Vehicle control device, vehicle control method, and storage medium

Abstract

The present application relates to a vehicle control device, a vehicle control method, and a computer program for vehicle control. The vehicle control device has a determination section (31) that determines whether to transfer the subject of driving control of a vehicle (10) in automatic driving control to a driver, a notification processing section (32) that notifies a request for driving replacement via a notification device (5) in a case where the subject of driving control is transferred to the driver, and a control section (33) that performs deceleration control on the vehicle (10) when a prescribed timing after a notification timing of the driving replacement request is reached, and the speed of the vehicle (10) becomes equal to or lower than a prescribed speed threshold before a prescribed period from the notification timing elapses, and a handover operation of driving performed by the driver is not sensed, and continues the deceleration control on the vehicle (10) even after the prescribed period elapses.

Description

Technical Field

[0001] This invention relates to a vehicle control device, a vehicle control method, and a computer program for controlling the movement of a vehicle. Background Technology

[0002] In the autonomous driving control of vehicles, when it becomes difficult to maintain the autonomous driving control for certain reasons, the main body of driving control is sometimes transferred from the vehicle's control unit to the driver. In such cases, a technique for smoothly completing the transfer of driving control has been proposed (see International Publication No. 2018 / 109868, Japanese Patent Application Publication No. 2018-144740, and Japanese Patent Application Publication No. 2017-97518).

[0003] The vehicle control device disclosed in International Publication No. 2018 / 109868 performs state change control based on the vehicle's driving environment. This state change control changes the vehicle's state when driving control is switched from automatic to manual or when a switch from automatic to manual is anticipated. Furthermore, as part of this state change control, the vehicle control device sets the vehicle's acceleration or deceleration to a lower value than the setpoint in acceleration or deceleration control when no state change control is performed.

[0004] Furthermore, regarding the control device for an automated driving vehicle disclosed in Japanese Patent Application Publication No. 2018-144740, in automated driving mode, until the deceleration initiated by the second braking device that slows down the vehicle begins, the control device switches from automated driving mode to manual driving mode based on the operation of any one of the steering operation member, braking operation member, or acceleration operation member. Additionally, in automated driving mode, after the deceleration initiated by the second braking device begins until the first braking device that maintains the vehicle's stopped state automatically operates, the control device switches from automated driving mode to manual driving mode based on the operation of any one of the steering operation member and acceleration operation member.

[0005] The automated driving assistance device disclosed in Japanese Patent Application Publication No. 2017-97518 sets a level based on the driver's state, indicating whether the driver can switch from automated driving to manual driving within a specified transition range. Furthermore, the automated driving assistance device reduces the vehicle's speed for all or part of the transition range during automated driving, according to the set level. If the reduced speed is lower than a minimum speed, the automated driving assistance device issues a warning to the driver or automatically stops the vehicle in a reversing zone.

[0006] When the driver transfers control of the vehicle from the control unit to the driver, the control unit notifies the driver of a driver handover request. However, if the driver fails to relinquish control of the vehicle even after a certain period has elapsed since the driver handover request, the vehicle's safety may be compromised. Summary of the Invention

[0007] Therefore, the object of the present invention is to provide a vehicle control device that can improve safety when the main body of driving control of the vehicle is handed over from the vehicle control device to the driver.

[0008] According to one embodiment, a vehicle control device is provided. This vehicle control device includes: a determination unit, in a vehicle under autonomous driving control, determining whether to transfer the main body of vehicle driving control to the driver; a notification processing unit, which, when the main body of vehicle driving control is transferred to the driver, notifies the driver of a driving change request via a notification device provided in the vehicle; and a control unit, which, when a predetermined time has elapsed after the notification time for the driving change request, performs deceleration control on the vehicle, and continues to perform deceleration control even after the predetermined time has elapsed if the vehicle speed is below a predetermined speed threshold before a predetermined period has elapsed from the notification time and no driving handover operation performed by the driver is sensed.

[0009] In this vehicle control device, it is preferable that if the vehicle speed is not lower than a predetermined speed threshold before a predetermined period has elapsed from the notification time, and no handover operation of driving performed by the driver is detected, the control unit stops the automatic driving control of the vehicle at the point when the predetermined period has elapsed.

[0010] In this case, preferably, when the steering wheel operation performed by the driver is sensed from the notification time until a predetermined period has elapsed, or when the driver's grip on the steering wheel and the driver's operation of the accelerator or brake are sensed, the control unit determines that a driving handover operation performed by the driver has been carried out. On the other hand, if a predetermined period has elapsed from the notification time, when the steering wheel operation performed by the driver is sensed, or when the driver's acceleration or braking operation without gripping the steering wheel is sensed, the control unit determines that a driving handover operation performed by the driver has been carried out.

[0011] Alternatively, preferably, when the vehicle speed is below a predetermined speed threshold, the control unit continues to decelerate the vehicle as long as no operation of the accelerator or brake performed by the driver as a handover operation is sensed. On the other hand, when the vehicle speed is above the predetermined speed threshold, the control unit stops the automatic driving control of the vehicle when it senses a steering wheel operation performed by the driver as a handover operation or a predetermined operation performed by the driver including gripping the steering wheel.

[0012] Moreover, preferably, the control unit adjusts the prescribed speed threshold according to the gradient of the road on which the vehicle is traveling.

[0013] Alternatively, preferably, the control unit determines whether there is a risk that the vehicle will collide with other objects due to the acceleration of the vehicle after the transfer of driving control to the driver, based on the reason for the determination that the main body of driving control of the vehicle is transferred to the driver or the conditions around the vehicle, and only if the determination that there is such a risk, continues to decelerate the vehicle even after a predetermined period has elapsed.

[0014] According to another embodiment, a vehicle control method is provided. This vehicle control method includes: in a vehicle under autonomous driving control, determining whether to transfer the main body of vehicle driving control to a driver; if the main body of vehicle driving control is transferred to the driver, notifying the driver of a driving change request via a notification device provided in the vehicle; when a predetermined time has elapsed after the notification time of the driving change request, performing deceleration control on the vehicle; and continuing vehicle deceleration control even after the predetermined time has elapsed if the vehicle speed is below a predetermined speed threshold before a predetermined period has elapsed from the notification time and no driving handover operation performed by the driver is sensed.

[0015] According to another embodiment, a vehicle control computer program is provided. This vehicle control computer program includes commands for causing a processor mounted in a vehicle to perform the following steps: in a vehicle under autonomous driving control, determining whether to transfer the main body of vehicle driving control to the driver; if the main body of vehicle driving control is transferred to the driver, notifying the driver of a driving change request via a notification device provided in the vehicle; when a predetermined time elapses after the notification time for the driving change request, performing deceleration control on the vehicle; and continuing vehicle deceleration control even after the predetermined time elapses if the vehicle speed is below a predetermined speed threshold before a predetermined period has elapsed from the notification time and no driving handover operation performed by the driver is sensed.

[0016] The vehicle control device disclosed herein has the effect of improving safety when the main body of driving control of the vehicle is handed over from the vehicle control device to the driver. Attached Figure Description

[0017] Figure 1 It is a schematic diagram of a vehicle control system equipped with vehicle control devices.

[0018] Figure 2 This is a hardware configuration diagram of an electronic control device as one embodiment of a vehicle control device.

[0019] Figure 3 It is a functional block diagram of the processor of the electronic control device related to vehicle control processing.

[0020] Figure 4A This is a diagram illustrating the duration of automated driving control provided that the vehicle's speed does not fall below a specified speed threshold during the period from the time the notification is given until the specified period has elapsed.

[0021] Figure 4B This is a diagram illustrating the duration of automated driving control, including deceleration control, when the vehicle's speed is below a predetermined speed threshold during the period from the notification time until the specified period has elapsed.

[0022] Figure 5 It is a flowchart of the vehicle control and processing actions.

[0023] Figure 6 This is a flowchart of the vehicle control process in a modified example. Detailed Implementation

[0024] The vehicle control device, the vehicle control method executed on the vehicle control device, and the computer program for vehicle control will be described below with reference to the accompanying drawings. When the vehicle control device transfers control of the vehicle to the driver for some reason, it executes deceleration control to slow the vehicle down at a predetermined time. However, when the vehicle control device transfers control of the vehicle to the driver and stops deceleration control after a certain period has elapsed since the notification of a Transition Demand (TD), the vehicle may sometimes accelerate due to creeping or other phenomena, depending on its speed. Furthermore, it is difficult to achieve deceleration through engine braking. As a result, vehicle safety may be compromised.

[0025] Therefore, if the vehicle speed falls below a predetermined speed threshold before a specified period has elapsed since the notification of the driver replacement request, and no driver handover operation is detected, the vehicle control device continues to decelerate the vehicle even after the specified period has elapsed. On the other hand, if the vehicle speed is not lower than the predetermined speed threshold, the vehicle control device transfers full control of the vehicle to the driver even if no driver handover operation is detected, once the specified period has elapsed since the notification of the driver replacement request.

[0026] Figure 1 This is a schematic diagram of a vehicle control system equipped with vehicle control devices. Furthermore, Figure 2 This is a hardware configuration diagram of an electronic control unit as one embodiment of a vehicle control device. In this embodiment, the vehicle control system 1, mounted on and controlling the vehicle 10, includes a GPS (Global Positioning System) receiver 2, a camera 3, a storage device 4, a user interface 5, and an electronic control unit (ECU) 11, which is an example of a vehicle control device. The GPS receiver 2, camera 3, and storage device 4 are communicatively connected to the ECU 11 via a standard in-vehicle network such as a controller area network. Furthermore, the ECU 11 is connected to a steering device 6 including a steering wheel, a touch sensor 7 located on the steering wheel and sensing the driver's contact with the steering wheel, an acceleration device 8 including an accelerator pedal, and a braking device 9 including a brake pedal. In addition, the ECU 11 is connected to a vehicle speed sensor (not shown) that measures the vehicle speed of the vehicle 10. It should be noted that the vehicle control system 1 may also include a distance sensor (not shown) such as a LiDAR (Light Detection and Ranging) or radar that measures the distance from the vehicle 10 to objects existing around the vehicle 10. Furthermore, the vehicle control system 1 may also have other in-vehicle equipment such as a wireless communication terminal (not shown) for wireless communication with other devices or a navigation device (not shown) for retrieving a driving plan route to the destination.

[0027] GPS receiver 2 receives GPS signals from GPS satellites at a predetermined period and uses the received GPS signals to determine the location of vehicle 10. Furthermore, GPS receiver 2 outputs positioning information, representing the location of vehicle 10 based on GPS signals, to ECU 11 via the in-vehicle network at a predetermined period. It should be noted that vehicle control system 1 may also have a receiver based on other satellite positioning systems instead of GPS receiver 2.

[0028] Camera 3 is an example of an external vehicle sensor, comprising a two-dimensional detector consisting of an array of photoelectric conversion elements sensitive to visible light, such as a CCD (Charge Coupled Device) or C-MOS (Complementary Metal Oxide Semiconductor), and an imaging optical system that images the area to be photographed onto this two-dimensional detector. Camera 3 is mounted, for example, facing forward of vehicle 10 inside the vehicle compartment. Camera 3 captures images of the area in front of vehicle 10 at predetermined shooting intervals (e.g., 1 / 30 to 1 / 10 of a second), generating an image of that area. The image obtained by camera 3 is an example of an external vehicle sensor signal representing the surrounding conditions of the vehicle. The image obtained by camera 3 can be a color image or a grayscale image. It should be noted that multiple cameras with different shooting directions or focal lengths may also be provided in vehicle 10. For example, a camera facing the rear of vehicle 10 may also be provided.

[0029] Whenever a camera 3 generates an image, it outputs the generated image to ECU 11 via the in-vehicle network.

[0030] Storage device 4 is an example of a storage unit, such as a hard disk drive or a non-volatile semiconductor memory. Furthermore, storage device 4 stores a high-precision map used in the vehicle's autonomous driving control. It should be noted that the high-precision map includes, for example, information representing road markings such as lane lines or stop lines, and information representing road signs, wherein each road is a road included in the defined area represented by the high-precision map. The high-precision map is an example of map information.

[0031] Furthermore, the storage device 4 may also include a processor for performing high-precision map update processing and processing related to high-precision map readout requests from the ECU 11. Additionally, the storage device 4 may, for example, send a high-precision map acquisition request along with the vehicle 10's current location to a map server via a wireless communication terminal (not shown) whenever the vehicle 10 moves a predetermined distance. Furthermore, the storage device 4 may also receive a high-precision map of a predetermined area surrounding the vehicle 10's current location from the map server via the wireless communication terminal. Moreover, when the storage device 4 receives a high-precision map readout request from the ECU 11, it extracts a relatively narrow area from the stored high-precision map, including the vehicle 10's current location, and outputs it to the ECU 11 via the in-vehicle network.

[0032] User interface 5 is an example of a notification device or notification unit, such as a display device with an LCD screen or a touch panel display. User interface 5 is located inside the vehicle 10 facing the driver, for example, near the instrument panel. User interface 5 displays prescribed information received from ECU 11 via the in-vehicle network or a request for driver replacement, either via icons or text information, thereby reporting the information or notification to the driver. User interface 5 may also have one or more light sources on the instrument panel, speakers installed in the passenger compartment, or vibration devices installed on the steering wheel or driver's seat. In this case, user interface 5 outputs the prescribed information or notification received from ECU 11 via the in-vehicle network in the form of an audio signal, thereby reporting the information or notification to the driver. Alternatively, user interface 5 may also use signals received from ECU 11 via the in-vehicle network to cause the vibration device to vibrate, thereby reporting the prescribed information or notification to the driver through this vibration. Alternatively, user interface 5 may also use signals received from ECU 11 via the in-vehicle network to cause the light source to illuminate or flash, thereby reporting the prescribed information or notification.

[0033] When the ECU 11 applies an autonomous driving mode to the vehicle 10 based on driver instructions received via the user interface 5, it performs autonomous driving control of the vehicle 10. Furthermore, while the vehicle 10 is under autonomous driving control, the ECU 11 determines whether autonomous driving control can continue. If it determines that autonomous driving control cannot continue, it performs processing to transfer control of the vehicle 10 from the ECU 11 to the driver. Moreover, when control of the vehicle 10 is transferred to the driver—that is, when a manual driving mode is applied to the vehicle 10—the ECU 11 can also perform functions that assist the driver in driving the vehicle 10, such as lane keeping assist or collision avoidance assist.

[0034] like Figure 2 As shown, ECU11 has a communication interface 21, a memory 22, and a processor 23. The communication interface 21, the memory 22, and the processor 23 can be configured as separate circuits, or they can be integrated into a single integrated circuit.

[0035] The communication interface 21 has an interface circuit for connecting the ECU 11 to the in-vehicle network. Furthermore, whenever the communication interface 21 receives location information from the GPS receiver 2, it transmits that location information to the processor 23. Additionally, whenever the communication interface 21 receives an image from the camera 3, it transmits the received image to the processor 23. Moreover, the communication interface 21 transmits a high-precision map read from the storage device 4 to the processor 23. Furthermore, the communication interface 21 outputs signals representing specified information or notifications received from the processor 23 to the user interface 5 via the in-vehicle network.

[0036] Furthermore, the communication interface 21 is connected to the steering device 6, the touch sensor 7, the accelerator device 8, and the braking device 9. When the communication interface 21 receives a steering wheel torque sensing signal indicating the torque applied to the steering wheel from the steering device 6, it transmits the steering wheel torque sensing signal to the processor 23. Additionally, when the communication interface 21 receives a sensing signal indicating that the driver is gripping the steering wheel from the touch sensor 7, it transmits that sensing signal to the processor 23. Furthermore, when the communication interface 21 receives an acceleration operation signal indicating the amount of accelerator pedal pressure from the accelerator device 8, it transmits that acceleration operation signal to the processor 23. Finally, when the communication interface 21 receives a braking operation signal indicating the amount of brake pedal pressure from the braking device 9, it transmits that braking operation signal to the processor 23.

[0037] Memory 22 is another example of a storage unit, such as a volatile semiconductor memory and a non-volatile semiconductor memory. Furthermore, memory 22 stores various algorithms and data used in the vehicle control processing executed by the processor 23 of ECU 11. For example, memory 22 stores speed thresholds and messages used to notify the driver in a driver replacement request. In addition, memory 22 stores parameters such as the mounting position, shooting direction, and focal length of camera 3. Moreover, memory 22 stores various parameters used to determine the object detection sensor, high-precision maps read from storage device 4, and driving plan routes generated by the navigation device. Furthermore, memory 22 temporarily stores information received by ECU 11 during vehicle control processing and various data generated during vehicle control processing. It should be noted that the information received by ECU 11 during vehicle control processing includes images of the vehicle 10's surroundings, positioning information, steering wheel grip sensing signals, steering wheel torque sensing signals, acceleration operation signals, and braking operation signals.

[0038] The processor 23 has one or more CPUs (Central Processing Units) and their peripheral circuitry. The processor 23 may also have other arithmetic circuitry such as logic units, numerical processing units, or graphics processing units. Furthermore, the processor 23 performs vehicle control processing for the vehicle 10.

[0039] Figure 3 This is a functional block diagram of processor 23 related to vehicle control processing. Processor 23 includes a decision unit 31, a notification processing unit 32, and a control unit 33. These units of processor 23 are, for example, functional modules implemented by a computer program that operates on processor 23. Alternatively, these units of processor 23 may also be dedicated arithmetic circuits provided on processor 23.

[0040] During the period when vehicle 10 is under autonomous driving control, determination unit 31 determines whether to transfer the driving control of vehicle 10 to the driver. For example, if vehicle 10 can no longer continue autonomous driving while traveling a predetermined distance from its current position as shown in the latest positioning information, determination unit 31 determines to transfer the control of vehicle 10 to the driver. Specifically, if vehicle 10 deviates from the range represented by the high-precision map before traveling a predetermined distance from its current position along the planned route or the road it is currently traveling on, vehicle 10 can no longer continue autonomous driving. Therefore, determination unit 31 determines to transfer the control of vehicle 10 to the driver. For example, suppose that although information related to highways is represented in the high-precision map, information related to general roads is not represented. In this case, for example, a highway interchange becomes a location that deviates from the high-precision map.

[0041] Furthermore, the determination unit 31 can also determine whether the autonomous driving of the vehicle 10 can continue based on the surrounding conditions of the vehicle 10. Moreover, if the determination unit 31 determines that the autonomous driving of the vehicle 10 cannot continue, it can decide to hand over control of the vehicle 10 to the driver. For example, if another vehicle cuts in front of the vehicle 10 in the lane in which the vehicle 10 is traveling, the determination unit 31 may consider this as a failure to continue autonomous driving and decide to hand over control of the vehicle 10 to the driver. Additionally, based on traffic information received via a wireless communication terminal (not shown), it may sometimes be notified that road construction, lane restrictions, or congestion are occurring within a specified distance from the current position of the vehicle 10 along the road or planned route it is currently traveling on. In such cases, the determination unit 31 may also decide to hand over control of the vehicle 10 to the driver. Alternatively, when the ECU 11 receives a signal indicating a malfunction from the camera 3 or a distance sensor (not shown), the ECU 11 considers this as a failure to continue autonomous driving control of the vehicle 10, and the determination unit 31 decides to hand over control of the vehicle 10 to the driver.

[0042] When control is transferred due to other vehicles entering the lane, the determination unit 31, for example, inputs an image representing the surroundings of vehicle 10 generated by camera 3 into the recognizer, thereby detecting areas in the image representing other vehicles and areas representing lane markings. As such a recognizer, the determination unit 31 may utilize, for example, a deep neural network (DNN) with a convolutional neural network (CNN) architecture, such as a Single Shot MultiBox Detector (SSD) or Faster R-CNN. Alternatively, as such a recognizer, the determination unit 31 may also utilize a DNN with a self-attention network (SAN) architecture, such as a Visiontransformer. Alternatively, as such a recognizer, the determination unit 31 may also utilize a DNN for semantic segmentation, such as a Fully Convolutional Network (FCNN) or U-Net, which identifies the category of the object represented by each pixel. Alternatively, the decision unit 31 can also utilize a recognizer based on other machine learning methods, such as the AdaBoost recognizer. Such a recognizer is pre-learned using a number of training images representing vehicles or lane markings, following a prescribed learning method such as the backpropagation algorithm, in order to detect other vehicles and lane markings from the images.

[0043] The determination unit 31 defines the lane dividing line that is closest to the center line on both the left and right sides of the center line in the horizontal direction of the detected lane dividing lines as the lane dividing line that divides the lane. Furthermore, the determination unit 31 defines the area on the image that is enclosed by the respective lane dividing lines that divide the lane as the area corresponding to the lane. Moreover, the determination unit 31 determines the other vehicles located in the area corresponding to the lane among the detected other vehicles as the leading vehicles ahead of vehicle 10 in the lane. The determination unit 31 performs the above processing on each of a series of images obtained from the camera 3 in a time sequence, thereby detecting other vehicles and lane dividing lines from each image, and determining the leading vehicle traveling in the lane based on the detection results. Furthermore, the determination unit 31 applies a tracking method such as KLT tracker to the area indicating a leading vehicle in the latest image and the area indicating other vehicles in past images, thereby tracking the leading vehicle in a retrospective manner. Furthermore, if the result of the tracking is that the preceding vehicle detected in the latest image was in a lane different from the current lane during the just-past specified period, the determination unit 31 can determine that the preceding vehicle has cut in front of the vehicle 10.

[0044] When the determination unit 31 receives a determination that the control of the vehicle 10 should be transferred to the driver, it notifies the notification processing unit 32 and the control unit 33 of the determination result. Furthermore, the determination unit 31 notifies the control unit 33 of a signal indicating the phenomenon that caused the determination to transfer the control of the vehicle 10 to the driver.

[0045] When the determination unit 31 notifies the driver that the control of the vehicle 10 will be transferred to the driver, the notification processing unit 32 notifies the driver of a driver replacement request via the user interface 5. At this time, the notification processing unit 32 causes the display device of the user interface 5 to display a message or icon indicating the driver replacement request, or to illuminate or flash a light source corresponding to the request. Alternatively, the notification processing unit 32 causes the speaker of the user interface 5 to output an sound signal indicating the request. Alternatively, the notification processing unit 32 causes the vibration device of the user interface 5 to vibrate according to a vibration mode (vibration period or vibration intensity) corresponding to the request. It should be noted that if the user interface 5 has two or more of the aforementioned devices, the notification processing unit 32 may also notify the driver of the driver replacement request via each or any one of the two or more devices.

[0046] The notification processing unit 32 notifies the control unit 33 of the notification timed request to send a driver replacement request to the driver via the user interface 5.

[0047] During the application of autonomous driving mode to vehicle 10, control unit 33 performs autonomous driving control on vehicle 10. Control unit 33 continues autonomous driving control until a predetermined time has elapsed after a notification timer requesting a driver replacement, or until a driver handover operation is detected. When the predetermined timer is reached, as part of the autonomous driving control scheme, control unit 33 begins deceleration control to slow vehicle 10 down at a predetermined deceleration rate. Furthermore, control unit 33 keeps track of the elapsed time from the notification timer. If the speed of vehicle 10 falls below a predetermined speed threshold and no driver handover operation is detected, control unit 33 continues deceleration control of vehicle 10 even after the predetermined time has elapsed. Conversely, if the speed of vehicle 10 is not lower than the predetermined speed threshold and no driver handover operation is detected before the predetermined time has elapsed from the notification timer, control unit 33 transfers control of vehicle 10 to the driver regardless of whether deceleration control has been implemented.

[0048] The control unit 33 determines whether the speed of the vehicle 10 is lower than the speed threshold by comparing the measured value of the speed of the vehicle 10 received by the ECU 11 from the vehicle speed sensor (not shown) with the speed threshold.

[0049] It should be noted that the prescribed timing for initiating deceleration control is, for example, the timing when the vehicle 10's speed falls below a prescribed speed threshold after the notification timing. Alternatively, the prescribed timing may be the notification timing itself of the driver's request for a replacement. Alternatively, the prescribed timing may be the timing after a prescribed waiting period has elapsed since the notification timing. However, the prescribed waiting period is set to be shorter than the aforementioned prescribed period, for example, 1 to 2 seconds. Furthermore, the prescribed period may be set to, for example, 3 to 5 seconds. Moreover, the prescribed speed threshold is, for example, set to the upper limit of the speed at which the vehicle 10 might accelerate due to creeping, for example, 10 km / h to 20 km / h.

[0050] During the autonomous driving control of vehicle 10, control unit 33 controls various parts of vehicle 10 to ensure that vehicle 10 travels at a predetermined speed. The predetermined speed can be set by the driver via user interface 5, or determined by referring to a high-precision map and the current position of vehicle 10 as shown by the latest positioning information, based on the speed limit of the road on which vehicle 10 is traveling. Furthermore, in the presence of a preceding vehicle traveling in the same lane, control unit 33 can also control the speed of vehicle 10 to maintain a constant distance between the preceding vehicle and vehicle 10. It should be noted that the distance between the preceding vehicle and vehicle 10 is estimated based on the area representing vehicle 10 in the image generated by camera 3. That is, the lower end of the area representing vehicle 10 in the image is estimated to represent the position where the preceding vehicle contacts the road surface. Furthermore, the lower end of this area in the image represents the orientation from camera 3 towards the position where the preceding vehicle contacts the road surface. Therefore, the control unit 33 can estimate the distance between the vehicle 10 and the preceding vehicle based on the orientation viewed from the camera 3, corresponding to the lower position of the area on the image where the vehicle 10 is represented, and the installation height of the camera 3. Furthermore, if the vehicle 10 is equipped with a distance sensor such as a LiDAR sensor, the control unit 33 can also set the distance measured by the distance sensor up to an object existing in the direction in front of the vehicle 10 as the distance between the vehicle 10 and the preceding vehicle.

[0051] The control unit 33 sets the accelerator opening or braking amount so that the vehicle 10 reaches the speed determined as described above. Furthermore, the control unit 33 calculates the fuel injection amount according to the set accelerator opening and outputs a control signal corresponding to the fuel injection amount to the fuel injection device of the engine of the vehicle 10. Alternatively, the control unit 33 calculates the electrical charge supplied to the motor according to the set accelerator opening and controls the motor drive circuit to supply the electrical charge to the motor. Moreover, the control unit 33 outputs a control signal corresponding to the set braking amount to the braking device 9.

[0052] Furthermore, for the control unit 33, when deceleration control is initiated, during the period of deceleration control execution, the deceleration of the vehicle 10 is set to a predetermined deceleration rate (e.g., 0.7 m / s). 2 The accelerator opening or braking amount is set in a certain manner. Furthermore, the control unit 33 calculates the fuel injection amount according to the set accelerator opening and outputs a control signal corresponding to that fuel injection amount to the fuel injection device of the engine of the vehicle 10. Alternatively, the control unit 33 calculates the electrical quantity supplied to the motor according to the set accelerator opening and controls the motor drive circuit by supplying that electrical quantity to the motor. Moreover, the control unit 33 outputs a control signal corresponding to the set braking amount to the braking device 9.

[0053] Furthermore, for the control unit 33, when the speed of the vehicle 10 becomes 0 while the deceleration control is in progress, in order to keep the vehicle 10 stationary, the accelerator opening can be set to 0 or the braking amount can be made greater than a specified value.

[0054] The control unit 33 senses a handover of driving operations performed by the driver based on at least one of the driver's steering wheel operation, steering wheel grip, acceleration device operation, and braking operation. Furthermore, when the control unit 33 senses a handover of driving operations performed by the driver, it subsequently transfers control of the vehicle 10 to the driver. Then, it performs driving control of the vehicle 10 according to the driver's driving operations.

[0055] For example, from the time the notification is scheduled until the specified period has elapsed, the control unit 33 determines that the driver has performed a handover operation based on any one of (a) to (c) below.

[0056] (a) When the torque applied to the steering wheel, as indicated by the steering wheel torque sensing signal received from the steering device 6, reaches or exceeds a predetermined torque value. That is, when the driver's steering wheel operation is sensed.

[0057] (b) When the ECU11 receives a sensing signal from the touch sensor 7 indicating that the driver is holding the steering wheel, and the acceleration operation signal received from the accelerator device 8 indicates that the amount of accelerator pedal depressed is greater than or equal to a predetermined amount. That is, when it senses that the driver is holding the steering wheel and operating the accelerator device 8.

[0058] (c) When the ECU11 receives a sensing signal from the touch sensor 7 indicating that the driver is holding the steering wheel, and receives a braking operation signal from the braking device 9 indicating that the amount of brake pedal pressure is greater than a predetermined amount. That is, when it senses that the driver is holding the steering wheel and operating the braking device 9.

[0059] Furthermore, even if the driver is not holding the steering wheel, the control unit 33 can determine that the driver has handed over control of the vehicle after a predetermined period has elapsed since the notification time. That is, the determination conditions in (b) and (c) above can omit the requirement that the ECU 11 receives a sensing signal from the touch sensor 7 indicating that the driver is holding the steering wheel. Thus, by relaxing the necessary condition for handing over control after a predetermined period has elapsed since the notification time, the control unit 33 can prevent the vehicle 10 from accelerating unexpectedly after the control is transferred to the driver, and improve driver convenience.

[0060] Furthermore, after the vehicle 10 stops, when the control unit 33 senses that the driver has operated the accelerator or brake, or senses that the driver has shifted the gear lever to parking, it can also determine that the driver has handed over driving. Alternatively, after the vehicle 10 stops, when the electric parking brake is released, the control unit 33 can also determine that the driver has handed over driving.

[0061] Figure 4A This is a schematic diagram illustrating the duration of autonomous driving control when the vehicle 10's speed is not lower than a specified speed threshold during the period from the notification time until the specified period has elapsed. Figure 4B This is a diagram illustrating the duration of automated driving control, including deceleration control, when the vehicle 10's speed is below a predetermined speed threshold during the period from the notification time until the specified period has elapsed. Figure 4A and Figure 4B In the diagram, the horizontal axis represents elapsed time, and the vertical axis represents the speed of vehicle 10. Furthermore, in... Figure 4A In the graph 401, the speed of vehicle 10 changes over time. Similarly, in... Figure 4B In the figure, curve 402 represents the time-varying speed of vehicle 10.

[0062] like Figure 4A As shown, the speed of vehicle 10 remains constant until time t1. Then, at time t1, a request for a driver change is notified to the driver. That is, time t1 becomes the notification time. After notification time t1, automatic driving control of vehicle 10 continues. For example, although the speed of vehicle 10 changes over time due to its relationship with the preceding vehicle, the speed of vehicle 10 is above the speed threshold Thv during the period from notification time t1 until the specified period P has elapsed. Furthermore, no driver handover operation is detected during the period from notification time t1 until the specified period P has elapsed. Therefore, in this example, at time t2, after the specified period P has elapsed from notification time t1, control is transferred to the driver, and after time t2, the speed of vehicle 10 becomes the speed based on the driving operation performed by the driver. In this example, the speed of vehicle 10 does not decrease significantly when control is transferred to the driver; therefore, if the driver does not perform a driving operation, the speed of vehicle 10 will also decelerate through engine braking after time t2.

[0063] On the other hand, Figure 4BIn the example shown, the speed of vehicle 10 is kept constant until time t1. Then, at time t1, a driver handover request is notified to the driver. In this example, at time t2 after the notification time t1, the speed of vehicle 10 falls below the speed threshold Thv, and deceleration control is implemented after time t2. Then, the speed of vehicle 10 decreases over time. In this case, deceleration control continues even after a predetermined period P has elapsed since the notification time t1, as long as no driver handover operation is detected. Then, when the speed of vehicle 10 reaches 0, the vehicle 10 remains stationary thereafter.

[0064] Figure 5 This is a flowchart of the vehicle control processing executed by processor 23. Processor 23 executes vehicle control processing according to the following flowchart.

[0065] The determination unit 31 of the processor 23 determines whether to transfer the main body of driving control of the vehicle 10 to the driver (step S101). Then, if it is determined that the main body of driving control of the vehicle 10 should be transferred to the driver, the notification processing unit 32 of the processor 23 notifies the driver of the driving replacement request via the user interface 5 (step S102).

[0066] After the timed notification of the driver's request for a driver change, the control unit 33 of the processor 23 determines whether a driver handover operation performed by the driver has been detected (step S103). If a driver handover operation performed by the driver is detected (step S103 - Yes), the control unit 33 stops the automatic driving control of the vehicle 10 (step S104). Then, the vehicle 10 is controlled according to the driving operation performed by the driver, and the ECU 11 terminates the vehicle control processing.

[0067] On the other hand, if no driving handover operation performed by the driver is detected (step S103 - No), the control unit 33 determines whether the speed of the vehicle 10 is higher than the predetermined speed threshold Thv (step S105). If the speed of the vehicle 10 is higher than the predetermined speed threshold Thv (step S105 - Yes), the control unit 33 determines whether a predetermined period has elapsed since the notification timer (step S106). If the predetermined period has elapsed since the notification timer (step S106 - Yes), the control unit 33 stops the automatic driving control of the vehicle 10 (step S104). Afterwards, the vehicle 10 is controlled according to the driving operation performed by the driver, and the ECU 11 terminates the vehicle control processing.

[0068] On the other hand, if the prescribed period has not elapsed since the notification time (step S106 - No), the control unit 33 continues to perform automatic driving control of the vehicle 10 while the driver has been notified of the request for a driver change (step S107). Then, the control unit 33 repeats the processing after step S103.

[0069] Furthermore, if the speed of vehicle 10 is below the predetermined speed threshold Thv in step S105 (step S105 - No), the control unit 33 continues to decelerate vehicle 10 while the driver is notified of a driver change request (step S108). Then, the control unit 33 repeats the processing after step S103.

[0070] As explained above, when the vehicle control device determines that it can no longer continue automatic vehicle control for a predetermined reason, it notifies the driver of a driver handover request. Furthermore, if the vehicle maintains a speed above a predetermined speed threshold from the time the driver handover request is notified until a predetermined period has elapsed, the vehicle control device transfers control to the driver at the point after the predetermined period has elapsed. Thus, the vehicle control device can reliably transfer control to the driver, assuming that the vehicle will not accelerate unrelated to the driver's intentions after control is transferred. On the other hand, when a predetermined time occurs after the time the driver handover request is not notified, the vehicle control device performs deceleration control. Furthermore, if the vehicle speed falls below a predetermined speed threshold before the predetermined period has elapsed from the time the notification is notified, and no driver handover operation is detected, the vehicle control device continues to perform deceleration control even after the predetermined period has elapsed. Therefore, this vehicle control device can prevent the vehicle from accelerating unexpectedly due to crawling, thus improving safety when the main driving control of the vehicle is handed over from the vehicle control device to the driver.

[0071] According to a variation, the control unit 33 can also switch the determination conditions for determining that the driver has performed a handover operation based on the vehicle speed. For example, when the speed of the vehicle 10 is below a predetermined speed threshold, the control unit 33 can determine that the driver has performed a handover operation only if either an acceleration or braking operation performed by the driver is performed. That is, when the speed of the vehicle 10 is below the predetermined speed threshold, the control unit 33 determines that the driver has performed a handover operation only if the determination conditions (b) or (c) above are met. It should be noted that in this variation, after a predetermined period has elapsed from the notification timing, the sensing signal received by the ECU 11 from the touch sensor 7 indicating that the driver is holding the steering wheel can be omitted from the determination conditions (b) and (c) above. Therefore, when the speed of the vehicle 10 is below the predetermined speed threshold, the control unit 33 continues to perform deceleration control as long as no acceleration or braking operation performed by the driver is sensed.

[0072] On the other hand, if the speed of vehicle 10 exceeds a predetermined speed threshold, even if any of the determination conditions (a) to (c) above are met—that is, when a predetermined operation including gripping the steering wheel is performed—the control unit 33 can determine that the driver has performed a handover operation. Alternatively, if the speed of vehicle 10 exceeds the predetermined speed threshold, the control unit 33 may determine that the driver has performed a handover operation simply by sensing that the driver has operated or gripped the steering wheel. That is, in the determination condition (b) above, the sensing of the operation of the accelerator device 8 performed by the driver can be omitted. Furthermore, in the determination condition (c) above, the sensing of the operation of the brake device 9 performed by the driver can be omitted.

[0073] Figure 6 This is a flowchart of the vehicle control processing in this modified example. The determination unit 31 of processor 23 determines whether to transfer the main driving control of vehicle 10 to the driver (step S201). Then, if it is determined that the main driving control of vehicle 10 should be transferred to the driver, the notification processing unit 32 of processor 23 notifies the driver of a driving change request via user interface 5 (step S202). Then, the control unit 33 of processor 23 determines whether the speed of vehicle 10 is higher than a predetermined speed threshold Thv (step S203).

[0074] If the speed of vehicle 10 exceeds the predetermined speed threshold Thv (step S203 - Yes), the control unit 33 determines whether any one of the determination conditions (a) to (c) above is satisfied (step S204). If any one of the determination conditions (a) to (c) above is satisfied, that is, if a driving handover operation performed by the driver is sensed (step S204 - Yes), the control unit 33 stops the automatic driving control of vehicle 10 (step S205). Afterwards, vehicle 10 is controlled according to the driving operation performed by the driver, and ECU 11 ends the vehicle control processing.

[0075] On the other hand, if none of the determination conditions in (a) to (c) above are met, that is, if no driving handover operation performed by the driver is sensed (step S204 - No), the control unit 33 continues to perform automatic driving control of the vehicle 10 (step S206). In this case, the driver is notified of the request for driving change. Then, the control unit 33 repeats the processing after step S203.

[0076] On the other hand, if the speed of vehicle 10 is below the predetermined speed threshold Thv in step S203 (step S203 - No), control unit 33 starts deceleration control (step S207). Then, control unit 33 determines whether either of the determination conditions (b) and (c) above is satisfied (step S208). It should be noted that, as described above, the sensing of the driver holding the steering wheel can be omitted in the determination conditions (b) and (c). If either of the determination conditions (b) and (c) above is satisfied, that is, if a handover operation of driving performed by the driver, including acceleration or braking, is sensed (step S208 - Yes), control unit 33 stops automatic driving control (step S205). Afterwards, vehicle 10 is controlled according to the driving operation performed by the driver, and ECU 11 ends vehicle control processing.

[0077] On the other hand, if none of the determination conditions in (b) and (c) above are met, that is, if no operation is sensed during acceleration or braking (step S208 - No), the control unit 33 continues to decelerate the vehicle 10 (step S209). In this case, the driver is notified of the request to maintain driving. Then, the control unit 33 repeats the processing after step S203.

[0078] It should be noted that, in this modified example, the control unit 33 can also transfer the main body of driving control to the driver when deceleration control is not applied, even if a predetermined period has elapsed since the notification time and no driving handover operation performed by the driver has been sensed.

[0079] According to this modified example, the vehicle control device sets the operation of the accelerator or brake by the driver as a necessary condition for driver handover when the vehicle speed is low, thereby preventing accidental acceleration of the vehicle when the driver has handed over the driving operation. Moreover, when the vehicle speed is high, the vehicle control device can perform driver handover based on operations other than accelerator and brake, thereby suppressing any impairment to the driver's convenience.

[0080] It should be noted that in the above-described embodiments or variations, the control unit 33 can also dynamically set the speed threshold based on the surrounding environment of the vehicle 10. For example, the control unit 33 can also adjust the speed threshold based on the gradient of the road on which the vehicle 10 is traveling. In this case, the control unit 33 can also set the speed threshold for the vehicle 10 when traveling on an uphill road to be lower than the speed threshold for the vehicle 10 when traveling on a flat road. This is because when the vehicle 10 is traveling on an uphill road, the likelihood of the vehicle 10 accelerating after the automatic driving control stops decreases. Conversely, the control unit 33 can also set the speed threshold for the vehicle 10 when traveling on a downhill road to be higher than the speed threshold for the vehicle 10 when traveling on a flat road. This is because when the vehicle 10 is traveling on a downhill road, the likelihood of the vehicle 10 accelerating after the automatic driving control stops increases. It should be noted that the control unit 33 can determine the gradient of the road on which the vehicle 10 is traveling by referring to the current position of the vehicle 10 shown in the latest positioning information and a high-precision map. According to this variation, the control unit 33 can adjust the speed threshold to an appropriate value.

[0081] Furthermore, in the above-described embodiments or variations, the control unit 33 may also determine whether there is a risk that the vehicle 10 will collide with other objects due to acceleration after the transfer of driving control to the driver. In this case, the control unit 33 determines whether such a risk exists based on the surrounding conditions of the vehicle 10 or the reason for the determination that the control of the vehicle 10 is transferred to the driver. Furthermore, if there is a risk that the vehicle 10 will collide with other objects due to acceleration, the control unit 33 performs the same processing as in the above-described embodiments. That is, even if the speed of the vehicle 10 is below a predetermined speed threshold, and a predetermined period has elapsed since the notification time of the driver change request, the control unit 33 continues to perform deceleration control as long as no driver handover operation is sensed. For example, if the reason for transferring control to the driver is determined to be the insertion of another vehicle in front of the vehicle 10, it is considered that there is a risk that the vehicle 10 will collide with other objects due to acceleration, and the control unit 33 performs the same processing as in the above-described embodiments. Furthermore, the control unit 33 can also determine whether the vehicle 10 is driving on a curve at the notification time of the driver replacement request by referring to the position of the vehicle 10 represented by the positioning information and a high-precision map. If the vehicle 10 is driving on a curve at the notification time, the control unit 33 performs the same processing as in the embodiment described above.

[0082] On the other hand, if the reason for the driver replacement request is that vehicle 10 exits an area covered by a high-precision map, it is sometimes assumed that there will be no immediate danger of vehicle 10 colliding with other objects after the control is handed over to the driver. In such cases, control unit 33 may, regardless of the speed of vehicle 10, stop the automatic driving control or deceleration control of vehicle 10 and hand over control to the driver if a predetermined period has elapsed since the notification time. Furthermore, if the automatic driving control requests acceleration of vehicle 10 during the notification time when the driver replacement request is notified, control unit 33 may not perform deceleration control itself.

[0083] Furthermore, the control unit 33 can determine, based on the distance, relative speed, and relative acceleration between vehicle 10 and the preceding vehicle, whether there is a risk of collision between vehicle 10 and the preceding vehicle even if the control is handed over and the driver does not perform any driving operation after a predetermined period has elapsed since the notification time. If such a risk exists, the control unit 33 can, as in the above-described embodiment, continue deceleration control if the speed of vehicle 10 falls below a predetermined speed threshold and no driving handover operation by the driver is detected after the predetermined period has elapsed since the notification time. Conversely, if there is no such risk, the control unit 33 can hand over control to the driver at a point in time after the predetermined period has elapsed since the notification time, regardless of the speed of vehicle 10. It should be noted that the control unit 33 performs the same processing as the determination unit 31 to detect the preceding vehicle from each of a series of images in a time sequence generated by the camera 3, and tracks the detected preceding vehicle, thereby calculating the time-varying distance between vehicle 10 and the preceding vehicle. Furthermore, the control unit 33 applies a predictive filter, such as a Kalman filter, to the time-varying changes in the inter-vehicle distance, thereby predicting the time-series changes in the inter-vehicle distance, relative speed, and relative acceleration after a predetermined period has elapsed since the notification time. If, based on this prediction, the control unit 33 predicts that vehicle 10 and the preceding vehicle will approach below a predetermined danger distance, it determines that there is a risk of collision between vehicle 10 and the preceding vehicle.

[0084] Alternatively, since deceleration control continues even after a predetermined period has elapsed since the notification time, as in the above-described embodiment, there is a risk of collision between vehicle 10 and a following vehicle traveling behind it in the same lane. In such cases, the control unit 33 may not perform deceleration control regardless of the speed of vehicle 10. Furthermore, the control unit 33 may hand over control to the driver at the point when the predetermined period has elapsed since the notification time. In this case, the control unit 33 performs the same processing as the determination unit 31 to detect following vehicles from each of a series of images in a time sequence generated by the camera 3, which is set to capture images behind vehicle 10. The control unit 33 tracks the detected following vehicles and thereby calculates the time-lapse change in the inter-vehicle distance between vehicle 10 and the following vehicles. The control unit 33 applies a prediction filter such as a Kalman filter to the time-lapse change in the inter-vehicle distance, thereby predicting the time-series changes in inter-vehicle distance, relative speed, and relative acceleration after the predetermined period has elapsed since the notification time. If the control unit 33 predicts, based on the prediction result, that vehicle 10 and a following vehicle will approach to within a specified danger distance, it determines that there is a risk of collision between vehicle 10 and the following vehicle.

[0085] Alternatively, the control unit 33 can switch control based on the deceleration obtained after the vehicle 10 has been inertially moving for a predetermined period since the notification time. In this case, the control unit 33 can calculate the deceleration corresponding to the speed of the vehicle 10 at the notification time by referring to a reference table showing the relationship between the speed and deceleration of the vehicle 10. It should be noted that such a reference table can be stored in advance in the memory 22. Furthermore, when the vehicle 10 is driven by a motor, the reference table can also show not only the relationship between the speed and deceleration of the vehicle 10, but also the relationship between the remaining battery capacity and deceleration of the vehicle 10. The control unit 33 can then calculate the deceleration corresponding to the speed of the vehicle 10 and the remaining battery capacity at the notification time by referring to the reference table. If the deceleration is less than a predetermined deceleration threshold, similar to the above embodiment, the control unit 33 can continue to perform deceleration control if the speed of the vehicle 10 is below the predetermined speed threshold and no driving handover operation performed by the driver has been sensed after a predetermined period since the notification time. Conversely, if the deceleration exceeds a predetermined deceleration threshold, the control unit 33 may not perform deceleration control regardless of the speed of the vehicle 10.

[0086] Thus, according to this modified example, the control unit 33 switches between whether to continue deceleration control when no handover operation by the driver is detected, based on the reason for determining that the main driving control of the vehicle 10 is transferred to the driver or the surrounding conditions of the vehicle 10. Therefore, the control unit 33 can ensure the safety of the vehicle 10 and can set a more appropriate timing for the handover of driving control to the driver.

[0087] Furthermore, in cases where automatic driving control continues even after a predetermined period has elapsed since the notification time, as in the aforementioned variation, the control unit 33 can strengthen the notification of the driver's request for a driving change when the predetermined period has elapsed. In this case, the control unit 33 may, for example, increase the brightness of the message or icon displayed on the user interface 5 for the driving change request, or change the color of the message or icon to a more prominent color, thereby strengthening the notification of the driving change request. Alternatively, the control unit 33 may increase the volume of the driving change request emitted from the speaker on the user interface 5, or strengthen the vibration of the vibration device on the user interface 5, thereby strengthening the notification of the driving change request. Moreover, if no driving handover operation performed by the driver is sensed even after a certain period has elapsed since the notification of the strengthened driving change request, the control unit 33 can activate the driver emergency response system. That is, as part of the emergency response system, the control unit 33 may sound the horn, illuminate the hazard warning lights, or connect to the emergency notification system (Helpnet) via a wireless communication terminal to notify of an emergency.

[0088] As described above, those skilled in the art can make various modifications within the scope of this invention depending on the manner in which it is implemented.

Claims

1. A vehicle control device, comprising: The determination unit determines, in a vehicle under autonomous driving control, whether to transfer the main driving control of the vehicle to the driver. The notification processing unit, when transferring the main control of the vehicle's driving to the driver, notifies the driver of a request for a driving change via a notification device provided in the vehicle; as well as The control unit, upon a predetermined time following a notification timer requesting a driver replacement, performs deceleration control on the vehicle. If the vehicle's speed falls below a predetermined speed threshold before a predetermined period has elapsed since the notification timer, and no driver handover operation by the driver is detected, the deceleration control continues even after the predetermined period has elapsed. If the vehicle's speed does not fall below the predetermined speed threshold before the predetermined period has elapsed since the notification timer, and no driver handover operation by the driver is detected, the automatic driving control of the vehicle is stopped at the point in time after the predetermined period has elapsed. The specified speed threshold is set as the upper limit of the speed at which the vehicle may accelerate due to crawling.

2. The vehicle control device according to claim 1, wherein, From the time of the notification until the specified period has elapsed, when the control unit senses steering wheel operation performed by the driver, or senses steering wheel grip performed by the driver and accelerator or brake operation performed by the driver, the control unit determines that the handover operation has been performed. On the other hand, if the specified period has elapsed since the notification time, the control unit determines that the handover operation has been performed when it senses steering wheel operation of the vehicle performed by the driver, or acceleration or braking operation performed by the driver without holding the steering wheel.

3. The vehicle control device according to claim 1, wherein, When the vehicle speed is below a predetermined speed threshold, the control unit continues to decelerate the vehicle as long as no accelerator or brake operation performed by the driver as part of the handover operation is sensed. On the other hand, when the vehicle speed is above the predetermined speed threshold, the control unit stops the automatic driving control of the vehicle when a steering wheel operation performed by the driver as part of the handover operation or a predetermined operation performed by the driver, including holding the steering wheel, is sensed.

4. The vehicle control device according to claim 1, wherein, The control unit adjusts the prescribed speed threshold according to the gradient of the road on which the vehicle is traveling.

5. The vehicle control device according to claim 1, wherein, The control unit determines whether there is a risk that the vehicle will collide with other objects due to the acceleration of the vehicle after the transfer of driving control to the driver, based on the reason for the determination that the main body of driving control of the vehicle is transferred to the driver or the conditions around the vehicle. Only if the determination is that there is a risk, the deceleration control of the vehicle will continue even after the specified period has elapsed.

6. A vehicle control method, comprising: In vehicles under autonomous driving control, a decision is made on whether to transfer the main driving control of the vehicle to the driver. When the main driving control of the vehicle is transferred to the driver, the driver is notified of the request for a driving change via a notification device located in the vehicle. When the specified time has elapsed since the notification of the request for driver replacement, the vehicle is decelerated. If the vehicle's speed falls below a predetermined speed threshold before a specified period has elapsed from the notification time, and no handover operation by the driver is detected, the vehicle's deceleration control will continue even after the specified period has elapsed. If the vehicle's speed does not fall below the predetermined speed threshold before the predetermined period has elapsed from the notification time, and no driver handover operation is detected, the automatic driving control of the vehicle will cease at the point in time after the predetermined period has elapsed. The specified speed threshold is set as the upper limit of the speed at which the vehicle may accelerate due to crawling.

7. A storage medium storing a vehicle control computer program, the vehicle control computer program being used to cause a processor mounted in a vehicle to perform the following steps: In the vehicle under autonomous driving control, a determination is made as to whether to transfer the main driving control of the vehicle to the driver. When the main driving control of the vehicle is transferred to the driver, the driver is notified of the request for a driving change via a notification device located in the vehicle. When the specified time has elapsed since the notification of the request for driver replacement, the vehicle is decelerated. If the vehicle's speed falls below a predetermined speed threshold before a specified period has elapsed from the notification time, and no handover operation by the driver is detected, the vehicle's deceleration control will continue even after the specified period has elapsed. If the vehicle's speed does not fall below the predetermined speed threshold before the predetermined period has elapsed from the notification time, and no driver handover operation is detected, the automatic driving control of the vehicle will cease at the point in time after the predetermined period has elapsed. The specified speed threshold is set as the upper limit of the speed at which the vehicle may accelerate due to crawling.

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