information.

The on-board devices 14 are various devices mounted on the vehicle and are operated by the driver. Examples of such on-board devices include the steering wheel, accelerator pedal, brake pedal, turn signals, wipers, lights, the horn, and other specific switches. When operated by the driver, the on-board devices 14 output operation information to the control device 19.

The navigation device 15 obtains the current location information of the vehicle from the vehicle location detection device 12 and displays the vehicle's location on a display or the like, overlaying it on map information for guidance. The navigation device 15 also has a navigation function that, when the driver inputs a destination, calculates a route to that destination and guides the driver along the set route. Using this navigation function, the navigation device 15 displays the route to the destination on a map on the display, and also notifies the driver of recommended driving behaviors along the route by voice or other means.

The presentation device 16 includes various displays such as a display provided in the navigation device 15, a display built into the rearview mirror, a display built into the meter section, and a head-up display projected on the windshield. The presentation device 16 also includes devices other than displays, such as speakers in an audio system and seat devices with embedded vibrators. The presentation device 16 notifies the driver of various presentation information under the control of the control device 19.

The input device 17 is, for example, a button switch that can be manually operated by the driver to input, a touch panel located on a display screen, or a microphone that can accept voice input from the driver. In this embodiment, the driver can operate the input device 17 to input setting information for the presentation information presented by the presentation device 16. Figure 2 is a front view showing a portion of the input device 17 of this embodiment, showing an example consisting of a group of button switches located on the spokes of a steering wheel, etc.

The illustrated input device 17 is a button switch used to turn the autonomous driving control functions (autonomous speed control function and autonomous steering control function) provided by the control device 19 on/off. Details of the autonomous driving control functions, including the autonomous speed control function and autonomous steering control function, will be described later. In this embodiment, the input device 17 includes a main switch 171, a resume/accelerate switch 172, a set/coast switch 173, a cancel switch 174, a vehicle distance adjustment switch 175, and a lane change assist switch 176.

The main switch 171 is a switch for turning ON/OFF the power supply to the system that realizes the autonomous speed control function and autonomous steering control function of the control device 19. The resume/accelerate switch 172 is a switch for performing a resume operation, such as temporarily turning OFF the autonomous speed control function and then restarting it at the set speed before turning OFF, or for following a preceding vehicle (another vehicle traveling ahead in the same lane as the subject vehicle; the same applies hereinafter in this specification) and then restarting it using the control device 19, or an accelerate operation, which increases the set speed. The set/coast switch 173 is a switch for performing a set operation, which starts the autonomous speed control function at the current traveling speed, or a coast operation, which decreases the set speed. The cancel switch 174 is a switch for turning OFF the autonomous speed control function. The distance adjustment switch 175 is a switch for setting the distance from the preceding vehicle, selecting one of several settings, such as short distance, medium distance, or long distance. The lane change assistance switch 176 is a switch for agreeing to the start of a lane change when the control device 19 confirms with the driver that the lane change should begin. After agreeing to the start of a lane change, the driver can cancel the agreement to the lane change suggestion made by the control device 19 by pressing the lane change assistance switch 176 for longer than a predetermined period of time.

In addition to the button switches shown in FIG. 2, the turn signal lever of a turn signal or other switches of the in-vehicle equipment 14 can also be used as the input device 17. For example, when the control device 19 suggests whether to change lanes through autonomous control, the driver can turn on the turn signal switch to input consent or permission to the lane change. Also, when the control device 19 suggests whether to change lanes through autonomous control, if the driver operates the turn signal lever, the lane change will not be in the suggested direction, but will instead occur in the direction in which the turn signal lever is operated. The setting information input by the input device 17 is output to the control device 19.

The drive control device 18 controls the driving of the host vehicle in various ways. For example, when the host vehicle is driving at a constant speed using the autonomous speed control function, the drive control device 18 controls the operation of the drive mechanism (including the operation of the internal combustion engine in engine vehicles, the operation of the traction motor in electric vehicles, and the torque distribution between the internal combustion engine and the traction motor in hybrid vehicles) and braking to accelerate and decelerate the host vehicle and maintain the driving speed so that the host vehicle reaches the set speed. Furthermore, when the host vehicle is driving following a leading vehicle using the autonomous speed control function, the drive control device 18 controls the operation of the drive mechanism and braking to achieve acceleration/deceleration and driving speed so that the distance between the host vehicle and the leading vehicle remains constant.

The drive control device 18 also controls the steering of the vehicle using its autonomous steering control function by controlling the operation of the steering actuator in addition to controlling the operation of the drive mechanism and brakes described above. For example, when performing lane keeping control using the autonomous steering control function, the drive control device 18 detects lane markers in the vehicle's lane (the lane in which the vehicle is traveling; the same applies hereinafter in this specification) and controls the vehicle's traveling position in the vehicle's width direction so that the vehicle travels at a predetermined position within the lane. When performing lane change assistance using the lane change assistance function described below, the drive control device 18 controls the vehicle's traveling position in the vehicle's width direction so that the vehicle changes lanes. When performing right/left turn assistance using the autonomous steering control function, the drive control device 18 controls the vehicle's traveling position to turn right or left at an intersection, etc. The drive control device 18 controls the vehicle's traveling according to instructions from the control device 19 described below. Other well-known methods can also be used as driving control methods by the drive control device 18.

The control device 19 includes a ROM (Read Only Memory) that stores a program for controlling the vehicle's driving, a CPU (Central Processing Unit) that executes the program stored in the ROM, and a RAM (Random Access Memory) that functions as an accessible storage device. Note that, instead of or in addition to the CPU (Central Processing Unit), an MPU (Micro Processing Unit), DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), etc. can be used as the operating circuit.

<<Functions Realized by the Control Device 19>>
The control device 19 executes a program stored in the ROM using the CPU to realize a driving information acquisition function for acquiring information about the driving state of the vehicle, a driving scene determination function for determining the driving scene of the vehicle, and an autonomous driving control function for autonomously controlling the driving speed and/or steering of the vehicle. Each function of the control device 19 will be described below.

The driving information acquisition function of the control device 19 is a function that allows the control device 19 to acquire driving information related to the driving state of the vehicle. For example, the control device 19 acquires image information of the outside of the vehicle captured by the front camera, rear camera, and side camera of the sensor 11 as driving information. The control device 19 also acquires the detection results of the front radar, rear radar, and side radar as driving information. Furthermore, the control device 19 acquires vehicle speed information of the vehicle detected by the vehicle speed sensor of the sensor 11, the attitude angle and yaw rate of the vehicle detected by the gyro sensor, and image information of the driver's face captured by the in-vehicle camera as driving information.

Furthermore, the control device 19 acquires the current position information of the vehicle as driving information from the vehicle position detection device 12. The control device 19 also acquires the set destination and the route to the destination as driving information from the navigation device 15. Furthermore, the control device 19 acquires position information such as curved roads and the size of the curve (e.g., curvature or curvature radius), merging points, branching points, toll booths, and locations where the number of lanes decreases as driving information from the map database 13. In addition, the control device 19 acquires information on the driver's operation of the on-board device 14 from the on-board device 14 as driving information. The above is the driving information acquisition function realized by the control device 19.

The driving scene determination function of the control device 19 is a function that determines the driving scene in which the host vehicle is traveling by referencing a table stored in the ROM of the control device 19. The table stored in the ROM of the control device 19 stores, for each driving scene, driving scenes that are suitable for, for example, lane changes or overtaking, and the conditions for determining such scenes. The control device 19 refers to the table stored in ROM to determine whether the driving scene in which the host vehicle is traveling is suitable for, for example, lane changes or overtaking.

For example, suppose four conditions are set as the conditions for determining a "scene of catching up with a preceding vehicle": "there is a preceding vehicle ahead," "the speed of the preceding vehicle is less than the set speed of the subject vehicle," "the preceding vehicle is reached within a specified time," and "the direction of the lane change does not pose a lane change prohibition condition." In this case, the control device 19 determines whether the subject vehicle satisfies the above conditions based on, for example, the detection results from the forward camera and forward radar included in the sensor 11, the subject vehicle's speed detected by a vehicle speed sensor, and the subject vehicle's position information from the subject vehicle position detection device 12. If the above conditions are met, the control device 19 determines that the subject vehicle is in a "scene of catching up with a preceding vehicle." This concludes the driving scene determination function realized by the control device 19.

The autonomous driving control function of the control device 19 is a function that allows the control device 19 to autonomously control the driving of the vehicle without relying on driver operation. The autonomous driving control function of the control device 19 includes an autonomous speed control function that autonomously controls the driving speed of the vehicle, and an autonomous steering control function that autonomously controls the steering of the vehicle. Note that autonomous control without relying on driver operation also includes some operations being performed by the driver. Furthermore, the autonomous speed control function and the autonomous steering control function may be independent of each other, or may be functions related to each other. The autonomous speed control function and the autonomous steering control function of this embodiment are described below.

The autonomous speed control function is a function that, when a preceding vehicle is detected, follows the preceding vehicle while controlling the vehicle distance to maintain a distance according to the vehicle speed, with the upper limit set by the driver. When a preceding vehicle is not detected, the vehicle drives at a constant speed set by the driver. The former is also called vehicle distance control, and the latter is called constant speed control. The autonomous speed control function may also include a function that detects the speed limit of the road being traveled on from road signs using the sensor 11, or obtains the speed limit from map information in the map database 13, and automatically sets that speed limit to the set vehicle speed.

To activate the autonomous speed control function, the driver first operates the resume/accelerate switch 172 or set/coast switch 173 on the input device 17 shown in Figure 2 to input the desired driving speed. For example, if the set/coast switch 173 is pressed while the vehicle is traveling at 70 km/h, the current driving speed will be set as is. However, if the driver's desired speed is 80 km/h, the driver can simply press the resume/accelerate switch 172 multiple times to increase the set speed. The "+" sign next to the resume/accelerate switch 172 indicates that this is a switch that increases the set value. Conversely, if the driver's desired speed is 60 km/h, the driver can simply press the set/coast switch 173 multiple times to decrease the set speed. The "-" sign next to the set/coast switch 173 indicates that this is a switch that decreases the set value. Furthermore, the driver can adjust the desired distance between vehicles by operating the distance adjustment switch 175 on the input device 17 shown in Figure 2 and selecting one of several settings, such as short distance, medium distance, or long distance.

Constant speed control, which keeps the vehicle traveling at a constant speed set by the driver, is executed when the forward radar of sensor 11 detects that there is no preceding vehicle ahead in the vehicle's lane. During constant speed control, the drive control device 18 controls the operation of the engine, brakes, and other drive mechanisms while feeding back vehicle speed data from the vehicle speed sensor to maintain the set traveling speed.

Distance control, which follows a preceding vehicle while performing distance control, is executed when the forward radar of sensor 11 detects the presence of a preceding vehicle ahead in the vehicle's lane. During distance control, the drive control device 18 controls the operation of drive mechanisms such as the engine and brakes while feeding back inter-vehicle distance data detected by the forward radar to maintain a set inter-vehicle distance, with a set travel speed as the upper limit. If the preceding vehicle stops while driving under distance control, the vehicle will also stop after the preceding vehicle. Furthermore, if the preceding vehicle starts moving within, say, 30 seconds after the vehicle has stopped, the vehicle will also start moving and resume following distance control. If the vehicle has been stopped for more than 30 seconds, the vehicle will not automatically start moving even if the preceding vehicle starts moving. After the preceding vehicle starts moving, pressing the resume/accelerate switch 172 or depressing the accelerator pedal will resume following distance control.

On the other hand, the autonomous steering control function is a function for controlling the steering of the vehicle by controlling the operation of the steering actuator. The autonomous steering control function of this embodiment includes: (1) a lane-keeping function (lane width direction maintenance function) that controls the steering to keep the vehicle near the center of the lane and assists the driver in steering; (2) a lane-change assistance function that controls the steering when the driver operates the turn signal lever and assists the driver in steering necessary to change lanes; (3) an overtaking assistance function that, when a vehicle slower than the set vehicle speed is detected ahead, displays a message asking the driver whether to perform an overtaking maneuver, and, if the driver operates an acceptance switch, controls the steering to assist the overtaking maneuver; and (4) a route driving assistance function that, when the driver has set a destination in a navigation system or the like, displays a message asking the driver whether to perform a lane change when the vehicle reaches a lane-change point required for traveling along the route, and, if the driver operates an acceptance switch, controls the steering to assist the lane change. When autonomous steering control is performed, autonomous speed control is also performed simultaneously; however, speed control may be performed by the driver's accelerator and brake operation.

When using the autonomous driving control function described above to drive autonomously through an intersection, particularly when driving through an intersection where the center line of the vehicle's lane connecting the entrance and exit of the intersection is not in a straight line but is offset to the left or right (hereinafter referred to as an offset intersection), it is necessary to set the vehicle's driving trajectory through the intersection in advance and have the vehicle pass along this driving trajectory. The prior art documents cited in the prior art section describe setting virtual lane markings within the intersection that extrapolate the vehicle's lane at the entrance and exit of the intersection, determining a target trajectory (driving trajectory) within the intersection from the virtual lane markings, and controlling the vehicle's lane-keeping behavior through the offset intersection. However, in prior art documents, the target trajectory (driving path) of the vehicle is set by taking into consideration only the relative positions of the vehicle's own lane at the entrance and exit of the intersection. Therefore, depending on the relative positions of the vehicle's own lane and the oncoming lane (the lane opposite the vehicle's own lane; the same applies hereinafter in this specification), the vehicle's target trajectory (driving path) and the oncoming vehicle's driving path may become close to each other within the intersection, causing the occupants to feel uneasy.

In this embodiment, the vehicle driving control device 1 controls the driving of the host vehicle when the host vehicle drives autonomously through an offset intersection, taking into account the relative positions of the host vehicle's lane and the oncoming vehicle's lane at the entrance and exit of the intersection. Specifically, the system calculates the degree of proximity between the host vehicle's driving path and the oncoming vehicle's driving path from the relative positions of the host vehicle's lane and the oncoming vehicle's lane at the entrance and exit of the intersection. If a close area exists where the distance between the host vehicle's driving path and the oncoming vehicle's driving path is less than a predetermined value, the system corrects the lateral position of the host vehicle's driving path within the intersection to a position away from the oncoming vehicle's driving path or decelerates the host vehicle, thereby alleviating the occupant's anxiety.

An embodiment of autonomous driving through an offset intersection will be described below with reference to Figures 3 to 9C. The following describes an example in which the present invention is applied to a driving scene in accordance with traffic laws stipulating that vehicles keep to the left and people keep to the right, such as Japanese traffic laws. However, the present invention can also be applied to driving scenes in which traffic laws stipulate that vehicles keep to the right and people keep to the left by switching the terms in the following description.

Figure 3 is a block diagram showing an example of an offset intersection driving control unit 190 included in the control device 19. The offset intersection driving control unit 190 of this embodiment comprises a driving data storage unit 191, an offset determination unit 192, a proximity calculation unit 193, a vehicle speed calculation unit 194, a driving route calculation unit 195, and a following command value generation unit 196, which incorporates signals or information from the map database 13 and sensors 11 such as a front camera acting as an intersection detection unit, and outputs final command values to the drive control device 18. These components of the offset intersection driving control unit 190 are merely a convenient representation of the functional configuration achieved by the execution of an information processing program in the control device 19, and are actually realized by a program stored in ROM.

The driving data storage unit 191 is a database that stores correlated driving information (such as driving trajectory) and location information (such as latitude and longitude) of the vehicle on roads that the vehicle has traveled on in the past. The driving data storage unit 191 is provided, for example, on a server external to the vehicle, and is accessible to specific users via an internet connection. If the driving data storage unit 191 contains driving trajectory history, that data can be read out and used for autonomous driving. It is also possible to update past driving information to reflect current driving information, and to store, for example, a speed profile within an intersection IS (described below) or a correction value for the lateral position of the vehicle V1 relative to the planned driving trajectory TR. However, if the intersection IS is a first-time intersection with no driving history, or if the shape of the intersection IS has changed, the information in the driving data storage unit 191 cannot be used. The driving data storage unit 191 is not an essential component of the present invention and may be omitted as necessary.

The intersection detection unit is a sensor 11 that detects intersections IS on the driving route of the host vehicle V1, and mainly includes a front camera that captures images in front of the host vehicle V1 and side cameras that capture images of the left and right sides of the host vehicle V1. The intersection detection unit identifies the shape of the intersection IS from intersection information acquired by the front camera, etc. The intersection information includes location information (latitude and longitude, etc.) of the entrance and exit of the intersection IS, and information on the roads connecting to the entrance and exit of the intersection IS (number of lanes, lane width, etc.). The intersection detection unit may acquire intersection information from map information stored in the map database 13 to identify the shape of the intersection IS, or may identify the shape of the intersection IS using both intersection information acquired by the front camera, etc. and intersection information acquired from the map information.

Figure 4 is a plan view showing an example of a scene in which the host vehicle V1 autonomously travels through an offset intersection. The intersection IS shown in Figure 4 is an offset intersection where two one-lane roads (with left-hand traffic) extending in the vertical, horizontal, and lateral directions of the figure intersect, and the driving lanes L1 and L2 connecting to the entrance of the intersection IS are offset to the left of the driving lanes L3 and L4 connecting to the exit of the intersection IS. Note that the entrance and exit of the intersection IS here refer to the entrance and exit as viewed from the direction of travel of the host vehicle V1. The host vehicle V1 enters the intersection IS from the right-hand driving lane L1, passes through the intersection IS along the planned driving trajectory TR, and exits into the left-hand driving lane L3.

The term "entrance to an intersection IS" refers to the area where the driving lane L1 in which the host vehicle V1 is traveling and the oncoming driving lane L2 connect to the intersection IS. It is not particularly limited, but for example, it could be the range from the line (dashed line) obtained by extending the stop line SL1 of the driving lane L1 in which the host vehicle V1 is traveling in the width direction of the driving lanes L1 and L2 to the intersection IS. The term "exit" refers to the area where the driving lane L3 into which the host vehicle V1 enters after passing the intersection IS and the oncoming driving lane L4 connect to the intersection IS. It is not particularly limited, but for example, it could be the range from the line (dashed line) obtained by extending the stop line SL4 of the oncoming driving lane L4 in the width direction of the driving lanes L3 and L4 to the intersection IS.

The offset determination unit 192 determines whether the intersection IS that the host vehicle V1 is about to pass through is an offset intersection based on map information acquired from the map database 13, vehicle travel information (such as travel trajectory) acquired from the travel data storage unit 191, and intersection information acquired from the intersection detection unit. For example, in the scene shown in Figure 4, if the entry position IP and exit position OP of the host vehicle V1 are not on a straight line relative to the host vehicle V1's direction of travel (solid arrow), the intersection IS is determined to be an offset intersection. The entry position IP is, but is not limited to, the center of the stop line SL1 of the host vehicle's lane connecting to the entrance of the intersection IS, i.e., the driving lane L1. The exit position OP is, but is not limited to, the center of the driving lane L3 that the host vehicle V1 will enter after passing the intersection IS, on an extension of the stop line SL4 of the oncoming lane connecting to the exit of the intersection IS, i.e., the driving lane L4. The offset determination unit 192 outputs the determination result, along with the intersection information, to the proximity calculation unit 193.

The determination of whether or not an intersection is an offset intersection may be based on one of the map information acquired from the map database 13, the vehicle's driving information (such as driving trajectory) acquired from the driving data accumulation unit 191, and the intersection information acquired by the intersection detection unit, or may be based on a combination of two or more pieces of information. Furthermore, other well-known methods can also be used by the offset determination unit 192 to determine whether an intersection is an offset intersection.

When the proximity calculation unit 193 receives a determination result from the offset determination unit 192 that the intersection IS is an offset intersection, it calculates the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2 within the intersection IS before the host vehicle V1 arrives at the entrance to the intersection IS, and calculates the degree of proximity between the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2.

The scene shown in Figure 5A is a scene at the offset intersection shown in Figure 4 where the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2 are calculated, and the degree of proximity between the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2 is calculated. First, as shown in Figure 5A, the proximity degree calculation unit 193 generates, as the planned driving trajectory TR of the host vehicle V1, a transition curve that smoothly connects the entry position IP at the entrance of the intersection IS and the exit position OP at the exit of the intersection IS using, for example, a trigonometric function, a polynomial function, a clothoid curve, a Bezier curve, etc. (dashed-dotted arrow).

Next, the proximity calculation unit 193 generates the planned driving trajectory ER of the oncoming vehicle V2 by extending the actual travel path FR of the oncoming vehicle V2 straight up to the extension of the stop line SL1 of the driving lane L1 (diagonal arrow) at the entrance of the driving lane L4, which is the oncoming lane of the planned driving trajectory TR of the host vehicle V1 (the exit of the intersection IS from the host vehicle V1's perspective), for example, to the stop line SL4. This makes it possible to determine the planned driving trajectory ER of the oncoming vehicle V2 when it passes through the intersection IS at the closest distance to the host vehicle V1.

The planned travel trajectory TR of the host vehicle V1 is not limited to a transition curve and may be a straight line connecting the entry position IP and the exit position OP. Connecting the entry position IP and the exit position OP with a simple straight line reduces the computational load when calculating the planned travel trajectory TR of the host vehicle V1. Furthermore, when there is no oncoming vehicle V2 in the oncoming lane, the planned travel trajectory ER of the oncoming vehicle V2 may be generated by treating the straight line connecting the centers of the vehicle widthwise from a predetermined distance before the stop line SL4 of the driving lane L4 to the stop line SL4 as the elapsed trajectory FR and extending it straight to the extension of the stop line SL1 of the driving lane L1. The predetermined distance is not particularly limited, but may be a distance appropriate for the elapsed trajectory FR, such as 11 meters, the distance traveled per second by a vehicle traveling at 40 km/h. This allows the planned travel trajectory ER of the oncoming vehicle V2 to be calculated based on the road shape of the oncoming lane, even when there is no oncoming vehicle V2.

Next, the proximity degree calculation unit 193 calculates the degree of proximity between the planned travel trajectory TR of the host vehicle V1 and the planned travel trajectory ER of the oncoming vehicle V2. As shown in FIG. 5A, the proximity degree calculation unit 193 detects an approach position CP where the distance between the planned travel trajectory TR of the host vehicle V1 and the planned travel trajectory ER of the oncoming vehicle V2 is equal to or less than a predetermined value, and if the approach position CP is detected, it determines that the planned travel trajectory TR of the host vehicle V1 and the planned travel trajectory ER of the oncoming vehicle V2 are approaching each other. On the other hand, if the approach position CP is not detected, it determines that the planned travel trajectory TR of the host vehicle V1 and the planned travel trajectory ER of the oncoming vehicle V2 are not approaching each other. The predetermined value is not particularly limited, but may be, for example, 2 m, which corresponds to approximately the width of the vehicle.

Furthermore, when the proximity degree calculation unit 193 determines that the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2 are approaching each other, it identifies an approach area CA. As shown in FIG. 5A , if there are multiple approach positions CP, the approach area CA may be a range including the multiple approach positions CP, or a range near a specific approach position CP. Alternatively, a line segment connecting the multiple approach positions CP on the planned driving trajectory TR of the host vehicle V1 may be identified as the approach area CA. In this approach area CA, the driver's anxiety can be alleviated by performing deceleration control of the host vehicle V1 (described below) or by performing control to correct the lateral position of the planned driving trajectory TR of the host vehicle V1 to a position away from the planned driving trajectory ER of the oncoming vehicle V2. The approach degree calculation unit 193 outputs information on the approach position CP and approach area CA, along with the planned travel trajectory TR of the host vehicle V1 and the planned travel trajectory ER of the oncoming vehicle V2, to the vehicle speed calculation unit 194 and the travel path calculation unit 195.

Incidentally, even if the shape of the intersection IS is the same, depending on the relative positions of the host vehicle V1 and the oncoming vehicle V2, the planned travel path TR of the host vehicle V1 and the planned travel path ER of the oncoming vehicle V2 may not approach each other, i.e., the approach position CP may not be detected and the approach area CA may not be identified. For example, as shown in Figure 5B, this is a scene where the relative positions of the host vehicle V1 and the oncoming vehicle V2 are swapped at an offset intersection with the same shape as the intersection IS shown in Figures 4 and 5A.

In the scene shown in FIG. 5B , an approach position CP is not detected where the distance between the planned travel path TR of the host vehicle V1, which connects the entry position IP where the host vehicle V1 enters the intersection IS and the exit position OP where the host vehicle V1 exits the intersection IS, and the planned travel path ER of the oncoming vehicle V2, which is a straight extension of the actual travel path FR of the oncoming vehicle V2 up to the stop line SL1 in the driving lane L1, to the stop line SL4 in the driving lane L4, is less than a predetermined value. Therefore, it is determined that the planned travel path TR of the host vehicle V1 and the planned travel path ER of the oncoming vehicle V2 are not approaching each other, and the approach area CA is not identified. In such a case, the host vehicle V1 is not decelerated or the lateral position of the planned travel path TR of the host vehicle V1, as described below, is not corrected. In other words, the host vehicle V1 passes through the intersection IS by following the planned travel path TR as is using normal speed control for passing through an intersection.

In this way, the proximity calculation unit 193 calculates the relative positions of the driving lanes L1, L2, L3, and L4 connected to the intersection IS, as well as the relative positions of the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2, and determines whether there is a possibility that the host vehicle V1 and the oncoming vehicle V2 will approach each other, thereby selecting the intersection IS to be controlled. Even at an offset intersection, if the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2 are not approaching each other, that is, if the approach position CP is not detected and there is no approach area CA, the host vehicle V1 and the oncoming vehicle V2 will not approach each other, and therefore unnecessary driving control is not performed. This allows the host vehicle V1 to travel smoothly through the offset intersection.

Returning to FIG. 3, the vehicle speed calculation unit 194 sets a speed profile for the host vehicle V1 when passing through the intersection IS based on the information received from the proximity degree calculation unit 193, including the planned travel trajectory TR of the host vehicle V1, the planned travel trajectory ER of the oncoming vehicle V2, the approach position CP, and the approach area CA. Figures 7(a) to 7(c) are diagrams showing changes in the vehicle speed of the host vehicle V1 in the scene shown in FIG. 5A. The horizontal axis corresponds to the travel position of the host vehicle V1 within the intersection IS, and the vertical axis shows changes in the vehicle speed of the host vehicle V1. As shown in FIGS. 7(a) and 7(b), when the host vehicle V1 travels along the planned travel trajectory TR, the vehicle speed calculation unit 194 decelerates the host vehicle V1 so that its speed when traveling through the approach area CA is minimized. In other words, the speed profile is set so that the host vehicle V1 travels at a lower speed while traveling through the approach area CA than when traveling outside the approach area CA.

As shown in FIG. 7(c), the vehicle speed calculation unit 194 may further decelerate the host vehicle V1 within the approach area CA so that the host vehicle V1 reaches its lowest speed at the position in the approach area CA where the planned travel path TR of the host vehicle V1 and the planned travel path ER of the oncoming vehicle V2 are closest to each other, for example, in the scene shown in FIG. 5A, the position where the planned travel path TR of the host vehicle V1 and the planned travel path ER of the oncoming vehicle V2 intersect. Furthermore, as shown in FIG. 7(d), the host vehicle V1 normally gradually accelerates in line with the legal speed limit for the travel lane L3 into which it enters after passing through the intersection IS (see dashed line). However, if the approach area CA is located near the exit of the intersection IS, a speed profile that suppresses the acceleration of the host vehicle V1 may be set (see solid line). Setting the speed profile in this manner can reduce the sense of anxiety felt by the occupants.

Furthermore, when the host vehicle V1 passes through the intersection IS, the vehicle speed calculation unit 194 may set the speed profile based on whether or not there is an oncoming vehicle V2 that the host vehicle V1 will pass within the intersection IS. For example, if a front camera or the like serving as sensor 11 detects an oncoming vehicle V2 attempting to enter the intersection IS from the driving lane L4, the vehicle speed calculation unit 194 calculates the respective vehicle speeds of the oncoming vehicle V2 and the host vehicle V1. Then, if the oncoming vehicle V2 travels along the planned driving trajectory ER of the oncoming vehicle V2, the vehicle speed calculation unit 194 calculates the position where the host vehicle V1 and the oncoming vehicle V2 will pass each other. At this time, if the vehicle speed calculation unit 194 determines that the position where the host vehicle V1 and the oncoming vehicle V2 will pass each other is within the approach area CA, the vehicle speed calculation unit 194 calculates a deceleration so that the position where the host vehicle V1 and the oncoming vehicle V2 will pass each other is outside the approach area CA, and sets the speed profile of the host vehicle V1.

In the scene shown in FIG. 5A, the deceleration of the host vehicle V1 until it reaches the approach area CA is set high, and the speed profile is set so that the host vehicle V1 travels at a low speed and passes the oncoming vehicle V2 just before the approach area CA. Depending on the position of the approach area CA within the intersection IS, the deceleration of the host vehicle V1 until it reaches the approach area CA may be set low, and the speed profile may be set so that the host vehicle V1 passes the oncoming vehicle V2 after passing the approach area CA. This makes it possible to adjust the position where the host vehicle V1 and the oncoming vehicle V2 pass each other without changing the planned travel trajectory TR of the host vehicle V1 calculated by the proximity degree calculation unit 193, thereby reducing the calculation load and easing the anxiety of the occupants with relatively easy control.

On the other hand, if the front camera or other sensor 11 does not detect an oncoming vehicle V2 attempting to enter the intersection IS from the driving lane L4, the vehicle speed calculation unit 194 does not need to set a speed profile that decelerates the host vehicle V1 to minimize its speed when traveling through the approach area CA, or adjusts the deceleration so that the position where the host vehicle V1 and oncoming vehicle V2 pass each other is outside the approach area CA. This is because, if there is no oncoming vehicle V2 that the host vehicle V1 will pass within the intersection IS, unnecessary deceleration control is not performed, allowing the host vehicle V1 to pass the intersection IS smoothly. The vehicle speed calculation unit 194 outputs the set speed profile to the following command value generation unit 196.

The driving path calculation unit 195 corrects the lateral position of the planned driving path TR of the host vehicle V1 based on information received from the proximity degree calculation unit 193 regarding the planned driving path TR of the host vehicle V1, the planned driving path ER of the oncoming vehicle V2, the approach position CP, and the approach area CA. Specifically, the driving path calculation unit 195 corrects the lateral position of the planned driving path TR of the host vehicle V1 in the approach area CA, i.e., the driving position of the host vehicle V1 in the width direction, so as to move away from the planned driving path ER of the oncoming vehicle V2.

The scenes shown in Figures 6A and 6B depict calculations of a corrected driving trajectory CR1 at the intersection IS shown in Figure 5A, where the lateral position of the planned driving trajectory TR of the host vehicle V1 is corrected. As shown in Figure 6A, from the entry position IP to the approach area CA, the host vehicle V1 follows the planned driving trajectory TR, and the driving trajectory in the approach area CA is corrected so that the host vehicle V1 moves away from the planned driving trajectory ER of the oncoming vehicle V2, i.e., so that the lateral position is shifted to the left in the direction of travel. Then, after passing through the approach area CA, a corrected driving trajectory CR1 is calculated so that the host vehicle V1 again follows the planned driving trajectory TR.

The driving path calculation unit 195 may correct the lateral position of the host vehicle V1 so that it is farthest from the oncoming vehicle V2 at a position in the approach area CA where the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2 are closest, such as the intersection of the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2, as shown in FIG. 6A. By correcting the planned driving trajectory TR of the host vehicle V1 in the approach area CA where the host vehicle V1 and the oncoming vehicle V2 are likely to approach each other, the lateral distance between the host vehicle V1 and the oncoming vehicle V2 is ensured, thereby reducing the anxiety of the occupants.

In addition, as shown in FIG. 6B, the driving path calculation unit 195 may correct the lateral position of the planned driving trajectory TR of the host vehicle V1 in the approach area CA and before and after it. Specifically, the lateral position of the host vehicle V1 when traveling through the approach area CA is corrected so that the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2 are the furthest apart, and the lateral position is also corrected before and after the approach area CA to match this maximum correction of the lateral position. This makes it possible to set a corrected driving trajectory CR1 that smoothly connects the entry position IP at the entrance of the intersection IS, the approach area CA where the lateral position is corrected to the maximum, and the exit position OP at the exit of the intersection IS. This makes it possible to stabilize the driving behavior of the host vehicle V1 within the intersection IS while maintaining the lateral distance between the host vehicle V1 and the oncoming vehicle V2.

Furthermore, when the host vehicle V1 passes through an intersection IS, the travel path calculation unit 195 may determine whether to correct the lateral position of the planned travel trajectory TR based on whether there is an oncoming vehicle V2 that the host vehicle V1 will pass within the intersection IS. For example, if an oncoming vehicle V2 attempting to enter the intersection IS from the travel lane L4 is detected by a front camera or the like as sensor 11, and the host vehicle V1 and the oncoming vehicle V2 pass each other in the approach area CA, the lateral position may be corrected so that the host vehicle V1 is farthest from the planned travel trajectory ER of the oncoming vehicle V2 at the position where the host vehicle V1 and the oncoming vehicle V2 pass each other, thereby ensuring a lateral distance between the host vehicle V1 and the oncoming vehicle V2.

In contrast, if an oncoming vehicle V2 attempting to enter the intersection IS from driving lane L4 is not detected, the lateral position of the planned travel trajectory TR of the host vehicle V1 may not be corrected. This is because, by not performing unnecessary lateral position corrections when there is no oncoming vehicle V2 passing the host vehicle V1 within the intersection IS, the host vehicle V1 can pass the intersection IS smoothly without changing the original planned travel trajectory TR.

The following command value generation unit 196 calculates a control command value to be actually output to the drive control device 18 based on the speed profile within the intersection IS generated by the vehicle speed calculation unit 194 and the corrected driving trajectory CR1 generated by the driving path calculation unit 195. The vehicle V1 is caused to follow the corrected driving trajectory CR1 by controlling the longitudinal position based on the speed profile generated by the vehicle speed calculation unit 194 and controlling the lateral position based on the corrected driving trajectory CR1 generated by the driving path calculation unit 195. The following command value generation unit 196 may control either the longitudinal position or the lateral position of the vehicle V1, or may control both the longitudinal position and the lateral position. Furthermore, when the vehicle V1 passes through the intersection IS, the following unit 196 may determine whether to control the longitudinal position or the lateral position of the vehicle V1 and switch between these controls. By performing appropriate control according to the driving environment of the vehicle V1, the vehicle V1 can pass through the intersection IS smoothly.

Note that the shape of the offset intersection is not limited to the examples shown in Figures 4 to 6B above. The present invention can be applied to offset intersections of various shapes, such as offset intersections where the number of lanes connecting to the entrance of the intersection IS differs from the number of lanes connecting to the exit of the intersection IS. Figures 8A to 8C are plan views showing another example of a scene in which the host vehicle V1 autonomously drives through an intersection IS using the cruise control device 1 of this embodiment. The intersection IS shown in Figures 8A to 8C is an offset intersection where two single-lane roads (left-hand traffic) extending up, down, left, and right in the figure intersect, and the lanes L3, L4, and L5 connecting to the exit of the intersection IS are offset to the left of the lanes L1 and L2 connecting to the entrance of the intersection IS. The lane L5 is a zebra zone ZA, which is basically an area where vehicles do not travel. In this embodiment, a zebra zone ZA is used, but the same applies to a central reservation or the like.

8A shows a scene in which the host vehicle V1 passes through an intersection IS where the driving lane L1 in which the host vehicle V1 is traveling faces the driving lane L4 in which the oncoming vehicle V2 is traveling. As described above, when the proximity calculation unit 193 acquires intersection information from the offset determination unit 192, it calculates the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2 at the intersection IS before the host vehicle V1 arrives at the entrance to the intersection IS, and calculates the degree of proximity between the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2. The planned driving trajectory TR of the host vehicle V1 is a trajectory that enters the intersection IS from an entry position IP, turns left while traveling through the intersection IS, and then turns right when traveling halfway through the intersection IS to an exit position OP. In contrast, the planned driving trajectory ER of the oncoming vehicle V2 is a trajectory obtained by extending the elapsed trajectory FR that the oncoming vehicle V2 has traveled until it reaches the stop line SL4 in the driving lane L4 in a straight line to the stop line SL1 in the driving lane L1.

The intersection IS shown in Figure 8A is an offset intersection where the driving lane L1 in which the host vehicle V1 is traveling and the driving lane L4 in which the oncoming vehicle V2 is traveling face each other. Therefore, near the entrance to the intersection IS, an approach position CP is detected where the distance between the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2 is less than a predetermined value, and an approach area CA is also identified.

In contrast, the offset intersection shown in Figure 8B has the same number of lanes connecting to the entrance and exit of the intersection IS as the offset intersection shown in Figure 8A, but the intersection IS is shaped so that the lane L1 in which the host vehicle V1 is traveling faces the lane L5 of the zebra zone ZA. In the scene shown in Figure 8B, the lane L1 in which the host vehicle V1 is traveling does not face the lane L4 in which the oncoming vehicle V2 is traveling. Therefore, an approach position CP where the distance between the planned travel path TR of the host vehicle V1 and the planned travel path ER of the oncoming vehicle V2 is less than a predetermined value is not detected, and an approach area CA is not identified.

In the scene shown in FIG. 8A, an approach area CA where the host vehicle V1 and oncoming vehicle V2 approach each other is identified, so as described above, the vehicle speed calculation unit 194 sets a speed profile for controlling the longitudinal position of the host vehicle V1, and the travel path calculation unit 195 calculates a corrected travel trajectory CR1 for controlling the lateral position of the host vehicle V1, as shown in FIG. 8C. In contrast, in the scene shown in FIG. 8B, an approach area CA where the host vehicle V1 and oncoming vehicle V2 approach each other is not identified. Therefore, no control is performed to decelerate the host vehicle V1 or to correct the lateral position of the planned travel trajectory TR of the host vehicle V1. In other words, the host vehicle V1 passes through the intersection IS by traveling following the planned travel trajectory TR as is, using normal speed control for passing through an intersection.

However, as shown in Figures 9A to 9C, if the driving lane L5 of the guidance zone (zebra zone) ZA forms a right-turn lane for making a right turn at intersection IS, for example, there will be an oncoming vehicle V3 traveling in driving lane L5. In such a case, similar to the scene shown in Figure 8A, the driving lane L1 in which the host vehicle V1 is traveling and the driving lane L5 in which the oncoming vehicle V3 is traveling will face each other. Therefore, as shown in Figure 9A, the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V3 approach each other near the entrance to intersection IS, and the approach position CP is detected and the approach area CA is also identified.

When an approach area CA is identified, the vehicle speed calculation unit 194 sets a speed profile for controlling the longitudinal position of the host vehicle V1 as described above, and the travel path calculation unit 195 calculates a corrected travel trajectory CR1 for controlling the lateral position of the host vehicle V1, as shown in FIG. 9B. In the scene shown in FIG. 9A, the oncoming vehicle V3 enters the intersection IS from the travel lane L5 and then turns right through the intersection IS. Therefore, compared to when the oncoming vehicle V3 passes through the intersection IS and enters the travel lane L2, the oncoming vehicle V3 approaches the planned travel trajectory TR of the host vehicle V1 more closely. Therefore, the travel path calculation unit 195 corrects the lateral position of the planned travel trajectory TR of the host vehicle V1 so that it moves further away from the planned travel trajectory ER of the oncoming vehicle V3.

In the scene shown in FIG. 9C , the driving path calculation unit 195 calculates a corrected driving trajectory CR2 (solid arrow) by further correcting the lateral position of the corrected driving trajectory CR1 (dashed arrow) obtained by correcting the lateral position of the planned driving trajectory TR of the host vehicle V1, thereby ensuring a lateral distance between the host vehicle V1 and the oncoming vehicle V3 when the oncoming vehicle V3 turns right. Similarly, for controlling the longitudinal position, the vehicle speed calculation unit 194 sets a speed profile that reduces the speed of the host vehicle V1 when the oncoming vehicle V3 turns right and passes through the intersection IS, compared to when the oncoming vehicle V3 passes through the intersection IS and enters the driving lane L2. This makes it possible to alleviate the anxiety of the occupants even in driving scenes where the oncoming vehicle V3 turns right and approaches the host vehicle V1.

Incidentally, even if there is no oncoming vehicle V3 traveling in the driving lane L5, when the vehicle speed calculation unit 194 and the driving path calculation unit 195 detect that the driving lane L5 opposite the driving lane L1 in which the host vehicle V1 is traveling is a right-turn lane, they may execute the above-mentioned deceleration control of the host vehicle V1 and control to correct the lateral position of the planned driving trajectory TR of the host vehicle V1. This is because, depending on the position of the guidance zone (zebra zone) ZA in the driving lane L5, the timing at which the oncoming vehicle V3 is detected may be later than the timing at which the host vehicle V1 arrives at the entrance to the intersection IS.

Offset intersection driving control processing
Next, the offset intersection driving control process according to this embodiment will be described with reference to Figure 10. Figure 10 is a flowchart showing an example of the offset intersection driving control process executed by the control device 19 of this embodiment. The driving control process described below is executed by the control device 19 at predetermined time intervals. In the following, it is assumed that the autonomous driving control function of the control device 19 executes autonomous speed control and autonomous steering control, and performs lane keeping control to control the driving position of the host vehicle in the width direction so that the host vehicle travels within the lane at a speed set by the driver.

In step S1 of Figure 10, the intersection detection unit (sensor 11) detects an intersection IS on the driving route of the host vehicle V1 using a forward camera or the like. Next, in step S2, the offset determination unit 192 determines whether the intersection IS that the host vehicle V1 is about to pass through is an offset intersection. If it is determined that the intersection IS is not an offset intersection, the offset intersection driving control is terminated and driving control for passing through a normal intersection is executed. On the other hand, if it is determined that the intersection IS is an offset intersection, the process proceeds to step S3.

If the result of the determination in step S2 is that the intersection IS is an offset intersection, the proximity calculation unit 193 calculates the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2 at the intersection IS before the host vehicle V1 arrives at the entrance to the intersection IS.

First, as shown in Figure 5A, the proximity calculation unit 193 calculates the planned driving trajectory TR of the host vehicle V1, which is a trajectory connecting the entry position IP at the entrance to the intersection IS to the exit position OP at the exit of the intersection IS.

Next, as shown in FIG. 5A, the proximity calculation unit 193 calculates the planned driving trajectory ER of the oncoming vehicle V2 by extending the elapsed trajectory FR of the oncoming vehicle V2 in a straight line to a position on an extension of the stop line SL1 of the driving lane L1. The elapsed trajectory FR is the trajectory actually traveled by the oncoming vehicle V2 on its way to the stop line SL4 of the driving lane L4. Note that if there is no oncoming vehicle V2, the planned driving trajectory ER of the oncoming vehicle V2 may be calculated using the elapsed trajectory FR as a straight line connecting the centers of the driving lane L4 in the width direction from a distance a predetermined distance before the stop line SL4 to the stop line SL4.

In step S4, the proximity calculation unit 193 calculates the degree of proximity between the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2. As shown in FIG. 5A, the proximity position CP at which the distance between the planned driving trajectory TR of the host vehicle V1 and the planned driving trajectory ER of the oncoming vehicle V2 is equal to or less than a predetermined value is detected.

In the following step S5, the proximity degree calculation unit 193 determines whether an approach area CA exists. If the approach position CP is detected in step S4, the approach area CA is identified, so it is determined that the approach area CA exists and the process proceeds to step S6. In contrast, if the approach position CP is not detected in step S4, the approach area CA is not identified either, so it is determined that the approach area CA does not exist. If it is determined that the approach area CA does not exist, the host vehicle V1 and oncoming vehicle V2 are not approaching each other even at the offset intersection, so the offset intersection driving control is terminated and the host vehicle V1 passes through the intersection IS by following the planned driving trajectory TR of the host vehicle V1 as is using speed control for passing through a normal intersection.

If the result of the judgment in step S5 is that an approach area CA is present, then in step S6, the vehicle speed calculation unit 194 sets a speed profile that decelerates the host vehicle V1 so that the vehicle speed is minimized in the approach area CA, as shown in FIG. 7(a), for example. This allows the longitudinal position to be controlled so that the host vehicle V1 travels at a slower speed while traveling in the approach area CA than when traveling outside the approach area CA.

In the following step S7, the driving path calculation unit 195 sets a corrected driving trajectory CR1 by correcting the lateral position of the planned driving trajectory TR of the host vehicle V1 in the approach area CA so that it is away from the planned driving trajectory ER of the oncoming vehicle V2, as shown in FIG. 6A. The corrected driving trajectory CR1 may be a trajectory in which the lateral position is corrected so that it is farthest from the planned driving trajectory ER of the oncoming vehicle V2 in the approach area CA, as shown in FIG. 6B, and the lateral position is corrected before and after the approach area CA. This makes it possible to control the lateral position so that a lateral distance is maintained between the host vehicle V1 and the oncoming vehicle V2 while traveling through the approach area CA.

In step S8, the following command value generation unit 196 outputs a control command value to the drive control device 18 based on the speed profile within the intersection IS generated by the vehicle speed calculation unit 194 and the corrected driving trajectory CR1 generated by the driving path calculation unit 195, and causes the host vehicle V1 to enter the intersection IS.

In step S9, the host vehicle V1 passes through the intersection IS while controlling its longitudinal position based on the speed profile within the intersection IS generated by the vehicle speed calculation unit 194, and controlling its lateral position based on the corrected driving trajectory CR1 generated by the driving path calculation unit 195. In step S10, when the host vehicle V1 passes through the intersection IS and exits into driving lane L3 shown in Figures 6A and 6B, the following command value generation unit 196 ends the offset intersection driving control.

As described above, the vehicle cruise control method and cruise control device 1 of this embodiment determine whether an intersection IS that the host vehicle V1 is about to pass through in a straight line is an offset intersection offset to the left or right of the host vehicle V1's straight-line direction. If the intersection IS is an offset intersection, the system calculates the degree of proximity between the host vehicle V1's planned travel path TR from the entrance to the exit of the intersection IS and the planned travel path ER of the oncoming vehicle V2 in the oncoming lane of the host vehicle V1's planned travel path TR. The system then determines whether an approach area CA exists in which the distance between the host vehicle V1's planned travel path TR and the oncoming vehicle V2's planned travel path ER is less than a predetermined value. If an approach area CA is determined to exist, the system either corrects the lateral position of the host vehicle V1's planned travel path TR in the approach area CA to move away from the oncoming vehicle V2's planned travel path ER or decelerates the host vehicle V1 to allow the host vehicle V1 to pass through the intersection IS. This reduces the occupant's anxiety when autonomously driving through an offset intersection.

Furthermore, according to the vehicle cruise control method and cruise control device 1 of this embodiment, the planned cruise trajectory ER of the oncoming vehicle V2 is calculated by extending the trajectory (elapsed trajectory FR) that the oncoming vehicle V2 actually traveled until it reached the entrance to the intersection IS in the oncoming lane. This makes it possible to calculate the planned cruise trajectory ER of the oncoming vehicle V2 when it passes through the intersection IS closest to the host vehicle V1.

Furthermore, according to the vehicle driving control method and driving control device 1 of this embodiment, the speed of the host vehicle V1 is decelerated to a minimum in the approach area CA, so that while traveling in the approach area CA, the host vehicle V1 can be driven at a lower speed than when traveling outside the approach area CA. This further reduces the anxiety of the occupants.

Furthermore, according to the vehicle driving control method and driving control device 1 of this embodiment, the lateral position of the planned driving trajectory TR of the host vehicle V1 is corrected in the approach area CA and before and after it, and in the approach area CA, the lateral position of the planned driving trajectory TR of the host vehicle V1 is corrected so that it is farthest from the planned driving trajectory ER of the oncoming vehicle V2. This ensures a lateral distance between the host vehicle V1 and the oncoming vehicle V2 while traveling through the approach area CA, reducing the anxiety of the occupants. Furthermore, since the planned driving trajectory TR of the host vehicle V1 whose lateral position has been corrected can be made a smooth trajectory, the driving behavior of the host vehicle V1 within the intersection IS can be stabilized.

Furthermore, according to the vehicle cruise control method and cruise control device 1 of this embodiment, when the host vehicle V1 passes through an intersection IS, an oncoming vehicle V2 that will pass the host vehicle V1 within the intersection IS is detected, and if there is an oncoming vehicle V2 that will pass the host vehicle V1 within the intersection IS, the lateral position of the planned travel trajectory TR of the host vehicle V1 in the approach area CA is corrected so as to move away from the planned travel trajectory ER of the oncoming vehicle V2, or the host vehicle V1 is decelerated, thereby allowing the host vehicle V1 to pass the intersection IS. As a result, when there is an oncoming vehicle V2 that will pass the host vehicle V1 within the intersection IS, offset intersection cruise control is performed, thereby preventing unnecessary cruise control from being performed.

Furthermore, according to the vehicle driving control method and driving control device 1 of this embodiment, when an oncoming vehicle V2 is present at an intersection IS, the host vehicle V1 is decelerated so that the position where the oncoming vehicle V2 and the host vehicle V1 pass each other is outside the approach area CA. This makes it possible to adjust the position where the host vehicle V1 and the oncoming vehicle V2 pass each other without changing the planned driving trajectory TR of the host vehicle V1 calculated by the proximity degree calculation unit 193, thereby reducing the calculation load and alleviating the anxiety of the occupants with relatively easy control.

Furthermore, according to the vehicle driving control method and driving control device 1 of this embodiment, when it is determined that an approach area CA exists and the oncoming lane (driving lane S5) in which the oncoming vehicle V3 is traveling is a right-turn lane, the speed of the host vehicle V1 is reduced compared to when the oncoming lane in which the oncoming vehicle V3 is traveling is not a right-turn lane. This makes it possible to alleviate the anxiety of the occupants even in driving situations in which the oncoming vehicle V3 is turning right and approaching the host vehicle V1.

Furthermore, according to the vehicle driving control method and driving control device 1 of this embodiment, when it is determined that an approach area CA exists and the oncoming lane (driving lane S5) in which the oncoming vehicle V3 is traveling is a right-turn lane, the lateral position of the planned driving trajectory TR of the host vehicle V1 in the approach area CA is corrected to be further away from the planned driving trajectory ER of the oncoming vehicle V3 compared to when the oncoming lane in which the oncoming vehicle V3 is traveling is not a right-turn lane. This makes it possible to alleviate the anxiety of the occupants even in driving situations in which the oncoming vehicle V3 is turning right and approaching the host vehicle V1.

The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the scope of the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1... Driving control device 11... Sensor 12... Vehicle position detection device 13... Map database 14... On-board equipment 15... Navigation device 16... Presentation device 17... Input device 18... Drive control device 19... Control device V1... Vehicle V2, V3... Oncoming vehicle L1, L2, L3, L4, L5... Driving lane TR... Planned driving trajectory of vehicle ER... Planned driving trajectory of oncoming vehicle FR... Progress trajectory of oncoming vehicle CR1, CR2... Corrected driving trajectory SL1, SL4, SL5... Stop line IS... Intersection CA... Approach area CP... Approach position

Claims (7)

A driving control method executed by a processor to autonomously control a vehicle traveling on a road including an intersection, comprising:
The processor:
determining whether an intersection through which the host vehicle is about to pass while traveling straight is an offset intersection that is offset to the left or right with respect to the direction of straight travel of the host vehicle;
If the intersection is an offset intersection, detecting whether or not there is an oncoming vehicle passing through the intersection when the host vehicle passes through the intersection;
If there is an oncoming vehicle that will pass within the intersection, calculate, at a timing before the host vehicle arrives at the entrance of the intersection, the distance between a planned travel path of the host vehicle from the entrance to the exit of the intersection and a planned travel path that is a straight extension of a path that an oncoming vehicle in an oncoming lane of the planned travel path of the host vehicle actually traveled until it reaches the entrance of the intersection ,
determining whether or not there is an approach area in which the distance between the planned travel path of the host vehicle and the planned travel path of the oncoming vehicle is equal to or less than a predetermined value;
When it is determined that the approach area exists, the vehicle travel control method allows the vehicle to pass through the intersection by at least one of correcting the lateral position of the planned travel trajectory of the vehicle in the approach area so as to move away from the planned travel trajectory of the oncoming vehicle, or slowing down the vehicle just before the approach area . The processor:
2. The vehicle travel control method according to claim 1 , wherein the speed of the host vehicle is reduced in the approach area so as to be minimized when the host vehicle travels from the entrance to the exit of the intersection . The processor:
correcting a lateral position of a planned travel path of the host vehicle in the approaching region and before and after the approaching region;
3. The vehicle travel control method according to claim 1, wherein a lateral position of the planned travel path of the host vehicle is corrected so as to be farthest from the planned travel path of the oncoming vehicle in the approaching region. The processor:
4. A vehicle driving control method according to claim 1, wherein, when there is an oncoming vehicle passing at the intersection, the host vehicle is decelerated so that the position where the oncoming vehicle and the host vehicle pass each other is outside the approach area. The processor:
5. The vehicle driving control method according to claim 1, wherein when it is determined that the approach area exists and the oncoming lane in which the oncoming vehicle is traveling is a right-turn lane, the speed of the host vehicle is reduced compared to when the oncoming lane in which the oncoming vehicle is traveling is not a right- turn lane. The processor:
When correcting a lateral position of the planned travel path of the host vehicle in the approach area so as to move away from the planned travel path of the oncoming vehicle,
6. A vehicle driving control method according to claim 1, wherein, when it is determined that the approach area exists and the oncoming lane in which the oncoming vehicle is traveling is a right-turn lane, the lateral position of the planned driving trajectory of the host vehicle in the approach area is corrected to be further away from the planned driving trajectory of the oncoming vehicle compared to when the oncoming lane in which the oncoming vehicle is traveling is not a right- turn lane. A driving control device that autonomously controls a vehicle traveling on a road including an intersection,
an offset determination unit that determines whether an intersection that the host vehicle is about to pass through while traveling straight is an offset intersection that is offset to the left or right with respect to the straight traveling direction of the host vehicle;
a proximity degree calculation unit that, if the intersection is an offset intersection, detects whether or not there is an oncoming vehicle that the host vehicle will pass within the intersection when passing through the intersection, and, if there is an oncoming vehicle that the host vehicle will pass within the intersection, calculates, at a timing before the host vehicle arrives at the entrance of the intersection, the distance between a planned travel path of the host vehicle from the entrance to the exit of the intersection and a planned travel path that is a straight extension of a path that an oncoming vehicle in an opposite lane of the planned travel path of the host vehicle actually traveled until it reached the entrance of the intersection ;
a determination unit that determines whether or not there is an approach area in which the distance between the planned travel path of the host vehicle and the planned travel path of the oncoming vehicle is equal to or less than a predetermined value;
and a control unit that, when it is determined that the approach area exists, corrects the lateral position of the vehicle's planned driving trajectory in the approach area so that it moves away from the planned driving trajectory of the oncoming vehicle, or slows down the vehicle just before the approach area , thereby allowing the vehicle to pass through the intersection.