Travel control device, travel control method, and non-transitory computer-readable medium storing a travel control computer program

Abstract

Provided are a driving control device, a driving control method, and a non-transitory computer-readable medium storing a driving control computer program. The driving control device creates multiple paths from a current lane in which a vehicle is currently traveling, through a laneless section without lane dividing lines, toward lanes other than the current lane among multiple lanes divided by lane dividing lines located ahead in the direction of travel. The device determines a path among the multiple paths that corresponds to the vehicle's forward course in the laneless section, calculated using output data from sensors mounted on the vehicle, as a driving path, and controls the vehicle's travel so as to maintain the lane among the multiple lanes toward which the driving path is directed.

Description

Technical Field

[0001] The present disclosure relates to a travel control device and a travel control method for automatically controlling the travel of a vehicle, and a non-transitory computer-readable medium storing a computer program for the travel control. Background Art

[0002] A driving control device that automatically controls vehicle travel based on surrounding images generated by a camera mounted on the vehicle detects lane dividing lines from the surrounding images and controls the vehicle's travel so that it stays in the lane defined by the lane dividing lines (lane keeping control). Alternatively, the driving control device controls the vehicle's travel so that it moves from its current lane to another lane on a road with multiple lanes (lane change control).

[0003] Japanese Patent Application Publication No. 2020-126024 (hereinafter referred to as "Patent Document 1") describes a vehicle control system that automatically changes lanes from the current lane to a branch lane having multiple lanes. When changing lanes from the current lane to a branch lane having multiple lanes, there may be a need to change lanes to another lane in the branch lane after changing lanes to one of the lanes. In the vehicle control system described in Patent Document 1, the method of generating a driving path is different when changing lanes to the lane farthest from the current lane among the lanes included in the branch lane and when changing lanes to another lane included in the branch lane, thereby reducing the number of lane changes.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-126024 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] When changing lanes from the current lane to the added lane at a location without lane demarcation lines, such as a lane addition point, the driving control system cannot appropriately determine whether movement to the target lane has completed based on the lane demarcation lines. Consequently, the driving control system may switch from lane change control to lane keeping control at a location corresponding to a lane different from the target lane, and control driving in the different lane.

[0009] An object of the present disclosure is to provide a travel control device capable of controlling vehicle travel so as to appropriately change the travel lane even at a location without lane dividing lines.

[0010] Means for solving problems

[0011] The driving control device disclosed in the present invention includes: a path creation unit that creates multiple paths from a current lane in which a vehicle is currently traveling through a lane-free section without lane dividing lines toward lanes other than the current lane among multiple lanes divided by lane dividing lines located ahead in the direction of travel; a path determination unit that determines, as a traveling path, a path among the multiple paths that corresponds to the forward route of the vehicle traveling in the lane-free section calculated using output data of sensors mounted on the vehicle; and a lane keeping control unit that controls the driving of the vehicle so as to maintain the lane to which the driving path is directed among the multiple lanes.

[0012] Preferably, the travel control device of the present disclosure further includes a lane change control unit that controls travel of the vehicle so as to move from the current lane to a target lane other than the current lane among the plurality of lanes.

[0013] Preferably, in the travel control device of the present disclosure, the route determination unit determines, as the traveling route, a route facing a direction corresponding to the traveling direction of the vehicle in the laneless section among the plurality of routes.

[0014] Preferably, in the travel control device of the present disclosure, when only one of the plurality of paths is a path that the vehicle can travel from a current position in the laneless section, the path determination unit determines the one path as the traveling path.

[0015] Preferably, in the travel control device of the present disclosure, the route determination unit determines the travel route after a distance from a current position of the vehicle from a current lane in the laneless section exceeds a distance threshold.

[0016] The driving control method disclosed herein includes: creating multiple paths from a current lane in which a vehicle is currently traveling, through a lane-free section without lane dividing lines, respectively, toward a lane other than the current lane among a plurality of lanes divided by lane dividing lines located ahead in the direction of travel; determining a path among the multiple paths that corresponds to the forward route of the vehicle traveling in the lane-free section calculated using output data of a sensor mounted in the vehicle as a traveling path; and controlling the driving of the vehicle so as to maintain the lane toward which the traveling path is directed among the multiple lanes.

[0017] The computer program for driving control stored in the non-temporary computer-readable medium of the present disclosure causes a processor to execute: generating multiple paths from a current lane in which a vehicle is currently traveling through a lane-free section without lane dividing lines toward lanes other than the current lane among multiple lanes divided by lane dividing lines located ahead in the direction of travel; determining a path among the multiple paths that corresponds to the forward route of the vehicle traveling in the lane-free section calculated using output data of sensors mounted in the vehicle as a traveling path; and controlling the driving of the vehicle so as to maintain the lane toward which the traveling path is directed among the multiple lanes.

[0018] The travel control device according to the present disclosure can control the travel of a vehicle so that the lane in which the vehicle travels can be appropriately changed even at a location where there are no lane dividing lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of a vehicle equipped with a travel control device.

[0020] Figure 2 This is a hardware diagram of the travel control device.

[0021] Figure 3 This is a functional block diagram of a processor included in the travel control device.

[0022] Figure 4 This is a diagram illustrating a first example of path determination.

[0023] Figure 5 This is a diagram illustrating a second example of path determination.

[0024] Figure 6 This is a flowchart of the travel control process.

[0025] (Explanation of Reference Numerals)

[0026] 1: Vehicle; 5: Driving control device; 531: Lane change control unit; 532: Path creation unit; 533: Path determination unit; 534: Lane keeping control unit. DETAILED DESCRIPTION

[0027] The following describes in detail a driving control device that can appropriately change a vehicle's lane even in locations without lane dividing lines, with reference to the accompanying drawings. The driving control device creates multiple paths that lead from the vehicle's current lane through a laneless section without lane dividing lines, each toward a lane other than the current lane, among multiple lanes divided by lane dividing lines located ahead in the direction of travel. Furthermore, the driving control device identifies, as the driving path, a path among the multiple paths that corresponds to the vehicle's forward path in the laneless section, calculated using output data from sensors mounted on the vehicle. The driving control device then controls the vehicle's driving to maintain the lane among the multiple lanes toward which the driving path is directed.

[0028] Figure 1 This is a schematic diagram of the structure of a vehicle equipped with a travel control device.

[0029] Vehicle 1 includes a camera 2, a GNSS (Global Navigation Satellite System) receiver 3, a storage device 4, and a travel control device 5. The camera 2, GNSS receiver 3, storage device 4, and travel control device 5 are communicatively connected via an in-vehicle network conforming to a standard such as a controller area network.

[0030] Camera 2 is an example of a sensor used to detect conditions near the vehicle. Camera 2 includes a two-dimensional detector composed of an array of photoelectric conversion elements sensitive to visible light, such as CCDs or C-MOSs, and an imaging optical system that forms an image of the area to be imaged on the two-dimensional detector. Camera 2 is positioned, for example, in the upper front portion of the vehicle interior, facing forward. It captures conditions around vehicle 1 through the front windshield at a predetermined interval (e.g., 1 / 30 to 1 / 10 second) and outputs an image corresponding to the surrounding conditions. An image is an example of sensor output data.

[0031] The GNSS receiver 3 receives GNSS signals from GNSS (Global Navigation Satellite System) satellites at a predetermined interval and determines the vehicle 1's own position based on the received GNSS signals. The GNSS receiver 3 outputs a positioning signal indicating the positioning result of the vehicle 1's own position based on the GNSS signals to the driving control device 5 at a predetermined interval via the in-vehicle network.

[0032] The storage device 4 is an example of a storage unit and includes, for example, a hard disk drive or a nonvolatile semiconductor memory. The storage device 4 stores a high-precision map. The high-precision map includes, for example, information indicating lane-free sections and lane markings for each road within a predetermined area represented on the high-precision map.

[0033] The driving control device 5 is an ECU (Electronic Control Unit) equipped with a communication interface, memory, and a processor. Based on images received from the camera 2 via the communication interface, the driving control device 5 detects lane markings and lanes ahead of the vehicle 1 and controls the vehicle 1 to stay within the specified lane.

[0034] Figure 2 2 is a hardware diagram of the travel control device 5. The travel control device 5 includes a communication interface 51, a memory 52, and a processor 53.

[0035] The communication interface 51 is an example of a communication unit and includes a communication interface circuit for connecting the travel control device 5 to the in-vehicle network. The communication interface 51 supplies received data to the processor 53. The communication interface 51 also outputs data supplied from the processor 53 to the outside.

[0036] The memory 52 is an example of a storage unit and includes volatile semiconductor memory and nonvolatile semiconductor memory. The memory 52 stores various data used in processing by the processor 53, such as a distance threshold that determines the distance of the vehicle 1 from the current lane at which lane keeping control can be initiated. The memory 52 also stores various application programs, such as a driving control program that executes driving control processing.

[0037] The processor 53 is an example of a control unit and includes one or more processors and their peripheral circuits. The processor 53 may also include other arithmetic circuits such as a logical operation unit, a numerical operation unit, or a graphics processing unit.

[0038] Figure 3 This is a functional block diagram of the processor 53 included in the travel control device 5 .

[0039] The processor 53 of the driving control device 5 includes, as functional blocks, a lane change control unit 531, a route creation unit 532, a route determination unit 533, and a lane keeping control unit 534. These components of the processor 53 are functional modules implemented by programs executed on the processor 53. Alternatively, these components of the processor 53 may be implemented in the driving control device 5 as independent integrated circuits, microprocessors, or firmware.

[0040] The lane change control unit 531 controls the driving of the vehicle 1 so that the vehicle 1 moves from the current lane in which it is currently traveling, through a lane-free section without lane dividing lines, to a target lane other than the current lane among multiple lanes divided by lane dividing lines located ahead in the direction of travel.

[0041] The lane change control unit 531 inputs the image received from the camera 2 via the communication interface into a recognizer that has been previously trained to detect lane dividing lines displayed on the road to distinguish lanes, thereby determining the lane-free section and lane dividing lines in front of the vehicle 1.

[0042] The recognizer can be, for example, a convolutional neural network (CNN) having multiple convolutional layers connected in series from the input side to the output side. Images containing lane markings are pre-trained and fed into the CNN for learning, so that the CNN functions as a recognizer that detects lane markings from images.

[0043] The lane change control unit 531 may also obtain from the storage device 4 information on lane-free sections and lane dividing lines that exist in the high-precision map around the current position of the vehicle 1 represented by the positioning signal received from the GNSS receiver 3 via the communication interface.

[0044] In addition, the lane change control unit 531 can also obtain from the storage device 4 information on lane-free sections and lane dividing lines that exist in the high-precision map around the current position of the vehicle 1 determined by the vehicle's driving history using a wheel speed sensor (not shown) and a gyro sensor (not shown).

[0045] The lane change control unit 531 outputs a control signal to the driving mechanism (not shown) of the vehicle 1 via the communication interface 51 to cause the vehicle 1 to move from its current lane to its target lane. The driving mechanism includes, for example, an engine or motor that powers the vehicle 1, brakes that reduce the speed of the vehicle 1, and a steering mechanism that steers the vehicle 1.

[0046] The target lane is selected from multiple lanes based on the driving plan from the current location to the destination. For example, if the vehicle plans to change course toward a branch road ahead of the current location, the lane that can be entered into the branch road is selected as the target lane.

[0047] The route creation unit 532 creates multiple routes that lead from the current lane through a lane-free zone to multiple lanes, including a target lane, located ahead in the direction of travel. The route creation unit 532 creates the multiple routes by connecting a lane change start position in the current lane, where a lane change begins, with lane change end positions in each of multiple lanes ahead of the lane change start position, where lane changes end. The lane change start position and the lane change end position include a lane-free zone.

[0048] The path determination unit 533 uses data output from the camera 2 mounted on vehicle 1 to identify, as the current path, the path corresponding to the vehicle 1's route through the lane-free section from among multiple paths. The path determination unit 533 inputs images received from the camera 2 via the communication interface into a recognition unit pre-trained to detect lane dividing lines, which are lines displayed on the road to distinguish lanes. This identifies the lane dividing lines surrounding vehicle 1. Based on the positions of the identified lane dividing lines, the path determination unit 533 then detects a path indicating the direction of vehicle 1's travel in the lane-free section.

[0049] Figure 4 This is a diagram illustrating a first example of path determination.

[0050] Before starting a lane change, vehicle 1 is traveling in current lane L11, which is divided by lane dividing lines LL11 and LL12. Lane L12, which is divided by lane dividing lines LL13 and LL14, and lane L13, which is divided by lane dividing lines LL14 and LL12, are located ahead of vehicle 1 in the direction of travel, across a laneless zone NLZ1 without lane dividing lines. Furthermore, in front of vehicle 1, current lane L11 is divided by lane dividing lines LL11 and LL13.

[0051] exist Figure 4 In the example, lane L13 is selected as the target lane. The lane change control unit 531 controls the vehicle 1 from the lane change start position LCS1 toward the lane change end position LCE1 so as to move from the current lane L11 to the target lane L13.

[0052] Path creation unit 532 creates paths R12 and R13 by connecting lane change start position LCS1 in current lane L11 with lane change end position LCE1 in lanes L12 and L13 other than current lane L11. Path creation unit 532 sets lane change end position LCE1 to a position where lane dividing line LL14, which is not present at lane change start position LCS1, exists.

[0053] Path R12 is a path toward a direction forming an angle α from the traveling direction D11 of the vehicle 1 at the lane change start position LCS1 Path R13 is a path toward a direction forming an angle β from the traveling direction D11 of the vehicle 1 at the lane change start position LCS1 .

[0054] After passing lane change start position LCS1, vehicle 1 is controlled by lane change control unit 531 to move from current lane L11 toward lane L13, and is now traveling at a distance I from current lane L11. At this point, vehicle 1's traveling direction is D12. Traveling direction D12 is the direction that forms an angle γ with vehicle 1's traveling direction D11 at lane change start position LCS1.

[0055] After the distance I of the current position of the vehicle 1 in the laneless zone NLZ1 from the current lane L11 exceeds the distance threshold stored in the memory 52, the path determination unit 533 determines the path corresponding to the travel direction D12 at the current position of the vehicle 1 among the paths R12 and R13 as the traveling path.

[0056] The path determination unit 533 calculates the difference between the angles formed by direction D11 and the directions of paths R12 and R13, and the angle formed by direction D11 and the direction D12 of vehicle 1's current position. Path R13, which has the smallest difference, is determined as the traveling path. Alternatively, the path determination unit 533 may determine the path with the smallest difference as the traveling path, among paths whose differences are smaller than a threshold value of angle difference pre-stored in memory 52. ​​Alternatively, instead of calculating the difference between the angle formed by direction D11 and the directions of paths R12 and R13 and the angle formed by direction D11 and the direction D12 of vehicle 1's current position, the path determination unit 533 may determine the traveling path using the ratio of the angle formed by direction D11 and the directions of paths R12 and R13 to the angle formed by direction D11 and the direction D12 of vehicle 1's current position.

[0057] Figure 5 This is a diagram illustrating a second example of path determination.

[0058] Before starting a lane change, vehicle 1 is traveling in current lane L21, which is divided by lane dividing lines LL21 and LL22. Lane L22, which is divided by lane dividing lines LL23 and LL24, and lane L23, which is divided by lane dividing lines LL24 and LL22, are located ahead of vehicle 1 in the direction of travel, separated by a laneless zone NLZ2 without lane dividing lines. Furthermore, in front of vehicle 1, current lane L21 is divided by lane dividing lines LL21 and LL23.

[0059] exist Figure 5 In the example, lane L22 is selected as the target lane. The lane change control unit 531 controls the vehicle 1 from the lane change start position LCS2 toward the lane change end position LCE2 so as to move from the current lane L21 to the lane L22 as the target lane.

[0060] Path creation unit 532 creates paths R22 and R23 by connecting lane change start position LCS2 in the current lane L21 with lane change end position LCE2 in lanes L22 and L23. Path creation unit 532 sets lane change end position LCE2 to a position where lane dividing line LL24, which is not present at lane change start position LCS2, exists.

[0061] After passing the lane change start position LCS2, the vehicle 1 first travels from the current lane L21 toward the lane L22 based on the travel control performed by the lane change control unit 531. Figure 5 In the example of FIG. 2 , the vehicle 1 travels in the traveling direction D20 by the additional steering performed by the driver of the vehicle 1 after passing the lane change start position LCS2 .

[0062] The route determination unit 533 determines whether routes R22 and R23 are traversable from the current position of vehicle 1. To travel from the current position of vehicle 1 toward routes R22 and R23, respectively, vehicle 1 must travel in directions D22 and D23 connecting the current position and the endpoints of routes R22 and R23. The route determination unit 533 calculates the angle formed between vehicle 1's travel direction D20 and directions D22 and D23, respectively. The route determination unit 533 defines the direction of direction D22 or D23 whose angle with travel direction D20 is less than the maximum steering angle determined based on the current speed of vehicle 1 as the traversable direction from the current position and determines the route corresponding to that direction as the traversable route from the current position. If only one of the multiple routes is traversable from the current position, the route determination unit 533 determines that route as the traversable route.

[0063] exist Figure 5 In the example shown in FIG, direction D22 is not a travelable direction from the current position, but direction D23 is a travelable direction from the current position. Therefore, the route determination unit 533 determines the route R23 corresponding to direction D23 as the traveling route.

[0064] The lane keeping control unit 534 controls the travel of the vehicle 1 so as to maintain the lane toward which the vehicle is traveling among a plurality of lanes divided by lane dividing lines.

[0065] The lane keeping control unit 534 determines a lane dividing line that divides the lane in the direction of the traveling route, and outputs a control signal to a travel mechanism (not shown) of the vehicle 1 via the communication interface 51 so as to maintain the lane divided by the lane dividing line.

[0066] Determination of the lane dividing line and output of the control signal to the driving mechanism are the same as those of the lane change control unit 531 , and therefore detailed description thereof will be omitted.

[0067] Figure 6 Flowchart of the driving control process. After the vehicle 1 starts lane change control and the distance from the current lane to the current position of the vehicle 1 exceeds the distance threshold stored in the memory 52, the driving control device 5 executes the following steps: Figure 6 The processing shown.

[0068] First, the route creation unit 532 creates a plurality of routes from the current lane in which the vehicle 1 is currently traveling among a plurality of lanes divided by lane dividing lines toward lanes other than the current lane among the plurality of lanes (step S1 ).

[0069] Next, the route identification unit 533 identifies a traveling route corresponding to the route along which the vehicle 1 is traveling, among the plurality of routes (step S2 ).

[0070] Then, the lane keeping control unit 534 controls the travel of the vehicle 1 so as to maintain the lane toward which the vehicle is traveling among the plurality of lanes (step S3 ).

[0071] By executing the travel control process in this manner, the travel control device 5 can control the travel of the vehicle 1 so as to appropriately change the travel lane even at a location where there are no lane dividing lines.

[0072] It should be understood that those skilled in the art can add various changes, substitutions, and modifications without departing from the spirit and scope of the present disclosure.

Claims

1. A driving control device comprising: a path generating unit configured to generate a plurality of paths, each of which is a plurality of paths leading from a current lane in which the vehicle is currently traveling, through a laneless section having no lane dividing lines, to a lane other than the current lane among a plurality of lanes divided by the lane dividing lines located ahead in the direction of travel; a path determination unit that, after a distance of the current position of the vehicle in the laneless section from the current lane exceeds a distance threshold, determines, as a traveling path, a path among the plurality of paths that corresponds to a course of travel of the vehicle in the laneless section calculated using output data of a sensor mounted on the vehicle; as well as The lane keeping control unit controls the travel of the vehicle so as to maintain the lane to which the traveling path is directed among the plurality of lanes.

2. The travel control device according to claim 1, further comprising: The lane change control unit controls the travel of the vehicle so as to move from the current lane to a target lane other than the current lane among the plurality of lanes.

3. The travel control device according to claim 1 or 2, wherein: The path determination unit determines, as the traveling path, a path among the plurality of paths, the direction of which corresponds to the traveling direction of the vehicle traveling in the laneless section.

4. The travel control device according to claim 1 or 2, wherein: When only one of the plurality of routes is a route that the vehicle can travel from the current position in the laneless section, the route determination unit determines the one route as the traveling route.

5. A driving control method comprising: creating a plurality of paths, each of which is a plurality of paths that leads from a current lane in which the vehicle is currently traveling, through a laneless section without lane dividing lines, toward a lane other than the current lane among a plurality of lanes divided by the lane dividing lines located ahead in the direction of travel; After a distance of the current position of the vehicle in the lane-free section from the current lane exceeds a distance threshold, determining a path among the plurality of paths corresponding to a forward route of the vehicle traveling in the lane-free section calculated using output data of a sensor mounted on the vehicle as a traveling path; as well as Travel of the vehicle is controlled so as to maintain the lane toward which the traveling path is directed among the plurality of lanes.

6. A non-transitory computer-readable medium storing a computer program, the computer program causing a processor to execute: creating a plurality of paths, each of which is a plurality of paths that leads from a current lane in which the vehicle is currently traveling, through a laneless section without lane dividing lines, toward a lane other than the current lane among a plurality of lanes divided by the lane dividing lines located ahead in the direction of travel; After a distance of the current position of the vehicle in the lane-free section from the current lane exceeds a distance threshold, determining a path among the plurality of paths corresponding to a forward route of the vehicle traveling in the lane-free section calculated using output data of a sensor mounted on the vehicle as a traveling path; as well as Travel of the vehicle is controlled so as to maintain the lane toward which the traveling path is directed among the plurality of lanes.

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