Operation control method and operation control device

Abstract

To provide an operation control method and an operation control device which can indicate to an occupant a time at which an operation mode can automatically return to an original operation mode, after the operation mode switches to an operation mode in which an operation support level is lower.SOLUTION: An operation control device 100 controls an own vehicle 20 using a first operation mode and a second operation mode that is lower in operation support level than the first operation mode; sets an automatic returning time which is a time at which the operation mode can automatically switch to the first operation mode, at a timing when the operation mode of the own vehicle 20 switches from the first operation mode to the second operation mode; and outputs to a user interface 16 information showing count-downs of remaining time up to a timing at which the automatic returning time elapses.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a driving control method and a driving control device for controlling driving of a host vehicle. [Background technology]

[0002] Patent document 1 describes a display device that displays to an occupant the remaining time until the driver of an autonomous vehicle can switch from autonomous driving mode to manual driving mode, based on the amount of time the driver's hands are not continuously in contact with the steering wheel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-109590 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the display device described in Patent Document 1 has a problem in that it cannot present to the occupant the time when the driving mode can be returned from the manual driving mode to the automatic driving mode again.

[0005] The problem that the present invention aims to solve is to provide a driving control method and a driving control device that can present to an occupant the time at which the driving mode will automatically return to the original driving mode after being switched to a driving mode with a lower driving assistance level. [Means for solving the problem]

[0006] The present invention solves the above problem by setting an automatic return time, which is the time during which the driving mode of the vehicle can automatically switch from the second driving mode to the first driving mode, starting from the time when the driving mode of the vehicle switches from a first driving mode to a second driving mode, counting down the remaining time from the current time to the time when the automatic return time has elapsed, and outputting information indicating the countdown of the remaining time to a user interface of the vehicle. Effect of the Invention

[0007] According to the present invention, it is possible to present to an occupant the time at which the driving mode can be automatically returned to the original driving mode after it has been switched to a driving mode with a lower driving assistance level. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing a configuration of an operation control device according to a first embodiment of the present invention. [Diagram 2] 2 is a diagram showing an example of a driving scene of a host vehicle controlled by the driving control device shown in FIG. 1. [Diagram 3] 3 is a flowchart showing the procedure of a driving control method performed by the driving control device shown in FIG. 1 in the driving scene shown in FIG. 2. [Figure 4] 3 is a flowchart showing another example of the procedure of the driving control method performed by the driving control device shown in FIG. 1 in the driving scene shown in FIG. 2. [Diagram 5] FIG. 6 is a diagram showing an example of a driving scene of a host vehicle controlled by a driving control device according to a second embodiment of the present invention. [Figure 6] 6 is a flowchart showing the procedure of a driving control method performed by the driving control device shown in FIG. 1 in the driving scene shown in FIG. 5. [Figure 7] 6 is a flowchart showing another example of the procedure of the driving control method performed by the driving control device shown in FIG. 1 in the driving scene shown in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First Embodiment The first embodiment will be described with reference to FIGS. Fig. 1 is a block diagram showing the configuration of a driving control device 100 and a vehicle 20 according to this embodiment. As shown in Fig. 1, the vehicle 20 includes the driving control device 100, a preceding vehicle detection device 12, a vehicle position detection device 13, a map database 14, an input device 15, and a user interface 16. Each of these devices is connected to each other, for example, via a Controller Area Network (CAN) or other in-vehicle LAN, or by wire.

[0010] The driving control device 100 has a processor 101 that executes the functions of the driving control device 100. The processor 101 is composed of a ROM (Read Only Memory) that stores a program for controlling the driving of the vehicle, a CPU (Central Processing Unit) that executes the program stored in the ROM, and a RAM (Random Access Memory) that functions as an accessible storage device. As the operating circuit, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc. can be used instead of or in addition to the CPU (Central Processing Unit). In addition, the processor 101 of the driving control device 100 has a driving mode control unit 1, a remaining time measurement unit 2, an output unit 3, an automatic return possible time setting unit 4, and a drive control unit 5. That is, the driving mode control unit 1, the remaining time measurement unit 2, the output unit 3, the automatic return possible time setting unit 4, and the drive control unit 5 execute programs for realizing each function of the driving control device 100. The functions realized by the operation mode control unit 1, remaining time measurement unit 2, output unit 3, automatic return possible time setting unit 4, and drive control unit 5 will be described later.

[0011] The preceding vehicle detection device 12 detects a preceding vehicle, which is another vehicle traveling ahead of the host vehicle 20. The preceding vehicle detection device 12 has either a forward camera that captures an image ahead of the host vehicle or a forward radar that detects a preceding vehicle or an obstacle ahead of the host vehicle, or both.

[0012] The vehicle position detection device 13 is composed of a GPS unit, a gyro sensor, a vehicle speed sensor, etc. The vehicle position detection device 13 detects radio waves transmitted from multiple satellite communications by the GPS unit, periodically acquires position information of the target vehicle (the vehicle 20), and detects the current position of the target vehicle based on the acquired position information of the target vehicle, angle change information acquired from the gyro sensor, and vehicle speed acquired from the vehicle speed sensor. The position information of the target vehicle detected by the vehicle position detection device 13 is output to the driving control device 100 at a predetermined time interval.

[0013] The map database 14 is a memory configured to store three-dimensional high-precision map information including position information of various facilities and specific points and to be accessible from the driving control device 100. The map database 14 stores high-precision digital map information (high-precision map, dynamic map). In this example, the stored high-precision map information is three-dimensional map information based on road shapes including height information detected when a data acquisition vehicle is used to travel on an actual road. The high-precision map information includes identification information of multiple lanes that a road has. The map information in the map database 14 includes three-dimensional position information on curved roads and / or lanes and the magnitude of the curve (e.g., curvature or curvature radius), merging points, branching points, and positions where the number of lanes is reduced. The high-precision map information also includes information on facilities such as service areas / parking areas.

[0014] The input device 15 includes an in-vehicle device that operates when operated by the driver. The input device 15 is, for example, a steering wheel, an accelerator pedal, a brake pedal, a navigation device, a turn signal, or other specific switches. The input device 15 may also be a button switch that allows input by manual operation by the driver, a touch panel arranged on a display screen, or a microphone that allows input by the driver's voice. When the input device 15 is operated by the driver, the information is output to the driving control device 100.

[0015] The user interface 16 is, for example, a display provided in a navigation device, a display built into a rearview mirror, a display built into a meter section, a head-up display projected on the windshield, a speaker provided in an audio device, etc. The user interface 16 presents the information output by the output unit 3 of the driving control device 100 to the driver.

[0016] Next, each component of the operation control device 100 will be described. The driving mode control unit 1 of the driving control device 100 can set a driving mode according to the driving support level, and can support the driving of the host vehicle according to the set driving mode. The driving support level is a level indicating the degree of intervention when the driving control device 100 supports the driving of the vehicle by the autonomous driving control function. The higher the driving support level, the lower the contribution of the driver to the driving of the vehicle. Specifically, the driving support level can be set using a definition based on SAE J3016 of the Society of Automotive Engineers (SAE). At driving support level 0, the driving operation of the host vehicle is entirely performed manually by the driver. At driving support level 1, the driving operation of the host vehicle is mainly performed by the driver's manual driving, but the driving control device 100 appropriately supports the manual driving of the driver by any of the functions such as automatic braking, following, and lane keeping. At driving assistance level 2, the driver is primarily responsible for the driving operation of the vehicle, but under certain conditions, the driving control device 100 can perform driving assistance by combining multiple functions from among functions such as automatic braking, following, and lane keeping. At driving assistance level 3, the driving control device 100 performs all driving tasks, but the driver must regain control and prepare to drive manually when requested by the driving control device 100. At driving assistance level 4, manual driving by the driver is not required, and the driving control device 100 can perform all driving tasks under certain conditions. At driving assistance level 5, the driving control device 100 can perform all driving tasks under all conditions. The classification of driving assistance levels is not limited to the classification according to the definition of the Society of Automotive Engineers, and the driving assistance levels may be defined based on ISO / TC204 of the International Organization for Standardization (ISO). In addition, the classification of driving assistance levels may be defined according to other standards as long as the classification is appropriate according to the degree of intervention of the driving control device 100.

[0017] The driving modes set by the driving mode control unit 1 include at least a first driving mode and a second driving mode having a driving assistance level lower than that of the first driving mode. The first driving mode corresponds to driving assistance level 3, and the second driving mode corresponds to driving assistance level 2. The driving mode control unit 1 appropriately switches the driving mode between the first driving mode and the second driving mode. The driving assistance levels of the first driving mode and the second driving mode are not limited to driving assistance level 3 and driving assistance level 2, respectively, as long as the driving assistance level of the second driving mode is set lower than the driving assistance level of the first driving mode. Therefore, the first driving mode may be a driving mode corresponding to driving assistance level 2, and the second driving mode may be a driving mode corresponding to driving assistance level 1. The first driving mode may be an automatic driving mode corresponding to driving assistance level 1 or higher, and the second driving mode may be a manual driving mode corresponding to driving assistance level 0. Furthermore, the first driving mode may be a hands-off mode, and the second driving mode may be a hands-on mode. Here, the hands-off mode is a mode in which the autonomous steering control function operates even when the driver takes his / her hands off the steering wheel, and the hands-on mode is a mode in which the autonomous steering control function does not operate when the driver is not holding the steering wheel. Whether or not the driver is holding the steering wheel is detected by a touch sensor provided on the steering wheel or a steering torque sensor of the EPS.

[0018] The autonomous steering control function is a function that controls the operation of the steering actuator to control the steering of the vehicle and assists the driver in steering the vehicle. The autonomous steering control function includes, for example, a lane center keeping function that controls the steering so that the vehicle travels near the center of the lane, a lane keeping function that controls the lateral position so that the vehicle travels in the same lane, a lane change assist function that moves the vehicle from the lane in which the vehicle is traveling to another lane, an overtaking assist function that moves the vehicle forward by passing beside another vehicle ahead (in the adjacent lane), and a route driving assist function that autonomously changes lanes to follow a route to a destination.

[0019] In addition, the driving mode control unit 1 of the driving control device 100 switches the driving mode from the first driving mode to the second driving mode when the driving situation of the host vehicle 20 traveling in the first driving mode satisfies the first switching condition. Furthermore, after the driving mode is switched from the first driving mode to the second driving mode, the driving mode control unit 1 automatically returns the driving mode from the second driving mode to the first driving mode when the driving situation of the host vehicle 20 satisfies the second switching condition before a predetermined automatic return possible time has elapsed. The driving situation of the host vehicle 20 is determined based on information acquired from at least one of the preceding vehicle detection device 12, the host vehicle position detection device 13, the map database 14, and the input device 15. The driving situation of the host vehicle 20 is, for example, the speed of the preceding vehicle and the status of the lane change operation (start, midway, completion). In addition, the automatic return possible time is set by the automatic return possible time setting unit 4 described later.

[0020] Here, the first switching condition in this embodiment is that the vehicle speed V1 of the other vehicle 21 (preceding vehicle) in front of the host vehicle 20 shown in FIG. 2 exceeds a predetermined threshold speed. The vehicle speed V1 of the other vehicle 21 is detected by the preceding vehicle detection device 12. The predetermined threshold speed is, for example, an upper limit speed of the followable speed at which the host vehicle 20 can travel following the other vehicle 21. Specifically, when the host vehicle 20 travels following the other vehicle 21 in a congested line of vehicles in the first driving mode, the driving mode control unit 1 of the driving control device 100 switches the first driving mode to the second driving mode when the traffic jam is cleared and the vehicle speed of the preceding vehicle 21 increases and exceeds the upper limit speed of the followable speed. The threshold speed is, for example, 60 km / h, but is not limited thereto.

[0021] Before switching the first driving mode to the second driving mode, the driving mode control unit 1 of the driving control device 100 notifies the driver that the first driving mode will be switched to the second driving mode via the user interface 16, and prompts the driver to grip the steering wheel. In addition, the driving mode control unit 1 of the driving control device 100 switches the driving mode from the first driving mode to the second driving mode after detecting that the driver has gripped the steering wheel.

[0022] In addition, the second switching condition in this embodiment is that the vehicle speed V1 of the other vehicle 21 shown in Fig. 2 becomes equal to or lower than a predetermined threshold speed. Specifically, when the host vehicle 20 re-enters the traffic jam queue after the traffic jam is temporarily cleared and the other vehicle 21 decelerates and the vehicle speed V1 becomes equal to or lower than the upper limit speed of the followable speed before the predetermined automatic return possible time has elapsed, the driving mode control unit 1 of the driving control device 100 switches the driving mode to automatically return from the second driving mode to the first driving mode.

[0023] In addition, the driving mode control unit 1 of the driving control device 100 does not automatically return the driving mode from the second driving mode to the first driving mode if the vehicle speed V1 of the other vehicle 21 does not become equal to or lower than the upper limit speed of the followable speed before the automatic return possible time has elapsed. In other words, if the driving situation of the vehicle 20 does not satisfy the second switching condition before the automatic return possible time has elapsed, the driving mode control unit 1 of the driving control device 100 switches the driving mode from the second driving mode to the first driving mode and returns it only when a driving mode switching request is received from the driver via the input device 15. The driving mode switching request is output to the driving mode control unit 1, for example, by the driver pressing a switch button for switching driving modes provided on the input device 15.

[0024] The drive control unit 5 of the drive control device 100 controls the driving of the vehicle based on the driving mode set by the driving mode control unit 1. For example, the drive control unit 5 controls the operation of the drive mechanism for adjusting the acceleration / deceleration and vehicle speed (including the operation of the internal combustion engine in an engine vehicle, the operation of the driving motor in an electric vehicle, and the torque distribution between the internal combustion engine and the driving motor in a hybrid vehicle) and the brake operation by using an autonomous speed control function. The drive control unit 5 also controls the steering control of the vehicle by controlling the operation of the steering actuator by using an autonomous steering control function. For example, the drive control unit 5 detects lane markers of the lane in which the vehicle is traveling, and controls the traveling position (lateral position) of the vehicle in the width direction so that the vehicle travels in the center of the lane in which the vehicle is traveling. The drive control unit 5 also controls the vehicle to overtake a preceding vehicle, change the traveling direction, and the like. The drive control unit 5 also controls the vehicle to turn right or left at an intersection or the like. Other known methods can also be used as the driving control method by the drive control unit 5.

[0025] In addition, the automatic return possible time setting unit 4 of the driving control device 100 sets an automatic return possible time, which is a time during which the driving mode of the vehicle 20 can automatically switch from the second driving mode to the first driving mode and return, starting from the timing when the driving mode of the vehicle 20 is switched from the first driving mode to the second driving mode. The automatic return possible time setting unit 4 sets the automatic return possible time according to the driving situation of the vehicle 20. Specifically, the automatic return possible time set by the automatic return possible time setting unit 4 differs between a case in which the driving mode control unit 1 switches between the first driving mode and the second driving mode based on the vehicle speed V1 of the other vehicle 21 and a case in which the driving mode control unit 1 switches between the first driving mode and the second driving mode based on the situation of the lane change operation of the vehicle 20. In addition, the automatic return possible time according to the driving situation of the vehicle 20 is determined in advance by an experiment, but may be changed according to the vehicle speed of the vehicle 20, etc.

[0026] Furthermore, the remaining time measurement unit 2 of the driving control device 100 starts counting down the remaining time from the present until the automatic return possible time has elapsed when the driving mode is switched from the first driving mode to the second driving mode. Specifically, if the automatic return possible time is set to 30 seconds, the remaining time measurement unit 2 executes a countdown from 30 seconds to 0 seconds, starting from the time when the driving mode of the vehicle 20 is switched from the first driving mode to the second driving mode.

[0027] The output unit 3 outputs information indicating the remaining time counted down by the remaining time measurement unit 2 to the user interface 16. When the user interface 16 is a display, the user interface 16 presents an image in which the remaining time being counted down is expressed in numbers to the occupant of the vehicle 20. The user interface 16 may also present to the occupant an image of a bar whose length gradually shortens in response to the length of the remaining time. When the user interface 16 is a speaker, the user interface 16 may also output a sound counting down the remaining time.

[0028] Next, the procedure of the driving control method using the driving control device 100 when another vehicle 21 is traveling ahead of the host vehicle 20 as shown in FIG. 2 will be described with reference to FIG. First, in step S1, the driving control device 100 determines whether or not the host vehicle 20 is being controlled in the first driving mode. If the host vehicle 20 is not being controlled in the first driving mode, the control ends.

[0029] If the host vehicle 20 is controlled in the first driving mode, the control proceeds to step S2. In step S2, the driving control device 100 determines whether the vehicle speed V1 of the other vehicle 21, which is the preceding vehicle, exceeds a threshold speed. If the vehicle speed V1 of the other vehicle 21 is equal to or less than the threshold speed, the control ends.

[0030] If the vehicle speed V1 of the other vehicle 21 exceeds the threshold speed, the control proceeds to step S3. In step S3, the driving mode control unit 1 of the driving control device 100 switches the driving mode from the first driving mode to the second driving mode. That is, the first switching condition for switching the driving mode from the first driving mode to the second driving mode is that the vehicle speed V1 of the other vehicle 21 exceeds the threshold speed.

[0031] Next, the control proceeds to step S4. In step S4, the automatic return possible time setting unit 4 of the driving control device 100 sets the automatic return possible time from the timing when the driving mode of the host vehicle 20 is switched from the first driving mode to the second driving mode as the starting point.

[0032] Next, control proceeds to step S5. In step S5, the remaining time measurement unit 2 of the operation control device 100 starts counting down the remaining time until the automatic return possible time has elapsed at the timing when the operation mode is switched from the first operation mode to the second operation mode.

[0033] Then, the control proceeds to step S6. In step S6, the output unit 3 of the driving control device 100 starts outputting information indicating a countdown of the remaining time until automatic return is possible at the timing when the driving mode is switched from the first driving mode to the second driving mode. That is, from the timing when the driving mode is switched from the first driving mode to the second driving mode, the user interface 16 presents the occupant with a countdown of the remaining time. The processes in steps S3 to S6 are executed at approximately the same timing.

[0034] Next, the control proceeds to step S7. In step S7, the operation control device 100 determines whether or not the automatic return possible time has elapsed since the operation mode was switched from the first operation mode to the second operation mode.

[0035] If the automatic return possible time has not yet elapsed, control proceeds to step S8. In step S8, the driving control device 100 determines whether the vehicle speed V1 of the other vehicle 21 has become equal to or less than the threshold speed. If the vehicle speed V1 of the other vehicle 21 has not become equal to or less than the threshold speed, control returns to before step S7. If the vehicle speed V1 of the other vehicle 21 becomes equal to or less than the threshold speed before the automatic return possible time has elapsed, control proceeds to step S9, and the driving control device 100 switches and returns the driving mode from the second driving mode to the first driving mode. That is, the second switching condition for returning the driving mode from the second driving mode to the first driving mode is that the vehicle speed V1 of the other vehicle 21 becomes equal to or less than the threshold speed.

[0036] On the other hand, if it is determined in step S7 that the automatic return possible time has already elapsed, control proceeds to step S10. In step S10, the driving control device 100 determines whether or not a driving mode switching request has been input by the driver to the input device 15. If there is no driving mode switching request, control ends. If there is a driving mode switching request, control proceeds to step S9, and the driving control device 100 switches the driving mode from the second driving mode to the first driving mode and returns to the original driving mode.

[0037] End To Therefore, the driving control device 100 according to this embodiment sets an automatic return possible time, which is the time during which the driving mode of the vehicle 20 can automatically switch from the second driving mode to the first driving mode and return to the first driving mode, starting from the timing when the driving mode of the vehicle 20 switches from the first driving mode to the second driving mode. 、The driving control device 100 executes a countdown of the remaining time from the current time until the automatic return possible time has elapsed, and outputs information indicating the countdown of the remaining time to the user interface 16 of the vehicle 20. This allows the occupants, including the driver of the vehicle 20, to know the remaining time of the automatic return possible time during which the driving mode can return from the second driving mode to the first driving mode. Furthermore, when the remaining time of the automatic return possible time becomes 0, the occupants can input an instruction to return the driving mode (driving mode switching request) to the input device 15 if they wish to return the driving mode after confirming that the driving mode will not automatically return to the first driving mode thereafter.

[0038] Furthermore, if the driving conditions of the vehicle satisfy the second switching condition before the automatic return possible time has elapsed, the driving control device 100 automatically switches the driving mode from the second driving mode to the first driving mode. This allows the driving control device 100 to automatically return the driving mode from the second driving mode to the first driving mode when the driving conditions of the vehicle become suitable for the first driving mode.

[0039] In addition, the first switching condition for the driving control device 100 to switch the driving mode from the first driving mode to the second driving mode is that the vehicle speed V1 of the other vehicle 21 in front of the host vehicle 20 exceeds a predetermined threshold speed. In addition, the second switching condition for the driving control device 100 to switch the driving mode from the second driving mode to the first driving mode and return to the first driving mode is that the vehicle speed V1 of the other vehicle 21 becomes equal to or lower than the threshold speed. This allows the driver to predict in advance that the driving mode will automatically return to the first driving mode following the other vehicle 21 if the other vehicle 21 is likely to decelerate to the threshold vehicle speed or lower before the remaining time of the automatic return possible time, which is counted down and displayed, reaches 0. On the other hand, when the remaining time of the automatic return possible time reaches 0, the driver can confirm that the driving mode will not automatically return to the first driving mode from then on, even if the vehicle speed V1 of the other vehicle 21 becomes equal to or lower than the threshold speed.

[0040] In addition, the driving control device 100 starts outputting information indicating a countdown of the remaining time at the timing when the driving mode is switched from the first driving mode to the second driving mode. This allows the occupants of the vehicle 20 to sequentially check the remaining time of the automatic return possible time by the countdown starting from the timing when the driving mode is switched from the first driving mode to the second driving mode.

[0041] In the flowchart of Fig. 3, if the vehicle speed V1 of the other vehicle 21 becomes equal to or lower than the threshold speed, the driving mode can be returned to the first driving mode before the automatic return possible time has elapsed, but this is not limited thereto, and the driving mode may be set to return when the automatic return possible time has elapsed. Fig. 4 shows the procedure of the driving control method in which the second switching condition is that the vehicle speed V1 of the other vehicle 21 becomes equal to or lower than the threshold speed, and the driving mode is returned when the automatic return possible time has elapsed.

[0042] In such a case, as shown in FIG. 4, in step S5, the remaining time measurement unit 2 of the operation control device 100 starts counting down the remaining time for the automatic recovery time. did Thereafter, control proceeds to step S7. In step S7, the operation control device 100 determines whether or not the automatic return possible time has elapsed since the operation mode was switched from the first operation mode to the second operation mode.

[0043] If it is determined in step S7 that the automatic return possible time has not yet elapsed, control proceeds to step S8, similar to Fig. 3. In step S8, the driving control device 100 determines whether or not the vehicle speed V1 of the other vehicle 21 has become equal to or less than the threshold speed. If it is determined in step S8 that the vehicle speed V1 of the other vehicle 21 has become equal to or less than the threshold speed before the automatic return possible time has elapsed, control proceeds to step S11.

[0044] In step S11, the driving control device 100 starts outputting information indicating a countdown of the remaining automatic return possible time from the current time when the vehicle speed V1 of the other vehicle 21 ahead of the host vehicle 20 becomes equal to or less than the threshold speed. Then, in step S9, the driving control device 100 switches the driving mode from the second driving mode to the first driving mode when the automatic return possible time has elapsed, and returns the driving mode to the first driving mode.

[0045] In this way, when the driving control device 100 automatically switches and returns the driving mode when the automatic return possible time has elapsed, the driving control device 100 may start outputting information indicating a countdown of the remaining time when the vehicle speed V1 of the other vehicle 21 becomes equal to or lower than the threshold speed, that is, when the driving situation of the host vehicle 20 satisfies the second switching condition. This allows the occupants of the host vehicle 20 to know the remaining time of the automatic return possible time when it is certain that the driving mode will automatically return. In other words, while it is not certain whether the driving mode will automatically return or not, the countdown of the remaining time is not displayed on the user interface 16, so the driver can concentrate on driving. In this embodiment, the "timing at which the driving conditions of the host vehicle 20 satisfy the second switching condition" does not necessarily have to be exactly the same time as the vehicle speed V1 of the other vehicle 21 becomes below the threshold speed, but may be "immediately after the vehicle speed V1 of the other vehicle 21 becomes below the threshold speed."

[0046] Note that even if the vehicle speed V1 of the other vehicle 21 becomes equal to or lower than the threshold speed before the automatic return possible time has elapsed, if the vehicle speed V1 of the other vehicle 21 exceeds the threshold speed again before the automatic return possible time has elapsed, the driving control device 100 does not return the driving mode from the second driving mode to the first driving mode. In this case, when the vehicle speed V1 of the other vehicle 21 exceeds the threshold speed again, the display of the remaining time of the automatic return possible time may be erased from the information displayed on the user interface 16, or information indicating that the driving mode will not be automatically returned may be displayed on the user interface 16.

[0047] Second Embodiment The second embodiment will be described with reference to FIGS. Fig. 6 is a flowchart showing the procedure of a driving control method using the driving control device 100 when the host vehicle 20 changes lanes from the first lane 31 to the second lane 32 as shown in Fig. 5. In the following explanation, the same reference numerals as those in Figs. 3 and 4 indicate the same or similar steps, and therefore detailed explanations will be omitted.

[0048] As shown in FIG. 6, if it is determined in step S1 that the host vehicle 20 is controlled in the first driving mode, the control proceeds to step S22. In step S22, the driving control device 100 determines whether the host vehicle 20 executes a lane change, that is, whether the host vehicle 20 starts a lane change operation. Specifically, the driving control device 100 determines that the host vehicle 20 starts a lane change operation when the driver grips the steering wheel and performs a manual operation for lane change. In addition, the driving control device 100 may determine that the host vehicle 20 starts a lane change operation when the driver operates a button provided on the input device 15 to input an instruction to execute a lane change. In addition, the driving control device 100 may refer to map information acquired from the map database 14 and determine whether the host vehicle 20 executes a lane change based on a route from the current position of the host vehicle 20 detected by the host vehicle position detection device 13 to the destination.

[0049] If it is determined in step S22 that the host vehicle 20 does not execute lane change, the control ends. On the other hand, if it is determined that the host vehicle 20 starts a lane change operation, the control proceeds to step S3, and the driving control device 100 switches the driving mode from the first driving mode to the second driving mode. As a result, the host vehicle 20 executes a lane change operation toward the second lane 32 in the second driving mode. That is, the first switching condition for switching the driving mode from the first driving mode to the second driving mode is that the host vehicle 20 traveling on the first lane 31 starts a lane change operation toward the second lane 32 different from the first lane 31. Note that the driving control device 100 may notify the occupant of the switching from the first driving mode to the second driving mode and notify the driver to grip the steering wheel before switching the driving mode from the first driving mode to the second driving mode. Also, the driving control device 100 may switch the driving mode from the first driving mode to the second driving mode after detecting that the driver has gripped the steering wheel.

[0050] Next, in step S4, the operation control device 100 sets the automatic return time, and in step S5, starts counting down the remaining automatic return time. Furthermore, in step S6, the output unit 3 of the operation control device 100 starts outputting information indicating the countdown of the remaining automatic return time at the timing when the operation mode is switched from the first operation mode to the second operation mode. Next, control proceeds to step S7, where the operation control device 100 determines whether the automatic return time has elapsed since the operation mode was switched from the first operation mode to the second operation mode.

[0051] If the automatic return possible time has not yet elapsed, control proceeds to step S28. In step S28, the driving control device 100 judges whether the lane change operation of the host vehicle 20 has been completed. Specifically, after the lane change operation in which the lateral position has been changed by steering, if the steering control amount (steering angle) of the host vehicle 20 by the driver is equal to or less than a predetermined amount (a steering angle that can be determined as going straight) or if the steering control amount decreases after the steering direction is reversed, the driving control device 100 judges that the lane change operation of the host vehicle 20 has been completed. Also, if it is determined that the host vehicle 20 after the lane change operation is traveling along the second lane 32 based on the information acquired from the host vehicle position detection device 13 and the map database 14, the driving control device 100 judges that the lane change operation of the host vehicle 20 has been completed. If the lane change operation of the host vehicle 20 has not been completed, control returns to before step S7. If the lane change operation of the host vehicle 20 is completed before the automatic return possible time has elapsed, control proceeds to step S9, and the driving control device 100 switches the driving mode from the second driving mode to the first driving mode to return. That is, the second switching condition for switching the driving mode from the second driving mode to the first driving mode to return is that the host vehicle 20 moves to the second lane 32 and completes the lane change operation.

[0052] From the above, the driving control device 100 according to this embodiment sets the first switching condition for switching the driving mode from the first driving mode to the second driving mode as the host vehicle 20 traveling on the first lane 31 starting a lane change operation toward the second lane 32 different from the first lane 31. In addition, the driving control device 100 sets the second switching condition for switching the driving mode from the second driving mode to the first driving mode and returning as the host vehicle 20 moving to the second lane 32 and completing the lane change operation. As a result, even when the host vehicle 20 executes a lane change with the autonomous driving level temporarily lowered, the occupant of the host vehicle 20 can grasp the remaining time of the automatic return possible time during which the driving mode can be automatically returned. Therefore, the driver can drive the host vehicle 20 so as to complete the lane change operation before the automatic return possible time has elapsed.

[0053] In the flowchart of Fig. 6, the driving mode can be returned to the first driving mode before the automatic return possible time has elapsed if the lane change operation of the vehicle 20 is completed, but this is not limited thereto, and the driving mode may be set to return when the automatic return possible time has elapsed after the lane change. Fig. 4 shows the procedure of the driving control method in the case where the second switching condition is that the vehicle 20 completes the lane change operation and the driving mode is returned when the automatic return possible time has elapsed.

[0054] 7, in step S5, the remaining time measurement unit 2 of the operation control device 100 starts counting down the remaining automatic return time, and then control proceeds to step S7. In step S7, the operation control device 100 determines whether the automatic return time has elapsed since the operation mode was switched from the first operation mode to the second operation mode.

[0055] If it is determined in step S7 that the automatic return possible time has not yet elapsed, control proceeds to step S28, similar to Fig. 6. In step S28, the driving control device 100 determines whether or not the host vehicle 20 has completed the lane change operation. If it is determined in step S28 that the host vehicle 20 has completed the lane change operation before the automatic return possible time has elapsed, control proceeds to step S11.

[0056] In step S11, the driving control device 100 starts outputting information indicating a countdown of the remaining automatic return time from the current time when the vehicle 20 completes a lane change operation. Then, in step S9, the driving control device 100 returns the driving mode from the second driving mode to the first driving mode when the automatic return time has elapsed.

[0057] In this way, when the driving control device 100 automatically returns the driving mode when the automatic return possible time has elapsed, the driving control device 100 may start outputting the remaining time when the host vehicle 20 completes the lane change operation, that is, when the driving situation of the host vehicle 20 satisfies the second switching condition. This allows the driver of the host vehicle 20 to know the remaining time of the automatic return possible time when the driving for lane change in the second driving mode is completed. In other words, while the lane change operation in the second driving mode is being performed, the countdown of the remaining time is not displayed on the user interface 16, so the driver can concentrate on driving. In this embodiment, the "timing at which the driving conditions of the host vehicle 20 satisfy the second switching condition" does not necessarily have to be exactly the same time as the host vehicle 20 completes the lane change, but may be "immediately after the host vehicle 20 completes the lane change."

[0058] Furthermore, without being limited thereto, the driving control device 100 may start outputting the remaining time to the user interface 16 while the host vehicle 20 is executing a lane change operation.

[0059] The first switching condition and the second switching condition are not limited to those in the first and second embodiments. For example, the driving control device 100 may set the first switching condition to be that no clear white line is displayed on the driving route, or that the map database 14 does not have high-precision map information for the route. The driving control device 100 may set the second switching condition to be that a clear white line is displayed on the driving route, or that the map database 14 has high-precision map information for the route.

[0060] The driving control device 100 may also set a first driving mode section in which the vehicle should travel in the first driving mode and a second driving mode section in which the vehicle should travel in the second driving mode, in the planned driving route of the vehicle 20. In this case, the driving control device 100 may set the first switching condition to be that the position of the vehicle 20 has moved from the first driving mode section to the second driving mode section, and the second switching condition to be that the position of the vehicle 20 has moved from the second driving mode section to the first driving mode section. [Explanation of symbols]

[0061] 100...Operation control device 101…Processor 1...Operation mode control unit 2. Remaining time measurement section 3. Output section 4. Automatic recovery time setting section 16...User Interface 20…Own vehicle 21...Other vehicles 31…1st lane 32…2nd lane

Claims

1. A driving control method using a processor to control driving of a host vehicle using at least one of two driving modes including a first driving mode and a second driving mode having a driving assistance level lower than that of the first driving mode, The processor, determining whether or not a driving situation of the host vehicle traveling in the first driving mode satisfies a predefined first switching condition; When the driving state of the host vehicle satisfies the first switching condition, the driving mode is switched from the first driving mode to the second driving mode; set an automatic return possible time, which is a time during which the driving mode of the host vehicle can be automatically switched from the second driving mode to the first driving mode, starting from a timing when the driving mode of the host vehicle is switched from the first driving mode to the second driving mode; After the driving mode is switched from the first driving mode to the second driving mode, before the automatic return possible time has elapsed, determining whether or not a driving situation of the host vehicle satisfies a predefined second switching condition; When the driving state of the host vehicle satisfies the second switching condition before the automatic return possible time has elapsed, the driving mode is automatically switched from the second driving mode to the first driving mode; At a timing when the operation mode is switched from the first operation mode to the second operation mode, a countdown of the remaining time from the current time to the time when the automatic return possible time has elapsed is started, outputting information indicating the countdown of the remaining time to a user interface of the host vehicle; an operation control method for automatically switching the operation mode from the second operation mode to the first operation mode at a timing when the automatic return possible time has elapsed;

2. A driving control method using a processor to control driving of a host vehicle using at least one of two driving modes including a first driving mode and a second driving mode having a driving assistance level lower than that of the first driving mode, The processor, determining whether or not a driving situation of the host vehicle traveling in the first driving mode satisfies a predefined first switching condition; When the driving state of the host vehicle satisfies the first switching condition, the driving mode is switched from the first driving mode to the second driving mode; set an automatic return possible time, which is a time during which the driving mode of the host vehicle can be automatically switched from the second driving mode to the first driving mode, starting from a timing when the driving mode of the host vehicle is switched from the first driving mode to the second driving mode; Counting down the remaining time from the current time to the time when the automatic recovery possible time has elapsed, outputting information indicating the countdown of the remaining time to a user interface of the host vehicle; After the driving mode is switched from the first driving mode to the second driving mode, before the automatic return possible time has elapsed, determining whether or not a driving situation of the host vehicle satisfies a predefined second switching condition; When the driving situation of the host vehicle satisfies the second switching condition before the automatic return possible time has elapsed, start outputting information indicating a countdown of the remaining time at the timing when the driving situation of the host vehicle satisfies the second switching condition, an operation control method for automatically switching the operation mode from the second operation mode to the first operation mode at a timing when the automatic return possible time has elapsed;

3. A driving control method using a processor to control driving of a host vehicle using at least one of two driving modes including a first driving mode and a second driving mode having a driving assistance level lower than that of the first driving mode, The processor, Determine whether or not a driving situation of the host vehicle traveling in the first driving mode satisfies a first switching condition that is a predefined condition that a vehicle speed of another vehicle ahead of the host vehicle exceeds a predetermined threshold speed; When the driving state of the host vehicle satisfies the first switching condition, the driving mode is switched from the first driving mode to the second driving mode; set an automatic return possible time, which is a time during which the driving mode of the host vehicle can be automatically switched from the second driving mode to the first driving mode, starting from a timing when the driving mode of the host vehicle is switched from the first driving mode to the second driving mode; Counting down the remaining time from the current time to the time when the automatic recovery possible time has elapsed, outputting information indicating the countdown of the remaining time to a user interface of the host vehicle; After the driving mode is switched from the first driving mode to the second driving mode, before the automatic return possible time has elapsed, determining whether or not a driving situation of the host vehicle satisfies a predefined second switching condition, in which a vehicle speed of another vehicle ahead of the host vehicle becomes equal to or lower than the threshold speed; A driving control method for automatically switching the driving mode from the second driving mode to the first driving mode when the driving situation of the vehicle satisfies the second switching condition before the automatic return possible time has elapsed.

4. The first switching condition is that the host vehicle traveling on a first lane starts a lane change operation toward a second lane different from the first lane, The driving control method according to any one of claims 1 to 3, wherein the second switching condition is that the host vehicle moves into the second lane and completes a lane change operation.

5. The operation control method according to claim 1 or 3, wherein the processor starts outputting information indicating a countdown of the remaining time at a timing when the operation mode is switched from the first operation mode to the second operation mode.

6. A driving control device that controls driving of a vehicle using at least one of two driving modes including a first driving mode and a second driving mode having a driving assistance level lower than that of the first driving mode, a driving mode control unit that determines whether a driving situation of the host vehicle traveling in the first driving mode satisfies a predefined first switching condition, and switches the driving mode from the first driving mode to the second driving mode when the driving situation of the host vehicle satisfies the first switching condition; an automatic return possible time setting unit that sets an automatic return possible time, which is a time during which the driving mode of the host vehicle can automatically switch from the second driving mode to the first driving mode, starting from a timing when the driving mode of the host vehicle is switched from the first driving mode to the second driving mode; a remaining time measuring unit that executes a countdown of the remaining time from the current time to the time when the automatic return possible time has elapsed; an output unit that outputs information indicating the countdown of the remaining time to a user interface of the host vehicle; the driving mode control unit determines whether or not a driving situation of the host vehicle satisfies a predefined second switching condition before the automatic return possible time has elapsed after the driving mode has been switched from the first driving mode to the second driving mode, and if the driving situation of the host vehicle satisfies the second switching condition before the automatic return possible time has elapsed, automatically switches the driving mode from the second driving mode to the first driving mode at a timing when the automatic return possible time has elapsed; the remaining time measurement unit, at a timing when the operation mode is switched from the first operation mode to the second operation mode, starts a countdown of a remaining time from a current time to a timing when the automatic return possible time has elapsed; the output unit outputs information indicating the countdown of the remaining time to a user interface of the host vehicle; The operation mode control unit is an operation control device that automatically switches the operation mode from the second operation mode to the first operation mode when the automatic return possible time has elapsed.

7. A driving control device that controls driving of a vehicle using at least one of two driving modes including a first driving mode and a second driving mode having a driving assistance level lower than that of the first driving mode, a driving mode control unit that determines whether a driving situation of the host vehicle traveling in the first driving mode satisfies a predefined first switching condition, and switches the driving mode from the first driving mode to the second driving mode when the driving situation of the host vehicle satisfies the first switching condition; an automatic return possible time setting unit that sets an automatic return possible time, which is a time during which the driving mode of the host vehicle can automatically switch from the second driving mode to the first driving mode, starting from a timing when the driving mode of the host vehicle is switched from the first driving mode to the second driving mode; a remaining time measuring unit that executes a countdown of the remaining time from the current time to the time when the automatic return possible time has elapsed; an output unit that outputs information indicating the countdown of the remaining time to a user interface of the host vehicle; the driving mode control unit determines whether or not a driving situation of the host vehicle satisfies a predefined second switching condition before the automatic return possible time elapses after the driving mode is switched from the first driving mode to the second driving mode, When the driving situation of the host vehicle satisfies the second switching condition before the automatic return possible time has elapsed, the output unit starts outputting information indicating a countdown of the remaining time at a timing when the driving situation of the host vehicle satisfies the second switching condition, The operation mode control unit automatically switches the operation mode from the second operation mode to the first operation mode when the automatic return possible time has elapsed.

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