Travel control method and travel control device

Abstract

To provide a travel control method and a travel control device that can prevent steering control from entering an abrupt steering state when an own vehicle travels from an own lane to an adjacent lane or a slip lane so as to avoid an obstacle on the own lane.SOLUTION: When it is determined to avoid an obstacle under avoidance control including steeling control in an avoidance direction for avoiding the obstacle, a travel path border line on an avoidance-directional side is expanded from a lane border line on the avoidance-directional side of an own lane to a border line on an avoidance-directional side of an adjacent lane or a slip lane; a first target track for traveling between a first steering start position on the travel path center line before the expansion between right and left travel path border lines, a first steering end position on a travel path center line after the expansion between the expanded travel path border line on the avoidance-directional side and a travel path border line in the opposite direction from the avoidance direction is generated; and the first steering end position is located on the travel-directional side of an own vehicle with respect to the intersection of the travel path center line between the travel path center line before the expansion and the travel path center line after the expansion, and the travel path center line after the expansion.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cruise control method and a cruise control device. [Background technology]

[0002] When an obstacle is detected on the path of the vehicle, a technology is known in which the line at the right end of the area in which the vehicle can travel is calculated as the right virtual lane, and the line at the left end of the area in which the vehicle can travel is calculated as the left virtual lane, based on the road width, the position and width of the obstacle, the position, width and speed of the oncoming vehicle, the vehicle speed, etc. (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-184563 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, for example, when the host vehicle can avoid an obstacle on the host lane by entering an adjacent lane or the like on the right side of the host lane, the right virtual lane is expanded from the lane boundary line on the right side of the host lane to the right lane boundary line of the adjacent lane or the like. In this case, if steering control of the host vehicle is performed using the center line between the right virtual lane and the left virtual lane as a target trajectory for obstacle avoidance, there is a problem that the steering control becomes abrupt when the right virtual lane is expanded to the right lane boundary line of the adjacent lane or the like at a steep angle relative to the lane boundary line on the right side of the host lane.

[0005] The problem that the present invention aims to solve is to provide a driving control method and a driving control device that can prevent sudden steering control when a vehicle moves from its own lane into an adjacent lane or a guidance strip in order to avoid an obstacle in its own lane. [Means for solving the problem]

[0006] The present invention solves the above problem by, when it is determined that an obstacle will be avoided through avoidance control including steering control in the avoidance direction to avoid an obstacle that obstructs the vehicle's travel, extending the lane boundary line on the avoidance direction side from the lane boundary line on the avoidance direction side of the vehicle's lane to the boundary line on the avoidance direction side of an adjacent lane or guidance strip, and generating a first target trajectory for traveling between a first steering start position on the pre-expanded lane center line between the left and right lane boundary lines before the expansion, and a first steering end position on the post-expanded lane center line between the expanded lane boundary line on the avoidance direction side and the lane boundary line in the opposite direction to the avoidance direction, and positioning the first steering end position on the side of the vehicle's travel direction relative to the intersection of the lane center line between the pre-expanded lane center line and the post-expanded lane center line. [Effects of the Invention]

[0007] According to the present invention, when a vehicle moves from its own lane into an adjacent lane or a guidance strip in order to avoid an obstacle in its own lane, it is possible to prevent the steering control from becoming abrupt. [Brief description of the drawings]

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

[0009] An embodiment of a cruise control device according to the present invention will be described with reference to the drawings. The configuration of the cruise control device according to this embodiment will be described with reference to FIG. 1. FIG. 1 is a block diagram showing a cruise control system 10 including a cruise control device according to the present invention. As shown in FIG. 1, the cruise control system 10 includes a detection device 1, a map database 2, a host vehicle information detection device 3, a navigation device 4, a vehicle control device 5, and a cruise control device 6. The detection device 1 includes an imaging device 11 and a distance measurement device 12. The host vehicle information detection device 3 includes a vehicle speed detection device 31, a steering angle detection device 32, and a host vehicle position detection device 33. The vehicle control device 5 includes a vehicle speed control device 51 and a steering control device 52. The devices included in the cruise control system 10 are connected via a CAN or other in-vehicle LAN and can exchange information with each other.

[0010] Cruise control system 10 according to the present invention can be applied not only to autonomous cruise control of a vehicle, but also to assisting a driver in manually driving the vehicle. When cruise control system 10 is applied to autonomous cruise control of a vehicle, it can autonomously control both speed control and steering control, or it can be applied to autonomously controlling one of speed control and steering control and manually controlling the other.

[0011] The detection device 1 is a sensor for detecting objects around the vehicle. Examples of objects include lane boundaries on roads, zebra strips, center lines, road markings, median strips, guardrails, curbs, highway sidewalls, road signs, traffic lights, crosswalks, construction sites, accident sites, and traffic restrictions. Objects also include automobiles (other vehicles) other than the vehicle itself, motorcycles, bicycles, and pedestrians. Objects also include obstacles that may affect the traveling of the vehicle itself. The detection device 1 acquires the position, attitude (orientation), and speed of the detected moving object.

[0012] The object is detected by, for example, the imaging device 11 and / or the distance measuring device 12. The detection results of the imaging device 11 and the distance measuring device 12 are acquired by the travel control device 6 at a predetermined time interval. The imaging device 11 is a device that recognizes an object around the host vehicle from an image, such as a camera. A plurality of imaging devices 11 may be provided on one vehicle.

[0013] The distance measuring device 12 is a device for calculating the relative distance and relative speed between the vehicle and the object, such as a laser radar, LIDAR, etc. A plurality of distance measuring devices 12 may be provided on one vehicle.

[0014] The map DB2 is a high-precision three-dimensional map in which a road structure including lane and road surface markings presenting the destination is described. The map DB2 is a database containing information used for generating a travel route and / or travel control. The map DB2 includes two-dimensional position information and / or three-dimensional position information at each map coordinate, road information at each map coordinate, lane boundary information, road attribute information, up / down information of the lane, lane identification information, connecting lane information, facility information, and their attribute information. The road information includes information such as road width, radius of curvature, roadside structures, road traffic regulations (speed limit, possibility of lane change), confluence points of the road, branch points, positions where the number of lanes increases or decreases, etc. The map DB2 is stored in a record medium provided in the travel control device 6, in-vehicle device, or server device in a readable state.

[0015] The map DB2 also includes information on lane boundaries that indicate the boundaries between the lane in which the vehicle is traveling and other lanes. Lane boundaries exist on both the left and right sides of the vehicle's traveling direction. The form of the lane boundaries is not particularly limited, and examples thereof include road markings and road structures. Examples of lane boundaries that are road markings include lane boundary lines and center lines. Examples of road boundary structures include medians, guardrails, curbs, and side walls of tunnels or expressways. Note that lane boundaries are preset in the map DB2 for points where lane boundaries cannot be clearly identified (for example, within intersections). The preset lane boundaries are imaginary road boundaries and are not actually existing road markings or road structures.

[0016] The host vehicle information detection device 3 is a device that detects information related to the state of the host vehicle. The state of the host vehicle includes the running speed, acceleration, steering angle, position, attitude, etc. of the host vehicle. The running speed and acceleration are detected using a vehicle speed detection device 31. The steering angle is detected using a steering angle detection device 32. The current position is calculated based on information acquired from a host vehicle position detection device 33. The attitude is detected using an inertial measurement unit. The cruise control device 6 acquires the detection results of these devices via an in-vehicle LAN as necessary.

[0017] The vehicle speed detection device 31 is not particularly limited as long as it is a sensor that can detect the vehicle's traveling speed, and a known sensor can be used. Similarly, the steering angle detection device 32 is not particularly limited as long as it is a sensor that can detect the vehicle's steering angle. Alternatively, the vehicle's traveling speed and steering angle may be acquired from the vehicle control device 5. The vehicle position detection device 33 is a positioning system that includes a GPS unit or the like, and is not particularly limited as long as it is a known sensor.

[0018] The navigation device 4 is a device that calculates a driving route from the current position of the host vehicle detected by the host vehicle position detection device 33 of the host vehicle information detection device 3 to the destination set by the driver with reference to the map DB2. The calculated driving route is output to the driving control device 6. The driving route is linear with the road on which the host vehicle travels, the direction (uphill / downhill), and the lane identified. The driving route includes information on the driving lane.

[0019] The vehicle control device 5 is an in-vehicle computer such as an electronic control unit (ECU), and electronically controls in-vehicle devices that regulate the driving of the vehicle. The vehicle control device 5 includes a vehicle speed control device 51 that controls the driving speed of the host vehicle and a steering control device 52 that controls the steering operation of the host vehicle.

[0020] The vehicle speed control device 51 controls a driving device such as an electric motor and / or an internal combustion engine, which is a driving power source, and an automatic transmission. The vehicle speed control device 51 autonomously controls the driving speed of the vehicle based on a control signal input from the driving control device 6.

[0021] The steering control device 52 controls the steering device. The steering control device 52 autonomously controls the operation of the steering device based on a control signal input from the driving control device 6 and using at least one of the detection result of the detection device 1, the map DB2, and the host vehicle information acquired by the host vehicle information detection device 3 so that the host vehicle travels while maintaining a predetermined lateral position (position in the left-right direction of the vehicle) with respect to the set target trajectory.

[0022] The driving control device 6 is a device that controls the driving of the host vehicle by controlling and cooperating the devices included in the driving control system 10. In the present embodiment, the driving control device 6 realizes an autonomous driving control function by the processor 7. The processor 7 is a computer including a ROM 72 in which a program is stored, a CPU 71 that is an operation circuit for functioning as the driving control device 6 by executing the program stored in the ROM 72, and a RAM 73 that functions as an accessible storage device.

[0023] The processor 7 sets left and right lane boundary lines of the lane on which the host vehicle is traveling, generates a target trajectory on the lane centerline between the left and right lane boundary lines, and causes the host vehicle to travel along the target trajectory. For example, the processor 7 sets left and right lane boundary lines on the left and right lane boundary lines of the host vehicle's lane on which the host vehicle is traveling, and causes the host vehicle to travel along the target trajectory generated on the lane centerline between the left and right lane boundary lines, i.e., on the lane centerline of the host vehicle. Furthermore, when it is necessary to avoid an obstacle that obstructs the host vehicle's travel in the host lane, the processor 7 generates a target trajectory for executing avoidance control, including steering control in the avoidance direction to avoid the obstacle. An obstacle is an object that cannot be avoided unless the host vehicle moves into an adjacent lane or a guidance strip to the left or right of the host lane. An obstacle is a stationary object on the host vehicle's lane, such as a parked vehicle or a construction sign.

[0024] The processor 7 according to this embodiment executes each function through cooperation between the software for realizing the above functions and the hardware described above. The processor 7 includes, as functional blocks, a vehicle position estimation unit 100, a traveling boundary acquisition unit 101, a surrounding information acquisition unit 102, an obstacle determination unit 103, an avoidance determination unit 104, a boundary setting unit 105, a trajectory generation unit 106, and a vehicle control unit 107.

[0025] The vehicle position estimation unit 100 estimates the position and attitude of the vehicle on a map. The vehicle position estimation unit 100 estimates the current position and attitude of the vehicle on a map based on map information acquired from the map DB 2 and the position and attitude acquired from the vehicle information detection device 3. Various methods for estimating the vehicle's position have been proposed, but in the present invention, the method is not limited as long as it is possible to estimate the position and attitude of the vehicle.

[0026] The traveling boundary acquisition unit 101 acquires lane information around the host vehicle. For example, the traveling boundary acquisition unit 101 acquires lane information about the host lane in which the host vehicle is traveling. Furthermore, when there is an obstacle such as a parked vehicle in the host lane, the traveling boundary acquisition unit 101 acquires lane information about an adjacent lane or a guidance strip adjacent to the host lane. The lane information includes the position of the lane and the width of the lane. The traveling boundary acquisition unit 101 first acquires the road structure around the host vehicle from the map DB2 based on the position and attitude of the host vehicle estimated by the host vehicle position estimation unit 100. For example, if an adjacent lane or a guidance strip exists, the traveling boundary acquisition unit 101 acquires lane information including the lane boundary lines of the adjacent lane or the boundary lines of the guidance strip from the map DB2. Furthermore, the traveling boundary acquisition unit 101 may acquire lane information including the lane boundary lines of the host lane, the lane boundary lines of the adjacent lane, or the boundary lines of the guidance strip from an image around the host vehicle captured by the imaging device 11.

[0027] The surrounding information acquisition unit 102 acquires surrounding traffic condition information related to the traffic conditions around the vehicle based on the detection information detected by the detection device 1. The surrounding traffic condition information includes, for example, surrounding object information related to objects around the vehicle. The surrounding object information includes the position, posture, and speed of the surrounding object. For example, the surrounding information acquisition unit 102 acquires surrounding traffic condition information related to the traffic conditions in the traveling direction of the vehicle's lane. The surrounding information acquisition unit 102 also acquires surrounding traffic condition information related to the traffic conditions in adjacent lanes or guidance zones.

[0028] The obstacle determination unit 103 determines whether or not there is an obstacle in the current lane that obstructs the travel of the current vehicle, based on the lane information and the surrounding traffic condition information. For example, the obstacle determination unit 103 determines whether or not there is an object in the current lane that satisfies the conditions described below, based on the positions of the left and right boundary lines of the current lane, the width of the current lane, which are included in the lane information of the current lane, and the positions and states of surrounding objects, which are included in the surrounding traffic condition information. If there is an object in the current lane that satisfies the conditions described below, the obstacle determination unit 103 identifies the object as an obstacle and determines that there is an obstacle in the current lane. Furthermore, if there is no object in the current lane that satisfies the conditions, the obstacle determination unit 103 determines that there is no obstacle in the current lane.

[0029] If it is determined that an obstacle is present, the obstacle determination unit 103 determines whether the obstacle is closer to the left or right on the vehicle lane based on the positions of the boundary line of the vehicle's lane and the position of the obstacle. For example, the obstacle determination unit 103 determines the direction of the lane boundary line on the left or right of the vehicle's lane that is closer to the obstacle as the direction in which the obstacle is closer on the vehicle lane. The obstacle determination unit 103 outputs a flag indicating the presence of an obstacle, the left or right direction in which the obstacle is closer on the vehicle's lane, and the distance from the vehicle's position to the obstacle. If it is determined that no obstacle is present, the obstacle determination unit 103 outputs a flag indicating that no obstacle is present.

[0030] The conditions for determining whether an obstacle is present are, for example, that an object exists in the direction of travel of the own vehicle's lane and that the object is stopped. Alternatively, the conditions for determining whether an obstacle is present may be that the following three conditions are satisfied: the first condition is that an object exists in the direction of travel of the own vehicle's lane and that the object is stopped; the second condition is that the object is located to the left or right of the center of the own vehicle's lane by a predetermined value or more; and the third condition is that the length obtained by subtracting the width of the object from the width of the own vehicle's lane is equal to or less than a predetermined length. The predetermined length is the width length necessary for the own vehicle to pass the side of the object in the own vehicle's lane.

[0031] The avoidance determination unit 104 determines, based on the lane information, whether the host vehicle will avoid the obstacle by steering control in the avoidance direction to avoid the obstacle. For example, when the obstacle determination unit 103 determines that there is an obstacle, the avoidance determination unit 104 determines, based on the lane information acquired by the driving boundary acquisition unit 101, whether the host vehicle will avoid the obstacle. When there is either an adjacent lane or a guidance strip in the avoidance direction relative to the host lane, in which the host vehicle can travel, the avoidance determination unit 104 determines that the host vehicle will avoid the obstacle in the avoidance direction. Furthermore, when there is neither an adjacent lane nor a guidance strip in the avoidance direction relative to the host lane, the avoidance determination unit 104 determines that the host vehicle will not avoid the obstacle. In this case, the host vehicle stops in front of the obstacle. Then, for example, the driving control of the host vehicle is switched to manual driving by the driver.

[0032] Furthermore, the avoidance determination unit 104 may determine whether or not the host vehicle will avoid an obstacle based on lane information and surrounding traffic condition information. For example, when an adjacent lane or guidance strip is present in the avoidance direction, the avoidance determination unit 104 determines, based on surrounding object information, whether or not there is an obstacle on the adjacent lane or guidance strip that may hinder avoidance control. Examples of obstacles include parked vehicles and oncoming vehicles. When there is no obstacle on the adjacent lane or guidance strip, the avoidance determination unit 104 determines that the host vehicle will avoid the obstacle. When there is an obstacle on the adjacent lane or guidance strip, the avoidance determination unit 104 determines that the host vehicle will not avoid the obstacle.

[0033] Furthermore, when the obstacle determination unit 103 determines that there is an obstacle, the avoidance determination unit 104 may specify, as the avoidance direction, the direction opposite to the direction in which the obstacle is approaching on the own vehicle lane. Then, the avoidance determination unit 104 determines whether the host vehicle will avoid the obstacle, using the direction opposite to the direction in which the obstacle is approaching on the own vehicle lane as the avoidance direction. The avoidance determination unit 104 determines that the host vehicle will avoid the obstacle when there is either an adjacent lane or a guidance strip on the own vehicle that can be traveled on in the direction opposite to the direction in which the obstacle is approaching on the own vehicle lane. The avoidance determination unit 104 determines that the host vehicle will not avoid the obstacle when there is neither an adjacent lane or a guidance strip on the own vehicle that can be traveled on in the direction opposite to the direction in which the obstacle is approaching on the own vehicle lane.

[0034] The boundary setting unit 105 sets left and right lane boundary lines of the lane on which the host vehicle is traveling. In this embodiment, the boundary setting unit 105 sets lane boundary lines defined by lane boundary lines and lane boundary lines defined by obstacles. For example, the boundary setting unit 105 sets the left and right lane boundary lines to the left and right lane boundary lines of the host lane. Furthermore, when the avoidance determination unit 104 determines that the host vehicle will avoid an obstacle on the host lane, the boundary setting unit 105 sets the lane boundary line on the avoidance direction side to the lane boundary line on the avoidance direction side of an adjacent lane or the boundary line on the avoidance direction side of a guidance strip. In other words, when performing avoidance control, the boundary setting unit 105 extends the lane boundary line on the avoidance direction side from the lane boundary line on the avoidance direction side of the host lane to the boundary line on the avoidance direction side of an adjacent lane or a guidance strip. In this embodiment, the lane boundary line on the avoidance direction side before expansion is set to the lane boundary line on the avoidance direction side of the own lane, and the lane boundary line on the avoidance direction side after expansion is set to the lane boundary line on the avoidance direction side of the adjacent lane or guidance strip.

[0035] Adjacent lanes include adjacent lanes in the same direction as the traveling direction of the own vehicle lane and adjacent lanes in the opposite direction to the traveling direction of the own vehicle lane (oncoming lane). For example, if the road on which the own vehicle is traveling has two lanes in each direction and traffic flows in both directions, the adjacent lane to the own vehicle lane is a lane in the same direction as the traveling direction of the own vehicle lane. Also, for example, if the road on which the own vehicle is traveling has one lane in each direction and traffic flows in both directions, the adjacent lane to the own vehicle lane is an oncoming lane.

[0036] The lane boundary line expansion method will be explained using Fig. 2. Fig. 2 is a diagram showing a situation where a parked vehicle exists as an obstacle in the own lane. Fig. 2 shows a situation where a parked vehicle V2 exists in the own lane L1 in which the own vehicle V1 is traveling, and the own vehicle V1 performs avoidance control to avoid the parked vehicle V2 by turning the direction of the adjacent lane L2 as the avoidance direction.

[0037] The boundary setting unit 105 first sets an avoidance start position Pas and an avoidance end position Pae of an avoidance section S for executing avoidance control. The avoidance section S is a section from the avoidance start position Pas to the avoidance end position Pae along the traveling direction of the host vehicle V1. The avoidance start position Pas is a position on the traveling center line of the host lane L1, and is the position where the host vehicle V1 starts avoidance control. The avoidance end position Pae is a position on the traveling center line of the host lane L1, and is the position where the host vehicle V1 ends avoidance control and starts traveling along the traveling center line of the host lane L1.

[0038] The boundary setting unit 105 sets, for example, an avoidance start position Pas at a position a predetermined avoidance distance away from the position of the parked vehicle V2 in the direction opposite to the traveling direction of the host vehicle V1, and sets an avoidance end position Pae at a position a predetermined avoidance distance away from the position of the parked vehicle V2 in the traveling direction of the host vehicle V1. The predetermined avoidance distance is a distance calculated by multiplying the vehicle speed of the host vehicle by a predetermined time period.

[0039] Next, the boundary setting unit 105 sets a lane boundary line on the avoidance direction side in the avoidance section. In this embodiment, the avoidance section is composed of an expanded section and an intermediate section. The lane boundary line on the avoidance direction side in the expanded section is a lane boundary line on the avoidance direction side after expansion, and is set as a boundary line on the avoidance direction side of an adjacent lane or guidance strip. The intermediate section is a section from the avoidance start position to the start position of the expanded section, and a section from the end position of the expanded section to the avoidance end position. The lane boundary line on the avoidance direction side in the intermediate section, which starts from the avoidance start position, connects the lane boundary line on the avoidance direction side before expansion and the lane boundary line on the avoidance direction side after expansion. In other words, the lane boundary line in the intermediate section is a line connecting the lane boundary line on the avoidance direction side of the vehicle lane and the boundary line on the avoidance direction side of an adjacent lane or guidance strip.

[0040] In the example of FIG. 2, the lane boundary lines before expansion are set to the left and right lane boundary lines of the host vehicle lane L1 on the front side in the traveling direction from the avoidance start position Pas. Further, the avoidance section S is composed of an intermediate section S1, an expansion section S2, and an intermediate section S3. The boundary setting unit 105 sets the avoidance direction side lane boundary line LR to the boundary line on the avoidance direction side of the adjacent lane L2 in the expansion section S2. The boundary setting unit 105 sets the avoidance direction side lane boundary line LR on the line connecting the lane boundary line on the avoidance direction side of the host vehicle lane L1 and the boundary line on the avoidance direction side of the adjacent lane L2 in the intermediate section S1. The boundary setting unit 105 sets the avoidance direction side boundary line LR on the line connecting the lane boundary line on the avoidance direction side of the adjacent lane L2 and the lane boundary line on the avoidance direction side of the host vehicle lane L1 in the intermediate section S3.

[0041] For example, the boundary setting unit 105 sets the line connecting the lane marker on the lane boundary line on the avoidance direction side of the host vehicle lane and the lane marker on the boundary line on the avoidance direction side of the adjacent lane or the flow guiding zone as the avoidance direction side lane boundary line in the intermediate section. Further, the boundary setting unit 105 sets the avoidance direction side lane boundary line in the expansion section on the lane marker on the boundary line on the avoidance direction side of the adjacent lane or the flow guiding zone.

[0042] The trajectory generation unit 106 generates a target trajectory for the host vehicle to travel. In the present embodiment, the host vehicle travels along the generated target trajectory. The trajectory generation unit 106 generates the target trajectory along the center line of the lane between the left and right lane boundary lines. For example, when the host vehicle travels along the host vehicle lane, since the left and right lane boundary lines are set to the left and right lane boundary lines of the host vehicle lane by the boundary setting unit 105, the trajectory generation unit 106 generates the target trajectory along the center line of the lane between the left and right lane boundary lines of the host vehicle lane.

[0043] Furthermore, when the avoidance determination unit 104 determines that an obstacle on the own lane is to be avoided, the trajectory generation unit 106 generates a target trajectory for executing avoidance control. The target trajectory for executing avoidance control is a trajectory from the avoidance start position to the avoidance end position, and is made up of an avoidance start steering section in which steering control is performed in the avoidance direction, a side running section in which control is performed to run along the side of the obstacle, and an avoidance end steering section in which steering control is performed to return to the own lane.

[0044] Here, the avoidance control will be explained. In this embodiment, the avoidance control is divided into three types of control: steering control in the avoidance direction, control to travel to the side of the obstacle, and steering control to return to the vehicle's own lane. In the avoidance start steering section, the cruise control device 6 executes steering control to move the lateral position, which indicates the vehicle's position in the vehicle width direction, from an avoidance start position on the lane center line of the vehicle's own lane in the avoidance direction. In the side running section, the cruise control device 6 executes driving control to cause the vehicle to travel to the side of the obstacle along the post-expansion lane center line between the left and right lane boundary lines after expansion. In the avoidance end steering section, the cruise control device 6 executes steering control to move the lateral position of the vehicle from the post-expansion lane center line to an avoidance end position on the lane center line of the vehicle's own lane.

[0045] The trajectory generating unit 106 generates a target trajectory for the avoidance start steering section. The target trajectory for the avoidance start steering section is a trajectory along which the host vehicle travels by steering control between a steering start position on a pre-expansion track centerline between the left and right lane boundary lines before expansion and a steering end position on a post-expansion track centerline between the expanded lane boundary line on the avoidance direction side and the lane boundary line in the opposite direction to the avoidance direction. The steering end position is located on the side of the host vehicle's traveling direction relative to the intersection of the track centerline connecting the pre-expansion track centerline and the post-expansion track centerline and the post-expansion track centerline. The pre-expansion track centerline is the track centerline between the left and right lane boundary lines before expansion, i.e., the track centerline between the left and right lane boundary lines of the host lane. The post-expansion track centerline is the track centerline between the left and right lane boundary lines after expansion, i.e., the track centerline between the expanded lane boundary line on the avoidance direction side and the lane boundary line in the opposite direction to the avoidance direction.

[0046] The trajectory generating unit 106 sets the avoidance start position of the avoidance section as the steering start position in the avoidance start steering section, and sets the steering end position in the avoidance start steering section at a position that is a predetermined distance away from the avoidance start position in the traveling direction of the host vehicle. The predetermined distance is longer than the distance in the traveling direction of the intermediate section. The predetermined distance may also be shorter than the distance between the avoidance start position and the position of the obstacle on the host vehicle lane. The trajectory generating unit 106 sets the predetermined distance, and sets the avoidance start steering section by setting the set predetermined distance as the distance of the avoidance start steering section.

[0047] For example, the trajectory generating unit 106 sets the predetermined distance according to the expansion width of the length in the lane width direction between the left and right lane boundary lines. The expansion width is the difference between the length in the lane width direction between the expanded lane boundary line on the avoidance direction side and the lane boundary line in the direction opposite to the avoidance direction, and the length in the lane width direction between the left and right lane boundary lines before expansion. The trajectory generating unit 106 sets the predetermined distance longer the greater the expansion width, and sets the predetermined distance shorter the smaller the expansion width. In this embodiment, by setting the length of the avoidance start steering section longer than the distance of the intermediate section according to the expansion width, the curvature during turning by steering control can be made smaller than when the host vehicle travels on the lane centerline between the left and right lane boundary lines in the intermediate section.

[0048] Furthermore, the trajectory generating unit 106 may set the predetermined distance to be longer as the vehicle speed of the host vehicle is higher, and may set the distance of the avoidance start steering section to be shorter as the vehicle speed of the host vehicle is lower. When the host vehicle is steered along the target trajectory, the lateral acceleration caused by the steering control is calculated by the following equation (1) based on the curvature during turning due to the steering control and the vehicle speed of the host vehicle.

number

[0049] In this embodiment, an upper limit value is set for the lateral acceleration Ay, and a predetermined distance is set such that the value of the curvature is such that the lateral acceleration Ay does not exceed the upper limit value. For example, the trajectory generation unit 106 acquires the vehicle speed of the host vehicle, and based on the upper limit value of the lateral acceleration and the vehicle speed of the host vehicle, sets the value of the curvature so that the lateral acceleration does not exceed the upper limit value. Then, the trajectory generation unit 106 sets the value of the predetermined distance so as to realize the set value of the curvature. Thereby, even when an upper limit value is set for the lateral acceleration, unnecessary deceleration during steering control can be prevented from occurring.

[0050] After setting the avoidance start steering section, the trajectory generation unit 106 generates a target trajectory in the avoidance start steering section. The trajectory generation unit 106 uses the avoidance start position on the pre-expansion travel center line as the steering start position, and generates, as the target trajectory in the avoidance start steering section, a trajectory connecting the avoidance start position and the steering end position on the post-expansion travel center line.

[0051] The method for generating the target trajectory in the avoidance start steering section will be described with reference to FIG. 2. The trajectory generation unit 106 sets an avoidance start steering section SA1 starting from the avoidance start position Pas, and specifies the steering end position Pse of the avoidance start steering section SA1 on the post-expansion travel center line Lb3. At this time, the distance of the avoidance start steering section SA1 is longer than the distance of the intermediate section S1, and the steering end position Pse is located on the traveling direction side with respect to the intersection point Pb between the travel center line Lb2 connecting between the pre-expansion travel center line Lb1 and the post-expansion travel center line Lb3 and the post-expansion travel center line Lb3. The pre-expansion travel center line Lb1 is the travel center line between the left and right lane boundary lines of the host lane L1 on the front side in the traveling direction with respect to the avoidance start position Pas. The post-expansion travel center line Lb3 is the travel center line between the left and right travel boundary lines in the expansion section S2 of the avoidance section S, that is, the travel center line between the lane boundary line in the direction opposite to the avoidance direction of the host lane L1 and the lane boundary line on the avoidance direction side of the adjacent lane L2. Then, the trajectory generation unit 106 uses the avoidance start position Pas as the steering start position, and generates, as the target trajectory Ls1 in the avoidance start steering section SA1, a trajectory connecting the avoidance start position Pas and the steering end position Pse.

[0052] In this embodiment, an avoidance start steering section SA1 that is longer than the distance in the traveling direction of the intermediate section S1 is set, and a target trajectory Ls1 in the avoidance start steering section SA1 is generated, thereby preventing the steering control in the avoidance direction from becoming a sharp steering in response to the expansion of the lane boundary line. When the target trajectory is generated on the center line of the lane between the lane boundary lines, the target trajectory in the intermediate section S1 is a trajectory along the center line Lb2 of the lane between the left and right lane boundary lines in the avoidance section S1 as shown in FIG. 2. In this case, if the lane boundary line on the avoidance direction side in the intermediate section expands at a sharp angle with respect to the boundary line of the own lane, the steering control in the avoidance direction may become a sharp steering.

[0053] On the other hand, in this embodiment, since the target trajectory Ls1 is generated based on the avoidance start steering section SA1, in the target trajectory Ls1 in the avoidance start steering section SA1, the rate of change of the position of the host vehicle in the lane width direction is smaller than the rate of change of the position of the host vehicle in the lane width direction traveling on the center line Lb2 of the lane in the intermediate section S1. Thereby, it is possible to prevent the steering control in the avoidance direction from becoming a sharp steering.

[0054] The trajectory generation unit 106 generates a target trajectory in the lateral traveling section. For example, the lateral traveling section is a section between the steering end position of the avoidance start steering section and the steering start position of the avoidance end steering section. The trajectory generation unit 106 generates a target trajectory in the lateral traveling section along the expanded center line of the lane. In the example of FIG. 2, the trajectory generation unit 106 generates a target trajectory Ls2 in the lateral traveling section on the expanded center line Lb3 between the steering end position Pse of the avoidance start steering section SA1 and the steering start position Pss of the avoidance end steering section SA3.

[0055] The trajectory generation unit 106 generates a target trajectory in the avoidance end steering section. The target trajectory in the avoidance end steering section is a trajectory for the host vehicle to travel by steering control between the steering start position of the avoidance end steering section on the expanded center line of the lane and the avoidance end position on the center line of the lane of the own lane after the avoidance control. The center line of the lane of the own lane after the avoidance control is the center line of the lane of the own lane on the traveling direction side from the avoidance end position.

[0056] The trajectory generation unit 106 sets the steering start position of the avoidance end steering section at a position that is a predetermined distance away from the avoidance end position in the direction opposite to the traveling direction. The method for setting the predetermined distance is the same as the method for setting the predetermined distance in the avoidance start steering section. That is, the trajectory generation unit 106 sets a predetermined distance, and sets the avoidance end steering section with the set predetermined distance as the distance of the avoidance end steering section. After setting the avoidance end steering section, the trajectory generation unit 106 generates a target trajectory in the avoidance end steering section. The trajectory generation unit 106 generates, as the target trajectory in the avoidance end steering section, a trajectory connecting the steering start position of the avoidance end steering section on the extended center line of the road and the avoidance end position on the center line of the own lane.

[0057] The method for generating the target trajectory in the avoidance end steering section will be described with reference to FIG. 2. The trajectory generation unit 106 sets an avoidance end steering section SA3 starting from the avoidance end position Pae, and specifies the steering start position Pss of the avoidance end steering section SA3 on the extended center line Lb3 of the road. Then, the trajectory generation unit 106 generates, as the target trajectory Ls3 in the avoidance end steering section SA3, a trajectory connecting the steering start position Pss of the avoidance end steering section SA3 and the avoidance end position Pae. In the present embodiment, by setting an avoidance end steering section SA3 that is longer than the distance in the traveling direction of the intermediate section S3 starting from the avoidance end position Pae and generating the target trajectory Ls3 in the avoidance end steering section SA3, it is possible to prevent the steering control for returning to the own lane after the avoidance control from becoming a sudden steering in accordance with the return of the road boundary line to the lane boundary line of the own lane.

[0058] Furthermore, in this embodiment, the timing at which the trajectory generation unit 106 sets the avoidance start steering section and the timing at which the trajectory generation unit 106 sets the avoidance end steering section may be the same or different. For example, the trajectory generation unit 106 may set the avoidance start steering section before the start of avoidance, and set the avoidance end steering section during avoidance. In this case, for example, since the predetermined distance is calculated based on the vehicle speed of the host vehicle at each timing, if the vehicle speed of the host vehicle at each timing is different, the distance of the avoidance start steering section and the distance of the avoidance end steering section will be different lengths.

[0059] Furthermore, in this embodiment, when the host vehicle approaches an obstacle while traveling on a target trajectory in a side traveling section, i.e., on the expanded post-travel path center line in the side traveling section, a target trajectory is generated for the host vehicle to travel to the side of the obstacle at a predetermined offset distance from the obstacle. Due to limitations in the host vehicle's sensor performance, it is difficult to generate a target trajectory based on the accurate position of the obstacle until the host vehicle approaches the obstacle. Therefore, for example, even if steering control is performed in the avoidance direction along the target trajectory in the avoidance start steering section, the host vehicle may not move lateral to the obstacle in the avoidance direction sufficiently. In such cases, the host vehicle approaches the obstacle while traveling along the expanded post-travel path center line. In such cases, in this embodiment, a target trajectory for traveling to the side of the obstacle at a sufficient distance from the obstacle is generated based on the position of the obstacle in the approach section where the host vehicle approaches the obstacle.

[0060] The boundary setting unit 105 sets an area including an obstacle as a no-drive area, and sets a lane boundary line on the opposite side of the avoidance direction as the boundary line of the no-drive area. For example, as shown in Fig. 3, based on the position of the parked vehicle V2, a lane boundary line LL on the opposite side of the avoidance direction is set as the boundary line of the no-drive area PA so that the host vehicle V1 can drive without approaching the parked vehicle V2.

[0061] The trajectory generating unit 106 sets a lane boundary line on the side opposite to the avoidance direction based on the position of the obstacle, and then generates a target trajectory in the approach section so that the host vehicle travels at a position a predetermined offset distance from the lane boundary line on the side opposite to the avoidance direction. For example, the predetermined offset distance is the distance between the lane centerline between the expanded lane boundary line on the side opposite to the avoidance direction and the lane boundary line on the side opposite to the avoidance direction set based on the position of the obstacle, and the lane boundary line on the side opposite to the avoidance direction set based on the position of the obstacle.

[0062] In this embodiment, the trajectory generating unit 106 determines whether the distance between the post-expansion track center line and the boundary line of the travel-prohibited area is equal to or less than a predetermined offset distance. That is, the trajectory generating unit 106 determines whether the distance between the target track in the side travel section and the boundary line of the travel-prohibited area is equal to or less than a predetermined offset distance. Then, based on the determination result, the trajectory generating unit 106 identifies an approaching section in which the distance between the post-expansion track center line and the boundary line of the travel-prohibited area is equal to or less than the predetermined offset distance. Then, if there is an approaching section, the trajectory generating unit 106 sets a target trajectory for the approaching section.

[0063] A method for generating a target trajectory in the approaching section will be described with reference to Fig. 3. Similar to Fig. 2, Fig. 3 shows a scene in which the host vehicle V1 traveling in the host vehicle lane L1 avoids a parked vehicle V2. In Fig. 3, a lane boundary line LL in the opposite direction to the avoidance direction is set along the boundary line of the no-travel area PA that includes the parked vehicle V2. The trajectory generating unit 106 generates a target trajectory Lc in the approaching section Sc at a position a predetermined offset distance Do away from the lane boundary line LL in the opposite direction to the avoidance direction.

[0064] In this embodiment, a target trajectory in the side driving section is generated, and when the host vehicle traveling on the target trajectory in the side driving section approaches an obstacle, a new target trajectory in the approach section is generated. However, this is not limited to this, and when the host vehicle traveling on the target trajectory in the avoidance start steering section approaches an obstacle, a new target trajectory in the approach section may be generated.

[0065] The vehicle control unit 107 controls the host vehicle to travel along the target trajectory. Specifically, when the host vehicle travels on the host lane, the vehicle control unit 107 controls the host vehicle to travel along a target trajectory generated on the center line of the host lane. Furthermore, when performing avoidance control, the vehicle control unit 107 controls the host vehicle to travel along the target trajectory in the avoidance section. That is, the vehicle control unit 107 starts steering control of the host vehicle in the avoidance direction from the avoidance start position, and performs steering control to move the host vehicle within the trajectory that extends to the adjacent lane or guidance strip to the avoidance end position. The vehicle control unit 107 calculates a target vehicle speed and a target steering angle for traveling along the target trajectory, and generates a control signal for traveling the host vehicle based on the calculated target vehicle speed and target steering angle. The generated control signal is output to the vehicle control device 5.

[0066] In this embodiment, the vehicle control unit 107 executes first steering control as control corresponding to the expansion of the lane boundary line on the avoidance direction side, so that the host vehicle travels along a target trajectory in the avoidance start steering section. Then, when the host vehicle approaches an obstacle, the vehicle control unit 107 executes second steering control as control corresponding to the lane boundary line determined by the position of the obstacle, so that the host vehicle travels along the target trajectory in the approach section. In this embodiment, even if two-stage steering control in the avoidance direction is performed, by smoothing the target trajectory in the avoidance start steering section, it is possible to prevent the first steering control from becoming abrupt steering, and to achieve two-stage steering control in the avoidance direction that does not feel strange to the occupants of the host vehicle.

[0067] Next, an example of the procedure for cruise control executed by the cruise control device 6 will be described. FIG. 4 is a flowchart showing a control flow for executing cruise control by the cruise control device 6. In this embodiment, when the host vehicle starts traveling, the control flow starts from step S1. The cruise control device 6 sets left and right road boundary lines on the left and right lane boundary lines of the host vehicle's lane, and generates a target trajectory on the center line of the host lane. The host vehicle is controlled to travel along the target trajectory. In this embodiment, if avoidance control cannot be started and the cruise control flow ends, cruise control switches to manual driving by the driver.

[0068] In step S1, processor 7 acquires lane information around the host vehicle. In step S2, processor 7 acquires surrounding traffic condition information around the host vehicle. In step S3, processor 7 determines whether or not there is an obstacle in the host lane based on the host lane information and the surrounding traffic condition information. If it is determined that there is an obstacle in the host lane, processor 7 proceeds to step S4. If it is determined that there is no obstacle in the host lane, processor 7 returns to step S1 and repeats the control flow thereafter. In step S4, processor 7 determines an avoidance direction to avoid the obstacle. For example, processor 7 determines the avoidance direction to be the opposite direction to the direction in which the obstacle is approaching on the host lane.

[0069] In step S5, processor 7 determines whether to avoid the obstacle. For example, based on lane information, processor 7 determines to avoid the obstacle if an adjacent lane or guidance strip on which the host vehicle can travel to avoid the obstacle exists on the avoidance direction side. If it is determined that the obstacle will be avoided, processor 7 proceeds to step S6. If it is determined that the obstacle will not be avoided, processor 7 terminates the avoidance control. In step S6, processor 7 sets an avoidance section for performing avoidance control. For example, processor 7 sets an avoidance start position and an avoidance end position of the avoidance section. In step S7, processor 7 extends the lane boundary line on the avoidance direction side from the lane boundary line on the avoidance direction side of the host lane to the boundary line of the adjacent lane or guidance strip on the avoidance direction side.

[0070] In step S8, the processor 7 generates a target trajectory in the avoidance section. For example, the processor 7 generates a target trajectory in the avoidance start steering section, a target trajectory in the lateral driving section, and a target trajectory in the avoidance end steering section, and integrates these target trajectories to generate a target trajectory in the avoidance section. The target trajectory in the avoidance start steering section is a trajectory from the avoidance start position on the driving center line of the own lane to the steering end position on the extended driving center line. Also, the target trajectory in the lateral driving section is a trajectory along the extended driving center line. Further, the target trajectory in the avoidance end steering section is a trajectory from the steering start position on the extended driving center line to the avoidance end position on the driving center line of the own lane.

[0071] In step S9, the processor 7 controls the running of the host vehicle along the target trajectory. In step S10, the processor 7 determines whether the host vehicle approaches an obstacle while the host vehicle is running along the target trajectory generated in step S8. If it is determined that the host vehicle approaches the obstacle, the processor 7 proceeds to step S11. If it is determined that the host vehicle does not approach the obstacle, the processor 7 proceeds to step S13. In step S11, the processor 7 generates a target trajectory for running along the side of the obstacle at a predetermined offset distance from the obstacle. In step S12, the processor 7 controls the running of the host vehicle along the target trajectory generated in step S11.

[0072] In step S13, the processor 7 determines whether the avoidance control has ended. For example, based on the position of the host vehicle and the avoidance end position, the processor 7 determines that the avoidance control has ended when the host vehicle reaches the avoidance end position. When the host vehicle has not reached the avoidance end position, the processor 7 determines that the avoidance control has not ended. If it is determined that the avoidance control has ended, the processor 7 ends the control flow. If it is determined that the avoidance control has not ended, the processor 7 returns to step S10 and repeats the control flow hereinafter.

[0073] As described above, in this embodiment, a driving control method is executed by a processor that sets left and right lane boundary lines of a road on which the host vehicle is traveling as left and right lane boundary lines of the host vehicle's lane, generates a target trajectory on a road center line between the lane boundary lines, and causes the host vehicle to travel along the target trajectory, wherein the processor acquires lane information around the host vehicle, acquires surrounding traffic condition information relating to the traffic conditions around the host vehicle, and, based on the lane information and surrounding traffic condition information, when an obstacle that obstructs the traveling of the host vehicle in the host vehicle's lane is detected, determines whether or not to avoid the obstacle by avoidance control including steering control in the avoidance direction to avoid the obstacle, If it is determined that the obstacle will be avoided, the lane boundary line on the avoidance direction side is expanded from the lane boundary line on the avoidance direction side of the own lane to the boundary line on the avoidance direction side of an adjacent lane adjacent to the own lane or a guidance strip, and a trajectory for the own vehicle to travel by steering control between a first steering start position on the pre-expansion lane center line between the left and right lane boundary lines before the expansion and a first steering end position on the post-expansion lane center line between the expanded lane boundary line on the avoidance direction side and a lane boundary line in the opposite direction to the avoidance direction is generated as a first target trajectory, the first steering end position being located on the side of the traveling direction of the own vehicle relative to the intersection of the lane center line connecting the pre-expansion lane center line and the post-expansion lane center line and the post-expansion lane center line. This prevents sudden steering control when the own vehicle travels from the own lane to travel into an adjacent lane or a guidance strip to avoid an obstacle on the own lane.

[0074] In this embodiment, the processor sets the first steering end position at a predetermined distance in the traveling direction from the first steering start position, and the predetermined distance is longer as the expansion width, which is the difference between the length in the lane width direction between the expanded lane boundary line in the avoidance direction and the lane boundary line in the opposite direction to the avoidance direction, and the length in the lane width direction between the left and right lane boundary lines before expansion, is larger. This makes it possible to prevent the curvature during turning due to steering control from increasing due to an increase in the expansion width.

[0075] Also, in the present embodiment, the processor sets a first steering end position at a position a predetermined distance away from the first steering start position in the traveling direction, and the predetermined distance is longer as the vehicle speed of the host vehicle is higher. Thereby, it is possible to suppress an increase in lateral acceleration during avoidance control by suppressing an increase in the curvature during turning by steering control.

[0076] Also, in the present embodiment, when the host vehicle approaches an obstacle while traveling on the extended center line of the lane, the processor generates a second target trajectory for the host vehicle to avoid the obstacle. Thereby, when the host vehicle approaches an obstacle, it can travel so as to avoid the obstacle.

[0077] Also, in the present embodiment, the processor sets a region including the obstacle as a non-drivable region, sets a boundary line on the side opposite to the avoidance direction on the boundary line of the non-drivable region, and generates a second target trajectory so that the host vehicle travels at a position a predetermined offset distance away from the boundary line on the side opposite to the avoidance direction. Thereby, it is possible to travel on the side of the obstacle while ensuring a sufficient lateral distance from the obstacle.

[0078] Also, in the present embodiment, when there is a proximity section where the distance between the extended center line of the lane and the boundary line of the non-drivable region is equal to or less than a predetermined offset distance, the processor sets the target trajectory in the proximity section as the second target trajectory. Thereby, it is possible to prevent the host vehicle traveling on the target trajectory according to the extension of the lane boundary from approaching the obstacle.

[0079] Also, in the present embodiment, the processor executes first steering control so that the host vehicle travels along the first target trajectory, and executes second steering control so that the host vehicle travels along the second target trajectory. Thereby, the behavior of the host vehicle by two-stage avoidance control can be made into a behavior without a sense of strangeness.

[0080] Also, in the present embodiment, the processor sets an avoidance start position and an avoidance end position of an avoidance section for performing avoidance control. Taking the avoidance start position as the first steering start position, a first steering end position is set at a position a predetermined distance away from the avoidance start position in the traveling direction. A third steering start position is set at a position a predetermined distance away from the avoidance end position in the direction opposite to the traveling direction. A trajectory for the host vehicle to travel by steering control between the third steering start position on the extended center line of the lane and the avoidance end position on the center line of the host lane is generated as the third target trajectory. The predetermined distance from the avoidance start position to the first steering end position and the predetermined distance from the third steering start position to the avoidance end position are of different lengths. Thereby, the length of the steering section can be set according to the situations at the start and end of avoidance respectively.

[0081] Note that the target trajectory in the avoidance start steering section, the target trajectory in the approach section, and the target trajectory in the avoidance end steering section are each an example of the "first target trajectory", "second target trajectory", and "third target trajectory" described in the claims. The steering start position and the steering end position of the avoidance start steering section are each an example of the "first steering start position" and "first steering end position" described in the claims. The steering start position of the avoidance end steering section is an example of the "third steering start position" described in the claims.

[0082] Note that the embodiments described above are described to facilitate the understanding of the present invention and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

Explanation of Signs

[0083] 6…Travel control device 7…Processor 100…Host vehicle position estimation unit 101…Travel boundary acquisition unit 102…Surrounding information acquisition unit 103…Obstacle determination unit 104…Avoidance determination unit 105…Boundary setting unit 106... Orbit generation unit 107... Vehicle control unit

Claims

1. A driving control method executed by a processor, which sets left and right lane boundary lines of a road on which a vehicle is traveling as left and right lane boundary lines of a lane on which the vehicle is traveling, generates a target trajectory on a road center line between the lane boundary lines, and causes the vehicle to travel along the target trajectory, The processor, Acquire lane information around the vehicle; Acquire surrounding traffic condition information relating to traffic conditions around the vehicle; when an obstacle that obstructs travel of the host vehicle is detected in the host lane based on the lane information and the surrounding traffic condition information, determining whether or not to avoid the obstacle by avoidance control including steering control in an avoidance direction to avoid the obstacle; When it is determined that the obstacle is to be avoided, the lane boundary line on the avoidance direction side is extended from the lane boundary line on the avoidance direction side of the own lane to a boundary line on the avoidance direction side of an adjacent lane or a guidance strip adjacent to the own lane, a first target trajectory is generated as a trajectory for the host vehicle to travel by steering control between a first steering start position on a pre-expansion lane center line between the left and right lane boundary lines before expansion and a first steering end position on a post-expansion lane center line between the expanded lane boundary line on the avoidance direction side and the lane boundary line in the opposite direction to the avoidance direction; A driving control method in which the first steering end position is located on the side of the vehicle's direction of travel of the vehicle relative to the intersection of the track center line connecting the pre-expansion track center line and the post-expansion track center line and the post-expansion track center line.

2. The processor, The first steering end position is set at a position spaced a predetermined distance from the first steering start position in the traveling direction, 2. The driving control method according to claim 1, wherein the specified distance is longer as the expansion width, which is the difference between the length in the lane width direction between the expanded lane boundary line on the side of the avoidance direction and the lane boundary line in the direction opposite to the avoidance direction, and the length in the lane width direction between the left and right lane boundary lines before expansion, is larger.

3. The processor, The first steering end position is set at a position spaced a predetermined distance from the first steering start position in the traveling direction, The cruise control method according to claim 1 , wherein the predetermined distance is longer as the vehicle speed of the host vehicle increases.

4. The processor, When the host vehicle approaches the obstacle while traveling on the extended travel center line, the travel control method according to any one of claims 1 to 3, which generates a second target trajectory for the host vehicle to avoid the obstacle.

5. The processor sets the area including the obstacle as a non-travelable area, sets the road boundary line on the side opposite to the avoidance direction at the boundary line of the non-travelable area, The travel control method according to claim 4, wherein the second target trajectory is generated so that the host vehicle travels at a position separated from the road boundary line on the side opposite to the avoidance direction by a predetermined offset distance.

6. The processor When there is an approaching section where the distance between the extended travel center line and the boundary line of the non-travelable area is equal to or less than the predetermined offset distance, sets the target trajectory in the approaching section as the second target trajectory. The travel control method according to claim 5.

7. The processor executes first steering control so that the host vehicle travels along the first target trajectory, The travel control method according to any one of claims 4 to 6, which executes second steering control so that the host vehicle travels along the second target trajectory.

8. The processor sets an avoidance start position and an avoidance end position of an avoidance section for performing the avoidance control, sets the avoidance start position as the first steering start position, and sets the first steering end position at a position separated from the avoidance start position by the predetermined distance in the traveling direction, sets a third steering start position at a position separated from the avoidance end position by the predetermined distance in the direction opposite to the traveling direction, generates, as a third target trajectory, a trajectory for the host vehicle to travel by steering control between the third steering start position on the extended travel center line and the avoidance end position on the travel center line of the host lane, The travel control method according to claim 2 or 3, wherein the predetermined distance from the avoidance start position to the first steering end position and the predetermined distance from the third steering start position to the avoidance end position are different lengths.

9. A travel control device including a processor that sets the left and right road boundary lines of the road on which the host vehicle travels at the left and right lane boundary lines of the host lane in which the host vehicle travels, generates a target trajectory on the travel center line between the road boundary lines, and causes the host vehicle to travel along the target trajectory. The processor acquires lane information around the host vehicle, Acquire surrounding traffic condition information relating to traffic conditions around the vehicle; when an obstacle that obstructs travel of the host vehicle is detected in the host lane based on the lane information and the surrounding traffic condition information, determining whether or not to avoid the obstacle by avoidance control including steering control in an avoidance direction to avoid the obstacle; When it is determined that the obstacle is to be avoided, the lane boundary line on the avoidance direction side is extended from the lane boundary line on the avoidance direction side of the own lane to a boundary line on the avoidance direction side of an adjacent lane or a guidance strip adjacent to the own lane, a first target trajectory is generated as a trajectory for traveling by steering control between a first steering start position on a pre-expansion lane center line between the left and right lane boundary lines before expansion and a first steering end position on a post-expansion lane center line between the expanded lane boundary line on the avoidance direction side and the expanded lane boundary line in the opposite direction to the avoidance direction; A driving control device in which the first steering end position is located on the side of the vehicle's direction of travel of the vehicle relative to the intersection of the track center line connecting the pre-expansion track center line and the post-expansion track center line and the post-expansion track center line.

Images