Travel control apparatus for vehicle, travel control method for vehicle, and program of the same

Abstract

To provide a method capable of reducing a possibility that a driver feels anxiety due to cutting-in of another vehicle, by changing an inter-vehicle distance during execution of follow-up inter-vehicle distance control to an appropriate distance.SOLUTION: While executing follow-up inter-vehicle distance control, a travel control apparatus for a vehicle determines whether there is occurrence of a specific situation where there is a possibility that an adjacent-lane following vehicle (AF) cuts in between an own vehicle (HV) and a follow-up object vehicle (an own-lane preceding vehicle) (PV), on the basis of a vehicle speed (Vh) of the own vehicle (HV), a vehicle speed (Vaf) of the adjacent-lane following vehicle (AF), a vehicle speed (Vap) of an adjacent-lane preceding vehicle (AP), and a distance (Da) from the own vehicle (HV) to the adjacent-lane preceding vehicle (AP). When determining that there is the occurrence of the specific situation, the travel control apparatus shortens a target inter-vehicle distance if a shortening condition of the target inter-vehicle distance is satisfied, and extends the target inter-vehicle distance if an extending condition of the target inter-vehicle distance is satisfied.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a vehicle cruise control device that performs adaptive vehicle distance control, a vehicle cruise control method, and a program therefor. [Background technology]

[0002] Conventionally, there have been known vehicle cruise control devices that perform adaptive cruise control to cause a vehicle to follow a preceding vehicle (i.e., a vehicle to be followed) traveling immediately in front of the vehicle so as to maintain a predetermined target inter-vehicle distance between the vehicle and the preceding vehicle. One such cruise control device (hereinafter referred to as a "conventional device") determines that another vehicle has cut in between the vehicle and the preceding vehicle when it detects a sudden decrease in the inter-vehicle distance during the execution of adaptive cruise control. The conventional device stops adaptive cruise control when it determines that the frequency of cut-ins is high. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-262960 Summary of the Invention

[0004] However, when the target inter-vehicle distance is set to a relatively long distance, other vehicles may frequently cut in. Therefore, conventional devices may frequently stop the adaptive inter-vehicle distance control. In contrast, if the cruise control device is configured to continue the adaptive inter-vehicle distance control even when the frequency of cut-ins increases, the inter-vehicle distance between the host vehicle and the preceding vehicle (i.e., the cutting-in vehicle) will frequently become short, and the host vehicle will be forced to suddenly decelerate every time a cut-in occurs. As a result, the driver of the host vehicle may feel uneasy.

[0005] The present invention has been made to solve the above-mentioned problems. That is, one object of the present invention is to provide a vehicle driving control device, a vehicle driving control method, and a program therefor that can reduce the possibility that a driver will feel uneasy due to another vehicle cutting in by changing the inter-vehicle distance to an appropriate distance while adaptive inter-vehicle distance control is being executed.

[0006] One aspect of the vehicle driving control device of the present invention is a vehicle driving control device equipped with a controller (10) capable of performing follow-up inter-vehicle distance control, which causes the host vehicle (HV) to drive so that the inter-vehicle distance (Dh) between the host vehicle and a vehicle to be followed (PV) traveling immediately in front of the host vehicle is maintained at a predetermined target inter-vehicle distance (Dtgt).

[0007] The controller During execution of the following inter-vehicle distance control, if a specific situation occurs in which there is a following vehicle (AF) in the adjacent lane (AL) adjacent to the own vehicle (HL) in which the own vehicle is traveling and there is a possibility that the following vehicle (AF) in the adjacent lane may cut in between the own vehicle (HV) and the vehicle to be followed (PV) (step 525: Yes), the target inter-vehicle distance is changed (step 535, step 550).

[0008] Therefore, if the cruise control device of the above aspect shortens the target inter-vehicle distance when a specific situation occurs, the possibility of a rear vehicle in an adjacent lane cutting in between the host vehicle and the vehicle to be followed can be reduced.Furthermore, if the cruise control device of the above aspect lengthens the target inter-vehicle distance when a specific situation occurs, even if a rear vehicle in an adjacent lane cuts in between the host vehicle and the vehicle to be followed, the inter-vehicle distance between the cutting in vehicle and the host vehicle can be made relatively large, thereby reducing the possibility of the host vehicle suddenly decelerating.Therefore, the possibility of the driver feeling uneasy can be reduced.

[0009] In the above aspect, the controller The system is configured to determine that the specific situation has occurred when a first relative speed condition (Vaf>Vh) is met, whereby at least the vehicle speed (Vaf) of the rear vehicle in the adjacent lane is higher than the vehicle speed (Vh) of the host vehicle (step 525).

[0010] If the vehicle speed of the vehicle behind in the adjacent lane is higher than the vehicle speed of the host vehicle, the vehicle behind in the adjacent lane may overtake the host vehicle and then cut in between the host vehicle and the vehicle to be followed. Therefore, according to the above aspect, it is possible to easily determine that a specific situation has occurred.

[0011] In the above aspect, the controller In addition to the first relative speed condition, when a second relative speed condition (Vap≦Vh) is met, in which an adjacent lane leading vehicle (AP) is present in the adjacent lane traveling immediately before the adjacent lane rear vehicle and the vehicle speed (Vap) of the adjacent lane leading vehicle (AP) is equal to or lower than the vehicle speed (Vh) of the host vehicle, the specific situation is determined to have occurred (step 525).

[0012] When a preceding vehicle in the adjacent lane, which is slower than the host vehicle, is traveling just before the following vehicle in the adjacent lane, the following vehicle may cut in between the host vehicle and the following target vehicle to overtake the preceding vehicle in the adjacent lane. Therefore, according to the above aspect, it is possible to easily determine that a specific situation has occurred.

[0013] In the above aspect, the controller In addition to the first relative speed condition and the second relative speed condition, when a first inter-vehicle distance condition (Da≧C1th) is met, which means that the distance (Da) from the host vehicle (HV) to the preceding vehicle (AP) in the adjacent lane is equal to or greater than a first threshold distance (C1th), the specific situation is determined to have occurred (step 525).

[0014] When the distance from the host vehicle to the preceding vehicle in the adjacent lane is equal to or greater than the first threshold distance, the possibility that the following vehicle in the adjacent lane will cut in between the host vehicle and the following target vehicle is higher than when the distance from the host vehicle to the preceding vehicle in the adjacent lane is less than the first threshold distance. Therefore, according to the above aspect, it is possible to easily determine that a specific situation has occurred.

[0015] In the above aspect, the controller If it is determined that the specific situation has occurred (step 525: Yes), and at least when a second inter-vehicle distance condition is met (step 530: Yes), that is, the distance (Da) from the vehicle to the preceding vehicle in the adjacent lane is equal to or less than a second threshold distance (C2th) that is longer than the first threshold distance (C1th), the target inter-vehicle distance is shortened (step 535).

[0016] When the second inter-vehicle distance condition (Da≦C2th) is met in addition to the first inter-vehicle distance condition (C1th≦Da), if a rear vehicle in the adjacent lane actually cuts in between the host vehicle and the vehicle to be followed, the inter-vehicle distance between the host vehicle and the cutting-in rear vehicle in the adjacent lane will be very short, which could cause the host vehicle to suddenly decelerate. Therefore, when the second inter-vehicle distance condition (Da≦C2th) is met in addition to the first inter-vehicle distance condition (C1th≦Da), the above-described aspect shortens the target inter-vehicle distance, thereby reducing the possibility that a rear vehicle in the adjacent lane will cut in between the host vehicle and the vehicle to be followed. As a result, the frequency with which the host vehicle is suddenly decelerated decreases, thereby reducing the possibility that the driver of the host vehicle will feel uneasy.

[0017] In the above aspect, the controller If it is determined that the specific situation has occurred (step 525: Yes), and at least when the third inter-vehicle distance condition is met (step 545: Yes), that is, the distance (Da) from the vehicle to the preceding vehicle in the adjacent lane is longer than the second threshold distance (C2th) which is longer than the first threshold distance (C1th), the target inter-vehicle distance is increased (step 550).

[0018] When the third inter-vehicle distance condition (Da>C2th) is met, there is a high possibility that a rear vehicle in the adjacent lane will cut in between the host vehicle and the vehicle to be followed. Therefore, in this case, the above-mentioned embodiment increases the target inter-vehicle distance. Therefore, even if a rear vehicle in the adjacent lane actually cuts in between the host vehicle and the vehicle to be followed, the inter-vehicle distance between the host vehicle and the rear vehicle in the adjacent lane that has cut in will not be very short. As a result, the host vehicle will not be suddenly decelerated, and the rear vehicle in the adjacent lane can cut in smoothly between the host vehicle and the vehicle to be followed, preventing the driver of the host vehicle from feeling uneasy.

[0019] In the above aspect, the controller If it is determined that the specific situation has occurred (step 525: Yes), A second inter-vehicle distance condition that the distance (Da) from the host vehicle to the preceding vehicle in the adjacent lane is equal to or less than a second threshold distance (C2th) that is longer than the first threshold distance (C1th); and a third relative speed condition that the vehicle speed (Vaf) of the rear vehicle in the adjacent lane is lower than a vehicle speed (Vh+Vth) obtained by adding a predetermined vehicle speed threshold (Vth) to the vehicle speed (Vh) of the host vehicle; If both of the above conditions are met (step 530: Yes), the target inter-vehicle distance is reduced (step 535).

[0020] When both the second inter-vehicle distance condition (Da ≤ C2th) and the third relative speed condition (Vaf < Vh + Vth) are satisfied, the vehicle speed of the vehicle behind in the adjacent lane is slightly higher than the vehicle speed of the host vehicle. Therefore, even if the inter-vehicle distance between the host vehicle and the following target vehicle is relatively short (i.e., even when the second inter-vehicle distance condition is satisfied), there is a relatively high possibility that the vehicle behind in the adjacent lane will gently overtake the host vehicle and then cut in between the host vehicle and the following target vehicle. And when the vehicle behind in the adjacent lane actually cuts in between the host vehicle and the following target vehicle, the inter-vehicle distance between the host vehicle and the cutting-in vehicle behind in the adjacent lane becomes very short. Therefore, when both the second inter-vehicle distance condition (Da ≤ C2th) and the third relative speed condition (Vaf < Vh + Vth) are satisfied, the above aspect reduces the possibility that the vehicle behind in the adjacent lane will cut in between the host vehicle and the following target vehicle by shortening the target inter-vehicle distance. As a result, the frequency of the host vehicle being suddenly decelerated is reduced, so that the frequency with which the driver of the host vehicle feels anxiety can be reduced.

[0021] In the above aspect, the controller When it is determined that the specific situation has occurred (step 525: Yes), A third inter-vehicle distance condition that the distance (Da) from the host vehicle to the vehicle ahead in the adjacent lane is longer than a second threshold distance (C2th) that is longer than the first threshold distance, and A fourth relative speed condition that the vehicle speed (Vaf) of the vehicle behind in the adjacent lane is equal to or higher than a vehicle speed (Vh + Vth) obtained by adding a predetermined vehicle speed threshold (Vth) to the vehicle speed (Vh) of the host vehicle, When both are satisfied (step 545: Yes), it is configured to increase the target inter-vehicle distance (step 550).

[0022] When both the third inter-vehicle distance condition (Da>C2th) and the fourth relative speed condition (Vaf≧Vh+Vth) are met, there is a significant possibility that the following vehicle in the adjacent lane will quickly overtake the host vehicle and then cut in between the host vehicle and the target vehicle. Therefore, when both the third inter-vehicle distance condition (Da>C2th) and the fourth relative speed condition (Vaf≧Vh+Vth) are met, the above-described embodiment lengthens the target inter-vehicle distance. Therefore, even if the following vehicle in the adjacent lane actually cuts in between the host vehicle and the target vehicle, the inter-vehicle distance between the host vehicle and the cutting-in following vehicle in the adjacent lane will not be very short. As a result, the host vehicle is not suddenly decelerated, and the following vehicle in the adjacent lane can smoothly cut in between the host vehicle and the target vehicle, preventing the driver of the host vehicle from feeling uneasy.

[0023] The controller according to one of the above aspects includes: The vehicle speed (Vh) of the vehicle (HV) The vehicle speed (Vaf) of the adjacent lane rear vehicle (AF), A vehicle speed (Vap) of an adjacent lane preceding vehicle (AP) traveling in the adjacent lane immediately before the adjacent lane rear vehicle, and The distance (Da) from the host vehicle (HV) to the preceding vehicle (AP) in the adjacent lane, , and determines whether the specific situation occurs (step 525).

[0024] This allows for accurate determination of whether or not a specific situation has occurred.

[0025] In the above description, to facilitate understanding of the present invention, the names and / or symbols used in the embodiments described below are enclosed in parentheses for the components of the invention corresponding to those embodiments. However, the components of the present invention are not limited to the embodiments defined by the names and / or symbols. The present invention also covers a vehicle driving control method and a program therefor. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic diagram of a vehicle driving control device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the subject vehicle, a vehicle to be followed (a preceding vehicle in the subject lane), a following vehicle in an adjacent lane, and a preceding vehicle in an adjacent lane. [Figure 3] This is a routine executed by the CPU of the driving assistance ECU shown in FIG. [Figure 4] This is a routine executed by the CPU of the driving assistance ECU shown in FIG. [Figure 5] This is a routine executed by the CPU of the driving assistance ECU shown in FIG. [Figure 6] 1 is a diagram showing the positional relationships of a vehicle, a vehicle to be followed (a preceding vehicle in the vehicle's lane), a vehicle behind in an adjacent lane, and a vehicle ahead in an adjacent lane, as well as parameters relating to these vehicles. [Figure 7] This is a routine executed by the CPU of the driving assistance ECU shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0027] A vehicle driving control device according to an embodiment of the present invention (hereinafter referred to as "the control device") will be described below with reference to the drawings. First, main terms used in this specification and the drawings will be described.

[0028] Own vehicle: Own vehicle equipped with this control device (vehicle of interest) Other vehicles: Vehicles other than your own vehicle · Current lane: The lane in which your vehicle is traveling Adjacent lanes: lanes adjacent to your own lane - Leading vehicle in own lane: Another vehicle traveling immediately in front of the own vehicle and in the own lane, which the own vehicle should follow to maintain a predetermined target distance between the other vehicle. A leading vehicle in the own lane is sometimes called a "vehicle to be followed." - Leading vehicle in adjacent lane: Another vehicle traveling in an adjacent lane, ahead of the vehicle. - Rear vehicle in adjacent lane: Another vehicle traveling in the adjacent lane, and traveling immediately behind the preceding vehicle in the adjacent lane.

[0029] (composition) The control device DS shown in Fig. 1 is mounted on a host vehicle. The host vehicle may be any of a vehicle powered by an internal combustion engine, a vehicle powered by an electric motor (i.e., an electric vehicle), a hybrid vehicle, etc.

[0030] This control device DS is equipped with a driving assistance ECU 10, a powertrain ECU 30, and a brake ECU 40. These ECUs are connected to each other via a communication and sensor system CAN (Controller Area Network) to enable data exchange. ECU is an abbreviation for Electronic Control Unit, and is also called a controller or computer. The ECU is an electronic control circuit that has a microcomputer as its main component. The microcomputer includes a CPU (processor), ROM, RAM, and an interface. The CPU performs various functions, which will be described later, by executing instructions (routines) stored in the memory (ROM).

[0031] The control device DS includes a front radar device 21, a left front-side radar device 22L, a right front-side radar device 22R, a left rear-side radar device 23L, a right rear-side radar device 23R, and a front camera device 24. These devices are also capable of exchanging data with the driving assistance ECU 10 via the CAN. Furthermore, the driving assistance ECU 10 is connected to an ACC operation switch 25 and a vehicle speed sensor 26 and receives output signals from these.

[0032] The front radar device 21, the left front-side radar device 22L, the right front-side radar device 22R, the left rear-side radar device 23L, and the right rear-side radar device 23R will be simply referred to as "radar devices" when there is no need to distinguish between them.

[0033] The radar device is a well-known device that acquires information about targets present around the vehicle using millimeter-wave radio waves, and includes a radar transceiver unit and a processing unit (radar ECU). The radar transceiver unit transmits millimeter waves within a predetermined detection range every time a predetermined time elapses, and receives millimeter waves reflected by targets. The radar transceiver unit transmits information about the transmitted and received millimeter waves to the processing unit. The processing unit acquires radar target information based on the information from the radar transceiver unit, and transmits the radar target information to the driving assistance ECU 10. The radar target information includes the distance between the position where the radar transceiver unit is located and the target, the azimuth of the target relative to the radar transceiver unit, and the relative speed of the target with respect to the radar transceiver unit.

[0034] The front radar device 21 is disposed at the front end of the host vehicle and in the center in the vehicle width direction. The front radar device 21 acquires radar target information about targets present in front of the host vehicle and transmits this radar target information to the driving assistance ECU 10.

[0035] The left front-side radar device 22L is disposed at the front end of the vehicle and at the left end in the vehicle width direction. The left front-side radar device 22L acquires radar target information about targets present on the left front side of the vehicle and transmits this radar target information to the driving assistance ECU 10.

[0036] The right front-side radar device 22R is disposed at the front end of the vehicle and at the right end in the vehicle width direction. The right front-side radar device 22R acquires radar target information about targets present on the right front side of the vehicle and transmits this radar target information to the driving assistance ECU 10.

[0037] The left rear-side radar device 23L is disposed at the rear end of the vehicle and at the left end in the vehicle width direction. The left rear-side radar device 23L acquires radar target information about targets present on the left rear side of the vehicle and transmits this radar target information to the driving assistance ECU 10.

[0038] The right rear-side radar device 23R is disposed at the rear end of the vehicle and at the right end in the vehicle width direction. The right rear-side radar device 23R acquires radar target information about targets present on the right rear side of the vehicle and transmits this radar target information to the driving assistance ECU 10.

[0039] The driving assistance ECU 10 integrates the radar target information transmitted from these radar devices to generate radar integrated target information about targets present around the host vehicle. Note that, hereinafter, the target information is expressed using an XY coordinate system. The X coordinate axis of this XY coordinate system is an axis that extends in the longitudinal direction of the host vehicle and passes through the center of the host vehicle in the vehicle width direction. The Y coordinate axis of the XY coordinate system is an axis that is perpendicular to the X coordinate axis. The origin of the XY coordinate system is the center position of the front end of the host vehicle in the vehicle width direction. The X coordinate is a positive value in the front direction of the vehicle and a negative value in the rear direction of the vehicle. The Y coordinate is a positive value in the left direction of the vehicle and a negative value in the right direction of the vehicle.

[0040] The forward camera device 24 includes a "camera and image ECU" (not shown). The camera captures an image of the scene ahead of the vehicle at predetermined intervals to acquire image data. Based on the image data from the camera, the image ECU recognizes (detects) the "left and right boundary lines" of the vehicle's own lane, the "left and right boundary lines" of the adjacent lane on the left side of the vehicle's own lane, and the "left and right boundary lines" of the adjacent lane on the right side of the vehicle's own lane. Note that lane boundary lines are generally lane markings, such as white and yellow lines. The left boundary line of the vehicle's own lane is the right boundary line of the adjacent lane on the left. The right boundary line of the vehicle's own lane is the left boundary line of the adjacent lane on the right. Furthermore, the image ECU generates camera target information based on the image data from the camera. The camera target information includes the "position (longitudinal and lateral positions) and type" of targets present ahead of the vehicle. The driving assistance ECU 10 integrates the radar integrated target information and the camera target information to generate fusion target information, which is final target information about targets present around the host vehicle.

[0041] The ACC operation switch 25 is a switch operated by the driver of the host vehicle. ACC stands for adaptive cruise control. When the driver performs a predetermined operation on the ACC operation switch 25, an ACC start request and an ACC stop request are generated in response to that operation. Furthermore, another predetermined operation on the ACC operation switch 25 changes the set inter-vehicle time Tset, which is set as the target inter-vehicle time Ttgt.

[0042] The vehicle speed sensor 26 detects the speed of the host vehicle (host vehicle speed) Vh, and outputs a signal indicative of the host vehicle speed Vh.

[0043] The powertrain ECU 30 is connected to a powertrain sensor 31 and a powertrain actuator 32. The powertrain ECU 30 receives detection signals from the powertrain sensor 31. The powertrain sensor 31 includes an accelerator pedal operation amount sensor and, if the drive source is an internal combustion engine, an engine rotation speed sensor. The powertrain ECU 30 controls a drive device including a power source of the host vehicle (not shown) by driving the powertrain actuator 32, thereby adjusting the drive force of the host vehicle.

[0044] The brake ECU 40 is connected to a brake sensor 41 and a brake actuator 42. The brake ECU 40 receives a detection signal from the brake sensor 41. The brake sensor 41 includes a brake pedal operation amount sensor and a wheel speed sensor that detects the wheel speed of each wheel. The brake ECU 40 controls a braking device of the host vehicle (not shown) by driving the brake actuator 42, thereby adjusting the braking force applied to the host vehicle.

[0045] (Overview of operation) As shown in Figure 2, the control device DS performs follow-up distance control to cause the host vehicle HV to follow a preceding vehicle (vehicle to be followed) PV in the host lane HL so that the inter-vehicle distance Dh between the host vehicle HV and the preceding vehicle PV in the host lane HL is maintained at a predetermined target inter-vehicle distance Dtgt. The predetermined target inter-vehicle distance Dtgt is usually a set inter-vehicle distance Dset set by the driver of the host vehicle HV. The set inter-vehicle distance Dset is equal to the product (Vh·Tset) of the host vehicle speed Vh and the set inter-vehicle time Tset set by the driver of the host vehicle HV.

[0046] During the execution of adaptive vehicle-following distance control, a situation may occur in which a preceding vehicle AP in an adjacent lane traveling at a speed slower than the host vehicle speed Vh is traveling in the adjacent lane AL, and a following vehicle AF in an adjacent lane traveling at a speed faster than the host vehicle speed Vh is traveling in the adjacent lane AL from behind the preceding vehicle AP in the adjacent lane so as to approach the preceding vehicle AP in the adjacent lane. This situation is a specific situation in which the following vehicle AF in the adjacent lane may cut in between the host vehicle HV and the preceding vehicle PV in the same lane, as shown by the arrow CI in FIG. 2.

[0047] When this rear vehicle AF in the adjacent lane cuts in, the cutting-in rear vehicle AF becomes the leading vehicle PV in the host vehicle HV's lane. As a result, the inter-vehicle distance between the host vehicle HV and the leading vehicle PV becomes much shorter than before the cutting-in, and the host vehicle HV is suddenly decelerated by adaptive inter-vehicle distance control. This situation occurs frequently when the inter-vehicle distance Dh before the cutting-in occurs is relatively long. As a result, the host vehicle HV is frequently suddenly decelerated due to frequent cutting-ins, which is likely to cause the driver of the host vehicle HV to feel uncomfortable or uneasy.

[0048] Therefore, when a specific situation occurs and a condition for increasing the target inter-vehicle distance, which will be described later, is met, the control device DS lengthens (increases) the target inter-vehicle distance Dtgt before the rear vehicle in the adjacent lane cuts in. This lengthens the inter-vehicle distance Dh between the leading vehicle PV in the same lane and the host vehicle HV, allowing the rear vehicle in the adjacent lane to cut in smoothly, and also reducing the possibility that the host vehicle HV will be suddenly decelerated by the adaptive inter-vehicle distance control, because the inter-vehicle distance between the host vehicle HV and the rear vehicle AF in the adjacent lane that has cut in becomes relatively long. As a result, it is possible to reduce the possibility that the driver will feel uncomfortable or uneasy.

[0049] In response to this, when a specific situation occurs and a condition for reducing the target inter-vehicle distance, which will be described later, is met, the control device DS shortens (reduces) the target inter-vehicle distance Dtgt before a rear vehicle in an adjacent lane cuts in. This shortens the inter-vehicle distance Dh between the leading vehicle PV in the own lane and the own vehicle HV, reducing the possibility that a rear vehicle in an adjacent lane will cut in. This reduces the frequency with which the own vehicle HV is suddenly decelerated by the following inter-vehicle distance control. As a result, the frequency with which the driver feels discomfort or anxiety can be reduced.

[0050] (Specific operation) The CPU of the driving assistance ECU 10 (hereinafter, when written as "CPU", unless otherwise specified, refers to the CPU of the driving assistance ECU 10) is configured to execute the routines shown in the flowcharts of Figures 3 to 5 and Figure 7 every time a predetermined time has elapsed.

[0051] 1. ACC (Adaptive Car-to-Car Distance Control) start / end determination 3, the CPU starts processing from step 300 and determines whether the value of the ACC execution flag XACC is "0" in step 310. The value of the ACC execution flag XACC is set to "1" when the ACC start condition is met (see step 340 described later), and is set to "0" when the ACC end condition is met (see step 360 described later).

[0052] The values ​​of the ACC execution flag XACC and the flags described below are set to "0" by an initialization routine (not shown) executed by the CPU when the start switch (e.g., ignition key switch and ready switch) (not shown) of the host vehicle HV is changed from the OFF position to the ON position.

[0053] If the value of the ACC execution flag is "0", the CPU determines "Yes" in step 310 and proceeds to step 320 to determine whether the ACC start condition is met. The ACC start condition is met, for example, when a predetermined operation is performed on the ACC operation switch 25 to instruct the start of follow-up distance control while follow-up distance control is not being executed (i.e., when an ACC start request is generated).

[0054] If the ACC start condition is not satisfied, the CPU determines "No" in step 320, proceeds directly to step 395, and temporarily ends this routine. On the other hand, if the ACC start condition is satisfied, the CPU determines "Yes" in step 320, sequentially performs the processes of step 330 and step 340 described below, proceeds to step 395, and temporarily ends this routine.

[0055] Step 330: The CPU sets the target inter-vehicle time Ttgt to the set inter-vehicle time Tset selected by the driver. The driver can set the set inter-vehicle time Tset to one of a short time Tshort, a medium time Tmedium, and a long time Tlong by operating the ACC operation switch 25. The relationship between the times Tshort, Tmedium, and Tlong is expressed by the following equation (1). 0 <Tshort<Tmedium<Tlong …(1)

[0056] Step 340: The CPU sets the value of the ACC execution flag to 1. As a result, the following vehicle distance control is executed by the routine shown in FIG. 4, which will be described later.

[0057] When the CPU proceeds to step 310, if the value of the ACC execution flag is not "0" (i.e., "1"), the CPU determines "No" in step 310 and proceeds to step 350. In step 350, the CPU determines whether or not the ACC termination condition is met. The ACC termination condition is met, for example, when a predetermined operation is performed on the ACC operation switch 25 to instruct the termination of the follow-up distance control while the follow-up distance control is being executed (i.e., when an ACC termination request is generated).

[0058] If the ACC termination condition is not met, the CPU determines "No" in step 350, proceeds directly to step 395, and temporarily ends this routine. On the other hand, if the ACC termination condition is met, the CPU determines "Yes" in step 350, sequentially performs the processes of steps 360 to 390 described below, proceeds to step 395, and temporarily ends this routine.

[0059] Step 360: The CPU sets the value of the ACC execution flag XACC to “0”. Step 370: The CPU sets the value of the following distance control execution flag XFU to "0." Step 380: The CPU sets the value of the following distance reduction flag XS to "0". Step 390: The CPU sets the value of the following distance increase flag XL to "0".

[0060] 2. ACC (Adaptive Car-to-Car Distance Control) 4, and determines whether the value of the ACC execution flag XACC is "1" in step 410. If the value of the ACC execution flag XACC is not "1" (i.e., if the value of the ACC execution flag XACC is "0"), the CPU determines "No" in step 410, proceeds directly to step 495, and temporarily ends this routine.

[0061] On the other hand, if the value of the ACC execution flag XACC is "1", the CPU determines "Yes" in step 410 and proceeds to step 420. In step 420, the CPU determines whether or not there is a preceding vehicle to be followed in the own lane (i.e., a preceding vehicle in the own lane that is the vehicle to be followed) in the own lane. For example, when there is another vehicle traveling in the own lane and just before the own vehicle, and the inter-vehicle distance between the other vehicle and the own vehicle is within a predetermined threshold inter-vehicle distance, the CPU determines that the other vehicle is a preceding vehicle in the own lane.

[0062] If there is a preceding vehicle in the current lane (vehicle to be followed), the CPU judges "Yes" in step 420, sequentially performs the processing of "steps 430 to 450" described below, and then proceeds to step 495 to temporarily end this routine.

[0063] Step 430: The CPU obtains the target inter-vehicle distance Dtgt by substituting the target inter-vehicle time Ttgt and the host vehicle speed Vh into the following equation (2). That is, the target inter-vehicle distance Dtgt is the product of the host vehicle speed Vh and the target inter-vehicle time Ttgt. As is clear from equation (2), the target inter-vehicle distance Dtgt becomes longer as the target inter-vehicle time Ttgt becomes longer, and becomes shorter as the target inter-vehicle time Ttgt becomes shorter. Dtgt = Vh Ttgt …(2)

[0064] Step 440: The CPU executes the following inter-vehicle distance control. More specifically, the CPU calculates the following target acceleration Gtgt according to the following equations (3) and (4). Then, the CPU sends instructions to the powertrain ECU 30 and the brake ECU 40 to control the acceleration of the host vehicle so that the actual acceleration of the host vehicle (the amount of change in the host vehicle speed Vh per unit time) coincides with the following inter-vehicle distance Gtgt. Note that Dh in equation (3) is the actual inter-vehicle distance between the host vehicle HV and the preceding vehicle PV in the host lane (see FIG. 6). Vrelative in equation (4) is the relative speed of the preceding vehicle PV in the host lane with respect to the host vehicle HV, and takes a positive value when the preceding vehicle PV in the host lane moves away from the host vehicle HV. K0, K1, and K2 are predetermined positive gains (coefficients). Inter-vehicle distance deviation ΔD = actual inter-vehicle distance Dh - target inter-vehicle distance Dtgt ... (3) Target acceleration for tracking Gtgt = K0 (K1 ΔD + K2 Vrelative) … (4)

[0065] Step 450: The CPU sets the value of the inter-vehicle distance control execution flag XFU to “1”.

[0066] On the other hand, when the CPU proceeds to step 420, if there is no preceding vehicle (vehicle to be followed) in the own lane, the CPU determines "No" in step 420 and proceeds to step 460. In step 460, the CPU executes well-known constant speed cruise control. That is, the CPU stores the own vehicle speed when the ACC start request is generated as the target vehicle speed, and controls the acceleration of the own vehicle so that the actual own vehicle speed Vh matches the target vehicle speed. The driver can change the target vehicle speed by performing a predetermined acceleration or deceleration operation on the ACC operation switch 25.

[0067] Next, the CPU proceeds to step 470 and sets the value of the following distance control in progress flag XFU to "0". After that, the CPU proceeds to step 495 and temporarily ends this routine. In this way, the value of the following distance control in progress flag XFU is set to "1" when the following distance control for the preceding vehicle in the same lane is being executed.

[0068] 3. Changing the target inter-vehicle time (target distance) At a predetermined timing, the CPU starts processing from step 500 in Fig. 5, and determines whether the value of the inter-vehicle distance control execution flag XFU is "1" in step 505. That is, the CPU determines whether the follow-up inter-vehicle distance control is currently being executed in step 505. If the value of the inter-vehicle distance control execution flag XFU is not "1," the CPU determines "No" in step 505, proceeds directly to step 595, and temporarily ends this routine.

[0069] If the value of the inter-vehicle distance control in progress flag XFU is "1", the CPU determines "Yes" in step 505 and proceeds to step 510. In step 510, the CPU determines whether the value of the inter-vehicle distance increase flag XL is "0". That is, in step 510, the CPU determines whether the current state is a state in which "adaptive inter-vehicle distance control using an increased (lengthened) target inter-vehicle distance" is not being executed. If the value of the inter-vehicle distance increase flag XL is not "0", the CPU determines "No" in step 510 and proceeds directly to step 595.

[0070] If the value of the following distance increase flag XL is "0", the CPU determines "Yes" in step 510 and proceeds to step 515. The CPU determines whether the value of the following distance reduction flag XS is "0" in step 515. That is, the CPU determines whether the current state is a state in which "adaptive inter-vehicle distance control using a reduced (shortened) target inter-vehicle distance" is not being executed. If the value of the inter-vehicle distance reduction flag XS is not "0", the CPU determines "No" in step 515 and proceeds directly to step 595.

[0071] If the value of the inter-vehicle distance reduction flag XS is "0," the CPU determines "Yes" in step 515 and proceeds to step 520. In step 520, the CPU determines whether the absolute value (magnitude) of the difference between the actual inter-vehicle distance Dh between the host vehicle HV and the preceding vehicle PV in the same lane and the target inter-vehicle distance Dtgt is equal to or less than the threshold distance Dth. In this case, since the target inter-vehicle time Ttgt is set to the set inter-vehicle time Tset selected by the driver, the target inter-vehicle distance Dtgt is "the set inter-vehicle distance Dset equal to the product of the host vehicle speed Vh and the set inter-vehicle time Tset (= Vh·Tset)." Therefore, in step 520, the CPU determines whether the actual inter-vehicle distance Dh is substantially equal to the set inter-vehicle distance Dset.

[0072] If the absolute value (magnitude) of the difference between the actual inter-vehicle distance Dh and the target inter-vehicle distance Dtgt is not equal to or less than the threshold distance Dth, the CPU determines "No" in step 520 and proceeds to step 595. On the other hand, if the absolute value (magnitude) of the difference between the actual inter-vehicle distance Dh and the target inter-vehicle distance Dtgt is equal to or less than the threshold distance Dth, the CPU determines "Yes" in step 520 and proceeds to step 525.

[0073] It is possible to omit step 520. In this case, when the CPU determines "Yes" in step 515, it proceeds to step 525.

[0074] In step 525, the CPU determines whether the above-mentioned specific situation (i.e., a situation in which the rear vehicle AF in the adjacent lane may cut in between the host vehicle HV and the leading vehicle PV in the host lane) has occurred. The specific situation is met when all of the following conditions 1T to 5T are met. As shown in FIG. 6, the values ​​used for these conditions are as follows:

[0075] Vh: own vehicle speed Vap: Vehicle speed of the preceding vehicle AP in the adjacent lane Vaf: Speed ​​of the rear vehicle AF in the adjacent lane Da: Distance between the leading edge of the host vehicle HV and the trailing edge of the preceding vehicle AP in the adjacent lane (i.e., distance from the host vehicle HV to the preceding vehicle AP in the adjacent lane)

[0076] <Conditions for specific situations to occur> (Condition 1T) A preceding vehicle AP is present in the adjacent lane, and the rear end position of the preceding vehicle AP in the adjacent lane is ahead of the front end position of the host vehicle HV. In other words, the distance Da between the leading edge of the host vehicle HV and the rear end position of the preceding vehicle AP in the adjacent lane (i.e., the distance from the host vehicle HV to the preceding vehicle in the adjacent lane) is equal to or greater than 0 (Da≧0).

[0077] (Condition 2T) A rear vehicle AF is present in the adjacent lane, and the front end position of the rear vehicle AF in the adjacent lane is behind the rear end position of the host vehicle HV or is the same as the rear end position of the host vehicle HV.

[0078] (Condition 3T) When the front end position of the rear vehicle AF in the adjacent lane reaches a position that satisfies a predetermined relationship with respect to the host vehicle HV, the vehicle speed Vaf of the rear vehicle AF in the adjacent lane is higher than the host vehicle speed Vh (Vaf>Vh). For convenience, the condition that the vehicle speed Vaf of the rear vehicle AF in the adjacent lane is higher than the host vehicle speed Vh (Vaf>Vh) is referred to as the "first relative speed condition."

[0079] (Condition 4T) When the front end position of the rear vehicle AF in the adjacent lane reaches a position that satisfies a predetermined relationship with respect to the host vehicle HV, the vehicle speed Vap of the preceding vehicle AP in the adjacent lane is equal to or less than the host vehicle speed Vh (Vap≦Vh). For convenience, the condition that the vehicle speed Vap of the preceding vehicle AP in the adjacent lane is equal to or less than the host vehicle speed Vh (Vap≦Vh) is referred to as the "second relative speed condition."

[0080] (Condition 5T) When the front end position of the rear vehicle AF in the adjacent lane reaches a position that satisfies a predetermined relationship with respect to the host vehicle HV, the distance Da between the leading edge position of the host vehicle HV and the rear end position of the preceding vehicle AP in the adjacent lane is equal to or greater than a first threshold distance C1th (C1th≦Da). The condition that the distance Da is equal to or greater than the first threshold distance C1th (C1th≦Da) is referred to as the "first inter-vehicle distance condition" for convenience. For example, the first threshold distance C1th is the total length of a light vehicle (e.g., 3.3 m) under the light vehicle standard.

[0081] In some of the above conditions and some of the conditions described below, the phrase "when the front end position of the rear vehicle AF in the adjacent lane reaches a position that satisfies a predetermined relationship with respect to the host vehicle HV" means when the front end position of the rear vehicle AF in the adjacent lane reaches a specific position between a specific rear position that is a first predetermined distance rearward from the rear end position of the host vehicle HV and a specific forward position that is a second predetermined distance forward from the front end position of the host vehicle HV. The specific position is, for example, the rear end position of the host vehicle HV. In this case, "when the front end position of the rear vehicle AF in the adjacent lane reaches a position that satisfies a predetermined relationship with respect to the host vehicle HV" is synonymous with "when the front end position of the rear vehicle AF in the adjacent lane coincides with the front end position of the host vehicle HV."

[0082] As described above, the control device DS determines whether or not the specific situation has occurred based on the vehicle speed Vh of the host vehicle, the vehicle speed Vaf of the vehicle behind in the adjacent lane, the vehicle speed Vap of the vehicle ahead in the adjacent lane, and the distance Da from the host vehicle to the vehicle ahead in the adjacent lane. [[ID=Z]]

[0083] When the specific situation has not occurred, the CPU determines "No" in step 525 and directly proceeds to step 595 to temporarily end this routine. On the other hand, when the specific situation has occurred, the CPU determines "Yes" in step 525 and proceeds to step 530.

[0084] In step 530, the CPU determines whether or not the condition for reducing the target inter-vehicle distance is satisfied. The condition for reducing the target inter-vehicle distance is satisfied when both of the following condition 1S and condition 2S are satisfied.

[0085] <Condition for reducing the target inter-vehicle distance> (Condition 1S) When the front-end position of the vehicle AF behind in the adjacent lane reaches a position that satisfies a predetermined relationship with respect to the host vehicle HV, the vehicle speed Vaf of the vehicle AF behind in the adjacent lane is lower than the value (Vh + Vth) obtained by adding the vehicle speed threshold Vth to the vehicle speed Vh of the host vehicle (Vaf < Vh + Vth). The condition that the vehicle speed Vaf of the vehicle AF behind in the adjacent lane is lower than the value (Vh + Vth) obtained by adding the vehicle speed threshold Vth to the vehicle speed Vh of the host vehicle (Vaf < Vh + Vth) is, for convenience, referred to as the "third relative speed condition".

[0086] When both condition 3T and condition 1S are satisfied (Vh < Vaf < Vh + Vth), it can be said that the vehicle speed Vaf is higher than the vehicle speed Vh of the host vehicle but not extremely higher than the vehicle speed Vh of the host vehicle. <zH

[0087] (Condition 2S) When the front-end position of the vehicle AF behind in the adjacent lane reaches a position that satisfies a predetermined relationship with respect to the host vehicle HV, the distance Da between the front-end position of the host vehicle HV and the rear-end position of the vehicle AP ahead in the adjacent lane is not more than the second threshold distance C2th that is longer than the first threshold distance C1th (Da ≤ C2th). The condition that the distance Da is not more than the second threshold distance C2th (Da ≤ C2th) is, for convenience, referred to as the "second inter-vehicle distance condition".

[0088] When both condition 5T and condition 2S are met (C1th≦Da≦C2th), the distance Da can be said to be a relatively short distance that allows for interruption. For example, the second threshold distance C2th is twice the overall length of a passenger car (e.g., 9.4 m) according to passenger car standards.

[0089] If the condition for reducing the target inter-vehicle distance is met, the CPU determines "Yes" in step 530 of FIG. 5, sequentially performs the processing of "step 535 and step 540" described below, and then proceeds to step 595 to temporarily end this routine.

[0090] Step 535: The CPU sets the target inter-vehicle time Ttgt to the time (Tshort - dta) obtained by subtracting a positive constant value dta from the short time Tshort. As a result, the target inter-vehicle distance Dtgt, which is the product of the host vehicle speed Vh and the target inter-vehicle time Ttgt, is shortened (see step 430 in FIG. 4). Therefore, the inter-vehicle distance between the host vehicle HV and the preceding vehicle PV in the same lane is shortened by the adaptive inter-vehicle distance control. Note that the constant value dta may be "0." In this case, the target inter-vehicle distance Dtgt is shortened only when the set inter-vehicle time Tset is set to either the medium time Tmedium or the long time Tlong. That is, in this case, the target inter-vehicle distance Dtgt is set to the distance corresponding to the shortest target inter-vehicle time (Tshort) that the control device DS allows the driver. Step 540: The CPU sets the value of the following distance reduction flag XS to “1”.

[0091] On the other hand, if the condition for reducing the target inter-vehicle distance is not met when the CPU proceeds to step 530, the CPU determines "No" in step 530 and proceeds to step 545. The CPU determines whether the condition for increasing the target inter-vehicle distance is met in step 545. The condition for increasing the target inter-vehicle distance is met when both Condition 1L and Condition 2L described below are met.

[0092] <Conditions for increasing target inter-vehicle distance> (Condition 1L) When the front end position of the following vehicle AF in the adjacent lane reaches a position that satisfies a predetermined relationship with respect to the host vehicle HV, the vehicle speed Vaf of the following vehicle AF in the adjacent lane is equal to or greater than the value (Vh+Vth) obtained by adding the host vehicle speed Vh to the vehicle speed threshold Vth (Vaf≧Vh+Vth). In other words, the vehicle speed Vaf is significantly higher than the host vehicle speed Vh. For convenience, the condition that the vehicle speed Vaf of the following vehicle AF in the adjacent lane is equal to or greater than the value (Vh+Vth) obtained by adding the host vehicle speed Vh to the vehicle speed threshold Vth (Vaf≧Vh+Vth) is referred to as the "fourth relative speed condition."

[0093] (Condition 2L) When the front end of the rear vehicle AF in the adjacent lane reaches a position that satisfies a predetermined relationship with respect to the host vehicle HV, the distance Da between the leading edge of the host vehicle HV and the rear end of the preceding vehicle AP in the adjacent lane is longer than the second threshold distance C2th (Da>C2th). For convenience, the condition that the distance Da is longer than the second threshold distance C2th (Da>C2th) is referred to as the "third inter-vehicle distance condition."

[0094] When the condition 2L is satisfied (Da>C2th), it can be said that the distance Da is long enough to induce a rear vehicle in an adjacent lane to cut in.

[0095] If the condition for increasing the target inter-vehicle distance is met, the CPU determines "Yes" in step 545, sequentially performs the processing of "step 550 and step 555" described below, and then proceeds to step 595 to temporarily end this routine.

[0096] Step 550: The CPU sets the target inter-vehicle time Ttgt to a time (Tlong + dtb) obtained by adding a positive constant value dtb to the long time Tlong. As a result, the target inter-vehicle distance Dtgt, which is the product of the host vehicle speed Vh and the target inter-vehicle time Ttgt, is lengthened (expanded) (see step 430 in FIG. 4). Therefore, the following inter-vehicle distance control lengthens the inter-vehicle distance between the host vehicle HV and the preceding vehicle PV in the same lane. Note that the constant value dtb may be "0." In this case, the target inter-vehicle distance Dtgt is lengthened only when the set inter-vehicle time Tset is set to either a short time Tshort or a medium time Tmedium. That is, in this case, the target inter-vehicle distance Dtgt is set to a distance corresponding to the longest target inter-vehicle time (Tlong) that the control device DS allows the driver. Step 555: The CPU sets the value of the following distance increase flag XL to “1”.

[0097] When the CPU proceeds to step 545, if the condition for increasing the target inter-vehicle distance is not met, the CPU determines "No" in step 545 and proceeds to step 595.

[0098] 4. End of target inter-vehicle time change 7, and determines whether the value of the following distance increase flag XL is "1" in step 710. If the value of the following distance increase flag XL is "1," the CPU determines "Yes" in step 710 and proceeds to step 730, which will be described later.

[0099] On the other hand, if the value of the following distance increase flag XL is not "1", the CPU determines "No" in step 710 and proceeds to step 720. The CPU determines whether the value of the following distance reduction flag XS is "1" in step 720. If the value of the following distance reduction flag XS is "1", the CPU determines "Yes" in step 710 and proceeds to step 730, which will be described later. If the value of the following distance reduction flag XS is not "1", the CPU determines "No" in step 710, proceeds directly to step 795, and temporarily ends this routine.

[0100] In step 730, the CPU determines whether or not the conditions for ending the change (expansion / reduction) of the target inter-vehicle distance are met. The conditions for ending the change of the target inter-vehicle distance are met when at least one of the following conditions E1 to E4 is met.

[0101] (Condition E1) The preceding vehicle AP in the adjacent lane no longer exists. This condition E1 is met, for example, when the preceding vehicle AP in the adjacent lane changes lanes or the host vehicle HV overtakes the preceding vehicle AP in the adjacent lane.

[0102] (Condition E2) The following vehicle AF in the adjacent lane no longer exists. This condition E2 is met, for example, when the following vehicle AF in the adjacent lane changes lanes, or when the following vehicle AF in the adjacent lane cuts in front of the host vehicle HV and becomes the new vehicle to be followed (the leading vehicle in the host vehicle's lane).

[0103] (Condition E3) The vehicle speed Vap of the preceding vehicle AP in the adjacent lane becomes higher than the vehicle speed Vh (Vap>Vh). (Condition E4) The vehicle speed Vaf of the rear vehicle AF in the adjacent lane is lower than the vehicle speed Vh (Vaf <Vh)。

[0104] If the condition for ending the change of the target inter-vehicle distance is not met, the CPU determines "No" in step 730, proceeds directly to step 795, and ends this routine for the time being.

[0105] On the other hand, if the condition for ending the change of the target inter-vehicle distance is met, the CPU judges "Yes" in step 730, sequentially performs the processing of "steps 740 to 760" described below, and then proceeds to step 795 to temporarily end this routine.

[0106] Step 740: The CPU sets the target inter-vehicle time Ttgt to the set inter-vehicle time Tset, thereby restoring the target inter-vehicle distance Dtgt to the set inter-vehicle distance Dset.

[0107] Step 750: The CPU sets the value of the following distance reduction flag XS to "0". Step 760: The CPU sets the value of the following distance increase flag XL to “0”.

[0108] As described above, when a specific situation occurs in which the rear vehicle AF in the adjacent lane may cut in between the host vehicle HV and the leading vehicle PV in the same lane while adaptive vehicle distance control is being performed, the control device DS shortens or lengthens the inter-vehicle distance between the host vehicle HV and the leading vehicle PV in the same lane. As a result, the rear vehicle AF in the adjacent lane can be prevented from cutting in unreasonably or the rear vehicle AF in the adjacent lane can be allowed to cut in smoothly. Even if the vehicle actually cuts in, the inter-vehicle distance between the host vehicle and the vehicle that cut in will not become extremely short. Therefore, the host vehicle will not be suddenly decelerated by adaptive vehicle distance control, which reduces the possibility that the driver of the host vehicle will feel uncomfortable and / or anxious.

[0109] The present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention. For example, the present invention can be applied to an autonomous vehicle that is in an autonomous driving state, or an autonomous vehicle that has transitioned from an autonomous driving mode to a driver-driven mode.

[0110] Although the present control device DS sets the precondition for the occurrence of the specific situation as the presence of both the preceding vehicle AP in the adjacent lane and the following vehicle AF in the adjacent lane, the presence of at least the following vehicle AF in the adjacent lane may also be set as the precondition for the occurrence of the specific situation. In other words, the presence of the preceding vehicle AP in the adjacent lane does not have to be set as the precondition for the occurrence of the specific situation.

[0111] In this case, the control device DS may determine that a specific situation has occurred when at least a first relative speed condition (Vaf>Vh) is met, which states that the vehicle speed (Vaf) of the rear vehicle in the adjacent lane is higher than the vehicle speed (Vh) of the host vehicle.

[0112] Furthermore, as a precondition for the occurrence of the specific situation, a condition may be added in which the turn signal on the cutting-in side of the rear vehicle AF in the adjacent lane (the turn signal on the side from the adjacent lane toward the own lane) is flashing.

[0113] Furthermore, the control device DS may determine that a specific situation has occurred when, in addition to the first relative speed condition, at least a second relative speed condition (Vap≦Vh) is satisfied, which condition states that a preceding vehicle (AP) in an adjacent lane is present and that the vehicle speed (Vap) of the preceding vehicle (AP) in the adjacent lane is equal to or less than the vehicle speed (Vh) of the host vehicle. Note that the second relative speed condition may be satisfied when the absolute value (magnitude) of the difference between the vehicle speed (Vap) of the preceding vehicle (AP) in the adjacent lane and the vehicle speed (Vh) of the host vehicle is within a predetermined vehicle speed difference. In other words, the control device DS may determine that a specific situation has occurred even if the vehicle speed (Vap) of the preceding vehicle (AP) in the adjacent lane is equal to or less than a value slightly higher than the vehicle speed (Vh) of the host vehicle (equal to or less than the value obtained by adding a positive predetermined value α to the host vehicle speed Vh) (Vap≦Vh+α, α>0).

[0114] Furthermore, the control device DS may determine that a specific situation has occurred when, in addition to the first relative speed condition and the second relative speed condition, a first inter-vehicle distance condition (Da≧C1th) is met, which states that the distance (Da) from the host vehicle (HV) to the preceding vehicle (AP) in the adjacent lane is equal to or greater than a first threshold distance (C1th).

[0115] Furthermore, the control device DS determines that the condition for reducing the target inter-vehicle distance is met when both a second inter-vehicle distance condition, that is, the distance (Da) from the vehicle to the preceding vehicle in the adjacent lane is equal to or less than a second threshold distance (C2th), and a third relative speed condition, that is, the vehicle speed (Vaf) of the following vehicle in the adjacent lane is lower than a predetermined vehicle speed (Vh+Vth), are met. However, the control device DS may also determine that the condition for reducing the target inter-vehicle distance is met when at least the second inter-vehicle distance condition (Da≦C2th) is met.

[0116] Similarly, the control device DS determines that the condition for increasing the target inter-vehicle distance is met when both a third inter-vehicle distance condition that the distance (Da) from the host vehicle to the preceding vehicle in the adjacent lane is longer than the second threshold distance (C2th) and a fourth relative speed condition that the vehicle speed (Vaf) of the following vehicle in the adjacent lane is equal to or greater than a predetermined vehicle speed (Vh+Vth) are met. However, the control device DS may also determine that the condition for increasing the target inter-vehicle distance is met when at least the third inter-vehicle distance condition (Da>C2th) is met.

[0117] Furthermore, the control device DS may determine that the condition for increasing the target inter-vehicle distance is met if the condition for reducing the target inter-vehicle distance is not met when the specific situation described above occurs. Similarly, the control device DS may determine that the condition for reducing the target inter-vehicle distance is met if the condition for increasing the target inter-vehicle distance is not met when the specific situation described above occurs.

[0118] The control device DS sets the product of the target inter-vehicle time Ttgt and the vehicle speed Vh as the target inter-vehicle distance Dtgt, and changes the target inter-vehicle distance Dtgt by changing the target inter-vehicle time Ttgt. However, the control device DS may directly set or change the target inter-vehicle distance Dtgt without using the target inter-vehicle time Ttgt.

[0119] Furthermore, the control device DS may be configured to display a message indicating that the target inter-vehicle distance will be shortened or to issue a voice message indicating that the target inter-vehicle distance will be shortened when the target inter-vehicle distance shortening condition is met. Similarly, the control device DS may be configured to display a message indicating that the target inter-vehicle distance will be lengthened or to issue a voice message indicating that the target inter-vehicle distance will be lengthened when the target inter-vehicle distance lengthening condition is met. Alternatively, the control device DS may be configured to display a message indicating that the target inter-vehicle distance will be changed or to issue a voice message indicating that the target inter-vehicle distance will be changed when the target inter-vehicle distance shortening condition or lengthening condition is met. [Explanation of symbols]

[0120] 10...driving assistance ECU, 21...front radar device, 22L...left front side radar device, 22R...right front side radar device, 23L...left rear side radar device, 23R...right rear side radar device, 24...front camera device, 25...ACC operation switch, 26...vehicle speed sensor, 30...power train ECU.

Claims

1. A vehicle travel control device including a controller capable of performing follow-up inter-vehicle distance control for causing a host vehicle to travel so that an inter-vehicle distance between the host vehicle and a target vehicle traveling immediately ahead of the host vehicle is maintained at a predetermined target inter-vehicle distance, The controller During execution of the following inter-vehicle distance control, if a specific situation occurs in which a rear vehicle in an adjacent lane that is adjacent to the own vehicle's own lane and that is traveling behind the own vehicle and there is a possibility that the rear vehicle in the adjacent lane will cut in between the own vehicle and the vehicle to be followed, the target inter-vehicle distance is changed. Driving control device.

2. The vehicle driving control device according to claim 1, The controller The vehicle speed controller is configured to determine that the specific situation has occurred when a first relative speed condition is satisfied, where the vehicle speed of the rear vehicle in the adjacent lane is higher than the vehicle speed of the host vehicle. Driving control device.

3. 3. The vehicle driving control device according to claim 2, The controller The vehicle control device is configured to determine that the specific situation has occurred when, in addition to the first relative speed condition, a second relative speed condition is satisfied in which a preceding vehicle in the adjacent lane is present in the adjacent lane and traveling immediately before the rear vehicle in the adjacent lane, and the vehicle speed of the preceding vehicle in the adjacent lane is equal to or lower than the vehicle speed of the host vehicle. Driving control device.

4. 4. The vehicle driving control device according to claim 3, The controller the control unit is configured to determine that the specific situation has occurred when, in addition to the first relative speed condition and the second relative speed condition, a first inter-vehicle distance condition that a distance from the host vehicle to the preceding vehicle in the adjacent lane is equal to or greater than a first threshold distance is satisfied. Driving control device.

5. 5. The vehicle driving control device according to claim 4, The controller When it is determined that the specific situation has occurred, the target inter-vehicle distance is shortened at least when a second inter-vehicle distance condition is satisfied, the second inter-vehicle distance condition being that the distance from the host vehicle to the preceding vehicle in the adjacent lane is equal to or shorter than a second threshold distance that is longer than the first threshold distance. Driving control device.

6. 5. The vehicle driving control device according to claim 4, The controller When it is determined that the specific situation has occurred, the target inter-vehicle distance is increased at least when a third inter-vehicle distance condition is satisfied, in which the distance from the host vehicle to the preceding vehicle in the adjacent lane is longer than a second threshold distance that is longer than the first threshold distance. Driving control device.

7. 5. The vehicle driving control device according to claim 4, The controller If it is determined that the specific situation has occurred, a second inter-vehicle distance condition that the distance from the host vehicle to the preceding vehicle in the adjacent lane is equal to or shorter than a second threshold distance that is longer than the first threshold distance; and a third relative speed condition that the speed of the rear vehicle in the adjacent lane is lower than a speed obtained by adding a predetermined vehicle speed threshold to the speed of the host vehicle; and when both of the above conditions are met, the target inter-vehicle distance is shortened. Driving control device.

8. 5. The vehicle driving control device according to claim 4, The controller If it is determined that the specific situation has occurred, a third inter-vehicle distance condition that the distance from the host vehicle to the preceding vehicle in the adjacent lane is longer than a second threshold distance that is longer than the first threshold distance; and a fourth relative speed condition that the speed of the rear vehicle in the adjacent lane is equal to or greater than the speed of the host vehicle plus a predetermined vehicle speed threshold; and when both of the above conditions are met, the target inter-vehicle distance is increased. Driving control device.

9. The vehicle driving control device according to claim 1, The controller the vehicle speed of the host vehicle, the speed of the vehicle behind in the adjacent lane; The vehicle speed of a preceding vehicle in the adjacent lane that is traveling in the adjacent lane and immediately before the following vehicle in the adjacent lane, and a distance from the host vehicle to the preceding vehicle in the adjacent lane; and determining whether the specific situation occurs based on the Driving control device.

10. 1. A vehicle travel control method including a step of performing a following inter-vehicle distance control for traveling a host vehicle so that an inter-vehicle distance between the host vehicle and a target vehicle traveling immediately before the host vehicle is maintained at a predetermined target inter-vehicle distance, The step of executing the following inter-vehicle distance control includes a step of changing the target inter-vehicle distance when a specific situation occurs in which a rear vehicle in an adjacent lane that is adjacent to the lane in which the host vehicle is traveling and that is traveling behind the host vehicle is present and there is a possibility that the rear vehicle in the adjacent lane will cut in between the host vehicle and the vehicle to be followed. Driving control method.

11. A program to be executed by a computer installed in a vehicle, The program is written to the computer. executing a step of executing a following vehicle distance control for driving the host vehicle so that the inter-vehicle distance between the host vehicle and a vehicle to be followed that is traveling immediately in front of the host vehicle is maintained at a predetermined target inter-vehicle distance; Furthermore, During execution of the following inter-vehicle distance control, if a specific situation occurs in which a rear vehicle in an adjacent lane that is adjacent to the lane in which the host vehicle is traveling is present behind the host vehicle and the rear vehicle in the adjacent lane is likely to cut in between the host vehicle and the vehicle to be followed, a step of changing the target inter-vehicle distance is executed. program.

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