Vehicle travel control device and method

Abstract

To provide a vehicle travel control device and a method improved so as to reduce possibility of deviation when a steering operation is not the one positively making a vehicle deviate from a lane even when the steering operation is performed by a driver in a situation where the vehicle has possibility to deviate to the outside of the lane.SOLUTION: A vehicle travel control device includes: a sensor detecting a steering operation; a target information acquisition device acquiring information on a target around a vehicle; an automatic braking device automatically braking the vehicle; and a drive support ECU controlling the automatic braking device. The drive support ECU actuates the automatic braking device to perform automatic brake automatically braking the vehicle when determining that the vehicle has possibility of deviation to the outside of the lane on the basis of information on a target acquired by the target information acquisition device (S20) and also determining that the steering operation in a direction where the vehicle deviates to the outside of the lane is performed on the basis of the steering operation detected by the sensor (S30).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a vehicle driving control device and method for vehicles such as automobiles, and more particularly to a driving control device and method for suppressing a vehicle from deviating off the road.

Background Art

[0002] As one of the vehicle driving control devices for vehicles such as automobiles, when there is a risk that the vehicle may deviate from the lane, the vehicle lane departure is suppressed by automatic braking or warning of the vehicle. However, when a steering operation is performed by the driver, there is known a lane departure suppression device that does not perform automatic braking or warning.

[0003] For example, Patent Document 1 below describes a technique for changing the condition for canceling a warning according to the driver's level of wakefulness when a steering operation is performed by the driver in a situation where the vehicle may deviate from the lane.

[0004] According to this type of lane departure suppression device, even if there is a risk that the vehicle may deviate from the lane, when the driver performs a steering operation and tries to actively deviate from the lane, it is possible to prevent unnecessary automatic braking or warning from being performed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] 〔Problems to be Solved by the Invention〕 Even when a steering operation is performed by the driver in a situation where there is a risk that the vehicle may deviate from the lane, the driver does not necessarily intend to actively deviate from the lane. When the driver does not intend to actively deviate the vehicle from the lane, it is preferable that automatic braking or warning is not canceled even if a steering operation is performed by the driver.

[0007] In particular, when there is a risk that the vehicle may deviate off the road, it is possible to determine whether the driver is attempting to actively deviate from the lane by determining whether the direction of the steering operation by the driver is a steering operation in the direction in which the vehicle may deviate off the road.

[0008] The present invention provides an improved driving control device and method capable of reducing the risk of deviation when, even when a steering operation is performed by a driver in a situation where there is a risk that the vehicle may deviate off the road, the steering operation is not a steering operation that actively causes the vehicle to deviate from the lane.

[0009] 〔Means for Solving the Problem and Effects of the Invention〕 According to the present invention, there is provided a vehicle driving control device (100) including a steering operation detection device (driving operation sensor 60) that detects a driver's steering operation, a target information acquisition device (15) that acquires information on a target around the vehicle (102), an automatic braking device (36) that automatically brakes the vehicle, and a control unit (driving support ECU 10) that controls the automatic braking device.

[0010] When the control unit (driving support ECU 10) determines that there is a risk of deviation (S20) that the vehicle may deviate off the road based on the information on the target acquired by the target information acquisition device and determines that a steering operation in the direction in which the vehicle may deviate off the road has been performed based on the steering operation detected by the steering operation detection device (S30), it is configured to perform automatic braking (S140, S170) by activating the automatic braking device to automatically brake the vehicle.

[0011] Further, according to the present invention, there is provided a vehicle driving control method including a step (S20) of acquiring information on a target around the vehicle (102) and determining a risk of deviation that the vehicle may deviate off the road based on the acquired information on the target, and a step (S140, S170) of performing automatic braking by activating the automatic braking device to automatically brake the vehicle when it is determined that there is a risk of deviation (S110).

[0012] The running control method further detects a driver's steering operation and, even if it is determined that there is a risk of deviation (S20), when it is determined that a steering operation in a direction other than the direction in which the vehicle deviates off the road has been performed (S30), automatic braking is not performed (S60), and when it is determined that there is a risk of deviation (S20) and it is determined that a steering operation in the direction in which the vehicle deviates off the road has been performed (S30), automatic braking is performed (S70, S140, S170).

[0013] According to the above running control device and method, information on targets around the vehicle is acquired, and it is determined whether there is a risk that the vehicle will deviate off the road based on the acquired target information. Further, when it is determined that there is a risk that the vehicle will deviate off the road and it is determined that a steering operation in the direction in which the vehicle deviates off the road has been performed, automatic braking is performed.

[0014] Even if a driver performs a steering operation in a situation where there is a risk that the vehicle will deviate off the road, if the direction of the steering operation is the direction in which the vehicle deviates off the road, the steering operation may be regarded as not being a steering operation actively performed by the driver to control the running direction of the vehicle. According to the above running control device and method, in this case, automatic braking is performed. Therefore, compared with a conventional running control device where automatic braking is not performed regardless of the steering direction when a steering operation is performed, the risk that the vehicle will deviate off the road can be reduced.

[0015] Note that the reduction of the risk that the vehicle will deviate off the road is achieved by automatically braking the vehicle, and no automatic steering operation, that is, automatic steering of the steering wheel, is performed against the driver's steering operation. Therefore, even if a situation occurs where the determination of the direction in which the vehicle deviates off the road and / or the direction of the steering operation is not properly performed, the automatic steering operation will not be inappropriately performed due to this, and the running direction of the vehicle will not be inappropriately controlled.

[0016] 〔Aspects of the Invention〕 In one aspect of the present invention, the control unit (driving support ECU 10) is configured to perform automatic braking (S70, S140, S170) when it is determined that the risk of deviation is equal to or greater than a first deviation reference value (S120) and it is determined that the related value of the steering operation is equal to or greater than a first steering reference value (S10).

[0017] According to the above aspect, automatic braking is performed when it is determined that the risk of deviation is equal to or greater than the first deviation reference value and it is determined that the related value of the steering operation is equal to or greater than the first steering reference value. Therefore, even when it is determined that the risk of deviation is equal to or greater than the first deviation reference value, if it is determined that the related value of the steering operation is less than the first steering reference value, automatic braking is not performed, so that it is possible to avoid unnecessary automatic braking.

[0018] The related value of the steering operation is an index value for determining whether the driver has performed a steering operation, and may be a steering torque, a steering angle, or the like.

[0019] In another aspect of the present invention, the driving control device (100) further includes a driving state information acquisition device (monitor camera 16) that acquires information on the driving state of the driver. The control unit (driving support ECU 10) determines whether the driving state of the driver is a casual driving state based on the driving state information acquired by the driving state information acquisition device (S2). When it is determined that the driving state of the driver is not a casual driving state, when it is determined that the risk of deviation is equal to or greater than a first deviation reference value (S120) and it is determined that the related value of the steering operation is equal to or greater than a first steering reference value (S4, S10), automatic braking is performed (S70, S140, S170). When it is determined that the driving state of the driver is a casual driving state, when it is determined that the risk of deviation is equal to or greater than a first deviation reference value (S120) and it is determined that the related value of the steering operation is equal to or greater than a second steering reference value smaller than the first steering reference value (S6, S10), it is configured to perform automatic braking.

[0020] Generally, when the driver's driving state is a careless driving state, the relevant value of the steering operation is smaller than when the driver is awake. Therefore, the reference value for determining whether the steering operation is performed by the driver based on the relevant value of the steering operation is preferably smaller when the driver's driving state is a careless driving state than when the driver is awake.

[0021] According to the above aspect, when it is determined that the driver's driving state is not a careless driving state, automatic braking is performed when it is determined that the risk of deviation is equal to or greater than the first deviation reference value and it is determined that the relevant value of the steering operation is equal to or greater than the first steering reference value. On the other hand, when it is determined that the driver's driving state is a careless driving state, automatic braking is performed when it is determined that the risk of deviation is equal to or greater than the first deviation reference value and it is determined that the relevant value of the steering operation is equal to or greater than the second steering reference value which is smaller than the first steering reference value.

[0022] Therefore, compared with the case where the steering reference value is constant regardless of whether the driver's driving state is a careless driving state, it is possible to appropriately determine whether the steering operation is performed by the driver based on the relevant value of the steering operation even in a situation where the driver's driving state is a careless driving state.

[0023] Furthermore, in another aspect of the present invention, when performing automatic braking, the control unit (driving support ECU 10) is configured to perform automatic braking at the first deceleration (S140) when it is determined that the risk of deviation is less than the second deviation reference value which is greater than the first deviation reference value (S120, S130), and to perform automatic braking at the second deceleration which is higher than the first deceleration (S170) when it is determined that the risk of deviation is equal to or greater than the second deviation reference value (S120, S130).

[0024] Generally, in order to reduce the risk of the vehicle deviating off the road by automatic braking, it is preferable that the higher the risk of the vehicle deviating off the road, the higher the deceleration of the vehicle by automatic braking.

[0025] According to the above aspect, when it is determined that the risk of deviation is less than a second deviation reference value that is greater than the first deviation reference value, automatic braking is performed at the first deceleration, and when it is determined that the risk of deviation is equal to or greater than the second deviation reference value, automatic braking is performed at a second deceleration that is higher than the first deceleration. Therefore, compared with the case where the deceleration of the vehicle by automatic braking is constant regardless of the level of the risk of deviation, the deceleration of the vehicle by automatic braking can be appropriately controlled.

[0026] In the present application, "off-road" means the side of the boundary between the driving area where the vehicle can travel and the non-driving area where the vehicle cannot travel, on the non-driving area side. "Deviating off-road" means that the preset reference position of the vehicle moves from the driving area to the non-driving area. The lane on which the vehicle travels, the roadside strip where the vehicle can travel, the escape lane, etc. may be regarded as the driving area. On the other hand, the area outside the road, the roadside strip where the vehicle cannot travel, etc. may be regarded as the non-driving area.

[0027] In the above description, for the purpose of assisting the understanding of the present invention, the names and / or symbols used in the embodiments are added in parentheses to the configurations of the invention corresponding to the embodiments described later. However, each component of the present invention is not limited to the components of the embodiments corresponding to the names and / or symbols added in parentheses. Other objects, other features, and accompanying advantages of the present invention will be easily understood from the description of the embodiments of the present invention described with reference to the following drawings.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0029] With reference to the attached drawings below, a vehicle driving control device and a driving control method according to an embodiment of the present invention will be described in detail.

[0030] As shown in FIG. 1, a driving control device 100 according to an embodiment of the present invention is applied to a vehicle 102 and includes a driving support ECU 10. The vehicle 102 is a vehicle capable of autonomous driving and includes a drive ECU 20, a brake ECU 30, an electric power steering ECU 40, and a meter ECU 50. An ECU means an electronic control unit (Electronic Control Unit) mainly including a microcomputer. In the following description, electric power steering is referred to as EPS.

[0031] The microcomputer of each ECU includes a CPU, a ROM, a RAM, a readable and writable non-volatile memory (N / M), and an interface (I / F), etc. The CPU realizes various functions by executing instructions (programs, routines) stored in the ROM. Further, these ECUs are connected to each other via a CAN (Controller Area Network) 104 so that data can be exchanged (communicated). Therefore, detection values of sensors (including switches) connected to a specific ECU are also transmitted to other ECUs.

[0032] The driving support ECU 10 is a central control device that performs driving control for driving support such as lane departure suppression control and inter-vehicle distance control. In the embodiment, as will be described in detail later, the driving support ECU 10 cooperates with other ECUs to execute lane departure suppression control. The driving control of the embodiment is executed as a part of the lane departure suppression control.

[0033] A camera sensor 12, a radar sensor 14, a monitor camera 16, and a switch 18 are connected to the driving support ECU 10. The camera sensor 12 and the radar sensor 14 each include a plurality of camera devices and a plurality of radar devices. The camera sensor 12 and the radar sensor 14 function as a target information acquisition device 15 that acquires target information around the vehicle 102.

[0034] Although not shown in the figure, each camera device of the camera sensor 12 includes a camera unit that photographs the surroundings of the vehicle 102, and a recognition unit that analyzes the image data obtained by the camera unit to recognize targets such as white lines on the road and other vehicles. The recognition unit supplies information about the recognized targets to the driving support ECU 10 at predetermined time intervals.

[0035] Each radar device of the radar sensor 14 includes a radar transceiver and a signal processing unit (not shown). The radar transceiver emits radio waves in the millimeter wave band (hereinafter referred to as "millimeter waves"), and receives the millimeter waves (i.e., reflected waves) reflected by solid objects (e.g., other vehicles, bicycles, etc.) existing within the radiation range. The signal processing unit supplies information representing the distance between the host vehicle and the solid object, the relative speed between the host vehicle and the solid object, the relative position (direction) of the solid object with respect to the host vehicle, etc. to the driving support ECU 10 at predetermined time intervals based on the phase difference between the transmitted millimeter waves and the received reflected waves, the attenuation level of the reflected waves, and the time from transmitting the millimeter waves to receiving the reflected waves. Note that LiDAR (Light Detection And Ranging) may be used instead of or in addition to the radar sensor 14.

[0036] The monitor camera 16 is provided on the dashboard or the steering column, and includes a camera unit that captures the driver's face, and an image processing unit that processes the image data of the driver's face obtained by the camera unit. The image processing unit supplies information on the image data of the driver's face to the driving support ECU 10 at predetermined time intervals. Therefore, the monitor camera 16 functions as a driver monitor camera.

[0037] Based on the information of the image data of the driver's face, the CPU of the driving support ECU 10 determines the non-arousal level of the driver from, for example, the driver's per-minute eye closure rate, the state of eye opening, the frequency of blinking, or eye movement. The non-arousal level indicates the degree to which the driver is inattentive due to lack of sleep or the like and is not suitable for driving. The method for determining the non-arousal level is not particularly limited, and any method known in the art may be adopted. Further, when determining the non-arousal level, at least any one of the grip pressure of the driver's steering wheel, the pressing force on the armrest, the heart rate, the electromyogram information, and the brain wave pattern may be considered.

[0038] The switch 18 is provided at a position operable by the driver, like a steering wheel not shown in FIG. 1, and is configured to be operated by the driver. As will be described in detail later, the driving support ECU 10 executes lane departure suppression control when the switch 18 is on.

[0039] A drive device 22 that accelerates the vehicle 102 by applying a driving force to the drive wheels 24 is connected to the drive ECU 20. Normally, the drive ECU 20 controls the drive device 22 so that the driving force generated by the drive device 22 changes according to the driving operation by the driver, and when receiving a command signal from the driving support ECU 10, controls the drive device 22 based on the command signal.

[0040] The braking ECU 30 is connected to a braking device 32 that decelerates the vehicle 102 by applying a braking force to the wheels 34. During normal operation, the braking ECU 30 controls the braking device so that the braking force generated by the braking device 32 changes according to the braking operation by the driver. When receiving a command signal from the driving assistance ECU 10, it performs automatic braking by controlling the braking device 32 based on the command signal.

[0041] Therefore, the braking ECU 30 and the braking device 32 cooperate with each other to function as an automatic braking device 36. When a braking force is applied to the wheels due to lane departure suppression control or the like, a brake lamp (not shown in FIG. 1) is lit.

[0042] An EPS·ECU 40 is connected to an EPS device 42. Based on the steering torque Ts and the vehicle speed V detected by a driving operation sensor 60 and a vehicle state sensor 70, which will be described later, the EPS·ECU 40 controls the EPS device 42 in a manner known in the art to control the steering assist torque and reduce the driver's steering burden. Also, the EPS·ECU 40 can steer the steering wheel 44 as needed by controlling the EPS device 42. Therefore, the EPS·ECU 40 and the EPS device 42 function as an automatic steering device that automatically steers the steering wheel as needed.

[0043] A meter ECU 50 is connected to a touch panel type display 52 that displays the status of control by the driving assistance ECU 10 and an alarm device 54 that issues an alarm. The display 52 may be, for example, a multi-information display on which meters and various information are displayed, or may be a display of a navigation device. The display 52 may be configured to display the status of lane departure suppression control when receiving a signal from the driving assistance ECU 10.

[0044] The warning device 54 is activated when it is determined that the vehicle 102 may deviate off the road, and issues a warning as one of the lane departure suppression controls, that is, issues a warning indicating that the vehicle 102 may deviate off the road. The warning device 54 may be any of a warning device that emits a visual warning such as a warning lamp, a warning device that emits an auditory warning such as a warning buzzer, and a warning device that emits a tactile warning such as vibration of the seat, or any combination thereof.

[0045] The driving operation sensor 60 and the vehicle state sensor 70 are also connected to the CAN 104. Information detected by the driving operation sensor 60 and the vehicle state sensor 70 (referred to as sensor information) is transmitted to the CAN 104. The sensor information transmitted to the CAN 104 can be appropriately used in each ECU. Note that the sensor information is information of a sensor connected to a specific ECU, and may be transmitted from the specific ECU to the CAN 104.

[0046] The driving operation sensor 60 includes a drive operation amount sensor that detects the operation amount of the accelerator pedal, a braking operation amount sensor that detects the master cylinder pressure or the stepping force on the brake pedal, and a brake switch that detects the presence or absence of the operation of the brake pedal. Further, the driving operation sensor 60 includes a steering angle sensor that detects the steering angle θ, a steering torque sensor that detects the steering torque Ts, a turn signal switch that indicates the presence or absence and the direction of the operation of the turn signal lever, and the like.

[0047] The vehicle state sensor 70 includes a vehicle speed sensor that detects the vehicle speed V of the vehicle 102, a longitudinal acceleration sensor that detects the longitudinal acceleration of the vehicle, a lateral acceleration sensor that detects the lateral acceleration of the vehicle, and a yaw rate sensor that detects the yaw rate of the vehicle, and the like.

[0048] [First Embodiment] In the first embodiment, the ROM of the driving support ECU 10 stores a lane departure and steering determination control program corresponding to the flowchart shown in FIG. 2. Also, in the first embodiment, the ROM of the driving support ECU 10 stores an automatic braking control program for lane departure suppression corresponding to the flowchart shown in FIG. 3. The driving control method according to the first embodiment is executed by performing lane departure and steering determination control and automatic braking control for lane departure suppression according to the flowcharts shown in FIGS. 2 and 3, respectively.

[0049] <Lane departure and steering determination control (FIG. 2)> Next, the lane departure and steering determination control in the first embodiment will be described with reference to the flowchart shown in FIG. 2. The lane departure and steering determination control according to the flowchart shown in FIG. 2 is repeatedly executed by the CPU of the driving support ECU 10 at predetermined time intervals in a situation where the switch 18 is on. At the start of the lane departure and steering determination control, the flag F is reset to 0.

[0050] First, in step S10, the CPU determines whether the absolute value of the steering torque Ts is equal to or greater than the reference value Tsc, that is, whether a steering operation is being performed by the driver. When a negative determination is made, this control proceeds to step S60, and when an affirmative determination is made, this control proceeds to step S20. The reference value Tsc may be a positive constant, or may be a positive value variably set according to the vehicle speed V so as to become smaller as the vehicle speed V is higher.

[0051] In step S20, the CPU determines whether there is a risk of lane departure, that is, whether the vehicle 102 is about to deviate off the road, based on the target information around the vehicle 102 acquired by, for example, the target information acquisition device 15, in a manner known in the art. When a negative determination is made, this control proceeds to step S60, and when an affirmative determination is made, this control proceeds to step S30.

[0052] In step S30, the CPU determines, based on the steering angle θ detected by, for example, a steering angle sensor and its change, whether the direction of the driver's steering operation is the direction in which the vehicle 102 determined in step S20 deviates off the road. When a negative determination is made, this control proceeds to step S60, and when an affirmative determination is made, this control proceeds to step S40.

[0053] In step S40, the CPU determines, based on the presence or absence of the operation of the turn signal lever indicated by the turn signal switch and the direction of the operation, whether the turn signal lever has been operated by the driver in the direction corresponding to the steering direction determined in step S30. When an affirmative determination is made, this control proceeds to step S60, and when a negative determination is made, this control proceeds to step S50.

[0054] In step S50, the CPU determines, based on the target information around the vehicle 102 acquired by, for example, the target information acquisition device 15, whether the area ahead in the direction in which the vehicle 102 determined in step S20 deviates off the road is a non-driving area, that is, an area where the vehicle cannot travel. When a negative determination is made, in step S60, the flag F is reset to 0, and when an affirmative determination is made, the flag F is set to 1. Note that the fact that the flag F is 1 indicates that there is a risk that the vehicle 102 may deviate off the road and that control for suppressing the deviation is necessary.

[0055] <Automatic Braking Control for Lane Departure Suppression (Figure 3)> Next, with reference to the flowchart shown in FIG. 3, the braking force control for preventing lane departure in the first embodiment will be described. The braking force control according to the flowchart shown in FIG. 3 is repeatedly executed by the CPU of the driving support ECU 10 at predetermined time intervals when the switch 18 is on.

[0056] First, in step S110, the CPU determines whether the flag F is 1, that is, whether there is a risk that the vehicle 102 will deviate off the road and whether control to suppress the deviation is necessary. When a negative determination is made, this control ends once. When an affirmative determination is made, this control proceeds to step S120.

[0057] In step S120, the CPU calculates the time Te until the vehicle deviates off the road in a manner known in the art based on, for example, the target information around the vehicle 102 acquired by the target information acquisition device 15. Further, the CPU determines whether the time Te is less than or equal to a first reference time Tec1 (a positive constant), that is, whether the risk that the vehicle will deviate off the road is equal to or greater than a first reference value. When a negative determination is made, this control ends once. When an affirmative determination is made, this control proceeds to step S130. Note that the time Te may be calculated, for example, as the time until a preset reference position of the vehicle reaches the boundary between the road and the off-road area based on the lateral speed of the vehicle 102.

[0058] In step S130, the CPU determines whether the time Te is less than or equal to a second reference time Tec2 (a positive constant smaller than Tec1), that is, whether the risk that the vehicle will deviate off the road is equal to or greater than a second reference value. When an affirmative determination is made, this control proceeds to step S150. When a negative determination is made, that is, when it is determined that the risk that the vehicle will deviate off the road is equal to or greater than the first reference value and less than the second reference value, this control proceeds to step S140.

[0059] In step S140, the CPU outputs a command signal to the brake ECU 30 to execute mild braking control by automatic braking by the automatic braking device 36 so that the deceleration Gb of the vehicle 102 becomes a first deceleration Gb1 (a positive constant with the deceleration direction being positive). Further, the CPU outputs a command signal to the meter ECU 50 to issue an intermittent sound alarm by the buzzer device.

[0060] In step S150, the CPU determines whether a braking operation has been performed by the driver based on the detection result of the braking operation amount sensor or the status of the brake switch. When an affirmative determination is made, this control ends once. When a negative determination is made, this control proceeds to step S160.

[0061] In step S160, the CPU determines whether a steering operation in a direction opposite to the direction in which the vehicle 102 deviates off the road is being performed by the driver based on, for example, the steering angle θ detected by the steering angle sensor and its change. When an affirmative determination is made, this control ends once. When a negative determination is made, this control proceeds to step S170. Note that when no steering operation is being performed by the driver, a negative determination is made.

[0062] In step S170, the CPU outputs a command signal to the braking ECU 30 to execute forced braking control by automatic braking by the automatic braking device 36 so that the deceleration Gb of the vehicle 102 becomes the second deceleration Gb2 (a positive constant much larger than Gb1). Also, the CPU outputs a command signal to the meter ECU 50 to issue a continuous sound alarm by the buzzer device.

[0063] 〔Second Embodiment〕 In the second embodiment, the ROM of the driving support ECU 10 stores a lane departure and steering determination control program corresponding to the flowchart in which the main part is shown in FIG. 4. Note that the automatic braking control program for lane departure suppression in the second embodiment is the same as the automatic braking control program for lane departure suppression in the first embodiment. The driving control method according to the second embodiment is executed by performing lane departure and steering determination control and automatic braking control for lane departure suppression according to the flowcharts shown in FIGS. 4 and 3, respectively.

[0064] <Lane Departure and Steering Determination Control (FIG. 4)> As shown in FIG. 4, steps S2 and S4 or steps S2 and S6 are executed prior to step S10, and steps S10 to S70 are executed in the same manner as in the first embodiment.

[0065] In step S2, the CPU determines whether the driver is in a distracted driving state. When a negative determination is made, in step S4, the reference value Tsc used for the determination in step S10 is set to the standard reference value Tscn. On the other hand, when an affirmative determination is made, in step S6, the reference value Tsc is set to the reference value Tscs during distracted driving, which is smaller than the standard reference value Tscn. When step S4 or S6 is completed, this control proceeds to step S10. Note that the reference values Tscn and Tscs may be positive constants, or may be positive values variably set according to the vehicle speed V such that they become smaller as the vehicle speed V increases.

[0066] <Determination of distracted driving state> The determination of whether the driver is in a distracted driving state may be made in any known manner in the art based on the information of the image data of the driver's face captured by the monitor camera 16. For example, this determination may be made according to a routine corresponding to the flowchart shown in FIG. 5.

[0067] In step S210, the CPU determines whether both eyes of the driver are closed. When an affirmative determination is made, this control proceeds to step S250, and when a negative determination is made, this control proceeds to step S220.

[0068] In step S220, the CPU determines whether the driver is looking away. When an affirmative determination is made, this control proceeds to step S250, and when a negative determination is made, this control proceeds to step S230. Note that the driver may be determined to be looking away when the time and frequency at which the direction of the driver's line of sight is not in front of the vehicle are each equal to or greater than the corresponding reference values.

[0069] In step S230, the CPU determines whether the driver is sleepy. When a negative determination is made, in step S240, it is determined that the driver is not in a distracted driving state. When an affirmative determination is made, in step S250, it is determined that the driver is in a distracted driving state. Note that when the direction of the driver's line of sight is below the forward direction, and when the frequencies of the driver's blinking and yawning are each equal to or greater than the corresponding reference values, it may be determined that the driver is sleepy.

[0070] <Effects of the First and Second Embodiments> As described above, even when a steering operation is performed by the driver in a situation where there is a risk that the vehicle may deviate off the road, if the direction of the steering operation is a direction that causes the vehicle to deviate off the road, that steering operation may be regarded as not being a steering operation actively performed by the driver to control the traveling direction of the vehicle.

[0071] According to the first and second embodiments described above, when the direction of the steering operation is determined, and it is determined that there is a risk that the vehicle may deviate off the road (S10) and it is determined that a steering operation in the direction in which the vehicle may deviate off the road has been performed (S30), automatic braking is performed. Therefore, compared with the case where automatic braking is not performed regardless of the steering direction when a steering operation is performed as in a conventional driving control device, the risk that the vehicle may deviate off the road can be reduced.

[0072] For example, FIG. 6 shows a situation where there is a risk that the vehicle 102 may deviate from the road 104, which is an area where the vehicle can travel, to the non - drivable area 106. In particular, FIG. 6(A) shows a situation where the steering wheel 108 is being operated by the driver in a direction away from the non - drivable area 106, and FIG. 6(B) shows a situation where the steering wheel 108 is being operated by the driver in a direction toward the non - drivable area 106.

[0073] In the situation shown in FIG. 6(A), an affirmative determination is made in step S20, but a negative determination is made in step S30, and the flag F is reset to 0 in step S60. Therefore, since a negative determination is made in step S110, steps S140 and S170 are not executed, and automatic braking and warning are not issued. Accordingly, in a situation where the driver is trying to avoid the vehicle from deviating off the road by a steering operation, it is possible to avoid unnecessary automatic braking and warning from being issued.

[0074] On the other hand, in the situation shown in FIG. 6(B), affirmative determinations are made in steps S20 and S30, and the flag F is set to 1 in step S70. Therefore, since an affirmative determination is made in step S110, steps S140 and S170 are executed, and automatic braking and warning are issued. Accordingly, it is possible to alert the driver and decelerate the vehicle, so that the risk of the vehicle 102 deviating into the non-drivable area 106 can be reduced.

[0075] Note that the reduction of the risk of the vehicle 102 deviating off the road is performed by issuing automatic braking and warning of the vehicle (S140, S170), and an automatic steering operation that counteracts the steering operation by the driver, that is, automatic steering of the steering wheel is not performed. Therefore, even if a situation occurs in which the determination of the direction in which the vehicle deviates off the road and / or the direction of the steering operation is not properly made, the automatic steering operation is not inappropriately performed due to this, so that the traveling direction of the vehicle is not inappropriately controlled.

[0076] Also, according to the first and second embodiments, when it is determined that the risk of deviation is equal to or greater than the first deviation reference value (S120) and it is determined that the related value of the steering operation is equal to or greater than the first steering reference value (S10), automatic braking is performed (S70, S140, S170). Therefore, even if it is determined that the risk of deviation is equal to or greater than the first deviation reference value, when it is determined that the related value of the steering operation is less than the first steering reference value, automatic braking is not performed, so that it is possible to avoid unnecessary automatic braking from being performed.

[0077] Also, according to the first and second embodiments, when it is determined that the risk of deviation is less than a second deviation reference value that is greater than the first deviation reference value (S120, S130), automatic braking is performed at the first deceleration Gb1 (S140), and when it is determined that the risk of deviation is equal to or greater than the second deviation reference value (S120, S130), automatic braking is performed at a second deceleration Gb2 that is higher than the first deceleration (S170). Therefore, compared to the case where the deceleration of the vehicle by automatic braking is constant regardless of the height of the risk of deviation, the deceleration of the vehicle by automatic braking can be appropriately controlled.

[0078] In particular, according to the second embodiment, when it is determined that the driving state of the driver is not a casual driving state (S2), and when it is determined that the risk of deviation is equal to or greater than the first deviation reference value (S120) and the related value of the steering operation is equal to or greater than the first steering reference value (S4, S10), automatic braking is performed (S70, S140, S170). On the other hand, when it is determined that the driving state of the driver is a casual driving state (S2), and when it is determined that the risk of deviation is equal to or greater than the first deviation reference value (S120) and the related value of the steering operation is equal to or greater than a second steering reference value that is smaller than the first steering reference value (S6, S10), automatic braking is performed.

[0079] Therefore, compared to the case where the steering reference value is constant regardless of whether the driving state of the driver is a casual driving state, it is possible to appropriately determine whether the driver has performed a steering operation based on the related value of the steering operation even in a situation where the driving state of the driver is a casual driving state.

[0080] Although the present invention has been described in detail with respect to specific embodiments above, it is obvious to those skilled in the art that the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention.

[0081] For example, in the above-described first and second embodiments, in step S130, when it is determined that the time Te is equal to or less than the second reference time Tec2, in step S140, a deceleration control is executed so that the deceleration Gb of the vehicle 102 becomes the first deceleration Gb1. However, steps S130 and S140 may be omitted.

[0082] Also, in the above-described first and second embodiments, in step S140, an intermittent sound alarm is issued, and in step S170, a continuous sound alarm is issued. However, the issuance of the alarm may be omitted.

[0083] Furthermore, in the above-described first and second embodiments, in steps S140 and S170, automatic steering for reducing the risk of the vehicle deviating off the road is not performed. However, at least in step S170, in addition to the automatic braking, automatic steering for reducing the risk of the vehicle deviating off the road may be performed. When automatic steering is performed in steps S140 and S170, the control amount of the automatic steering in step S170 may be set to be larger than the control amount of the automatic steering in step S140.

Description of Reference Numerals

[0084] 10... Driving support ECU, 12... Camera sensor, 14... Radar sensor, 15... Target information acquisition device, 16... Monitor camera, 22... Driving device, 32... Braking device, 36... Automatic braking device, 100... Travel control device, 102... Vehicle

Claims

1. In a vehicle driving control device including a steering operation detection device that detects a driver's steering operation, an object information acquisition device that acquires information on an object around the vehicle, an automatic braking device that automatically brakes the vehicle, and a control unit that controls the automatic braking device, when the control unit determines that there is a risk of the vehicle deviating off the road based on the information on the object acquired by the object information acquisition device and determines that a steering operation in the direction in which the vehicle deviates off the road has been performed based on the steering operation detected by the steering operation detection device, the control unit is configured to operate the automatic braking device to perform automatic braking to automatically brake the vehicle. A vehicle driving control device.

2. In the vehicle driving control device according to Claim 1, when the control unit determines that the risk of deviation is equal to or greater than a first deviation reference value and determines that a related value of the steering operation is equal to or greater than a first steering reference value, the control unit is configured to perform the automatic braking. A vehicle driving control device.

3. In the vehicle driving control device according to Claim 2, the driving control device further includes a driving state information acquisition device that acquires information on the driver's driving state, based on the driving state information acquired by the driving state information acquisition device, the control unit determines whether the driver's driving state is a casual driving state. When it is determined that the driver's driving state is not a casual driving state, when it is determined that the risk of deviation is equal to or greater than the first deviation reference value and the related value of the steering operation is equal to or greater than the first steering reference value, the automatic braking is performed. When it is determined that the driver's driving state is a casual driving state, when it is determined that the risk of deviation is equal to or greater than the first deviation reference value and the related value of the steering operation is equal to or greater than a second steering reference value smaller than the first steering reference value, the control unit is configured to perform the automatic braking. A vehicle driving control device.

4. In the vehicle travel control device according to claim 2 or 3, when performing the automatic braking, the control unit performs the automatic braking at a first deceleration when it is determined that the risk of deviation is less than a second deviation reference value that is greater than the first deviation reference value, and when it is determined that the risk of deviation is equal to or greater than the second deviation reference value, the vehicle travel control device is configured to perform the automatic braking at a second deceleration that is higher than the first deceleration.

5. A step of obtaining information on an object around the vehicle and determining a risk of deviation that the vehicle may deviate off the road based on the obtained object information; and a step of performing automatic braking to automatically brake the vehicle by operating the automatic braking device when it is determined that there is a risk of deviation. In a vehicle travel control method including: Furthermore, detecting a steering operation of the driver, and not performing the automatic braking when it is determined that there is a risk of deviation and it is determined that a steering operation in a direction other than the direction in which the vehicle may deviate off the road is performed, and performing the automatic braking when it is determined that there is a risk of deviation and it is determined that a steering operation in the direction in which the vehicle may deviate off the road is performed. A vehicle travel control method.

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