Vehicle control system

Abstract

Vehicle control system (100) attached to a host vehicle (1), the vehicle control system comprising: a vehicle detection unit (32) configured to detect a rear-side vehicle in a rear area of ​​the host vehicle, wherein the rear-side vehicle is one of nearby vehicles traveling in a second lane adjacent to the first lane in which the host vehicle is traveling; a residual distance detection unit (41) configured to detect a residual distance from a current position of the host vehicle to a position at which the host vehicle completes a lane change; a lane-change possibility determination unit (30) configured to determine, based on information acquired by the vehicle detection unit, whether a lane change is possible; and a vehicle control unit (40) configured to control the steering of the host vehicle in such a way that a position of the host vehicle in the vehicle width direction becomes a position that is closer to the second lane than a position when the remaining distance is longer than or equal to the first determination distance.

Description

Background of the invention 1. Technical field of the invention

[0001] The invention relates to a vehicle control system. 2. Description of the closest prior art

[0002] JP 2016-132421 A describes a technique related to a system that performs automated vehicle propulsion control such that the vehicle changes to a target lane using automated propulsion. If a host vehicle cannot change to a target lane using automated propulsion because other vehicles are traveling in the target lane or for other reasons, this technique controls the host vehicle to stop at a change point in a lane oriented toward the lane boundary between the lane and the target lane. Summary of the invention

[0003] If the host vehicle cannot change into the target lane using automated driving, the host vehicle is controlled to stop in the lane using the technology known from JP 2016-132421 A. In this case, the system assistance for automated driving is interrupted, requiring a driver of the host vehicle to manually assume control of the host vehicle. As described above, the technology known from JP 2016-132421 A still offers room for improvement to complete a lane change as far as possible using automated driving.

[0004] The invention provides a vehicle control system that improves the ability to complete a lane change using automated propulsion.

[0005] One aspect of the invention relates to a vehicle control system mounted on a host vehicle, the vehicle control system including: a vehicle detection unit configured to detect a rear side vehicle in a rearward area of ​​the host vehicle, the rear side vehicle being one of nearby vehicles traveling in a second lane adjacent to the first lane in which the host vehicle is traveling; a remaining distance detection unit configured to detect a remaining distance from a current position of the host vehicle to a position at which the host vehicle completes a lane change; a lane change possibility determination unit configured to determine whether the lane change is possible based on information detected by the vehicle detection unit;and a vehicle control unit configured to, when the lane change possibility determination unit determines that the lane change is not possible and the remaining distance is shorter than a first determination distance, control the steering of the host vehicle so that a position of the host vehicle in the vehicle width direction becomes a position closer to the second lane than a position when the remaining distance is longer than or equal to the first determination distance.

[0006] In the above aspect, the vehicle detection unit may be configured to detect a front lateral vehicle in a front area of ​​the host vehicle, the front lateral vehicle being one of nearby vehicles traveling on the second lane; and the vehicle control unit may be configured to control a speed of the host vehicle so as to reduce an inter-vehicle distance between the host vehicle and the front lateral vehicle when all of conditions i) to iii) are satisfied: i) the lane change possibility determination unit determines that the lane change is not possible, ii) there is a front lateral vehicle and a rear lateral vehicle, and iii) the remaining distance is shorter than a predetermined second determination distance.

[0007] In the above aspect, the vehicle control unit may be configured to control the speed of the host vehicle so that the inter-vehicle distance between the host vehicle and the front lateral vehicle increases when the conditions iv) to vi) are all satisfied: iv) the lane change possibility determining unit determines that the lane change is not possible, v) there is the front lateral vehicle, and vi) there is no rear lateral vehicle.

[0008] In the above aspect, the vehicle control unit may be configured to control the speed of the host vehicle so that the inter-vehicle distance between the host vehicle and the rear side vehicle increases when the conditions vii) to ix) are all satisfied: vii) the lane change possibility determining unit determines that the lane change is not possible, viii) there is the rear side vehicle, and ix) there is no front side vehicle.

[0009] In the above aspect, the lane change possibility determining unit may be configured to calculate a time until collision with a nearby vehicle that is one of nearby vehicles traveling on the second lane, and determine that the lane change is possible when the time until collision is longer than a predetermined determination time.

[0010] By monitoring a remaining distance to a position where the vehicle completes a lane change, the vehicle control system according to the aspect of the invention makes it possible to detect a situation in which the vehicle requires the right-of-way from the rear-side vehicle for the vehicle to change lanes. When the remaining distance becomes shorter than the first determination distance, the position of the vehicle in the vehicle width direction is brought closer to the adjacent lane. Thus, it is possible to notify the rear-side vehicle of the vehicle's lane change intention and effect the right-of-way. Thus, the possibility of completing a lane change with automated driving is improved.

[0011] According to the aspect of the invention, when the remaining distance becomes shorter than the second determination distance, the inter-vehicle distance between the vehicle and the front lateral vehicle is reduced. Thus, it is possible to notify the rear lateral vehicle of the vehicle's lane change intention and initiate the right-of-way. This makes it possible to complete a lane change with automated driving.

[0012] According to the aspect of the invention, when lane changing is not possible and there is a front-side vehicle and no rear-side vehicle, the inter-vehicle distance between the vehicle and the front-side vehicle is increased. Thus, the vehicle can quickly enter a lane changing state, thereby improving the ability to complete a lane change with automated driving.

[0013] According to the aspect of the invention, when lane changing is not possible and there is a rear side vehicle and no front side vehicle, the inter-vehicle distance between the vehicle and the front side vehicle is increased. Thus, the vehicle can quickly enter a lane changing state, thereby improving the ability to complete a lane change with automated driving.

[0014] The determination of whether a lane change is possible can be made by comparing the time until a collision with a surrounding vehicle traveling in the second lane with the predetermined determination time. This makes it possible to accurately determine whether a lane change is possible.

[0015] In this way, according to the aspect of the invention, it is possible to provide a vehicle control system that improves the ability to complete a lane change with automated driving. Short description of the characters

[0016] Functions, advantages as well as technical and industrial significance of embodiments of the invention are described below with reference to the accompanying figures in which numerals indicate elements, wherein: Fig. 1 is a schematic view of a diagram showing lane change control of a vehicle control system according to a first embodiment; Fig. 2 is a conceptual view of a diagram showing lane change control of a vehicle control system according to the first embodiment; Fig. 3 is a diagram showing the schematic configuration of the vehicle control system of the first embodiment; Fig. 4 is a flowchart showing a procedure of lane change control executed in the first embodiment; Fig. 5 is a conceptual view of a diagram showing lane change control of a vehicle control system according to a second embodiment; Fig. 6 is a flowchart showing a part of a flow of the lane change control executed in the second embodiment; and Fig. 7 is a flowchart showing the other part of a flow of the lane change control executed in the second embodiment. Detailed description of the implementation examples

[0017] Embodiments of the invention are described below with reference to the accompanying figures. When reference is made to the number, number, quantity, reference, amount, or selection of each component in the following embodiments, the invention is not limited thereto unless otherwise stated or apparently determined so fundamentally. The structures, steps, and the like described in the following embodiments are not always indispensable to the invention unless otherwise stated or apparently determined so fundamentally. 1. Embodiment 1-1. Overview of a lane change control of a vehicle control system

[0018] Fig. 1 is a schematic view of a diagram showing lane change control of the vehicle control system according to a first embodiment. The vehicle control system is mounted on a vehicle and executes lane change control to perform lane change with automated driving. In the following description, the vehicle equipped with the vehicle control system is referred to as vehicle (1), and vehicles traveling around the vehicle (1) are referred to as surrounding vehicles. A lane on which the vehicle (1) is traveling is referred to as a first lane, and among the lanes adjacent to the first lane, a target lane on which the vehicle (1) completes a lane change is referred to as a second lane.Of the surrounding vehicles, a nearest following vehicle traveling in the second lane is referred to as a rear side vehicle (2), and of the surrounding vehicles, the nearest preceding vehicle traveling in the second lane is referred to as a front side vehicle (3).

[0019] When the vehicle control system determines that the vehicle (1) requires a lane change based on a lane plan, the vehicle control system automatically causes the vehicle (1) to perform a lane change from the first lane to the second lane in the lane change control. At this time, the vehicle control system obtains information from the surroundings of the vehicle (1) and determines whether a lane change of the vehicle (1) is possible based on the information from the surroundings. The information from the surroundings includes an inter-vehicle distance and a relative speed to the rear lateral vehicle (2), and an inter-vehicle distance and a relative speed to the front lateral vehicle (3). When the vehicle control system determines that a lane change of the vehicle (1) is possible, the vehicle control system causes the vehicle (1) to perform a lane change to the second lane.On the other hand, if the vehicle control system determines that a lane change of the vehicle (1) is not possible, the vehicle control system does not cause the vehicle (1) to perform a lane change to the second lane and allows the vehicle (1) to continue driving in the first lane. If the vehicle (1) has reached a point where it should complete a lane change, even though the vehicle control system determines that a lane change of the vehicle (1) is not possible, the vehicle control system stops the vehicle (1), terminates the automated drive, and switches to manual drive by the driver.

[0020] The inventors of the subject matter of the application finally became aware of the following concerns regarding the vehicle control system described above. It is difficult for the vehicle (1) to communicate with drivers of surrounding vehicles during automated driving. Therefore, it is difficult for the vehicle (1) to obtain an opportunity to perform a lane change based on the right-of-way of a surrounding vehicle during automated driving, which may reduce the possibility of completing a lane change with automated driving.

[0021] For this reason, the vehicle control system according to the embodiment executes an operation to give way to a surrounding vehicle depending on a remaining distance from a current position of the vehicle (1) to a position at which the vehicle (1) should complete a lane change. Fig. 2 is a conceptual view of a diagram showing lane change control of the vehicle control system according to the first embodiment. As shown in this figure, the vehicle control system brings the traveling path of the vehicle (1) in the first lane close to the second lane. In the following description, a traveling path on which the vehicle (1) travels while maintaining the first lane is referred to as a lane-keeping traveling path, and a traveling path on which the vehicle (1) performs a lane change from the first lane to the second lane is referred to as a lane-change traveling path. A traveling path shifted in the first lane by the vehicle (1) from the lane-keeping traveling path toward the second lane is referred to as a shifted traveling path. When the vehicle (1) travels along such a shifted traveling path, the position of the vehicle (1) in the vehicle width direction approaches the second lane.Such behavior of vehicle (1) expresses a lane change intention to surrounding vehicles. If the rear lateral vehicle yields the right-of-way and decelerates, and in response to the behavior of vehicle (1) traveling along the shifted path, the possibility of maintaining a safe distance for a lane change in front of the rear lateral vehicle (2) is improved. As a result, the possibility of determining that a lane change of vehicle (1) is possible increases.

[0022] When the vehicle (1) travels along the shifted travel path even though there is sufficient remaining distance, the rear-side vehicle (2), which may allow the vehicle (1) to travel ahead, may be urged to decelerate. Forcing a surrounding vehicle to decelerate in this way may hinder smooth traffic, and is therefore undesirable. Therefore, the vehicle control system according to the embodiment causes the vehicle (1) to travel along a travel path depending on a remaining distance to complete a lane change, while largely avoiding causing the rear-side vehicle (2) to yield right of way, such as deceleration. Specifically, when the remaining distance is shorter than a predetermined first determination distance, the vehicle control system causes the vehicle (1) to travel along the shifted travel path.For example, the initial determination distance is set as a low limit for the remaining distance to ensure the ability to complete a lane change while maintaining smooth traffic flow. This makes it possible to improve the ability to complete a lane change with automated driving while reducing the possibility of disrupting smooth traffic flow. 1-2. Example of a vehicle control system configuration:

[0023] Next, an example of the configuration of the vehicle control system that executes the lane change control described above is described. Fig. 3 is a diagram showing the schematic configuration of the vehicle control system of the first embodiment. Fig. The vehicle control system shown in Figure 3 is mounted on the vehicle (1) and performs automated drive control to control the automated drive of the vehicle (1).

[0024] As in Fig. 3, the vehicle control system (100) includes a vehicle electronic control unit ECU (10) mounted on the vehicle (1). The vehicle control system (100) includes a camera (11), a radar (12), an HMI unit (13), a communication device (14), a navigation system (15), and a vehicle status detection sensor (16) connected to the input side of the vehicle ECU (10). The vehicle control system (100) further includes a steering system (52), a drive system (54), and a braking system (56) as a driving system (50) connected to the output side of the vehicle ECU (10).

[0025] The camera (11) includes, for example, a front camera, a right rear camera, and a left rear camera. The front camera captures an image of the area in front of the vehicle (1). The right rear camera captures an image from the area behind the vehicle (1) to the right side of the vehicle (1). The left rear camera captures an image from the area behind the vehicle (1) to the left side of the vehicle (1). The camera (11) functions as an information acquisition unit that acquires information from the environment around the vehicle (1). The images captured by the camera (11) are each transmitted to the vehicle ECU (10) as image data, and each piece of image data is subjected to image processing in the vehicle ECU (10).Environmental information captured by the camera (11) includes, for example, position information of a surrounding vehicle traveling in the area around the vehicle (1), road information such as white line information and traffic signal information, and other information.

[0026] The radar (12) is, for example, a laser radar, a millimeter-wave radar, or other radar. The radar (12) functions as an information acquisition unit that acquires information from the environment around the vehicle (1). The radar (12) transmits laser waves or other waves both forward and backward from the vehicle (1) and receives reflected waves of the waves. Thus, the radar (12) acquires information from the environment around the vehicle (1). Examples of the environmental information acquired by the radar (12) include information on whether there is a surrounding vehicle, information on the distance to the surrounding vehicle, information on the angle (i.e., the relative position) of the surrounding vehicle, information on the speed (relative speed) of the surrounding vehicle, and information on the positions of power poles, buildings, and the like.Components of the information detected by the radar (12) are transmitted each time to the vehicle ECU (19).

[0027] The HMI unit (13) is an interface that provides information to the driver of the vehicle (1) and also receives information from the driver. For example, the HMI unit (13) includes an input device, a display device, and a speaker. Examples of the input device include a touch panel, a keyboard, a switch, and a button. The input device specifically includes an automated driving switch for turning an automated driving function on or off. The driver can use the input device to input information such as a target into the HMI unit. Components of the information input by the driver are transmitted to the vehicle ECU (10) each time.

[0028] The communication device (14) functions as an information acquisition unit that receives environmental information from a roadside device on a road via an antenna provided on the vehicle (1). The roadside device is, for example, a positioning device that transmits traffic congestion information, lane-specific traffic information, regulatory information such as temporary stopping, information about the traffic situation of a blind spot, or other information. The communication device (14) functions as an information acquisition unit that communicates directly or via the relay path (not shown) with a surrounding vehicle in the area around the vehicle (1) via the antenna. Examples of the environmental information acquired by the communication device (14) include information about the position of the surrounding vehicle and information about the speed of the surrounding vehicle.Components of the information received by the communication device (14) are transmitted each time to the vehicle ECU (10).

[0029] The navigation system (15) acquires the current position of the vehicle (1) from a GPS satellite via the antenna and, for example, acquires the vehicle's (1) traveling speed or guides a route to a specified destination using GPS, a speed sensor, a gyroscope, and the like. Map data containing detailed road information is integrated into the navigation system (15). The map data includes, for example, information about the route, the number of lanes, and the lane width of each road. Information about the current position, road information, or other information acquired by the navigation system (15) is transmitted to the vehicle ECU (10) each time.

[0030] The vehicle status detection sensor (16) detects the driving status of the vehicle (1). Examples of the vehicle status detection sensor (16) include a vehicle speed sensor, a lateral acceleration sensor, and a yaw rate sensor. Information detected by the vehicle status detection sensor (16) is transmitted to the vehicle ECU (10).

[0031] The steering system (52) is composed of a steering system and a steering actuator. The steering system (52) automatically controls a steering angle independent of the driver's steering operation. The steering system is a general steering system that changes the direction of the wheels in response to the driver's steering operation. The steering actuator changes the direction of the wheels as automated steering based on a command from a steering control unit (44) (described below) independent of the driver's steering operation.

[0032] The drive system (54) is a drive source of the vehicle (1) and is, for example, an engine. The driving force generated by the drive system (54) is transmitted to the drive wheels via a power transmission path (not shown). A fuel injection amount and timing, a throttle opening of the engine, and the like, which serve as the drive system (54), are controlled by a speed control unit (45) (described below). Thus, the driving force of the vehicle (1) is controlled.

[0033] The braking system (56) is composed of a braking device and a brake actuator. The braking system (56) automatically supplies braking force to the wheels regardless of the driver's braking operation. The braking device is a general-purpose braking device, such as an air brake device, that generates braking force on the front and rear wheels using air pressure in response to the driver's depressing of the brake pedal. The braking actuator, as an automatic brake, generates braking force of a selected magnitude on each wheel based on a command from the speed control unit (45) (described below), independent of the driver's braking operation. 1-3. Description of vehicle ECU functions

[0034] The vehicle control system (100) executes automated drive control to control the automated drive of the vehicle (1). The vehicle control system (100) includes the vehicle electronic control unit ECU (10). The vehicle ECU (10) is a microcomputer that includes an input / output interface, a memory, and a processor. The vehicle ECU (10) receives information from the camera (11), the radar (12), the HMI unit (13), the communication device (14), the navigation system (15), and the vehicle status detection sensor (16), and executes automated drive control based on the received information. Specifically, the vehicle ECU (10) sets a driving plan of the vehicle (1) and controls the driving system (50) so that the vehicle (1) drives in accordance with the driving plan.

[0035] The vehicle ECU (10) executes lane change control in the automated driving control of the vehicle ECU (10). In the lane change control, the vehicle ECU (10) causes the vehicle (1) to change lanes in accordance with the driving plan. The vehicle ECU (10) includes a lane change requirement determination unit (20), a surrounding vehicle detection unit (32), a lane change possibility determination unit (30), and a vehicle control unit (40) as functional blocks for implementing the lane change control or a control related to the lane change control.

[0036] The lane change requirement determination unit (20) includes a lane planning unit (22). The lane planning unit (22) sets a lane plan based on destination information transmitted from the HMI unit (13) and the map information transmitted from the navigation system (15). The lane plan includes scheduled lanes on which the vehicle (1) travels. The lane change requirement determination unit (20) determines whether a lane change is required by the vehicle (1) based on the set lane plan and its own position transmitted from the navigation system (15). The result of the determination as to whether the vehicle (1) needs a lane change is transmitted to the lane change possibility determination unit (30).

[0037] The surrounding vehicle detection unit (32) is a functional block for detecting the status of a surrounding vehicle traveling in the area around the vehicle (1). The surrounding vehicle detection unit (32) acquires information about surrounding vehicles, in particular from the camera (11), the radar (12), the communication device (14), and the navigation system (15), all of which are information acquisition units. Examples of information about surrounding vehicles include whether there is a rear lateral vehicle (2) traveling behind in the second lane, the position and vehicle speed of the rear lateral vehicle (2), whether there is a front lateral vehicle (3) traveling ahead in the second lane, and the position and vehicle speed of the front lateral vehicle (3).The surrounding vehicle detection unit (32) detects the relative distance (L) and the relative speed (V) between the vehicle (1) and the detected surrounding vehicle based on the information about the surrounding vehicle and the current vehicle speed of the vehicle (1) transmitted from the vehicle status detection sensor (16). The detected information about the surrounding vehicle is transmitted to the lane change possibility determination unit (30) and the vehicle control unit (40).

[0038] The lane change possibility determination unit (30) is a functional block that determines whether a lane change is possible when information indicating that the vehicle (1) needs to make a lane change is transmitted from the lane change requirement determination unit (20). The lane change possibility determination unit (30) calculates the time to collision (TTC) between the vehicle (1) and the rear lateral vehicle (2) based on the relative distance L and the relative speed V detected by the surrounding vehicle detection unit (32). If the calculated TTC is greater than or equal to a predetermined determination time, the lane change possibility determination unit (30) determines that a lane change of the vehicle (1) to the second lane is possible. The determined result is transmitted to the vehicle control unit (40).

[0039] The vehicle control unit (40) is a functional block functioning as a vehicle control unit that controls the automated driving of the vehicle (1) based on information transmitted from the lane change requirement determination unit (20), the lane change possibility determination unit (30), and the surrounding vehicle detection unit (32). The vehicle control unit (40) specifically includes a remaining distance detection unit (41), a travel path generation unit (42), a speed generation unit (43), a steering control unit (44), and the speed control unit (45).

[0040] The remaining distance detection unit (41) calculates the remaining distance (X) from the current position of the vehicle (1) to a target position at which a lane change is completed based on the specified lane plan. For example, if the first lane is a merging lane leading to the second lane, the target position may be set to the end of the merging lane where the lane width begins to narrow. Alternatively, the target position may be set to a braking start point to stop the current vehicle speed at the end of the merging lane. The remaining distance detection unit (41) detects the target position based on the surrounding information acquired by the camera (11), the radar (12), and the navigation system (15) as information acquisition units.The remaining distance detection unit (41) detects a distance from the own position, which is transmitted from the navigation system (15), to the target position as a remaining position X. The detected remaining distance (X) is transmitted to the travel path generation unit (42) and the speed generation unit (43).

[0041] The travel path generation unit (42) generates a target travel path of the vehicle (1) based on the information transmitted from the lane change requirement determination unit (20), the lane change possibility determination unit (30), and the remaining distance detection unit (41). For example, if information indicating that the vehicle (1) does not need to change lanes has been transmitted from the lane change requirement determination unit (20), the travel path generation unit (42) generates a lane-keeping travel path. If information indicating that the vehicle (1) needs to change lanes has been transmitted from the lane change requirement determination unit (20), and information indicating that a lane change is possible has been transmitted from the lane change possibility determination unit (30), the travel path generation unit (42) generates a lane change travel path.Furthermore, when information indicating that the vehicle (1) needs to make a lane change has been transmitted from the lane change requirement determination unit (20), and information indicating that lane change is not possible has been transmitted from the lane change possibility determination unit (30), the travel path generation unit (42) generates a relocated travel path based on the remaining distance (X) transmitted from the remaining distance acquisition unit (41). A specific process executed by the travel path generation unit (42) will be described in accordance with a flowchart (described below).

[0042] The speed generation unit (43) generates a target speed of the vehicle (1) based on information transmitted from the travel path generation unit (42), the surrounding vehicle detection unit (32), the lane change possibility determination unit (30), and the remaining distance detection unit (41). For example, the speed generation unit (43) generates a target speed for implementing the target travel path transmitted from the travel path generation unit (42) while maintaining a safe distance from the surrounding vehicle detected by the surrounding vehicle detection unit (32). In the following description, the target speed of the vehicle (1) traveling on the lane-keeping travel path is referred to as the lane-keeping speed, and the target speed of the vehicle (1) traveling on the lane-changing travel path is referred to as the lane-changing speed.

[0043] The steering control unit (44) determines the degree of actuation of the steering system (52) for achieving the target travel path. The speed control unit (45) determines the degree of actuation of the drive system (54) and braking system (56) for achieving the target speed. 1-4. Specific process of lane change control

[0044] Next, the specific process of the lane change control executed by the lane change controller (100) of the first embodiment having the above-described configuration will be described with reference to the flowchart. Fig. Fig. 4 is a flowchart showing the procedure of the lane change control executed in the first embodiment. Fig. 4 is repeatedly executed by the vehicle ECU (10) at predetermined control intervals (for example, intervals of 0.1 seconds) during automated driving of the vehicle (1).

[0045] If the Fig. 4 is started, the lane change requirement determination unit (20) of the vehicle ECU (10) first determines whether the vehicle (1) needs to make a lane change based on a set plan and its own position transmitted from the navigation system (15) (step S100). If the lane change requirement determination unit (20) determines that the vehicle (1) does not need to make a lane change, the vehicle ECU (10) generates a lane-keeping travel path as a result (step S102).

[0046] When the lane-keeping travel path is generated in step S102, the speed generation unit (43) of the vehicle control unit (40) generates a lane-keeping speed (step S104). The speed generation unit (43) generates a speed as the lane-keeping speed to cause the vehicle (1) to travel along the lane-keeping travel path transmitted from the travel path generation unit (42) while maintaining a safe distance from the surrounding vehicle detected by the surrounding vehicle detection unit (32).

[0047] On the other hand, if the lane change requirement determination unit (20) determines in step S102 that the vehicle (1) needs to make a lane change, the lane change possibility determination unit (30) of the vehicle ECU (10) determines whether a lane change is possible (step S106). If the lane change possibility determination unit (30) determines that a lane change is possible, the vehicle ECU (10) generates a lane change travel path as a result (step S108).

[0048] When the lane change travel path is generated in step S108, the speed generation unit (43) generates a lane change speed (step S110). The speed generation unit (43) generates a speed as the lane change speed to cause the vehicle (1) to travel along the lane change travel path transmitted from the travel path generation unit (42) while maintaining a safe distance from the surrounding vehicle detected by the surrounding vehicle detection unit (32).

[0049] On the other hand, if the lane change possibility determination unit (30) determines that lane change is not possible in the process in step S105, the surrounding vehicle detection unit (32) of the vehicle ECU (10) determines whether there is a rear side vehicle (2) (step S112). If the surrounding vehicle detection unit (32) determines that there is no rear side vehicle (2), the process proceeds to step S102 as a result.

[0050] On the other hand, if the surrounding vehicle detection unit (32) determines in process step S112 that there is a rear lateral vehicle (2), the process proceeds to the next step. In the next step, the vehicle ECU (10) determines whether the remaining distance (X) is shorter than the predetermined first distance (step S114). The vehicle control unit (40) compares the remaining distance (X) detected by the remaining distance detection unit (41) with the first determination distance. The first determination distance is set, for example, as a low limit for the remaining distance in order to obtain a possibility of completing a lane change, primarily from the perspective of maintaining smooth traffic. If the vehicle ECU (10) determines that the remaining distance (X) is not shorter than the first determination distance, the process proceeds to step S102.

[0051] On the other hand, if the vehicle ECU (10) determines in process step S114 that the remaining distance (X) is shorter than the first determination distance, the process proceeds to the next step. In the next step, the travel path generation unit (42) of the vehicle control unit (40) calculates the amount of displacement of the travel path (step S116). The travel path generation unit (42) calculates the amount of displacement of the lane-keeping travel path to bring the position of the vehicle (1) closer to the second lane in the vehicle width direction. The travel path generation unit (42) calculates, for example, the amount of displacement that brings the vehicle (1) within the first lane closer to the second lane based on map information and its own position transmitted from the navigation system (15), the white line information transmitted from the camera (11), and other information.Subsequently, the travel path generation unit (42) generates a relocated travel path based on the calculated amount of displacement (step S118). Once the relocated travel path is generated in step S118, the process proceeds to step S104.

[0052] When process step S104 or S110 is executed, the vehicle ECU (10) consequently controls the steering and speed of the vehicle (1) (step S120). The steering control unit (44) determines the degree of operation of the steering system (52) for achieving the target travel path and controls the steering system (52). In addition, the speed control unit (45) determines the degree of operation of the drive system (54) and the brake system (56) for achieving the target speed and controls the drive system (54) and the brake system (56).

[0053] With such a control, the possibility of completing a lane change with automated drive is improved because the shifted travel path is generated depending on the remaining distance (X). 2. Example

[0054] Next, a vehicle control system of a second embodiment will be described. 2-1. Configuration of a vehicle control system according to a second embodiment

[0055] The configuration of the vehicle control system according to a second embodiment is the same as that of the vehicle control system (100) of the Fig. 3. Therefore, a detailed description of the vehicle control system according to the second embodiment will be omitted. 2-2. Characteristic function of the vehicle control system according to the second embodiment

[0056] In the vehicle control system (100) of the first embodiment, the vehicle (1) travels along the shifted travel path to cause the rear lateral vehicle (2) to yield the right-of-way. The vehicle control system (100) according to the second embodiment has a characteristic in the operation of causing the rear lateral vehicle (2) to yield the right-of-way by reducing the inter-vehicle distance to the front lateral vehicle (3) when there are both types of vehicles, a front lateral vehicle (3) and a rear lateral vehicle (2).

[0057] Fig. 5 is a conceptual view of a diagram showing lane change control of a vehicle control system according to a second embodiment. As shown in this figure, when there is a rear lateral vehicle (2) and the remaining distance (X) is shorter than the predetermined first determination distance, the vehicle control system (100) controls the steering of the vehicle (1) such that the vehicle (1) travels along the shifted travel path. This operation is similar to the operation of the vehicle control system (100) according to the first embodiment. When there is not only a rear lateral vehicle (2) but also a front lateral vehicle (3), and the remaining distance is shorter than the predetermined second determination distance, the vehicle control system (100) controls the speed of the vehicle (1) such that the inter-vehicle distance to the front lateral vehicle (3) decreases.In the following description, this speed is referred to as the inter-vehicle distance decreasing speed. When the vehicle (1) travels at the inter-vehicle distance decreasing speed, the vehicle (1) can communicate a lane change intention to the rear lateral vehicle (2). If the rear lateral vehicle (2) yields the right-of-way and decelerates in response to such behavior of the vehicle (1), the possibility of maintaining a safe distance for a lane change in front of the rear lateral vehicle (2) is improved. Thus, the possibility of determining that a lane change of the vehicle (1) is possible is also improved.

[0058] When the vehicle (1) travels in such a manner that the inter-vehicle distance to the front lateral vehicle (3) decreases even though there is a sufficient remaining distance (X), the rear lateral vehicle (2), which can allow the vehicle (1) to advance, may be urged to decelerate. Forcing a surrounding vehicle to decelerate in this way may hinder smooth traffic flow, and is therefore undesirable. Therefore, the vehicle control system according to the embodiment travels at a speed depending on a remaining distance to complete a lane change, while largely avoiding causing the rear lateral vehicle (2) to yield and decelerate. Specifically, when the remaining distance is shorter than a predetermined second determination distance, the vehicle control system controls the speed so that the inter-vehicle distance to the front lateral vehicle (3) decreases.For example, the second determination distance is set as a low limit for the remaining distance to maintain the possibility of completing a lane change while prioritizing smooth traffic flow. The second determination distance does not necessarily have the same value as the first determination distance. Thus, it is possible to improve the possibility of completing a lane change with automated driving while reducing the possibility of disrupting smooth traffic flow.

[0059] In the lane change control of the vehicle control system according to the second embodiment, speed control can be performed as described below. When there is a rear side vehicle (2) but no front side vehicle (3), the speed of the vehicle (1) can be controlled so that the inter-vehicle distance to the rear side vehicle (2) increases. In the following description, the speed for maintaining the safe distance between the rear side vehicle (2) and the vehicle (1) is referred to as the rear side distance maintaining speed. When the vehicle (1) travels at the rear side distance maintaining speed, the time required to maintain a safe distance from the rear side vehicle (2) is reduced. Thus, the ability to complete a lane change with automated driving is improved.

[0060] On the other hand, when there is a front lateral vehicle (3) but no rear lateral vehicle (2), the speed of the vehicle (1) can be controlled so that the inter-vehicle distance to the front lateral vehicle (3) increases. In the following description, the speed for maintaining a safe distance between the front lateral vehicle (3) and the vehicle (1) is referred to as the front lateral distance maintaining speed. When the vehicle (1) travels at the front lateral distance maintaining speed, the time it takes to maintain a safe distance from the front lateral vehicle (3) is reduced. Thus, the ability to complete a lane change with automated driving is improved. 2-3. Specific process of lane change control

[0061] Next, the specific process of lane change control executed by the vehicle control system (100) of the second embodiment having the above-described configuration will be described with reference to the flowchart. Fig. 6 and Fig. 7 are flowcharts showing the procedure of the lane change control executed in the second embodiment. A and B in Fig. 6 correspond to A and B in Fig. 7. The Fig. 6 and Fig. The process shown in Fig. 7 is repeatedly executed by the vehicle ECU (10) at predetermined control intervals (for example, intervals of 0.1 seconds) during the automated drive of the vehicle (1).

[0062] In process steps S200 to S210 of the Fig. 6, similar processes as in process steps S100 to S110 of the Fig. 4 is executed. If the lane change possibility determination unit (30) determines in process step S206 that a lane change is not possible, the surrounding vehicle recognition unit (32) subsequently determines whether there is the front side vehicle (3) and no rear side vehicle (2) (step S212). If the determination is affirmative, the vehicle ECU (10) accordingly determines that a safe distance must be maintained to the front and sides of the vehicle (1) while the vehicle (1) continues to travel in the first lane, and then the process proceeds to the next step.

[0063] In the next step, the vehicle ECU (10) generates a lane keeping travel path (step S214). A similar process to that in Fig. Process step S102 shown in Figure 4 is executed. When the lane-keeping travel path is generated in step S214, the speed generation unit (43) of the vehicle control unit (40) generates a front-side distance maintaining speed (step S216). The speed generation unit (43) generates a front-side distance maintaining speed for maintaining the safe distance for a lane change behind a front-side vehicle (3) detected by the surrounding vehicle detection unit (32) while the vehicle (1) is traveling on the lane-keeping travel path. The speed generation unit (43) sets the front-side distance maintaining speed as a speed lower than that of the front-side vehicle (3), so that the inter-vehicle distance to the front-side vehicle (3) increases.

[0064] If the determination is negative, the surrounding vehicle recognition unit (32) determines, as a result of process step S212, whether there is no front side vehicle (3) and a rear side vehicle (2) (step S218). If the determination is positive, the vehicle ECU (10) accordingly determines that a safe distance to the rear and sides of the vehicle (1) must be maintained while the vehicle (1) continues to travel in the first lane, and then the process proceeds to the next step.

[0065] In the next step, the vehicle ECU (10) generates a lane-keeping travel path (step S220). A process similar to that in process step S114 is executed. When the lane-keeping travel path is generated in step S220, the speed generation unit (43) of the vehicle control unit (40) generates a rear-side distance maintenance speed (step S222). The speed generation unit (43) generates a rear-side distance maintenance speed for maintaining the safe distance for a lane change in front of a rear-side vehicle (2) detected by the surrounding vehicle detection unit (32) while the vehicle (1) is traveling on the lane-keeping travel path.The speed generation unit (43) sets the rear lateral distance maintaining speed as a higher speed than that of the rear lateral vehicle (2) so that the inter-vehicle distance to the rear lateral vehicle (2) increases.

[0066] If the determination is negative, the process proceeds to step S224 as a result of process step S218. In process steps S224 to S228, similar process steps as in S114 to S118 are executed. In process step S230, a similar process as in Fig. 4 shown process step S102 is executed.

[0067] When process step S228 or S230 is executed, the vehicle ECU (10) therefore determines whether a remaining distance is shorter than the predetermined second determination distance (step S232). The vehicle control unit (40) compares the remaining distance (X) detected by the remaining distance detection unit (41) with the second determination distance. The second determination distance is set, for example, as a low limit for the remaining distance in order to obtain a possibility of completing a lane change, primarily from the perspective of maintaining smooth traffic. If the vehicle ECU (10) determines that the remaining distance (X) is shorter than the second determination distance, the speed generation unit (43) of the vehicle control unit (40) generates an inter-vehicle distance decreasing speed (step S234).The speed generation unit (43) generates a speed as an inter-vehicle distance reduction speed for reducing the inter-vehicle distance to the front lateral vehicle (3) detected by the surrounding vehicle detection unit (32) while the vehicle (1) is traveling on the lane-keeping travel path. The speed generation unit (43) sets the rear lateral distance maintenance speed as a speed higher than the speed of the front lateral vehicle (3).

[0068] On the other hand, if the vehicle ECU (10) determines that the remaining distance (X) is not shorter than the second determination distance, the vehicle ECU (10) determines in process step S232 that the vehicle (1) does not need to cause the rear side vehicle (2) to yield right of way, and then the process proceeds to the next step. In the next step, the speed generation unit (43) of the vehicle control unit (40) generates a lane keeping speed (step S236). A similar process to process step S202 is executed.

[0069] When process step S204, S210, S216, S222, S234, or S236 is executed, the vehicle ECU (10) consequently controls the steering and speed of the vehicle (1) (step S238). A process similar to that in Fig. Process step S120 shown in Figure 4 is executed.

[0070] Since the inter-vehicle distance reduction speed is generated depending on the remaining distance (X), the ability to complete a lane change with automated driving is improved.

Claims

[1] A vehicle control system (100) mounted on a host vehicle (1), the vehicle control system comprising: a vehicle detection unit (32) configured to detect a rear lateral vehicle in a rearward region of the host vehicle, the rear lateral vehicle being one of nearby vehicles traveling in a second lane adjacent to the first lane in which the host vehicle is traveling; a remaining distance detection unit (41) configured to detect a remaining distance from a current position of the host vehicle to a position at which the host vehicle completes a lane change; a lane change possibility determination unit (30) configured to determine whether the lane change is possible based on information acquired by the vehicle detection unit; and a vehicle control unit (40) configured to, when the lane change possibility determination unit determines that the lane change is not possible and the remaining distance is shorter than a first determination distance, control the steering of the host vehicle such that a position of the host vehicle in the vehicle width direction becomes a position closer to the second lane than a position when the remaining distance is longer than or equal to the first determination distance. [2] A vehicle control system according to claim 1, wherein: the vehicle detection unit is configured to detect a front lateral vehicle in a front region of the host vehicle, the front lateral vehicle being one of nearby vehicles traveling in a second lane; and the vehicle control unit is configured to control a speed of the host vehicle so as to reduce an inter-vehicle distance between the host vehicle and the front lateral vehicle when conditions i) to iii) are all met: i) the lane change possibility determination unit determines that the lane change is not possible, (ii) there is the front lateral vehicle and the rear lateral vehicle, and iii) the remaining distance is shorter than a predetermined second determination distance. [3] The vehicle control system according to claim 2, wherein the vehicle control unit is configured to control the speed of the host vehicle so that the inter-vehicle distance between the host vehicle and the front lateral vehicle increases when the conditions iv) to vi) are all satisfied: (iv) the lane change possibility determination unit determines that the lane change is not possible, v) there is the front lateral vehicle, and vi) there is no rear lateral vehicle. [4] A vehicle control system according to claim 2 or 3, wherein the vehicle control unit is arranged to control the speed of the host vehicle so that the inter-vehicle distance between the host vehicle and the rear lateral vehicle increases when the conditions vii) to ix) are all satisfied: vii) the lane change possibility determination unit determines that the lane change is not possible, viii) there is the rear lateral vehicle, and ix) there is no front lateral vehicle. [5] A vehicle control system according to any one of claims 1 to 4, wherein the lane change possibility determination unit is arranged to to calculate a time to collision with a nearby vehicle that is one of nearby vehicles traveling in the second lane, and to determine that the lane change is possible if the time until collision is longer than a predetermined determination time.

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