Vehicle control method and vehicle control device

Abstract

A controller (30) of a vehicle control device (10) detects another vehicle (91) around a host vehicle (90), detects a relative positional relationship between the host vehicle (90) and the other vehicle (91), calculates a target speed according to a deceleration control request upon acquiring the deceleration control request, the request serving to request to decelerate the vehicle speed of the host vehicle (90) traveling by automatic driving, and gradually changes the deceleration according to the relative positional relationship between the host vehicle (90) and the other vehicle (91) to decelerate the speed of the host vehicle (90) to the target speed.

Description

Vehicle control method and vehicle control device

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

[0002] Conventionally, there is known a device that notifies surrounding vehicles of the behavior of an autonomous vehicle (see, for example, Patent Document 1). The autonomous vehicle of Patent Document 1 is equipped with a rear exterior display device that presents information to other vehicles behind the vehicle. The rear exterior display device displays deceleration during autonomous driving, thereby notifying surrounding vehicles of the behavior of the vehicle.

[0003] Japanese Patent Application Laid-Open No. 2021-108073

[0004] However, in Patent Document 1, when the host vehicle decelerates, the rear exterior display device displays that the host vehicle will decelerate, but it is not possible to inform the vehicle behind of when the deceleration will be implemented or how much deceleration will be implemented. This causes a problem in that the driver of the other vehicle behind the host vehicle cannot grasp the behavior of the host vehicle, which may cause the other vehicle to respond late to the host vehicle.

[0005] An object of the present invention is to provide a vehicle control method and a vehicle control device that can quickly notify surrounding vehicles of the deceleration of the subject vehicle.

[0006] In the present invention, the computer detects the relative positional relationship between the host vehicle and other vehicles around it, and when it acquires a deceleration control request to slow down the vehicle speed of the host vehicle through automatic driving, it calculates a target speed according to the deceleration control request, and when slowing down the vehicle speed to the target speed, it changes the deceleration rate in stages according to the relative positional relationship between the host vehicle and other vehicles.

[0007] This allows the behavior of the host vehicle to quickly notify other vehicles of the host vehicle's deceleration, thereby reducing delays in other vehicles' responses to the host vehicle.

[0008] 1 is a block diagram showing a schematic configuration of a vehicle control device mounted on a vehicle according to an embodiment of the present disclosure; 2 is a diagram showing a schematic configuration of a controller according to the present embodiment and a functional configuration of a processor; 3 is a diagram showing an example of the positional relationship between a host vehicle and another vehicle; 4 is a diagram showing the deceleration and deceleration method of the host vehicle when another vehicle is located behind the host vehicle in a low-speed lane according to the present embodiment; 5 is a diagram showing the deceleration and deceleration method of the host vehicle when another vehicle is located in front of the host vehicle in a low-speed lane according to the present embodiment; 6 is a diagram showing the deceleration and deceleration method of the host vehicle when another vehicle is located in an overtaking lane according to the present embodiment;

[0009] An embodiment of the present disclosure will be described below. Fig. 1 is a block diagram showing a schematic configuration of a vehicle control device 10 mounted on a vehicle (host vehicle) according to this embodiment. The vehicle control device 10 mounted on the vehicle according to this embodiment includes a communication unit 11, a sensor group 12, a vehicle drive mechanism 20, and a controller 30. In this embodiment, an autonomous vehicle that performs autonomous driving by controlling the vehicle drive mechanism 20 under the control of the controller 30 is exemplified as the vehicle.

[0010] The communication unit 11 receives various information from a predetermined external device 40 via a predetermined wireless communication line such as the Internet line. The information received from the external device 40 includes, for example, road traffic information related to congested sections on roads.

[0011] The sensor group 12 measures various sensor information related to the traveling of the host vehicle. The sensor group 12 includes a position detection sensor 121, a surroundings detection sensor 122, an imaging camera 123, a speed sensor 124, and the like. The position detection sensor 121 may be, for example, a receiver that receives satellite signals from a Global Navigation Satellite System (GNSS) to determine the current position, and detects the current position of the host vehicle. The surroundings detection sensor 122 detects surrounding objects. The surroundings detection sensor 122 may use various types of sensors, such as laser radar, millimeter-wave radar, and ultrasonic radar, and a combination of these may also be used. The imaging camera 123 captures images of the surroundings of the host vehicle to obtain captured images. The speed sensor 124 measures the wheel speed of the host vehicle. Note that, although the position detection sensor 121, the surroundings detection sensor 122, the imaging camera 123, and the speed sensor 124 are exemplified as the sensor group 12, sensors that detect other information may also be provided. For example, an acceleration sensor for measuring acceleration, a yaw rate sensor for detecting the yaw rate of the host vehicle, and the like may be further provided.

[0012] The vehicle drive mechanism 20 has an engine actuator 21, a brake hydraulic actuator 22, and a steering angle actuator 23. The engine actuator 21 is an actuator that controls the engine drive force by receiving a drive control command value based on a target speed from the controller 30. In the case of a hybrid vehicle, an engine actuator and a motor actuator may be used, and in the case of an electric vehicle, a motor actuator may be used.

[0013] The brake hydraulic actuator 22 controls the brake hydraulic braking force by receiving a braking control command value based on the target speed from the controller 30. Note that in the case of an electric vehicle not equipped with a hydraulic booster, an electric booster may be used. The steering angle actuator 23 is a steering angle control motor that controls the steering angle of the steered wheels by receiving a steering angle control command value from the controller 30.

[0014] 2 is a diagram showing a schematic configuration of the controller 30 according to this embodiment and a functional configuration of the processor 32. The controller 30 controls the autonomous driving of the host vehicle. The controller 30 is a computer including a memory 31 as a recording device for recording various information, and a processor 32 including an arithmetic circuit such as a CPU (Central Processing Unit).

[0015] The memory 31 stores various types of information and programs for controlling the autonomous driving of the vehicle. An example of the various types of information stored in the memory 31 is map information. The map information is information in which latitude and longitude are associated with points on a map. The map information includes road information defined by nodes and links connecting the nodes. The road information may be stored in association with various types of information such as the road width and number of lanes of the road, priority relative to intersecting roads, and speed limits. Furthermore, the nodes or links included in the road information may include traffic light information related to traffic lights installed at intersections, for example.

[0016] The map information recorded in the memory 31 may be only a map within a predetermined distance range centered on the current location of the vehicle, or only a map within a predetermined distance range centered on the route from the current location of the vehicle to the destination. In this case, new map information may be downloaded from the external device 40 as needed depending on the current location of the vehicle. Furthermore, the map information recorded in the memory 31 may be updated by periodically downloading map information from the external device 40.

[0017] 2, the processor 32 functions as a vehicle position detection unit 321, a route acquisition unit 322, a surrounding condition detection unit 323, a traffic jam section detection unit 324, a deceleration section setting unit 325, a target speed setting unit 326, a relative relationship detection unit 327, a deceleration setting unit 328, a vehicle control unit 329, etc. Note that, here, an example is shown in which the processor 32 executes a program to realize the respective functional configurations of the vehicle position detection unit 321, the route acquisition unit 322, the surrounding condition detection unit 323, the traffic jam section detection unit 324, the deceleration section setting unit 325, the target speed setting unit 326, the relative relationship detection unit 327, the deceleration setting unit 328, and the vehicle control unit 329, but some or all of these may be realized by individual hardware configurations.

[0018] The vehicle position detection unit 321 detects the position of the vehicle based on a sensor signal input from the position detection sensor 121. Furthermore, the vehicle position detection unit 321 detects the position of the lane in which the vehicle is traveling (the vehicle's own lane) on the road on which the vehicle is traveling based on an image captured by the imaging camera 123.

[0019] The route acquisition unit 322 acquires a driving route for the vehicle. Specifically, the route acquisition unit 322 acquires a destination input by a user (e.g., the driver of the vehicle). Then, based on the input purpose and the current position of the vehicle detected by the vehicle position detection unit 321, the route acquisition unit 322 calculates a driving route from the current position on a map to the destination. Note that the driving route may be set by a navigation device, and the driving route may be acquired from the navigation device. The navigation device may be a navigation device mounted on the vehicle, or may be a mobile terminal such as a smartphone connected to the vehicle control device 10 so as to be able to communicate with the vehicle control device 10.

[0020] The surrounding situation detection unit 323 detects objects around the host vehicle based on the sensor signal input from the surrounding detection sensor 122. In this embodiment, other vehicles around the host vehicle are detected as the surrounding objects.

[0021] The congested section detection unit 324 detects congested sections on the travel route based on road traffic information acquired from the external device 40 via the communication unit 11. Examples of road traffic information include traffic congestion information received from VICS (registered trademark) or a map server that provides a predetermined map guidance service. When map information is received from the external device 40, the traffic congestion information may be received together with the map information.

[0022] The deceleration zone setting unit 325 sets a deceleration zone for the host vehicle on the travel route. For example, in this embodiment, when a congested zone is detected on the travel route, the deceleration zone setting unit 325 delays the host vehicle's arrival at the congested zone so that the host vehicle does not enter the congested zone, thereby alleviating congestion in the congested zone. Therefore, when a congested zone is detected, the deceleration zone setting unit 325 sets a deceleration zone on the travel route between the host vehicle's current position and the congested zone. The deceleration zone can be set based on, for example, the time the vehicle stops at each traffic light on the travel route (signal stop time). Examples of the signal stop time include the time the traffic light remains red, the average or maximum stop time at each traffic light based on the travel history of the host vehicle and other vehicles, and the time duty ratio of the time the traffic light remains red relative to the time it takes for the traffic light to change color. Then, for example, the deceleration zone is set from a traffic light where the signal stop time is equal to or less than a predetermined value to the next traffic light.

[0023] When the target speed setting unit 326 receives a deceleration control request to decelerate the speed of the host vehicle traveling in an autonomous driving mode, the target speed setting unit 326 sets a target speed in accordance with the deceleration control request. In this embodiment, the "deceleration control request" refers to the setting of a deceleration section by the deceleration section setting unit 325. The "target speed in accordance with the deceleration control request" refers to the speed at which the host vehicle will arrive at the congested section after the congestion resolution time in the congested section when traveling through the deceleration section at the set target speed. Therefore, when the deceleration section setting unit 325 sets a deceleration section, the target speed setting unit 326 sets a target speed for the deceleration section. For example, the target speed setting unit 326 sets a smaller target speed based on the stop time of the traffic light that is the starting point of each deceleration section, the shorter the traffic light stop time. To do this, the target speed setting unit 326 calculates a tentative arrival time for traveling from the current position of the host vehicle to the congested section at a normal speed (e.g., the legal speed limit) and a predicted time for congestion resolution in the congested section, and calculates the difference between the two values ​​as the required delay time. Furthermore, the required delay time is allocated to each deceleration section according to the traffic light stop time, and this is set as the target delay time for each deceleration section.The target travel time for the deceleration section is then calculated by subtracting the target delay time from the time it would take to travel through the deceleration section at a normal speed, and the target speed for the deceleration section is calculated based on the target travel time and the section distance of the deceleration section.Note that this disclosure illustrates, as an example, an example in which a deceleration section is set when a congested section is detected, and a target speed for the deceleration section that is slower than the normal speed is calculated, but this is not limiting.If deceleration processing is required during autonomous driving, the target speed for the deceleration processing may be calculated as appropriate.

[0024] The relative relationship detection unit 327 detects the relative positional relationship between the host vehicle and other surrounding vehicles detected by the surrounding situation detection unit 323. The relative positional relationship in the present disclosure includes not only the relative positions between the host vehicle and other vehicles but also the relative speeds between the host vehicle and other vehicles.

[0025] The deceleration setting unit 328 functions as a deceleration control unit together with the vehicle control unit 329, and sets the deceleration and deceleration method in the deceleration section. Fig. 3 is a diagram showing an example of the positional relationship between the host vehicle and other vehicles. In Fig. 3, the lane adjacent to the right of the lane in which the host vehicle 90 is traveling (host lane 80) is set as an overtaking lane 81 in which vehicles traveling faster than the host vehicle 90 are likely to travel. The adjacent lane adjacent to the left of the host lane 80 is set as a low-speed lane 82 in which vehicles traveling slower than the host vehicle 90 are likely to travel.

[0026] 4 is a diagram showing the deceleration and deceleration method of the host vehicle 90 when another vehicle 91 is located behind the host vehicle 90 in the low-speed lane 82. When another vehicle 91 is located to the left rear A1, the deceleration setting unit 328 sets the deceleration and deceleration method so that the speed of the host vehicle is reduced to the target speed by changing the deceleration in stages, as shown in FIG. ０ a first deceleration R １ After a predetermined time has elapsed, the vehicle decelerates at a first deceleration rate R １ a second deceleration R ２ The normal deceleration R ０ For example, the deceleration during deceleration in general automatic driving is 0.1 G (1 G ≒ 9.8 m / s ２ ). In this way, the initial first deceleration R １ By significantly reducing the vehicle speed through deceleration, it is possible to clearly communicate to the driver of the other vehicle 91 the intention to decelerate the vehicle 90 .

[0027] Here, the deceleration setting unit 328 sets the first deceleration R as the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 increases, compared to when the inter-vehicle distance is short. １ Alternatively, the deceleration setting unit 328 sets the first deceleration R to be larger as the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 increases compared to when the inter-vehicle distance is short. １ the period during which the deceleration is performed (first deceleration period T １ Alternatively, the deceleration setting unit 328 may set the first deceleration R 1 to be longer as the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 increases compared to when the inter-vehicle distance is short.１ and the first deceleration period T １ By reducing the deceleration as the inter-vehicle distance becomes shorter, it is possible to prevent the driver of the other vehicle 91 from paying attention to the host vehicle 90 for an unnecessary increase in the time. ２ is, for example, the first deceleration R １ The deceleration may be a predetermined ratio (for example, half) of the second deceleration R, or may be a normal deceleration (0.1 G). ２ (second deceleration period T ２ ) is the speed of the host vehicle 90 before deceleration, the target speed, and the first deceleration R １ , second deceleration R ２ , and the first deceleration period T １ It is calculated appropriately by

[0028] 5 is a diagram showing the deceleration and deceleration method of the host vehicle 90 when another vehicle 91 is located ahead of the host vehicle 90 in the low-speed lane 82. In FIG. 5, the solid line indicates the deceleration when the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 is a predetermined first distance, and the dashed line indicates the deceleration when the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 is a second distance that is closer than the first distance. When the other vehicle 91 is located ahead and to the left A2, the deceleration setting unit 328 sets the normal deceleration R ０ In this case, the deceleration setting unit 328 sets a deceleration smaller than the deceleration R when the inter-vehicle distance between the subject vehicle 90 and the other vehicle 91 is greater than when the inter-vehicle distance is short. For example, when the inter-vehicle distance between the subject vehicle 90 and the other vehicle 91 is a predetermined first distance, the deceleration setting unit 328 sets a deceleration smaller than the deceleration R ３ is set, and when the inter-vehicle distance is a second distance that is closer (smaller) than the first distance, the deceleration R ４ is set. In this way, by reducing the deceleration as the inter-vehicle distance becomes shorter, it is possible to prevent the driver of the other vehicle 91 from paying attention to the host vehicle 90 for an unnecessary increase in the amount of time. Note that an upper limit value for the deceleration to be set is set in advance, and when the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 is equal to or greater than a predetermined distance threshold, the deceleration setting unit 328 sets the upper limit value to the deceleration.

[0029] 6 is a diagram showing the deceleration and deceleration method of the host vehicle 90 when another vehicle 91 is located in the passing lane 81. In FIG. 6, the solid line indicates the deceleration when the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 is equal to or greater than a predetermined distance threshold, and the dashed line indicates the deceleration when the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 is less than the distance threshold. When the other vehicle 91 is traveling in the passing lane, the speed of the other vehicle 91 is generally faster than the speed of the host vehicle 90, and the relative speed becomes large. In this case, the normal deceleration R ０ Therefore, when changing lanes into the own vehicle 90, the other vehicle 91 traveling in the overtaking lane 81 can determine whether to change lanes ahead of the own vehicle 90 or behind the own vehicle 90 as usual.

[0030] For this reason, in this embodiment, when the other vehicle 91 is traveling in the passing lane 81, the deceleration setting unit 328 sets the same deceleration regardless of whether the other vehicle 91 is located in front or behind the host vehicle 90. In other words, when the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 is equal to or greater than a predetermined distance threshold, the deceleration setting unit 328 sets a normal deceleration.

[0031] On the other hand, when the inter-vehicle distance between the subject vehicle 90 and the other vehicle 91 is less than the distance threshold, the deceleration setting unit 328 increases the deceleration as the inter-vehicle distance between the subject vehicle 90 and the other vehicle 91 increases, compared to when the inter-vehicle distance is short. This makes it possible to prevent an unnecessary increase in the amount of time the driver of the other vehicle 91 pays attention to the subject vehicle 90 when the inter-vehicle distance between the subject vehicle 90 and the other vehicle 91 is short.

[0032] The vehicle control unit 329 outputs a control command related to automatic driving to the vehicle drive mechanism 20 based on the target speed set by the target speed setting unit 326 and the deceleration and deceleration method set by the deceleration setting unit 328. As a result, the engine actuator 21, brake hydraulic actuator 22, and steering angle actuator 23 of the vehicle drive mechanism 20 cause the host vehicle to travel at the legal speed in deceleration prohibited sections and at the set target speed in deceleration sections. When decelerating the host vehicle in a deceleration section, as described above, the host vehicle is decelerated by the deceleration and deceleration method set in accordance with the relative positional relationship between the host vehicle 90 and the other vehicle 91.

[0033] [Configuration of External Device 40] The external device 40 is a computer capable of communicating with vehicles equipped with the vehicle control device 10 via, for example, an Internet line, and transmits various information to each vehicle. Specifically, the external device 40 transmits map information, road traffic information, traffic light information (traffic light stop times), etc. in response to requests from each vehicle. Note that while FIG. 1 illustrates a single external device 40, the external device 40 may be divided into multiple devices depending on, for example, the distribution area or the content of the information to be transmitted. For example, the external device 40 may include a map distribution device that transmits map information, a traffic information distribution device that transmits road traffic information, and a traffic light information distribution device that transmits traffic light information, each of which is independently provided. Furthermore, these external devices 40 may be configured as a cloud server constructed by connecting multiple computers via a network. Note that in this embodiment, a configuration in which a single external device 40 distributes map information, road traffic information, and traffic light information will be described as an example.

[0034] The external device 40 does not need to distribute all of the map information, road traffic information, and traffic light information, but only needs to distribute corresponding information in response to a request signal from the vehicle as needed. For example, if map information is stored in the memory 31 installed in the vehicle, the external device 40 does not need to distribute the map information, and only needs to distribute the map information when, for example, a map update request is received from the vehicle. The same applies to traffic light information; if traffic light information is associated with map information in the vehicle's memory 31 or if traffic light stop times are calculated based on road categories, there is no need to distribute the traffic light information. If map information is stored in the memory 31 of each vehicle and distribution of traffic light information is not necessary, the external device 40 only needs to distribute at least road traffic information related to congestion on the road.

[0035] [Vehicle Control Method] Next, the vehicle control method of this embodiment will be described. Figures 7 and 8 are flowcharts showing the vehicle control method of this embodiment. In this embodiment, when a destination is input by a user operation and a command is input requesting a search for a travel route from the current position of the vehicle to the destination, the route acquisition unit 322 acquires (searches for) a travel route from the current position of the vehicle detected by the position detection sensor 121 to the destination based on map information (step S1).

[0036] Furthermore, when a command requesting autonomous driving of the host vehicle is input by user operation, the vehicle control unit 329 outputs a control command to the vehicle drive mechanism 20 to drive the host vehicle along the driving route, and starts autonomous driving of the host vehicle (step S2). Once autonomous driving is started in step S2, detection processing of various information is continuously performed thereafter by the sensor group 12. As a result, the host vehicle position detection unit 321 continuously (at a predetermined interval) detects the current position of the host vehicle 90 and the position of the host lane 80 in which the host vehicle 90 is traveling, and the surrounding condition detection unit 323 detects obstacles around the host vehicle 90 and other vehicles 91 traveling in the vicinity.

[0037] In this autonomous driving process, the congested section detection unit 324 detects a congested section occurring ahead of the vehicle on the driving route (step S3). Specifically, the congested section detection unit 324 transmits the current position of the vehicle and the driving route to the external device 40, and requests the congested section on the driving route. In this way, the congested section detection unit 324 acquires the congested section on the driving route from the external device 40. The congested section includes the position of the starting point of the congested section and the length of the congested section.

[0038] Next, the congested section detection unit 324 determines whether there is a congested section on the travel route (step S4). If the determination in step S4 is NO, the target speed is not set taking congestion into consideration, but is set as a normal target speed (step S5). In other words, the target speed setting unit 326 sets the target speed on the travel route to a speed that complies with standards and manners, based on the legal speed limit for the road on which the vehicle is traveling, or the speeds of vehicles ahead of the vehicle and other vehicles around the vehicle.

[0039] On the other hand, if the determination in step S4 is YES, the deceleration section setting unit 325 sets a deceleration section between the current position of the vehicle 90 and the congestion section (step S6). As described above, the deceleration section is set based on, for example, the stop time of traffic lights that exist between the vehicle 90 and the congestion section, and the section from the traffic light where the stop time is less than a predetermined time to the next traffic light in the direction of travel is set as the deceleration section.

[0040] Next, the target speed setting unit 326 sets target speeds for the deceleration sections and other sections on the travel route (step S7). In step S7, the target speed setting unit 326 sets, for example, the legal speed as the target speed for sections other than the deceleration sections. Furthermore, the target speed setting unit 326 calculates the target speed for each deceleration section based on the stop time of the traffic light that is the starting point of the deceleration section. The target speed is set, for example, for each deceleration section so that the vehicle will arrive at the congested section by the time the congestion clears if it travels through the deceleration section and sections other than the deceleration section at the set target speed. In this case, the target speed setting unit 326 calculates a tentative arrival time for traveling from the current location to the congested section at the legal speed, and sets the target speed for the deceleration section based on the difference between the tentative arrival time and the time it takes for the congestion in the congested section to clear.

[0041] After this, the vehicle control unit 329 outputs a control command related to automatic driving to the vehicle drive mechanism 20 based on the target speed set in step S5 or the target speed set in step S7, and controls the speed of the vehicle during automatic driving in each section (step S8).

[0042] 8 is a flowchart showing a driving control method during automatic driving in step S8. In the automatic driving control in step S8, it is determined whether the current position of the host vehicle 90 detected by the host vehicle position detection unit 321 has reached a deceleration zone (step S9). If the determination in step S9 is YES, the relative relationship detection unit 327 detects the relative positional relationship between the host vehicle 90 and another vehicle 91 detected by the surrounding situation detection unit 323 (step S10). That is, the relative position, relative speed, and inter-vehicle distance between the host vehicle 90 and the other vehicle 91 are calculated. If the determination in step S9 is NO, automatic driving is continued and the process returns to step S9.

[0043] After step S10, the deceleration setting unit 328 determines whether the congestion section detected in step S3 is in a congestion state in which the host vehicle 90 is congested in the lane 80 but the adjacent lanes (the overtaking lane 81 and the slow lane 82) are not congested (step S11). That is, the vehicle control device 10 of this embodiment sets the deceleration and deceleration method based on the relative positional relationship between the host vehicle 90 and the other vehicle 91 when congestion occurs in the host vehicle lane 80 but not in the adjacent lanes (the overtaking lane 81 and the slow lane 82). The situation in which "congestion occurs in the host vehicle lane 80 but not in the adjacent lanes (the overtaking lane 81 and the slow lane 82)" includes a situation in which congestion occurs only in the host vehicle lane 80 in the congestion section, a situation in which congestion occurs between the host vehicle 80 and the overtaking lane 81 but not in the slow lane 82, and a situation in which congestion occurs between the host vehicle 80 and the slow lane 82 but not in the overtaking lane 81. If the determination in step S11 is NO, the deceleration setting unit 328 sets a normal deceleration (step S12). In other words, if the determination in step S11 is NO, congestion has occurred in all lanes, and in this case, vehicles in each lane decelerate uniformly, so there is no need to perform stepwise deceleration processing.

[0044] If the determination in step S11 is YES, the deceleration setting unit 328 executes the stepwise deceleration process of the present disclosure. That is, the deceleration setting unit 328 sets the deceleration and the deceleration method when decelerating in the deceleration section based on the relative positional relationship between the host vehicle 90 and the other vehicle 91 (step S13).

[0045] 3 to 6, the deceleration setting unit 328 sets a deceleration method in which the deceleration is changed in stages when the other vehicle 91 is located to the left rear A1 of the host vehicle 90. At this time, the deceleration method is set in accordance with the distance between the host vehicle 90 and the other vehicle 91. The greater the distance between the vehicles, the greater the first deceleration R １ or the first deceleration period T １ or the first deceleration R １ is increased, and the first deceleration period T １Furthermore, when the other vehicle 91 is located to the left front A2, right rear A3, or right front A4 of the host vehicle 90, the deceleration setting unit 328 does not set a stepwise change in deceleration, but decelerates the host vehicle 90 to the target speed at a predetermined deceleration. For example, when the other vehicle 91 is located to the left front A2 of the host vehicle 90 and the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 is equal to or greater than a predetermined distance threshold, the normal deceleration R ０ An upper limit value smaller than the above is set for the deceleration. When the other vehicle 91 is to the left front A2 of the host vehicle 90 and the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 is less than the distance threshold, a deceleration is set that decreases as the inter-vehicle distance becomes shorter. When the other vehicle 91 is to the right rear A3 or right front A4 of the host vehicle 90 and the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 is equal to or greater than a predetermined distance threshold, a normal deceleration is set for the deceleration. When the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 is less than the distance threshold, a deceleration is set that decreases as the inter-vehicle distance becomes shorter.

[0046] If there are multiple other vehicles 91 around the host vehicle 90, the deceleration setting unit 328 prioritizes the other vehicle 91 on the left rear A1, and if there are multiple other vehicles 91 on the left rear A1, prioritizes the other vehicle 91 with the closest inter-vehicle distance, and sets the deceleration and deceleration method. If there is no other vehicle 91 on the left rear A1, prioritizes the other vehicle 91 on the left front A2, and if there are multiple other vehicles 91 on the left front A2, prioritizes the other vehicle 91 with the closest inter-vehicle distance, and sets the deceleration and deceleration method.

[0047] When the deceleration rate and deceleration method are set in step S12 or step S13, the vehicle control unit 329 outputs a control command based on the set deceleration rate and deceleration method to the vehicle drive mechanism 20, and performs deceleration processing of the host vehicle in the deceleration section (step S14). As a result, in this embodiment, when another vehicle 91 is present to the left rear A1 of the host vehicle 90, a step-by-step deceleration processing is performed in which the deceleration rate is changed in steps to decelerate the host vehicle 90. At other positions, the step-by-step deceleration processing is not performed, but the closer the inter-vehicle distance, the smaller (more gradual) deceleration is performed.

[0048] After step S14, the automatic driving continues, and the process returns to step S9. When the host vehicle 90 leaves the deceleration section and the target speed is increased, the vehicle control unit 329 increases the speed of the host vehicle in accordance with the set target speed and continues the automatic driving. When the host vehicle 90 enters a deceleration section with a lower target speed, a YES determination is made again in step S9, and the deceleration control of steps S10 to S14 is performed.

[0049] [Effects of the Present Embodiment] In the vehicle control device 10 of the present embodiment, the processor 32 of the controller 30 reads and executes a program recorded in the memory 31, thereby functioning as a relative relationship detection unit 327, a deceleration zone setting unit 325, a target speed setting unit 326, a deceleration setting unit 328, and a vehicle control unit 329. The controller 30 detects the relative positional relationship between the host vehicle 90 and a surrounding other vehicle 91 using the relative relationship detection unit 327, and when a deceleration zone is set by the deceleration zone setting unit 325, sets a target speed for the deceleration zone using the target speed setting unit 326. The controller 30 then performs a stepwise deceleration process using the deceleration setting unit 328 and the vehicle control unit 329 to gradually change the deceleration in accordance with the relative positional relationship between the host vehicle 90 and the other vehicle 91, thereby decelerating the speed of the host vehicle 90 to the target speed. For example, in the present embodiment, the stepwise deceleration process is performed when the other vehicle 91 is located to the left rear A1 of the host vehicle 90. By performing such a stepwise deceleration process, the driver of the other vehicle 91 can pay close attention to the behavior of the host vehicle 90, and can communicate the intention to decelerate the host vehicle 90. In other words, for example, when the deceleration of the host vehicle is communicated using an external display device, it is difficult to communicate to the driver of the other vehicle 91 the extent of deceleration and the timing at which the deceleration will occur. In contrast, in this embodiment, the deceleration of the host vehicle 90 is communicated to the driver of the other vehicle 91 based on the behavior of the host vehicle 90, so both the timing and the degree of deceleration can be clearly communicated to the other vehicle 91. This allows the driver of the other vehicle 91 to quickly respond to the host vehicle 90.

[0050] In the present embodiment, the deceleration setting unit 328 sets a deceleration method and a deceleration that change the deceleration in stages when another vehicle 91 is located behind the host vehicle 90 in the low-speed lane 82 adjacent to the host vehicle lane 80, and the vehicle control unit 329 decelerates the speed of the host vehicle to a target speed according to the set deceleration and deceleration method. The other vehicle 91 traveling in the low-speed lane 82 adjacent to the host vehicle 90 is generally slower than the host vehicle 90, and if the other vehicle 91 wishes to change lanes into the host vehicle 90 traveling in the same lane 80, it needs to determine whether to change lanes behind the host vehicle 90 or to accelerate to a position in front of the host vehicle 90 and change lanes. In the present embodiment, the deceleration of the host vehicle 90 is performed by changing the deceleration in stages, so that the driver of the other vehicle 91 can understand the deceleration of the host vehicle 90 from the behavior of the host vehicle 90. Therefore, when changing lanes toward the own vehicle 90, the driver of the other vehicle 91 can quickly determine whether to change lanes ahead of the own vehicle 90 or behind the own vehicle 90.

[0051] In this embodiment, when the other vehicle 91 is located ahead of the host vehicle 90 in its own lane, the deceleration setting unit 328 does not set a stepwise deceleration, and the vehicle control unit 329 decelerates the host vehicle 90 to the target speed at a single deceleration. When the host vehicle 90 decelerates, if the other vehicle 91 traveling ahead of the host vehicle 90 changes lanes into the host vehicle 90's own lane 80, the other vehicle 91 generally changes lanes ahead of the host vehicle 90. Here, if the host vehicle 90 exhibits a behavior of changing the deceleration stepwise, the other vehicle 91 may spend an increased amount of time gazing at the host vehicle 90, which may delay the other vehicle 91's response to the host vehicle 90. In this embodiment, as described above, when the other vehicle 91 is located ahead of the host vehicle 90, changing the stepwise deceleration is prohibited. This makes it possible to prevent the other vehicle 91 traveling ahead of the host vehicle 90 from spending an unnecessary amount of time gazing at the host vehicle 90.

[0052] In this embodiment, the deceleration setting unit 328 sets the first deceleration (first deceleration) to be greater than the second deceleration (second deceleration) when another vehicle 91 is located behind the host vehicle 90 in the low-speed lane 82 adjacent to the host vehicle lane 80. This makes it possible to more clearly communicate the deceleration of the host vehicle 90 to the driver of the other vehicle 91 in the initial deceleration behavior of the host vehicle 90.

[0053] In the present embodiment, when another vehicle 91 is located behind the host vehicle 90 in the low-speed lane 82 adjacent to the host vehicle lane 80, the deceleration setting unit 328 increases the first deceleration as the distance between the host vehicle 90 and the other vehicle 91 increases. This allows the driver of the other vehicle 91 to more quickly understand the deceleration of the host vehicle 90 from the behavior of the host vehicle 90. Furthermore, when the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 is short, the other vehicle 91 spends a long time paying attention to the movement of the host vehicle 90, and the longer the inter-vehicle distance between the host vehicle 90 and the other vehicle 91, the shorter the time the other vehicle 91 spends paying attention to the movement of the host vehicle 90. In the present embodiment, by decreasing the deceleration as the inter-vehicle distance between the host vehicle 90 and the other vehicle 91 decreases, an unnecessary increase in the time the other vehicle 91, which is close to the host vehicle 90, spends paying attention to the host vehicle 90 can be suppressed.

[0054] In this embodiment, when another vehicle 91 is located behind the host vehicle 90 in the low-speed lane 82 adjacent to the host vehicle lane 80, the deceleration setting unit 328 may set the duration of deceleration at the first deceleration to be longer the greater the distance between the host vehicle 90 and the other vehicle 91. Even in this case, it is possible to suppress an unnecessary increase in the time that the other vehicle 91, which is close to the host vehicle 90, pays attention to the host vehicle 90.

[0055] In addition, in this embodiment, when the host vehicle 90 and at least one adjacent lane (the overtaking lane 81 or the low-speed lane 82) exist, and congestion is detected in the host vehicle 80 but not in the adjacent lane, the deceleration and deceleration method are set according to the relative positional relationship between the host vehicle 90 and the other vehicle 91. The deceleration process by the vehicle control device 10 of this embodiment functions particularly effectively in a situation where congestion occurs in the host vehicle 90 but not in the lane adjacent to the host vehicle 90. In other words, when congestion occurs ahead of the host vehicle 90 in the host vehicle 80, the host vehicle 90 traveling in the host vehicle 90 decelerates to alleviate the congestion. On the other hand, when there is no congestion in the adjacent lane, the other vehicle 91 is likely to continue traveling at a normal speed. Under such circumstances, when the other vehicle 91 in the adjacent lane changes lanes into the host vehicle 90 traveling in the host vehicle 90, it is necessary to more quickly grasp the behavior of the host vehicle 90. In this embodiment, under the above-described circumstances, the behavior of the subject vehicle 90 can quickly convey the deceleration of the subject vehicle 90 to the other vehicle 91, thereby effectively assisting the other vehicle 91 in responding to the subject vehicle 90.

[0056] [Modifications] The present invention is not limited to the above-described embodiment, and includes the following modifications within the scope of achieving the object of the present invention.

[0057] In the above embodiment, the lane adjacent to the host vehicle 90 on the right side is the overtaking lane 81, the lane adjacent to the host vehicle 90 on the left side is the low-speed lane 82, and when another vehicle 91 is present to the left rear A1 of the host vehicle 90, the deceleration is changed in stages to reduce the vehicle speed to the target speed. In contrast, when the left side of the host vehicle 90 is the overtaking lane 81 and the right side is the low-speed lane 82, when another vehicle 91 is present to the right rear of the host vehicle 90, the deceleration is changed in stages to reduce the vehicle speed to the target speed.

[0058] [Modification 2] In the above embodiment, an example was described in which the deceleration setting unit 328 sets the deceleration and deceleration method when decelerating the host vehicle 90 in accordance with the relative position of the other vehicle 91 with respect to the host vehicle 90. In contrast, the relative positional relationship in the present disclosure includes not only the relative positions of the host vehicle 90 and the other vehicle 91 but also the relative speed between the host vehicle 90 and the other vehicle 91, and the deceleration setting unit 328 may set the deceleration and deceleration method when decelerating the host vehicle 90 in accordance with the relative speed between the host vehicle 90 and the other vehicle 91. For example, when the other vehicle 91 is traveling in the passing lane 81, the other vehicle 91 is likely to be traveling faster than the host vehicle 90, and the relative speed between the host vehicle 90 and the other vehicle 91 is also high. When the relative speed is high, as described above, even if the deceleration of the host vehicle 90 is small, the deceleration of the host vehicle 90 is easily conveyed to the driver of the other vehicle 91. Therefore, for example, when the relative speed is greater than a predetermined value and the inter-vehicle distance between the subject vehicle 90 and the other vehicle 91 is equal to or greater than a predetermined distance threshold, a normal deceleration is set. Also, when the inter-vehicle distance between the subject vehicle 90 and the other vehicle 91 is less than the distance threshold, the deceleration is decreased as the inter-vehicle distance between the subject vehicle 90 and the other vehicle 91 becomes shorter.

[0059] On the other hand, when the relative speed between the host vehicle 90 and the other vehicle 91 is lower than a predetermined value and the other vehicle 91 is located behind the host vehicle 90, the deceleration is changed in stages, and the host vehicle 90 is decelerated at a first deceleration and then at a second deceleration which is lower than the first deceleration. Furthermore, the greater the distance between the host vehicle 90 and the other vehicle 91, the greater the first deceleration, or the longer the deceleration period at the first deceleration. Furthermore, when the relative speed between the host vehicle 90 and the other vehicle 91 is lower than a predetermined value and the other vehicle 91 is located ahead of the host vehicle 90, if the distance between the host vehicle 90 and the other vehicle 91 is greater than a predetermined distance threshold, a normal deceleration is set. In this case, if the distance between the host vehicle 90 and the other vehicle 91 is less than the distance threshold, the closer the distance between the host vehicle 90 and the other vehicle 91, the smaller the deceleration.

[0060] [Modification 3] In the above embodiment, an example has been shown in which a deceleration rate that is lower than the normal deceleration rate is set when the other vehicle 91 is located to the left front A2 of the host vehicle 90. However, this is not limiting. For example, when the other vehicle 91 is located to the left front A2 of the host vehicle 90, the vehicle control device 10 may decelerate the host vehicle 90 at the normal deceleration rate, similar to when the other vehicle 91 is located on the passing lane 81 side.

[0061] [Modification 4] In the above embodiment, the vehicle speed is decelerated to the target speed by stepwise deceleration only when the other vehicle 91 is located to the left rear A1 of the host vehicle 90. However, this is not limited to this. For example, when the other vehicle 91 is traveling in the low-speed lane 82, the vehicle control device 10 may perform stepwise deceleration processing to decelerate the other vehicle 91 to the target speed by changing the deceleration rate stepwise, regardless of whether the other vehicle 91 is in front of or behind the host vehicle 90.

[0062] Alternatively, when another vehicle 91 is traveling behind the vehicle 90, the vehicle control device 10 may perform a gradual deceleration process in which the deceleration rate is gradually changed to decelerate to the target speed, regardless of whether the lane in which the other vehicle 91 is traveling is the overtaking lane 81 or the low-speed lane 82.

[0063] [Variation 5] In the above embodiment, when it is determined in step S11 that there is congestion ahead in the own vehicle lane 80 but not in the adjacent lane, the deceleration setting unit 328 sets the deceleration and deceleration method based on the relative positional relationship between the own vehicle 90 and the other vehicle 91 in step S13. However, this is not limiting. For example, the deceleration and deceleration method based on the relative positional relationship in step S13 may be set regardless of whether the own vehicle 90 is the only vehicle in the congestion section.

[0064] [Variation 6] In the above embodiment, when another vehicle 91 is located to the left rear A1 of the vehicle 90, an example is shown in which the deceleration rate is switched between two stages to decelerate to the target speed, but deceleration may also be performed by switching between three or more stages of deceleration.

[0065] [Variation 7] In the above embodiment, as an example, the detection of a congested section and the setting of a deceleration section are considered to be a "deceleration control request," and a target speed in the congested section is set as a target speed corresponding to the deceleration control request. However, this is not limited to this. As described above, a deceleration control request may be output as needed when deceleration processing is required during autonomous driving. For example, the surrounding condition detection unit 323 may output a deceleration control request by detecting another vehicle cutting in front of the host vehicle 90, an emergency vehicle, or the like. In this case, the target speed setting unit 326 may immediately generate a target speed that is slower than the current speed in response to the deceleration control request. As a result, the deceleration setting unit 328 sets a deceleration rate and a deceleration method according to the relative positional relationship detected by the relative relationship detection unit 327, and the vehicle control unit 329 immediately decelerates the vehicle to the target speed using the set deceleration rate and deceleration method.

[0066] 10...vehicle control device, 30...controller (computer), 80...own lane, 81...overtaking lane, 82...low speed lane, 90...own vehicle, 91...other vehicle, 321...own vehicle position detection unit, 322...route acquisition unit, 323...surrounding condition detection unit, 324...congestion section detection unit, 325...deceleration section setting unit, 326...target speed setting unit, 327...relative relationship detection unit, 328...deceleration setting unit, 329...vehicle control unit.

Claims

1. A vehicle control method for controlling a host vehicle by a computer, wherein the computer detects other vehicles around the host vehicle to detect a relative positional relationship between the host vehicle and the other vehicles, and when a deceleration control request to decelerate the speed of the host vehicle traveling by autonomous driving is acquired, calculates a target speed according to the deceleration control request, and performs a step-by-step deceleration process to decelerate the speed of the host vehicle to the target speed by gradually changing the deceleration according to the relative positional relationship between the host vehicle and the other vehicles.

2. The vehicle control method according to claim 1, wherein the computer performs the gradual deceleration processing when an adjacent lane adjacent to the lane in which the vehicle is traveling is a low-speed lane in which vehicles traveling at a speed slower than the vehicle traveling in the lane in which the other vehicle is located are located in the low-speed lane.

3. A vehicle control method according to claim 1 or claim 2, wherein the computer performs the stepwise deceleration process when the other vehicle is located behind the host vehicle.

4. A vehicle control method according to any one of claims 1 to 3, wherein the computer prohibits the stepwise deceleration process when the other vehicle is located ahead of the host vehicle.

5. A vehicle control method according to any one of claims 1 to 4, wherein the computer, as the stepwise deceleration process, makes a first deceleration larger than second and subsequent decelerations.

6. A vehicle control method according to any one of claims 1 to 5, wherein the computer, in the stepwise deceleration process, increases the first deceleration as the distance between the host vehicle and the other vehicle increases.

7. A vehicle control method according to any one of claims 1 to 5, wherein the computer, as part of the stepwise deceleration process, extends the duration of the first deceleration as the distance between the host vehicle and the other vehicle increases.

8. A vehicle control method as described in any one of claims 1 to 7, wherein the computer detects congestion in each lane on a driving route on which the vehicle is traveling, and when the vehicle's lane and at least one adjacent lane exist on the driving route, congestion is detected in the vehicle's lane, and congestion is not detected in at least one adjacent lane, performs the gradual deceleration processing based on the condition of the relative positional relationship between the vehicle and the other vehicle.

9. A vehicle control device comprising: a relative position detection unit that detects the relative positional relationship between the host vehicle and other vehicles around it; a target speed calculation unit that, when a deceleration control request to decelerate the vehicle speed of the host vehicle traveling by autonomous driving is acquired, calculates a target speed according to the deceleration control request; and a deceleration control unit that performs a stepwise deceleration process to decelerate the speed of the host vehicle to the target speed by gradually changing the deceleration according to the relative positional relationship between the host vehicle and the other vehicles.

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