VEHICLE TRAVEL CONTROL DEVICE

Abstract

A vehicle travel control device (1, 1A) that causes a vehicle (V) to travel based on a target travel trajectory, comprising: an acquisition unit (13) configured to acquire a direction and a traveling position (3) of the vehicle (V); a trajectory generation unit (14) configured to generate a target travel trajectory from the travel position (3) to a lane center position of a target lane based on a direction of the vehicle (V), the travel position (3) and the lane center position of the target lane; a travel control unit (15) configured to cause the vehicle (V) to travel using the target travel trajectory; and a determination unit (14) configured to determine whether the direction of the vehicle (V) is outward in a lane width direction based on a lane center of the target lane, wherein, when it is determined by the determination unit (14) that the direction of the vehicle (V) is outward in the lane width direction based on the lane center of the target lane, the trajectory generation unit (14) generates the target travel trajectory on the assumption that the direction of the vehicle (V) is a direction along the lane center of the target lane or inward in the lane width direction based on the lane center of the target lane.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is based on Japanese patent application number 2015 - 094 282 (JP 2016 - 210 255 A), filed on May 1, 2015, the disclosure of which is incorporated by reference. TECHNICAL FIELD

[0002] The present invention relates to a vehicle travel control device. BACKGROUND

[0003] The description of US patent application US 2012 / 0 283 911 A1 discloses a device that controls the steering of a vehicle. This device generates a smooth target travel trajectory from a traveling position to a lane center position based on the direction (vehicle yaw angle) of the vehicle and the time required for the vehicle to reach a lane center from a traveling position, and adjusts the steering of the vehicle using the target travel trajectory. OVERVIEW

[0004] However, when the direction of the vehicle is outward relative to the extending direction of the lane center position, the device disclosed in the specification of US 2012 / 0 283 911 A1 generates a target travel trajectory that extends in the outward direction (direction away from the lane center) of the lane. When the vehicle is caused to travel using such a target travel trajectory, the vehicle moves in an arc in a direction away from the lane center position, and thus, there may be a fear that the vehicle will leave the lane.

[0005] Reference is also made to DE 10 2013 017 212 A1, DE 10 2005 056 211 A1, DE 10 2007 061 900 A1 and US 2009 / 0 319 113 A1, which were identified as prior art.

[0006] In this technical field, when the vehicle is caused to travel from the travel position to the lateral target position based on the target travel trajectory, a vehicle travel control device that can prevent the vehicle from leaving the travel lane is required.

[0007] According to one aspect of the present invention, there is provided a vehicle travel control device that causes a vehicle to travel based on a target travel trajectory, including: an acquisition unit configured to acquire a direction and a travel position of the vehicle; a travel trajectory generation unit configured to generate a target travel trajectory from the travel position to a lane center position of a target lane based on a direction of the vehicle, the travel position, and the lane center position of the target lane; a travel control unit configured to cause the vehicle to travel using the target travel trajectory;and a determination unit configured to determine whether the direction of the vehicle is outward in a lane width direction based on a lane center of the target lane, wherein, when the determination unit determines that the direction of the vehicle is outward in the lane width direction based on the lane center of the target lane, the trajectory generation unit generates the target travel trajectory on the assumption that the direction of the vehicle is a direction along the lane center of the target lane or inward in the lane width direction based on the lane center of the target lane.

[0008] When the direction of the vehicle is outward in the lane width direction based on the lane center of the target lane, the vehicle travel control device generates a target travel trajectory assuming that the direction of the vehicle is a direction along the lane center of the target lane or inward in the lane width direction based on the lane center of the target lane. Thus, it is possible to prevent the target travel trajectory from arcing outward in the lane (a direction away from the lane center). Thus, when the travel control device causes the vehicle to travel based on the target travel trajectory, it is possible to prevent the vehicle from leaving the lane.

[0009] In one embodiment, the trajectory generation unit may generate the target travel trajectory using a lane along which the vehicle is traveling as the target lane. In this case, if the travel control device causes the vehicle to be located at the center of the vehicle's travel lane, it is possible to prevent the vehicle from leaving the lane.

[0010] In one embodiment, the trajectory generation unit may generate the target travel trajectory using a lane adjacent to a lane along which the vehicle is traveling as the target lane. In this case, when the travel control device changes a lane, for example, from the current lane to an adjacent lane, it is possible to prevent the vehicle from leaving the lane to the opposite side of the adjacent lane of the lane change target.

[0011] According to various aspects and embodiments of the present invention, when a vehicle is caused to travel from the travel position to the lateral target position based on the target travel trajectory, the vehicle is to be prevented from leaving the travel lane. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram illustrating a configuration of a vehicle including a vehicle travel control device according to a first embodiment. Fig. Figure 2 is a diagram illustrating an example of lateral target positions. Fig. 3A to Fig. 3E are diagrams illustrating an example of target travel trajectories. Fig. 4A to Fig. 4C are diagrams illustrating an example in which target travel trajectories are generated assuming the direction of the vehicle. Fig. 5 is a flowchart illustrating an example of vehicle control processing of the vehicle travel control apparatus according to the first embodiment. Fig. 6 is a block diagram illustrating a configuration of the vehicle including a vehicle travel control device according to a second embodiment. Fig. 7A to Fig. 7C are diagrams illustrating an example of target travel trajectories during a lane change. Fig. 8A to Fig. 8C are diagrams illustrating an example in which target travel trajectories are generated assuming the direction of the vehicle. Fig. 9 is a flowchart illustrating an example of vehicle control processing of the vehicle travel control apparatus according to the second embodiment. DETAILED DESCRIPTION

[0012] Embodiments of the present invention will be explained below with reference to the drawings. However, in the following description, identical or equivalent components are denoted by the same reference numerals, and thus their description will not be repeated. [First embodiment]

[0013] Fig. 1 is a block diagram illustrating a configuration of a vehicle V including a vehicle travel control device 1 according to a first embodiment. As shown in Fig. As shown in Figure 1, a vehicle system 100 is mounted in the vehicle V, such as a passenger car. The vehicle system 100 includes the vehicle travel control device 1. The vehicle travel control device 1 is a device that causes the vehicle V to travel based on a target travel trajectory. The target travel trajectory refers, for example, to a line connecting travel positions that are targets for the vehicle V in a lane within a predetermined range. The term "causing the vehicle V to travel" means traveling based on automatic driving or traveling based on driving assistance.As will be described later, the vehicle travel control device 1 is, for example, a device that causes the vehicle V to travel along a target travel trajectory based on automatic travel, or a device that causes the vehicle V to travel along a target travel trajectory by system intervention in the driving operation of a driver.

[0014] The vehicle system 100 includes an external sensor 2, a GPS (Global Positioning System) receiving unit 3, an internal sensor 4, a map database 5, a navigation system 6, a human-machine interface (HMI) 7, an actuator 8, and an electronic control unit (ECU) 10. The external sensor 2, the GPS receiving unit 3, the internal sensor 4, the map database 5, the navigation system 6, the HMI 7, the actuator 8, and the ECU 9 are connected to a network that performs communication using, for example, a CAN (Controller Area Network) communication circuit and can perform two-way communication.

[0015] The external sensor 2 is a detection device that detects an external situation, which is environmental information of the vehicle V. The external sensor 2 includes at least a camera, a radar, and a so-called LIDAR (Laser Imaging Detection and Ranging).

[0016] The camera is an imaging device that images the external situation of the vehicle V. The camera is provided, for example, on the rear of the windshield of the vehicle V. The camera can be a monocular camera or a stereo camera. The stereo camera includes, for example, two imaging units arranged to reproduce binocular parallax. Imaging information from the stereo camera also includes depth direction information. The camera outputs the imaging information about the external situation of the vehicle V to the ECU 10.

[0017] The radar detects an object outside the vehicle V using radio waves. The radio waves are, for example, millimeter waves. The radar transmits radio waves to the surroundings of the vehicle V and receives radio waves reflected from an object to thereby detect the object. The radar can output, for example, a distance or a direction to the object as object information. The radar outputs the information about the detected object to the ECU 10. Meanwhile, when sensor fusion is performed at a subsequent stage, reception information of the reflected radio waves can be output to the ECU 10.

[0018] The LIDAR detects an object outside the vehicle V using light. The LIDAR transmits light to the surroundings of the vehicle V and receives light reflected from an object to thereby measure a distance to a reflection point and detect the object. The LIDAR can output, for example, a distance or a direction to the object as object information. The LIDAR outputs the information about the detected object to the ECU 10. Meanwhile, if sensor fusion is performed at a subsequent stage, reception information of the reflected light can be output to the ECU 10. However, the camera, the LIDAR, and the radar do not necessarily have to be provided redundantly.

[0019] The GPS receiving unit 3 receives a signal from three or more GPS satellites and acquires location information indicating the position of the vehicle V. The location information includes, for example, latitude and longitude. The GPS receiving unit 3 outputs the measured position information of the vehicle V to the ECU 10. However, other means available in the vehicle V that can specify the latitude and longitude may be used instead of the GPS receiving unit 3.

[0020] The internal sensor 4 is a detector that detects information according to the traveling state of the vehicle V. The internal sensor 4 includes a sensor that detects the direction of the vehicle. Such a sensor includes, for example, a yaw rate sensor. Alternatively, a sensor that detects a tire angle can be used as the sensor that detects the direction of the vehicle. Such a sensor includes, for example, a steering sensor. Meanwhile, the internal sensor 4 may further include a speed sensor and an acceleration sensor.

[0021] The yaw rate sensor is a detector that detects a yaw rate (rotational angular velocity) around the vertical axis of the center of gravity of the vehicle V. For example, a gyro sensor can be used as the yaw rate sensor. The yaw rate sensor outputs yaw rate information, including the yaw rate of the vehicle V, to the ECU 10.

[0022] The steering sensor is, for example, a detector that detects the rotational state of the steering. The detection value of the rotational state is, for example, a steering torque or rudder position. The steering sensor is provided, for example, on the steering shaft of the vehicle V. The steering sensor outputs information including the steering torque or the rudder position of the steering to the ECU 10.

[0023] The speed sensor is a detector that detects the speed of the vehicle V. For example, a wheel speed sensor that is provided on the wheel of the vehicle V or a drive shaft and the like that rotates integrally with the wheel and detects the rotational speed of the wheel can be used as the speed sensor. The speed sensor outputs speed information (wheel speed information) including the speed of the vehicle V to the ECU 10.

[0024] The acceleration sensor is a detector that detects the acceleration of the vehicle V. The acceleration sensor includes, for example, a forward-backward acceleration sensor that detects the acceleration of the vehicle V in a forward-backward direction and a lateral acceleration sensor that detects the lateral acceleration of the vehicle V. The acceleration sensor outputs acceleration information including the acceleration of the vehicle V to the ECU 10.

[0025] The map database 5 is a database including map information. The map database 5 is formed, for example, within a hard disk drive (HDD) mounted in the vehicle V. The map information includes, for example, position information of a road, information of a road shape, and position information of an intersection point and a junction point. The information of a road shape includes, for example, a curve, the type of a straight line section, the curvature of the curve, and the like. Further, when the vehicle system 100 uses position information of a shielding structure such as a building or a wall, or a SLAM (Simultaneous Localization and Mapping) method, the output signal of the external sensor 2 may be included in the map information.Meanwhile, the map database may be stored in a computer of a facility such as an information processing center that can communicate with the vehicle V.

[0026] The navigation system 6 is a device that guides the driver of the vehicle V to a destination specified on a map by the driver of the vehicle V. The navigation system 6 calculates a travel route of the vehicle V based on the position information of the vehicle V measured by the GPS receiving unit 3 and the map information of the map database 5. The route may be, for example, a route in which the travel lane of the vehicle V is specified at the intervals of multiple lanes. The navigation system 6 calculates, for example, a destination route from the position of the vehicle V to a destination and notifies a driver of the destination route by displaying a display and sound output from a speaker. The navigation system 6 outputs, for example, information of the destination route of the vehicle V to the ECU 10.Furthermore, the navigation system 6 may be configured to include a gyro sensor and output information for calculating the direction of the vehicle V to the ECU 10. Meanwhile, the navigation system 6 may use information stored in a computer of a facility, such as an information processing center, that can communicate with the vehicle V. For example, the navigation system 6 may obtain traffic jam information indicating congestion of a road through communication from the computer of a facility. Furthermore, a processing section executed by the navigation system 6 may be executed by the computer of a facility.

[0027] The HMI 7 is an interface for outputting and inputting information between an occupant (including a driver) of the vehicle V and the vehicle system 100. The HMI 7 includes, for example, a display panel for displaying image information for an occupant, a speaker for outputting sound, an operation button or a touch panel for an occupant to perform an input operation, and the like. The HMI 7 includes an ON / OFF switch, which is an input unit that inputs an occupant's request operation for automatic driving, a start of automatic driving, or a start of driving assistance. The ON / OFF switch can be configured to input a request operation according to an end of automatic driving and an end of driving assistance.When a request operation according to the start or end of automatic driving or driving assistance is performed by an occupant, the ON / OFF switch outputs information indicating the start or end of automatic driving or driving assistance to the ECU 10. However, the input unit is not limited to a switch and may be any unit that can be used insofar as the unit can input information that can determine an occupant's intention to start or end automatic driving or driving assistance. For example, the input unit may be a start button, an off button, or the like, and may be an object of a switch or knob displayed on a screen that can be operated by an occupant.The HMI 7 can output information to an occupant using a portable information terminal that is wirelessly connected, and can receive an input operation from an occupant using a portable information terminal.

[0028] The actuator 8 is a device that performs travel control of the vehicle V. The actuator 8 includes at least a motor actuator, a brake actuator, and a steering actuator. The motor actuator controls the amount of air (throttle valve opening) supplied to an engine according to a control signal from the ECU 10, and controls the driving force of the vehicle V. Meanwhile, when the vehicle V is a hybrid car or an electric car, the motor actuator controls the driving force of an electric motor as a driving power source.

[0029] The brake actuator controls a braking system according to a control signal from the ECU 10 and controls a braking force applied to the wheel of the vehicle V. For example, a hydraulic braking system can be used as the braking system. The steering actuator controls the drive of an assist motor that controls a steering torque in an electric power steering system according to the control signal from the ECU 10. The steering actuator controls the steering torque of the vehicle V.

[0030] The ECU 10 controls the vehicle V. The ECU 10 is an electronic control unit including a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), a CAN communication circuit, and the like. The ECU 10 is connected to a network that performs communication using, for example, the CAN communication circuit, and is communicatively connected to the aforementioned components of the vehicle V. The ECU 10 inputs and outputs data by operating the CAN communication circuit, for example, based on a signal output by the CPU, stores the input data in the RAM, loads a program stored in the ROM into the RAM, and executes the program stored in the RAM, thereby realizing functions of the components of the ECU 10, which will be described later.Meanwhile, the ECU can consist of several electronic control units.

[0031] The ECU 10 includes an external situation recognition unit 11, a vehicle position recognition unit 12, a travel state recognition unit 13 (an example of an acquisition unit), a travel plan generation unit 14 (an example of a determination unit and a trajectory generation unit), and a travel control unit 15 (an example of a travel control unit). The vehicle travel control device 1 is configured to include the travel state recognition unit 13, the travel plan generation unit 14, and the travel control unit 15. The vehicle travel control device 1 may include the travel state recognition unit 13, the travel plan generation unit 14, and the travel control unit 15, and may not necessarily include the external situation recognition unit 11 and the vehicle position recognition unit 12.

[0032] The external situation detection unit 11 detects the external situation of the vehicle V based on environmental information of the vehicle V. The external situation detection unit 11 is realized, for example, by operating the CAN communication circuit based on a signal output by the CPU, loading a program stored in the ROM into the RAM, and executing the program loaded into the RAM.

[0033] The environmental information is information indicating an environment or a situation within a predetermined range of the vehicle V. For example, the external situation recognition unit 11 acquires a detection result of the external sensor 2 as the environmental information of the vehicle V. The detection result of the external sensor 2 includes, for example, imaging information of a camera, object information of a radar, object information of a LIDAR, or the like. Alternatively, the external situation recognition unit 11 may acquire information of the navigation system 6 as the environmental information of the vehicle V through communication.

[0034] The external situation of the vehicle V refers to an environment or a situation within a predetermined range of the vehicle V. For example, the external situation of the vehicle V includes a branch of a road, a connection point, traffic regulations, the position of the lane boundary line of the driving lane with respect to the vehicle V, or the position and road width of the lane center, the shape of a road, and the like. The shape of a road is, for example, the curvature of a driving lane, the gradient change of a road surface effective in the visibility of the estimation of the external sensor 2, undulation, or the like. Further, the external situation of the vehicle V may be the situation of objects such as an obstacle in the surroundings of the vehicle V or other vehicles.The situation of an object may be, for example, information for distinguishing between a fixed obstacle and a moving obstacle, the position of an obstacle with respect to the vehicle V, the direction of movement of an obstacle with respect to the vehicle V, the relative speed of an obstacle with respect to the vehicle V, and the like.

[0035] The vehicle position detection unit 12 detects the vehicle position (position of the vehicle V on a map) of the vehicle V. The vehicle position detection unit 12 is implemented, for example, by operating the CAN communication circuit based on a signal output by the CPU, loading a program stored in the ROM into the RAM, and executing the program loaded into the RAM. The vehicle position detection unit 12 detects, for example, the position of the vehicle V on a map based on the position information of the vehicle V received in the GPS receiving unit 3 and the map information of the map database 5. Meanwhile, the vehicle position detection unit 12 can acquire and detect a vehicle position used in the navigation system 6 from the navigation system 6.If the vehicle position can be measured by a sensor installed outside, for example, on a road, the vehicle position detecting unit 12 can obtain the vehicle position from this sensor through communication.

[0036] The traveling state detection unit 13 detects the traveling state of the vehicle V based on the detection result of the internal sensor 4. The traveling state detection unit 13 is implemented, for example, by operating the CAN communication circuit based on a signal output by the CPU, loading a program stored in the ROM into the RAM, and executing the program loaded into the RAM. The detection result of the internal sensor 4 includes, for example, yaw rate information from the yaw rate sensor. Alternatively, the detection result of the internal sensor 4 may include the rudder angle of the steering sensor. Further, the detection result of the internal sensor 4 may include speed information from the speed sensor, acceleration information from the acceleration sensor, or the like.

[0037] The direction of the vehicle V and the traveling position of the vehicle V are included in the information indicating the traveling state of the vehicle V. The traveling state detection unit 13 detects the direction of the vehicle V and the traveling position of the vehicle V based on the detection results of the external situation detection unit 11 and the vehicle position detection unit 12 and the detection result of the internal sensor 4. The direction of the vehicle V refers, for example, to the direction of the vehicle V with respect to the traveling lane of the vehicle V, and as a more specific example, to a direction in which the vehicle V is directed with respect to the extending direction (direction in which the vehicle V is traveling) of the traveling lane of the vehicle V. For example, the direction of the vehicle V can be represented by a yaw angle in which the extending direction of the lane center of the traveling lane is set to 0.For example, the yaw angle can be calculated from the yaw rate information. Alternatively, the direction of the vehicle V can be estimated from the rudder position of the steering sensor. Alternatively, the direction of the vehicle V can be obtained from the navigation system 6. Alternatively, the direction of the vehicle V can be obtained only based on the detection result of the lane boundary line obtained from the external sensor 2 (camera) or the like. Further, the traveling position of the vehicle V refers to a vehicle position when the vehicle is traveling and is a position serving as the starting point of a target traveling trajectory.

[0038] The travel plan generation unit 14 generates a target travel trajectory. The travel plan generation unit 14 is implemented, for example, by operating the CAN communication circuit based on a signal output by the CPU, loading a program stored in the ROM into the RAM, and executing the program loaded into the RAM. The target travel trajectory is used, for example, in automatic driving or driving assistance to perform control such that the vehicle V does not deviate from the lane.

[0039] Automatic driving refers, for example, to controlling the vehicle V using a target travel trajectory. That is, automatic driving refers, for example, to realizing the travel of the vehicle V only by controlling the vehicle system 100 in a state where driver intervention is not performed, without performing a driver steering operation. Driving assistance refers, for example, to causing the vehicle V to drive in coordination with the steering operation based on the target travel trajectory and the amount of the steering operation. That is, driving assistance refers to a state where both the driver and the vehicle system 100 can affect the travel of the vehicle V, and realizing the travel of the vehicle V based on at least the amount of the driver steering operation in a state where system intervention can be performed.

[0040] The travel plan generation unit 14 generates a target travel trajectory in advance of vehicle control. The term "before vehicle control" means before the control is executed, and this can be during automatic driving or during driving assistance. For example, when information indicating the start of automatic driving or driving assistance is acquired from an ON / OFF switch, the travel plan generation unit 14 can generate a target travel trajectory.

[0041] The travel plan generation unit 14 generates a target travel movement plan from a travel position to a lateral target position, for example, based on the direction and travel position of the vehicle V detected by the travel state detection unit 13, and the lateral target position. The lateral target position refers to the position of a lane width in a lateral direction set in a target lane, and serves, for example, as a vehicle control target. The target lane refers to a target lane along which the vehicle V is caused to travel. When automatic driving or driving assistance is performed so that the vehicle V does not leave the lane, the lane serves as a travel lane (lane along which the vehicle travels). The lateral target position can be set during automatic driving or driving assistance and can be set in advance.An example of the lateral target position includes a lane center position, a position offset from the lane center position by a predetermined distance, or the like.

[0042] Fig. Figure 2 is a diagram illustrating an example of the lateral target position. In the Fig. The example shown in Figure 2 shows a scene in which the vehicle V is traveling along a lane 50 partitioned by lane boundary lines L1 and L2. As shown in Fig. 2, the vehicle V travels along the traveling lane 50 at a traveling position P3 in a direction Y. Here, the lateral target position P4 is set to a lane center position. The lateral target position P4 is calculated (detected) based on, for example, the positions of the lane boundary lines L1 and L2. As a more specific example, the lateral target position P4 is a lane center position and is calculated as an intermediate position between predetermined positions P1 and P2 of the lane boundary lines L1 and L2. A plurality of lateral target positions P4 may be calculated at predetermined intervals ahead of the vehicle V along the traveling lane 50. In the drawing, continuous lateral target positions P4 are shown. A direction Z that passes continuous lateral target positions P4 is a direction along the lane center.In other words, the direction Z passing the continuous lateral target positions P4 is set to the extending direction of the lane 50 (extending direction of the lane center position of the target lane).

[0043] The travel plan generation unit 14 generates, for example, a target travel trajectory using a geometric method based on the direction Y of the vehicle V, the travel position P3, and the lateral target position P4. Fig. 3A to 3E are diagrams illustrating an example of target travel trajectories. As in Fig. As shown in Fig. 3A, the travel plan generation unit 14 generates a target travel trajectory R1 that smoothly connects the travel position P3 and the lane center position (lateral target position P4) using a geometric method under constraint conditions in which a start point is set to the travel position P3, an end point is set to the lane center position (lateral target position P4) in front of the vehicle V, and the extending direction of a trajectory at the travel position P3 is set to a direction Y1. The travel plan generation unit 14 generates a target travel trajectory using, for example, a composite clothoid. Alternatively, the travel plan generation unit 14 may generate a target travel trajectory using not only the travel position P3 and the lane center position (lateral target position P4) but also a target speed and a target time.In this case, the travel plan generation unit 14 generates a target travel trajectory that can reach the lane center position (lateral target position P4) within the target time at the target speed. Alternatively, the travel plan generation unit 14 may generate a target travel trajectory such that the vehicle V travels in a condition that satisfies a criterion such as safety, regulatory compliance, or driving efficiency. Furthermore, the travel plan generation unit 14 may generate a target travel trajectory of the vehicle to prevent contact with an object based on the situation of an object in the surroundings or the vehicle V.

[0044] Here, the direction of the vehicle V may be set to be outward in a lane width direction or to be inward in the lane width direction based on the lateral target position P4 in the lane 50. Specifically, when the lateral target position P4 is a lane center position, the direction of the vehicle V may be set to be outward in the lane width direction or to be inward in the lane width direction based on the lane center of the lane 50. Next, a case where the lateral target position is a lane center position will be described by way of example.

[0045] First, outward in the lane width direction is described. The expression "outward in the lane width direction based on the lane center" means that the vehicle V is directed toward the lane boundary line rather than the lane center. That is, this lane boundary line is a left lane boundary line of the traveling lane when the traveling position is further left than the lane center position (lateral target position), and is a right lane boundary line of the traveling lane when the traveling position is further right than the lane center position (lateral target position). For example, in the Fig. 3B, the direction of the vehicle V is set to be outward (direction Y2) in the lane width direction based on the lane center (continuous lateral target positions P4) of the lane 50, and is directed toward the lane boundary line L1. Similarly, in the example shown in Fig. 3C, the direction of the vehicle V is set to be outward in the lane width direction (direction Y3) based on the lane center (continuous lateral target positions P4) of the traveling lane 50, and is directed toward the lane boundary line L2. Meanwhile, in a case where the vehicle V is directed toward the lane boundary line rather than the lane center, even if the vehicle V is located at the lane center, the direction of the vehicle V is set to be outward in the lane width direction based on the lane center.In a case where the target travel trajectory R2 (target travel trajectory R3) that evenly connects the travel position P3 and the lane center position (target lateral position P4) in front of the vehicle V is generated using the above-mentioned method, when the vehicle V is outward in the lane width direction based on the lane center, the target travel trajectory R2 (target travel trajectory R3) is set to a trajectory that expands in the outward direction of the travel lane 50, and thus there may be a concern about the target travel trajectory R2 (target travel trajectory R3) and the lane boundary line L1 (lane boundary line L2) crossing each other.

[0046] Next, inward in the lane width direction is described. The expression "inward in the lane width direction based on the lane center" means that the vehicle V is directed toward the lane center. For example, in the Fig. 3D and Fig. In the examples illustrated in FIG. 3E, the direction of the vehicle V is set to be inward (directions Y4 and Y5) in the lane width direction based on the lane center (continuous lateral target positions P4) of the traveling lane 50, and is directed toward the lane center. In a case where a target travel trajectory R4 (target travel trajectory R5) that smoothly connects the traveling position P3 and the lane center position (lateral target position P4) in front of the vehicle V is generated using the above method, when the vehicle V is inward in the lane width direction based on the lane center, the target travel trajectory R4 (target travel trajectory R5) and the lane boundary lines L1 and L2 do not intersect. Meanwhile, even if the direction of the vehicle V is a direction along the lane center (the same direction as the extending direction of the lateral target position P4), the target travel trajectory does not intersect the lane boundary lines L1 and L2.

[0047] As described above, in a case where the target travel trajectories R2 and R3 are assumed, if the direction of the vehicle V is set to be outward in the lane width direction based on the lane center (continuous lateral target positions P4), there may be a concern that the vehicle V will leave the travel lane 50. For this reason, the travel plan generation unit 14 determines whether the direction of the vehicle V is outward in the lane width direction based on the lane center (continuous lateral target positions P4) of the travel lane 50 as processing for generating a target travel trajectory, based on the detection result of the travel state detection unit 13.If it is determined that the direction of the vehicle V is outward in the lane width direction based on the lane center (continuous lateral target positions P4) of the travel lane 50, the travel plan generation unit 14 assumes that the direction of the vehicle V is a direction along the lane center of the travel lane 50. Alternatively, the travel plan generation unit 14 assumes that the direction of the vehicle V is inward in the lane width direction based on the lane center (continuous lateral target positions P4) of the target lane. Meanwhile, the term "assume" as used herein refers to changing the direction of the vehicle V used in the calculation. The travel plan generation unit 14 generates a target travel trajectory using the assumed direction of the vehicle V.

[0048] Fig. 4A to Fig. 4C are diagrams illustrating an example in which target travel trajectories are generated assuming the direction of the vehicle. Fig. 4A is the same as the one in Fig. 3B, the direction of the vehicle V is set to be outward (direction Y2) in the lane width direction based on the lane center (continuous lateral target positions P4) in the travel lane 50, and is directed toward the lane boundary line L1. For this reason, when it is determined that the direction of the vehicle V is outward in the lane width direction based on the lane center (continuous lateral target positions P4), the travel plan generation unit 14 assumes that the direction of the vehicle V is a direction along the lane center (continuous lateral target positions P4), as shown in Fig. 4B. That is, the travel plan generation unit 14 replaces the direction Y2 of the vehicle V with a direction Y20. Alternatively, as shown in Fig. 4C, the travel plan generation unit 14 assumes that the direction of the vehicle V is inward in the lane width direction based on the lane center (continuous lateral target positions P4). That is, the travel plan generation unit 14 replaces the direction Y2 of the vehicle V with a direction Y21. The travel plan generation unit 14 generates a target travel trajectory using the assumed direction of the vehicle V. Thereby, any one of target travel trajectories R20 and R21 where there is no possibility of lane departure is generated instead of the target travel trajectory R2 where there is a possibility of lane departure.

[0049] The travel control unit 15 causes the vehicle V to travel using a target travel trajectory. The travel control unit 15 is implemented, for example, by operating the CAN communication circuit based on a signal output by the CPU, loading a program stored in the ROM into the RAM, and executing the program loaded into the RAM. In the case of automatic travel, the travel control unit outputs a control signal to the actuator 8 based on the target travel trajectory generated by the travel plan generation unit 14 and controls the travel of the vehicle V. On the other hand, in the case of driving assistance, the travel control unit 15 performs system intervention based on the target travel trajectory generated by the travel plan generation unit 14 while reflecting a driver steering input in the travel of the vehicle V.

[0050] Next, processings executed by the vehicle travel control device 1 will be described. Fig. 5 is a flowchart illustrating an example of vehicle travel processing of the vehicle travel control device 1 according to the present embodiment. Fig. For example, the control processing shown in Fig. 5 is executed when information indicating the start of automatic driving or driving assistance is input by an ON / OFF switch.

[0051] As in Fig. As shown in Figure 5, the vehicle travel control device 1 acquires the surrounding information of the vehicle V as information acquisition processing (S10). First, the vehicle position detection unit 12 detects a vehicle position based on the position information of the vehicle V received in the GPS reception unit 3 and the map information of the map database. The external situation detection unit 11 detects the external situation of the vehicle V based on the detection result of the external sensor 2 or information provided by the navigation system 6. The travel condition detection unit 13 detects the travel condition of the vehicle V based on the detection result of the external situation detection unit 11 and the detection result of the internal sensor 4.That is, in the information acquisition processing, at least the direction of the vehicle V, the traveling position, the lane boundary line of the driving lane and the lateral target position are acquired.

[0052] Next, the travel plan generation unit 14 determines whether the direction of the vehicle V obtained in the information acquisition processing is outward in the lane width direction as a determination processing (S12) in a vehicle direction based on the lane center (continuous lateral target positions P4). For example, as shown in Fig. 3B and Fig. As shown in Figure 3C, when the direction of the vehicle V is directed toward the lane boundary line based on the lane center (continuous lateral target positions P4), the travel plan generation unit 14 determines that the direction of the vehicle V is outward in the lane width direction. If the direction of the vehicle V is outward, the processing proceeds to vehicle direction assumption processing.

[0053] The travel plan generation unit 14 assumes that the direction of the vehicle V is a direction along the lane center (extension direction Z of continuous lateral target positions P4) as a vehicle direction assumption processing (S14) ( Fig. 4B). Alternatively, the travel plan generation unit 14 assumes that the direction of the vehicle V in the lane width direction is inward based on the lane center (continuous lateral target positions P4) ( Fig. 4C). Once the acceptance processing is completed, processing proceeds to target travel trajectory generation processing.

[0054] The travel plan generation unit 14 generates a target travel trajectory that evenly connects the travel position and the lateral target position using a geometric method under constraint conditions in which a start point is set as the travel position, an end point is set as the lateral target position in front of the vehicle V, and the extending direction of a trajectory at the travel position is set to the vehicle direction of the travel position, as the target travel trajectory generation processing (S16). Here, the travel plan generation unit generates a target travel trajectory using the direction of the vehicle assumed in the assumption processing of S14. At this time, any of the target travel trajectories R20 and R21 defined in Fig. 4B and Fig. 4C. When the target travel trajectory generation processing is completed, the processing proceeds to the vehicle control processing.

[0055] The travel control unit 15 causes the vehicle V to travel using the target travel trajectory as the vehicle control processing (S18). When the vehicle control processing is completed, the Fig. The tax processing shown in Figure 5 is completed.

[0056] On the other hand, if the direction of the vehicle V is not outward based on the lane center (continuous lateral target position P4) in the determination processing of S12, the processing proceeds to the target travel trajectory generation processing. The travel plan generation unit 14 generates a target travel trajectory using the direction of the vehicle V obtained in the information acquisition processing (S16), and the travel control unit 15 causes the vehicle V to travel using the target travel trajectory (S18). When the vehicle control processing is completed, the Fig. The tax processing shown in Figure 5 is completed.

[0057] As described above, the Fig. 5 is completed. By executing the flowchart shown in Fig. As shown in Fig. 5, when the direction of the vehicle V in the vehicle width direction is outward based on the lane center (continuous lateral target positions P4), the vehicle control device 1 assumes that the direction of the vehicle V is a direction along the lane center (extending direction Z of the continuous lateral target positions P4), or assumes that the direction of the vehicle V in the lane width direction is inward based on the lane center (continuous lateral target positions P4). Therefore, when the vehicle V is caused to travel from the travel position P3 to the lane center position (lateral target position P4) based on the target travel trajectory, it is possible to prevent the vehicle V from leaving the travel lane 50.

[0058] As described above, according to the vehicle travel control device 1 of the first embodiment, when the vehicle V is caused to be located at the target lateral position P4 of the traveling lane 50 of the vehicle V, it is possible to prevent the vehicle V from leaving the traveling lane 50.

[0059] Furthermore, according to the vehicle travel control device 1 of the first embodiment, when the direction Y of the vehicle V is outward in the lane width direction based on the lane center (continuous lateral target positions P4), a target travel trajectory is generated assuming that the direction of the vehicle V is a direction along the lane center (extension direction Z of the continuous lateral target positions P4), or assuming that the direction Y of the vehicle V is inward in the lane width direction based on the lane center (continuous lateral target positions P4), and thus, it is possible to prevent the target travel trajectory from drawing an arc that widens in the outward direction of the traveling lane 50 (direction away from the lane center). Thus, when this travel control device causes the vehicle travel based on the target travel trajectory, it is possible to prevent the vehicle from leaving the traveling lane. [Second embodiment]

[0060] Next, a vehicle travel control device 1A according to a second embodiment will be described. In this embodiment, the same configurations and processing as those of the first embodiment will not be described, and differences from the first embodiment will be described.

[0061] The vehicle travel control device 1A according to the present embodiment is a device that changes the lane of the vehicle V from the traveling lane to an adjacent lane based on a target travel trajectory. Fig. 6 is a block diagram illustrating a configuration of the vehicle V including the vehicle travel control device 1A according to the second embodiment. As shown in Fig. 6, a vehicle system 100A is the same as the vehicle system 100 of the first embodiment except that a direction indicator 9, an external situation recognition unit 11A, and a travel plan generation unit 14 are included therein.

[0062] The direction indicator 9 is a device that inputs a driver's operation of the vehicle V and consists, for example, of a turn signal lever and an operation detection unit. The operation detection unit is provided, for example, for the turn signal lever and detects an operation of the turn signal lever performed by a driver of the vehicle V. The operation detection unit detects whether a driver's operation of the turn signal lever is a right turn signal operation or a left turn signal operation as operation information. The direction indicator 9 outputs the detected operation information to the ECU 10.

[0063] Compared with the external situation detection unit 11A, the external situation detection unit 11A has an increase in the type of information detected as the external situation of the vehicle V. Specifically, the external situation of the vehicle V also includes the road width of an adjacent lane, a center position, the shape of a road, and the like. Furthermore, the external situation of the vehicle V may include information of other vehicles traveling along an adjacent lane.

[0064] The travel plan generation unit 14A differs from the travel plan generation unit 14 in the target lane. The travel plan generation unit 14A sets a lane adjacent to the lane along which the vehicle V is traveling as the target lane based on operation information of the direction indicator 9. The travel plan generation unit 14A sets a lateral target position in the adjacent lane.

[0065] The travel plan generation unit 14A generates a target travel trajectory using a geometric method, for example, based on the direction Y of the vehicle V, the travel position P3, and a lateral target position P5. Fig. 7A to Fig. 7C are diagrams illustrating an example of the target travel trajectories during a lane change. In the Fig. 7A to Fig. The examples shown in Figure 7C depict scenes in which the vehicle V travels along the lane 50 partitioned by the lane braking lines L1 and L2 and changes lanes to an adjacent lane 51 partitioned by lane boundary lines L2 and L3. As shown in Fig. As shown in FIG. 7A, the travel plan generation unit 14A generates a target travel trajectory R6 that smoothly connects the travel position P3 and the lane center position (lateral target position P5) using a geometric method under constraint conditions in which a start point is set to the travel position P3, an end point is set to the lane center position (lateral target position P5) of the adjacent lane 51, and the extending direction of the trajectory at the travel position P3 is set to a direction Y6. The travel plan generation unit 14A generates a target travel trajectory using a composite clothoid as an example. Alternatively, the travel plan generation unit 14A may generate a target travel trajectory using not only the travel position P3 and the lane center position (lateral target position P5), but also a target speed and a target time.In this case, the travel plan generation unit 14A generates a target travel trajectory that can reach the lane center position (lateral target position) within the target time at the target speed. Alternatively, the travel plan generation unit 14 may generate a target travel trajectory such that the vehicle V travels in a condition that satisfies a criterion such as safety, legal regulations, or driving efficiency. Furthermore, the travel plan generation unit 14A may generate a target travel trajectory of a vehicle V to avoid contact with an object based on the situation of an object in the vicinity of the vehicle V.

[0066] Here, the direction of the vehicle V can be set outward or inward in the lane width direction based on the lane center (continuous lateral target positions P5) of the adjacent lane 51. First, the term "outward in the lane width direction" will be described. The term "outward in the lane width direction based on the lane center" as used herein is the same as that in the first embodiment and means that the vehicle V is directed toward the lane boundary line rather than the lane center (continuous lateral target positions P5). That is, the lane boundary line is a lane boundary line located on the opposite side to a lane or a lane change target, respectively. For example, in Fig. In the example shown in FIG. 7B, the direction of the vehicle V is set to be outward (direction Y7) in the lane width direction based on the lane center (continuous lateral target positions P5) of the adjacent lane 51, and is directed toward the lane boundary line L1. In a case where the target travel trajectory R7 that smoothly connects the travel position P3 and the lane center position (lateral target position P5) of the adjacent lane 51 is generated using the above method, when the vehicle is outward in the lane width direction based on the lane center (continuous lateral target positions P5) of the adjacent lane 51, the target travel trajectory R7 is set to a trajectory that expands in the outward direction of the travel lane 50, and thus, there may be a concern that the target travel trajectory R7 and the lane boundary line L1 intersect.

[0067] Next, the term "inward in the lane width direction" will be described. The term "inward in the lane width direction based on the lane center" as used here is the same as that in the first embodiment and means that the vehicle V is directed toward the lane center (continuous lateral target positions P5). For example, in the Fig. In the example shown in FIG. 7C, a direction Y8 of the vehicle V is set to be inward (direction Y8) in the lane width direction based on the lane center (continuous lateral target positions P5) of the adjacent lane 51, and is directed toward the lane center. In a case where a target travel trajectory R8 that smoothly connects the travel position P3 and the lane center position (lateral target position P5) of the adjacent lane 51 is generated using the above-mentioned method, when the vehicle is inward in the lane width direction based on the lane center (continuous lateral target positions P5) of the adjacent lane 51, the target travel trajectory R8 and the lane boundary line L1 do not intersect.Meanwhile, even if the direction of the vehicle V is a direction along the lane center of the adjacent lane 51 (the same direction as the extending direction of the lateral target position P5), the target travel trajectory does not cross the lane boundary line L1.

[0068] As described above, in a case where the target travel trajectory R7 is used, when the direction of the vehicle V in the lane width direction is outward based on the lane center (continuous lateral target positions P5) of the adjacent lane 51, there may be a concern about the vehicle V leaving the traveling lane 50. For this reason, the travel plan generation unit 14A determines whether the direction of the vehicle V in the lane width direction is outward based on the lane center (continuous lateral target positions P5) of the adjacent lane 51 as processing for generating a target travel trajectory based on the detection result of the traveling state detection unit 13.If it is determined that the direction of the vehicle V is outward in the lane width direction based on the lane center (continuous lateral target positions P5) of the adjacent lane 51, the travel plan generation unit 14A assumes that the direction of the vehicle V is a direction along the lane center of the adjacent lane 51 (extension direction Z of the continuous lateral target positions P5). Alternatively, the travel plan generation unit 14A assumes that the direction of the vehicle V is inward in the lane width direction based on the lane center (continuous lateral target positions P5) of the adjacent lane 51. However, the term "assume" as used herein refers to changing the direction of the vehicle V used in the calculation. The travel plan generation unit 14A generates a target travel trajectory using the assumed direction of the vehicle V.

[0069] Fig. 8A to Fig. 8C are diagrams illustrating an example in which target travel trajectories are generated assuming the direction of the vehicle. Fig. 8A is the same scene as the one in Fig. 7B, and the direction of the vehicle V is set to be outward (direction Y) in the lane width direction based on the lane center (continuous lateral target positions P5) of the adjacent lane 51, and is directed toward the lane boundary line L1. For this reason, when it is determined that the direction of the vehicle V is outward in the lane width direction based on the lane center (continuous lateral target positions P5) of the adjacent lane 51, the travel plan generation unit 14A assumes that the direction of the vehicle V is a direction along the lane center of the adjacent lane 51 (extension direction Z of the continuous lateral target positions P5), as shown in Fig. 8B. That is, the travel plan generation unit 14A replaces the direction Y7 of the vehicle V with a direction Y70. Alternatively, as shown in Fig. 8C, the travel plan generation unit 14A assumes that the direction of the vehicle V is inward in the lane width direction based on the lane center (continuous lateral target positions P5) of the adjacent lane 51. That is, the lane generation unit 14A replaces the direction Y2 of the vehicle V with a direction Y71. The travel plan generation unit 14A generates a target travel trajectory using the assumed direction of the vehicle V. Accordingly, any one of the target travel trajectories R70 and R71 in which there is no possibility of lane departure is generated instead of the target travel trajectory R7 in which there is a possibility of lane departure.

[0070] Next, processings executed by the vehicle travel control device 1 will be described. Fig. 9 is a flowchart illustrating an example of vehicle control processing of the vehicle travel control device 1A according to the present embodiment. Fig. For example, the control processing shown in Fig. 9 is executed when information indicating the start of automatic driving or driving assistance is input through an ON / OFF switch.

[0071] As in Fig. As shown in Figure 9, the travel plan generation unit 14A of the vehicle travel control device 1A determines whether operation information is acquired from the direction indicator 9 as an operation information determination processing (S20). In the operation information determination processing, if it is determined that the operation information is not acquired, the vehicle control processing shown in Figure 9 is executed. Fig. 9 is completed. On the other hand, in the operation information determination processing, when it is determined that the operation information is acquired, the processing proceeds to a target lane setting processing (S22).

[0072] The travel plan generation unit 14A sets a target lane based on the operation information as the target lane setting processing (S22). For example, if the operation information indicates a right turn signal, the travel plan generation unit 14A sets an adjacent lane located on the right side of the lane as the target lane. Alternatively, if the operation information indicates, for example, a left turn signal, the travel plan generation unit 14A sets an adjacent lane located on the left side of the lane as the target lane. When the target lane setting processing is completed, the processing proceeds to information acquisition processing (S30).

[0073] The subsequent processing steps S30 to S38 are the same as the processing steps S10 to S18 described in Fig. 5, except that the lateral target position is set in an adjacent lane.

[0074] As described above, the operation of the vehicle travel control device 1 shown in Fig. 9 is completed. By executing the procedure described in Fig.9, when the direction of the vehicle V in the vehicle width direction is outward based on the lane center (continuous lateral target positions P5) of the adjacent lane 51, the vehicle travel control device 1 assumes that the direction of the vehicle V is a direction along the lane center (continuous lateral target positions P5) of the adjacent lane 51 (extension direction Z of the continuous lateral target positions P5), or assumes that the direction of the vehicle V in the lane width direction is inward based on the lane center (continuous lateral target positions P5) of the adjacent lane 51. Therefore, when the vehicle V is caused to travel from the travel position P3 to the lateral target position P5 based on the target travel trajectory, it is possible to prevent the vehicle V from leaving the travel lane 50.

[0075] As described above, according to the vehicle travel control device 1A of the second embodiment, when a lane is changed from the traveling lane 50 to the adjacent lane 51, it is possible to prevent the vehicle from leaving the traveling lane 50 to the opposite side of the adjacent lane 51 which is a lane change target.

[0076] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above-mentioned embodiments. The present invention also includes changes and modifications of the above-mentioned embodiment based on the knowledge of those skilled in the art.

[0077] For example, in the aforementioned embodiment, an example was described in which the lane center position is set to the lateral target position. However, the lateral target position is not limited to the lane center position and may be a position offset from the lane center position. That is, the lane center of the target lane may have a width offset by an offset amount. Even in such a case, if the vehicle is caused to travel from the travel position to the lateral target position based on the target travel trajectory, it is possible to prevent the vehicle from leaving the travel lane.

[0078] Furthermore, in the above second embodiment, an example was presented in which the adjacent lane is set as the target lane based on the information about a direction indicator operation performed by a driver, but this is not limitative. For example, when the external situation of the vehicle V is recognized by the external situation recognition unit 11, and the travel plan generation unit 14 generates a travel plan for passing or overtaking a preceding vehicle based on the external situation, or when the travel plan generation unit 14 generates a travel plan for changing lanes based on the map database, an adjacent lane may be set as the target lane based on the travel plan.

Claims

[1] A vehicle travel control device (1, 1A) that causes a vehicle (V) to travel based on a target travel trajectory, comprising: an acquisition unit (13) configured to acquire a direction and a traveling position (3) of the vehicle (V); a trajectory generation unit (14) configured to generate a target travel trajectory from the travel position (3) to a lane center position of a target lane based on a direction of the vehicle (V), the travel position (3) and the lane center position of the target lane; a travel control unit (15) configured to cause the vehicle (V) to travel using the target travel trajectory; and a determination unit (14) configured to determine whether the direction of the vehicle (V) is outward in a lane width direction based on a lane center of the target lane, wherein, when it is determined by the determination unit (14) that the direction of the vehicle (V) is outward in the lane width direction based on the lane center of the target lane, the trajectory generation unit (14) generates the target travel trajectory on the assumption that the direction of the vehicle (V) is a direction along the lane center of the target lane or inward in the lane width direction based on the lane center of the target lane. [2] The vehicle travel control device (1, 1A) according to claim 1, wherein the trajectory generation unit (14) generates the target travel trajectory using a travel lane along which the vehicle (V) travels as the target lane. [3] The vehicle travel control device (1, 1A) according to claim 1, wherein the trajectory generation unit (14) generates the target travel trajectory using a lane adjacent to a traveling lane along which the vehicle (V) travels as the target lane.

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