Vehicle driving support device

Abstract

To suppress sudden acceleration even if a driver erroneously steps on an accelerator pedal during a standby time in shifting an automatic driving mode to a manual driving mode due to a failure of a forward recognition sensor for acquiring travel environmental information in front of an own vehicle.SOLUTION: If a failure of a forward recognition sensor 21 is detected during traveling in an automatic driving mode (S16), a limited accelerator opening degree table is selected (S17). The limited accelerator opening degree table suppresses sudden acceleration even if a driver erroneously steps on an accelerator pedal because an output of a driving source is set in a limited characteristic to an increase in an access opening degree θacc.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a vehicle driving assistance device that suppresses sudden acceleration even if the driver accidentally presses the accelerator pedal when transitioning from autonomous driving to manual driving due to a failure in a driving environment information acquisition unit while driving in autonomous driving mode. [Background technology]

[0002] In recent years, various driving assistance devices have been developed for vehicles such as automobiles that have an automatic driving function that allows the vehicle to run without the driver's operation. During automatic driving, the driver basically does not need to hold the steering wheel or constantly check the road ahead, and is allowed to perform secondary tasks such as reading a book or operating a mobile device.

[0003] However, if sensors that detect parameters related to autonomous driving break down during autonomous driving and the driving assistance device determines that it is difficult to continue autonomous driving, it is necessary to have the driver take over driving. In that case, if the driving assistance device suddenly transitions from autonomous driving to manual driving, the driver will become flustered. Therefore, as disclosed in Patent Document 1 (JP Patent Publication 2020-131844), for example, the driving assistance device first requests the driver to take over to transition to manual driving, and waits for a predetermined time.

[0004] If the driver responds to a request to take over during the waiting time and grips the steering wheel, the system transitions from automatic to manual driving. If the driver does not respond to the request to take over during the waiting time, the system executes automatic evacuation control to evacuate the vehicle to a safe location such as the shoulder of the road. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-131844 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, in conventional driving assistance devices, when driving assistance controls such as adaptive cruise control (ACC) and active lane keep (ALK) control are being executed, the driver D is required to always grip the steering wheel H and maintain a driving posture with his / her eyes fixed on the road ahead, even if his / her feet are directly placed on the floor mat, as shown in FIG. 6(a).

[0007] In contrast, during autonomous driving (so-called fully autonomous driving), driver D is permitted to have a second task, so as shown in Figure 6(b), driver D can take his / her hands off the steering wheel H and sit in the driver's seat in a relaxed position.

[0008] In such a relaxed posture, movements tend to become sluggish, and when the driving assistance device notifies the driver D that it will transition to manual driving, the driver becomes anxious that if he does not react immediately, automatic evacuation control will be executed, and he frantically tries to grasp the steering wheel H.

[0009] At that time, if the driver unconsciously depresses the accelerator pedal, the driving assistance system may erroneously determine that the vehicle is overdriving, resulting in sudden acceleration unintended by the driver D. In particular, if the cause of the transition from autonomous driving to manual driving is a failure in the driving environment information acquisition unit that acquires driving environment information ahead of the vehicle, the driving assistance system may be in a state where it is difficult to recognize the preceding vehicle. Therefore, the sudden acceleration of the vehicle may panic the driver.

[0010] In consideration of the above circumstances, the present invention aims to provide a vehicle driving assistance device that prevents the driver from panicking by suppressing sudden acceleration even if the driver accidentally presses the accelerator pedal when transitioning from autonomous driving to manual driving due to a failure of a driving environment information acquisition unit that acquires information about the driving environment in front of the vehicle. [Means for solving the problem]

[0011] The present invention relates to a driving assistance device for a vehicle including a driving environment information acquisition unit that acquires driving environment information ahead of the vehicle, a driving state information acquisition unit that acquires driving state information of the vehicle, and a driving control unit that executes automatic driving control of the vehicle based on the driving environment information acquired by the driving environment information acquisition unit and the driving state information detected by the driving state information acquisition unit. The device further includes a failure detection unit that detects failures in the driving environment information acquisition unit and the driving state information acquisition unit, and a driving control unit that controls the driving control unit to control the vehicle. The above The vehicle further includes a handover request processing unit that executes a handover request process to switch to manual driving when the failure detection unit detects a failure in at least one of the driving environment information acquisition unit and the driving state information acquisition unit during driving under automatic driving control, and the handover request processing unit measures a waiting time from when the failure detection unit detects a failure to when the vehicle transitions to the manual driving. Together , during said waiting time Lucky By transferee When the accelerator pedal operation is detected, the automatic driving control is temporarily suspended and the driver's The output of the drive source relative to the accelerator operation amount is The output should be smaller than that during manual operation. Output Limit Department Equipped with. Effect of the Invention

[0012] According to the present invention, if the failure detection unit detects a failure in the driving environment information acquisition unit during automatic driving, the output of the drive source relative to the accelerator operation amount by the driver is limited during the waiting time until transition to manual driving, so that even if the driver accidentally depresses the accelerator pedal during the waiting time, sudden acceleration is suppressed. Therefore, the driver does not panic. [Brief description of the drawings]

[0013] [Figure 1] Overall configuration of the driving support device [Diagram 2] Flowchart showing operation mode transfer control routine [Diagram 3] Flowchart showing takeover request processing subroutine [Figure 4](a) is a conceptual diagram showing an accelerator opening table based on torque control, and (b) is a conceptual diagram showing an accelerator opening table based on acceleration control. [Diagram 5] A schematic diagram showing the recognition area of ​​a sensor that acquires driving environment information around the vehicle. [Figure 6] (a) is a side view showing the driver's posture in manual driving mode, and (b) is a side view showing the driver's posture in automatic driving mode. [Figure 7] FIG. 1A is a time chart showing an example of control when the driving mode is transitioned to a manual driving mode due to a failure of a forward recognition sensor, and FIG. 1B is a time chart showing an example of control when the driving mode is transitioned to a manual driving mode due to a failure of a sensor other than the forward recognition sensor. [Figure 8] Time chart showing an example of control when transitioning the operation mode to MRM mode DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Reference symbol M in Fig. 5 indicates a host vehicle traveling in a driving lane. Reference symbol P indicates a vehicle traveling in an adjacent lane (overtaking lane), and reference symbol F indicates a preceding vehicle traveling immediately before the host vehicle M.

[0015] A driving assistance device 1 shown in Fig. 1 is mounted on the vehicle M. The driving assistance device 1 includes a driving assistance control unit 11 as a driving control unit. The driving assistance control unit 11 includes a microcomputer including a CPU, a ROM, a RAM, and the like, and peripheral devices thereof, and the ROM stores fixed data such as a control program for implementing operations set for each system and data tables.

[0016] The driving assistance control unit 11 sets a driving mode and performs corresponding driving assistance. The driving assistance control unit 11 has a manual driving mode, an automatic driving mode, and an MRM (Minimum Risk Maneuver) mode as driving modes. Here, the automatic driving mode and the manual driving mode are driving modes that the driver can select at will.

[0017] Even if the driver D selects the manual driving mode, as long as the various sensors are operating normally, the driving assistance control unit 11 can execute various driving assistance controls such as the well-known Advanced Emergency Braking (AEB) control, ACC control, ALK control, and LDP control.

[0018] In the autonomous driving mode, the vehicle M is driven autonomously in an area where autonomous driving is possible, along a preset target route by map matching on a road map in the road map database 23b based on the vehicle position information acquired by the GNSS sensor 23a of the map locator unit 23, which will be described later. In this case, the vehicle M is driven hands-free, and the driver is allowed to perform a second task.

[0019] In addition, the MRM mode automatically stops the vehicle M in a safe place such as the shoulder of the road when the driving assistance control unit 11 determines that driving in the automatic driving mode is difficult and determines that the driving mode cannot be transferred from the automatic driving mode to the manual driving mode.

[0020] Sensors (hereinafter collectively referred to as "autonomous driving sensors") are connected to the input side of the driving assistance control unit 11 as driving state information acquisition units that acquire driving state information (including position and direction) of the vehicle M and are required when executing the autonomous driving mode. In this embodiment, the autonomous driving sensors include a forward recognition sensor 21 as a driving environment information acquisition unit, a map locator unit 23, an autonomous driving sensor 24, a vehicle speed sensor 25 that detects the vehicle speed (vehicle speed), an accelerator opening sensor 26 that detects the accelerator pedal operation amount (accelerator opening θacc), a left front side sensor 27, a right front side sensor 28, a left rear side sensor 29, and a right rear side sensor 30. In addition, a driving intention detection sensor 31 is provided to confirm the driver's intention when the driving mode is shifted from the autonomous driving mode to the manual driving mode due to a failure (including a temporary failure) of the autonomous driving sensor.

[0021] Here, the forward recognition sensor 21 is an image sensor, and has a stereo camera consisting of a main camera 21a and a sub camera 21b, and an image processing unit (IPU) 22. The cameras 21a and 21b are installed horizontally at equal intervals on the left and right from the center in the vehicle width direction at a position close to the windshield, for example, above the rearview mirror at the front of the vehicle. The forward recognition sensor 21 performs predetermined image processing on the driving environment information of a predetermined imaging area 21A (see FIG. 5) in front of the vehicle, which is captured and acquired by the cameras 21a and 21b, in the IPU 22, and then transmits it to the driving assistance control unit 11.

[0022] The map locator unit 23 includes a GNSS (Global Navigation Satellite System) sensor 23a and a road map database 23b. The GNSS sensor 23a receives positioning signals transmitted from a plurality of positioning satellites to acquire the position coordinates of the vehicle. The road map database 23b is a large-capacity storage medium such as an HDD, and stores well-known road map information. The stored road map information includes information required for performing automatic driving, such as road type (general road, main road, expressway, etc.), road shape, road direction, number of lanes, lane width, etc. The driving assistance control unit 11 performs map matching of the position coordinates (latitude, longitude, altitude) acquired by the GNSS sensor 23a on the road map information stored in the road map database 23b, and estimates the vehicle's position (current position) on the road map, and which lane the vehicle is traveling on if multiple lanes are being traveled on.

[0023] The autonomous driving sensor 24 detects the traveling direction (orientation) of the host vehicle M to enable autonomous driving in an environment where the reception sensitivity from the GNSS satellite is low and the positioning signal cannot be effectively received, such as driving inside a tunnel, and is composed of a yaw rate sensor, a longitudinal acceleration sensor, etc. That is, the driving assistance control unit 11 determines the travel distance and direction of the host vehicle M based on the vehicle speed detected by the vehicle speed sensor 25, the yaw rate (yaw angular velocity) detected by the yaw rate sensor included in the autonomous driving sensor 24, and the longitudinal acceleration detected by the longitudinal acceleration sensor, and estimates the current position by map matching on the road map database 23b.

[0024] Each of the side sensors 27-30 is composed of a millimeter wave radar, a microwave radar, a LiDAR (Light Detection and Ranging), etc., and receives a reflected wave from a target to detect the distance and direction from the vehicle M to the target. As shown in FIG. 5, the left and right front side sensors 27, 28 are arranged, for example, on the left and right ridges of a front bumper, while the left and right rear side sensors 29, 30 are arranged, for example, on the left and right ridges of a rear bumper. The left and right front side sensors 27, 28 scan areas (scanning areas) 27A, 28A diagonally from the left and right front to the sides of the vehicle M in a fan shape. On the other hand, the left and right rear side sensors 29, 30 scan areas (scanning areas) 29A, 30A that cannot be scanned by the front side sensors 27, 28, in a fan shape, from the rear to the left and right of the vehicle M. Then, targets represented by an adjacent vehicle P traveling in an adjacent lane are detected.

[0025] Incidentally, it is possible to some extent for the left and right front side sensors 27, 28 to detect obstacles including the preceding vehicle F ahead of the host vehicle M. Therefore, for example, if the cameras 21a, 21b of the forward recognition sensor 21 fail while driving in the autonomous driving mode, it is possible for the left and right front side sensors 27, 28 to detect obstacles instead, although with lower accuracy. Furthermore, it is also possible to continue autonomous driving to some extent by map matching the position coordinates of the host vehicle M acquired by the GNSS sensor 23a of the map locator unit 23 on the road map information stored in the road map database 23b.

[0026] In addition, the driving intention detection sensor 31 checks whether the driver D intends to drive the vehicle himself / herself when transitioning the driving mode from the automatic driving mode to the manual driving mode, and is arranged separately from the automatic driving sensor described above.

[0027] 6(a) and (b), the driving intention detection sensor 31 includes a driver monitor system (DMS) 31A as an orientation determination unit that monitors the face position and expression of the driver D, a steering wheel touch sensor 31B disposed on the steering wheel H, and a steering torque sensor 31C that detects steering torque from the twist of the steering shaft 32. The steering wheel touch sensor 31B or the steering torque sensor 31C corresponds to the grip detection unit of the present invention.

[0028] In this embodiment, the driving intention detection sensor 31 is composed of the DMS 31A and the steering wheel touch sensor 31B or the steering torque sensor 31C.

[0029] The driving assistance control unit 11 checks whether the driver's face is facing forward based on the image captured by the DMS 31A. Furthermore, the driving assistance control unit 11 checks whether the driver D is gripping the steering wheel H based on the output from the steering wheel touch sensor 31B or the steering torque sensor 31C.

[0030] Then, when the driving assistance control unit 11 determines that the driver is facing forward based on the image captured by the DMS 31A and determines that the driver D is gripping the steering wheel H based on the output of the steering wheel touch sensor 31B or the steering torque sensor 31C, it determines that the driver has the intention to drive. When the driving assistance control unit 11 determines that the driver D is not facing forward based on the image captured by the DMS 31A or determines that the driver D is not gripping the steering wheel H based on the output of the steering wheel touch sensor 31B or the steering torque sensor 31C, it determines that the intention to drive cannot be confirmed.

[0031] Also, a drive control actuator 33 and an alarm device 34 are connected to the output side of the driving assistance control unit 11. The drive control actuator 33 is a general term for a power actuator, an electric power steering (EPS) actuator, a brake actuator, etc., which support the driving state of the host vehicle M. Here, the power actuator controls the output of a drive source such as an engine or an electric motor. The EPS actuator controls the drive of the EPS motor. Also, the brake actuator adjusts the brake hydraulic pressure supplied to the brake wheel cylinders provided on each wheel. Furthermore, the alarm device 34 notifies the driver of a request to take over driving through a buzzer sound, voice, monitor display, etc., when the driving mode is transitioned to the manual driving mode.

[0032] The driving assistance control unit 11 recognizes obstacles ahead, including the preceding vehicle F to be followed by the host vehicle M, based on driving environment information from the forward recognition sensor 21, and executes driving assistance control such as ACC control and AEB control. In addition, when the host vehicle M is driven in the autonomous driving mode, the driving assistance control unit 11 constantly monitors the output of the autonomous driving sensor. If a failure (including a temporary malfunction) of the autonomous driving sensor is detected, the driving assistance control unit 11 notifies the driver D of the failure and transitions the driving mode from the autonomous driving mode to the manual driving mode.

[0033] However, if the driving mode is suddenly changed from the automatic driving mode to the manual driving mode, the driver will be flustered, so a handover waiting time Co is set, the driver D is made to take over driving within the handover waiting time Co, and then the driving mode is changed to the manual driving mode. Therefore, the driving assistance control unit 11 continues automatic driving for at most the handover waiting time Co, although with restrictions such as setting an upper limit on the vehicle speed.

[0034] The drive mode changeover when the drive assistance control unit 11 is in the automatic drive mode is performed according to a drive mode changeover control routine shown in FIG.

[0035] This routine is started at every predetermined calculation cycle, and first, in step S1, it is checked whether or not the automatic driving mode is selected as the driving mode of the host vehicle M. If the automatic driving mode is not selected, the routine is exited and the system waits until the automatic driving mode is selected. If the automatic driving mode is selected, the system proceeds to step S2.

[0036] In step S2, the outputs of sensors (autonomous driving sensors) that detect parameters required for executing the autonomous driving mode are read. The autonomous driving sensors have been described above, so a detailed description is omitted here. Next, the process proceeds to step S3, where the accelerator opening (accelerator operation amount) θacc, which is the output of the accelerator opening sensor 26, is read.

[0037] Next, the process proceeds to step S4, where it is determined whether or not there is an acceleration request, i.e., whether or not the accelerator pedal is depressed, based on the accelerator opening θacc detected in step S2. If the accelerator pedal is depressed, it is determined that there is an acceleration request, and the process branches to step S5. If it is determined that the accelerator opening θacc is approximately 0 [deg], that is, the accelerator pedal is released (not depressed), the process proceeds to step S6.

[0038] In step S5, automatic driving is temporarily suspended and acceleration control is executed. This acceleration control is performed in an acceleration control subroutine (not shown). In this acceleration control subroutine, a target vehicle speed is set based on the accelerator opening θacc detected by the accelerator opening sensor 26, an acceleration is set to make the host vehicle speed reach this target vehicle speed, and feedback control is performed so that the host vehicle speed reaches the target vehicle speed. Then, when the driver D releases the accelerator pedal and the accelerator opening θacc detected by the accelerator opening sensor 26 falls below a predetermined opening, the subroutine is exited and step S 9 Proceed to.

[0039] When the process proceeds to step S6, it is checked whether or not there is a failure (including disconnection) based on the output values ​​of the autonomous driving sensors read in step S2. If an output abnormality is detected from any of the autonomous driving sensors, it is determined to be a failure and the process proceeds to step S7. If the output values ​​of all the autonomous driving sensors are normal, the process jumps to step S9. The process in step S6 corresponds to the failure detection unit of the present invention.

[0040] In step S7, the notification device 34 is driven to notify the driver D that the driving mode will be transitioned from the automatic driving mode to the manual driving mode, and the process proceeds to step S8. The notification device 34 notifies the driver D of the transition to the manual driving mode by a buzzer sound, voice, or monitor display. In this case, the notification device 34 may notify the driver D of the transition to the manual driving mode by flashing an indicator lamp that indicates that the vehicle is in automatic driving and is disposed on the instrument panel, or by switching the indicator lamp to a red display to call attention.

[0041] When the process proceeds to step S8, a handover request process is executed to transition the operation mode to the manual operation mode, and the routine ends. When the process proceeds from step S5 or step S6 to step S9, the automatic operation mode is continued (resuming from step S5), and the routine ends.

[0042] The takeover request process in step S8 is executed according to a takeover request process subroutine shown in Fig. 3. The process in this subroutine corresponds to the takeover request processing section of the present invention.

[0043] In this subroutine, first, in step S11, the output value of the driving intention detection sensor 31 is read. As described above, in this embodiment, the driving intention detection sensor 31 is a combination of the DMS 31A and the steering wheel touch sensor 31B or the steering torque sensor 31C.

[0044] Next, the process proceeds to step S12, where it is determined whether or not the driver D intends to take over driving of the vehicle M, based on the output value from the driving intention detection sensor 31. If the driving assistance control unit 11 determines that the driver is facing forward based on the image captured by the DMS 31A, and the steering wheel touch sensor 31B is ON, or the steering torque sensor 31C detects a weak steering torque generated when the driver D grips the steering wheel H, it determines that the driver D intends to take over driving.

[0045] In addition, the time during which the steering wheel touch sensor 31B is ON or the steering torque sensor 31C detects a weak steering torque generated when the driver D grips the steering wheel H may be counted, and if the count value is equal to or greater than a predetermined value (predetermined time), it may be determined that the driver D intends to take over driving.

[0046] In addition, if the driving assistance control unit 11 determines based on the image captured by the DMS 31A that the driver is not facing forward, or if the steering wheel touch sensor 31B is OFF, or if no steering torque is detected from the steering torque sensor 31C, it determines that it is unable to confirm the intention of the driver D to take over driving.

[0047] Then, in step S12, if it is determined that the driver D has the intention to take over driving, the process branches to step S13. On the other hand, if it is determined that the driver D has no intention to take over driving, the process proceeds to step S14. The processes in steps S11 and S12 correspond to the intention determination unit of the present invention.

[0048] When the process proceeds to step S13, the driving mode is transitioned from the automatic driving mode to the manual driving mode, and the routine is terminated. As a result, the automatic driving is cancelled, and the driver D drives the vehicle M by operating the steering wheel and the accelerator. If the failure of the automatic driving sensor is a temporary failure and is restored during the manual driving mode, for example, the fact may be displayed on a multi-information display arranged on the instrument panel. In this case, the driver can execute the automatic driving mode again by turning on the automatic driving switch. The process in step S13 corresponds to the manual driving transition section of the present invention.

[0049] In addition, when the process proceeds to step S14, the count value C of the counter timer is incremented (C←C+1) to measure the waiting time, and the process proceeds to step S15. The initial value of this count value C is 0. In this embodiment, the handover waiting time Co is set to a value corresponding to about 8 to 12 [sec].

[0050] In step S15, the count value C is compared with the handover waiting time Co. This handover waiting time Co is the maximum allowable waiting time when the driving mode is transitioned from the automatic driving mode to the manual driving mode, and is determined in advance for each vehicle model through experiments or the like.

[0051] As described above, while driving in the autonomous driving mode, the driver is allowed to perform a second task, so as shown in Fig. 6(b), the driver takes his / her hands off the steering wheel H and sits in the driver's seat in a relaxed posture. In such a relaxed posture, the driver's movements tend to become slow, and it is difficult for the driver D to respond immediately even if the driving assistance control unit 11 notifies the driver D that the driving mode will be switched to the manual driving mode. Therefore, a time allowance is required to switch the driving mode to the manual driving mode.

[0052] Therefore, during this handover waiting time Co, even if one of the autonomous driving sensors fails, autonomous driving will continue under restricted conditions (e.g., with restrictions imposed on the vehicle speed) based on signals from other normal sensors.

[0053] And when C < Co, proceed to step S16 while continuing the standby state. On the other hand, when C ≥ Co, it is determined that the driver D has no intention of taking over the driving, and jump to step S21. Incidentally, the processing in steps S14 and S15 corresponds to the standby time measuring unit of the present invention.

[0054] When proceeding to step S16, based on the output of the automatic driving sensor, it is checked whether the forward recognition sensor 21 included in this automatic driving sensor is malfunctioning. And when it is determined that the forward recognition sensor 21 is malfunctioning, branch to step S17. Also, when it is determined that the forward recognition sensor 21 is normal, proceed to step S18.

[0055] When branching to step S17, select the restricted accelerator opening table as the accelerator opening table to be referred to during the takeover standby time, and return to step S11. Incidentally, by the driving support control unit 11 referring to the restricted accelerator opening table selected in this step S17, the output of the drive source with respect to the accelerator opening (accelerator operation amount) θacc is restricted. Therefore, the processing in this step corresponds to the output limiting unit of the present invention.

[0056] FIGS. 4(a) and (b) show the characteristics of the accelerator opening table normally referred to and the restricted accelerator opening table referred to when the forward recognition sensor 21 malfunctions.

[0057] By the way, during driving in the automatic driving mode, the driver D is allowed a second task, and of course the foot that has left the accelerator pedal is in a state of being placed directly on the floor mat. In such a situation, if the driver D is notified from the notification device 34 to transition the driving mode to the manual driving mode, the driver may panic and accidentally step on the accelerator pedal.

[0058] In this case, even during the takeover standby time, basically if the driver D steps on the accelerator pedal, the automatic driving is temporarily interrupted and the host vehicle M accelerates.

[0059] The accelerator opening table that is referred to in normal operation is set with the output characteristics of the drive source that can be normally obtained for the accelerator opening θacc. In contrast, the limited accelerator opening table is set with characteristics that limit the output of the drive source for the accelerator opening θacc. The output control of the drive source corresponding to the accelerator opening θacc includes control using a target drive torque Tp as shown in Figure 4(a) and control using a target acceleration αp as shown in Figure 4(b).

[0060] In the control by the target drive torque Tp shown in Fig. 4(a), if the characteristic of the accelerator opening table referred to in the normal state is that the accelerator opening θacc and the target drive torque Tp correspond 1:1 as shown by the dashed line, the characteristic of the limited accelerator opening table shown by the solid line is that the target drive torque Tp increases gradually with an increase in the accelerator opening θacc until it reaches the set drive torque T1, and after it reaches the set drive torque T1, the target drive torque Tp is kept constant regardless of the increase in the accelerator opening θacc. Therefore, with the limited accelerator opening table, the vehicle M will not suddenly accelerate even if the driver D accidentally depresses the accelerator pedal.

[0061] On the other hand, in the control based on the target acceleration αp shown in Fig. 4(b), the relationship between the accelerator opening θacc and the target acceleration αp is almost proportional. If the relationship between the accelerator opening and the target acceleration αp in the accelerator opening table referenced during normal times, shown by the dashed line in the figure, is set to 1:1, the limited accelerator opening table, shown by the solid line, has a characteristic in which the slope is set small. Therefore, with the limited accelerator opening table, even if the driver D accidentally depresses the accelerator pedal, the host vehicle M will not suddenly accelerate.

[0062] If the forward recognition sensor 21 is normal, even if the driver D depresses the accelerator pedal, the well-known ACC control and AEB control function, and the host vehicle M can avoid contact with a forward obstacle including the preceding vehicle F in a situation where the host vehicle M approaches the forward obstacle. Therefore, the accelerator opening degree table that is normally referred to is applied as it is even during the handover waiting time.

[0063] On the other hand, if the forward recognition sensor 21 is out of order, the driving assistance control unit 11 cannot accurately recognize obstacles in front of the vehicle, including the preceding vehicle. Therefore, the ACC control and the AEB control cannot be operated, so the limited accelerator opening table is applied. To suppress sudden acceleration even if a driver D accidentally depresses an accelerator pedal.

[0064] Also, when the process proceeds from step S16 to step S18, it is checked whether or not an obstacle including the preceding vehicle F has been detected ahead based on the forward driving environment information acquired by the forward recognition sensor 21. Then, if no obstacle has been detected, the process branches to step S19, where constant speed ACC control is executed to drive the host vehicle M at a set vehicle speed set by the driver D, and the process returns to step S11. Also, if an obstacle has been detected, the process proceeds to step S20, where ACC control and AEB control are executed, and the process returns to step S11.

[0065] On the other hand, if it is determined that the driver D has no intention of taking over driving and the process jumps from step S15 to step S21, the MRM mode is executed and the routine ends. As a result, the driving assistance control unit 11 blinks the hazard lights and automatically moves the host vehicle M to a safe place such as a road shoulder while reducing the host vehicle speed.

[0066] Next, FIGS. 7 and 8 illustrate the transition of the driving mode set in the handover request processing subroutine. First, with reference to the time chart shown in FIG. 7(a), a control example when the forward recognition sensor 21 fails will be described. When the driving assistance control unit 11 detects a failure of the automatic driving sensor during driving in the automatic driving mode, it notifies the driver D of a handover request for driving and starts counting the count value C of the counter timer.

[0067] Also, if the forward recognition sensor 21 is included in the failure of this automatic driving sensor, the restricted accelerator opening table shown by the solid line in FIGS. 4(a) and (b) is selected, and the output of the drive source is restricted. Therefore, even if the driver D steps on the accelerator pedal excessively, sudden acceleration is suppressed. And when the driver D shows the intention to take over the driving (visually recognize the front and hold the steering wheel H) within the handover waiting time Co (C < Co), the driving mode is changed from the automatic driving mode to the manual driving mode.

[0068] Next, with reference to the time chart shown in FIG. 7(b), a control example when the automatic driving sensor fails but the forward recognition sensor 21 is normal will be described. When the driving assistance control unit 11 detects a failure of the automatic driving sensor during driving in the automatic driving mode, it notifies the driver D of a handover request for driving and starts counting the count value C of the counter timer. Since the forward recognition sensor 21 is normal, the normal accelerator opening table shown by the dashed-dotted line in FIGS. 4(a) and (b) is selected. When the forward recognition sensor 21 is normal, the forward obstacle can be detected by this forward recognition sensor 21, and the ACC control and the AEB control can be activated. Therefore, even if the driver D accidentally steps on the accelerator pedal, interference with the forward obstacle can be avoided.

[0069] Next, with reference to the time chart shown in FIG. 8, a control example will be described in which the forward recognition sensor 21 fails and the driver does not indicate his / her intention to take over driving within the handover waiting time Co. As in FIG. 7(a) described above, when the driving assistance control unit 11 detects a failure of the automatic driving sensor during driving in the automatic driving mode, it notifies the driver D of a request to take over driving and starts measuring the count value C of the counter timer. In addition, if the forward recognition sensor 21 is included in the failure of the automatic driving sensor, the output of the drive source is limited. Then, if the driver D does not indicate his / her intention to take over driving even after the handover waiting time Co has elapsed (C≧Co), the driving mode is transitioned from the automatic driving mode to the MRM mode.

[0070] In this embodiment, when the driving mode is transitioned from the automatic driving mode to the manual driving mode due to a failure of the forward recognition sensor 21, the driving assistance control unit 11 refers to the limited accelerator opening table and limits the output of the driving source for the accelerator opening θacc within the driving mode takeover time Co. Therefore, even if the driver D accidentally depresses the accelerator pedal within this takeover time Co, sudden acceleration is suppressed, the driver D is not panicked, and good controllability can be obtained.

[0071] It should be noted that the present invention is not limited to the above-described embodiment. For example, the forward recognition sensor 21 may be configured by a combination of a monocular camera and a laser sensor. [Explanation of symbols]

[0072] 1...Driving assistance device, 11...Driver assistance control unit, 21...Forward recognition sensor, 21A...imaging area, 21a…Main camera, 21b…Sub camera, 23...Map locator unit, 23a…GNSS sensor, 23b…Road map database, 24...Autonomous driving sensor, 25...Vehicle speed sensor, 26...Accelerator opening sensor, 27, 28…Left and right front side sensors, 27A, 28A...scanning area, 29, 30…Right and left rear side sensors, 29A, 30A...scanning area, 31...driving intention detection sensor, 31A…Driver monitor system, 31B…Handle touch sensor, 31C…Steering torque sensor, 32...Steering shaft, 33...Drive control actuator, 34...Alarm device, D…Driver, F… Leading vehicle, H…Handle, M…own vehicle, P: adjacent vehicle, T1: Set driving torque, C: Count value, Co…Handover waiting time, Tp: target drive torque, αp…Target acceleration, θacc…Accelerator opening

Claims

1. A driving environment information acquisition unit that acquires driving environment information ahead of the host vehicle; a driving state information acquisition unit for acquiring driving state information of the host vehicle; A driving control unit that executes automatic driving control of the host vehicle based on the driving environment information acquired by the driving environment information acquisition unit and the driving state information detected by the driving state information acquisition unit, a failure detection unit that detects a failure of the driving environment information acquisition unit and the driving state information acquisition unit; a handover request processing unit that executes a handover request process to switch to manual driving when the failure detection unit detects a failure in at least one of the driving environment information acquisition unit and the driving state information acquisition unit while the driving control unit is driving the host vehicle under the automatic driving control; Further comprising: The takeover request processing unit, an output limiting section that measures a standby time from when the failure detection section detects a failure until transition to the manual driving, and when it detects an operation of an accelerator pedal by a driver during the standby time, temporarily suspends the automatic driving control and limits the output of the drive source in response to an amount of accelerator operation by the driver to be smaller than the output during the manual driving. A vehicle driving assistance device comprising:

2. The takeover request processing unit, An intention determination unit that determines the driver's intention to take over; a manual driving transition unit that transitions to the manual driving when the intention determination unit determines that the driver has an intention to take over; 2. The vehicle driving support device according to claim 1, further comprising:

3. A direction determination unit that determines a direction of the driver's face; A grip detection unit that detects a driver's grip on a steering wheel; Further comprising: The intention determination unit determines that the driver has an intention to take over when the orientation determination unit determines that the driver is facing forward and the grip detection unit detects that the driver is gripping the steering wheel.

3. The vehicle driving support device according to claim 2.

4. The output limiting unit: When the failure detection unit detects a failure of the driving environment information acquisition unit, the failure detection unit limits the output of the driving source in response to the accelerator operation amount by the driver during the waiting time, and when the failure detection unit detects a failure of the driving state information acquisition unit but does not detect a failure of the driving environment information acquisition unit, the failure detection unit does not limit the output of the driving source in response to the accelerator operation amount by the driver during the waiting time.

2. The vehicle driving support device according to claim 1.

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