JP7599965B2 - Vehicle driving control method and driving control device - Google Patents

Description

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

A conventional method for modeling a road intersection includes receiving a first data set including road lane information, receiving a second data set including vehicle trajectory information for the road intersection structure, determining lane node positions from at least one of the first data set and the second data set, collecting a set of possible links between the lane node positions, evaluating for each link the probability that the link is a legitimate link, assigning a probability value to each link, filtering the links based on a predetermined threshold probability value, generating a set of legitimate links, and creating a model of the intersection structure based on the set of legitimate links (see Patent Document 1).

JP 2016-75905 A

However, the above conventional intersection modeling method has the problem that if neither road lane information nor vehicle trajectory information for the intersection is available, the vehicle cannot travel autonomously through the intersection.

The problem that this invention aims to solve is to provide a driving control method and driving control device for a vehicle that can autonomously drive through intersections without lane markers.

The present invention solves the above problem by estimating intersection exit information based on detected lane marker information and feature information, generating a first target driving trajectory that connects the vehicle's current location to the intersection exit based on the estimated intersection exit information, updating the intersection exit information based on newly detected lane marker information and feature information while autonomously driving to the intersection exit along the first target driving trajectory, and updating the first target driving trajectory based on the updated intersection exit information.

According to the present invention, as the vehicle approaches the intersection exit, the intersection exit is repeatedly estimated based on the detected feature information, thereby improving the accuracy of the intersection exit estimation, and as a result, the vehicle can autonomously travel through intersections without lane markers.

1 is a block diagram showing an embodiment of a vehicle cruise 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 a lane keeping driving control unit included in the control device of FIG. 1 . 1 is a plan view (at the entrance to the intersection) showing an example of a scene in which a vehicle travel control device of the present invention is used to travel through an intersection without lane markers; 1 is a plan view (at the center of the intersection) showing an example of a scene in which a vehicle travel control device of the present invention is used to travel through an intersection without lane markers; 11 is a plan view showing another example of a scene in which the vehicle travels through an intersection without lane markers using the vehicle travel control device of the present invention. FIG. 11 is a plan view showing another example of a scene in which the vehicle travels through an intersection without lane markers using the vehicle travel control device of the present invention. FIG. 4 is a flowchart showing an example of a control process executed by the lane keeping driving control unit of FIG. 3 .

Configuration of the driving control device
Hereinafter, an embodiment of the present invention will 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, in-vehicle 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 in-vehicle LAN, and can send and receive information between them.

The sensor 11 detects the driving state of the vehicle. For example, the sensor 11 may be a front camera that captures an image in front of the vehicle, a side camera that captures an image of the left and right sides of the vehicle, a rear camera that captures an image of the rear of the vehicle, a front radar that detects obstacles in front of the vehicle, a rear radar that detects obstacles behind the vehicle, a side radar that detects obstacles on the left and right sides of the 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 an image of the driver. The sensor 11 may be configured to use one of the above-mentioned multiple sensors, or may be configured to use a combination of two or more types of sensors. The detection results of the sensor 11 are output to the 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 by 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 the position information of various facilities and specific points, and is accessible from the control device 19. The three-dimensional high-precision map information is three-dimensional map information based on the road shape detected when an actual road is driven on using a data acquisition vehicle. The three-dimensional high-precision map information is map information that is associated with detailed and highly accurate position information, such as curved roads and the size of the curve (e.g., curvature or curvature radius), road junctions, branching points, toll gates, and positions 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 only three-dimensional high-precision map information, and may be other map information.

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

The navigation device 15 obtains the current position information of the vehicle from the vehicle position detection device 12, and displays the vehicle's position on a display or the like by 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 the destination and guides the driver along the set route. With this navigation function, the navigation device 15 displays the route to the destination on the map on the display, and notifies the driver of recommended driving behavior along the route by voice or the like.

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 device and a seat device with an embedded vibrator. The presentation device 16 notifies the driver of various presentation information according to the control of the control device 19.

The input device 17 is, for example, a button switch that allows input by manual operation by the driver, a touch panel arranged on a display screen, or a microphone that allows input by the driver's voice. In this embodiment, the driver can input setting information for the presentation information presented by the presentation device 16 by operating the input device 17. Figure 2 is a front view showing a part of the input device 17 of this embodiment, and shows an example consisting of a group of button switches arranged on the spokes of a steering wheel, etc.

The illustrated input device 17 is a button switch used to set the ON/OFF of the autonomous driving control function (autonomous speed control function and autonomous steering control function) of the control device 19. Details of the autonomous driving control function including the autonomous speed control function and the autonomous steering control function will be described later. The input device 17 of this embodiment 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 assistance switch 176.

The main switch 171 is a switch for turning on/off the power supply of the system that realizes the autonomous speed control function and the autonomous steering control function of the control device 19. The resume/accelerate switch 172 is a switch for performing a resume operation such as restarting the autonomous speed control function at the set speed before turning off the autonomous speed control function once and then turning it off, or restarting the autonomous speed control function by the control device 19 after stopping to follow a preceding vehicle (another vehicle traveling in front of the vehicle in the same lane as the vehicle itself. The same applies hereinafter in this specification), or an accelerate operation for increasing the set speed. The set/coast switch 173 is a switch for performing a set operation for starting the autonomous speed control function at the traveling speed, or a coast operation for decreasing the set speed. The cancel switch 174 is a switch for turning off the autonomous speed control function. The vehicle distance adjustment switch 175 is a switch for setting the vehicle distance from the preceding vehicle, and is a switch for selecting one of multiple settings such as short distance, medium distance, and long distance. The lane change assistance switch 176 is a switch for accepting the start of a lane change when the control device 19 confirms with the driver that the lane change should be started. After accepting the start of a lane change, the lane change assistance switch 176 can be pressed for longer than a predetermined time to cancel the acceptance of the lane change suggestion made by the control device 19.

In addition to the button switches shown in FIG. 2, the turn signal lever of the turn signal or other switches of the in-vehicle equipment 14 can 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, the driver can operate the turn signal lever to change lanes in the direction in which the turn signal lever is operated, rather than the proposed lane change. The setting information input by the input device 17 is output to the control device 19.

The drive control device 18 controls the running of the host vehicle in various ways. For example, when the host vehicle runs at a constant speed at a set speed due to 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 an engine vehicle, the operation of the driving motor in an electric vehicle system, and the torque distribution between the internal combustion engine and the driving motor in a hybrid vehicle) and the brake operation in order to accelerate and decelerate the host vehicle to the set speed, and to maintain the running speed. In addition, when the host vehicle runs following a preceding vehicle due to the autonomous speed control function, the drive control device 18 controls the operation of the drive mechanism and the brake operation to achieve the acceleration/deceleration and running speed so that the distance between the host vehicle and the preceding vehicle is constant.

The drive control device 18 also controls the operation of the steering actuator in addition to the above-mentioned drive mechanism and brake operation control by the autonomous steering control function, thereby performing steering control of the host vehicle. For example, when performing lane keeping control by the autonomous steering control function, the drive control device 18 detects lane markers in the host lane (the lane in which the host vehicle is traveling; the same applies hereinafter in this specification) and controls the host vehicle's traveling position in the width direction so that the host vehicle travels at a predetermined position within the host lane. When performing lane change assistance by the lane change assistance function described later, the drive control device 18 controls the host vehicle's traveling position in the width direction so that the host vehicle changes lanes. Furthermore, when performing right/left turn assistance by the autonomous steering control function, the drive control device 18 performs driving control to turn right or left at an intersection or the like. The drive control device 18 controls the driving of the host vehicle according to instructions from the control device 19 described later. Other 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 traveling of the vehicle, 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, as the operating circuit, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc. can be used instead of or in addition to the CPU (Central Processing Unit).

<Functions Realized by the Control Device 19>
The control device 19 executes a program stored in the ROM by the CPU, thereby realizing a driving information acquisition function for acquiring information regarding 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, image information of the driver's face captured by the in-vehicle camera, and other information as driving information.

Furthermore, the control device 19 acquires the current position information of the vehicle from the vehicle position detection device 12 as driving information. The control device 19 also acquires the set destination and the route to the destination from the navigation device 15 as driving information. The control device 19 also acquires position information such as curved roads and the magnitude of the curve (e.g., curvature or curvature radius), merging points, branching points, toll booths, and positions where the number of lanes decreases as driving information from the map database 13. In addition, the control device 19 acquires information on the operation of the in-vehicle device 14 by the driver from the in-vehicle 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 referring to 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 suitable for, for example, lane changing or overtaking, and the determination conditions for such scenes. The control device 19 refers to the table stored in the ROM to determine whether the driving scene in which the host vehicle is traveling is suitable for, for example, lane changing or overtaking.

For example, the following four conditions are set as 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 vehicle itself," "the preceding vehicle is reached within a specified time," and "the direction of the lane change does not satisfy a lane change prohibition condition." In this case, the control device 19 determines whether the vehicle itself satisfies the above conditions based on, for example, the detection results of the forward camera and forward radar included in the sensor 11, the vehicle speed of the vehicle itself detected by the vehicle speed sensor, and the position information of the vehicle itself from the vehicle position detection device 12. If the above conditions are met, the control device 19 determines that the vehicle itself is in a "scene of catching up with a preceding vehicle." This is 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 the driver's 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 the driver's operation also includes the driver performing some operations. Furthermore, the autonomous speed control function and the autonomous steering control function may be functions 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 distance between the vehicles to maintain a distance according to the vehicle speed, with the upper limit set by the driver, and when a preceding vehicle is not detected, drives at a constant speed at the vehicle speed set by the driver. The former is also called 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 from road signs using the sensor 11, or obtains the speed limit from the map information in the map database 13, and automatically sets the set vehicle speed to that speed limit.

To activate the autonomous speed control function, the driver first operates the resume/accelerate switch 172 or the set/coast switch 173 of the input device 17 shown in FIG. 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 is set as is, but if the driver's desired speed is 80 km/h, the resume/accelerate switch 172 can be pressed multiple times to increase the set speed. The "+" mark on 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 set/coast switch 173 can be pressed multiple times to decrease the set speed. The "-" mark on the set/coast switch 173 indicates that this is a switch that decreases the set value. The driver can adjust the desired distance by operating the distance adjustment switch 175 of the input device 17 shown in FIG. 2 and selecting one of several settings, such as short distance, medium distance, or long distance.

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

The vehicle distance control, which follows the preceding vehicle while performing vehicle distance control, is executed when the forward radar of the sensor 11 detects the presence of a preceding vehicle ahead in the vehicle's lane. In vehicle distance control, the drive control device 18 controls the operation of the engine, brakes, and other drive mechanisms while feeding back the vehicle distance data detected by the forward radar so as to maintain the set vehicle distance with the set travel speed as the upper limit. If the preceding vehicle stops while traveling under vehicle distance control, the vehicle stops following the preceding vehicle. Also, if the preceding vehicle starts moving within, for example, 30 seconds after the vehicle stops, the vehicle also starts moving and starts following the preceding vehicle under vehicle distance control again. If the vehicle has been stopped for more than 30 seconds, the vehicle does not start automatically even if the preceding vehicle starts moving, and if the resume/accelerate switch 172 is pressed or the accelerator pedal is depressed after the preceding vehicle starts moving, the vehicle starts following the preceding vehicle under vehicle distance control again.

On the other hand, the autonomous steering control function is a function for controlling the operation of the steering actuator to execute steering control of the vehicle. The autonomous steering control function of this embodiment includes: (1) a lane keeping function (lane width direction maintaining function) that controls the steering to drive, for example, near the center of the lane and assists the driver in steering; (2) a lane change assist function that controls the steering when the driver operates the turn signal lever and assists the steering operation required for lane change; (3) an overtaking assist function that, when a vehicle slower than the set vehicle speed is detected ahead, asks the driver through a display whether to perform an overtaking operation, and when the driver operates the consent switch, controls the steering and assists the overtaking operation; and (4) a route driving assist function that, when the driver has set a destination in a navigation device or the like, asks the driver through a display whether to perform a lane change when the lane change point required for driving according to the route is reached, and controls the steering and assists the lane change when the driver operates the consent switch. When autonomous steering control is executed, autonomous speed control is also executed at the same time, but speed control may be executed by the driver's accelerator and brake operation.

Now, when autonomous driving is performed using the lane keeping function of the autonomous steering control function, the position of the vehicle in the direction of the lane width is controlled by using a forward camera or the like to detect lane markers ahead of the road on which the vehicle is traveling. However, typical intersections do not have lane markers, and there are no landmarks to guide the vehicle. The prior art documents cited in the prior art also describe accumulating a history of the driving trajectory of intersections that have been traveled through in the past, and using this history to autonomously drive through the intersection. However, such a method cannot be used if the intersection has not been traveled through before, or if the shape of the intersection has changed since the vehicle traveled through it.

In the vehicle driving control device 1 according to this embodiment, when autonomous driving through an intersection without lane markers, at the entrance of the intersection, lane marker information of the road on which the vehicle has been traveling is detected, and feature information around the intersection is detected. Based on the detected lane marker information and feature information, intersection exit information is estimated. Based on the estimated intersection exit information, a first target driving trajectory is generated that connects the vehicle's current location and the intersection exit. However, since the accuracy of the intersection exit of the first target driving trajectory generated here is not very high, while autonomous driving from the entrance of the intersection to the intersection exit along the first target driving trajectory, the intersection exit information is updated based on newly detected lane marker information and feature information, and the first target driving trajectory is regenerated based on the updated intersection exit information, and this is repeated until the intersection exit is reached. Below, an embodiment of autonomous driving through an intersection without lane markers is described. FIG. 3 is a block diagram showing an example of a lane keeping driving control unit 190 included in the control device 19.

As shown in FIG. 3, the lane keeping driving control unit 190 of this embodiment includes an intersection exit estimation unit 192, an intersection exit information update unit 193, a first target driving trajectory generation unit 194, a second target driving trajectory generation unit 195, a target trajectory switching unit 196, and a following command value generation unit 197, into which signals or information are read from a driving data storage unit 191, a sensor 11 such as a front camera as a feature detection unit, and a sensor 11 such as a front camera as a lane marker detection unit, and the final command value is output to the drive control device 18. Each unit constituting the lane keeping driving control unit 190 is represented for convenience, and is actually realized by a program stored in ROM.

The driving data storage unit 191 is a database that stores driving information (such as driving trajectory) of the vehicle on roads that the vehicle has traveled on in the past, in association with its location information (such as latitude and longitude). The driving data storage unit 191 is provided, for example, on a server outside the vehicle, and can be accessed by specific users via an Internet line or the like. Even if there is an intersection without lane markers on a frequently traveled commuter route, if the driving trajectory history is stored in the driving data storage unit 191, the data can be read out and the vehicle can travel autonomously. However, if it is a first intersection with no driving history, or if the shape of the intersection has changed, the information in the driving data storage unit 191 cannot be used.

The feature detection unit is a sensor 11 that helps identify the exit of an intersection when traveling from the entrance to the exit of the intersection. A feature means an object that exists on the earth, and here includes objects that help identify the exit of an intersection, such as a median strip, a curb, a traffic light, and a preceding vehicle. Therefore, the feature detection unit includes sensors 11 that can detect such features, such as a front camera that captures an image in front of the vehicle, a side camera that captures an image of the left and right sides of the vehicle, a rear camera that captures an image of the rear of the vehicle, a front radar that detects obstacles in front of the vehicle, a rear radar that detects obstacles behind the vehicle, and a side radar that detects obstacles on the left and right sides of the vehicle.

The lane marker detection unit is a sensor 11 that detects lane markers placed on the road, and mainly includes a front camera that captures images in front of the vehicle, side cameras that capture images of the left and right sides of the vehicle, and a rear camera that captures images behind the vehicle.

Figures 4A and 4B are plan views showing an example of a scene in which the vehicle V autonomously drives through an intersection IS without lane markers using the vehicle driving control device 1 of this embodiment. Figure 4A shows a case in which the current position P0 of the vehicle V is at the entrance P1 of the intersection IS, and Figure 4B shows a case in which the current position P0 of the vehicle V is at the center of the intersection IS. Incidentally, as shown by the outlined arrows, the intersection IS shown in Figures 4A and 4B is a two-lane road (left-hand traffic) extending vertically in the figure, and a two-lane one-way road extending horizontally in the figure from left to right. The vehicle V enters the intersection IS from lane R1 of the left road and travels straight to lane R2 of the right road.

The intersection exit estimation unit 192 estimates the exit information of the intersection IS during travel based on information from the travel data storage unit 191, the sensor 11 which is a feature detection unit, and the sensor 11 which is a lane marker detection unit. The intersection IS exit information includes the position information (coordinates such as latitude and longitude) and attitude angle information (yaw angle of the vehicle) of the exit P2 of the intersection IS. If the travel data storage unit 191 has a travel history, the position information of the exit P2 of the intersection IS and the attitude angle of the vehicle (yaw angle, travel direction) are estimated from the data. If the travel data storage unit 191 does not have a travel history, the lane marker detection unit (sensor 11) first detects the lane marker of the lane R1 on which the vehicle has traveled up to the entrance P1 of the intersection IS, thereby obtaining the position information of the entrance P1 of the intersection IS and the attitude angle of the vehicle. Then, the sensor 11 which is a feature detection unit, for example, a front camera, is used to obtain an image of the forward area captured from the entrance P1 of the intersection IS, and the exit information of the intersection IS is estimated from this image. For example, if a pair of curbs, or a median strip and a curb, are detected in an image of the area ahead captured from the entrance P1 of the intersection IS, it can be estimated that the exit P2 of the intersection IS is located between them.

The intersection exit information update unit 193 sequentially updates the intersection IS exit information estimated by the intersection exit estimation unit 192 based on new detection images by the feature detection unit and new lane marker information detected by the lane marker detection unit acquired while traveling through the intersection IS. For example, in an image of the forward area acquired at the entrance P1 of the intersection IS, only the median strip and curb of the road R2 ahead can be detected, but as the intersection IS exit P2 is approached, if the lane marker detection unit detects lane markers of the road R2 that connects to the intersection IS exit P2, the intersection IS exit P2 can be estimated more accurately using the relationship with the lane markers.

Although not particularly limited, it is preferable to set the update period of the intersection IS exit information in the intersection exit information update unit 193 to a value equal to or smaller than the estimation period of the intersection IS exit information in the intersection exit estimation unit 192. In other words, it is preferable that the intersection exit information update unit 193 is always updated whenever a new estimation is made by the intersection exit estimation unit 192.

The first target driving trajectory generating unit 194 is triggered by arrival at the entrance P1 of the intersection IS to generate a first target driving trajectory T1 for driving through the intersection IS from the entrance P1 to the exit P2. That is, as shown in FIG. 4A, the trigger is arrival at the entrance P1 of the intersection IS where the lane markers of the lane R1 on which the vehicle V has been traveling until then can no longer be detected. Then, as shown in FIG. 4A, the first target driving trajectory T1 is generated using an easing curve, such as a trigonometric function, a polynomial function, a clothoid curve, a spline curve, or a Bezier curve, that smoothly connects the position coordinates of the entrance P1 of the intersection IS, which is the current position P0 of the vehicle V, and the position coordinates of the exit P2 of the intersection IS estimated by the intersection exit estimating unit 192.

In addition, when generating the first target driving trajectory T1 by connecting the entrance P1 of the intersection IS, which is the current position P0 of the vehicle V, and the exit P2 of the intersection IS estimated by the intersection exit estimation unit 192, in addition to connecting the position coordinates of the entrance P1 of the intersection IS and the position coordinates of the exit P2, it is preferable to match the actual attitude angle when arriving at the entrance P1 of the intersection IS to the attitude angle of the start point of the first target driving trajectory T1. This allows the vehicle V to smoothly enter the intersection IS without changing the attitude angle when switching from the end point of the lane R1 to the start point of the first target driving trajectory T1. In addition to or instead of this, the exit information estimated by the intersection exit estimation unit 192 also includes attitude angle information of the vehicle along the lane R2 of the road connected to the exit P2, so it is preferable to match this attitude angle to the attitude angle of the end point of the first target driving trajectory T1. This allows the vehicle V to smoothly exit the intersection IS without changing its attitude angle when switching from the end point of the first target driving trajectory T1 to the start point of lane R2.

5 is a plan view showing another example of a scene in which the vehicle travel control device 1 of the present invention is used to travel through an intersection IS without lane markers. The vehicle V enters the intersection IS from lane R1 on the left road and travels straight to lane R2 on the right road. In this scene, the lanes R1 and R2 are roads on which lane markers exist, so the target travel trajectory when traveling through the lanes R1 and R2 is the second target travel trajectory T2 described later. At the entrance P1 of the intersection IS, the attitude angle of the end point of the second target travel trajectory T2 on lane R1 is made to coincide with the attitude angle of the start point of the first target travel trajectory T1. Similarly, at the exit P2 of the intersection IS, the attitude angle of the end point of the first target travel trajectory T1 is made to coincide with the attitude angle of the start point of the second target travel trajectory T2 on lane R2. At this time, although not particularly limited, it is preferable that the second target driving trajectory T2 after the exit P2 of the intersection IS is generated by extrapolating into a straight line shape that maintains the attitude angle at the exit P2 of the intersection IS or a curved shape that maintains the curvature at the exit P2 of the intersection IS.

6 is a plan view showing yet another example of a scene in which the vehicle travel control device 1 of the present invention is used to travel through an intersection IS without lane markers, in which the vehicle V enters the intersection IS from lane R1 of the road on the right side and turns right onto lane R2 of the road above, and a right-turning vehicle stop line L is marked within the intersection IS. In such a scene, the vehicle must pass through the right-turning vehicle stop line L when traveling through the intersection IS, so the lane marker detection unit detects the right-turning vehicle stop line L, which is point P3 to be passed through within the intersection IS, and the first target travel trajectory generation unit 194 generates a first target travel trajectory T1 that connects the entrance P1 of the intersection IS, point P3 of the right-turning vehicle stop line L, and exit P2 of the intersection IS. At this time, although not particularly limited, the first target driving trajectory T1 may be generated by dividing it into a first target driving trajectory A from the entrance P1 of the intersection IS to point P3 of the right-turn vehicle stop line L, and a first target driving trajectory B from point P3 of the right-turn vehicle stop line L to the exit P2 of the intersection IS, and at point P3 of the right-turn vehicle stop line L, these divided and generated first target driving trajectories A and B may be connected by a transition curve.

The second target driving trajectory generating unit 195 uses lane marker information detected by the sensor 11 (such as a front camera) which is a lane marker detection unit to generate a first target driving trajectory T2 that runs through a predetermined position, for example the center, of the lane identified by a pair of lane markers. In other words, the second target driving trajectory generating unit 195 generates a target driving trajectory when the vehicle is traveling in a lane where a lane marker is present.

The target driving trajectory switching unit 196 selectively switches between the first target driving trajectory generated by the first target driving trajectory generating unit 194 and the second target driving trajectory generated by the second target driving trajectory generating unit 195, and outputs one of them to the following command value generating unit 197. The target driving trajectory switching unit 196 selects the first target driving trajectory T1 at an intersection without lane markers, and selects the second target driving trajectory T2 on a road with lane markers, as the target driving trajectory to be output to the following command value generating unit 197.

Although not particularly limited, when the target driving trajectory switching unit 196 switches between the first target driving trajectory T1 generated by the first target driving trajectory generating unit 194 and the second target driving trajectory T2 generated by the second target driving trajectory generating unit 195, it is preferable that the two driving trajectories are connected by a transition curve.

The following command value generating unit 197 calculates a control command value to be actually output to the drive control device 18 from the target lateral position _Yref and target attitude angle _θref of the first target traveling locus T1 or the second target traveling locus T2 selected by the target traveling locus switching unit 196, and the actual lateral position _Ysens and attitude angle θsens of the host vehicle V detected by the sensor 11. Specifically, the difference ΔY between the target lateral position _Yref and the actual lateral _{position Ysens} of the target traveling loci T1, T2 is calculated, and a lateral position control command value that brings this difference ΔY closer to zero is feedback controlled, thereby making the lateral position of the host vehicle V follow the target traveling loci T1, T2. In addition, the difference Δθ between the target attitude angle θ _ref of the target driving trajectories T1, T2 and the actual attitude angle θ _sens is calculated, and the attitude angle of the host vehicle V is made to follow the target driving trajectories T1, T2 by feedback controlling the control command value for the attitude angle that brings this difference Δθ closer to zero.

<Lane change control processing>
Next, the lane change control process according to this embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing an example of the lane change 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 a predetermined time interval. In addition, it is assumed below that the autonomous driving control function of the control device 19 executes autonomous speed control and autonomous steering control, and performs lane keep control to control the driving position of the host vehicle in the width direction so that the host vehicle drives within the lane at a speed set by the driver.

In step S1 of FIG. 7, the control device 19 determines whether or not a lane keep control start signal has been input. The control device 19 repeats step S1 until a lane keep control start signal has been input. On the other hand, if a lane keep control start signal has been input, the control device 19 proceeds to step S2.

In step S2, the control device 19 uses a sensor 11 (lane marker detection unit) such as a forward camera to detect lane markers on the road currently being traveled, and determines whether or not the lane markers have been detected. If the lane markers have been detected, the process proceeds to step S3, where the second target travel trajectory generation unit 195 generates a second target travel trajectory T2 that travels, for example, through the center of a pair of detected lane markers. Then, in step S4, the following command value generation unit 197 generates a control command value for the host vehicle V to travel along the generated second target travel trajectory T2, and outputs the control command value to the drive control device 18. As a result, the host vehicle V travels on a road marked with lane markers using lane keeping control.

In contrast, if no lane markers are detected on the road currently being traveled in step S2, the process proceeds to step S6, where it is determined whether the location is an intersection without lane markers. Just because no lane markers are detected does not necessarily mean that the location is an intersection, as the lane markers may be partially missing. If the location is not an intersection without lane markers in step S6, the routine ends, but if the location is an intersection without lane markers, the process proceeds to step S7.

In step S7, the intersection exit estimation unit 192 estimates the exit information of the intersection IS during travel based on information from the travel data storage unit 191, the sensor 11 which is a feature detection unit, and the sensor 11 which is a lane marker detection unit. For example, as shown in FIG. 4A, when the vehicle V arrives at the entrance P1 of the intersection IS from the lane R1, the lane markers that were there up until then disappear, so an image of the forward area captured from the entrance P1 of the intersection IS is obtained using a forward camera which is a feature detection unit. If a pair of curbs are detected in front of the intersection IS at this time, the intersection exit estimation unit 192 estimates that the exit P2 of the intersection IS is between them, and sets the estimated exit P2 to approximately the center of the pair of curbs as shown in FIG. 4A.

In the next step S8, the first target driving trajectory generating unit 194 generates a first target driving trajectory T1 that smoothly connects the position coordinates of the entrance P1 of the intersection IS, which is the current position P0 of the vehicle V, and the position coordinates of the exit P2 of the intersection IS estimated by the intersection exit estimating unit 192, as shown in FIG. 4A. Then, in step S9, the following command value generating unit 197 generates a control command value for the vehicle V to drive along the generated first target driving trajectory T1 and outputs it to the drive control device 18. As a result, the vehicle V enters the intersection from the entrance P1 of the intersection IS.

In the next step S10, it is determined whether the vehicle V has arrived at the exit P2 of the intersection IS. If the vehicle V has not arrived, the process returns to step S7. Then, in step S7, the intersection exit estimation unit 192 again estimates the exit information of the intersection IS during the travel based on new information from the travel data accumulation unit 191, the sensor 11 which is the feature detection unit, and the sensor 11 which is the lane marker detection unit. FIG. 4B is a plan view showing the state in which the vehicle has traveled from the entrance P1 of the intersection IS shown in FIG. 4A to the center of the intersection IS. While traveling through the intersection IS along the initially generated first target travel trajectory T1, the intersection exit estimation unit 192 continues to acquire new information from the travel data accumulation unit 191, the sensor 11 which is the feature detection unit, and the sensor 11 which is the lane marker detection unit, and the closer the exit P2 of the intersection IS is, the higher the accuracy of the intersection IS exit information based on the new information from the sensor 11 which is the feature detection unit and the sensor 11 which is the lane marker detection unit becomes.

For example, at the entrance P1 of the intersection IS, only a pair of curbs on the road R2 ahead can be detected, and the exit P2 is estimated to be the center of the pair of curbs as shown in FIG. 4A. However, as the vehicle approaches the exit P2 of the intersection IS, if the lane marker detection unit detects a lane marker on the road R2 that connects to the exit P2 of the intersection IS, the exit P2 of the intersection IS can be estimated to be the center between the central lane marker and the curb as shown in FIG. 4B.

Therefore, in the next step S8, the first target driving trajectory generating unit 194 regenerates the first target driving trajectory T1 that smoothly connects the position coordinates of the entrance P1 of the intersection IS, which is the current position P0 of the vehicle V, and the position coordinates of the exit P2 of the intersection IS re-estimated by the intersection exit estimating unit 192, as shown in FIG. 4B. Then, in step S9, the following command value generating unit 197 generates a control command value for the vehicle V to drive along the updated first target driving trajectory T1 and outputs it to the drive control device 18. As a result, the vehicle V continues to drive toward the updated exit P2 of the intersection IS. In this way, the process of re-estimating the exit P2 of the intersection IS → re-generating the first target driving trajectory T1 → autonomous driving along the regenerated first target driving trajectory T1 is repeated until the vehicle V arrives at the exit P2 of the intersection IS.

When the vehicle V arrives at the exit P2 of the intersection IS, the process proceeds to step S5. If lane keeping control has not ended, the process proceeds to step S2 and the above process is repeated.

As described above, according to the vehicle driving control method and driving control device 1 of this embodiment, the intersection IS exit information is estimated based on the detected lane marker information and feature information, and a first target driving trajectory T1 that connects the current position P0 of the vehicle V and the intersection IS exit P2 is generated based on the estimated intersection IS exit information. Then, while autonomously driving to the intersection IS exit P2 along the first target driving trajectory T1, the intersection IS exit information is updated based on the newly detected lane marker information and feature information, and a control command value for the vehicle V to autonomously drive along the first target driving trajectory T1 is generated while updating the first target driving trajectory T1 based on the updated intersection IS exit information. As a result, the closer the intersection IS exit P2 is, the higher the accuracy of the intersection IS exit information based on new information from the feature detection unit sensor 11 and the lane marker detection unit sensor 11, so that the vehicle can autonomously drive even at an intersection IS without lane markers.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, the update period of the intersection IS exit information used to generate the control command value is set to a value equal to or less than the estimation period of the intersection IS exit information, so that whenever a new estimate is made by the intersection exit estimation unit 192, it is updated by the intersection exit information update unit 193. Therefore, the newest first target driving trajectory T1 can be generated.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, the first target driving trajectory T1 is generated by connecting the detected current position coordinates of the vehicle V and the estimated position coordinates of the exit P2 of the intersection IS with a transition curve, so that smooth driving without any discomfort can be achieved even without lane markers.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, the target attitude angle at the current position P0 of the first target driving trajectory T1 and the target attitude angle at the exit P2 of the intersection IS are generated so as to match both or either of the attitude angle of the host vehicle V at the detected current position P0 and the attitude angle of the host vehicle V at the estimated exit P2 of the intersection IS, so that smooth driving with little change in attitude angle can be achieved at the end points of the first target driving trajectory T1.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, the second target driving trajectory T2 after the exit P2 of the intersection IS is generated by extrapolating into a straight line shape that maintains the attitude angle at the exit P2 of the intersection IS or a curved shape that maintains the curvature at the exit P2 of the intersection IS, so that smooth driving with little change in attitude angle can be achieved at the connection point between the first target driving trajectory T1 and the second target driving trajectory T2.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, a point P3 to be passed through within the intersection IS, for example, a right-turn vehicle stop line L, is detected, and the first target driving trajectory T1 is generated so as to pass through the point P3 to be passed through, so that a driving trajectory that allows accurate stopping at the right-turn vehicle stop line L can be obtained. Furthermore, if the point to be passed through is to avoid an obstacle present at the intersection IS, it is possible to drive through the intersection IS without interfering with the obstacle.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, the first target driving trajectory T1 is generated by dividing it into a first target driving trajectory A from the current position P0 of the vehicle V to the point P3 to be passed through, and a first target driving trajectory B from the point P3 to the exit P2 of the intersection IS, and at the point P3 to be passed through, the divided and generated first target driving trajectories A and B are connected by a transition curve, so that the driving trajectory can be generated with a small computational load.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, on the road connecting to the intersection IS, the second target driving trajectory T2 is generated based on the detected lane marker information, and the second target driving trajectory T2 is updated every time the detected lane marker information is updated. Therefore, even if the detection situation of the lane markers is poor, the accuracy of the driving position within the lane can be improved by sequentially updating it.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, a first target driving trajectory T1 is selected at an intersection IS without lane markers, and a second target driving trajectory T2 is selected on a road with lane markers. At the switching point between the first target driving trajectory T1 and the second target driving trajectory T2, these driving trajectories are connected by a transition curve, so that the vehicle behavior at the time of switching can be suppressed, and the tracking ability of the driving trajectory and the riding comfort are improved.

Reference Signs List 1: Driving control device 11: Sensor 12: Vehicle position detection device 13: Map database 14: In-vehicle equipment 15: Navigation device 16: Presentation device 17: Input device 18: Drive control device 19: Control device V1: Vehicle

Claims (9)

A method for autonomously controlling a vehicle to travel on a road including an intersection without lane markers, comprising:
Detecting lane marker information of roads connected to the intersection and feature information around the intersection;
Estimating exit information for the intersection based on the detected lane marker information and feature information;
generating a first target travel trajectory that connects a current position of the vehicle and an exit of the intersection based on the estimated exit information of the intersection;
updating exit information of the intersection based on newly detected lane marker information and feature information while autonomously traveling along the first target traveling trajectory to an exit of the intersection;
A vehicle driving control method for generating a control command value for the host vehicle to autonomously drive along a first target driving trajectory while updating the first target driving trajectory based on updated intersection exit information,
The estimated intersection exit information includes position coordinates of the estimated intersection exit,
the first target travel trajectory is generated by connecting the detected current position coordinates of the vehicle and the estimated position coordinates of an exit of the intersection with a transition curve;
the estimated intersection exit information includes an attitude angle of the vehicle along a lane at the estimated intersection exit;
A vehicle driving control method in which a target attitude angle at a current location on the first target driving trajectory and a target attitude angle at an exit of the intersection are generated so as to match both or one of the attitude angle of the vehicle at the detected current location and the attitude angle of the vehicle at the estimated exit of the intersection. A method for autonomously controlling a vehicle to travel on a road including an intersection without lane markers, comprising:
Detecting lane marker information of roads connected to the intersection and feature information around the intersection;
Estimating exit information for the intersection based on the detected lane marker information and feature information;
generating a first target travel trajectory that connects a current position of the vehicle and an exit of the intersection based on the estimated exit information of the intersection;
updating exit information of the intersection based on newly detected lane marker information and feature information while autonomously traveling along the first target traveling trajectory to an exit of the intersection;
A vehicle driving control method for generating a control command value for the host vehicle to autonomously drive along a first target driving trajectory while updating the first target driving trajectory based on updated intersection exit information,
A vehicle driving control method in which a second target driving trajectory after an exit of the intersection is generated by extrapolating to a straight line shape that maintains the attitude angle at the exit of the intersection or a curved shape that maintains the curvature at the exit of the intersection. 3. The vehicle cruise control method according to claim 1 , wherein an update period of the intersection exit information used for generating the control command value is set to a value equal to or shorter than an estimated period of the intersection exit information. Detecting a point to be passed through within the intersection;
The vehicle travel control method according to any one of claims 1 to 3 , wherein the first target travel locus is generated so as to pass through the via point. The first target travel trajectory is generated by dividing it into a first target travel trajectory from a current position of the vehicle to the point to be passed through and a first target travel trajectory from the point to be passed through to an exit of an intersection;
5. The vehicle travel control method according to claim 4 , wherein the first target travel locus generated by dividing the first target travel locus is connected by a transition curve at the via point. Detecting lane marker information of a road connected to the intersection;
generating a second target driving locus based on detected lane marker information on a road connected to the intersection;
The vehicle driving control method according to any one of claims 1 to 5 , further comprising updating the second target driving locus every time the detected lane marker information is updated. At an intersection without lane markers, the first target driving path is selected;
Selecting the second target driving path on a road having lane markers;
7. The vehicle travel control method according to claim 6, wherein the first target travel locus and the second target travel locus are connected by a transition curve at a switching point between the first target travel locus and the second target travel locus. A vehicle driving control device including a processor for autonomously driving a host vehicle on a road including an intersection without lane markers,
The processor,
Detecting lane marker information of roads connected to the intersection and feature information around the intersection;
Estimating exit information for the intersection based on the detected lane marker information and feature information;
generating a first target travel trajectory that connects a current position of the vehicle and an exit of the intersection based on the estimated exit information of the intersection;
updating the estimated intersection exit information based on newly detected lane marker information and feature information while traveling along the first target travel path to an intersection exit;
Regenerating the first target travel trajectory based on the updated intersection exit information;
A vehicle driving control device that generates a control command value for a host vehicle to autonomously drive along a regenerated first target driving trajectory ,
The estimated intersection exit information includes position coordinates of the estimated intersection exit,
the first target travel trajectory is generated by connecting the detected current position coordinates of the vehicle and the estimated position coordinates of an exit of the intersection with a transition curve;
the estimated intersection exit information includes an attitude angle of the vehicle along a lane at the estimated intersection exit;
A vehicle driving control device that generates a target attitude angle at a current location of the first target driving trajectory and a target attitude angle at an exit of the intersection so as to match both or one of the attitude angle of the vehicle at the detected current location and the estimated attitude angle of the vehicle at the exit of the intersection . A vehicle driving control device including a processor for autonomously driving a host vehicle on a road including an intersection without lane markers,
The processor,
Detecting lane marker information of roads connected to the intersection and feature information around the intersection;
Estimating exit information for the intersection based on the detected lane marker information and feature information;
generating a first target travel trajectory that connects a current position of the vehicle and an exit of the intersection based on the estimated exit information of the intersection;
updating the estimated intersection exit information based on newly detected lane marker information and feature information while traveling along the first target travel path to an intersection exit;
Regenerating the first target travel trajectory based on the updated intersection exit information;
A vehicle driving control device that generates a control command value for a host vehicle to autonomously drive along a regenerated first target driving trajectory,
A vehicle driving control device that generates a second target driving trajectory after an exit of the intersection by extrapolating to a straight line shape that maintains the attitude angle at the exit of the intersection or a curved shape that maintains the curvature at the exit of the intersection.

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