Vehicle control method and vehicle control device

Abstract

A vehicle control device (10) controls a lane change of an own vehicle (1). When the vehicle control device (10) determines that a lane change of the own vehicle (1) is required, the vehicle control device (10) derives, on the basis of signal information or traffic information acquired by a communication module (230) or an external sensor (240), a non-recommended area in which it is estimated that an inter-vehicle distance to another vehicle traveling in an adjacent lane that is the lane change destination will decrease. The vehicle control device (10) performs control to cause the own vehicle (1) to execute a lane change in a recommended area set outside the non-recommended area.

Description

Vehicle control method and vehicle control device

[0001] The present invention relates to a vehicle control method and a vehicle control device.

[0002] In the automatic driving control or driving support control of a vehicle, there is a technology for controlling a lane change to an adjacent lane required according to the situation of the lane in which the vehicle is traveling or the destination of the vehicle (for example, Patent Document 1). Patent Document 1 describes a driving support device that controls a lane change when there is an obstacle to passage ahead in the current lane in which the host vehicle is traveling. The driving support device described in Patent Document 1 determines whether or not the host vehicle can return to the current lane up to a predetermined position based on the intersection after changing lanes to an adjacent lane according to the distance from the obstacle to the intersection or the road conditions, and notifies the result. Thereby, it is explained that it is possible to determine the feasibility of a lane change on the premise of returning to the current lane.

[0003] Japanese Patent Application Laid-Open No. 2019-74431

[0004] According to the driving support device of Patent Document 1, when there is no obstacle in the adjacent lane and there is no problem on the route, a notification recommending a lane change to the adjacent lane is given, but a situation where a lane change is difficult may occur at a timing when the inter-vehicle distance between vehicles in the adjacent lane is reduced, such as when the traffic signal ahead turns red.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a vehicle control method and a vehicle control device capable of performing smooth vehicle control for lane changes.

[0006] To achieve the above object, a vehicle control method according to the present invention is a vehicle control method for controlling a lane change of a host vehicle. When it is determined that a lane change of the host vehicle is required, based on signal information related to a signal in front of the host vehicle or traffic information related to the road on which the host vehicle is traveling, a non-recommended area where it is estimated that the inter-vehicle distance of other vehicles traveling in the adjacent lane to the lane change destination will decrease is derived, and the lane change is carried out in a recommended area for lane change set outside the non-recommended area.

[0007] According to the present invention, lane changes are performed in recommended areas, which are set outside of non-recommended areas where it is estimated that the distance between vehicles in adjacent lanes will decrease, thereby enabling smooth vehicle control during lane changes.

[0008] This is a block diagram showing an example of the functional configuration of a vehicle control device according to Embodiment 1 of the present invention. This is a diagram showing an example of the hardware configuration of the controller of the vehicle control device according to Embodiment 1. This is a diagram showing an example of a recommended area for lane changes according to Embodiment 1. This is a diagram showing examples of recommended and non-recommended areas for lane changes according to Embodiment 1. This is a diagram showing the difference in vehicle speed changes due to traffic volume. This is a diagram showing the difference in vehicle speed changes due to average vehicle speed. This is a flowchart of the vehicle control process according to Embodiment 1. This is a flowchart of the vehicle control process according to Embodiment 2. This is a diagram showing examples of recommended and non-recommended areas for lane changes according to Embodiment 2. This is a flowchart of a part of the vehicle control process according to a modified example. This is a flowchart of the vehicle control process according to another modified example.

[0009] A vehicle control method and a vehicle control device according to embodiments of the present invention will be described with reference to the drawings. In each drawing, the same or equivalent parts are denoted by the same reference numerals.

[0010] (Embodiment 1) The vehicle control device 10 according to Embodiment 1 of the present invention is a device mounted on a vehicle that controls the vehicle's movement. The vehicle control device 10 enables driver assistance or autonomous driving of the vehicle by controlling actuators that drive various parts of the vehicle. For example, in a vehicle with a driver assistance function, the vehicle control device 10 performs control to execute a lane change when the driver performs a lane change operation, or when it determines that a lane change is necessary and proposes a lane change, and the driver approves the operation. Alternatively, for example, in a vehicle performing Level 4 autonomous driving, the vehicle control device 10 performs control to execute a lane change when it determines that a lane change is necessary.

[0011] Figure 1 is a diagram showing an example of the functional configuration of the vehicle control device 10 according to this embodiment, and represents the parts related to vehicle control according to this embodiment. The vehicle equipped with the vehicle control device 10 and performing lane changes is called the vehicle itself 1. When the vehicle control device 10 determines that a lane change is necessary, it controls the lane change of the vehicle itself 1 by accelerating, decelerating, steering, etc., according to the situation of other vehicles traveling in adjacent lanes. The vehicle control device 10 may also perform control such as lane keeping control, preceding vehicle following control, and collision avoidance control in parallel with other control units (not shown).

[0012] As shown in Figure 1, the vehicle control device 10 includes a location information acquisition unit 210 that acquires location information of the vehicle 1, a map database 220 that stores map information including the roads on which the vehicle 1 travels, a communication module 230 that communicates wirelessly with the outside, an external sensor 240 that detects objects around the vehicle 1, and a controller 100 that performs lane change control based on the information acquired by the communication module 230 or the external sensor 240.

[0013] The position information acquisition unit 210 is any device capable of acquiring the position of the vehicle 1, such as a GNSS (Global Navigation Satellite System) receiver. The GNSS receiver receives orbital information and time information from multiple positioning satellites and outputs position information indicating the position of the vehicle 1 calculated based on the received signals to the controller 100.

[0014] The map database 220 is a database that stores map information including road information, intersection information, facility information, etc., for the area in which the vehicle 1 travels. In this embodiment, the map information contained in the map database 220 may also include information necessary for vehicle control, including lane changes, such as lane restrictions, traffic light information, the number of lanes, and speed limits.

[0015] The communication module 230 includes a wireless communication module that performs wireless communication using any standard, such as mobile phone communication or wireless LAN (Local Area Network). The communication module 230 connects to a server that manages traffic information or signal information via any network and transmits and receives data. The communication module 230 also connects to roadside devices such as infrastructure cameras and traffic lights directly or via any network and transmits and receives data. Infrastructure cameras are installed on the side of the road or above the road and monitor traffic conditions such as lane closures, congestion, accidents, malfunctions, fallen objects, construction, and traffic volume. Traffic lights hold signal information such as signal status and the timing of signal changes. The communication module 230 can receive publicly available information from the information held by the server or roadside devices.

[0016] The external sensor 240 is any sensor that detects objects, including roads and other vehicles, that exist around the vehicle 1. Examples of external sensors 240 include cameras, LiDAR (Light Detection and Ranging), RADAR (Radio Detection and Ranging), LRF (Laser Range-Finder), SONAR (Sound Navigation and Ranging), etc. Based on the output of the external sensor 240 installed on the front of the vehicle 1, the controller 100 can detect signals or detect preceding vehicles or obstacles. In addition, based on the output of the external sensor 240 installed on the side of the vehicle 1, the controller 100 can measure the presence of other vehicles to the side of the vehicle 1, the distance between vehicles, vehicle speed, etc.

[0017] Figure 2 shows an example of the hardware configuration of the controller 100 of the vehicle control device 10. In the example in Figure 2, the controller 100 comprises a processor 1011, a storage device 1012, and a communication interface 1013, all connected to each other via a bus 1010.

[0018] The processor 1011 comprises, for example, one or more CPUs (Central Processing Units) and their peripheral circuits, and performs various arithmetic operations. The processor 1011 executes programs for various arithmetic operations, including vehicle control operations, stored in the storage device 1012. The processor 1011 may also include volatile semiconductor memory such as RAM (Random Access Memory) that functions as the CPU's working memory. Furthermore, the processor 1011 may also include arithmetic circuits such as a logical operation unit and a numerical operation unit.

[0019] The storage device 1012 includes, for example, a non-volatile semiconductor memory such as EEPROM (Electrically Erasable and Programmable Read Only Memory) or flash memory. The storage device 1012 stores programs for various arithmetic processes, including vehicle control processing, executed by the processor 1011, and various data used in the arithmetic processing of the processor 1011.

[0020] The communication interface 1013 includes an interface circuit for connecting the processor 1011 to an in-vehicle network compliant with standards such as CAN (Controller Area Network). The communication interface 1013 receives signals from the location information acquisition unit 210, map database 220, communication module 230, and external sensor 240, as well as from other in-vehicle components such as vehicle sensors and user interfaces, and passes them to the processor 1011.

[0021] Furthermore, the communication interface 1013 is connected to various actuators 250 that operate the vehicle, and transmits control signals generated by the processor 1011 to each actuator 250 to control the vehicle. The actuators 250 include, for example, an accelerator actuator (at least one of the engine and motor) for accelerating the vehicle, a brake actuator for braking the vehicle, and a steering actuator for steering the vehicle. In this way, the vehicle control device 10 realizes driver assistance or autonomous driving of the vehicle by controlling each actuator 250.

[0022] For example, the processor 1011 of the vehicle control device 10 executes a vehicle control processing program to realize each of the functions shown in Figure 1. That is, the vehicle control device 10 functions as a vehicle position estimation unit 101 that estimates the current position of the vehicle 1, a map information acquisition unit 102 that acquires map information for a range including the current position of the vehicle 1, and a lane change necessity determination unit 103 that determines whether or not a lane change is necessary.

[0023] Furthermore, the vehicle control device 10 functions as a recommended area setting unit 104 that sets a recommended area for lane changes to adjacent lanes, a lane change execution determination unit 105 that determines whether or not to perform a lane change in the recommended area, and a vehicle control unit 106 that controls the vehicle to perform the lane change that has been determined to be performed. Each of the functions of the vehicle control device 10 will be explained with reference to Figure 1.

[0024] The vehicle position estimation unit 101 estimates the position of the vehicle 1 on the map database 220 based on the output signal of the position information acquisition unit 210 installed in the vehicle 1. Here, the estimated vehicle position also estimates which lane the vehicle is traveling in out of the multiple lanes on one side of the road. The map information acquisition unit 102 acquires map information from the map database 220, including traffic light information, the number of lanes, speed limits, etc., within a predetermined range that includes the position of the vehicle 1 estimated by the vehicle position estimation unit 101. The map information acquisition unit 102 may further acquire route information from the car navigation system.

[0025] The lane change necessity determination unit 103 determines whether a lane change is necessary based on information acquired by the map information acquisition unit 102 or information received by the communication module 230. For example, when an infrastructure camera detects an event that obstructs traffic, such as lane blockage, congestion, accident vehicle, broken-down vehicle, fallen object, or construction, in front of the vehicle 1 traveling in its own lane, the communication module 230 receives traffic information including the event from the infrastructure camera, and the lane change necessity determination unit 103 determines, based on the traffic information received by the communication module 230, that a lane change to an adjacent lane is necessary. Alternatively, based on route information from the car navigation system acquired by the map information acquisition unit 102, the unit determines that a lane change to an adjacent lane is necessary if a lane change is required to turn right or left at an intersection in front of the vehicle 1.

[0026] The recommended area setting unit 104 sets a recommended area suitable for changing lanes to an adjacent lane when the lane change necessity determination unit 103 determines that a lane change is necessary. In this embodiment, the recommended area is set based on signal information received by the communication module 230 from a server or roadside unit, or detected by the external sensor 240. Here, the signal information used to set the recommended area may include information on the status of the signal and the timing of signal changes, as well as, for example, information obtained by observing traffic flow with an infrastructure camera and predicting the signal cycle. The setting of the recommended area will be explained using Figures 3 and 4. In the following explanation, signals that permit proceeding beyond the stop position, such as blue lights and blue arrow lights, will be called proceed signals, and signals that prohibit proceeding beyond the stop position, such as red lights and yellow lights, will be called stop signals.

[0027] As shown in Figure 3, based on the signal information, if it is determined that the signal 31 at the next intersection, which is the intersection immediately ahead of the vehicle 1, is a green light or other proceed signal and that the proceed signal will continue for a predetermined 1 hour or longer, then it is expected that there will be sufficient space in the adjacent lane 502 to which the vehicle will change lanes. Therefore, the recommended area setting unit 104 sets the area from the current position of the vehicle 1 to the intersection as the recommended area 21. The recommended area 21 is an area suitable for changing lanes from the vehicle 1's current lane 501 to the adjacent lane 502.

[0028] On the other hand, as shown in Figure 4, if the traffic light 31 at the next intersection is a stop signal such as a red light, or if it changes to a stop signal during the first hour, it is estimated that the distance between multiple other vehicles 2 in the adjacent lane 502 to which the lane change will occur will decrease due to the signal stop. In this area where the distance between vehicles decreases, the lane change is not suitable. Therefore, the recommended area setting unit 104 derives the area where the distance between vehicles is estimated to decrease as the non-recommended area 22.

[0029] More specifically, the unrecommended area 22 may be the area from the point where the following distance between multiple other vehicles 2 traveling in the adjacent lane 502 to the next lane begins to decrease until the next intersection. Alternatively, the unrecommended area 22 may be the area where the following distance between other vehicles 2 traveling in the adjacent lane 502 to the next lane is shorter than a predetermined threshold, or shorter than the average following distance on the road while traveling, as previously acquired by the external sensor 240 or infrastructure camera. The recommended area setting unit 104 sets recommended areas in addition to the derived unrecommended area 22. Specifically, the recommended area setting unit 104 sets the area before the derived unrecommended area 22 and the area after the intersection as recommended areas 23 and 24, respectively.

[0030] The length d of the vehicle 1 in the direction of travel within the non-recommended area 22 is derived by the communication module 230 according to the traffic conditions acquired from a server or roadside equipment such as an infrastructure camera. Figure 5 shows the difference in vehicle speed changes due to traffic volume, and Figure 6 shows the difference in vehicle speed changes due to average vehicle speed.

[0031] For example, if the traffic volume, which is the number of vehicles passing through the intersection per unit time, can be measured using an infrastructure camera, the length d is derived according to the traffic volume. As shown in Figure 5, when the traffic volume is high, the deceleration of vehicles due to the stop signal continues smoothly for a long time, so it is necessary to set the length d to be long. Therefore, the recommended area setting unit 104 may derive a longer value for the length d in the direction of travel of the non-recommended area 22 as the traffic volume increases.

[0032] Furthermore, if the average speed of vehicles passing through the intersection can be measured by the infrastructure camera, the length d is derived according to the average speed. As shown in Figure 6, a higher average speed means that deceleration begins earlier, so it is necessary to set the length d to be longer. Therefore, the recommended area setting unit 104 may derive a value that is longer as the average speed increases for the length d in the direction of travel of the non-recommended area 22.

[0033] Furthermore, if the communication module 230 can acquire signal information from a server or traffic light, and the signal at the next intersection is a stop signal, the recommended area setting unit 104 may derive a longer value for the length d of the non-recommended area 22 in the direction of travel as the elapsed time since the stop signal was issued increases. Alternatively, if the infrastructure camera can measure the number of vehicles stopped per unit time when the signal at the next intersection is a stop signal, the recommended area setting unit 104 may derive a longer value for the length d of the non-recommended area 22 in the direction of travel as the number of vehicles stopped per unit time increases. This makes it possible to derive a non-recommended area 22 that is more in line with the actual distance between vehicles.

[0034] Furthermore, the length d may be derived based on a combination of two or more of the above-mentioned conditions: traffic volume, average vehicle speed, elapsed time since the stop signal was issued, and the number of vehicles stopped per unit time at the stop signal. Alternatively, the length d may be derived based on other conditions or combinations of other conditions. Alternatively, the length d may be a predetermined fixed value.

[0035] When the traffic light 31 at the next intersection is showing a stop signal such as a red light, the recommended area setting unit 104 identifies an area of ​​length d before the intersection as a non-recommended area 22. However, when the traffic light 31 subsequently changes to a proceed signal such as a green light, the non-recommended area 22 is deactivated and changed to a recommended area 21. This deactivated non-recommended area 22 is unsuitable for lane changes because, at the time the traffic light 31 changes to a proceed signal, the distance between vehicles 2 in the adjacent lane 502 is still short. Therefore, it is necessary to pre-set the deactivation time, which is the time from when the signal changes to a proceed signal until the non-recommended area 22 is deactivated, as the second time. The deactivation time may be set to be longer the longer the distance from the intersection to the position of the stopped vehicle 1.

[0036] The recommended area setting unit 104 sets the area before the non-recommended area 22 and the area beyond the intersection, which were derived in this way, as recommended areas 23 and 24, respectively. The lane change execution determination unit 105 determines whether or not to perform a lane change in the recommended areas 21, 23, and 24 set by the recommended area setting unit 104.

[0037] More specifically, the lane change execution determination unit 105 determines whether a lane change can be completed within the recommended areas 21 and 23 set by the recommended area setting unit 104. If the lane change can be completed within the recommended areas 21 and 23 and the vehicle 1 can begin driving straight in the adjacent lane 502 to which the lane change will be made, the unit determines to perform the lane change. If it is predicted that the lane change cannot be completed within the recommended areas 21 and 23, the unit determines not to perform the lane change within those recommended areas 21 and 23 and to perform the lane change in the next recommended area 24 or later.

[0038] When the lane change execution determination unit 105 determines that a lane change should be performed, the vehicle control unit 106 controls each actuator 250 to change the vehicle 1 from its own lane 501 to the adjacent lane 502. More specifically, based on the output of the external sensor 240, the vehicle control unit 106 sets a target trajectory and target vehicle speed to enter the open space between other vehicles 2 traveling in the adjacent lane 502, and controls the accelerator actuator, brake actuator, and steering actuator so that the vehicle 1 travels along these.

[0039] The operation of the vehicle control device 10 configured as described above will be explained in detail with reference to Figure 7. Figure 7 is an example of a flowchart of the vehicle control processing performed by the vehicle control device 10 of the vehicle 1. The processing shown in the flowchart of Figure 7 is performed in parallel with other vehicle control processing such as lane keeping control processing and collision avoidance processing, for example, at predetermined time intervals.

[0040] First, the vehicle position estimation unit 101 estimates the position of the vehicle 1 on the map in the map database 220 (vehicle position) based on the output signal of the position information acquisition unit 210, and the map information acquisition unit 102 acquires map information within a predetermined range including the estimated position of the vehicle 1 from the map database 220. Based on the acquired map information or the information received by the communication module 230, the lane change necessity determination unit 103 determines whether or not a lane change is necessary (step S101).

[0041] For example, when the communication module 230 receives traffic information from the infrastructure camera regarding lane closure, congestion, accidents, breakdowns, fallen objects, construction, etc., in the vehicle's own lane 501, the lane change necessity determination unit 103 determines that a lane change to the adjacent lane 502 is required. Alternatively, the lane change necessity determination unit 103 determines, based on the route information of the car navigation system, whether a lane change is required to turn right or left at the intersection ahead of the vehicle 1. If it is determined that a lane change is not required (step S101: No), the process ends.

[0042] If it is determined that a lane change is necessary (Step S101: Yes), the recommended area setting unit 104 acquires signal information, including the status of the traffic lights at the next intersection, which is the intersection immediately ahead of the vehicle 1 (Step S102). It determines whether the signal information acquired in Step S102 is a green light or other proceed signal, and whether the proceed signal will continue for a predetermined period of 1 hour or more (Step S103).

[0043] When it is determined that the green signal continues for more than the first time based on the signal information (step S103: Yes), the recommended area setting unit 104 determines whether sufficient time has elapsed since the signal changed to the green signal. More specifically, the recommended area setting unit 104 determines whether a predetermined second time has elapsed since the signal changed to the green signal (step S104).

[0044] If the second time has not elapsed (step S104: No), since it is predicted that the reduction in the inter-vehicle distance due to the stop signal continues, the process ends without performing a lane change. In this case, a lane change may be executed at the timing when the second time has elapsed. The first time and the second time used in steps S103 and S104 are arbitrary times determined in advance, for example, 10 seconds. The first time and the second time may be the same as each other, or may be different from each other. At least one of the first time and the second time may be set longer as the distance of the host vehicle 1 from the intersection is longer.

[0045] If the second time has elapsed after the signal changes to the green signal (step S104: Yes), it is predicted that the reduction in the inter-vehicle distance between other vehicles 2 has been eliminated in the adjacent lane 502 of the lane change destination of the host vehicle 1. Therefore, the recommended area setting unit 104 sets the area from the point where the host vehicle 1 is located to the intersection as the recommended area 21 (step S105) and proceeds to step S108. That is, the second time can be rephrased as the release time until the area set as the non-recommended area 22 in the past process is released due to the change to the green signal.

[0046] If the signal information acquired in step S102 is a stop signal such as a red signal, or indicates that the time for which a green signal or the like continues is shorter than the first time (step S103: No), it is predicted that the inter-vehicle distance will decrease in front of the intersection. Therefore, the recommended area setting unit 104 derives an area where the distance from the intersection is less than or equal to the length d as a non-recommended area 22 that is not suitable for a lane change due to the reduction in the inter-vehicle distance in the lane change destination (step S106).

[0047] Here, as the length d of the non-recommended area 22 in the traveling direction, a longer value may be derived as the traffic volume at the intersection is larger. Also, as the length d, a longer value may be derived as the average vehicle speed of the vehicles passing through the intersection is higher. Further, as the length d, a longer value may be derived as the elapsed time since the stop signal is longer. Additionally, as the length d, a longer value may be derived as the number of vehicles stopping before the intersection is larger.

[0048] The recommended area setting unit 104 sets a recommended area outside the non-recommended area 22 derived in step S106. Specifically, the recommended area setting unit 104 sets, for the next intersection, the area in front of the non-recommended area 22 derived in step S106 as the recommended area 23, and sets the area after the intersection as the recommended area 24 (step S107). Here, based on the output of the external sensor 240 or the map information, sections within the intersection that are determined to be unsuitable for lane change or where lane change is prohibited, such as sections where the lane markings are yellow, are not included in the recommended areas 23 and 24.

[0049] Next, when the lane change execution determination unit 105 determines that the host vehicle 1 is traveling in the recommended areas 21 and 23 set in steps S105 and S107, and based on the vehicle speed or traffic volume of the other vehicle 2 in the adjacent lane 502 or the vehicle speed of the host vehicle 1, etc., it is determined that the lane change will be completed by the end of the recommended areas 21 and 23 (step S108: Yes), the determination of whether to execute the lane change is made. Based on the determination of whether to execute the lane change by the lane change execution determination unit 105, the vehicle control unit 106 executes the lane change (step S109), and the process ends.

[0050] More specifically, in step S109, the vehicle control unit 106 controls each actuator 250 so as to change the lane of the host vehicle 1 from the host lane 501 to the adjacent lane 502. For example, based on the output of the external sensor 240, the vehicle control unit 106 sets a target trajectory and a target vehicle speed to enter the empty space between the other vehicles 2 traveling in the adjacent lane 502, and controls the accelerator actuator, the brake actuator, and the steering actuator so that the host vehicle 1 travels along these.

[0051] On the other hand, if the lane change execution determination unit 105 is driving through the non-recommended area 22, or if the lane change is not completed by the end of the recommended areas 21 and 23 (step S108: No), it determines that the lane change will not be performed in the recommended areas 21 and 23, and that the vehicle should proceed to the next recommended area (step S110), and terminates the process. In this case, the vehicle control process may be suspended until the vehicle enters the next recommended area.

[0052] As described above, in the vehicle control device 10 according to this embodiment, when the lane change necessity determination unit 103 determines that the vehicle 1 needs to change lanes, the recommended area setting unit 104 derives a non-recommended area 22 in which it is estimated that the distance between the vehicle and other vehicles 2 traveling in the adjacent lane 502 to the vehicle change destination will decrease, based on signal information acquired by the communication module 230 or the external sensor 240. The recommended area setting unit 104 further sets recommended areas 23 and 24 for lane changes before or after the non-recommended area 22. The vehicle control unit 106 is configured to perform control to carry out a lane change in the set recommended areas 23 and 24. This makes it possible to perform smooth vehicle control for lane changes according to the signal status.

[0053] (Embodiment 2) The vehicle control device 10 according to Embodiment 2 of the present invention is a device that controls the lane change of the vehicle 1, similar to Embodiment 1. The hardware configuration and overall functional configuration of the vehicle control device 10 according to this embodiment are the same as those of Embodiment 1, but the detailed operation of the recommended area setting unit 104 differs from that of Embodiment 1. In the recommended area setting unit 104 of the vehicle control device 10 according to Embodiment 1, a non-recommended area was derived according to the signal status of the next intersection, but in the recommended area setting unit 104 of the vehicle control device 10 according to Embodiment 2, a non-recommended area caused by an obstruction in the adjacent lane 502 to which the lane change is intended is derived.

[0054] The operation of the vehicle control device 10 according to this embodiment will be described in detail with reference to Figures 8 and 9. Figure 8 is an example of a flowchart of the vehicle control processing performed by the vehicle control device 10 according to this embodiment. The processing shown in the flowchart of Figure 8 is performed in parallel with other vehicle control processing such as lane keeping control processing and collision avoidance processing, for example, at predetermined time intervals. Figure 9 is a diagram showing an example of lane change when there is an obstacle in the adjacent lane 502 to which the lane change is intended.

[0055] First, the vehicle position estimation unit 101 estimates the position of the vehicle 1 on the map in the map database 220 (vehicle position) based on the output signal of the position information acquisition unit 210, and the map information acquisition unit 102 acquires map information within a predetermined range including the estimated position of the vehicle 1 from the map database 220. Based on the acquired map information or the information received by the communication module 230, the lane change necessity determination unit 103 determines whether or not a lane change is necessary (step S101).

[0056] For example, when the communication module 230 receives traffic information from the infrastructure camera regarding lane closure, congestion, accidents, breakdowns, fallen objects, construction, etc. in the vehicle's own lane 501, the lane change necessity determination unit 103 determines that a lane change to the adjacent lane 502 is required. Alternatively, the lane change necessity determination unit 103 determines, based on the route information of the car navigation system, whether a lane change is required to turn right or left at the intersection ahead of the vehicle 1.

[0057] The example shown in Figure 9 illustrates a scenario in which vehicle 1, traveling in the rightmost lane 501, changes lanes to the adjacent lane 502 and then to the leftmost left-turn lane 503 in order to make a left turn in the future, based on route information from the car navigation system. In this example, the lane change necessity determination unit 103 determines that a lane change is necessary based on the route information (Step S101: Yes). On the other hand, if it is determined that a lane change is not necessary (Step S101: No), the process ends.

[0058] If it is determined that a lane change is necessary (Step S101: Yes), the recommended area setting unit 104 acquires traffic information including the road conditions of the adjacent lane 502 to which the lane change will take place (Step S112). The traffic information acquired is, for example, information received by the communication module 230 from a server or roadside equipment such as an infrastructure camera, and includes information indicating the presence or absence of obstacles 40 such as lane blockage, broken-down vehicles, accident vehicles, fallen objects, and construction in the adjacent lane 502. The example in Figure 9 shows a case where the obstacle 40 is a fallen object.

[0059] If the traffic information obtained in step S102 indicates that there is no obstacle 40 in the adjacent lane 502 to which the vehicle 1 is changing lanes (step S113: No), then it is predicted that the distance between vehicles 2 in the adjacent lane 502 to which the vehicle 1 is changing lanes has not decreased. For this reason, the recommended area setting unit 104 sets an area within a predetermined distance from the location where the vehicle 1 is currently located, where it has been confirmed that there is no obstacle, as the recommended area 21 (step S105), and proceeds to step S108.

[0060] On the other hand, if the traffic information acquired in step S102 indicates that there is an obstacle 40 on the road of the adjacent lane 502 as illustrated in Figure 9 (step S113: Yes), it is expected that the distance between vehicles 2 behind the obstacle 40 in the adjacent lane 502 will decrease. For this reason, the recommended area setting unit 104 derives an area with a distance from the obstacle of length d or less as a non-recommended area 41 that is unsuitable for lane changes due to the decrease in the distance between vehicles at the destination lane (step S106).

[0061] Here, the length d of the non-recommended area 41 in the direction of travel may be derived as a longer value the more traffic volume there is on the road being traveled. Alternatively, the length d may be derived as a longer value the faster the average speed of the vehicles traveling on the road. Alternatively, the length d may be derived as a longer time elapsed since the occurrence of the obstacle.

[0062] The recommended area setting unit 104 sets recommended areas other than the non-recommended area 41 derived in step S106. Specifically, the recommended area setting unit 104 sets the area before the non-recommended area 41 as recommended area 42 and the area beyond the obstacle 40 as recommended area 43 (step S107). Here, based on the output of the external sensor 240 or map information, sections that are determined to be unsuitable for lane changes or where lane changes are prohibited, such as within an intersection or in a section with a yellow lane marking, are not included in recommended areas 42 and 43.

[0063] Next, the lane change execution determination unit 105 determines whether to perform a lane change if the vehicle 1 is traveling through the recommended area 42 set in steps S105 and S107, and if it determines that the lane change will be completed by the end of the recommended area 42 based on the speed or traffic volume of other vehicles 2 in the adjacent lane 502 or the speed of the vehicle 1 (step S108: Yes). Based on the lane change execution determination unit 105's determination to perform a lane change, the vehicle control unit 106 performs the lane change (step S109), and the process ends.

[0064] More specifically, in step S109, the vehicle control unit 106 controls each actuator 250 to change the vehicle 1 from its own lane 501 to the adjacent lane 502. For example, based on the output of the external sensor 240, the vehicle control unit 106 sets a target trajectory and target speed to enter the open space between other vehicles 2 traveling in the adjacent lane 502, and controls the accelerator actuator, brake actuator, and steering actuator so that the vehicle 1 travels along these. In the example in Figure 9, if it is determined that the lane change will be completed by the end of the recommended area 42, the lane change to the central adjacent lane 502 will be performed within the recommended area 42 as shown in route 601.

[0065] On the other hand, if the lane change execution determination unit 105 is driving through the non-recommended area 41, or if the lane change is not completed by the end of the recommended area 42 (step S108: No), it determines that the lane change will not be performed in the recommended area 42 and that the vehicle should proceed to the next recommended area (step S110), and terminates the process. In this case, the vehicle control process may be suspended until the vehicle enters the next recommended area. In the example in Figure 9, if it is determined that the lane change will not be completed by the end of the recommended area 42, the vehicle will change lanes to the adjacent central lane 502 within the recommended area 43, as shown in route 602. Similarly, lane changes will be performed sequentially, and the vehicle 1 will be able to reach the left-turn lane 503.

[0066] As described above, in the vehicle control device 10 according to this embodiment, when the lane change necessity determination unit 103 determines that the vehicle 1 needs to change lanes, the communication module 230 acquires traffic information including the road conditions of the adjacent lane 502 to which the vehicle will change lanes, and the recommended area setting unit 104 derives a non-recommended area 41 in which it is estimated that the distance between the vehicle and other vehicles 2 traveling in the adjacent lane 502 to which the vehicle will change lanes will decrease due to an obstacle, and sets recommended areas 42 and 43 for lane changes before or after the non-recommended area 41. The vehicle control unit 106 is configured to perform control to carry out a lane change in the set recommended areas 42 and 43. This makes it possible to perform smooth vehicle control for lane changes according to road conditions.

[0067] (Modified Version) The above embodiment can be modified in various ways. Figure 10 is a part of the flowchart of the vehicle control process according to the modified version.

[0068] In step S108 of the flowcharts in Figures 7 and 8 of the above embodiments 1 and 2, the vehicle control device 10 determines that if it is traveling through the non-recommended areas 22 and 41 or if the lane change is not completed within the recommended areas 21, 23, and 42 (step S108: No), it proceeds to the next recommended area. In contrast, the vehicle control device 10 according to this modified example takes into account the events that caused it to be determined in step S101 that a lane change is required, and performs processing to ensure that the lane change is completed by the point where the lane change of the vehicle 1 is required to be completed.

[0069] Specifically, if there is an obstacle in the lane 501 that the vehicle 1 is traveling in, it is necessary to complete the lane change before reaching the obstacle in order to avoid it. Also, as illustrated in Figure 9, if the route information indicates a left turn, it is necessary to complete the lane change before reaching the point where the left turn will occur. Therefore, the vehicle control device 10 in this modified example performs a lane change at a shorter distance than the normal lane change distance and completes the lane change within the recommended area when the distance to the point where the lane change is to be completed or the number of sections between intersections is insufficient.

[0070] The hardware configuration and overall functional configuration of the vehicle control device 10 in this modified example are the same as in Embodiments 1 and 2, and the operation of the vehicle control device 10 is also the same as in Embodiments 1 and 2 up to step S107 in the flowcharts of Figures 7 and 8. The operation after steps S105 and S107 will be explained in accordance with the flowchart in Figure 10.

[0071] If the vehicle control device 10 determines that the vehicle 1 is traveling in the recommended areas 21, 23, and 42 set in steps S105 and S107 and that the lane change can be completed within the recommended areas 21, 23, and 42 (step S108: Yes), it performs a lane change in the recommended areas 21, 23, and 42 (step S109). On the other hand, if the vehicle control device 10 determines that the vehicle is traveling in the non-recommended areas 22 and 41 or that the lane change cannot be completed within the recommended areas 21, 23, and 42 (step S108: No), it proceeds to step S121.

[0072] If vehicle 1 is traveling in non-recommended areas 22 and 41 (step S121: Yes), the system proceeds to the next recommended areas 24 and 43 (step S110). If it is determined that the lane change cannot be completed within the recommended areas 21, 23, and 42 using the target trajectory of a normal lane change as performed in step S109 (step S108: No, step S121: No), the system determines whether there is sufficient distance to a predetermined point before the event that caused the lane change to be required in step S101. More specifically, the system determines whether the distance to the point where the lane change is completed is below a threshold (step S122).

[0073] If the distance to the point where the lane change is completed is below a threshold (Step S122: Yes), the vehicle control unit 106 performs the lane change in the recommended areas 21, 23, and 42 where the vehicle 1 is located at that time. Specifically, the vehicle control unit 106 performs the lane change with a target trajectory that has a higher curvature than the target trajectory of a normal lane change performed in Step S109 (Step S123). An upper limit may be set on the curvature of the target trajectory, and the vehicle may proceed to the next recommended area without performing a lane change with a curvature exceeding the upper limit.

[0074] If the distance to the point where the lane change is completed exceeds a threshold (step S122: No), the vehicle control unit 106 controls the vehicle to proceed to the next recommended area (step S110) because the objective of avoiding obstacles can be achieved by changing lanes in the next recommended area (step S110), and the process ends.

[0075] As explained above, in the vehicle control device 10 according to this modified example, in order to complete the lane change before the event that causes the determination to require a lane change, if the distance to the point where the lane change will be completed is below a threshold, the vehicle 1 will perform the lane change in the recommended areas 21, 23, and 42 where it is located at that time, using a target trajectory with a high curvature. This increases the likelihood of completing the lane change before reaching the point where the event that causes the determination to require a lane change occurs.

[0076] In this modified example, step S122 determines whether the distance to the point where the lane change is completed is below a threshold. However, instead, in the configuration of setting recommended areas based on signal information in Embodiment 1, it is also possible to determine whether the number of sections between intersections to the point where the lane change is completed is below a threshold. That is, if the number of sections between intersections to the point where the lane change is completed is below a threshold (corresponding to step S122: Yes), the vehicle 1 may perform a lane change on a target trajectory with a high curvature in the recommended areas 21, 23, and 42 where it is located at that time (step S123). Also, if the number of sections between intersections to the point where the lane change is completed exceeds a threshold (corresponding to step S122: No), the vehicle control unit 106 may control the vehicle to proceed to the next recommended area (step S110).

[0077] The hardware configuration and flowcharts shown in the above embodiments and modifications are examples only and can be arbitrarily changed or adapted. For example, the flowchart shown in Figure 7 of Embodiment 1 shows the case where the communication module 230 can receive signal information including the timing of signal changes from a server or roadside unit, but it can also be applied when the communication module 230 cannot receive signal information including the timing of signal changes. Figure 11 is a flowchart of the vehicle control process when the timing of signal changes cannot be obtained. As shown in Figure 11, after obtaining signal information for the next intersection by the external sensor 240 (step S102), in step S133, the recommended area 21 from the position of the vehicle 1 to the intersection may be set based only on the fact that the traffic light 31 at the next intersection is a proceed signal (step S133: Yes) (step S105). The other processes are the same as in Figure 7.

[0078] Furthermore, in the above embodiment 2, the recommended area setting unit 104 derives an area behind the obstacle 40 and at a distance of length d or less from the obstacle 40 as a non-recommended area 41 when there is an obstacle 40 in the adjacent lane 502 to which the vehicle is changing lanes. However, it is not limited to this, and a non-recommended area 41 may be derived based on other factors. If there is a change in the speed limit on the road being driven, where the speed limit is lowered, the recommended area setting unit 104 may derive an area behind the change in speed limit and at a distance of length d or less from the said location as a non-recommended area 41. This makes it possible to change lanes while avoiding areas where the distance between vehicles decreases due to the change in the speed limit.

[0079] Furthermore, although the above embodiment describes an example in which each function is realized by the processor 1011 executing a control program, the vehicle control device 10 may also be configured with dedicated hardware to realize each function.

[0080] Furthermore, the vehicle control device 10 may be configured to realize each function by distributing a control program for executing the operations of the above embodiment on a recording medium such as a computer-readable CD-ROM (Compact Disc Read-Only Memory), DVD (Digital Versatile Disc), MO (Magneto Optical Disc), or memory card, and installing the program on a computer. In cases where each function is realized through a division of labor between the OS (Operating System) and an application, or through cooperation between the OS and an application, only the parts other than the OS may be stored on the recording medium.

[0081] The present invention allows for various embodiments and modifications without departing from the broad spirit and scope of the invention. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of the invention. In other words, the scope of the invention is indicated by the claims, not by the embodiments. Various modifications made within the scope of the claims and the equivalent significance of disclosure are considered to be within the scope of the invention.

[0082] 1 Own vehicle, 2 Other vehicles, 10 Vehicle control device, 21, 23, 24, 42, 43 Recommended area, 22, 41 Non-recommended area, 31 Traffic light, 40 Obstacle, 100 Controller, 101 Own vehicle position estimation unit, 102 Map information acquisition unit, 103 Lane change necessity determination unit, 104 Estimation area setting unit, 105 Lane change execution determination unit, 106 Vehicle control unit, 210 Position information acquisition unit, 220 Map database, 230 Communication module, 240 Outside sensor, 250 Actuator, 1010 Bus, 1011 Processor, 1012 Storage device, 1013 Communication interface, 501 Own lane, 502 Adjacent lane, 503 Left-turn lane, 601, 602 Route.

Claims

1. A vehicle control method for controlling a vehicle's lane change, wherein when it is determined that the vehicle needs to change lanes, the method derives a non-recommended area where it is estimated that the distance between vehicles traveling in the adjacent lane to the lane change destination will decrease, based on signal information relating to a signal ahead of the vehicle or traffic information relating to the road on which the vehicle is traveling, and performs the lane change in a recommended area set outside the non-recommended area.

2. The vehicle control method according to claim 1, wherein the non-recommended area is inferred based on the fact that the signal at the next intersection in the direction of travel of the vehicle indicated by the signal information is a stop signal, or the timing at which the signal at the intersection changes to a stop signal, and the recommended area is an area set before the non-recommended area or after the intersection.

3. The vehicle control method according to claim 2, wherein the traffic volume, which is the number of vehicles passing through the intersection per unit time, is obtained, and a longer value is derived as the length of the non-recommended area in the direction of travel, the greater the traffic volume.

4. The vehicle control method according to claim 2 or 3, wherein the average vehicle speed of vehicles passing through the intersection is obtained, and the length of the non-recommended area in the direction of travel is derived to be longer as the average vehicle speed increases.

5. The vehicle control method according to any one of claims 2 to 4, wherein, when the signal information indicates that the signal at the intersection is a stop signal or will change to a stop signal within a predetermined first hour, the non-recommended area is derived as the area from the point where the following distance between other vehicles traveling in the adjacent lane to which the lane change will occur begins to decrease, up to the intersection.

6. The vehicle control method according to any one of claims 2 to 5, wherein when the signal at the intersection indicated by the signal information is a stop signal, the longer the elapsed time since the signal at the intersection became a stop signal, the longer the distance from the intersection is identified as the non-recommended area.

7. The vehicle control method according to any one of claims 2 to 6, wherein, when the signal at the intersection indicated by the signal information is a stop signal, the area further from the intersection is identified as the unrecommended area, the greater the number of vehicles stopped at the intersection per unit time.

8. The vehicle control method according to any one of claims 2 to 7, wherein the unrecommended area is deactivated after a predetermined second time has elapsed since the signal at the intersection indicated by the signal information changed from a stop signal to a proceed signal, and the second time is set to be longer the longer the distance from the intersection to the position of the vehicle that stopped when the signal at the intersection indicated by the signal information was a stop signal.

9. The vehicle control method according to any one of claims 1 to 8, wherein the area derived as the non-recommended area is an area in which the distance between vehicles traveling in the adjacent lane to which the vehicle is changing lanes is shorter than a predetermined threshold.

10. The vehicle control method according to any one of claims 1 to 8, wherein the area derived as the non-recommended area is an area in which the distance between vehicles traveling in the adjacent lane to which the lane change is intended is shorter than the average value of the distance between vehicles obtained in advance.

11. The vehicle control method according to claim 1, wherein, when the traffic information indicates that there is an obstruction in the adjacent lane to which the lane change is intended, a non-recommended area is derived in which it is estimated that the distance between other vehicles traveling in the adjacent lane will decrease behind the obstruction.

12. The vehicle control method according to claim 1, wherein, when the traffic information indicates that there is a point on the road ahead of the vehicle where the speed limit is reduced, the vehicle derives a non-recommended area behind the point where the speed limit is reduced, in which it is estimated that the distance between other vehicles traveling in the adjacent lane will decrease.

13. A vehicle control method according to any one of claims 1 to 12, wherein if the vehicle is located within the recommended area, the lane change is performed if the lane change can be completed within the recommended area, and if the lane change cannot be completed within the recommended area, the lane change is performed within the recommended area set beyond the non-recommended area.

14. A vehicle control method according to any one of claims 1 to 13, wherein if the distance to the point where the lane change of the vehicle is required to be completed, or the number of sections between intersections to the point where the lane change is completed, is less than or equal to a predetermined threshold, the vehicle performs the lane change at a shorter distance than the normal lane change distance and completes the lane change within the recommended area.

15. A vehicle control device comprising: a communication module or external sensor that acquires signal information relating to a signal in front of the vehicle or traffic information relating to the road on which the vehicle is traveling; and a processor that, when it is determined that the vehicle needs to change lanes, derives an unrecommended area where it is estimated that the distance between vehicles traveling in the adjacent lane to the lane change destination will decrease based on the signal information or traffic information acquired by the communication module or external sensor, and controls the vehicle to perform the lane change in a recommended area set outside the unrecommended area.

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