Vehicle travel control device and method

Abstract

The invention provides a vehicle travel control apparatus and method. The vehicle travel control device includes a driving support ECU configured to execute a possibility reduction control for reducing a possibility when it is determined that there is a possibility that the host vehicle collides with an object to be controlled present ahead of the host vehicle in a traveling direction, and to execute a possibility reduction control for reducing the possibility when it is determined that there is a possibility that the host vehicle collides with the object to be controlled present ahead of the host vehicle in the traveling direction. The driving assistance ECU performs override control that suppresses execution of possibility reduction control on the basis of a driving operation by a driver of the host vehicle, and performs override control that suppresses execution of possibility reduction control on the basis of a driving operation by the driver of the host vehicle. At least one of a process in which the possibility reduction control becomes easy to execute and a process in which the override control becomes difficult to execute is performed is performed.

Description

Technical Field

[0001] The present invention relates to a driving control device and method for a vehicle such as a motor vehicle, and more particularly, to a driving control device and method for reducing the possibility of a vehicle colliding with a control object. Background Art

[0002] As one of the driving control devices, there is known a driving control device that, when there is a possibility of the host vehicle colliding with a control object, reduces the possibility of collision by using a possibility reduction control implemented by automatic braking and alarm of the host vehicle, and performs an override control that suppresses the execution of the possibility reduction control when a driving operation such as acceleration is performed by the driver.

[0003] The following driving control device is described in Japanese Unexamined Patent Application Publication No. 2021-37804: an override control that switches whether to execute the override control that suppresses the execution of the possibility reduction control according to whether the control object is another vehicle or the like, or the control object is a pedestrian or a bicycle. Summary of the Invention

[0004] In a situation where possibility reduction control is performed, it is not easy to "determine whether a driving operation such as acceleration is a driving operation based on the driver's intention or a misoperation or a negligent driving operation". For example, in a situation where the preceding vehicle and the host vehicle have stopped, the host vehicle sometimes starts negligently as the vehicle in the adjacent lane starts. In such a situation, if it is determined that the starting driving operation is a driving operation based on the driver's intention, the possibility reduction control is not performed, and thus, the possibility of the host vehicle colliding with the preceding vehicle cannot be reduced.

[0005] The present invention provides a driving control device and method that are improved to "reduce the possibility of the host vehicle colliding with the preceding vehicle even in a situation where the host vehicle starts negligently as the vehicle in the adjacent lane starts in a situation where the preceding vehicle and the host vehicle have stopped".

[0006] According to the present invention, there is provided a driving control device (100) for a vehicle, the driving control device including a control unit (driving assistance ECU 10), the control unit being configured to, when it is determined that there is a possibility of the host vehicle (102) colliding with a control object existing in front of the host vehicle in the traveling direction (S50), execute a possibility reduction control (S100, S130) for reducing the possibility, and execute an override control (S40, S60 to S80, S120) that suppresses the execution of the possibility reduction control based on a driving operation of the driver of the host vehicle.

[0007] The control unit (driving assistance ECU 10) is configured to perform at least one of a process that makes it easier to execute the likelihood reduction control and a process that makes it difficult to execute the override control (S60, S80) when it is determined that a lax start has occurred in which, although there is a preceding vehicle in a stationary state ahead of the host vehicle in the host lane, the host vehicle has started due to the start of another vehicle in an adjacent lane (S40).

[0008] Furthermore, according to the present invention, there is provided a method for controlling the running of a vehicle, the method for controlling the running including: a step of executing a likelihood reduction control for reducing the likelihood when it is determined that there is a likelihood of a collision between the host vehicle (102) and a control object ahead in the traveling direction of the host vehicle (S50); and a step of executing an override control for suppressing the execution of the likelihood reduction control based on the driving operation of the driver of the host vehicle (S40, S60 to S80, S120).

[0009] The method for controlling the running further includes: a step of determining whether a lax start has occurred in which, although there is a preceding vehicle in a stationary state ahead of the host vehicle in the host lane, the host vehicle has started due to the start of another vehicle in an adjacent lane (S40); and a step of performing at least one of a process that makes it easier to execute the likelihood reduction control and a process that makes it difficult to execute the override control when it is determined that a lax start has occurred (S60, S80).

[0010] According to the above-described running control device and method, when it is determined that a lax start has occurred, at least one of a process that makes it easier to execute the likelihood reduction control and a process that makes it difficult to execute the override control is performed. Therefore, in a case where a lax start has occurred in which, although there is a preceding vehicle in a stationary state ahead of the host vehicle in the host lane, the host vehicle has started due to the start of another vehicle in an adjacent lane, it is possible to "make it easier to execute the likelihood reduction control" and / or "make it difficult to execute the override control". Accordingly, even in a situation where the host vehicle starts laxly as a vehicle in an adjacent lane starts while the preceding vehicle and the host vehicle are stopped, it is possible to reduce the likelihood of a collision between the host vehicle and the preceding vehicle.

[0011] In one aspect of the present invention, the control unit (driving assistance ECU 10) is configured to make it easier to execute the likelihood reduction control by relaxing the execution conditions of the likelihood reduction control (S60, S80) when it is determined that a lax start has occurred (S40) as compared with when it is not determined that a lax start has occurred.

[0012] According to the above solution, when it is determined that a lazy start has occurred, compared with when it is not determined that a lazy start has occurred, the execution conditions of the mitigation possibility reduction control are relaxed. Therefore, compared with the case where the execution conditions of the mitigation possibility reduction control are not relaxed, the possibility reduction control can be made easier to execute.

[0013] In another solution of the present invention, the control unit (driving assistance ECU 10) is configured such that when it is determined that a lazy start has occurred (S40), compared with when it is not determined that a lazy start has occurred, the execution conditions of the override control are made stricter to make the override control difficult to execute (S60, S80).

[0014] According to the above solution, when it is determined that a lazy start has occurred, compared with when it is not determined that a lazy start has occurred, the execution conditions of the override control are made stricter. Therefore, compared with the case where the execution conditions of the override control are not made stricter, the override control can be made difficult to execute.

[0015] Moreover, in another solution of the present invention, the control unit (driving assistance ECU 10) is configured such that when the first condition (S41), the second condition (S42), and the third condition (S44) are satisfied, and when the host vehicle starts within the reference time from the establishment of the second condition (S43), it is determined that a lazy start has occurred (S40, S45). The first condition is that there is a stopped leading vehicle ahead within the range of the first distance from the host vehicle in the host lane. The second condition is that another vehicle stopped ahead within the range of the second distance from the host vehicle in the adjacent lane has started. The third condition is that there is no possibility of the host vehicle changing lanes out of the host lane.

[0016] According to the above solution, when the first to third conditions are satisfied, and when the host vehicle starts within the reference time from the establishment of the second condition, it is determined that a lazy start has occurred. The first condition is that there is a stopped leading vehicle ahead within the range of the first distance from the host vehicle in the host lane. The second condition is that another vehicle stopped ahead within the range of the second distance from the host vehicle in the adjacent lane has started. The third condition is that there is no possibility of the host vehicle changing lanes out of the host lane.

[0017] Therefore, compared with the case where any one of the first to third conditions is not used as a necessary condition or the case where "the host vehicle starts within the reference time from the establishment of the second condition" is not used as a necessary condition, the determination of "whether a lazy start has occurred" can be appropriately made.

[0018] In the above description, in order to facilitate understanding of the present invention, names and / or reference numerals used in the following embodiments are added in parentheses to the configurations of the invention corresponding to the following embodiments. However, each component of the present invention is not limited to the components of the embodiments corresponding to the names and / or reference numerals 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 with reference to the following drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Hereinafter, the features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the drawings, in which like reference numerals denote like elements, and in which:

[0020] Figure 1 is a schematic configuration diagram showing an embodiment of a travel control device for a vehicle of the present invention;

[0021] Figure 2 is a flowchart corresponding to a travel control program in the embodiment;

[0022] Figure 3 is shown in Figure 2 a flowchart of a loose start determination control routine executed in S40 of;

[0023] Figure 4 is a diagram showing a situation where the present vehicle, the preceding vehicle, and the adjacent vehicle stop in front of a crosswalk;

[0024] Figure 5 is shown in Figure 4 a diagram showing an example of changes in the vehicle speeds of the present vehicle, the preceding vehicle, and the adjacent vehicle in the situation shown; and

[0025] Figure 6A is a diagram showing a situation where the stopped present vehicle, preceding vehicle, and adjacent vehicle start almost simultaneously.

[0026] Figure 6B is a diagram showing a situation where the preceding vehicle maintains a stationary state, the stopped adjacent vehicle starts, and the present vehicle starts while changing lanes toward the adjacent vehicle side. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Hereinafter, a travel control device according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0028] As Figure 1As shown, the driving control device 100 of the embodiment of the present invention is applicable to a vehicle 102 and includes a driving assistance ECU 10. The vehicle 102 is a vehicle capable of autonomous driving and includes a drive ECU 20, a brake ECU 30, and an instrument ECU 50. An ECU refers to an electronic control unit (ECU: Electronic Control Unit) having a microcomputer as a main part. Regarding the vehicle 102, in order to distinguish it from other vehicles, it is referred to as the own vehicle 102 as needed.

[0029] The microcomputer of each ECU includes a CPU, a ROM, a RAM, a rewritable 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. Moreover, these ECUs are connected to each other via a controller area network (CAN: Controller Area Network) 104 in a manner capable of data exchange (capable of communication). Therefore, the detection values of sensors (including switches) connected to a specific ECU are also sent to other ECUs.

[0030] The driving assistance ECU 10 is a central control device for performing driving assistance such as driving control, following distance control, and lane keeping control. In the embodiment, the driving assistance ECU 10, as will be described in detail later, cooperates with other ECUs to execute driving control for the vehicle 102. In the embodiment, when the driving assistance ECU 10 determines that there is a possibility of collision between the own vehicle and a control object existing in front of the traveling direction of the own vehicle, it executes a likelihood reduction control for reducing the possibility. In addition, the driving assistance ECU 10 executes an override control for suppressing the execution of the likelihood reduction control based on the driving operation of the driver of the own vehicle.

[0031] A camera sensor 12, a radar sensor 14, and a setting operator 16 are connected to the driving assistance 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 an object information acquisition device 18 for acquiring object information around the vehicle 102.

[0032] Although not shown, each camera device of the camera sensor 12 includes a camera head for photographing the surroundings of the vehicle 102 and an identification unit for analyzing the image data photographed by the camera head to identify objects such as white lines on the road and other vehicles. The identification unit supplies information related to the identified object to the driving assistance ECU 10 at predetermined intervals.

[0033] Each radar device of the radar sensor 14 includes a radar transceiver unit and a signal processing unit (not shown). The radar transceiver unit 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 a three-dimensional object (e.g., another vehicle, a bicycle, etc.) existing within the emission range. The signal processing unit supplies information indicating the distance between the host vehicle and the three-dimensional object, the relative speed between the host vehicle and the three-dimensional object, the relative position (direction) of the three-dimensional object with respect to the host vehicle, etc. to the driving assistance ECU 10 at a predetermined time interval 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. In addition, instead of the radar sensor 14, or in addition to the radar sensor 14, a lidar (LiDAR: Light Detection And Ranging) may be used.

[0034] The setting operator 16 is provided at a position where it can be operated by the driver, such as a steering wheel not shown in Figure 1 and is operated by the driver. Although Figure 1 not shown in, the setting operator 16 includes a driving assistance switch. As will be described in detail later, the driving assistance ECU 10 executes driving control when the driving assistance switch is turned on.

[0035] A drive device 22 is connected to the drive ECU 20, and the drive device 22 accelerates the vehicle 102 by applying a driving force to the drive wheels 24. The drive ECU 20 normally controls the drive device 22 such that the driving force generated by the drive device 22 changes according to the driver's driving operation, and controls the drive device 22 based on the command signal when receiving the command signal from the driving assistance ECU 10.

[0036] A braking device 32 is connected to the braking ECU 30, and the braking device 32 decelerates the vehicle 102 by braking by applying a braking force to the wheels 34. The braking ECU 30 normally controls the braking device such that the braking force generated by the braking device 32 changes according to the driver's braking operation, and controls the braking device 32 based on the command signal when receiving the command signal from the driving assistance ECU 10, thereby performing automatic braking.

[0037] Therefore, the braking ECU 30 and the braking device 32 cooperate with each other to function as an automatic braking device 36. In addition, when a braking force is applied to the wheels through driving control or the like, Figure 1 a brake light not shown is lit.

[0038] The instrument ECU 50 is connected to a touch panel type display 52 that displays the status of the control of the driving assistance ECU 10 and an alarm device 54 that issues an alarm. The display 52 can be, for example, an instrument panel or a multi-functional information display that displays various types of information, or it can be the display of the navigation device 80 described later. As described below, when the display 52 receives a signal from the driving assistance ECU 10, it displays the status of the driving control.

[0039] The alarm device 54 operates when it is determined that there is a possibility of a collision between the vehicle 102 and a control object such as an obstacle, and issues an alarm as one of the likelihood reduction controls for reducing the likelihood of a collision, that is, issues an alarm indicating the possibility of a collision between the vehicle 102 and the control object. The alarm device 54 can be any one of an alarm device that issues a visual alarm such as an alarm lamp, an alarm device that issues an auditory alarm such as an alarm buzzer, or an alarm device that issues a tactile alarm such as the vibration of the seat, or any combination thereof.

[0040] The driving operation sensor 60 and the vehicle state sensor 70 are also connected to the CAN 104. The information detected by the driving operation sensor 60 and the vehicle state sensor 70 (referred to as sensor information) is sent to the CAN 104. The sensor information sent to the CAN 104 can be appropriately used in each ECU. In addition, the sensor information can also be the information of a sensor connected to a specific ECU and is sent from the specific ECU to the CAN 104.

[0041] The driving operation sensor 60 includes a drive operation amount sensor that detects the operation amount of the accelerator pedal, a brake 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. In addition, the driving operation sensor 60 includes a steering angle sensor that detects the steering angle, a steering torque sensor that detects the steering torque, and the like.

[0042] 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 acceleration in the longitudinal direction of the vehicle, a lateral acceleration sensor that detects the acceleration in the lateral direction of the vehicle, and a yaw rate sensor that detects the yaw rate of the vehicle, and the like.

[0043] Moreover, the navigation device 80 is also connected to the CAN 104. The navigation device 80 includes a GPS receiver that detects the position of the vehicle 102, a storage device that stores map information and road information, and a communication device that obtains the latest information of the map information and the road information from the outside. In particular, the road information can include information on locations where there is a possibility of the vehicle temporarily stopping, such as intersections and crosswalks. In addition, the navigation device 80 may not be provided.

[0044] In an embodiment, the ROM of the driving assistance ECU 10 stores a driving control program corresponding to the Figure 2 and Figure 3 flowchart shown.

[0045] Driving control ( Figure 2 )

[0046] Next, the driving control in the embodiment will be described with reference to the Figure 2 flowchart shown. Figure 2 The driving control of the flowchart shown is repeatedly executed by the CPU of the driving assistance ECU 10 at predetermined intervals in a state where the driving assistance switch is turned on. In addition, the flags Faoa, Faob, and Fas are initialized to 0 when starting the driving control.

[0047] First, in S10, the CPU determines whether the driver has performed an accelerator operation based on the operation amount of the accelerator pedal detected by the drive operation amount sensor of the driving operation sensor 60. When a positive determination is made, the flag Faoa is set to 1 in S20, and when a negative determination is made, the flag Faoa is set to 0 in S30. Faoa being 1 indicates that it is determined that the driver has performed an accelerator operation, and Faoa being 0 indicates that it is not determined that the driver has performed an accelerator operation. In addition, it may be determined that the driver has performed an accelerator operation when the accelerator opening is equal to or greater than the reference opening or when the accelerator opening speed is equal to or greater than the reference opening speed.

[0048] In S40, the CPU makes a determination of a sluggish start according to the Figure 3 routine shown later. As will be described in detail later, when it is determined that the own vehicle 102 has made a sluggish start, the flag Fas is set to 1, and when it is determined that the own vehicle 102 has not made a sluggish start, the flag Fas is reset to 0.

[0049] In S50, the CPU determines the presence or absence of the possibility of a collision between the own vehicle and the preceding vehicle based on, for example, the distance between the own vehicle and the preceding vehicle detected by the camera sensor 12 or the radar sensor 14 and the relative speed of the own vehicle with respect to the preceding vehicle. When it is determined that there is no possibility of a collision, this control is temporarily terminated, and when it is determined that there is a possibility of a collision, this control proceeds to S60.

[0050] In S60, the CPU determines whether the flag Fas is 1, that is, determines whether it is determined in S40 that the own vehicle 102 has made a sluggish start. When a positive determination is made, this control proceeds to S80, and when a negative determination is made, this control proceeds to S70.

[0051] In S70, the CPU sets the alarm reference value TTCa of the time to collision (TTC) for determining whether an alarm needs to be issued to the standard value TTCan (a positive constant), and sets the flag Faob to 1. In addition, the flag Faob being 1 means that the accelerator override is effective.

[0052] In S80, the CPU sets the alarm reference value TTCa of the time to collision (TTC) to a value TTCah (a positive constant) greater than the standard value TTCan, and resets the flag Faob to 0. In addition, the flag Faob being 0 means that the accelerator override is ineffective.

[0053] In S90, the CPU calculates the time to collision (TTC) as the predicted time until the vehicle 102 collides with the preceding vehicle. The time to collision (TTC) is calculated based on the distance Dr between the host vehicle and the preceding vehicle and the relative speed Vr of the host vehicle with respect to the preceding vehicle, based on the detection result of the target object information acquisition device 18, for example, according to the following formula (1). The time to collision (TTC) is an index indicating the likelihood of a collision between the host vehicle and the preceding vehicle. The smaller this value, the higher the likelihood (risk) of a collision between the host vehicle and the preceding vehicle.

[0054] TTC = Dr / Vr...(1)

[0055] Moreover, the CPU makes a determination of "whether the time to collision (TTC) is less than or equal to the alarm reference value TTCa", that is, a determination of "whether an alarm indicating the possibility of a collision between the host vehicle and the preceding vehicle needs to be issued". When a negative determination is made, this control determination proceeds to S140. When a positive determination is made, this control proceeds to S100.

[0056] In S100, the CPU outputs an instruction signal to the meter ECU 50, thereby displaying an alarm indicating the possibility of a collision between the host vehicle and the preceding vehicle on the display 52, and operating the alarm device 54 to issue an alarm indicating the possibility of a collision between the host vehicle and the preceding vehicle.

[0057] In S110, the CPU makes a determination of "whether the time to collision (TTC) is less than or equal to the automatic braking reference value TTCb", that is, a determination of "whether automatic braking based on the automatic braking device 36 needs to be performed to reduce the likelihood of a collision". When a negative determination is made, this control determination proceeds to S140. When a positive determination is made, this control proceeds to S120.

[0058] In S120, the CPU determines whether the flag Faoa or the flag Faob is 0. When a negative determination is made, this control determination proceeds to S140. When a positive determination is made, this control proceeds to S130.

[0059] In S130, the CPU outputs an instruction signal to the braking ECU 30, thereby braking the host vehicle by automatic braking based on the automatic braking device 36 to reduce the possibility of a collision.

[0060] In S140, the CPU determines whether the end condition of this control is satisfied. When a negative determination is made, this control determination returns to S90, and when a positive determination is made, this control temporarily ends.

[0061] Further, it may be that when any one of the following E1 to E3 is satisfied, it is determined that the end condition of this control is satisfied.

[0062] E1: There is no longer a possibility of a collision between the host vehicle and the preceding vehicle.

[0063] E2: The preceding vehicle has started moving.

[0064] E3: The host vehicle has changed lanes.

[0065] As can be seen from the above description, in the embodiment, the possibility reduction control for reducing the possibility of a collision between the host vehicle and the preceding vehicle is the issuance of an alarm by the operation of the alarm device 54 and the automatic braking by the automatic braking device 36.

[0066] Lazy start determination control ( Figure 3 )

[0067] Next, with reference to Figure 3 the flowchart shown, the lazy start determination control executed in S40 above will be described.

[0068] In S41, the CPU determines whether there is a preceding vehicle in a stationary state in the host lane (whether the first condition is satisfied). When a negative determination is made, this control proceeds to step 46, and when a positive determination is made, this control proceeds to S42.

[0069] Further, it may be that when all of the following A1 to A3 are satisfied, it is determined that there is a preceding vehicle in a stationary state in the host lane.

[0070] A1: The preceding vehicle is within the range of the host lane.

[0071] A2: The preceding vehicle is within the range of a reference distance (a positive constant) from the host vehicle.

[0072] A3: The preceding vehicle has stopped (is in a stopped state).

[0073] In S42, the CPU determines whether the vehicle stopped in the adjacent lane has started moving (whether the second condition is satisfied). If the determination is negative, this control proceeds to step 46. If the determination is positive, this control proceeds to S43.

[0074] Alternatively, it may be determined that the vehicle stopped in the adjacent lane has started moving when all of the following B1 to B4 are satisfied.

[0075] B1: In the previous cycle, the adjacent vehicle was within the range of the adjacent lane.

[0076] B2: In the previous cycle, the adjacent vehicle was within the reference range from the own vehicle. Additionally, the reference range may be a range that is a predetermined distance (positive constant) from the side of the own vehicle toward the front of the own vehicle.

[0077] B3: In the previous cycle, the adjacent vehicle was stopped.

[0078] B4: In the current cycle, the adjacent vehicle has advanced.

[0079] In S43, the CPU determines whether the own vehicle has started moving within the reference time since the second condition was satisfied. If the determination is negative, this control proceeds to step 46. If the determination is positive, this control proceeds to S44. Alternatively, it may be determined that the own vehicle has started moving when the own vehicle was stopped in the previous cycle and the own vehicle has advanced in the current cycle.

[0080] In S44, the CPU determines whether the exclusion condition for the scattered start determination is satisfied. If the determination is negative, in S45, it is determined that the start of the own vehicle is a scattered start, and the flag Fas is set to 1. In contrast, if the determination is positive, in S46, it is determined that the start of the own vehicle is not a scattered start, and the flag Fas is reset to 0.

[0081] Alternatively, it may be determined that the exclusion condition for the scattered start determination is satisfied when all of the following C1 to C3 are satisfied. In particular, "the following C1 and C2 are not satisfied" is the third condition that there is no possibility of the own vehicle 102 changing lanes out of the own lane.

[0082] C1: The turn signal is operated toward the adjacent vehicle side.

[0083] C2: The steering angle θ is at least the reference steering angle (positive constant) toward the adjacent vehicle side.

[0084] C3: The elapsed time since the adjacent vehicle started moving is at least the reference elapsed time (positive constant).

[0085] Operations and Effects of the Embodiment

[0086] The situation where this vehicle starts off in a sluggish manner ( Figure 4 , Figure 5 )

[0087] For example, Figure 4 shows a situation where the vehicle 102, the preceding vehicle 110, and the adjacent vehicle 112 stop in front of the crosswalk 114. The preceding vehicle 110 is in front of the vehicle 102 in the current lane 116, and the adjacent vehicle 112 is diagonally in front of the vehicle 102 in the adjacent lane 118. Although the preceding vehicle 110 remains stationary, as shown by the arrow, the stopped adjacent vehicle 112 starts moving, and accordingly, the vehicle 102 also starts moving.

[0088] In Figure 4 the situation shown, a positive determination is made in S41 to S43, a negative determination is made in S44, and the flag Fas is set to 1 in S45. In addition, positive determinations are made in S10, S50, and S60. Therefore, in S80, the alarm reference value TTCa for the time to collision TTC is set to a value TTCah larger than the standard value TTCan, and the flag Faob is reset to 0.

[0089] Therefore, it becomes easier to make a positive determination in S90, and thus, the alarm in S100 is issued earlier. In addition, after a positive determination is made in S110 and then a positive determination is made in S120, the automatic braking in S130 is not prohibited but executed, and the vehicle 102 is automatically braked to prevent a collision with the preceding vehicle 110.

[0090] Figure 5 shows Figure 4 an example of the changes in the vehicle speed, etc. of the vehicle 102, the preceding vehicle 110, and the adjacent vehicle 112 in the situation shown.

[0091] In Figure 5 , the adjacent vehicle 112 starts moving at time point t1, and at time point t2, the driver of the vehicle 102 steps on the accelerator pedal to start increasing the accelerator opening, and immediately thereafter, the vehicle 102 starts moving.

[0092] At time point t3 immediately after the vehicle 102 starts moving, the flag Fas is set to 1, and by executing S80, the alarm reference value TTCa for the time to collision TTC is set to a value TTCah larger than the standard value TTCan, and the flag Faob is reset to 0. Therefore, the alarm is issued at time point t4, which is earlier than time point t5 when the alarm is started in the case where the flag Fas is 0.

[0093] In addition, at time point t6, the driver of the vehicle 102 further steps on the accelerator pedal and the accelerator opening increases. At time point t7 immediately after that, the determination in S110 becomes an affirmative determination. Since an affirmative determination is made in S120, S130 is executed, and the vehicle 102 is automatically braked to prevent a collision with the preceding vehicle 110.

[0094] In addition, in the conventional driving control device, S40 and S60 to S80 are not executed. In S120, it is determined whether the flag Faoa is 0, and the determination of whether the flag Faob is 0 is not performed.

[0095] Therefore, when the determination in S110 becomes an affirmative determination, a negative determination is made in S120, and S130 is not executed. Thus, as Figure 5 shown by the dotted line, even when it reaches time point t7, the vehicle 102 does not perform automatic braking. Therefore, a collision between the vehicle and the preceding vehicle 110 cannot be prevented.

[0096] Case where the preceding vehicle also starts ( Figure 6A )

[0097] Figure 6A As shown by the arrow, the stopped vehicle 102, the preceding vehicle 110, and the adjacent vehicle 112 start almost simultaneously.

[0098] In Figure 6A the shown situation, a negative determination is made in S41, and the flag Fas is reset to 0 in S46. Therefore, even if an affirmative determination is made in S10, a negative determination is made in S60. Thus, in S70, the reference value TTCa of the collision prediction time TTC is set to the standard value TTCan, and the flag Faob is set to 1.

[0099] Since the collision prediction time TTC does not become a small value, a negative determination is made in S90, and the issuance of an alarm (S100) and automatic braking (S130) are not performed. In addition, since the reference value TTCa is set to the standard value TTCan, even if an affirmative determination is made in S90, the issuance of an alarm will not start in advance. Moreover, even if an affirmative determination is made in S90, a negative determination is made in S120, so the automatic braking of the vehicle is not performed.

[0100] Case where the vehicle changes lanes ( Figure 6B )

[0101] Figure 6B It shows a situation where the preceding vehicle 110 remains stationary, the adjacent vehicle 112 that has stopped starts as shown by the arrow, and the vehicle 102 starts while changing lanes toward the adjacent vehicle 112 side.

[0102] In Figure 6B the case of the situation shown, a positive determination is made in S41 to S44, and the flag Fas is reset to 0 in S46. Therefore, even if a positive determination is made in S10, a negative determination is made in S60. Thus, in S70, the reference value TTCa of the collision prediction time TTC is set to the standard value TTCan, and the flag Faob is set to 1.

[0103] Therefore, similar to the case of Figure 6A , the issuance of an alarm (S100) and automatic braking (S130) are not performed. Additionally, even if a positive determination is made in S90, the issuance of the alarm does not start prematurely. Moreover, even if a positive determination is made in S90, a negative determination is made in S120, so the automatic braking of the own vehicle is not performed.

[0104] From the above description, it can be seen that according to the driving control device and method of the present invention, when it is determined that a lax start has occurred (S40), at least one of the process that makes the likelihood reduction control easier to execute and the process that makes the override control difficult to execute (S60, S80) is performed. Thus, in the case of a lax start in which although there is a preceding vehicle in a stationary state ahead of the own vehicle in the same lane, the own vehicle is induced to start by the start of another vehicle in the adjacent lane, it is possible to achieve "making the likelihood reduction control easier to execute" and / or "making the override control difficult to execute". Therefore, even in a situation where the own vehicle starts laxly as the vehicle in the adjacent lane starts while the preceding vehicle and the own vehicle are stopped, the possibility of collision between the own vehicle and the preceding vehicle can be reduced.

[0105] In addition, according to the driving control device and method of the present invention, when it is determined that a lax start has occurred (S40), the execution conditions of the likelihood reduction control (S60, S80) are relaxed compared to when it is not determined that a lax start has occurred. Thus, compared to the case where the execution conditions of the likelihood reduction control are not relaxed, the likelihood reduction control can be made easier to execute.

[0106] In addition, according to the driving control device and method of the present invention, when it is determined that a lax start has occurred (S40), the execution conditions of the override control are made stricter (S60, S80) compared to when it is not determined that a lax start has occurred. Thus, compared to the case where the execution conditions of the override control are not made stricter, the override control can be made difficult to execute.

[0107] Moreover, according to the driving control device and method of the present invention, when the host vehicle starts within the reference time from the establishment of the second condition in a situation where the first to third conditions are established, it is determined that a lax start has been performed (S40, S45). The first condition is that there is a stopped leading vehicle ahead within a first distance from the host vehicle in the host lane (S41). The second condition is that another vehicle stopped ahead within a second distance from the host vehicle in the adjacent lane has started (S42). The third condition is that there is no possibility of the host vehicle changing lanes out of the host lane (S44). Therefore, compared with the case where any one of the first to third conditions is not set as a necessary condition or the case where "the host vehicle starts within the reference time from the establishment of the second condition" is not set as a necessary condition, it is possible to appropriately determine "whether a lax start has been performed".

[0108] As described above, for the present invention, specific embodiments have been described in detail. However, the present invention is not limited to the above-described embodiments, and it is obvious to those skilled in the art that various other embodiments can be implemented within the scope of the present invention.

[0109] For example, in the above-described embodiment, when it is determined that a lax start in which the host vehicle starts due to the start of another vehicle existing in the adjacent lane has been performed, both a process that makes it easier to execute the possibility reduction control and a process that makes it difficult to execute the override control are performed. That is, in S80, the alarm reference value TTCa is set to a value TTCah larger than the standard value TTCan, and the flag Faob is reset to 0. However, it is also possible to perform only one of the process that makes it easier to execute the possibility reduction control and the process that makes it difficult to execute the override control.

[0110] In addition, in the above-described embodiment, the possibility reduction control is the issuance of an alarm (S100) and automatic braking (S130). However, the possibility reduction control may be either the issuance of an alarm or automatic braking, and may include, in addition to the issuance of an alarm and / or automatic braking, an automatic steering for reducing the possibility of the host vehicle colliding with the leading vehicle.

[0111] In addition, in the above-described embodiment, when it is determined that a lax start has been performed (S40), the execution conditions of the possibility reduction control are relaxed by setting the alarm reference value TTCa to a value TTCah larger than the standard value TTCan (S60, S80). However, for example, the execution conditions of the possibility reduction control may be relaxed by other means such as reducing and correcting the automatic braking reference value TTCb.

[0112] Moreover, in the above-described embodiment, the override control that suppresses the execution of the suppression possibility reduction control is executed based on the accelerator operation (S10) of the driver of the host vehicle. However, the override control can be executed based on driving operations such as braking operations and steering operations in addition to the accelerator operation of the driver of the host vehicle.

Claims

1. A driving control device for a vehicle, The driving control device includes a control unit, The control unit is configured to perform likelihood reduction control for reducing the likelihood when it is determined that there is a likelihood of a collision between the host vehicle and a control object existing in front of the host vehicle in the traveling direction, and perform override control for suppressing the execution of the likelihood reduction control based on the driving operation of the driver of the host vehicle. The control unit is configured to perform at least one of a process that makes the likelihood reduction control easier to execute and a process that makes the override control more difficult to execute when it is determined that a lax start has occurred in which, although there is a preceding vehicle in a stationary state in front of the host vehicle in the same lane, the host vehicle starts due to the start of another vehicle in an adjacent lane.

2. The driving control device for a vehicle according to claim 1, The control unit is configured to make the likelihood reduction control easier to execute by relaxing the execution conditions of the likelihood reduction control when it is determined that the lax start has occurred, as compared with when it is not determined that the lax start has occurred.

3. The driving control device for a vehicle according to claim 1, The control unit is configured to make the override control more difficult to execute by making the execution conditions of the override control stricter when it is determined that the lax start has occurred, as compared with when it is not determined that the lax start has occurred.

4. The driving control device for a vehicle according to claim 1, The control unit is configured to determine that the lax start has occurred when the host vehicle starts within a reference time from the establishment of the second condition under the condition that the first condition, the second condition, and the third condition are established. The first condition is a condition that there is a stopped preceding vehicle in front of the host vehicle within a first distance from the host vehicle in the same lane. The second condition is a condition that another vehicle stopped in front within a second distance from the host vehicle in the adjacent lane has started. The third condition is a condition that there is no possibility of the host vehicle changing lanes out of the same lane.

5. A driving control method for a vehicle, comprising: A step of performing likelihood reduction control for reducing the likelihood when it is determined that there is a likelihood of a collision between the host vehicle and a control object existing in front of the host vehicle in the traveling direction; And a step of performing override control for suppressing the execution of the likelihood reduction control based on the driving operation of the driver of the host vehicle. The driving control method further includes: A step of determining whether a lax start has occurred in which, although there is a preceding vehicle in a stationary state in front of the host vehicle in the same lane, the host vehicle starts due to the start of another vehicle in an adjacent lane; and a step of performing at least one of a process that makes the likelihood reduction control easier to execute and a process that makes the override control more difficult to execute when it is determined that the lax start has occurred.

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