Vehicle driving 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's 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, in Patent Document 1 below, in a situation where there is a risk that the vehicle may deviate from the lane, when a steering operation is performed by the driver, a technique for changing the condition for canceling the warning according to the driver's level of wakefulness is described.

[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 attempts 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 the 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 of the vehicle deviating off the road, it is possible to determine whether the driver is actively trying to deviate from the lane by determining whether the direction of the driver's steering operation is in the direction that would cause the vehicle to deviate off the road.

[0008] The present invention provides an improved driving control device and method that can reduce the risk of a vehicle deviating from the road when the driver performs steering operations, provided that the steering operations are not intended to actively cause the vehicle to deviate from the lane.

[0009] [Means for solving the problem and the effects of the invention] According to the present invention, the vehicle includes a steering operation detection device (driving operation sensor 60) for detecting the driver's steering operation, a target information acquisition device (15) for acquiring information on targets around the vehicle (102), an automatic braking device (36) for automatically braking the vehicle, and a control unit (driving support ECU 10) for controlling the automatic braking device. Furthermore, the control unit (driving support ECU 10) is configured to perform automatic braking by activating the automatic braking device (S140, S170) when it determines, based on target information acquired by the target information acquisition device, that there is a risk of the vehicle deviating off the road (S20), and when it determines, based on steering operations detected by the steering operation detection device, that the vehicle has been steered in a direction that would cause it to deviate off the road (S30). A vehicle driving control device (100) is provided.

[0011] Furthermore, the present invention includes the steps of acquiring information on targets around the vehicle (102), determining whether there is a risk of the vehicle deviating off the road based on the acquired target information (S20), and, if it is determined that there is a risk of deviation (S110), performing automatic braking by activating an automatic braking device to automatically brake the vehicle (S140, S170). Furthermore, if the driver's steering operation is detected and it is determined that there is a risk of deviation (S20), but it is determined that the steering operation was performed in a direction other than the direction in which the vehicle would deviate off the road (S30), automatic braking will not be performed (S60). However, if it is determined that there is a risk of deviation (S20) and it is determined that the steering operation was performed in the direction in which the vehicle would deviate off the road (S30), automatic braking will be performed (S70, S140, S170). A method for controlling the movement of a vehicle is provided.

[0013] According to the above-described driving control device and method, information on targets around the vehicle is acquired, and based on the acquired target information, it is determined whether there is a risk of the vehicle deviating off the road. Furthermore, if it is determined that there is a risk of the vehicle deviating off the road and that steering operations have been performed in the direction of deviating off the road, automatic braking is performed.

[0014] Even if the driver steers the vehicle in a situation where there is a risk of the vehicle deviating off the road, if the direction of the steering operation is such that the vehicle deviates off the road, the steering operation may not be considered an operation performed by the driver to actively control the direction of travel of the vehicle. With the above-described driving control device and method, automatic braking is performed in this case, so the risk of the vehicle deviating off the road can be reduced compared to conventional driving control devices, where automatic braking is not performed regardless of the direction of steering operation.

[0015] Furthermore, the risk of the vehicle deviating off the road is reduced by automatically braking the vehicle, and automatic steering counteracting the driver's steering input, i.e., automatic steering of the steering wheels, is not performed. Therefore, even if a situation arises where the direction in which the vehicle deviates off the road and / or the direction of the steering input cannot be properly determined, this will not result in improper automatic steering, and thus the vehicle's direction of travel will not be improperly controlled.

[0019] Also, This invention According to the driving control device The driving control device (100) further includes a driving state information acquisition device (monitor camera 16) that acquires information on the driver's driving state, and the control unit (driving support ECU 10) is configured to determine whether the driver's driving state is a distracted driving state or not based on the driving state information acquired by the driving state information acquisition device (S2), and if it is determined that the driver's driving state is not a distracted driving state, it is determined that the risk of deviation is greater than or equal to a first deviation criterion value (S120) and the related value of the steering operation is greater than or equal to a first steering criterion value (S4, S10), and performs automatic braking (S70, S140, S170), and if it is determined that the driver's driving state is a distracted driving state, it is determined that the risk of deviation is greater than or equal to a first deviation criterion value (S120) and the related value of the steering operation is greater than or equal to a second steering criterion value which is smaller than the first steering criterion value (S6, S10), and performs automatic braking. Furthermore, according to the driving control method of the present invention, based on the driving state information acquired by the driving state information acquisition device (monitor camera 16) that acquires information on the driver's driving state, it is determined whether or not the driver's driving state is a state of distracted driving (S2). If it is determined that the driver's driving state is not a state of distracted driving, it is determined that the risk of deviation is greater than or equal to a first deviation criterion value (S120) and the related value of the steering operation is greater than or equal to a first steering criterion value (S4, S10), in which case automatic braking is performed (S70, S140, S170). If it is determined that the driver's driving state is a state of distracted driving, it is determined that the risk of deviation is greater than or equal to a first deviation criterion value (S120) and the related value of the steering operation is greater than or equal to a second steering criterion value which is smaller than the first steering criterion value (S6, S10), in which case automatic braking is performed. The steering-related values ​​are indicator values ​​used to determine whether or not steering operations were performed by the driver, and may include steering torque, steering angle, etc.

[0020] Generally, when a driver is in a distracted driving state, the value associated with steering operations is smaller compared to when the driver is alert. Therefore, when determining whether or not steering operations were performed by the driver based on the value associated with steering operations, it is preferable that the reference value be smaller when the driver is in a distracted driving state compared to when the driver is alert.

[0021] The above Driving control device and driving control method According to the system, when the driver's driving state is determined not to be a state of distracted driving, automatic braking is performed when the risk of deviation is determined to be equal to or greater than the first deviation threshold and the related value of the steering operation is determined to be equal to or greater than the first steering threshold. Conversely, when the driver's driving state is determined to be a state of distracted driving, automatic braking is performed when the risk of deviation is determined to be equal to or greater than the first deviation threshold and the related value of the steering operation is determined to be equal to or greater than the second steering threshold, which is smaller than the first steering threshold.

[0022] Therefore, compared to a situation where the steering reference value is constant regardless of whether the driver is driving distractedly or not, it is possible to properly determine whether or not the driver performed a steering operation based on the relevant values ​​of the steering operation, even when the driver is driving distractedly.

[0023] [Aspects of the Invention] Book invention One of the driving control devices In one embodiment, the control unit (driving support ECU 10) is configured to perform automatic braking at a first deceleration rate (S140) when it determines that the risk of deviation is less than a second deviation criterion value which is greater than a first deviation criterion value (S120, S130), and to perform automatic braking at a second deceleration rate which is higher than the first deceleration rate (S170) when it determines that the risk of deviation is greater than or equal to the second deviation criterion value (S120, S130). In one embodiment of the driving control method of the present invention, when performing automatic braking, if it is determined that the risk of deviation is less than a second deviation criterion value which is greater than a first deviation criterion value (S120, S130), automatic braking is performed at a first deceleration (S140), and if it is determined that the risk of deviation is greater than or equal to the second deviation criterion value (S120, S130), automatic braking is performed at a second deceleration value which is higher than the first deceleration (S170).

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

[0025] According to the above aspect, when it is determined that the risk of deviation is greater than a first deviation reference value and less than a second deviation reference value, automatic braking is performed at a first deceleration, and when it is determined that the risk of deviation is greater than or equal to the second deviation reference value, automatic braking is performed at a second deceleration higher than the first deceleration. Therefore, compared with 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.

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

[0027] In the above description, in order to assist in understanding the present invention, the names and / or symbols used in the embodiments are added in parentheses to the components 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 attendant advantages of the present invention will be readily understood from the description of the embodiments of the present invention described while referring to the following drawings.

Brief Description of the Drawings

[0028] [Figure 1] It is a schematic configuration diagram showing an embodiment of a vehicle travel control device according to the present invention. [Figure 2]This is a flowchart corresponding to the lane departure and steering judgment control program in the first embodiment. [Figure 3] This is a flowchart corresponding to the automatic braking control program for lane departure prevention in the first embodiment. [Figure 4] This is a flowchart corresponding to the essential parts of the lane departure and steering judgment control program in the second embodiment. [Figure 5] This is a routine for determining whether or not the driver is in a state of distracted driving. [Figure 6] This diagram shows a situation where a vehicle is at risk of deviating from a road (an area where it is permitted to travel) into an area where it is not permitted to travel. [Modes for carrying out the invention]

[0029] The vehicle driving control device and driving control method according to embodiments of the present invention will be described in detail below with reference to the attached figures.

[0030] As shown in Figure 1, the driving control device 100 according to an embodiment of the present invention is applied to a vehicle 102 and includes a driver assistance ECU 10. The vehicle 102 is a vehicle capable of autonomous driving and is equipped with a drive ECU 20, a brake ECU 30, an electric power steering ECU 40, and a meter ECU 50. ECU stands for Electronic Control Unit, which has a microcomputer as its main component. In the following description, electric power steering will be referred to as EPS.

[0031] Each ECU's microcomputer includes a CPU, ROM, RAM, read / write non-volatile memory (N / M), and an interface (I / F). The CPU implements various functions by executing instructions (programs, routines) stored in ROM. Furthermore, these ECUs are interconnected via CAN (Controller Area Network) 104, enabling data exchange (communication). Therefore, detection values ​​from sensors (including switches) connected to a specific ECU are transmitted to other ECUs.

[0032] The driver assistance ECU 10 is a central control unit that performs driving control for driver assistance, such as lane departure prevention control and inter-vehicle distance control. In this embodiment, the driver assistance ECU 10 works in cooperation with other ECUs to perform lane departure prevention control, as will be described in detail later. The driving control in this embodiment is performed as part of the lane departure prevention control.

[0033] The driver assistance ECU 10 is connected to a camera sensor 12, a radar sensor 14, a monitor camera 16, and a switch 18. The camera sensor 12 and the radar sensor 14 each include multiple camera devices and multiple radar devices, respectively. 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] Each camera device of the camera sensor 12, although not shown in the figure, includes a camera unit that photographs the area around the vehicle 102 and a recognition unit that analyzes the image data obtained from the camera unit to recognize road markings, other vehicles, and other objects. The recognition unit supplies information about the recognized objects to the driver assistance ECU 10 at predetermined intervals.

[0035] Each radar device of the radar sensor 14 is equipped with a radar transceiver and a signal processing unit (not shown). The radar transceiver emits millimeter-wave radio waves (hereinafter referred to as "millimeter waves") and receives millimeter waves (i.e., reflected waves) reflected by three-dimensional objects (e.g., other vehicles, bicycles, etc.) within the emission range. The signal processing unit supplies information representing the distance between the vehicle and the three-dimensional object, the relative speed between the vehicle and the three-dimensional object, and the relative position (direction) of the three-dimensional object to the vehicle at predetermined 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 the transmission of the millimeter waves to the reception of the reflected waves. LiDAR (Light Detection And Ranging) may be used instead of or in addition to the radar sensor 14.

[0036] The monitor camera 16 is mounted on the dashboard or 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 of the driver's face image data to the driver assistance ECU 10 at predetermined intervals. Thus, the monitor camera 16 functions as a driver monitor camera.

[0037] The CPU of the driver assistance ECU 10 determines the driver's level of arousal based on image data of the driver's face, including the driver's eye closure rate per minute, eye opening status, blinking frequency, or eye movements. Level of arousal refers to the degree to which the driver is distracted and unsuitable for driving due to lack of sleep or other reasons. The method for determining the level of arousal is not particularly limited, and any method known in the art may be used. In addition, at least one of the driver's grip pressure on the steering wheel, pressure on the armrest, heart rate, electromyography information, and electroencephalogram pattern may be considered when determining the level of arousal.

[0038] Switch 18 is located in a position accessible to the driver, similar to a steering wheel (not shown in Figure 1), and is operated by the driver. When switch 18 is turned on, the driver assistance ECU 10 performs lane departure prevention control, as will be described in detail later.

[0039] The drive ECU 20 is connected to a drive unit 22 that accelerates the vehicle 102 by applying driving force to the drive wheels 24. Normally, the drive ECU 20 controls the drive unit 22 so that the driving force generated by the drive unit 22 changes in accordance with the driver's driving operation, and when it receives a command signal from the driver assistance ECU 10, it controls the drive unit 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 braking force to the wheels 34. Normally, the braking ECU 30 controls the braking device 32 so that the braking force generated by the braking device 32 changes in accordance with the braking operation by the driver. When it receives a command signal from the driver 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 work together to function as an automatic braking system 36. Note that when braking force is applied to the wheels by lane departure prevention control or the like, brake lights (not shown in Figure 1) illuminate.

[0042] The EPS / ECU 40 is connected to the EPS device 42. Based on the steering torque Ts and vehicle speed V detected by the driving operation sensor 60 and vehicle condition sensor 70 (described later), the EPS / ECU 40 controls the steering assist torque by controlling the EPS device 42 in a manner known in the art, thereby reducing the driver's steering burden. Furthermore, by controlling the EPS device 42, the EPS / ECU 40 can steer the steering wheels 44 as needed. Therefore, the EPS / ECU 40 and the EPS device 42 function as an automatic steering system that automatically steers the steering wheels as needed.

[0043] The meter ECU 50 is connected to a touch-panel display 52 that displays the control status by the driver assistance ECU 10 and a warning device 54 that issues warnings. The display 52 may be, for example, a multi-information display that displays meters and various other information, or it may be a display for a navigation system. When the display 52 receives a signal from the driver assistance ECU 10, it may display the status of the lane departure prevention control.

[0044] The warning device 54 is activated when it is determined that there is a risk of the vehicle 102 deviating off the road, and issues a warning as part of the lane departure prevention control, that is, a warning that there is a risk of the vehicle 102 deviating off the road. The warning device 54 may be any of the following: 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, or a warning device that emits a tactile warning such as seat vibration, or any combination thereof.

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

[0046] The driving operation sensor 60 includes a drive operation amount sensor for detecting the amount of operation of the accelerator pedal, a braking operation amount sensor for detecting master cylinder pressure or the force applied to the brake pedal, and a brake switch for detecting whether or not the brake pedal is operated. The driving operation sensor 60 also includes a steering angle sensor for detecting the steering angle θ, a steering torque sensor for detecting the steering torque Ts, and a turn signal switch for indicating whether or not the turn signal lever is operated and the direction of operation.

[0047] The vehicle condition sensor 70 includes a vehicle speed sensor for detecting the vehicle speed V of the vehicle 102, a longitudinal acceleration sensor for detecting the acceleration of the vehicle in the longitudinal direction, a lateral acceleration sensor for detecting the acceleration of the vehicle in the lateral direction, and a yaw rate sensor for detecting the yaw rate of the vehicle.

[0048] [First Embodiment] In the first embodiment, the ROM of the driver assistance ECU 10 stores a lane departure and steering determination control program corresponding to the flowchart shown in Figure 2. In the first embodiment, the ROM of the driver assistance ECU 10 also stores an automatic braking control program for lane departure suppression corresponding to the flowchart shown in Figure 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 Figures 2 and 3, respectively.

[0049] <Lane departure and steering detection and control (Figure 2)> Next, the lane departure and steering detection control in the first embodiment will be described with reference to the flowchart shown in Figure 2. The lane departure and steering detection control according to the flowchart shown in Figure 2 is repeatedly executed at predetermined intervals by the CPU of the driver assistance ECU 10 when switch 18 is ON. At the start of the lane departure and steering detection control, flag F is reset to 0.

[0050] First, in step S10, the CPU determines whether the absolute value of the steering torque Ts is greater than or equal to the reference value Tsc, that is, whether or not steering operations are being performed by the driver. If a negative determination is made, the control proceeds to step S60; if a positive determination is made, the control proceeds to step S20. The reference value Tsc may be a positive constant, and may be a positive value that is variably set according to the vehicle speed V such that it becomes smaller as the vehicle speed V increases.

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

[0052] In step S30, the CPU determines, for example, whether the direction of the driver's steering operation is such that the vehicle 102, as determined in step S20, will deviate off the road, based on the steering angle θ detected by the steering angle sensor and its change. If a negative determination is made, the control proceeds to step S60; if a positive determination is made, the control proceeds to step S40.

[0053] In step S40, the CPU determines whether the driver operated the turn signal lever in the direction corresponding to the steering direction determined in step S30, based on whether or not the turn signal lever, indicated by the turn signal switch, was operated and the direction of the operation. If the determination is positive, the control proceeds to step S60; if the determination is negative, the control proceeds to step S50.

[0054] In step S50, the CPU determines, for example, based on the target information around the vehicle 102 acquired by the target information acquisition device 15, whether the area ahead in the direction in which the vehicle 102 is likely to deviate off the road, as determined in step S20, is a non-traveling area, i.e., an area where the vehicle cannot travel. If a negative determination is made, in step S60, flag F is reset to 0, and if a positive determination is made, flag F is set to 1. A flag F of 1 indicates that there is a risk of the vehicle 102 deviating off the road and that control is needed to suppress the deviation.

[0055] <Automatic braking control for lane departure prevention (Figure 3)> Next, the braking force control for lane departure prevention in the first embodiment will be described with reference to the flowchart shown in Figure 3. The braking force control according to the flowchart shown in Figure 3 is repeatedly executed at predetermined intervals by the CPU of the driver assistance ECU 10 when the switch 18 is ON.

[0056] First, in step S110, the CPU determines whether flag F is 1 or not, that is, whether there is a risk of vehicle 102 deviating off the road and whether control is needed to suppress the deviation. If a negative determination is made, this control is terminated; if a positive 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, based on, for example, the target information around the vehicle 102 acquired by the target information acquisition device 15, in a manner known in the art. Furthermore, 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 of the vehicle deviating off the road is greater than or equal to the first reference value. If a negative determination is made, this control is terminated; if a positive determination is made, this control proceeds to step S130. Note that the time Te may be calculated, for example, as the time until the vehicle's preset reference position reaches the boundary between the road and the off-road area, based on the vehicle's lateral velocity.

[0058] In step S130, the CPU determines whether time Te is less than or equal to a second reference time Tec2 (a positive constant smaller than Tec1), that is, whether the risk of the vehicle deviating off the road is greater than or equal to the second reference value. If the determination is positive, the control proceeds to step S150. If the determination is negative, that is, if the risk of the vehicle deviating off the road is determined to be greater than or equal to the first reference value but less than the second reference value, the control proceeds to step S140.

[0059] In step S140, the CPU outputs a command signal to the braking ECU 30, thereby performing gradual braking control by automatic braking using the automatic braking device 36 so that the deceleration Gb of the vehicle 102 becomes the first deceleration Gb1 (a positive constant with the deceleration direction as positive). The CPU also outputs a command signal to the meter ECU 50, which causes the buzzer device to emit an intermittent beeping alarm.

[0060] In step S150, the CPU determines whether or not the driver performed a braking operation based on the detection result of the braking operation amount sensor or the status of the brake switch. If the determination is positive, this control is terminated; if the determination is negative, this control proceeds to step S160.

[0061] In step S160, the CPU determines, for example, whether the driver is steering the vehicle 102 in the opposite direction to the direction in which it would deviate off the road, based on the steering angle θ detected by the steering angle sensor and its change. If the determination is positive, this control is terminated; if the determination is negative, this control proceeds to step S170. If the driver is not steering, a negative determination is made.

[0062] In step S170, the CPU outputs a command signal to the braking ECU 30, thereby performing forced braking control by the automatic braking device 36 so that the deceleration Gb of the vehicle 102 becomes a second deceleration Gb2 (a positive constant greater than Gb1). The CPU also outputs a command signal to the meter ECU 50, which causes the buzzer device to emit a continuous sound alarm.

[0063] [Second Embodiment] In the second embodiment, the ROM of the driver assistance ECU 10 stores a lane departure and steering determination control program corresponding to the flowchart whose main parts are shown in Figure 4. The automatic braking control program for lane departure prevention in the second embodiment is the same as the automatic braking control program for lane departure prevention 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 prevention according to the flowcharts shown in Figures 4 and 3, respectively.

[0064] <Lane departure and steering detection and control (Figure 4)> As shown in Figure 4, steps S2 and S4 or steps S2 and S6 are performed prior to step S10, and steps S10 to S70 are performed in the same manner as in the first embodiment.

[0065] In step S2, the CPU determines whether the driver is in a state of distracted driving. If the determination is negative, in step S4, the reference value Tsc used for the determination in step S10 is set to the standard reference value Tscn. Conversely, if the determination is positive, in step S6, the reference value Tsc is set to the reference value Tscs for distracted driving, which is smaller than the standard reference value Tscn. Once step S4 or S6 is completed, the control proceeds to step S10. Note that the reference values ​​Tscn and Tscs may be positive constants, and may be positive values ​​that are variably set according to the vehicle speed V such that they become smaller as the vehicle speed V increases.

[0066] <Determination of distracted driving> The determination of whether or not the driver is in a state of distracted driving may be made in any manner known in the art, based on 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 Figure 5.

[0067] In step S210, the CPU determines whether the driver's eyes are closed or not. If the determination is positive, the control proceeds to step S250; if the determination is negative, the control proceeds to step S220.

[0068] In step S220, the CPU determines whether the driver is distracted. If the determination is positive, the control proceeds to step S250; if the determination is negative, the control proceeds to step S230. Note that the driver may be determined to be distracted if the time and frequency of the driver's gaze not being directed towards the front of the vehicle are equal to or greater than the corresponding standard values.

[0069] In step S230, the CPU determines whether the driver is drowsy. If a negative determination is made, in step S240, it is determined that the driver is not in a state of distracted driving. If a positive determination is made, in step S250, it is determined that the driver is in a state of distracted driving. In addition, if the driver's gaze is directed downwards rather than forward, or if the frequency of the driver's blinking and yawning exceeds the corresponding standard values, it may be determined that the driver is drowsy.

[0070] <Effects of the First and Second Embodiments> As mentioned above, even if the driver steers the vehicle in a situation where there is a risk of the vehicle deviating off the road, if the direction of the steering operation is such that it causes the vehicle to deviate off the road, the steering operation may not be considered an operation performed by the driver to actively control the direction of travel 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 of the vehicle deviating off the road (S10), and it is determined that the steering operation was performed in the direction that would cause the vehicle to deviate off the road (S30), automatic braking is performed. Therefore, compared to conventional driving control devices, in which automatic braking is not performed regardless of the steering direction when a steering operation is performed, the risk of the vehicle deviating off the road can be reduced.

[0072] For example, Figure 6 shows a situation in which there is a risk that the vehicle 102 may deviate from the road 104, which is a drivable area, into the area 106, which is an area where it is not drivable. In particular, Figure 6(A) shows a situation in which the driver is operating the steering wheel 108 in a direction away from the area 106 where it is not drivable, and Figure 6(B) shows a situation in which the driver is operating the steering wheel 108 in a direction toward the area 106 where it is not drivable.

[0073] In the situation shown in Figure 6(A), a positive determination is made in step S20, but a negative determination is made in step S30, and 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. Thus, when the driver is trying to prevent the vehicle from veering off the road by steering, unnecessary automatic braking and warning issuance can be avoided.

[0074] In contrast, in the situation shown in Figure 6(B), a positive determination is made in steps S20 and S30, and flag F is set to 1 in step S70. Therefore, a positive determination is made in step S110, so steps S140 and S170 are executed, and automatic braking and warning are issued. Thus, the driver's attention is drawn and the vehicle is slowed down, reducing the risk of the vehicle 102 deviating into the area 106 where it cannot be driven.

[0075] Furthermore, the risk of vehicle 102 deviating off the road is reduced by the vehicle's automatic braking and the issuance of warnings (S140, S170), and automatic steering operations that counteract the driver's steering operations, i.e., automatic steering of the steering wheels, are not performed. Therefore, even if a situation arises in which the direction in which the vehicle deviates off the road and / or the direction of the steering operation cannot be properly determined, this will not result in inappropriate automatic steering operations, and thus the direction of travel of the vehicle will not be inappropriately controlled.

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

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

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

[0079] Therefore, compared to a situation where the steering reference value is constant regardless of whether the driver is driving distractedly or not, it is possible to properly determine whether or not the driver performed a steering operation based on the relevant values ​​of the steering operation, even when the driver is driving distractedly.

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

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

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

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

[0084] 10…Driver assistance ECU, 12…Camera sensor, 14…Radar sensor, 15…Target information acquisition device, 16…Monitor camera, 22…Drive system, 32…Braking system, 36…Automatic braking system, 100…Driving control device, 102…Vehicle

Claims

1. A vehicle driving control device comprising: a steering operation detection device for detecting the driver's steering operation; a target information acquisition device for acquiring information on targets around the vehicle; an automatic braking device for automatically braking the vehicle; and a control unit for controlling the automatic braking device, wherein the control unit is configured to perform automatic braking by activating the automatic braking device when it determines, based on the target information acquired by the target information acquisition device, that there is a risk of the vehicle deviating off the road, and when it determines, based on the steering operation detected by the steering operation detection device, that the vehicle has been steered in a direction that would cause it to deviate off the road, The aforementioned driving control device further includes a driving state information acquisition device that acquires information on the driver's driving state, A vehicle driving control device configured such that the control unit determines whether the driver's driving state is a state of distracted driving based on the driving state information acquired by the driving state information acquisition device, and when it is determined that the driver's driving state is not a state of distracted driving, it performs the automatic braking when it is determined that the risk of deviation is greater than or equal to a first deviation criterion value and the related value of the steering operation is greater than or equal to a first steering criterion value, and when it is determined that the driver's driving state is a state of distracted driving, it performs the automatic braking when it is determined that the risk of deviation is greater than or equal to the first deviation criterion value and the related value of the steering operation is greater than or equal to a second steering criterion value which is smaller than the first steering criterion value.

2. A vehicle driving control device according to claim 1, wherein the control unit is configured to perform the automatic braking at a first deceleration when it determines that the likelihood of deviation is less than a second deviation criterion value which is greater than the first deviation criterion value, and to perform the automatic braking at a second deceleration value which is higher than the first deceleration when it determines that the likelihood of deviation is greater than or equal to the second deviation criterion value.

3. The process includes the steps of: acquiring information on landmarks around the vehicle; determining whether there is a risk of the vehicle deviating off the road based on the acquired landmark information; and, if it is determined that there is a risk of deviation, activating the automatic braking system to automatically brake the vehicle. Furthermore, in the vehicle driving control method, if the driver's steering operation is detected and it is determined that there is a risk of the vehicle deviating from the road, but it is determined that the steering operation was performed in a direction other than the direction in which the vehicle would deviate off the road, the automatic braking will not be performed, and if it is determined that there is a risk of the vehicle deviating from the road and it is determined that the steering operation was performed in the direction in which the vehicle would deviate off the road, the automatic braking will be performed. A vehicle driving control method that determines whether the driver's driving state is a state of distracted driving based on driving state information acquired by a driving state information acquisition device that acquires information on the driver's driving state, and when it is determined that the driver's driving state is not a state of distracted driving, and when it is determined that the risk of deviation is greater than or equal to a first deviation criterion value and the related value of the steering operation is greater than or equal to a first steering criterion value, the automatic braking is performed, and when it is determined that the driver's driving state is a state of distracted driving, and when it is determined that the risk of deviation is greater than or equal to the first deviation criterion value and the related value of the steering operation is greater than or equal to a second steering criterion value which is smaller than the first steering criterion value, the automatic braking is performed.

4. A vehicle driving control method according to Claim 3, wherein when performing automatic braking, if it is determined that the risk of deviation is less than a second deviation criterion value which is greater than the first deviation criterion value, the automatic braking is performed at the first deceleration, and if it is determined that the risk of deviation is equal to or greater than the second deviation criterion value, the automatic braking is performed at a second deceleration which is higher than the first deceleration.

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