JP7563216B2 - 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.

There is a known driving assistance system that, when changing lanes from the lane in which the vehicle is traveling to another lane, detects multiple other vehicles traveling in the other lane, and if a space between the other vehicles that the vehicle can enter is detected, executes a lane change by decelerating the vehicle and then entering the detected space between the other vehicles (see the driving scenes in Figures 8 to 10 of Patent Document 1).

JP 2015-184722 A

However, with the conventional driving assistance system described above, after the vehicle starts to decelerate in order to change lanes, depending on the situation of the other vehicle traveling in the other lane, it may not be possible to secure sufficient space between the vehicle and the other vehicle. In such cases, the vehicle may be unable to complete the lane change and may stop straddling its own lane and the other lane, causing a problem of impeding the traffic flow of following vehicles.

The problem that the present invention aims to solve is to provide a vehicle driving control method and a vehicle driving control device that can prevent the vehicle from stopping in a state straddling the vehicle's own lane and other lanes when changing lanes through autonomous driving control.

The present invention solves the above problem by identifying a lane change section on the vehicle's travel route where a lane change is to be performed, setting a virtual stop position where the vehicle will stop on the vehicle's lane in the lane change section, decelerating the vehicle to the virtual stop position, determining whether the lane change will be completed before the vehicle reaches the virtual stop position, and if it is determined that the lane change will not be completed before the vehicle reaches the virtual stop position, stopping the vehicle at the virtual stop position and then executing the lane change.

The present invention makes it possible to prevent the vehicle from stopping in a state straddling its own lane and another lane when changing lanes through autonomous driving control.

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 plan view showing an example of lane change control of the driving control device of FIG. 1; 5A and 5B are plan views showing lane change control according to a comparative example of the present invention. 2 is a block diagram showing an example of a lane change control unit included in the driving control device of FIG. 1 . 6A is a diagram showing an example of processing executed by a lane change section identification unit and a virtual stop position setting unit in FIG. 5 , and FIG. 6B is a plan view showing an example of processing executed by a target vehicle identification unit in FIG. 5 . 6A and 6B are plan views each showing a first example of a process executed by the lane change execution determination unit in FIG. 5 . 6 is a plan view showing a second example of a process executed by the lane change execution determination unit in FIG. 5 . 6 is a plan view (upper diagram) showing an example of processing executed by a lane change execution determination unit and a deceleration selection unit in FIG. 5, and a graph showing the deceleration of the host vehicle (lower diagram, speed versus position). 7A to 7D are a plan view showing driving pattern variables stored in the cost setting unit of FIG. 5 and a graph showing an example of lane change costs, respectively. 7A to 7C are respectively a plan view showing driving pattern variables stored in the cost setting unit of FIG. 5 and a graph showing another example of lane change costs. FIG. 6 is a diagram showing an example of a driving pattern and variables stored in a cost setting unit in FIG. 5 . 10A and 10B are plan views each showing an example of a driving scene to which the driving pattern variables of FIGS. 10B to 10D are applied. 11A and 11B are plan views each showing an example of a driving scene to which the driving pattern variables of FIGS. 11A to 11C are applied. 6 is a flowchart showing an example of a control process executed by the lane change control unit of FIG. 5 . 16 is a flowchart (a subroutine of step S5 in FIG. 15 ) showing an example of control processing executed by a cost setting unit and a virtual stop position setting unit in FIG. 5 .

Configuration of the 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, 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 the position information of the vehicle. The vehicle position detection device 12 also detects the current position of the vehicle based on the acquired vehicle position information, angle change information acquired from the gyro sensor, and vehicle speed acquired from the vehicle speed sensor. The vehicle position information 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 input device 17 shown in the figure 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) equipped in 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 in 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 ahead in the same lane as the vehicle itself. The same applies hereinafter in this specification), or an accelerate operation to increase the set speed. The set/coast switch 173 is a switch for setting the autonomous speed control function at the traveling speed, or a coast operation to decrease 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 or not 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 or not to change lanes through autonomous control, when the driver operates the turn signal lever, the lane change is made 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 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 size 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 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 of the vehicle's own lane. In vehicle distance control, the drive control device 18 controls the operation of the drive mechanisms such as the engine and brakes while feeding back the vehicle distance data detected by the forward radar so as to maintain the set vehicle distance with the set driving 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 again under vehicle distance control. 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 again under vehicle distance control.

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.

Here, the lane change assist function of the autonomous steering control function will be described. Note that autonomous speed control is also executed simultaneously with lane change assist. FIG. 3 is a plan view showing an example of lane change control (lane change assist function) executed by the control device 19 of this embodiment. As shown in FIG. 3, when the driver operates the turn signal lever of the vehicle V1, the control device 19 turns on the turn signal, and starts the lane change operation LCP (Lane Change Process, a series of processes for autonomous lane change) when a preset lane change start condition is met. The control device 19 determines whether the lane change start condition is met based on various driving information acquired by the sensor 11. The lane change start conditions are not particularly limited, but examples include the following: (1) the lane is in lane keeping mode; (2) the driver is holding the steering wheel; (3) the vehicle is traveling at a speed of 60 km/h or more; (4) there is a lane in the direction of the lane change; (5) there is space in the lane to which the lane is to be changed so that the lane can be changed; (6) the lane marker type indicates that the lane can be changed; (7) the curvature radius of the road is 250 m or more; and (8) the driver has operated the turn signal lever within one second. Note that when the control device 19 determines that the lane change start conditions are met by the lane change assistance function, even without the driver's instruction, it may suggest to the driver to change lanes by notifying the driver through the presentation device 16.

When the lane change start condition is satisfied, the control device 19 starts the lane change operation LCP. As shown in FIG. 3, the lane change operation LCP in this embodiment includes a lateral movement in which the vehicle V1 moves toward the adjacent lane L2 within the vehicle's lane L1, and a lane change manipulation (LCM) in which the vehicle V1 moves from the vehicle's lane L1 across a lane marker to the adjacent lane L2. While the control device 19 is executing the lane change operation LCP, the control device 19 presents information indicating that the lane change is being performed by autonomous control to the driver via the presentation device 16, and urges the driver to pay attention to the surroundings. When the lane change maneuver LCM is completed, the control device 19 turns off the turn signal and starts executing a lane keeping function in the adjacent lane L2. The lane change maneuver LCP refers to the period from when the turn signal is turned on to when it is turned off by operating the turn signal lever, and the lane change maneuver LCM refers to the period from when the vehicle V1 starts to step on the boundary line between the vehicle's lane L1 and the adjacent lane L2 to when it stops stepping on it.

Now, when executing a lane change using the lane change assistance function of the autonomous steering control function, it is necessary to secure sufficient space for the host vehicle to enter the target lane (the lane into which the host vehicle is changing lanes; the same applies hereinafter in this specification). In this case, if there are multiple other vehicles traveling in the target lane, it is necessary to identify an inter-vehicle space for the host vehicle to enter from among multiple inter-vehicle spaces, and then execute the lane change while closely monitoring the driving conditions of the other vehicles traveling in front of and behind the inter-vehicle space and controlling the speed of the host vehicle.

Figures 4(A) and (B) are plan views showing a driving scene according to a comparative example of the present invention, in which the host vehicle V1 executes a lane change from the host vehicle lane L1 in which the host vehicle V1 is currently traveling to the target lane L2 in which the other vehicles V2 and V3 are traveling. Figure 4(B) shows a state in which the host vehicle V1 has advanced in the traveling direction from the state shown in Figure 4(A).

In the case of the driving scene shown in FIG. 4(A), the host vehicle V1 identifies the space between the other vehicles V2 and V3 (within the diagonal line frame) as the lane change space for the host vehicle to enter, and executes lane change control to enter behind the other vehicle V2 while decelerating. At this time, the other vehicles V2 and V3 traveling on the target lane L2 decelerate to turn left at an intersection in the direction of travel, so the space between the other vehicles V2 and V3 gradually narrows as the host vehicle approaches the intersection. As shown in FIG. 4(B), when the host vehicle V1 decelerates to get behind the other vehicle V2 and attempts to enter the target lane L2, if a sufficient lane change space cannot be secured, the host vehicle V1 has no choice but to abort the lane change. Therefore, a situation occurs in which the host vehicle V1 stops straddling the host vehicle lane L1 and the target lane L2. Stopping temporarily in this way can impede the traffic flow of following vehicles (other vehicles traveling behind the vehicle; the same applies hereinafter in this specification), such as a motorcycle traveling along the lane marker between the vehicle's lane L1 and the target lane L2.

In this way, when near an intersection where there are right and left turns, when other vehicles traveling in the target lane L2 slow down due to a red light, or when other vehicles must stop before the intersection because pedestrians are crossing even when the light is green, the inter-vehicle space that was initially sufficient when the lane-changing space was detected often becomes unable to be secured due to the driving conditions of other vehicles.

Therefore, in the vehicle driving control device 1 of this embodiment, a virtual stop position SP (see black arrow in FIG. 6A) is set on the own lane L1 of the lane change section LC (see dashed frame in FIG. 6A) at which the own vehicle V1 is stopped. If the lane change cannot be completed by the time the lane change is completed before the vehicle reaches the virtual stop position SP, the own vehicle V1 is stopped at the virtual stop position SP without entering the target lane L2. More preferably, even if the turn signal is turned on by operating the turn signal lever, the own vehicle V1 is stopped at the virtual stop position SP without moving laterally within the own lane L1 toward the target lane L2. Below, an embodiment of lane change control using the lane change control unit 190 of the control device 19 will be described with reference to FIGS. 5 to 9. In the following, an example of applying the present invention to a driving scene in which traffic regulations stipulating that vehicles should keep to the left and people should keep to the right, such as Japanese traffic regulations, will be described. However, the present invention can also be applied to driving situations where vehicles follow traffic laws that stipulate that vehicles should drive on the right side of the road by reinterpreting the left and right in the following explanation.

Figure 5 is a block diagram showing an example of a lane change control unit 190 included in the control device 19. The lane change control unit 190 reads signals or information from the map database 13, the vehicle position detection device 12, the object detection unit 112, the target vehicle identification unit 113, the vehicle state acquisition unit 114, the stationary structure detection unit 115, the sensor 11 as the signal recognition unit 116, the destination setting unit 151, and the navigation device 15 as the route setting unit 152, and further outputs a final command value to the drive control device 18. These components constituting the lane change control unit 190 are represented for the sake of convenience, and are actually realized by a program stored in ROM.

First, the destination setting unit 151 receives destination information required to set the driving route of the vehicle V1 from the driver and outputs it to the route setting unit 152. The route setting unit 152 calculates a driving route to the destination based on the current position information of the vehicle V1 output from the vehicle position detection device 12 and the destination information acquired by the destination setting unit 151. At this time, the destination setting unit 151 detects information on points where a lane change is required on the driving route of the vehicle V1. Points where a lane change is required refer to points where the vehicle V1 will deviate from the driving route to the destination if it cannot complete the lane change, such as intersections with right and left turns, merging roads, and branching roads. The route setting unit 152 outputs information on points where a lane change is required to the lane change section identification unit 191 along with the driving route of the vehicle V1.

The lane change section identification unit 191 identifies a lane change section LC where the host vehicle V1 will change lanes based on the current position information of the host vehicle V1 obtained from the host vehicle position detection device 12, and the information on the travel route of the host vehicle V1 and points where a lane change is required obtained from the route setting unit 152. Specifically, the lane change section LC is set to a predetermined distance required for the host vehicle V1 to change lanes from the point where a lane change is required, for example, the stop line of the intersection where the host vehicle V1 needs to turn left as shown in FIG. 6(A), for example, 150 m before the stop line of the intersection in the traveling direction of the host vehicle V1. The host vehicle V1 starts decelerating in this lane change section LC, and enters the target lane L2 from the host vehicle's lane L1, in which the host vehicle V1 is currently traveling, to change lanes.

The predetermined distance required for the host vehicle V1 to execute a lane change is not particularly limited, but may be set based on the time required for the host vehicle V1 to complete the lane change and the speed limits of the host vehicle lane L1 and the target lane L2, or may be set based on the relative positions, relative speeds, and lane change time between the host vehicle V1 and other vehicles traveling in the target lane L2.

The lane change section identification unit 191 determines whether the vehicle V1 has reached the lane change section LC based on the current position information of the vehicle V1 obtained from the vehicle position detection device 12 and the driving route information of the vehicle V1 obtained from the route setting unit 152. When the vehicle V1 reaches the lane change section LC, a lane change control start signal is output to the lane change execution determination unit 192 and the cost setting unit 193.

When a start signal for lane change control is input, the cost setting unit 193 calculates the lane change cost and outputs it to the virtual stop position setting unit 194. The lane change cost is an index of suitability of lane change for the position where the host vehicle V1 executes the lane change in the lane change section LC. When executing autonomous driving control, it is one of the parameters for facilitating judgment by a computer, and the value of the lane change cost according to the driving situation is determined in advance, and these values are applied to the current driving situation. In this embodiment, a case where the lane change cost is "low" indicates that the driving situation is one in which the suitability of lane change is high. That is, it is a driving situation in which the host vehicle V1 is easy to execute a lane change, or a driving situation in which the host vehicle V1 is unlikely to cause discomfort to the following vehicle even if it stops. On the other hand, a case where the lane change cost is "high" indicates that the suitability of lane change is low, and it is a driving situation in which the host vehicle V1 is difficult to execute a lane change, or a driving situation in which the host vehicle V1 is likely to cause discomfort to the following vehicle if it stops. The cost setting unit 193 calculates the value of the lane change cost based on the driving pattern variables described later. Then, the virtual stop position setting unit 194 sets the virtual stop position SP at a position on the own lane L1 where the lane change cost is the smallest, that is, a position where the suitability of the lane change is high, as shown in FIG. 6(A).

Returning to FIG. 5, the object detection unit 112, which is one of the sensors 11 in FIG. 1, detects moving objects, such as automobiles (other vehicles) other than the host vehicle, traveling around the host vehicle V1 using a side radar or the like. It then detects traveling information such as the position, attitude, speed, and yaw rate of these moving objects relative to the host vehicle, and outputs the detection results to the target vehicle identification unit 113. The vehicle state acquisition unit 114 detects traveling information such as the attitude, speed, and yaw rate of the host vehicle V1, and outputs the detection results to the target vehicle identification unit 113.

When the vehicle V1 reaches the lane change section LC, the target vehicle identification unit 113 identifies a target vehicle for the vehicle V1 to enter behind when the vehicle V1 executes a lane change from the travel information of the moving object traveling around the vehicle V1 acquired from the object detection unit 112 and the travel information of the vehicle V1 acquired from the vehicle state acquisition unit 114. Specifically, as shown in FIG. 6B, the target vehicle is the other vehicle V2 traveling parallel to the vehicle V1 in the target lane L2 or the other vehicle V3 traveling behind the vehicle V1, the other vehicle V2 having a vehicle distance D between the other vehicle V2 and the rear vehicle of a predetermined value or more. The predetermined value of the vehicle distance D is not particularly limited, but is at least a distance longer than the total length of the vehicle V1 and allowing the vehicle V1 to enter and complete the lane change. The target vehicle identification unit 113 outputs the travel information of the identified target vehicle V2 to the lane change execution determination unit 192.

The lane change execution determination unit 192 calculates the possibility that the host vehicle V1 will interfere with the target vehicle V2 and the other vehicle V3 based on the relative positions and relative speeds of the target vehicle V2 identified by the target vehicle identification unit 113, the other vehicle V3 detected by the object detection unit 112, and the host vehicle V1 acquired by the vehicle state acquisition unit 114. If the possibility that the host vehicle V1 will interfere with the target vehicle V2 and the other vehicle V3 is lower than a predetermined threshold, it is determined that the host vehicle V1 will be able to complete the lane change before reaching the virtual stop position SP.

When it is determined that the host vehicle V1 can complete the lane change, as shown in FIG. 8, the lane change execution determination unit 192 controls the virtual stop position release unit 195 to release the setting of the virtual stop position SP, and then controls the actuator of the drive control unit 18 to cause the host vehicle V1 to enter the target lane L2 from the host lane L1, thereby executing the lane change. Similarly, when the object detection unit 112 does not detect a moving object (another vehicle) traveling around the host vehicle V1, the setting of the virtual stop position SP is released, and the actuator of the drive control unit 18 is controlled to cause the host vehicle V1 to enter the target lane L2 from the host lane L1, thereby executing the lane change. Note that the virtual stop position release unit 195 is not an essential component of the present invention, and may be omitted as necessary.

On the other hand, if it is determined that the possibility of the host vehicle V1 interfering with the target vehicle V2 and the other vehicle V3 is higher than a predetermined threshold and that the current deceleration will not allow the host vehicle V1 to complete the lane change before reaching the virtual stop position SP, the lane change execution determination unit 192 calculates the deceleration required for the host vehicle V1 to complete the lane change. FIG. 9 is a plan view (upper figure) showing an example of processing executed by the lane change execution determination unit 192 and the deceleration selection unit 196, and a graph (lower figure) showing the host vehicle's deceleration. This is a driving scene in which the host vehicle V1 traveling in the host lane L1 enters behind the target vehicle V2 traveling in the target lane L2 and attempts to perform a lane change.

In the graph corresponding to the deceleration of the host vehicle V1 shown in FIG. 9 (lower diagram), the vertical axis represents the speed of the host vehicle V1, Vh1 is the speed profile at which the host vehicle V1 stops at the virtual stop position SP, and Vh2 and Vh3 are the speed profiles when the host vehicle V1 decelerates in accordance with the deceleration of the target vehicle V2. The lane change prohibited vehicle speed is a predetermined vehicle speed, and is not particularly limited, but may be, for example, 20 km/h. The horizontal axis of the graph represents the position of the host vehicle V1 in the lane change section LC, P1 is the position at which the host vehicle V1 starts to enter the lane change section LC, P2 is the position at which the host vehicle V1 and the target vehicle V2 run side by side, P3 is the virtual stop position SP of the host vehicle V1, and P4 is the position of the stop line at the intersection that is the front end of the lane change section LC.

When the vehicle V1a reaches the lane change section LC, it starts to decelerate at P1 in order to enter behind the target vehicle V2a. This deceleration is the initial value of the deceleration that has been set in advance. As the vehicle V1 continues to decelerate, the vehicle V1b and the target vehicle V2b will be traveling side by side at P2. At this point, as an intersection is approaching in the direction of travel, if the target vehicle V2b also starts to decelerate, the vehicle V1c and the target vehicle V2c will continue to travel side by side while decelerating from each other.

Therefore, if the host vehicle V1b executes a speed profile Vh2 that further decelerates from the initial value in accordance with the deceleration of the target vehicle V2b in order to enter behind the target vehicle V2b, the host vehicle V1 will fall below the lane change prohibited vehicle speed (20 km/h) at a position that is not near an intersection. In this way, if the host vehicle V1 suddenly decelerates, there is a risk that it will impede the traffic flow of following vehicles or that the host vehicle will stop without being able to change lanes. In contrast, if the host vehicle V1 executes a speed profile Vh1 that stops at the virtual stop position SP, the host vehicle V1 can stop at a position P3 that is highly suitable for lane changing, that is, in driving conditions where the host vehicle V1 can easily change lanes or where the host vehicle V1 is unlikely to cause discomfort to following vehicles even if it stops.

The lane change execution determination unit 192 determines whether the vehicle speed of the host vehicle V1 falls below the lane change prohibited vehicle speed (20 km/h) when executing a speed profile Vh2 that further decelerates from the initial value in accordance with the deceleration of the target vehicle V2, and outputs the determination result to the deceleration selection unit 196. If the vehicle speed falls below the lane change prohibited vehicle speed (20 km/h), there is a possibility that the lane change cannot be completed before reaching the virtual stop position SP. Therefore, the lane change execution determination unit 192 outputs to execute a speed profile Vh1 that gives up on entering behind the target vehicle V2 and stops at the virtual stop position SP. If the vehicle speed does not fall below the lane change prohibited vehicle speed (20 km/h), the lane change execution determination unit 192 outputs to execute a speed profile Vh2 that further decelerates from the initial value in accordance with the deceleration of the target vehicle V2 so as to enter behind the target vehicle V2.

When the deceleration selection unit 196 decides to give up on entering behind the target vehicle V2 and execute the speed profile Vh1 for stopping at the virtual stop position SP, it controls the actuator of the drive control device 18 to re-accelerate the host vehicle V1 (speed profile Vh3). Then, after controlling the deceleration to the speed profile Vh1 for stopping at the virtual stop position SP, it stops the host vehicle V1 at the virtual stop position SP as shown in FIG. 7(A). When the lane change execution determination unit 192 determines that the target vehicle V2 passes to the side of the virtual stop position SP and the possibility of the host vehicle V1 interfering with the target vehicle V2 and the other vehicle V3 is lower than a predetermined threshold as shown in FIG. 7(B), it controls the actuator of the drive control device 18 to cause the host vehicle V1 to enter the target lane L2 from the target lane L1 and execute a lane change.

On the other hand, when executing the speed profile Vh2 that further decelerates from the initial value in accordance with the deceleration of the target vehicle V2, the deceleration selection unit 196 continues decelerating the host vehicle V1 to enter behind the target vehicle V2. Then, when the lane change execution determination unit 192 determines that the possibility of the host vehicle V1 interfering with the target vehicle V2 or the other vehicle V3 is lower than a predetermined threshold, it controls the virtual stop position release unit 195 to release the setting of the virtual stop position SP, and then controls the actuator of the drive control device 18 to cause the host vehicle V1 to enter the target lane L2 from the host lane L1, thereby executing the lane change. Note that in this embodiment, it is determined whether the vehicle speed of the host vehicle V1 falls below the lane change prohibited vehicle speed (20 km/h) at the position P2 shown in FIG. 9, but this determination may be made at any of the positions P1 to P4 in the lane change section LC, and this determination may be repeatedly performed at a predetermined interval.

Next, the calculation process of the lane change cost in the cost setting unit 193 of this embodiment will be described with reference to Figs. 10(A) to 14(B). The lane change cost calculated by the cost setting unit 193 is output to the virtual stop position setting unit 194, and the virtual stop position SP of the host vehicle V1 is set to the position where the lane change cost is minimum. Figs. 10(A) to (D) and Figs. 11(A) to (C) are plan views showing the driving pattern variables in the lane change section LC and graphs showing examples of the lane change costs. Fig. 12 shows examples of the driving patterns and variables stored in the cost setting unit 193. Figs. 13(A) and (B) and Figs. 14(A) and (B) are plan views showing examples of driving scenes to which the driving pattern variables are applied.

First, the cost setting unit 193 sets an initial cost for a position at a predetermined distance from the front end of the lane change section LC so that the lane change cost is minimized. The position at the predetermined distance for which the initial cost is set is not particularly limited, but is a position where lane change suitability is high and suitable for the host vehicle V1 to start entering the target lane L2. For example, as shown in FIG. 10(A), the lane boundary line of the host lane L1 and the target lane L2 is used as a reference, and the lane boundary line changes from a dashed line to a solid line (for example, 30 m before the stop line of the intersection). The position where the lane boundary line changes from a dashed line to a solid line is usually a position where a vehicle stops to change lanes, so it is easy to execute a lane change and is unlikely to cause discomfort to following vehicles even if the host vehicle V1 stops, so the suitability for lane change is high. In this way, the initial cost is set for a position at a predetermined distance where lane change suitability is high so that the lane change cost is minimized.

Next, the cost setting unit 193 updates the value of the lane change cost using the driving pattern variable in order to calculate the lane change cost according to the actual driving situation of the vehicle V1. As shown in FIG. 12, the driving pattern variable is a variable corresponding to the driving pattern that is stored in advance in the cost setting unit 193. This is applied to the current driving situation of the vehicle V1 determined from the driving information of moving objects driving around the vehicle V1 acquired from the object detection unit 112, the driving information of the vehicle V1 acquired from the vehicle state acquisition unit 114, and the driving environment of the vehicle V1, to set the driving pattern variable. The driving environment of the vehicle V1 reflects stationary object information including road markings and parked vehicles around the vehicle V1 detected by the stationary structure detection unit 115, and information on the traffic light TL ahead of the lane change section LC detected by the signal recognition unit 116.

As shown in FIG. 10(A), the cost setting unit 193 initializes the driving scene "30 m before the stop line of the intersection" for which the initial cost of lane change cost is set as driving pattern variable 0. When the driving pattern variable is 0, the position where the lane change cost is smallest is "30 m before the stop line of the intersection". This position is set as the initial setting position IP. Note that in this embodiment, the driving pattern variable is a consecutive integer from 0 to 6, and is reflected in the value of the lane change cost in an additive manner, but the driving pattern variable may be any discrete value or negative number, or may be reflected in the value of the lane change cost in a subtractive manner.

The driving pattern variables shown in Figures 10(B) to (D) are driving patterns in which the position with the smallest lane change cost is closer to the initial setting position IP in the direction of travel of the host vehicle V1. Therefore, the virtual stop position SP is set even closer to the vehicle than "30 m from the stop line of the intersection" for which the initial cost is set. Figure 13(A) is a driving scene corresponding to the driving pattern variables in Figures 10(B) and (C). This shows a driving scene in which the vehicle speed of another vehicle V2 traveling in the target lane L2 is slower than the vehicle speed of the host vehicle V1.

If the vehicle speed of the other vehicle V2 is slower than that of the own vehicle V1 due to congestion in the target lane L2, it becomes more difficult to change lanes as it moves further back from the initial setting position IP. In other words, the possibility of executing a lane change increases as it moves closer to the front side from the initial setting position IP. Therefore, the lane change cost is added to the cost setting ranges VR1 and VR2, and the driving pattern variable is set so that the value of the lane change cost on the front side from the initial setting position IP becomes larger. At this time, if the traffic light TL ahead of the lane change section LC detected by the signal recognition unit 116 is a red light SR, the vehicle speed of the other vehicle V2 becomes even slower, and it becomes more difficult to change lanes as the own vehicle V1 moves closer to the back. Therefore, it is better to set the virtual stop position SP further forward than in the case of a green light SG. Therefore, when the traffic light TL is green SG, the lane change cost is set to a large value up to the cost setting range VR1, which is defined as driving pattern variable 1 (see FIG. 10(B)), and when the traffic light TL is red SR, the lane change cost is set to a large value up to the cost setting range VR2 in addition to the cost setting range VR1, which is defined as driving pattern variable 2 (see FIG. 10(C)).

Figure 13 (B) is a driving scene corresponding to the driving pattern variable in Figure 10 (D). As with Figure 13 (A), this shows a driving scene in which the speed of another vehicle V2 traveling in the target lane L2 is slower than the speed of the host vehicle V1. The difference from Figure 13 (A) is that the rear side of the initial setting position IP is a lane change prohibited section LP. If the stationary structure detection unit 115 detects that the lane change section LC is a lane change prohibited section LP, it is better to set the virtual stop position SP further forward than the above-mentioned driving pattern variables 1 and 2. Therefore, the value of the lane change cost is increased to a cost setting range VR3 in addition to the cost setting ranges VR1 and VR2, which is set as driving pattern variable 3 (see Figure 10 (D)).

In contrast, the driving pattern variables shown in Figures 11(A) to (C) are driving patterns in which the position at which the lane change cost is smallest is on the far side of the initial setting position IP in the traveling direction of the host vehicle V1. Therefore, the virtual stop position SP is set on the far side of the "30 m before the stop line of the intersection" where the initial cost is set. Figure 14(A) is a driving scene corresponding to the driving pattern variables in Figures 11(A) and (B). It shows a driving scene in which the vehicle speed of another vehicle V2 traveling on the target lane L2 is faster than the vehicle speed of the host vehicle V1.

In this case, unlike the driving scenes in Figures 13(A) and 13(B) described above, the vehicle traveling on the target lane L2 is likely to be traveling smoothly, and there is a possibility that the vehicle can change lanes even if it is further back than the initial setting position IP. Therefore, in the cost setting ranges VR4 and VR5, the lane change cost is added to the near side, and a driving pattern variable is set in which the lane change cost decreases as it goes further back from the initial setting position IP. At this time, if the traffic light TL in front of the lane change section LC detected by the signal recognition unit 116 is green SG, the vehicle speed of the other vehicle V2 becomes even faster, and there is a high possibility that the vehicle V1 can change lanes even if it moves further back. Therefore, it is better to set the virtual stop position SP further back than in the case of a red light SR. Therefore, when the traffic light TL is a red light SR, the lane change cost value gradually decreases to the cost setting range VR4, which is defined as driving pattern variable 4 (see FIG. 11(A)), and when the traffic light TL is a green light SG, the lane change cost value gradually decreases to the cost setting range VR5 in addition to the cost setting range VR4, which is defined as driving pattern variable 5 (see FIG. 11(B)).

Note that even if the speed of the other vehicle V2 traveling in the target lane L2 is faster than the speed of the host vehicle V1, if the absolute value of the vehicle speed difference is equal to or greater than a predetermined value, it is not necessary to set the virtual stop position SP further back than "30 m from the stop line of the intersection." In this case, since there is no need to update the driving pattern variable, the driving pattern variable remains initialized at 0.

Figure 14 (B) is a driving scene corresponding to the driving pattern variable in Figure 11 (C). As with Figure 14 (A), a driving scene is shown in which the vehicle speed of another vehicle V2 traveling in the target lane L2 is faster than the vehicle speed of the host vehicle V1. The difference from Figure 14 (A) is that a stationary object (parked vehicle PV) is present in the target lane L2. When the object detection unit 112 detects a parked vehicle PV in the target lane L2, it is better to set the virtual stop position SP behind the front end of the parked vehicle PV. This is because if the virtual stop position SP is set in front of the parked vehicle PV, the host vehicle V1 must repeatedly change lanes. Therefore, the lane change cost is added to the entire cost setting range VR6, and the value of the lane change cost is set to be larger than that of other driving scenes, which is set as driving pattern variable 6 (see Figure 11 (C)).

In this way, the driving pattern variable is set according to the actual driving conditions of the host vehicle V1. The cost setting unit 193 calculates the value of the lane change cost in the lane change section LC based on the driving pattern variable, and outputs it to the virtual stop position setting unit 194. If the driving pattern variable is 0, there is no need to calculate the lane change cost in the lane change section LC, so the initial cost value is output as is to the virtual stop position setting unit 194. Then, as described above, the virtual stop position setting unit 194 sets the virtual stop position SP of the host vehicle V1 to a position on the host lane L1 where the lane change cost is minimum.

<Lane change control processing>
Next, the lane change control process according to this embodiment will be described with reference to Fig. 15 and Fig. 16. Fig. 15 is a flowchart showing an example of the lane change control process executed by the control device 19 of this embodiment. Fig. 16 shows an example of a subroutine of step S5 shown in Fig. 15.

The lane change control process described below is executed at a predetermined time interval by the control device 19. In addition, 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 vehicle's driving position in the width direction so that the vehicle drives within the lane at a speed set by the driver.

First, in step S1, a destination is set based on information acquired from the destination setting unit 151, and then in step S2, a driving route of the host vehicle V1 to the destination is calculated. Next, in step S3, a point on the driving route of the host vehicle V1 where a lane change is required is detected, and a lane change section LC is identified.

In step S4, the lane change section identification unit 191 determines whether the host vehicle V1 has reached the lane change section LC. Step S4 is repeated within a predetermined time until it is determined that the host vehicle V1 has reached the lane change section LC. In contrast, if it is determined that the host vehicle V1 has reached the lane change section LC, the process proceeds to step S5. In step S5, a virtual stop position SP for stopping the host vehicle V1 is set on the host lane L1 in the lane change section LC.

Next, in step S6, it is detected whether or not there is another vehicle traveling on the target lane L2. If there is no other vehicle traveling on the target lane L2, the process proceeds to step S10. On the other hand, if there is another vehicle traveling on the target lane L2, the process proceeds to step S7, where a target vehicle V2 that can enter behind the host vehicle V1 when the host vehicle V1 executes a lane change is identified, and the process proceeds to step S8.

In step S8, the host vehicle V1 starts decelerating at the initial deceleration value in order to enter behind the target vehicle V2. In the following step S9, it is determined whether the host vehicle V1 can complete the lane change before reaching the virtual stop position SP. If it is determined that the lane change can be completed before reaching the virtual stop position SP, the process proceeds to step S10. On the other hand, if it is determined that the lane change cannot be completed before reaching the virtual stop position SP, the process proceeds to step S12.

If it is determined in step S9 that the initial deceleration value is not sufficient to complete the lane change before the vehicle reaches the virtual stop position SP, the vehicle V1 is further decelerated in step S12. Then, in step S13, it is determined again whether the vehicle V1 can complete the lane change before the vehicle reaches the virtual stop position SP.

If it is determined in step S13 that the lane change can be completed before the vehicle reaches the virtual stop position SP, the process proceeds to step S10. On the other hand, if it is determined that the lane change cannot be completed before the vehicle reaches the virtual stop position SP, the process proceeds to step S14.

In step S14, it is determined whether the host vehicle V1 needs to decelerate to a predetermined speed or below (lane change prohibited vehicle speed) to complete the lane change. If it is determined that the host vehicle V1 needs to decelerate to a predetermined speed or below (lane change prohibited vehicle speed) to complete the lane change, a speed profile that stops the host vehicle at the virtual stop position SP is selected, and the process proceeds to step S15. On the other hand, if it is determined that the host vehicle V1 does not need to decelerate to a predetermined speed or below (lane change prohibited vehicle speed) to complete the lane change, a speed profile that further decelerates the host vehicle V1 from the initial value in accordance with the deceleration of the target vehicle V2 is selected, and the process proceeds to step S10.

If it is determined in step S14 that the vehicle needs to decelerate to a predetermined speed (lane change prohibited vehicle speed) or below to complete the lane change, the host vehicle V1 is accelerated again to execute a speed profile that stops the host vehicle at the virtual stop position SP, and the process proceeds to step S16.

In step S16, it is determined again whether the lane change of the host vehicle V1 can be completed before the vehicle reaches the virtual stop position SP. If it is determined that the lane change can be completed before the vehicle reaches the virtual stop position SP, the process proceeds to step S10. If it is determined that the lane change cannot be completed before the vehicle reaches the virtual stop position SP, the process proceeds to step S17, where the host vehicle V1 is stopped at the virtual stop position SP, and the process proceeds to step S18.

In the next step S18, it is determined whether the host vehicle V1 can enter the target lane L2. If the possibility of the host vehicle V1 interfering with the target vehicle V2 traveling on the target lane L2 or other moving objects (other vehicles V3) is lower than a predetermined threshold, it is determined that the host vehicle V1 can enter the target lane L2, and the process proceeds to step S10. On the other hand, if the possibility of the host vehicle V1 interfering with the target vehicle V2 traveling on the target lane L2 or other moving objects (other vehicles V3) is higher than a predetermined threshold, it is determined that the host vehicle V1 cannot enter the target lane L2, and the process returns to step S17, and the subsequent processes are repeated.

If the result of the judgment in step S6 is that there is no other vehicle traveling on the target lane L2, if the result of the judgment in step S13 is that the lane change can be completed before the virtual stop position SP is reached, if the result of the judgment in step S14 is that it is not necessary to decelerate to a predetermined speed or below (lane change prohibited vehicle speed) to complete the lane change, if the result of the judgment in step S16 is that the lane change can be completed before the virtual stop position SP is reached, or if the result of the judgment in step S18 is that the host vehicle V1 can enter the target lane L2, then the virtual stop position SP is released in step S10. Then, once the host vehicle V1 has entered the target lane L2 in step S11, lane change control is terminated.

In step S5 of FIG. 15, the process shown in FIG. 16 is executed as the execution process of the cost setting unit 193 and the virtual stop position setting unit 194. If it is determined in step S4 that the host vehicle V1 has reached the lane change section LC, in step S501, an initial cost is set so that the lane change cost is minimized for a position a predetermined distance from the front end of the lane change section LC, for example, the position "30 m before the stop line of the intersection" shown in FIG. 10(A).

In the next step S502, the driving scene "30 m before the stop line of the intersection" where the initial cost of the lane change cost is set is initialized as a driving pattern variable 0, and the process proceeds to S503. At this time, the position where the initial cost is set is set as the initial setting position IP.

In step S503, the vehicle state acquisition unit 114 detects the vehicle speed of the host vehicle V1, and the object detection unit 112 detects the vehicle speed of the other vehicle V2 traveling in the target lane L2. In the following step S504, the signal recognition unit 116 acquires information about the traffic light TL ahead of the lane change section LC.

Next, in step S505, the vehicle speed of the host vehicle V1 is compared with the vehicle speed of the other vehicle V2 traveling on the target lane L2. As shown in Figures 13(A) and (B), if the vehicle speed of the other vehicle V2 traveling on the target lane L2 is slower than the vehicle speed of the host vehicle V1, the process proceeds to step S506. On the other hand, as shown in Figures 14(A) and (B), if the vehicle speed of the other vehicle V2 traveling on the target lane L2 is faster than the vehicle speed of the host vehicle V1, the process proceeds to step S512.

If it is determined in step S505 that the speed of the other vehicle V2 traveling in the target lane L2 is slower than the speed of the host vehicle V1, there is a possibility that the vehicles are not traveling smoothly in the target lane L2 due to traffic congestion or other reasons. Therefore, in steps S506 to S507, a driving pattern variable is set to move the virtual stop position SP further forward than the initial setting position IP (30 m before the stop line of the intersection).

In step S506, it is determined whether the traffic light TL ahead of the lane change section LC is a red light SR. If it is determined that the traffic light TL is a red light SR, the process proceeds to step S507. If it is determined that the traffic light TL ahead of the lane change section LC is not a red light SR, the process proceeds to step S508, where the driving pattern variable 1 shown in FIG. 10(B) is set.

If it is determined in step S506 that the traffic light TL is a red signal SR, then in the following step S507, it is determined whether the lane change section LC is a lane change prohibited section LP. If it is determined that the lane change section LC is not a lane change prohibited section LP, in step S08, the driving pattern variable 2 shown in FIG. 10(C) is set. In this case, the position at which the lane change cost is minimum is closer to the front than when driving pattern variable 1 was set. In contrast, if it is determined that the lane change section LP is a lane change prohibited section LP, the process proceeds to step S508, and the driving pattern variable 3 shown in FIG. 10(D) is set to set the position at which the lane change cost is minimum further forward than when driving pattern variable 2 was set.

In contrast, if the result of the judgment in step S505 is that the speed of the other vehicle V2 traveling in the target lane L2 is faster than the speed of the host vehicle V1, it is highly likely that the vehicle is traveling smoothly in the target lane L2. Therefore, in steps S512 to S514, a driving pattern variable is set to move the virtual stop position SP further back than the initial setting position IP (30 m before the stop line of the intersection).

In S512, it is determined whether the absolute value of the vehicle speed difference between the vehicle speed of the host vehicle V1 and the vehicle speed of the other vehicle V2 traveling in the target lane L2 is equal to or less than a predetermined value. If it is determined that the absolute value of the vehicle speed difference is equal to or less than the predetermined value, the process proceeds to step S513. If it is determined that the absolute value of the vehicle speed difference is not equal to or less than the predetermined value, the process proceeds to step S509 with the initialized driving pattern variable set to 0.

If it is determined in step S512 that the absolute value of the vehicle speed difference is equal to or less than the predetermined value, then in step S513, it is determined whether the traffic light TL ahead of the lane change section LC is showing a green light SG. If it is determined that the traffic light TL is showing a green light SG, the process proceeds to step S514. On the other hand, if it is determined that the traffic light TL ahead of the lane change section LC is not showing a green light SG, the process proceeds to step S508, where driving pattern variable 4 shown in FIG. 11 (A) is set.

If it is determined in step S513 that the traffic light TL is green SG, then in the following step S514, it is determined whether or not there is a stationary object (parked vehicle PV) in the target lane L2 of the lane change section LC. If it is determined that there is no stationary object (parked vehicle PV) in the lane change section LC, in step S508, the driving pattern variable 5 shown in FIG. 11(B) is set. In this case, the position at which the lane change cost is minimum is further back than when driving pattern variable 4 is set. In contrast, if it is determined that there is a stationary object (parked vehicle PV), the process proceeds to step S508, and the driving pattern variable 6 shown in FIG. 11(C) is set to set the position at which the lane change cost is minimum further back than the front end of the stationary object (parked vehicle PV).

In this way, in step S509, the lane change cost in the lane change section LC is calculated and updated based on the driving pattern variables set from the actual driving conditions of the vehicle V1. Then, in step S510, a position where the lane change cost is minimized is searched for, and in step S511, the virtual stop position SP is set to the position where the lane change cost is minimized.

In the above embodiment, an example was described in which the present invention was applied to the intersections shown in Figures 6 to 8, but the vehicle driving control method and driving control device of the present invention are not limited to intersections, and can be applied to general driving situations in which the vehicle is autonomously controlled to change lanes, such as merging roads and branching roads.

As described above, according to the vehicle driving control method and driving control device of this embodiment, when the host vehicle V1 is driving along a driving route and executes a lane change from the host lane L1 to a target lane L2 by autonomous driving control, a lane change section LC where the lane change is to be executed is identified on the driving route, a virtual stop position SP where the host vehicle V1 is to be stopped is set on the host lane L1 in the lane change section LC, the host vehicle V1 is decelerated and driven to the virtual stop position SP, and it is determined whether the lane change is completed by the time the host vehicle V1 reaches the virtual stop position SP. Then, if it is determined that the lane change is not completed by the time the host vehicle V1 reaches the virtual stop position SP, the host vehicle V1 is stopped at the virtual stop position SP and then the lane change is executed, so that the host vehicle can be prevented from stopping in a state straddling the host lane and another lane.

In addition, according to the vehicle driving control method and driving control device of this embodiment, if it is determined that the lane change will be completed before the vehicle reaches the virtual stop position SP, the lane change is executed, so unnecessary deceleration and stopping control can be suppressed, and the lane change can be executed smoothly.

In addition, according to the vehicle driving control method and driving control device of this embodiment, when determining whether or not a lane change is completed by decelerating the host vehicle V1 to the virtual stop position SP, if the lane change is not completed unless the host vehicle V1 decelerates to a lane change prohibited vehicle speed or below, it is determined that the lane change is not completed, so that a sudden deceleration or stop control of the host vehicle caused by the deceleration of another vehicle can be suppressed.

In addition, according to the vehicle driving control method and driving control device of this embodiment, a lane change cost is calculated as an index of suitability of lane change for the position where lane change is to be performed in the lane change section LC, and the virtual stop position SP is set to the position where the lane change cost is minimum, so that the vehicle can be stopped in a position where lane change is easy to perform and following vehicles are unlikely to feel uncomfortable even if the vehicle stops.

In addition, according to the vehicle driving control method and driving control device of this embodiment, the position at which the lane change cost is minimized is set to a position a predetermined distance forward from the front end of the lane change section LC, so that the vehicle can be stopped at a position that ensures a certain distance for executing a lane change.

In addition, according to the vehicle driving control method and driving control device of this embodiment, the speed of another vehicle V2 traveling in the target lane L2 is detected, and the slower the speed of the other vehicle V2 is than the speed of the host vehicle V1, the closer the position at which the lane change cost is to the front of the traveling direction of the host vehicle V1 with respect to a position a predetermined distance forward from the front end of the lane change section LC, so that the host vehicle can be stopped at a position appropriate to the driving environment of the lane to which the lane is to be changed.

In addition, according to the vehicle driving control method and driving control device of this embodiment, a traffic light TL ahead of the lane change section LC is detected, and when the traffic light TL is red SR, the position at which the lane change cost is the smallest is set forward in the traveling direction of the host vehicle V1 compared to when the traffic light TL is green SG, thereby increasing the possibility that the host vehicle can change lanes.

In addition, according to the vehicle driving control method and driving control device of this embodiment, it is detected whether the lane change section LC is a lane change prohibited section LP, and if it is, the position at which the lane change cost is the smallest is set closer to the traveling direction of the host vehicle V1 than when it is not a lane change prohibited section LP, thereby further increasing the possibility that the host vehicle can change lanes.

In addition, according to the vehicle driving control method and driving control device of this embodiment, the speed of another vehicle V2 traveling in the target lane L2 is detected, and the faster the speed of the other vehicle V2 is than the speed of the host vehicle V1, the further in the traveling direction of the host vehicle V1 is set relative to a position a predetermined distance forward from the front end of the lane change section LC, so that the host vehicle can be stopped at a position appropriate to the driving environment of the lane to which the lane is to be changed.

In addition, according to the vehicle driving control method and driving control device of this embodiment, a traffic light TL ahead of the lane change section LC is detected, and when the traffic light TL is green SG, the position at which the lane change cost is the smallest is set to the farther side in the traveling direction of the host vehicle V1 compared to when the traffic light TL is red SR, thereby increasing the possibility that the host vehicle can change lanes.

In addition, according to the vehicle driving control method and driving control device of this embodiment, a stationary object on the target lane L2 is detected, and when a stationary object is detected, the position at which the lane change cost is minimized is set behind the stationary object in the traveling direction of the host vehicle V1, thereby preventing unnecessary repeated lane changes.

REFERENCE SIGNS LIST 1...cruising control device 11...sensor 12...own 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...own vehicle V2, V3...other vehicles L1...own lane L2...target lane LC...lane change section LP...lane change prohibited section SP...virtual stop position IP...initial setting position TL...traffic light PV...parked vehicle VR1, VR2, VR3, VR4, VR5, VR6...cost setting range

Claims (11)

A vehicle driving control method for executing lane change from a current vehicle lane to a target lane by autonomous driving control while the vehicle is traveling along a driving route,
Identifying a lane change section on the travel route where the lane change is to be performed;
Calculating a lane change cost as an index of suitability of the lane change for a position where the lane change is to be performed in the lane change section;
a virtual stop position for stopping the vehicle is set at a position on the vehicle's own lane in the lane change section where the lane change cost is minimized ;
The vehicle is decelerated and driven to the virtual stop position.
determining whether the lane change will be completed by the time the vehicle reaches the virtual stop position;
A vehicle driving control method, in which, if it is determined that the lane change will not be completed by the time the vehicle reaches the virtual stop position, the vehicle is stopped at the virtual stop position and then the lane change is executed. The vehicle driving control method according to claim 1, which executes the lane change if it is determined that the lane change is completed before the vehicle reaches the virtual stop position. The vehicle travel control method according to claim 1 or 2, in which, when determining whether the lane change is completed by decelerating the vehicle to the virtual stop position, if the lane change is not completed unless the vehicle decelerates to a predetermined speed or less, it is determined that the lane change is not completed. 4. The vehicle travel control method according to claim 1, wherein the position at which the lane change cost is minimized is set at a position a predetermined distance forward from a front end of the lane change section. Detect the speed of other vehicles traveling in the lane you are changing lanes into,
A vehicle driving control method according to any one of claims 1 to 4, wherein the position at which the lane change cost is minimized is set closer to the front of the vehicle in the traveling direction than a position at a predetermined distance forward from the front end of the lane change section, the slower the speed of the other vehicle is compared to the speed of the host vehicle. Detecting a traffic light ahead of the lane change section;
6. A vehicle driving control method according to claim 5 , wherein when the traffic light is red, the position at which the lane change cost is smallest is set closer to the vehicle in the traveling direction than when the traffic light is green. Detecting whether the lane change section is a lane change prohibited section;
A vehicle driving control method as described in claim 5 or 6, wherein when the lane change is prohibited in a section, the position where the lane change cost is smallest is set closer to the vehicle's direction of travel than when the lane change is not prohibited in a section. Detect the speed of other vehicles traveling in the lane you are changing lanes into,
A vehicle driving control method according to any one of claims 1 to 7, wherein the position at which the lane change cost is minimized is set further back in the direction of travel of the vehicle than a position at a predetermined distance forward from the front end of the lane change section, the faster the speed of the other vehicle is compared to the speed of the host vehicle. Detecting a traffic light ahead of the lane change section;
9. The vehicle driving control method according to claim 8 , wherein when the traffic light is green, the position at which the lane change cost is smallest is set to be further back in the traveling direction of the host vehicle than when the traffic light is red. Detecting a stationary object on the lane to which the vehicle is to change lanes;
10. The vehicle travel control method according to claim 8, wherein, when a stationary object is detected, the position at which the lane change cost is minimized is set to a position behind the stationary object in the traveling direction of the host vehicle. A vehicle driving control device including a processor for executing lane change from a current lane to a target lane by autonomous driving control while the vehicle is traveling along a driving route,
The processor,
Identifying a lane change section on the travel route where the lane change is to be performed;
Calculating a lane change cost as an index of suitability of the lane change for a position where the lane change is to be performed in the lane change section;
a virtual stop position for stopping the vehicle is set at a position on the vehicle's own lane in the lane change section where the lane change cost is minimized ;
The vehicle is decelerated and driven to the virtual stop position.
determining whether the lane change will be completed by the time the vehicle reaches the virtual stop position;
When it is determined that the lane change will not be completed by the time the vehicle reaches the virtual stop position, the vehicle driving control device stops the vehicle at the virtual stop position and then executes the lane change.

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