Vehicle control device and vehicle control method

Abstract

In one aspect of a vehicle control device and a vehicle control method according to the present invention, when a vehicle stop maintenance function of a vehicle fails, a flat vehicle stopping candidate location where the vehicle can stop, which is searched for on the basis of external information of the vehicle, the cruising range of the vehicle, and the traffic conditions around the vehicle, is obtained, and the flat vehicle stopping candidate location is set as a destination of a target route along which the vehicle is caused to automatically travel. This configuration makes it possible to stop a vehicle in a state in which safety is ensured, even if a vehicle stop maintenance function of the vehicle fails on a public road.

Description

Vehicle control device and vehicle control method

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

[0002] The automatic parking system of Patent Document 1 is an automatic parking system that can instruct an automatically driven vehicle to retreat to an appropriate retreat space depending on the type of failure.If the type of failure is a brake abnormality, the retreat space is a flat location that the automatically driven vehicle can reach without going over a ramp.

[0003] Japanese Patent Application Laid-Open No. 2021-068304

[0004] Incidentally, if the vehicle's stop maintenance function fails in a vehicle that drives automatically on public roads, when the vehicle stops on a slope and ceases operation, it may not be possible to prevent the vehicle from sliding downward along the slope, which could result in a loss of vehicle safety. The stop maintenance function is a function that prevents the vehicle from moving even when the vehicle system is stopped by mechanically locking the movement of the wheels or by fixing the wheels in a state in which a braking force is applied, and in the case of a vehicle that drives automatically, this is realized, for example, by an automatic parking lock mechanism such as an automatic P-range shift, or an electric parking brake.

[0005] The present invention has been made in consideration of the current situation, and its purpose is to provide a vehicle control device and a vehicle control method that can stop a vehicle in a safe manner even if the vehicle's stop maintenance function fails on a public road.

[0006] In one aspect, the vehicle control device of the present invention includes a vehicle stop maintenance function determination unit that determines a failure of the vehicle's vehicle stop maintenance function, a destination setting unit that, when the vehicle stop maintenance function is determined to be failed, acquires flat candidate stopping locations where the vehicle can stop, searched based on external information about the vehicle, the vehicle's cruising range, and traffic conditions around the vehicle, and sets the flat candidate stopping locations as a destination of a target route along which the vehicle will automatically travel, and a vehicle control unit that automatically travels the vehicle along the target route to the destination and stops the vehicle at the destination.

[0007] In one aspect, the vehicle control method of the present invention determines whether a vehicle's vehicle stop maintenance function has failed, and if the vehicle stop maintenance function is determined to have failed, obtains flat candidate stopping locations where the vehicle can stop, searched for based on external information about the vehicle, the vehicle's cruising range, and traffic conditions around the vehicle, sets the flat candidate stopping location as a destination of a target route along which the vehicle will automatically travel, causes the vehicle to automatically travel along the target route to the destination, and stops the vehicle at the destination.

[0008] According to the above invention, even if the vehicle's stop maintaining function breaks down on a public road, the vehicle can be stopped in a state where safety is ensured.

[0009] 1 is a block diagram showing one aspect of a vehicle control system. FIG. 2 is a diagram for outlining setting of a destination when a vehicle stop maintenance function has failed. FIG. 3 is a diagram showing a state in which it is determined that stopping is impossible due to an obstacle. FIG. 4 is a diagram showing a state in which it is determined that stopping is impossible due to a gradient. FIG. 5 is a flowchart showing the flow of stopping control when a vehicle stop maintenance function has failed. FIG. 6 is a diagram illustrating criteria for setting the priority of candidate stopping locations. FIG. 7 is a flowchart showing the flow of stopping control when a flat candidate stopping location cannot be found. FIG. 8 is a diagram showing a state in which a vehicle is stopped sideways on a slope. FIG. 9 is a block diagram showing one aspect of a remote control system. FIG. 10 is a flowchart showing the flow of a process for searching for candidate stopping locations in a remote control center. FIG. 11 is a flowchart showing the flow of stopping control that a vehicle control device performs by acquiring information on candidate stopping locations from the remote control center.

[0010] Hereinafter, an embodiment of a vehicle control device and a vehicle control method according to the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing one aspect of a vehicle system 200. The vehicle system 200 is a system mounted on a vehicle 100, such as a four-wheeled automobile, for controlling the movement of the vehicle 100, and has a configuration capable of realizing autonomous driving.

[0011] The vehicle system 200 includes an external environment recognition unit 300, a vehicle information detection unit 400, a vehicle control device 500, a traveling actuator unit 600, and a vehicle stop maintaining device 700. The vehicle control device 500 is an electronic control device that includes, as a control unit, a microcomputer 510 having a processor that executes programs such as a CPU (Central Processing Unit), a memory, and an input / output interface.

[0012] The applications implemented in microcomputer 510 include an application that realizes an autonomous driving function, and further includes an application that realizes a fail-safe function when the vehicle 100's vehicle stop maintenance function fails while traveling on a public road. In other words, microcomputer 510 executes a vehicle control method that realizes a fail-safe function when the vehicle stop maintenance function fails. Vehicle system 200 is configured to be able to realize Level 4 autonomous driving, in which the system performs all driving tasks under specific conditions, or Level 5, in which the system always performs all driving tasks.

[0013] The external environment recognition unit 300 includes, for example, a GPS (Global Positioning System) receiving unit 310, a map database 320, a road-to-vehicle communication device 330, a camera 340, a radar 350, and a LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) 360. The external environment recognition unit 300 acquires external environment information of the vehicle 100, including map information and information on traffic conditions around the vehicle 100, in other words, information on the driving environment of the vehicle 100, using the above-mentioned devices.

[0014] The GPS receiver 310 receives signals from GPS satellites to measure the latitude and longitude of the location of the vehicle 100. The map database 320 is a collection of map information including road locations, road shapes, intersection locations, etc., and is created in a storage device installed in the vehicle 100.

[0015] The road-to-vehicle communication device 330 is a communication device for transmitting information about the vehicle 100 to a roadside device and receiving road traffic information such as information about curves, intersections, and congestion from the roadside device. The external environment recognition unit 300 may include a vehicle-to-vehicle communication device that communicates between the vehicle 100 (the vehicle itself) and other vehicles and acquires road traffic information, behavior information of other vehicles, and the like from the other vehicles with which the communication is made.

[0016] The camera 340 is a stereo camera, a monocular camera, a 360° camera, or the like, and captures images of the surroundings of the vehicle 100 to acquire image information of the surroundings of the vehicle 100. The radar 350 and the LiDAR 360 detect objects around the vehicle 100 and output information about the detected objects.

[0017] The vehicle information detection unit 400 includes a wheel speed sensor 410 that detects the rotational speed of each of the four wheels of the vehicle 100, a three-axis acceleration sensor 420 that detects three-dimensional inertial motion (translational motion in three orthogonal axial directions), and an inclination angle sensor 430 that detects the inclination angle of an axis that passes through the body of the vehicle from front to rear with respect to a horizontal plane. The traveling actuator unit 600 also includes a drive actuator 610 such as an internal combustion engine or a motor, a braking actuator 620 such as a hydraulic brake or a motor generator that generates regenerative torque, and a steering actuator 630 such as an electric power steering or steer-by-wire.

[0018] Furthermore, the vehicle stop maintaining device 700 is a functional unit that realizes a function of stopping the movement of the vehicle 100 when the vehicle system 200 is in a stopped state, and includes an electric parking brake 710 and a parking lock mechanism 720. The electric parking brake 710 is a device that activates the parking brake using an actuator.

[0019] The parking lock mechanism 720, for example, restricts the rotation of the output shaft of the transmission, and in turn restricts the rotation of the drive wheels of the vehicle 100, by fitting a protrusion whose position is adjusted by an actuator to a gear that is connected to a rotating element in the transmission that constitutes the power train of the vehicle 100. In other words, in the case of an automatic transmission vehicle (AT vehicle), the parking lock mechanism 720 realizes the function of automatically shifting the position of the shift lever to P range (parking range).

[0020] The vehicle control device 500 acquires external environment information recognized by the external environment recognition unit 300, vehicle information detected by the vehicle information detection unit 400, and the like, and plans a driving route and speed of the vehicle 100 based on the acquired various information. The vehicle control device 500 then calculates control commands for causing the vehicle 100 to follow the planned driving route and speed, specifically, steering commands (steering angle command, steering force command) and acceleration / deceleration commands (driving force command, braking force command), and outputs the calculated control commands to the actuators 610, 620, and 630 of the driving actuator unit 600, thereby realizing autonomous driving along the planned driving route and speed. Note that the autonomous driving control by the vehicle control device 500 includes, in addition to control of the driving actuator unit 600, control of the illumination of turn signal lamps (not shown) and operation control of the vehicle stop maintaining device 700.

[0021] Incidentally, when the vehicle 100 is automatically traveling on a public road, if the vehicle stop maintenance function using the vehicle stop maintenance device 700 fails and the vehicle 100 stops on a slope and stops operation in this failed state, the function to stop the movement of the vehicle 100 is lost, so the vehicle 100 may not be able to maintain the stopped state and may slide back. Therefore, the vehicle control device 500 has a fail-safe function that stops the vehicle 100 in a state in which sliding back is prevented, even if the vehicle stop maintenance function fails when the vehicle 100 is automatically traveling on a public road.

[0022] The fail-safe function is a function that, when the vehicle stop maintenance function fails, automatically drives and stops the vehicle 100 to a flat stopping area that is searched for based on map information, the cruising range of the vehicle 100, and the traffic conditions around the vehicle 100. In this way, by stopping the vehicle 100 on a flat stopping area, even if the vehicle stop maintenance function fails, it is possible to prevent the vehicle 100 from moving inadvertently while stopped, and it is possible to stop the vehicle 100 in a state where safety is ensured.

[0023] The microcomputer 510 of the vehicle control device 500 has, as functional units for realizing the above-mentioned fail-safe function, a vehicle stop maintenance function determination unit 511, a destination setting unit 512, a vehicle stop possibility re-determination unit 513, and a vehicle control unit 514. The vehicle stop maintenance function determination unit 511 determines a failure of the vehicle stop maintenance function using the vehicle stop maintenance device 700. A failure of the vehicle stop maintenance function is a state in which the electric parking brake 710 or the parking lock mechanism 720 has failed, making it impossible to activate the vehicle stop maintenance function and making it impossible to stop the movement of the vehicle 100 when the vehicle system 200 is stopped.

[0024] Here, the vehicle stop maintaining function determining unit 511 determines whether or not there is a malfunction in the vehicle stop maintaining device 700. Then, the vehicle stop maintaining function determining unit 511 transmits a signal indicating whether or not there is a malfunction in the vehicle stop maintaining function to the destination setting unit 512.

[0025] The vehicle stop maintenance function determination unit 511 constantly acquires diagnostic information that is the result of a fault diagnosis performed by another control device, and determines whether or not there is a fault in the vehicle stop maintenance function based on the acquired diagnostic information. In addition, the vehicle control device 500 (vehicle stop maintenance function determination unit 511) can also perform a fault diagnosis on the vehicle stop maintenance function.

[0026] When the vehicle stop maintenance function determination unit 511 determines that the vehicle stop maintenance function has failed, the destination setting unit 512 searches for a flat candidate stopping location where the vehicle 100 can stop, based on the external environment information of the vehicle 100, the cruising range of the vehicle 100, and the traffic conditions around the vehicle 100, and sets the searched flat candidate stopping location as a destination of the target route for automatic driving of the vehicle 100. In other words, even if the vehicle stop maintenance function has failed, stopping the vehicle 100 on flat ground can prevent the vehicle 100 from rolling back, and the vehicle 100 can be safely stopped. Therefore, the destination setting unit 512 searches for a flat location as a candidate stopping location where the vehicle 100 can be safely stopped even if the vehicle stop maintenance function has failed.

[0027] Here, the destination setting unit 512 searches for flat candidate stopping locations where the vehicle 100 can be stopped and within the cruising distance of the vehicle 100, based on external environment information including map information and the cruising distance. In other words, the destination setting unit 512 acquires external environment information for the vehicle 100 from the map information. Furthermore, the destination setting unit 512 narrows down the candidate stopping locations based on traffic conditions (traffic flow, traffic volume, etc.) around the vehicle 100 so that stopping of the vehicle 100 does not interfere with the travel of other vehicles on public roads.

[0028] Then, the destination setting unit 512 sets the narrowed down flat candidate stopping locations as the destination of the target route along which the vehicle 100 will automatically travel, and outputs information about the set destination to the vehicle control unit 514. The vehicle control unit 514 causes the vehicle 100 to automatically travel along the target route to the destination, and stops the vehicle 100 at the destination. Note that since this embodiment is intended for autonomous driving at level 4 or higher, the vehicle control unit 514 performs autonomous driving control including driving force control, braking force control, steering control, turn signal control, and the like.

[0029] 2 is a diagram illustrating how the destination setting unit 512 sets a destination on the condition that the destination is flat. For example, if the vehicle stop maintenance function fails while the vehicle 100 is automatically traveling uphill, the destination setting unit 512 sets flat ground at the top of the slope as a candidate stop location, automatically drives the vehicle 100 to this candidate stop location, and stops the vehicle 100 at the destination (flat ground) once the vehicle 100 reaches the destination. Here, because the destination is flat, even if the vehicle stop maintenance device 700, such as the electric parking brake 710 or the parking lock mechanism 720, does not operate, the vehicle 100 is prevented from sliding down the slope of the road surface, and the vehicle 100 can be safely stopped.

[0030] It is assumed that the map information used by the destination setting unit 512 to search for candidate stopping locations is high-precision three-dimensional map data (HD map). The map information preferably includes road gradient information. However, even if the map information does not include road gradient information, as long as the map information includes elevation information, the destination setting unit 512 can use the road gradient information calculated from the elevation information to search for candidate stopping locations. The vehicle information acquired by the destination setting unit 512 preferably includes the cruising range of the vehicle 100. However, the destination setting unit 512 can acquire information on the remaining fuel amount or remaining battery level of the vehicle 100 instead of the cruising range, and calculate the cruising range from the remaining fuel amount or remaining battery level, i.e., the distance that can be traveled with the remaining fuel amount or remaining battery level.

[0031] Furthermore, after the vehicle 100 is automatically driven to the destination under the automatic driving control of the vehicle control unit 514, the stopping possibility re-determination unit 513 re-determines whether the vehicle 100 can stop at the destination based on external environment information about the destination acquired by external environment recognition sensors such as the camera 340 and the radar 350 and vehicle information including specifications (total length, total width, etc.) of the vehicle 100. The stopping possibility re-determination unit 513 determines that the vehicle 100 cannot stop in cases such as when another vehicle is already parked at the destination, when an obstacle is present on the approach route to the target location and the destination cannot be reached, or when there is insufficient space to stop the vehicle 100.

[0032] In this way, when the vehicle 100 arrives at a destination that has been determined based on map information or the like to be able to stop, the stopping possibility re-determination unit 513 determines whether the vehicle 100 can actually stop by observing the destination. Then, the stopping possibility re-determination unit 513 transmits the result of the determination that the vehicle 100 cannot stop to the destination setting unit 512. The destination setting unit 512, which has received the determination result by the stopping possibility re-determination unit 513 that the vehicle 100 cannot stop, searches again for flat candidate stopping locations and sets a new destination.

[0033] 3 illustrates an example of a pattern in which the stopping possibility re-determination unit 513 determines that stopping of the vehicle 100 is not possible. The example illustrated in FIG. 3 illustrates a case in which the destination setting unit 512 sets a parking space provided on the side of a road as the destination.

[0034] In this case, when the vehicle 100 reaches the vicinity of the parking space that is the destination, the camera 340, radar 350, or the like mounted on the vehicle 100 recognizes that another vehicle is parked in the parking space (in other words, there is an obstacle at the destination) and there is no space to stop the vehicle 100, and the stopping possibility re-determination unit 513 determines that it is not possible to stop the vehicle 100. Based on this determination that it is not possible to stop, the destination location setting unit 512 sets a new destination location (a flat candidate stopping location), and the vehicle control unit 514 automatically drives the vehicle 100 toward this new destination location.

[0035] Furthermore, the stopping possibility re-determination unit 513 includes a gradient information acquisition unit 513A. The gradient information acquisition unit 513A acquires gradient information of the destination based on vehicle information including information from sensors equipped in the vehicle 100. Fig. 4 shows how gradient is estimated based on information from sensors equipped in the vehicle 100. When the vehicle 100 arrives near the destination, the gradient information acquisition unit 513 acquires, for example, an acceleration detection signal from the three-axis acceleration sensor 420 equipped in the vehicle 100, and can estimate the gradient of the destination from the acceleration detection signal.

[0036] If the stopping possibility re-determination unit 513 determines that the gradient of the destination that should have been searched for as flat ground is actually greater than a predetermined value due to an error in map information or the like, that is, if the destination that was determined to be flat ground is actually on a slope, it determines that it is not possible to stop the vehicle 100. Then, the stopping possibility re-determination unit 513 transmits the result of determining that it is not possible to stop the vehicle 100 to the destination location setting unit 512, and prompts the destination location setting unit 512 to reset the destination location.

[0037] If the destination is actually on a slope, parking the vehicle 100 at the destination may cause the vehicle 100 to slide down while stopped due to a malfunction of the vehicle stop maintenance function. Therefore, the stop possibility re-determination unit 513 causes the target place setting unit 512 to set another destination, and causes the vehicle 100 to stop at a destination that is actually flat.

[0038] The gradient information acquisition unit 513 can acquire gradient information of the destination based on the acceleration detected by the three-axis acceleration sensor 420, and if the vehicle 100 is equipped with an inclination angle sensor 430, can acquire gradient information directly from the inclination angle sensor 430. The gradient information acquisition unit 513 can also acquire gradient information based on image information of the surroundings of the vehicle 100 captured by the camera 340, or can acquire gradient information from an external source such as the road-to-vehicle communication device 330.

[0039] 5 is a flowchart showing the flow of automatic driving control (vehicle control method) when the vehicle stop maintenance function fails, which is performed by the microcomputer 510 of the vehicle control device 500. In step S801, the microcomputer 510 acquires diagnostic information of the vehicle 100, including the diagnostic results of the vehicle stop maintenance function.

[0040] Next, the microcomputer 510 determines whether or not the vehicle stop maintenance function has malfunctioned in step S802 (vehicle stop maintenance function determination unit 511). If the vehicle stop maintenance function is normal, the microcomputer 510 ends the processing, but if the vehicle stop maintenance function has malfunctioned, the microcomputer 510 proceeds to step S803.

[0041] In step S803, the microcomputer 510 starts searching for a flat candidate stopping location where the vehicle 100 can be stopped and that is within the cruising distance from the current position of the vehicle 100, based on the external environment information including map information and the cruising distance of the vehicle 100. In the next step S804, the microcomputer 510 determines whether a flat candidate stopping location has been found.

[0042] Here, flat ground as a candidate stopping location is not limited to a site with a gradient (inclination angle) of zero, but may have a gradient in a range that does not cause the vehicle 100 to roll down. Therefore, the microcomputer 510 compares the gradient of the candidate stopping location with a gradient threshold (gradient threshold > 0) that is set in advance based on the upper limit of the gradient at which the vehicle 100 does not roll down, and can determine that the candidate stopping location is flat if the gradient is equal to or less than the gradient threshold.

[0043] If the microcomputer 510 determines in step S804 that a flat candidate stopping location has been found, the process proceeds to step S805. On the other hand, if the microcomputer 510 determines in step S804 that a flat candidate stopping location has not been found, the process proceeds to step S813. The process in step S813 when a flat candidate stopping location has not been found will be described later.

[0044] When the microcomputer 510 proceeds to step S805 after successfully finding flat candidate stopping locations, it sets priorities for the found flat candidate stopping locations, taking into consideration the traffic conditions (traffic flow, traffic volume, etc.) around the vehicle 100. Fig. 6 shows an example of criteria for setting priorities for candidate stopping locations. Here, candidate stopping locations must satisfy three conditions: the location must be capable of stopping the vehicle 100, it must be located within the cruising range, and it must be a flat location.

[0045] Being able to stop the vehicle 100 means that the vehicle 100 is legally permitted to stop at a location, and private property or a location where parking is prohibited does not meet the conditions for a candidate stopping location. Furthermore, a location where the vehicle 100 must reach its destination and stop before it runs out of fuel or battery, and thus requires traveling a distance exceeding its cruising range, does not meet the conditions for a candidate stopping location. Furthermore, if the vehicle 100 is parked at a location with a slope due to a malfunction of the vehicle stop maintenance function, the vehicle 100 will roll back. Therefore, a candidate stopping location must be flat enough to prevent the vehicle from rolling back even if the vehicle stop maintenance function is malfunctioning. Therefore, a location with a slope of a certain level or greater does not meet the conditions for a candidate stopping location.

[0046] Furthermore, the microcomputer 510 sets a condition based on the traffic conditions around the vehicle 100 as a criterion for setting priorities for candidate stopping locations that satisfy the above three conditions. Specifically, the microcomputer 510 sets priorities for candidate stopping locations based on conditions such as not interfering with traffic flow, having little traffic, and being likely to receive rescue (easily receiving roadside assistance).

[0047] Here, the microcomputer 510 prioritizes the above three conditions based on traffic conditions in descending order of priority: "does not interfere with traffic flow," "light traffic volume," and "easy arrival of rescue teams," and assigns the highest priority to a candidate stopping location that satisfies the condition "does not interfere with traffic flow." The condition "does not interfere with traffic flow" means that the vehicle 100 does not interfere with the surrounding traffic flow after stopping the vehicle 100, and a candidate stopping location that does not interfere with traffic flow is set to have the highest priority. Potential candidate stopping locations that do not interfere with traffic flow include, for example, emergency lanes and service areas on expressways.

[0048] Furthermore, the condition of "low traffic volume" is a condition for vehicle 100 to not interfere with the surrounding traffic flow as much as possible after stopping vehicle 100, and a shoulder of a public road with low traffic volume, for example, satisfies this condition. When a candidate stopping location satisfies the condition of "low traffic volume," the candidate stopping location is set to have a higher priority than candidate stopping locations that satisfy the condition of "not interfering with traffic flow."

[0049] Furthermore, the condition "it is easy for rescue to arrive" is determined based on the distance from the rescue base to the candidate stopping location, etc. Since the vehicle 100 makes an emergency evacuation stop due to a failure of the vehicle stop maintenance function, it is necessary for rescue to repair the malfunctioning part and tow the vehicle 100 after the vehicle stops, so it is preferable to satisfy the condition "it is easy for rescue to arrive" in order to shorten the time that the vehicle 100 waits in a stopped state as much as possible.

[0050] Therefore, if a candidate stopping location satisfies the condition that "it is easy for rescue to arrive," the microcomputer 510 assigns a lower priority to the candidate stopping locations than the conditions that "there is little traffic volume" and "it does not interfere with traffic flow," but assigns the next highest priority to these. In this way, in step S805, the microcomputer 510 assigns a priority to each candidate stopping location that satisfies all three conditions of being able to stop the vehicle 100, being located within the cruising range, and being a flat location, depending on whether it "does not interfere with traffic flow," "has little traffic volume," or "it is easy for rescue to arrive."

[0051] Note that the setting of the priority of the candidate stop locations is not limited to the setting based on the traffic conditions around the vehicle 100. For example, the microcomputer 510 can set the priority of the candidate stop locations based on the distance from the current position of the vehicle 100 to the candidate stop locations, the positional relationship between the candidate stop locations and the target route to the original destination, such as whether the candidate stop locations are located on the way to the original destination, the communication environment at the candidate stop locations, the distance from the candidate stop locations to service facilities such as toilets, gas stations, and charging facilities, the ease of access to alternative transportation means such as public transportation, and the like.

[0052] In step S805 (destination setting unit 512), microcomputer 510 prioritizes the candidate stopping locations, and then in the next step S806, sets the candidate stopping location with the highest priority as the destination of the target route for automatically driving vehicle 100. After setting the destination of the target route for automatically driving vehicle 100, microcomputer 510 controls travel actuator unit 600 in step S807 (vehicle control unit 514) to cause vehicle 100 to automatically drive along the target route to the destination.

[0053] When the vehicle 100 moves close to the destination, in step S808, the microcomputer 510 acquires external environment information for the vehicle 100, including information about obstacles, using the camera 340, radar 350, etc. of the external environment recognition unit 300. Furthermore, in the next step S809 (gradient information acquisition unit 513A), the microcomputer 510 acquires actual gradient information of the destination using the three-axis acceleration sensor 420 or the tilt angle sensor 430, etc.

[0054] Then, in step S810 (stopping possibility re-determination unit 513), microcomputer 510 re-determines whether vehicle 100 can be safely stopped at the destination based on the acquired external environment information of vehicle 100 and actual gradient information of the destination. Here, microcomputer 510 determines that vehicle 100 cannot be stopped at the destination if an obstacle, such as another vehicle stopped ahead, exists at the destination.

[0055] Furthermore, if the actual gradient of the destination differs from gradient information obtained from map information or the like and is equal to or greater than a predetermined value, microcomputer 510 determines that vehicle 100 cannot stop at the destination. On the other hand, if there are no obstacles at the destination and the actual gradient of the destination is less than a predetermined value, like gradient information obtained from map information or the like, microcomputer 510 determines that vehicle 100 can stop at the destination.

[0056] If the microcomputer 510 determines that the vehicle 100 can be stopped at the destination, the process proceeds to step S811, where the vehicle 100 is moved to the destination and stopped there. Next, in step S812, the microcomputer 510 turns on the hazard lights to notify other vehicles traveling nearby that the vehicle 100 will be stopped due to a malfunction. On the other hand, if the microcomputer 510 determines that the vehicle 100 cannot be stopped at the destination, the process returns to step S803, where the microcomputer 510 searches for a candidate stopping location other than the destination where the vehicle 100 was attempted to be stopped.

[0057] According to the above embodiment, when the vehicle stop maintenance function (vehicle stop maintenance device 700) of the vehicle 100 that is automatically driven on a public road fails, the vehicle 100 can be stopped on a flat place avoiding slopes, so that even if the vehicle stop maintenance function does not operate normally, the vehicle 100 can be stopped in a state where rolling over of the vehicle 100 is prevented. Therefore, the vehicle 100 can be maintained in a safe stopped state where rolling over of the vehicle is prevented without providing a redundant electric parking brake 710 or the like.

[0058] Fig. 7 is a flowchart showing the flow of stopping control when a flat candidate stopping location cannot be found, which is executed in step S813 of the flowchart in Fig. 5. In step S814, microcomputer 510 executes a search for a candidate stopping location, but excludes the condition of a flat location, and searches for a candidate stopping location that is possible for stopping, is within the cruising range, and has a predetermined size or more, based on map information and vehicle information including specifications of vehicle 100 (overall length, overall width, minimum turning radius, etc.).

[0059] In other words, since the microcomputer 510 was unable to find a flat candidate stopping site, it expands the search range to include sloping land. Here, the condition of having a predetermined or greater area means that the area is large enough to allow the vehicle 100 to be parked so that its left-right direction is aligned with the slope of the lot (hereinafter referred to as "sideways parking"), and that parking the vehicle 100 sideways will not interfere with the surrounding traffic flow. The area required for a candidate stopping site varies depending on the specifications related to the size of the vehicle 100, and the microcomputer 510 determines the suitability of the candidate stopping site by comparing the size of the vehicle 100 with the shape and area of ​​the candidate stopping site.

[0060] In this way, if the microcomputer 510 is unable to find a flat candidate stopping location, the microcomputer 510 proceeds to step S813 and searches for a location where the vehicle 100 can be stopped sideways even if there is an incline, as a candidate stopping location, based on the map information and the vehicle information including the specifications of the vehicle 100. The location that the microcomputer 510 searches for as a candidate stopping location in step S814 is likely to be a large, open space with an incline.

[0061] Figure 8 shows a state in which the vehicle 100 is parked sideways. In the example shown in Figure 8, the lot has a downward slope to the left in Figure 8, and the vehicle 100 is parked so that the direction perpendicular to the plane of the page is the front-to-rear direction. In this case, the traveling direction of the vehicle 100 (in other words, the direction of the tires) and the direction of the slope are perpendicular to each other, so that the vehicle 100 can be prevented from sliding down.

[0062] When the microcomputer 510 has searched for a candidate stopping location in step S814, the microcomputer 510 proceeds to step S815 to determine whether or not a candidate stopping location that is possible for stopping, within the cruising distance, and has a predetermined size or more (hereinafter referred to as a "candidate stopping location with an incline") has been found. If the microcomputer 510 determines in step S815 that a candidate stopping location with an incline has been found, the microcomputer 510 proceeds to step S816 (destination setting unit 512).

[0063] In step S816, the microcomputer 510 sets the searched stopping candidate location having an incline as the destination of the target route for automatic travel of the vehicle 100. Note that even when searching for a stopping candidate location having an incline, the microcomputer 510 can set priorities in consideration of the traffic conditions around the vehicle 100 (traffic flow, traffic volume, etc.), and set the stopping candidate location with the highest priority as the destination.

[0064] Next, in step S817 (vehicle control unit 514), microcomputer 510 automatically drives vehicle 100 along the target route to the destination. When vehicle 100 reaches the vicinity of the destination, microcomputer 510 turns on the hazard lights of vehicle 100 before stopping vehicle 100 at the destination.

[0065] That is, when stopping vehicle 100 sideways, the movement of vehicle 100 is often large, so by turning on the hazard lights in advance and then stopping vehicle 100 sideways, attention is drawn to the surroundings regarding the operation of stopping vehicle 100 sideways. Then, after turning on the hazard lights, microcomputer 510 stops vehicle 100 sideways at the destination in step S818 (vehicle control unit 514). In this way, even if a flat candidate stopping site cannot be found, microcomputer 510 stops vehicle 100 sideways at a candidate stopping site with an incline, thereby enabling the vehicle to stop in a state in which rolling down is prevented.

[0066] Even when a candidate stopping location with an incline is set as the destination, when the microcomputer 510 reaches the vicinity of the destination, it can re-determine whether or not the vehicle 100 can stop, based on external information including information about the presence of obstacles and specifications of the vehicle 100 including information about the size of the vehicle 100. If the microcomputer 510 determines that stopping is not possible, it re-searches for a candidate stopping location with an incline and sets a new destination.

[0067] On the other hand, if microcomputer 510 determines in step S815 that it was unable to find a candidate stopping location with an incline, it proceeds to step S819 and sets a location where immediate stopping is possible as the destination. In other words, if microcomputer 510 cannot find a candidate stopping location that is flat and also cannot find a candidate stopping location with an incline that allows sideways stopping, it sets, for example, a shoulder of the road ahead of the travel path as the destination of the target route for automatic travel of vehicle 100.

[0068] Then, in the next step S820 (vehicle control unit 514), microcomputer 510 automatically drives vehicle 100 along the target route to the destination and stops vehicle 100 at the destination. Next, in step S821, microcomputer 510 turns on the hazard lights of vehicle 100 to notify other vehicles traveling nearby that the vehicle has stopped due to a malfunction.

[0069] Incidentally, instead of searching for candidate stopping locations by itself, the microcomputer 510 (destination setting unit 512) can acquire information about candidate stopping locations via communication from outside the vehicle 100. For example, when the vehicle 100 is remotely controlled (or remotely assisted or remotely monitored), the remote control process can search for flat candidate stopping locations and transmit information about the searched flat candidate stopping locations to the vehicle 100.

[0070] Figure 9 is a block diagram showing one embodiment of a remote control system. In Figure 9, blocks that are the same as those in Figure 1 are assigned the same reference numerals, and detailed descriptions thereof will be omitted. The vehicle control device 500 includes a communication device 520 for communicating with a management server 910 (computer) of a remote control center 900 provided outside the vehicle 100 via a communication network 920, and the microcomputer 510 (destination setting unit 512) and the management server 910 are configured to be able to communicate with each other.

[0071] When it is determined that the vehicle 100's vehicle stop maintenance function has failed, the microcomputer 510 (destination setting unit 512) transmits a vehicle stop request signal (in other words, a signal requesting transmission of information on candidate stopping locations) to the management server 910. The management server 910 also acquires driving data such as external information about the vehicle 100 (such as images captured by the camera 340) and information on the vehicle 100's cruising range through communication with the vehicle control device 500.

[0072] When the management server 910 receives a stop request signal from the vehicle 100, it presents the stop request signal from the vehicle 100 to the remote operator and also provides information on the external environment of the vehicle 100, information on the cruising range of the vehicle 100, etc. Note that the information is provided to the remote operator via, for example, an operator terminal that can communicate with the management server 910.

[0073] The remote operator searches for flat candidate stopping locations based on external information about the vehicle 100, information about the cruising range of the vehicle 100, and traffic conditions around the vehicle 100, and transmits information about the searched flat candidate stopping locations to the vehicle control device 500 (microcomputer 510) of the vehicle 100 via the management server 910. Then, upon acquiring the information about the flat candidate stopping locations from the management server 910, the microcomputer 510 (destination setting unit 512) sets the flat candidate stopping locations searched by the remote control center 900 as the destination of the target route along which the vehicle 100 will automatically travel.

[0074] 10 is a flowchart showing the flow of processing in the remote control center 900 for dealing with a failure of the vehicle stop maintenance function of the vehicle 100. The remote control center 900 (management server 910) receives a stop request signal from the vehicle 100 based on the failure of the vehicle stop maintenance function, that is, a signal requesting transmission of information on flat candidate stopping locations (step S911).

[0075] When the management server 910 receives the stop request signal from the vehicle 100, a search for flat candidate stopping locations is carried out by a remote operator at the remote control center 900 (step S912). Then, the management server 910 transmits information on the flat candidate stopping locations searched for by the remote operator to the vehicle control device 500 (microcomputer 510) mounted on the vehicle 100 (step S913).

[0076] 11 is a flowchart showing the flow of processing in the vehicle control device 500 (microcomputer 510) for dealing with a failure of the vehicle stop maintenance function of the vehicle 100. In step S921, the microcomputer 510 acquires diagnostic information of the vehicle 100, including the diagnostic results of the vehicle stop maintenance function.

[0077] Next, in step S922 (vehicle stop maintenance function determination unit 511), microcomputer 510 determines whether or not there is a malfunction in the vehicle stop maintenance function of vehicle 100. If the vehicle stop maintenance function of vehicle 100 is normal, microcomputer 510 ends the processing as is, and if there is a malfunction in the vehicle stop maintenance function of vehicle 100, proceeds to step S923.

[0078] When the microcomputer 510 proceeds to step S923 based on the determination that there is a malfunction in the vehicle stop maintenance function of the vehicle 100, it transmits a stop request signal based on the malfunction of the vehicle stop maintenance function, i.e., a signal requesting the transmission of information on flat candidate stopping locations, to the remote control center 900 (management server 910). Then, in the next step S924 (destination setting unit 512), the microcomputer 510 acquires information on flat candidate stopping locations searched for by the remote operator from the management server 910.

[0079] Next, in step S925 (destination setting unit 512), microcomputer 510 sets the flat candidate stopping location acquired from management server 910 as the destination of the target route along which vehicle 100 will automatically travel. Then, in step S926, microcomputer 510 moves vehicle 100 to the destination and stops it, and in step S927, turns on the hazard lights to notify other vehicles traveling nearby that the vehicle has stopped due to a malfunction.

[0080] In this way, if the vehicle control device 500 (microcomputer 510) acquires information about flat candidate stopping locations searched for by a remote operator at the remote control center 900, the calculation load on the microcomputer 510 is reduced. Furthermore, the candidate stopping location information provided to the vehicle control device 500 from the remote control center 900 is information determined by the remote operator, that is, by a human being, so more accurate candidate stopping location information can be obtained, which may enable the vehicle 100 to stop quickly at an appropriate location.

[0081] The technical ideas described in the above embodiments can be used in appropriate combinations as long as no contradictions arise. Furthermore, although the contents of the present invention have been specifically described with reference to preferred embodiments, it is obvious that a person skilled in the art can adopt various modified embodiments based on the basic technical ideas and teachings of the present invention.

[0082] Vehicles to which the technology for automatically driving and stopping the vehicle to a flat candidate stopping location when the vehicle stop maintenance function fails are assumed to be equipped with an autonomous driving system of level 4 or higher, but it can also be applied to vehicles equipped with an autonomous driving system of level 3 or lower, depending on the conditions. Therefore, the vehicle stop maintenance function is not limited to one that is automatically activated by a control signal from a microcomputer, but may also be one that is activated by driver operation.

[0083] Furthermore, the information about candidate stopping locations that the vehicle control device 500 (microcomputer 510) acquires from outside the vehicle 100 is not limited to information searched by a remote operator, but may also acquire information searched by a computer or AI (Artificial Intelligence) installed outside the vehicle 100. Furthermore, for example, if the vehicle 100 is autonomously traveling on a highway, the vehicle control device 500 (microcomputer 510) can acquire information about available parking spaces in service areas as search information for candidate stopping locations. Furthermore, in the above embodiment, traffic flow and traffic volume are cited as examples of traffic conditions around the vehicle 100 that are used to search for candidate stopping locations. However, the traffic conditions may also be information expressed as traffic density, traffic speed, or the like.

[0084] 100...vehicle, 200...vehicle system, 300...external environment recognition unit, 400...vehicle information detection unit, 500...vehicle control device, 510...microcomputer (control unit), 511...vehicle stop maintenance function determination unit, 512...destination setting unit, 513...vehicle stop possibility re-determination unit, 513A...gradient information acquisition unit, 514...vehicle control unit, 600...traveling actuator unit, 700...vehicle stop maintenance device

Claims

1. A vehicle control device comprising: a parking maintenance function determination unit that determines a failure of a parking maintenance function of a vehicle; a destination setting unit that, when the parking maintenance function is determined to have failed, acquires a flat parking candidate location where the vehicle can park, which is searched based on external information of the vehicle, a remaining travelable distance of the vehicle, and a traffic condition around the vehicle, and sets the flat parking candidate location as a destination of a target route for automatically driving the vehicle; and a vehicle control unit that automatically drives the vehicle to the destination along the target route and parks the vehicle at the destination.

2. The vehicle control device according to claim 1, wherein the destination setting unit acquires the external information from map information.

3. The vehicle control device according to claim 2, wherein the traffic condition includes traffic flow or traffic volume.

4. The vehicle control device according to claim 3, wherein the destination setting unit executes a search for the flat parking candidate location.

5. The vehicle control device according to claim 4, further comprising a parking feasibility re-determination unit that re-determines the feasibility of parking the vehicle at the destination based on external information of the destination and vehicle information including specifications of the vehicle, which are acquired by an external recognition sensor mounted on the vehicle, after the vehicle is automatically driven to the destination; and wherein the destination setting unit re-searches for the flat parking candidate location and newly sets the destination when the parking feasibility re-determination unit determines that parking is not feasible.

6. The vehicle control device according to claim 5, wherein the parking feasibility re-determination unit comprises a gradient information acquisition unit that acquires gradient information of the destination based on the vehicle information including information of sensors provided in the vehicle.

7. The vehicle control device according to claim 4, wherein when the destination setting unit cannot search for the flat parking candidate location, it searches for an inclined parking candidate location where the vehicle can park sideways with respect to the inclination direction based on the map information and the vehicle information including specifications of the vehicle, and sets the inclined parking candidate location as a destination of a target route for automatically driving the vehicle.

8. The vehicle control device according to claim 3, wherein the destination setting unit transmits a parking request signal to a management server provided outside the vehicle when it is determined that the parking maintenance function has failed, and acquires the flat parking candidate area searched based on the parking request signal from the management server.

9. A vehicle control device provided in a vehicle having a parking maintenance device, wherein a control unit included in the vehicle control device searches for a flat parking area based on map information, the vehicle's travelable distance, and the traffic conditions around the vehicle when the parking maintenance device fails, automatically drives the vehicle to the parking area, and parks the vehicle at the parking area.

10. A vehicle control method executed by a control unit included in a vehicle control device mounted on a vehicle, the method comprising: determining a failure of the vehicle's parking maintenance function; when it is determined that the parking maintenance function has failed, acquiring a flat parking candidate area where the vehicle can park, the area being searched based on the vehicle's external information, the vehicle's travelable distance, and the traffic conditions around the vehicle; setting the flat parking candidate area as the destination of a target route for automatically driving the vehicle; automatically driving the vehicle to the destination along the target route; and parking the vehicle at the destination.