Operation support device of vehicle

Abstract

To provide an operation support device of a vehicle that can suppress unnecessary acceleration / deceleration when the vehicle changes a lane.SOLUTION: A run_ECU 14 monitors a preceding vehicle P to determine whether the preceding vehicle changes a lane to a same target lane in synchronization with an own vehicle O, under a starting condition that the preceding vehicle P registered as a leading vehicle L and the own vehicle O are running on the same lane, which mitigates a preceding vehicle registration condition as well as a preceding-vehicle registration releasing condition when the preceding vehicle is being monitored, more than when the preceding vehicle is not being monitored.SELECTED DRAWING: Figure 15

Description

[Technical field]

[0001] The present invention relates to a vehicle driving assistance device that appropriately registers a vehicle traveling ahead of a host vehicle as a preceding vehicle and performs various controls. [Background technology]

[0002] In recent years, many vehicles equipped with driving assistance devices have been put into practical use in the field of automobiles and other vehicles. The driving assistance device basically realizes driving assistance control by executing adaptive cruise control (ACC) and active lane keep centering control (ALKC).

[0003] In the following vehicle distance control, basically, constant speed traveling control and following vehicle distance control are selectively executed. Constant speed traveling control is a control for maintaining the vehicle speed of the host vehicle at a set vehicle speed set by the driver. This constant speed traveling control is selected when a preceding vehicle to be followed is not registered ahead of the host vehicle. On the other hand, following vehicle distance control is a control by the driving support device for maintaining the vehicle distance between the host vehicle and the preceding vehicle at a target vehicle distance. This following vehicle distance control is selected when a preceding vehicle is registered ahead of the host vehicle.

[0004] Here, the registration of the preceding vehicle to be followed is generally cancelled when the vehicle itself or the preceding vehicle starts to change lanes. For example, Patent Document 1 discloses a technique for continuing or cancelling follow-up driving control (i.e., continuing or cancelling the registration of the preceding vehicle) after determining that the preceding vehicle (the vehicle ahead) has issued a direction indication using its turn signal and then the vehicle ahead starts to change lanes. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-173383 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the technology disclosed in the above-mentioned Patent Document 1, the preceding vehicle registration is basically cancelled on the condition that the preceding vehicle starts to change lanes. Therefore, for example, in the technology of Patent Document 1, even if the host vehicle starts to change lanes in the same direction as the preceding vehicle during the transition of the preceding vehicle's lane change, the preceding vehicle registration may be temporarily cancelled unless the driver indicates an intention to continue the following cruise control by an input operation.

[0007] If the preceding vehicle registration is temporarily cancelled in this way, there is a risk that unnecessary acceleration / deceleration control will be performed on the host vehicle due to a temporary switch between follow-up cruise control and constant speed cruise control, for example.

[0008] An object of the present invention is to provide a driving assistance device for a vehicle that can suppress unnecessary acceleration and deceleration when changing lanes. [Means for solving the problem]

[0009] A vehicle driving assistance device according to one embodiment of the present invention comprises a preceding vehicle registration determination means for registering a preceding vehicle traveling in front of the host vehicle as a preceding vehicle based on preset preceding vehicle registration conditions, and for canceling the registration of the preceding vehicle as a preceding vehicle based on preset preceding vehicle registration deregistration conditions, and a preceding vehicle monitoring means for monitoring the preceding vehicle to determine whether the preceding vehicle will make a synchronous lane change to the same target lane as the host vehicle, with a starting condition being that the preceding vehicle registered as the preceding vehicle and the host vehicle are traveling steadily in the same lane, and the preceding vehicle registration determination means relaxes the preceding vehicle registration conditions and the preceding vehicle registration deregistration conditions when the preceding vehicle monitoring is being performed compared to when the preceding vehicle monitoring is not being performed.

[0010] A vehicle driving assistance device according to another aspect of the present invention includes a processor, which registers a preceding vehicle traveling in front of the host vehicle as a preceding vehicle based on preset preceding vehicle registration conditions, and performs a preceding vehicle registration determination to cancel the registration of the preceding vehicle as a preceding vehicle based on preset preceding vehicle registration deregistration conditions, performs preceding vehicle monitoring to determine whether the preceding vehicle will make a synchronous lane change to the same target lane as the host vehicle, with a starting condition being that the preceding vehicle registered as the preceding vehicle and the host vehicle are traveling steadily in the same lane, and when the preceding vehicle monitoring is being performed in the preceding vehicle registration determination, the preceding vehicle registration conditions are relaxed compared to when the preceding vehicle monitoring is not being performed, and the preceding vehicle registration deregistration conditions are relaxed. Effect of the Invention

[0011] According to the vehicle driving assistance device of the present invention, unnecessary acceleration / deceleration during lane changing can be suppressed. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing a vehicle driving assistance device; [Diagram 2] FIG. 2 is an explanatory diagram showing the transition of the driving state of the host vehicle and the vehicle ahead; [Diagram 3] FIG. 2 is an explanatory diagram showing conditions for determining whether the vehicle in question and the vehicle in front are in a steady driving state; [Figure 4] FIG. 2 is an explanatory diagram showing conditions for determining lane change states of the host vehicle and the vehicle ahead; [Diagram 5] FIG. 2 is an explanatory diagram showing conditions for determining the target lane driving state of the host vehicle and the vehicle ahead; [Figure 6] FIG. 13 is an explanatory diagram showing the cancellation conditions for the registration of a preceding vehicle. [Figure 7] FIG. 13 is an explanatory diagram showing the cancellation conditions for the registration of a preceding vehicle. [Figure 8] FIG. 13 is an explanatory diagram showing the cancellation conditions for the registration of a preceding vehicle. [Figure 9] Flowchart showing a routine for determining the running state of a vehicle (part 1) [Figure 10]Flowchart showing a routine for determining the running state of the vehicle (part 2) [Figure 11] Flowchart showing a routine for determining the running state of the vehicle (part 3) [Figure 12] Flowchart showing the routine for determining the driving state of the vehicle ahead (part 1) [Figure 13] Flowchart showing the routine for determining the driving state of the vehicle ahead (part 2) [Figure 14] Flowchart showing the routine for determining the driving state of the vehicle ahead (part 3) [Figure 15] Flowchart showing the synchronous lane change monitoring target determination routine (part 1) [Figure 16] Flowchart showing the synchronous lane change monitoring target determination routine (part 2) [Figure 17] Flowchart showing the cancellation condition judgment subroutine for synchronous lane change monitoring (part 1) [Figure 18] Flowchart showing the cancellation condition judgment subroutine for synchronous lane change monitoring (part 2) [Figure 19] Flowchart showing the cancellation condition judgment subroutine for synchronous lane change monitoring (part 3) [Figure 20] Flowchart showing the cancellation condition judgment subroutine for synchronous lane change monitoring (part 4) [Figure 21] Flowchart showing the cancellation condition judgment subroutine for synchronous lane change monitoring (part 5) [Figure 22] Flowchart showing the cancellation condition judgment subroutine for synchronous lane change monitoring (part 6) [Figure 23] Flowchart showing preceding vehicle registration determination routine (part 1) [Figure 24] Flowchart showing preceding vehicle registration determination routine (part 2) [Diagram 25] Flowchart showing preceding vehicle registration determination routine (part 3) [Figure 26] Flowchart showing the following vehicle distance control routine [Figure 27]FIG. 2 is an explanatory diagram illustrating an example of a driving environment ahead when the vehicle is in a steady driving state; [Figure 28] FIG. 2 is an explanatory diagram illustrating an example of a driving environment ahead when the vehicle is in a lane change state; [Figure 29] FIG. 2 is an explanatory diagram illustrating an example of a driving environment ahead when the vehicle is in a target lane driving state; [Diagram 30] FIG. 2 is an explanatory diagram illustrating a driving environment in front of the host vehicle when the host vehicle is in a lane change state; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to one embodiment of the present invention, and Fig. 1 is a schematic diagram showing a vehicle driving support device.

[0014] 1, the driving assistance device 1 is configured to include a camera unit 10. The camera unit 10 is fixed to the center of the upper front part of the interior of a vehicle (host vehicle) O, for example.

[0015] The camera unit 10 includes a stereo camera 11 as an imaging means, an image processing unit (IPU) 12, an image recognition unit (image recognition_ECU) 13, and a driving control unit (driving_ECU) 14.

[0016] The stereo camera 11 has a main camera 11a and a sub camera 11b. The main camera 11a and the sub camera 11b are configured with imaging elements such as CMOS. The main camera 11a and the sub camera 11b are arranged, for example, at symmetrical positions on either side of the center in the vehicle width direction. As a result, the main camera 11a and the sub camera 11b take stereo images of the driving environment in front of the vehicle from different viewpoints at a predetermined imaging period that is synchronized with each other.

[0017] The IPU 12 processes the driving environment images captured by the stereo camera 11 in a predetermined manner and detects the edges of various objects such as three-dimensional objects and lane markings on the road surface displayed in the images. The IPU 12 also obtains distance information from the positional deviation of corresponding edges on the left and right images. As a result, the IPU 12 generates image information including distance information (distance image information).

[0018] The image recognition_ECU 13 recognizes lane markings that divide lanes on a road based on distance image information received from the IPU 12, etc. For example, the image recognition_ECU 13 calculates the curvature [1 / m] of the left and right markings that divide each lane on the road, and the width between the left and right markings (lane width). Furthermore, the image recognition_ECU 13 calculates the lane width from the difference between the curvatures of the left and right markings. Through these lane marking recognition processes, the image recognition_ECU 13 recognizes lanes on the road, including the lane on which the host vehicle O is traveling (host vehicle driving lane).

[0019] Furthermore, the image recognition_ECU 13 performs predetermined pattern matching on the distance image information. As a result, the image recognition_ECU 13 recognizes three-dimensional objects such as guardrails and curbs extending along the road, and surrounding vehicles traveling on the road. Here, the image recognition_ECU 13 recognizes, for example, the type of the three-dimensional object, the distance to the three-dimensional object, the speed of the three-dimensional object, and the relative speed between the three-dimensional object and the vehicle O.

[0020] Thus, in this embodiment, the stereo camera 11, the IPU 12, and the image recognition_ECU 13 correspond to a specific example of a driving environment recognition means (driving environment recognition unit).

[0021] Various pieces of information recognized by the image recognition_ECU 13 are output to a traveling_ECU (traveling_ECU) 14 as traveling environment information.

[0022] The driving_ECU 14 is a control unit for overall control of the driving assistance device 1.

[0023] A locator unit 20, a left front side sensor 21lf, a right front side sensor 21rf, a left rear side sensor 21lr, and a right rear side sensor 21rr are connected as various sensors to the travel_ECU 14. In addition, various control units, such as an engine control unit (E / G_ECU) 22, a transmission control unit (T / M_ECU) 23, a brake control unit (BK_ECU) 24, and a power steering control unit (PS_ECU) 25, are connected to the travel_ECU 14 via an in-vehicle communication line such as a CAN (Controller Area Network).

[0024] The left front side sensor 21lf and the right front side sensor 21rf are, for example, constituted by millimeter wave radars. The left front side sensor 21lf and the right front side sensor 21rf are, for example, disposed on the left and right sides of the front bumper, respectively. The left front side sensor 21lf and the right front side sensor 21rf detect, as driving environment information, three-dimensional objects existing in the areas diagonally forward and to the left and right and to the sides of the vehicle O, which are difficult to recognize in the image of the stereo camera 11.

[0025] The left rear side sensor 21lr and the right rear side sensor 21rr are, for example, constituted by millimeter wave radars. The left rear side sensor 21lr and the right rear side sensor 21rr are, for example, disposed on the left and right sides of the rear bumper, respectively. The left rear side sensor 21lr and the right rear side sensor 21rr detect, as driving environment information, three-dimensional objects present in the left and right diagonal lateral and rear areas of the vehicle O that are difficult to recognize by the left front side sensor 21lf and the right front side sensor 21rf.

[0026] Here, when each radar 21 is composed of a millimeter wave radar, the millimeter wave radar mainly detects three-dimensional objects such as a vehicle traveling alongside or following the vehicle by analyzing the reflected waves from the object in response to the outputted radio wave. Specifically, each radar detects the width of the three-dimensional object, the position of the representative point of the three-dimensional object (the relative position with respect to the vehicle O), the speed, etc. as information about the three-dimensional object.

[0027] Thus, in this embodiment, the left front side sensor 21lf, the right front side sensor 21rf, the left rear side sensor 21lr, and the right rear side sensor 21rr correspond to a specific example of a driving environment recognition means (driving environment recognition unit) that recognizes driving environment information outside the vehicle.

[0028] The locator unit 20 includes a GNSS sensor 20a and a high-precision road map database (road map DB) 20b.

[0029] The GNSS sensor 20a receives positioning signals transmitted from a plurality of positioning satellites, thereby determining the position (latitude, longitude, altitude, etc.) of the host vehicle O.

[0030] The road map DB 20b is a large-capacity storage medium such as a HDD. High-precision road map information (dynamic map) is stored in this road map DB 20b. The road map information includes, for example, lane data required for autonomous driving, such as lane width data, lane center position coordinate data, lane travel azimuth data, and speed limit data. The lane data is stored at intervals of several meters for each lane on the road map. Furthermore, the road map DB 20b stores, for example, traffic light data as data associated with the lane data.

[0031] For example, based on a request signal from the driving_ECU 14, the road map DB 20b outputs road map information of a set range based on the vehicle position measured by the GNSS sensor 20a to the driving_ECU 14 as driving environment information.

[0032] Thus, in this embodiment, locator unit 20 corresponds to a specific example of a driving environment recognition means (driving environment recognition unit).

[0033] A throttle actuator 32 for an electronically controlled throttle and the like are connected to an output side of the E / G_ECU 22. In addition, various sensors such as an accelerator sensor (not shown) are connected to an input side of the E / G_ECU 22.

[0034] The E / G_ECU 22 performs drive control for the throttle actuator 32 etc. based on control signals from the travel_ECU 14 or detection signals from various sensors. In this way, the E / G_ECU 22 adjusts the amount of intake air for the engine to generate a desired engine output. The E / G_ECU 22 also outputs signals such as the accelerator opening degree detected by the various sensors to the travel_ECU 14.

[0035] The output side of the T / M_ECU 23 is connected to a hydraulic control circuit 33. Furthermore, various sensors such as a shift position sensor (not shown) are connected to the input side of the T / M_ECU 23. The T / M_ECU 23 performs drive control of the hydraulic control circuit 33 and the like based on an engine torque signal estimated by the E / G_ECU 22 and detection signals from various sensors. As a result, the T / M_ECU 23 operates friction engagement elements, pulleys, and the like provided in the automatic transmission to shift the engine output at a desired gear ratio. Furthermore, the T / M_ECU 23 outputs signals such as the shift position detected by the various sensors to the travel_ECU 14.

[0036] A brake actuator 34 for adjusting the brake fluid pressure output to the brake wheel cylinders provided on the respective wheels is connected to the output side of the BK_ECU 24. In addition, various sensors such as a brake pedal sensor, a yaw rate sensor, a longitudinal acceleration sensor, and a vehicle speed sensor (not shown) are connected to the input side of the BK_ECU 24.

[0037] The BK_ECU 24 performs drive control for the brake actuator 34, etc., based on control signals from the travel_ECU 14 or detection signals from various sensors. As a result, the BK_ECU 24 appropriately generates braking force on each wheel for performing forced braking control, yaw rate control, etc., on the host vehicle O. In addition, the BK_ECU 24 outputs signals of the brake operation state, yaw rate, longitudinal acceleration, vehicle speed (host vehicle speed), etc., detected by various sensors to the travel_ECU 14.

[0038] An electric power steering motor 35 that applies a steering torque to the steering mechanism by the rotational force of the motor is connected to the output side of the PS_ECU 25. In addition, various sensors such as a steering torque sensor and a steering angle sensor are connected to the input side of the PS_ECU 25.

[0039] The PS_ECU 25 performs drive control for the electric power steering motor 35 and the like based on control signals from the travel_ECU 14 or detection signals from various sensors. As a result, the PS_ECU 25 generates a steering torque for the steering mechanism. The PS_ECU 25 also outputs signals of the steering torque, steering angle, etc. detected by the various sensors to the travel_ECU 14.

[0040] For example, a manual driving mode, and a first driving control mode and a second driving control mode, which are driving control modes, are set in the traveling_ECU 14 as driving modes. Each of these driving modes can be selectively switched in the traveling_ECU 14.

[0041] Here, the manual driving mode is a driving mode that requires the driver to maintain steering. The manual driving mode is a driving mode in which the host vehicle O is driven according to driving operations such as steering, accelerator, and brake operations by the driver.

[0042] Similarly, the first driving control mode is a driving mode that requires the driver to maintain steering. That is, the first driving control mode is a so-called semi-automatic driving mode in which the host vehicle O is driven while reflecting the driving operation by the driver. This first driving control mode is realized, for example, by the driving_ECU 14 outputting various control signals to the E / G_ECU 22, the T / M_ECU 23, the BK_ECU 24, and the PS_ECU 25. In the first driving control mode, for example, adaptive cruise control (ACC), active lane keep centering (ALKC) control, and active lane keep bouncing control are appropriately combined.

[0043] Here, the following distance control is basically performed based on the driving environment information input from the image recognition_ECU 13. This following distance control is basically realized by selectively executing following cruise control and constant speed cruise control.

[0044] For example, when a preceding vehicle L is registered ahead of the host vehicle O based on the driving environment information, the traveling_ECU 14 performs follow-up driving control as part of the following vehicle distance control. In this follow-up driving control, the traveling_ECU 14 sets a target vehicle distance based on the vehicle speed, etc. of the preceding vehicle L. Then, the traveling_ECU 14 performs acceleration / deceleration control to maintain the target vehicle distance.

[0045] On the other hand, when no preceding vehicle L is registered ahead of the host vehicle O, the travel_ECU 14 performs constant speed travel control as part of the following inter-vehicle distance control. In this constant speed travel control, the travel_ECU 14 performs acceleration / deceleration control on the host vehicle O, with the set vehicle speed Vset input by the driver as the target vehicle speed. In this way, the travel_ECU 14 maintains the vehicle speed of the host vehicle O at the set vehicle speed Vset.

[0046] Furthermore, the lane center keeping control and lane departure suppression control are basically performed based on driving environment information input from at least one of the image recognition_ECU 13 and the locator unit 20. That is, the driving_ECU 14 sets a target travel path along the left and right lane markings in the center of the host vehicle's travel lane based on, for example, lane marking information included in the driving environment information. Then, the driving_ECU 14 maintains the host vehicle O in the center of the lane by performing feedforward control and feedback control for steering based on the target travel path.

[0047] The second driving control mode is a driving mode in which the host vehicle O is driven without the driver's steering, accelerator operation, and brake operation. That is, the second driving control mode is a so-called automatic driving mode in which the host vehicle O is driven autonomously without the driver's driving operation. This second driving control mode is realized, for example, by the driving_ECU 14 outputting various control signals to the E / G_ECU 22, the BK_ECU 24, and the PS_ECU 25. In the second driving control mode, a preceding vehicle following control, a lane centering control, a lane departure suppression control, and the like are mainly performed in appropriate combination. Furthermore, in order to drive the host vehicle O according to a target route (route map information), an automatic lane changing (ALC) control is performed as appropriate in the second driving control mode.

[0048] The lane change control is basically performed based on the driving environment information input from at least one of the image recognition_ECU 13 and the locator unit 20. That is, the driving_ECU 14 sets a target lateral position in a lane adjacent to the host vehicle's driving lane based on information included in the driving environment information. Furthermore, the driving_ECU 14 sets a target route from the target route of the host vehicle O to the target lateral position. Then, the driving_ECU 14 performs steering control along the target route on the condition that no parallel running vehicle or following vehicle is detected in the adjacent lane by the sensors 21fl, 21fr, 21rl, 21rr.

[0049] Next, the following vehicle distance control in this embodiment will be specifically described.

[0050] During this following vehicle distance control, the travel_ECU 14 classifies the travel state of the host vehicle O. For example, the travel_ECU 14 basically classifies the travel state of the host vehicle O into one of a steady travel state, a lane change state, and a target lane travel state (see FIG. 2). These travel states are determined based on, for example, lateral movement information of the host vehicle O and relative position information between the host vehicle O and a lane marking.

[0051] The steady driving state refers to a state in which the host vehicle O is steadily driving on the current lane. For example, when the host vehicle O continues to move laterally without continuous movement for a set time or more (for example, one second or more), the driving_ECU 14 determines that the host vehicle O is in a steady driving state. For this reason, the driving_ECU 14 calculates a lateral movement amount Δx of the host vehicle O based on, for example, the distances xl and xr (see FIG. 3) from the host vehicle O to the left and right lane markings. Then, when the lateral movement amount Δx continues to be less than a set threshold for a set time or more, the driving_ECU 14 determines that the host vehicle O is in a steady driving state.

[0052] The lane change state refers to a transitional state in which the host vehicle O changes lanes from a lane in which the host vehicle O is steadily traveling (the host vehicle's lane) to an adjacent target lane. For example, as shown in FIG. 4, when the turn signal of the host vehicle O is on, the travel_ECU 14 indirectly determines that the host vehicle O moves laterally toward a lane marking. As a result, the travel_ECU 14 determines that the host vehicle O is in a lane change state. Alternatively, for example, as shown in FIG. 4, when the predicted travel path of the host vehicle O intersects with a lane marking in the vicinity of the host vehicle O, the travel_ECU 14 determines that the host vehicle O is in a lane change state. Here, the predicted travel path of the host vehicle O can be calculated based on, for example, the steering angle of the host vehicle O. However, when the host vehicle O is undergoing an automated lane change control, the target travel path of the automated lane change control is used as the predicted travel path.

[0053] The target lane driving state refers to a state in which the host vehicle O is driving on the target lane. For example, as shown in Fig. 5, when the state in which the entire host vehicle O enters the target lane due to a lane change continues for a set number of frames or more (for example, five frames or more), the driving_ECU 14 determines that the host vehicle O is in the target lane driving state. When the host vehicle O in the target lane driving state satisfies the above-mentioned determination criteria for the steady driving state, the driving_ECU 14 determines that the host vehicle O has transitioned to a constant speed driving state, with the target lane as the new host vehicle driving lane.

[0054] Further, the travel_ECU 14 extracts a vehicle ahead P traveling ahead of the host vehicle O based on the traveling environment information. Here, the vehicle ahead P in this embodiment is a vehicle moving in substantially the same direction as the host vehicle O. The concept of the vehicle ahead P also includes a preceding vehicle L, which will be described later.

[0055] Then, when a vehicle in front is extracted, the travel_ECU 14 classifies the travel state of the vehicle in front P. For example, the travel_ECU 14 basically classifies the travel state of the vehicle in front P into one of a steady travel state, a lane change state, and a target lane travel state (see FIG. 2). These travel states are determined based on, for example, lateral movement information of the vehicle in front P and the relative positional relationship between the vehicle in front P and the lane markings.

[0056] The steady driving state refers to a state in which the vehicle P in front is steadily driving on the current lane. The driving_ECU 14 determines whether the vehicle P in front is in a steady driving state based on, for example, the same determination criteria as those for the host vehicle O.

[0057] The lane-changing state refers to a transitional state in which the vehicle P in front changes lanes from the lane in which it is steadily traveling to an adjacent target lane. For example, as shown in Fig. 4, the driving_ECU 14 determines that the vehicle P in front is in a lane-changing state when the vehicle P in front is moving laterally continuously for a set number of frames or more (for example, five frames or more). Alternatively, for example, as shown in Fig. 4, the driving_ECU 14 determines that the vehicle P in front is in a lane-changing state when the center of the vehicle P in front crosses a lane dividing line.

[0058] The target lane driving state refers to a state in which the preceding vehicle P is driving on the target lane. The driving_ECU 14 determines whether the preceding vehicle P is in the target lane driving state based on, for example, the same determination criteria as those for the host vehicle O.

[0059] Furthermore, when a preceding vehicle P is extracted, the travel_ECU 14 judges whether or not to register the preceding vehicle P as a preceding vehicle L. Such preceding vehicle registration judgment is performed based on, for example, the relationship between the host vehicle O and the preceding vehicle P shown in the following (1) to (3).

[0060] (1) The inter-vehicle distance Dv (see FIG. 6, for example) between the host vehicle O and the vehicle in front P is equal to or less than a preset threshold value Dvth.

[0061] (2) The vehicle speed Vp of the preceding vehicle P is equal to or lower than the set vehicle speed Vset of the constant speed cruise control of the host vehicle O.

[0062] (3) The vehicle O and the vehicle in front P are traveling steadily in the same lane.

[0063] The travel_ECU 14 then registers the preceding vehicle P as the preceding vehicle L, with the preceding vehicle registration conditions being that all of the relationships (1) to (3) are satisfied.

[0064] On the other hand, when the preceding vehicle P is registered as the preceding vehicle L, the travel_ECU 14 cancels the registration of the preceding vehicle L when the preceding vehicle P no longer satisfies at least one of the conditions (1) to (3).

[0065] When the preceding vehicle L is registered, the travel_ECU 14 executes the following travel control.

[0066] In this follow-up running control, the traveling_ECU 14 calculates a target acceleration a1 for causing the host vehicle speed Vo to converge to the set vehicle speed Vset. When calculating the target acceleration a1, the traveling_ECU 14 calculates a difference Vrel (=Vset-Vo) between the host vehicle speed Vo and the set vehicle speed Vset. The traveling_ECU 14 then calculates the target acceleration a1 according to the difference Vsrel by referring to a preset map or the like.

[0067] Furthermore, during follow-up driving control, the traveling_ECU 14 calculates a target acceleration a2 for converging the inter-vehicle distance Dv between the host vehicle O and the preceding vehicle L to the target inter-vehicle distance Dtrg. When calculating the target acceleration a2, the traveling_ECU 14 calculates the target inter-vehicle distance Dtrg according to the host vehicle speed Vo by referring to a preset map or the like. The traveling_ECU 14 also calculates a difference ΔD (=Dtrg-Dv) between the target inter-vehicle distance Dtrg and the inter-vehicle distance Dv. The traveling_ECU 14 also calculates a relative speed Vrel between the preceding vehicle speed Vl and the host vehicle speed Vo. The traveling_ECU 14 then calculates the target acceleration a2 according to the difference ΔD and the relative speed Vrel by referring to a preset map or the like.

[0068] After calculating the target accelerations a1, a2, the travel_ECU 14 performs acceleration / deceleration control on the host vehicle O using the larger value of the target accelerations a1, a2.

[0069] On the other hand, when the registration of the preceding vehicle L is cancelled, the travel_ECU 14 executes constant speed travel control.

[0070] In this constant speed cruise control, the travel_ECU 14 calculates the target acceleration a1 in the same manner as in the above-mentioned follow-up cruise control. Then, the travel_ECU 14 performs acceleration / deceleration control on the host vehicle O using the target acceleration a1.

[0071] Here, when the registration of the preceding vehicle is cancelled due to the host vehicle O changing lanes, the traveling_ECU 14 executes the lane change acceleration control until the host vehicle speed Vo reaches the set vehicle speed Vset. In this lane change acceleration control, the traveling_ECU 14 calculates a target acceleration a1' by correcting the target acceleration a1 of the constant speed traveling control to the increasing side. For example, the traveling_ECU 14 calculates the target acceleration a1' by multiplying the target acceleration a1 by a predetermined gain. Alternatively, the traveling_ECU 14 calculates the target acceleration a1' by adding a predetermined acceleration to the target acceleration a1. In this way, the traveling_ECU 14 enables smooth acceleration when overtaking the preceding vehicle L by changing lanes.

[0072] Incidentally, the lanes in which the host vehicle O and the preceding vehicle L are traveling become temporarily unclear when changing lanes. Therefore, when the host vehicle O and the preceding vehicle L (vehicle P in front) change lanes approximately synchronously within a predetermined time, the preceding vehicle L is switched between deregistration and registration (re-registration) in a short time. If lane change acceleration control is temporarily executed due to such a change in the registration status of the preceding vehicle L, unnecessary acceleration and deceleration may occur in the host vehicle O. Therefore, in order to prevent the change in the registration status of the preceding vehicle L due to a synchronous lane change, the travel_ECU 14 partially changes the registration conditions and deregistration conditions of the preceding vehicle L.

[0073] Specifically, the traveling_ECU 14 starts monitoring the vehicle in front when the basic starting conditions are that the vehicle in front P is registered as a preceding vehicle L and that the steady traveling state of the host vehicle O and the vehicle in front P is maintained for a set time (e.g., 1 second). This vehicle in front monitoring is monitoring whether the vehicle in front P will make a synchronous lane change to the same target lane as the host vehicle O. In this embodiment, while performing vehicle in front monitoring, the traveling_ECU 14 sets the flag Fslc to "1".

[0074] Such monitoring of the vehicle in front P is basically released when the driving states of the host vehicle O and the vehicle in front P transition to a state in which they are traveling in the same target lane (target lane driving state). However, when at least one of various cancellation conditions preset for the host vehicle O and the vehicle in front P is satisfied, the monitoring of the vehicle in front is released. The cancellation conditions for the monitoring of the vehicle in front are set according to the driving states of the host vehicle O and the vehicle in front P, respectively.

[0075] When the preceding vehicle monitoring is being performed, the travel_ECU 14 relaxes the preceding vehicle registration conditions compared to when the preceding vehicle monitoring is not being performed.

[0076] For example, even if the above condition (3) is not met, the travel_ECU 14 exceptionally registers the preceding vehicle if the above conditions (1) and (2) are met.

[0077] That is, when the vehicle-in-front monitoring is being performed and the registration of the vehicle-in-front P as the preceding vehicle L is cancelled, the travel_ECU 14 registers the vehicle-in-front P as the preceding vehicle L on the condition that the vehicle-in-front P is already changing lanes to the same target lane when the host vehicle O starts to change lanes. Here, the case where the vehicle-in-front P is already changing lanes to the same target lane when the host vehicle O starts to change lanes corresponds to the case where the host vehicle O and the vehicle-in-front P are making synchronous lane changes. Note that the case where the vehicle-in-front P is changing lanes refers to, for example, the case where the vehicle-in-front P has invaded the target lane by a predetermined amount or more (for example, 350 mm or more).

[0078] In addition, the travel_ECU 14 relaxes the preceding vehicle registration cancellation conditions when the preceding vehicle monitoring is being performed, compared with when the preceding vehicle monitoring is not being performed.

[0079] For example, even if the above condition (3) is not met, the travel_ECU 14 exceptionally maintains the preceding vehicle registration in a predetermined manner if the above conditions (1) and (2) are met.

[0080] That is, in a case where vehicle-in-front monitoring is being performed and vehicle-in-front P is registered as a preceding vehicle L, when the host vehicle O starts to change lanes, the travel_ECU 14 suspends the cancellation of the registration of the vehicle-in-front P as the preceding vehicle L until a set time T1 (e.g., 5 seconds) has elapsed. Then, if the vehicle-in-front P starts to change lanes before the set time T1 has elapsed, the travel_ECU 14 maintains the registration of the vehicle-in-front P as the preceding vehicle L. On the other hand, if the vehicle-in-front P does not start to change lanes before the set time T1 has elapsed, the travel_ECU 14 cancels the registration of the vehicle-in-front P as the preceding vehicle L. Here, the case where the vehicle-in-front P starts to change lanes before the set time T1 has elapsed after the host vehicle O started to change lanes corresponds to the case where the host vehicle O and the vehicle-in-front P are making synchronous lane changes.

[0081] Furthermore, in a case where vehicle-in-front monitoring is being performed and vehicle-in-front P is registered as a preceding vehicle L, when vehicle-in-front P starts to change lanes, the travel_ECU 14 suspends deregistration of vehicle-in-front P as the preceding vehicle L until a set time T2 (e.g., 2 seconds) has elapsed. Then, if the host vehicle O starts to change lanes before the set time T2 has elapsed, the travel_ECU 14 maintains the registration of vehicle-in-front P as the preceding vehicle L. On the other hand, if the host vehicle O does not start to change lanes before the set time T2 has elapsed, the travel_ECU 14 cancels the registration of vehicle-in-front P as the preceding vehicle L. Here, a case where vehicle-in-front P starts to change lanes before the set time T2 has elapsed since vehicle-in-front P started to change lanes corresponds to a case where vehicle-in-front O and vehicle-in-front P are making synchronous lane changes.

[0082] Thus, in this embodiment, the driving_ECU14 corresponds to a specific example of a preceding vehicle extraction means, a preceding vehicle registration determination means, a first driving state classification means, a second driving state classification means, a preceding vehicle monitoring means, a synchronous lane change determination means, and a following vehicle distance control means.

[0083] Next, the running state determination for the host vehicle O will be described with reference to a flow chart of a running state determination routine shown in Figures 9 to 11. This routine is repeatedly executed by the travel_ECU 14 at set time intervals.

[0084] When the routine starts, in step S101, the driving_ECU 14 checks whether the currently classified driving state of the host vehicle O is a steady driving state.

[0085] Then, in step S101, when it is determined that the traveling state of the host vehicle O is not a steady traveling state (step S101: NO), the traveling_ECU 14 proceeds to step S108.

[0086] On the other hand, when it is determined in step S101 that the traveling state of the host vehicle O is a steady traveling state (step S101: YES), the traveling_ECU 14 proceeds to step S102.

[0087] In step S102, the travel_ECU 14 checks whether the turn signal of the host vehicle O is on or not.

[0088] Then, in step S102, if it is determined that the turn signal is not turned on (step S102: NO), the traveling_ECU 14 proceeds to step S107.

[0089] On the other hand, when it is determined in step S102 that the turn signal is on (step S102: YES), the traveling_ECU 14 proceeds to step S103.

[0090] In step S103, the traveling_ECU 14 calculates the host vehicle's predicted traveling path. For example, when the manual driving mode or the first driving control mode is selected as the driving mode of the host vehicle O, the traveling_ECU 14 calculates the host vehicle's predicted traveling path based on the steering angle of the host vehicle O. Also, for example, when the second driving control mode is selected as the driving mode of the host vehicle O, the traveling_ECU 14 uses the target traveling path calculated for steering control of the host vehicle O as the predicted traveling path.

[0091] In the next step S104, the travel_ECU 14 checks whether the predicted travel path of the host vehicle intersects with a lane marking.

[0092] Then, in step S104, when it is determined that the host vehicle's predicted traveling path does not intersect with a lane marking (step S104: NO), the traveling_ECU 14 proceeds to step S107.

[0093] On the other hand, if it is determined in step S104 that the host vehicle's predicted travel path intersects with a lane marking (step S104: YES), the traveling_ECU 14 proceeds to step S105.

[0094] In step S105, the travel_ECU 14 checks whether or not the distance Di from the host vehicle O to the intersection of the host vehicle's travel path and the lane marking is less than a preset threshold value Dith.

[0095] Then, in step S105, when it is determined that the distance Di is less than the threshold value Dith (step S105: YES), the traveling_ECU 14 proceeds to step S106.

[0096] Then, in step S106, the driving_ECU 14 determines that the driving state of the host vehicle O has transitioned from the steady driving state to the lane change state, and then exits the routine.

[0097] On the other hand, when it is determined in step S105 that the distance Di is equal to or greater than the threshold value Dith (step S105: NO), the traveling_ECU 14 proceeds to step S107.

[0098] When the process proceeds from step S102, step S104, or step S107 to step S107, the driving_ECU 14 exits the routine while maintaining the determination that the driving state of the host vehicle O is a steady driving state.

[0099] In addition, when the process proceeds from step S101 to step S108, the travel_ECU 14 checks whether the currently classified travel state of the host vehicle O is a lane change state.

[0100] Then, in step S108, when it is determined that the traveling state of the host vehicle O is not a lane change state (step S108: NO), the traveling_ECU 14 proceeds to step S113.

[0101] On the other hand, when it is determined in step S108 that the traveling state of the host vehicle O is the lane change state (step S108: YES), the traveling_ECU 14 proceeds to step S109.

[0102] In step S109, the traveling_ECU 14 checks whether or not the entire host vehicle O has entered the target lane due to the lane change.

[0103] Then, in step S109, when it is determined that the entire vehicle has not entered the target lane (step S109: NO), the traveling_ECU 14 proceeds to step S112.

[0104] On the other hand, when it is determined in step S109 that the entire vehicle is within the target lane (step S109: YES), the traveling_ECU 14 proceeds to step S110.

[0105] In step S110, the driving_ECU 14 checks whether the host vehicle O has continued to enter the target lane for a set number of frames or more (for example, five frames or more).

[0106] Then, in step S110, when it is determined that the host vehicle O has continued to be in the target lane for the set number of frames or more since entering the target lane (step S110: YES), the traveling_ECU 14 proceeds to step S111.

[0107] In step S111, the driving_ECU 14 determines that the driving state of the host vehicle O has transitioned from a lane change state to a target lane driving state, and then exits the routine.

[0108] On the other hand, in step S110, when it is determined that the host vehicle O has not continued to enter the target lane for the set number of frames or more since entering the target lane (step S110: NO), the driving_ECU 14 proceeds to step S112.

[0109] When the process proceeds from step S109 or step S110 to step S112, the process exits the routine while maintaining the determination that the vehicle O is in a lane-changing state.

[0110] Furthermore, when the process proceeds from step S108 to step S113, the travel_ECU 14 calculates the lateral movement amount Δx of the host vehicle O with respect to the lane marking.

[0111] In the following step S114, the traveling_ECU 14 checks whether the calculated lateral movement amount Δx is less than a threshold value.

[0112] Then, in step S114, when it is determined that the lateral movement amount Δx is less than the threshold value (step S114: YES), the traveling_ECU 14 proceeds to step S117.

[0113] On the other hand, when it is determined in step S114 that the lateral movement amount Δx is equal to or greater than the threshold value (step S114: NO), the traveling_ECU 14 proceeds to step S115.

[0114] In step S115, the traveling_ECU 14 checks whether or not a state in which the lateral movement amount Δx is equal to or greater than a threshold value has continued for a set time or longer (for example, one second or longer).

[0115] Then, in step S115, if it is determined that the state in which the lateral movement amount Δx is equal to or greater than the threshold value has continued for the set time or longer (step S115: YES), the traveling_ECU 14 proceeds to step S116.

[0116] In step S116, the driving_ECU 14 determines that the driving state of the host vehicle O has transitioned from the target lane driving state to a steady driving state, and then exits the routine.

[0117] On the other hand, in step S115, when it is determined that the state in which the lateral movement amount Δx is equal to or greater than the threshold has not elapsed for the set time or longer (step S115: NO), the traveling_ECU 14 proceeds to step S117.

[0118] When the process proceeds from step S114 or step S115 to step S117, the driving_ECU 14 exits the routine while maintaining the determination that the driving state of the host vehicle O is the target lane driving state.

[0119] Next, the travel condition determination for the preceding vehicle P will be described with reference to a flowchart of a travel condition determination routine shown in Figures 12 to 14. This routine is repeatedly executed by the travel_ECU 14 at set time intervals when the preceding vehicle P is detected ahead of the host vehicle O.

[0120] When the routine starts, the traveling_ECU 14 checks in step S201 whether the currently classified traveling state of the preceding vehicle P is a steady traveling state.

[0121] Then, in step S201, when it is determined that the traveling state of the preceding vehicle P is not a steady traveling state (step S201: NO), the traveling_ECU 14 proceeds to step S209.

[0122] On the other hand, in step S201, when it is determined that the traveling state of the preceding vehicle P is a steady traveling state (step S201: YES), the traveling_ECU 14 proceeds to step S202.

[0123] In step S202, the traveling_ECU 14 calculates the lateral movement amount Δx of the preceding vehicle P with respect to the lane marking.

[0124] In the next step S203, the travel_ECU 14 checks whether the preceding vehicle P is moving laterally. Here, the travel_ECU 14 determines that the preceding vehicle P is moving laterally, for example, when the amount of lateral movement Δx of the preceding vehicle P is equal to or greater than a preset threshold value.

[0125] Then, in step S203, if it is determined that the vehicle-in-front P is not moving laterally (step S203: NO), the travel_ECU 14 proceeds to step S206.

[0126] On the other hand, when it is determined in step S203 that the preceding vehicle P is moving laterally (step S203: YES), the travel_ECU 14 proceeds to step S204.

[0127] In step S204, the travel_ECU 14 checks whether the lateral movement state of the preceding vehicle P has continued for a set number of frames or more (for example, five frames or more).

[0128] Then, in step S204, when it is determined that the lateral movement state of the leading vehicle P is less than the set frame (step S204: NO), the travel_ECU 14 proceeds to step S206.

[0129] On the other hand, in step S204, when it is determined that the lateral movement state of the preceding vehicle P has continued for the consecutive frames or more (step S204: YES), the travel_ECU 14 proceeds to step S205.

[0130] In step S205, the driving_ECU 14 checks whether the vehicle in front P crosses a lane marking.

[0131] Then, in step S205, if it is determined that the vehicle-in-front P intersects with a lane marking (step S205: YES), the travel_ECU 14 proceeds to step S207.

[0132] On the other hand, if it is determined in step S205 that the vehicle-in-front P does not intersect with the lane marking (step S205: NO), the travel_ECU 14 proceeds to step S208.

[0133] When the process proceeds from step S203 or step S204 to step S206, the travel_ECU 14 checks whether or not the center of the vehicle P in front has entered the target lane.

[0134] Then, in step S206, if it is determined that the center of the vehicle-in-front P has not entered the target lane (step S206: NO), the traveling_ECU 14 proceeds to step S208.

[0135] On the other hand, in step S206, when it is determined that the center of the leading vehicle P has entered the target lane (step S206: YES), the traveling_ECU 14 proceeds to step S207.

[0136] When the process proceeds from step S205 or step S206 to step S207, the driving_ECU 14 determines that the driving state of the preceding vehicle P has transitioned from a steady driving state to a lane-changing state, and then exits the routine.

[0137] Also, when the process proceeds from step S205 or step S206 to step S208, the travel_ECU 14 exits the routine while maintaining the determination that the traveling state of the preceding vehicle P is a constant speed traveling state.

[0138] Furthermore, when proceeding from step S201 to step S209, the travel_ECU 14 checks whether the currently classified travel state of the preceding vehicle P is a lane-changing state.

[0139] Then, in step S209, when it is determined that the traveling state of the preceding vehicle P is not a lane change state (step S209: NO), the traveling_ECU 14 proceeds to step S214.

[0140] On the other hand, when it is determined in step S209 that the traveling state of the preceding vehicle P is a lane-changing state (step S209: YES), the traveling_ECU 14 proceeds to step S210.

[0141] In step S210, the driving_ECU 14 checks whether or not the entire body of the leading vehicle P has entered the target lane.

[0142] Then, in step S210, when it is determined that the entire body of the leading vehicle P has not entered the target lane (step S210: NO), the travel_ECU 14 proceeds to step S213.

[0143] On the other hand, when it is determined in step S210 that the entire body of the leading vehicle P is inside the target lane (step S210: YES), the traveling_ECU 14 proceeds to step S211.

[0144] In step S211, the driving_ECU 14 checks whether or not the state in which the entire vehicle P ahead is within the target lane has continued for a set number of frames or more (for example, five frames or more).

[0145] Then, in step S211, when it is determined that the state in which the entire vehicle P ahead is inside the target lane has continued for the set number of frames or more (step S211: YES), the driving_ECU 14 proceeds to step S212.

[0146] In step S212, the driving_ECU 14 determines that the driving state of the preceding vehicle P has transitioned from a lane-changing state to a target lane driving state, and then exits the routine.

[0147] On the other hand, in step S211, when it is determined that the time during which the entire vehicle P in front is within the target lane is less than the set number of frames (step S211: NO), the travel_ECU 14 proceeds to step S213.

[0148] When the process proceeds from step S210 or step S211 to step S213, the driving_ECU 14 exits the routine while maintaining the determination that the driving state of the preceding vehicle P is a lane-changing state.

[0149] Furthermore, when the process proceeds from step S209 to step S214, the travel_ECU 14 calculates the lateral movement amount Δx of the leading vehicle P with respect to the lane marking.

[0150] In the following step S215, the traveling_ECU 14 checks whether the calculated lateral movement amount Δx is less than a threshold value.

[0151] Then, in step S215, when it is determined that the lateral movement amount Δx is less than the threshold value (step S215: YES), the traveling_ECU 14 proceeds to step S218.

[0152] On the other hand, when it is determined in step S215 that the lateral movement amount Δx is equal to or greater than the threshold value (step S215: NO), the traveling_ECU 14 proceeds to step S216.

[0153] In step S216, the traveling_ECU 14 checks whether or not the state in which the lateral movement amount Δx is equal to or greater than the threshold value continues for a set time or longer (for example, one second or longer).

[0154] Then, in step S216, if it is determined that the state in which the lateral movement amount Δx is equal to or greater than the threshold value has continued for the set time or longer (step S216: YES), the traveling_ECU 14 proceeds to step S217.

[0155] In step S217, the driving_ECU 14 determines that the driving state of the preceding vehicle P has transitioned from the target lane driving state to a steady driving state, and then exits the routine.

[0156] On the other hand, if it is determined in step S216 that the state in which the lateral movement amount Δx is equal to or greater than the threshold has not elapsed for the set time or longer (step S216: NO), the traveling_ECU 14 proceeds to step S218.

[0157] When the process proceeds from step S215 or step S216 to step S218, the driving_ECU 14 exits the routine while maintaining the determination that the driving state of the preceding vehicle P is the target lane driving state.

[0158] Next, a determination as to whether or not the preceding vehicle P is to be monitored for synchronous lane change will be described with reference to a flowchart of a synchronous lane change monitoring target determination routine shown in Figures 15 and 16. This routine is repeatedly executed by the travel_ECU 14 at set time intervals.

[0159] When the routine starts, in step S301, the traveling_ECU 14 checks whether or not the monitoring flag Fslc for the preceding vehicle P is set to "1." That is, the traveling_ECU 14 checks whether or not the preceding vehicle P has already been registered as a target for monitoring for synchronous lane change.

[0160] Then, in step S301, when it is determined that the monitoring flag Fslc is set to "1" (step S301: YES), the traveling_ECU 14 proceeds to step S310.

[0161] On the other hand, when it is determined in step S301 that the monitoring flag Fslc is cleared to "0" (step S301: NO), the traveling_ECU 14 proceeds to step S302.

[0162] In step S302, the travel_ECU 14 checks whether the vehicle in front P is registered as a preceding vehicle L or not.

[0163] Then, in step S302, if it is determined that the vehicle in front P is not registered as the preceding vehicle L (step S302: NO), the travel_ECU 14 exits the routine.

[0164] On the other hand, when it is determined in step S302 that the preceding vehicle P is registered as the preceding vehicle L (step S302: YES), the travel_ECU 14 proceeds to step S303.

[0165] In step S303, the traveling_ECU 14 checks whether the traveling state of the host vehicle O is a steady traveling state.

[0166] Then, in step S303, when it is determined that the traveling state of the host vehicle O is not a steady traveling state (step S303: NO), the traveling_ECU 14 exits the routine as it is.

[0167] On the other hand, when it is determined in step S303 that the traveling state of the host vehicle O is a steady traveling state (step S303: YES), the traveling_ECU 14 proceeds to step S304.

[0168] In step S304, the traveling_ECU 14 checks whether the traveling state of the preceding vehicle P (preceding vehicle L) is a steady traveling state.

[0169] Then, in step S304, if it is determined that the traveling state of the preceding vehicle P is not a steady traveling state (step S304: NO), the traveling_ECU 14 exits the routine as it is.

[0170] On the other hand, when it is determined in step S304 that the traveling state of the preceding vehicle P is a steady traveling state (step S304: YES), the traveling_ECU 14 proceeds to step S305.

[0171] In step S305, the travel_ECU 14 checks whether or not the inter-vehicle distance Dv between the host vehicle O and the preceding vehicle P is less than 70 [m], for example.

[0172] Then, in step S305, when it is determined that the inter-vehicle distance Dv is 70 [m] or more, the traveling_ECU 14 exits the routine as it is. In other words, when the inter-vehicle distance Dv is sufficiently large, the synchronous lane change has little effect on the host vehicle O, so the traveling_ECU 14 exits the routine as it is.

[0173] On the other hand, if it is determined in step S305 that the inter-vehicle distance Dv is less than 70 [m], the travel_ECU 14 proceeds to step S306.

[0174] In step S306, the traveling_ECU 14 checks whether the host vehicle speed Vo is equal to or higher than 60 [km / h], for example.

[0175] Then, in step S306, when it is determined that the host vehicle speed Vo is less than 60 [km / h] (step S306: NO), the traveling_ECU 14 exits the routine as it is. That is, when the host vehicle speed Vo is low, traffic congestion or the like is expected, and in such a traveling environment, the synchronous lane change has little effect on the host vehicle O, so the traveling_ECU 14 exits the routine as it is.

[0176] On the other hand, when it is determined in step S306 that the host vehicle speed Vo is equal to or higher than 60 [km / h] (step S306: YES), the traveling_ECU 14 proceeds to step S307.

[0177] Then, in step S307, when it is determined that the preceding vehicle speed Vp is less than 60 [km / h] (step S307: NO), the traveling_ECU 14 exits the routine as it is. That is, when the preceding vehicle speed Vp is low, traffic congestion or the like is expected, and in such a traveling environment, the synchronous lane change has little effect on the host vehicle O, so the traveling_ECU 14 exits the routine as it is.

[0178] On the other hand, in step S307, when it is determined that the preceding vehicle speed Vp is equal to or higher than 60 [km / h] (step S307: YES), the traveling_ECU 14 proceeds to step S308.

[0179] In step S308, the driving_ECU 14 checks whether the turn signal of the host vehicle O is turned off.

[0180] Then, in step S308, when it is determined that the turn signal of the host vehicle O is on (step S308: YES), the traveling_ECU 14 exits the routine as it is. In other words, when the host vehicle O changes lanes immediately after both the host vehicle O and the vehicle in front P enter a steady traveling state, the traveling_ECU 14 exits the routine as it is without setting the monitoring flag Fslc.

[0181] On the other hand, in step S308, when it is determined that the turn signal of the host vehicle O is not turned on (step S308: NO), the travel_ECU 14 proceeds to step S309.

[0182] In step S309, the driving_ECU 14 sets the monitoring flag Fslc to "1", and then proceeds to step S310.

[0183] When the process proceeds from step S301 or step S309 to step S310, the driving_ECU 14 checks whether the driving state of the host vehicle O is classified as the target lane driving state.

[0184] Then, in step S310, when it is determined that the traveling state of the host vehicle O is not the target lane traveling state (step S310: NO), the traveling_ECU 14 proceeds to step S312.

[0185] On the other hand, when it is determined in step S310 that the driving state of the host vehicle O is the target lane driving state (step S310: YES), the driving_ECU 14 proceeds to step S311.

[0186] In step S311, the driving_ECU 14 checks whether the driving state of the preceding vehicle P is classified as the target lane driving state.

[0187] Then, in step S311, when it is determined that the traveling state of the preceding vehicle P is not the target lane traveling state (step S311: NO), the traveling_ECU 14 proceeds to step S312.

[0188] On the other hand, in step S311, when it is determined that the traveling state of the preceding vehicle P is the target lane traveling state (step S311: YES), the traveling_ECU 14 proceeds to step S314. In other words, when it is determined that the traveling states of both the host vehicle O and the preceding vehicle P are the target lane traveling state, the traveling_ECU 14 proceeds to step S314.

[0189] When the process proceeds from step S310 or step S311 to step S312, the driving_ECU 14 performs a cancellation condition determination for the synchronous lane change monitoring. The cancellation condition determination in step S312 is performed according to a flowchart of a cancellation condition determination subroutine, which will be described later.

[0190] In the following step S313, the traveling_ECU 14 checks whether or not a cancellation condition is met.

[0191] Then, in step S313, if it is determined that the cancellation condition is not satisfied (step S313: NO), the traveling_ECU 14 exits the routine as is.

[0192] On the other hand, when it is determined in step S313 that the cancellation condition is satisfied (step S313: YES), the traveling_ECU 14 proceeds to step S314.

[0193] When the process proceeds from step S311 or step S313 to step S314, the traveling_ECU 14 clears the monitoring flag Fslc to "0" and then exits the routine.

[0194] Next, the cancellation condition determination for the synchronous lane change monitoring executed in the above-mentioned step S312 will be described with reference to a flowchart of the cancellation condition determination subroutine shown in Figures 17 to 22. This subroutine is executed in the travel_ECU 14.

[0195] When the subroutine starts, the driving_ECU 14 determines in step S401 whether the host vehicle O and the preceding vehicle P meet the preconditions for synchronous lane change monitoring.

[0196] As prerequisites, for example, the following items (a) to (f) are assumed.

[0197] (a) The predicted collision time TTC with the vehicle P ahead (= (relative distance between the vehicle O and the vehicle P ahead) / (relative speed between the vehicle O and the vehicle ahead)) is, for example, less than 1.5 seconds.

[0198] (b) The steering angle of the host vehicle O is, for example, 45 degrees or more. In such a case, the host vehicle O is expected to turn right or left without changing lanes.

[0199] (c) The detected lane markings are 3 [segments] or less on both sides. In such a case, it is assumed that the lane markings are not sufficiently visible in the first place.

[0200] (d) The lane changing directions of the vehicle O and the vehicle in front P are different.

[0201] (e) On a road where lane changing is prohibited, either the vehicle O or the vehicle in front P is in a lane changing state or is traveling in the target lane.

[0202] (f) After either the vehicle O or the vehicle in front P transitions to a target lane driving state by changing lanes, the other maintains a steady driving state for 4 seconds or more.

[0203] In the following step S402, the traveling_ECU 14 checks whether or not at least one of the cancellation conditions (a) to (f) described above is satisfied.

[0204] Then, in step S402, if it is determined that at least one of the cancellation conditions is satisfied (step S402: YES), the traveling_ECU 14 proceeds to step S407.

[0205] On the other hand, if it is determined in step S402 that all of the cancellation conditions are not satisfied (step S402: NO), the traveling_ECU 14 proceeds to step S403.

[0206] In step S403, the driving_ECU 14 checks whether the driving state of the host vehicle O is a steady driving state (for example, see FIG. 6).

[0207] Then, in step S403, when it is determined that the traveling state of the host vehicle O is not a steady traveling state (step S403: NO), the traveling_ECU 14 proceeds to step S408.

[0208] On the other hand, when it is determined in step S403 that the traveling state of the host vehicle O is a steady traveling state (step S403: YES), the traveling_ECU 14 proceeds to step S404.

[0209] In step S404, the travel_ECU 14 checks whether or not the inter-vehicle distance Dv between the host vehicle O and the preceding vehicle P is equal to or greater than 70 m, for example.

[0210] Then, in step S404, if it is determined that the inter-vehicle distance Dv is equal to or greater than 70 [m] (step S404: YES), the traveling_ECU 14 proceeds to step S407.

[0211] On the other hand, if it is determined in step S404 that the inter-vehicle distance Dv is less than 70 [m] (step S404: NO), the travel_ECU 14 proceeds to step S405.

[0212] In step S405, the traveling_ECU 14 checks whether the host vehicle speed Vo is less than 50 [km / h], for example.

[0213] Then, in step S405, if it is determined that the host vehicle speed Vo is less than 50 [km / h] (step S405: YES), the traveling_ECU 14 proceeds to step S407.

[0214] On the other hand, in step S405, when it is determined that the host vehicle speed Vo is 50 [km / h] or more (step S405: NO), the traveling_ECU 14 proceeds to step S406.

[0215] In step S406, the traveling_ECU 14 checks whether or not the lane markings dividing the traveling lane of the host vehicle O have been switched, even if the traveling state of the host vehicle O is a steady traveling state.

[0216] Then, in step S406, if it is determined that the lane markings have not been switched (step S406: NO), the traveling_ECU 14 proceeds to step S408.

[0217] On the other hand, if it is determined in step S406 that the lane markings have been switched (step S406: YES), the traveling_ECU 14 proceeds to step S417.

[0218] When the process proceeds from step S402, step S404, step S405, or step S406 to step S407, the driving_ECU 14 determines that the cancellation condition for the synchronous lane change monitoring is satisfied, and then proceeds to step S417.

[0219] Furthermore, when the process proceeds from step S403 to step S408, the driving_ECU 14 checks whether or not the driving state of the host vehicle O is classified as a lane change state (see, for example, FIG. 7).

[0220] Then, in step S408, when it is determined that the traveling state of the host vehicle O is not a lane change state (step S408: NO), the traveling_ECU 14 proceeds to step S414.

[0221] On the other hand, when it is determined in step S408 that the traveling state of the host vehicle O is the lane change state (step S408: YES), the traveling_ECU 14 proceeds to step S409.

[0222] In step S409, the traveling_ECU 14 checks whether the host vehicle O is continuously moving laterally in the return direction to the original lane.

[0223] Then, in step S409, when it is determined that the host vehicle O is performing continuous lateral movement in the return direction to the original lane (step S409: YES), the traveling_ECU 14 proceeds to step S413.

[0224] On the other hand, when it is determined in step S409 that the host vehicle O is not making continuous lateral movement in the return direction to the original lane (step S409: NO), the traveling_ECU 14 proceeds to step S410.

[0225] In step S410, the driving_ECU 14 checks whether the host vehicle O remains in the original lane.

[0226] Then, in step S410, when it is determined that the host vehicle O does not remain in the original lane (step S410: NO), the traveling_ECU 14 proceeds to step S417.

[0227] On the other hand, when it is determined in step S410 that the host vehicle O remains in the original lane (step S410: YES), the traveling_ECU 14 proceeds to step S411.

[0228] In step S411, the travel_ECU 14 checks whether or not 4 seconds or more have elapsed since the host vehicle O started to change lanes. Here, the 4 seconds elapsed since the host vehicle O started to change lanes is the upper limit of the time generally required for a driver to change lanes. However, in a lane change by the automatic lane change control, due to the nature of the control, 4 seconds or more may be required since the host vehicle started to change lanes.

[0229] Then, in step S411, if it is determined that 4 seconds have not elapsed since the start of the lane change (step S411: NO), the traveling_ECU 14 proceeds to step S417.

[0230] On the other hand, if it is determined in step S411 that 4 seconds have passed since the start of the lane change (step S411: YES), the traveling_ECU 14 proceeds to step S412.

[0231] In step S412, the driving_ECU 14 checks whether the lane change of the host vehicle O is due to the automatic lane change control.

[0232] Then, in step S412, if it is determined that the lane change is not due to the automatic lane change control (step S412: NO), the traveling_ECU 14 proceeds to step S417.

[0233] On the other hand, when it is determined in step S412 that the lane change is due to the automatic lane change control (step S412: YES), the traveling_ECU 14 proceeds to step S413.

[0234] When the process proceeds from step S409 or step S412 to step S413, the driving_ECU 14 determines that the cancellation condition for the synchronous lane change monitoring is satisfied, and then proceeds to step S417.

[0235] In addition, when proceeding from step S408 to step S414, the traveling_ECU 14 checks whether or not the host vehicle O has made a continuous lateral movement out of the target lane. That is, when the traveling state of the host vehicle O is classified as the target lane traveling state (for example, see FIG. 8), the traveling_ECU 14 checks whether or not the host vehicle O has made a continuous lateral movement out of the target lane.

[0236] Then, in step S414, when it is determined that the host vehicle O is continuously moving laterally outward from the target lane (step S414: YES), the traveling_ECU 14 proceeds to step S416.

[0237] On the other hand, when it is determined in step S414 that the host vehicle O is not continuously moving laterally outside the target lane (step S414: NO), the traveling_ECU 14 proceeds to step S415.

[0238] In step S415, the travel_ECU 14 checks whether the turn signal of the host vehicle O has been turned on again.

[0239] Then, in step S415, if it is determined that the blinker has not been turned on again (step S415: NO), the traveling_ECU 14 proceeds to step S417.

[0240] On the other hand, if it is determined in step S415 that the blinker has been turned on again (step S415: YES), the traveling_ECU 14 proceeds to step S416.

[0241] When the process proceeds from step S414 or step S415 to step S416, the driving_ECU 14 determines that the cancellation condition for the synchronous lane change monitoring is satisfied, and then proceeds to step S417.

[0242] When proceeding to step S417 from step S406, step S407, step S411, step S412, step S413, step S415, or step S416, the travel_ECU 14 checks whether the traveling state of the preceding vehicle P is a steady traveling state (for example, see FIG. 6).

[0243] Then, in step S417, if it is determined that the traveling state of the preceding vehicle P is not a steady traveling state (step S417: NO), the traveling_ECU 14 proceeds to step S421.

[0244] On the other hand, if it is determined in step S417 that the traveling state of the preceding vehicle P is a steady traveling state, the traveling_ECU 14 proceeds to step S418.

[0245] In step S418, the travel_ECU 14 checks whether, for example, two seconds have passed since the registration of the vehicle P in front as the preceding vehicle L was cancelled.

[0246] Then, in step S418, if it is determined that 2 seconds have passed since the registration of the preceding vehicle L was cancelled (step S418: YES), the travel_ECU 14 proceeds to step S420.

[0247] On the other hand, in step S418, if the registration of the preceding vehicle L is still ongoing, or if it is determined that 2 seconds have not elapsed since the registration of the preceding vehicle L was cancelled (step S418: NO), the travel_ECU 14 proceeds to step S419.

[0248] In step S419, the traveling_ECU 14 checks whether the preceding vehicle speed Vp is less than 50 [km / h], for example.

[0249] Then, in step S419, if it is determined that the preceding vehicle speed Vp is less than 50 [km / h] (step S419: YES), the travel_ECU 14 exits the routine.

[0250] On the other hand, if it is determined in step S419 that the preceding vehicle speed Vp is 50 [km / h] or higher (step S419: NO), the travel_ECU 14 proceeds to step S421.

[0251] When the process proceeds from step S418 or step S419 to step S420, the driving_ECU 14 determines that the cancellation condition for the synchronous lane change monitoring is satisfied, and then exits the routine.

[0252] When the process proceeds from step S417 to step S421, the travel_ECU 14 checks whether the traveling state of the preceding vehicle P is a lane-changing state (see FIG. 7, for example).

[0253] Then, in step S421, when it is determined that the traveling state of the preceding vehicle P is not a lane change state (step S421: NO), the traveling_ECU 14 proceeds to step S426.

[0254] On the other hand, when it is determined in step S421 that the traveling state of the preceding vehicle P is a lane-changing state (step S421: YES), the traveling_ECU 14 proceeds to step S422.

[0255] In step S422, the travel_ECU 14 checks whether the vehicle in front P is making a continuous lateral movement in the return direction to the original lane.

[0256] Then, in step S422, if it is determined that the vehicle in front P is making continuous lateral movement in the return direction to the original lane (step S422: YES), the travel_ECU 14 proceeds to step S425.

[0257] On the other hand, when it is determined in step S422 that the vehicle in front P is not making a continuous lateral movement in the return direction to the original lane (step S422: NO), the travel_ECU 14 proceeds to step S423.

[0258] In step S423, the driving_ECU 14 checks whether the vehicle in front P remains in the original lane.

[0259] Then, in step S423, if it is determined that the preceding vehicle P remains in the original lane (step S423: YES), the traveling_ECU 14 proceeds to step S425.

[0260] On the other hand, if it is determined in step S423 that the vehicle-in-front P does not remain in the original lane (step S423: NO), the travel_ECU 14 proceeds to step S424.

[0261] In step S424, the driving_ECU 14 checks whether or not, for example, 4 seconds or more have passed since the preceding vehicle P started to change lanes.

[0262] Then, in step S411, if it is determined that 4 seconds have not elapsed since the start of the lane change (step S424: NO), the traveling_ECU 14 exits the routine.

[0263] On the other hand, if it is determined in step S424 that 4 seconds have elapsed since the start of the lane change (step S424: YES), the traveling_ECU 14 proceeds to step S425.

[0264] When the process proceeds from step S422, step S423, or step S424 to step S425, the driving_ECU 14 determines that the cancellation condition for the synchronous lane change monitoring is satisfied, and then exits the routine.

[0265] Furthermore, when the process proceeds from step S421 to step S426, the travel_ECU 14 checks whether or not the vehicle in front P has made a continuous lateral movement out of the target lane. That is, when the driving state of the vehicle in front P is classified as the target lane driving state (for example, see FIG. 8), the travel_ECU 14 checks whether or not the vehicle in front P has made a continuous lateral movement out of the target lane.

[0266] Then, in step S426, if it is determined that the vehicle-in-front P is making a continuous lateral movement outward from the target lane (step S426: YES), the traveling_ECU 14 proceeds to step S428.

[0267] On the other hand, in step S426, when it is determined that the vehicle-in-front P is not continuously moving laterally outward from the target lane (step S426: NO), the travel_ECU 14 proceeds to step S427.

[0268] In step S427, the travel_ECU 14 checks whether the preceding vehicle P is registered as a parallel running vehicle.

[0269] Then, in step S427, if it is determined that the preceding vehicle P is not registered as a parallel vehicle (step S427: NO), the travel_ECU 14 exits the routine.

[0270] On the other hand, if it is determined in step S427 that the preceding vehicle P is registered as a parallel vehicle (step S427: YES), the travel_ECU 14 proceeds to step S428.

[0271] When the process proceeds from step S426 or step S427 to step S428, the driving_ECU 14 determines that the cancellation condition for the synchronous lane change monitoring is satisfied, and then exits the routine.

[0272] Next, the preceding vehicle registration determination for the preceding vehicle P will be described with reference to a flowchart of a preceding vehicle registration determination routine shown in Figures 23 to 25. This routine is repeatedly executed by the travel_ECU 14 at set time intervals.

[0273] When the routine starts, in step S501, the travel_ECU 14 checks whether the preceding vehicle P is registered as a preceding vehicle L or not.

[0274] Then, in step S501, when it is determined that the vehicle in front P is not registered as the preceding vehicle L (step S501: NO), the travel_ECU 14 proceeds to step S511.

[0275] On the other hand, in step S501, when it is determined that the vehicle in front P is registered as the preceding vehicle L (step S501: YES), the travel_ECU 14 proceeds to step S502.

[0276] In step S502, the driving_ECU 14 checks whether a leading vehicle P is detected ahead of the host vehicle O or not.

[0277] Then, in step S502, if it is determined that the preceding vehicle P has not been detected (step S502: NO), the travel_ECU 14 exits the routine as is.

[0278] On the other hand, if it is determined in step S502 that the preceding vehicle P has been detected (step S502: YES), the travel_ECU 14 proceeds to step S503.

[0279] In step S503, the travel_ECU 14 checks whether the inter-vehicle distance Dv between the host vehicle O and the preceding vehicle P is equal to or less than a threshold value Dvth. Here, the threshold value Dvth is a variable value that is set by referring to a preset map or the like based on the host vehicle speed Vo. Thus, for example, the threshold value Dvth is set to a larger value as the host vehicle speed Vo increases.

[0280] Then, in step S503, when it is determined that the inter-vehicle distance Dv is greater than the threshold value Dvth (step S503: NO), the travel_ECU 14 exits the routine.

[0281] On the other hand, when it is determined in step S503 that the inter-vehicle distance Dv is equal to or smaller than the threshold value Dvth (step S503: YES), the traveling_ECU 14 proceeds to step S504.

[0282] In step S504, the traveling_ECU 14 checks whether the preceding vehicle speed Vp is equal to or lower than the set vehicle speed Vset of the host vehicle O.

[0283] Then, in step S504, when it is determined that the preceding vehicle speed Vp is greater than the set vehicle speed Vset (step S504: NO), the traveling_ECU 14 exits the routine as is.

[0284] On the other hand, when it is determined in step S504 that the preceding vehicle speed Vp is equal to or lower than the set vehicle speed Vset (step S504: NO), the traveling_ECU 14 proceeds to step S505.

[0285] In step S505, the traveling_ECU 14 checks whether or not the host vehicle O and the preceding vehicle P are traveling in the same lane.

[0286] Then, in step S505, if it is determined that both vehicles are not traveling in the same lane (step S505: NO), the traveling_ECU 14 proceeds to step S507.

[0287] On the other hand, if it is determined in step S505 that both vehicles are traveling on the same lane (step S505: YES), the traveling_ECU 14 proceeds to step S506.

[0288] In step S506, the traveling_ECU 14 checks whether the traveling states of both the host vehicle O and the preceding vehicle P are constant speed traveling states.

[0289] Then, in step S506, if it is determined that the traveling state of both vehicles is a constant speed traveling state (step S506: YES), the traveling_ECU 14 proceeds to step S510.

[0290] On the other hand, in step S506, when it is determined that the traveling state of at least one of the vehicles is not a constant speed traveling state (step S506: NO), the traveling_ECU 14 proceeds to step S507.

[0291] In step S507, the traveling_ECU 14 checks whether the monitoring flag Fslc is set to "1." That is, the traveling_ECU 14 checks whether the preceding vehicle P is a target of synchronous lane change monitoring and whether the preceding vehicle registration condition for the preceding vehicle P is relaxed.

[0292] Then, in step S507, if it is determined that the monitoring flag Fslc is cleared to "0" (step S507: NO), the traveling_ECU 14 exits the routine as is.

[0293] On the other hand, if it is determined in step S507 that the monitoring flag Fslc is set to "1" (step S507: YES), the traveling_ECU 14 proceeds to step S508.

[0294] In step S508, the driving_ECU 14 checks whether the driving state of the host vehicle O has transitioned to a lane change state.

[0295] Then, in step S508, when it is determined that the traveling state of the host vehicle O has not transitioned to a lane change state (step S508: NO), the traveling_ECU 14 exits the routine as it is.

[0296] On the other hand, when it is determined in step S508 that the traveling state of the host vehicle O has transitioned to a lane change state (step S508: YES), the traveling_ECU 14 proceeds to step S509.

[0297] In step S509, the traveling_ECU 14 checks whether or not a part of the vehicle P in front has entered the target lane. More specifically, the traveling_ECU checks whether or not the vehicle P in front has entered the target lane that is the same as the lane into which the host vehicle O is to change lanes, and whether or not the amount of intrusion of the vehicle P in front into the target lane is, for example, 350 mm or more.

[0298] Then, in step S509, if it is determined that a part of the vehicle P in front has not entered the target lane, the driving_ECU 14 exits the routine.

[0299] On the other hand, if it is determined in step S509 that a part of the preceding vehicle P has entered the target lane, the driving_ECU 14 proceeds to step S510.

[0300] In other words, if the driving state of the host vehicle O transitions to a lane change state (step S508: YES) and part of the vehicle in front P has entered the target lane (step S509: YES), the driving_ECU 14 determines that the host vehicle O and the vehicle in front P are performing a synchronous lane change, and proceeds to step S510.

[0301] When the process proceeds from step S506 or step S509 to step S510, the travel_ECU 14 registers the preceding vehicle P as the preceding vehicle L, and then exits the routine.

[0302] Furthermore, when the process proceeds from step S510 to step S511, the travel_ECU 14 checks whether or not the inter-vehicle distance Dv between the host vehicle O and the preceding vehicle P is equal to or less than the threshold value Dvth. As described in the above step S503, the threshold value Dvth is a variable value that is set based on, for example, the host vehicle speed Vo.

[0303] Then, in step S511, when it is determined that the inter-vehicle distance Dv is greater than the threshold value Dvth (step S511: NO), the travel_ECU 14 proceeds to step S522.

[0304] On the other hand, if it is determined in step S511 that the inter-vehicle distance Dv is equal to or smaller than the threshold value Dvth (step S511: YES), the travel_ECU 14 proceeds to step S512.

[0305] In step S512, the traveling_ECU 14 checks whether the preceding vehicle speed Vp is equal to or lower than the set vehicle speed Vset of the host vehicle O.

[0306] Then, in step S512, when it is determined that the preceding vehicle speed Vp is greater than the set vehicle speed Vset (step S512: NO), the traveling_ECU 14 proceeds to step S522.

[0307] On the other hand, if it is determined in step S512 that the preceding vehicle speed Vp is equal to or lower than the set vehicle speed Vset (step S504: YES), the traveling_ECU 14 proceeds to step S513.

[0308] In step S513, the traveling_ECU 14 checks whether or not the host vehicle O and the preceding vehicle P are traveling in the same lane.

[0309] Then, in step S513, if it is determined that both vehicles are not traveling on the same lane (step S513: NO), the traveling_ECU 14 proceeds to step S515.

[0310] On the other hand, if it is determined in step S513 that both vehicles are traveling on the same lane (step S513: YES), the traveling_ECU 14 proceeds to step S514.

[0311] In step S514, the traveling_ECU 14 checks whether the traveling states of both the host vehicle O and the preceding vehicle P are constant speed traveling states.

[0312] Then, in step S514, if it is determined that the traveling state of both vehicles is a constant speed traveling state (step S514: YES), the traveling_ECU 14 exits the routine as it is.

[0313] On the other hand, when it is determined in step S514 that the traveling state of at least one of the vehicles is not a constant speed traveling state (step S514: NO), the traveling_ECU 14 proceeds to step S515.

[0314] In step S515, the traveling_ECU 14 checks whether the monitoring flag Fslc is set to "1." That is, the traveling_ECU 14 checks whether the preceding vehicle P is a target of synchronous lane change monitoring and whether the preceding vehicle registration cancellation condition for the preceding vehicle P (preceding vehicle L) is relaxed.

[0315] Then, in step S515, if it is determined that the monitoring flag Fslc is cleared to "0" (step S515: NO), the traveling_ECU 14 proceeds to step S522.

[0316] On the other hand, if it is determined in step S515 that the monitoring flag Fslc is set to "1" (step S515: YES), the traveling_ECU 14 proceeds to step S516.

[0317] In step S516, the driving_ECU 14 checks whether the driving state of the host vehicle O has transitioned to a lane change state before the preceding vehicle P (preceding vehicle L).

[0318] Then, in step S516, if it is determined that the driving state of the host vehicle O has not transitioned to a lane change state, or if it is determined that the driving state of the leading vehicle P has transitioned to a lane change state before the host vehicle O (step S516: NO), the driving_ECU 14 proceeds to step S519.

[0319] On the other hand, in step S516, when it is determined that the driving state of the host vehicle O has transitioned to the lane change state earlier than the preceding vehicle P (step S516: YES), the driving_ECU 14 proceeds to step S517.

[0320] In step S517, the traveling_ECU 14 checks whether the traveling state of the preceding vehicle P (preceding vehicle L) is maintained in a steady traveling state.

[0321] Then, in step S517, if it is determined that the traveling state of the preceding vehicle P has transitioned from the steady traveling state to another traveling state (step S517: NO), the traveling_ECU 14 proceeds to step S519.

[0322] On the other hand, in step S517, when it is determined that the traveling state of the preceding vehicle P is maintained as the steady traveling state (step S517: YES), the traveling_ECU 14 proceeds to step S518.

[0323] In step S518, the driving_ECU 14 checks whether or not a time T1 (for example, T1=5 seconds) has elapsed after the driving state of the host vehicle O transitioned to a lane change state.

[0324] Then, when it is determined in step S518 that the time T1 has elapsed since the travel state of the host vehicle O transitioned to the lane change state, the travel_ECU 14 proceeds to step S522. In other words, when the time T1 has elapsed since the host vehicle O transitioned to the lane change state, the travel_ECU 14 determines that even if the vehicle ahead P starts to change lanes, the lane change of the vehicle ahead P cannot be regarded as a synchronous lane change with the host vehicle O, and proceeds to step S522.

[0325] On the other hand, if it is determined in step S518 that the time T1 has not elapsed since the vehicle O's driving state transitioned to the lane change state, the driving_ECU 14 proceeds to step S519. In this way, when the monitoring flag Fslc is set to "1", the driving_ECU 14 relaxes the preceding vehicle registration cancellation condition, and monitors the possibility that the preceding vehicle P will change lanes synchronously with the vehicle O until the time T1 has elapsed, even if the vehicle O transitions to the lane change state.

[0326] When the process proceeds from step S516, step S517, or step S518 to step S519, the travel_ECU 14 checks whether the traveling state of the vehicle in front P (preceding vehicle L) has transitioned to a lane change state before the host vehicle O.

[0327] Then, in step S519, if it is determined that the driving state of the preceding vehicle P has not transitioned to a lane change state, or if it is determined that the driving state of the host vehicle O has transitioned to a lane change state before the preceding vehicle P (step S519: NO), the driving_ECU 14 exits the routine.

[0328] On the other hand, in step S519, when it is determined that the traveling state of the preceding vehicle P has transitioned to the lane change state earlier than the host vehicle O (step S519: YES), the traveling_ECU 14 proceeds to step S520.

[0329] In step S520, the traveling_ECU 14 checks whether the traveling state of the host vehicle O is maintained in a steady traveling state.

[0330] Then, in step S520, when it is determined that the running state of the host vehicle O has transitioned from the steady running state to another running state (step S520: NO), the running_ECU 14 exits the routine as is.

[0331] On the other hand, when it is determined in step S520 that the traveling state of the host vehicle O is maintained in the steady traveling state (step S520: YES), the traveling_ECU 14 proceeds to step S521.

[0332] In step S521, the traveling_ECU 14 checks whether or not a time T2 (for example, T1=2 [seconds]) has elapsed after the traveling state of the preceding vehicle P transitioned to a lane-changing state.

[0333] Then, in step S521, if it is determined that the time T2 has not elapsed since the driving state of the preceding vehicle P transitioned to the lane-changing state, the driving_ECU 14 exits the routine as is. In this way, when the monitoring flag Fslc is set to "1", the driving_ECU 14 relaxes the preceding vehicle registration cancellation condition, and monitors the possibility that the host vehicle O will change lanes synchronously with the preceding vehicle P until the time T2 has elapsed, even if the preceding vehicle P transitions to the lane-changing state.

[0334] On the other hand, if it is determined in step S521 that the time T2 has elapsed since the traveling state of the preceding vehicle P transitioned to the lane change state, the traveling_ECU 14 proceeds to step S522. In other words, if the time T2 has elapsed since the preceding vehicle P transitioned to the lane change state, the traveling_ECU 14 determines that even if the host vehicle O has started to change lanes, the lane change of the host vehicle O cannot be regarded as a synchronous lane change with the preceding vehicle P, and proceeds to step S522.

[0335] When the process proceeds from step S511, step S512, step S515, step S518, or step S521 to step S522, the travel_ECU 14 cancels the registration of the preceding vehicle P as the preceding vehicle L, and then exits the routine.

[0336] When the monitoring flag Fslc is set to "1" as a result of the preceding vehicle registration determination, the preceding vehicle registration condition and the preceding vehicle registration cancellation condition are relaxed. As a result, even when the host vehicle O changes lanes, the preceding vehicle P is registered as the preceding vehicle L under predetermined conditions. For example, as shown in Figs. 27 to 28, the preceding vehicle registration of the preceding vehicle P is maintained even when the traveling state of the host vehicle O transitions from a steady traveling state to a target lane traveling state via a lane change state.

[0337] On the other hand, when the monitoring flag Fslc is cleared to "0", when the driving state of the host vehicle O transitions to a lane change state, the preceding vehicle registration of the vehicle P ahead is easily cancelled.

[0338] Next, the following vehicle distance control for the host vehicle O will be described with reference to a flowchart of a following vehicle distance control routine shown in Fig. 26. This routine is repeatedly executed by the travel_ECU 14 at set time intervals.

[0339] When the routine starts, in step S601, the travel_ECU 14 checks whether or not a preceding vehicle L is present ahead of the host vehicle O. That is, the travel_ECU 14 checks whether or not a preceding vehicle P registered as a preceding vehicle L is present ahead of the host vehicle O.

[0340] Then, in step S601, if it is determined that a preceding vehicle L exists ahead of the host vehicle O (step S601: YES), the travel_ECU 14 proceeds to step S602.

[0341] When the process proceeds from step S601 to step S602, the traveling_ECU 14 executes the following traveling control for the preceding vehicle L, and then exits the routine.

[0342] On the other hand, in step S601, when it is determined that the preceding vehicle L does not exist ahead of the host vehicle O (step S601: NO), the travel_ECU 14 proceeds to step S603.

[0343] When the process proceeds from step S601 to step S603, the driving_ECU 14 checks whether the driving state of the host vehicle O is a lane change state.

[0344] Then, in step S603, when it is determined that the traveling state of the host vehicle O is a lane change state (step S603: YES), the traveling_ECU 14 proceeds to step S605.

[0345] On the other hand, when it is determined in step S603 that the traveling state of the host vehicle O is not a lane change state (step S603: NO), the traveling_ECU 14 proceeds to step S604.

[0346] In step S604, the driving_ECU 14 checks whether the driving state of the host vehicle O is the target lane driving state.

[0347] Then, in step S604, when it is determined that the traveling state of the host vehicle O is not the target lane traveling state (step S604: NO), the traveling_ECU 14 proceeds to step S606.

[0348] On the other hand, when it is determined in step S604 that the driving state of the host vehicle O is the target lane driving state (step S604: YES), the driving_ECU 14 proceeds to step S605.

[0349] When the process proceeds from step S603 or step S604 to step S605, the traveling_ECU 14 checks whether or not the host vehicle speed Vo is less than a set vehicle speed.

[0350] Then, in step S605, when it is determined that the host vehicle speed Vo is less than the set vehicle speed Vset (step S605: YES), the traveling_ECU 14 executes lane change acceleration control and then exits the routine.

[0351] On the other hand, when it is determined in step S605 that the host vehicle speed Vo is equal to or greater than the set vehicle speed Vset (step S605: NO), the traveling_ECU 14 proceeds to step S606.

[0352] When the process proceeds from step S604 or step S605 to step S606, the traveling_ECU 14 executes constant speed traveling control and then exits the routine.

[0353] According to this embodiment, the travel_ECU 14 classifies the travel state of the host vehicle O into one of a steady travel state, a lane change state, and a target lane travel state based on the lateral movement information of the host vehicle O and the relative position information between the host vehicle O and the lane markings. The travel_ECU 14 also extracts a vehicle traveling in front of the host vehicle O as a leading vehicle P based on the travel environment information, and classifies the travel state of the leading vehicle P into one of a steady travel state, a lane change state, and a target lane travel state based on the lateral movement information of the leading vehicle P and the relative position information between the leading vehicle P and the lane markings. This makes it possible to appropriately monitor the transition of the travel states of the host vehicle O and the leading vehicle P.

[0354] That is, the travel_ECU 14 classifies the travel state of the host vehicle O based on the lateral movement information of the host vehicle O and the relative position information between the host vehicle O and the lane markings. Similarly, the travel_ECU 14 classifies the travel state of the vehicle in front P based on the lateral movement information of the vehicle in front P and the relative position information between the vehicle in front P and the lane markings. This makes it possible to accurately classify the travel states of the host vehicle O and the vehicle in front P, including lane change scenes in which the lanes in which the host vehicle O and the vehicle in front P are traveling become unclear. Then, based on such a judgment criterion, the travel_ECU 14 classifies the travel states of the host vehicle O and the vehicle in front P into one of a steady travel state, a lane change state, and a target lane travel state. This makes it possible to appropriately monitor the transition of the travel states of the host vehicle O and the vehicle in front P from the start of lane change to the end of lane change.

[0355] Furthermore, by classifying the driving states of the vehicle O and the vehicle in front P into a steady driving state, a lane change state, and a target lane driving state, it is possible to easily determine whether the vehicle O and the vehicle in front P are changing lanes in sync within a specified time.

[0356] In addition, the travel_ECU 14 performs preceding vehicle monitoring to check whether the preceding vehicle P performs a synchronous lane change to the same target lane as the subject vehicle O, with a start condition that the preceding vehicle P registered as the preceding vehicle L and the subject vehicle O are steadily traveling in the same lane, and when preceding vehicle monitoring is being performed, the preceding vehicle registration condition is relaxed compared to when preceding vehicle monitoring is not being performed, and the preceding vehicle registration cancellation condition is relaxed as well. This makes it possible to suppress unnecessary acceleration and deceleration when changing lanes.

[0357] That is, when there is a possibility that the host vehicle O and the preceding vehicle P will perform synchronous lane changes to the same target lane, the travel_ECU 14 relaxes the preceding vehicle registration condition and the preceding vehicle registration cancellation condition for the preceding vehicle P. This makes it possible to prevent the preceding vehicle registration and preceding vehicle registration cancellation for the preceding vehicle P from switching between each other in a short period of time when changing lanes, and to suppress unnecessary acceleration and deceleration when changing lanes. In particular, it is possible to effectively suppress the execution of unnecessary lane-change acceleration control, and to suppress unnecessary acceleration and deceleration when changing lanes.

[0358] Here, when vehicle-in-front monitoring is being performed (monitoring flag Fslc is set to "1") and vehicle-in-front P is registered as a preceding vehicle L, the travel_ECU 14 suspends the cancellation of the registration of vehicle-in-front P as a preceding vehicle L for a set time when either vehicle O or vehicle-in-front P starts to change lanes, and maintains the registration of vehicle-in-front P as a preceding vehicle L when the other of vehicle O or vehicle-in-front P starts to change lanes to the same target lane within the set time. This makes it possible to preferably maintain the registration of vehicle-in-front P as a preceding vehicle L when vehicle O and vehicle-in-front P make synchronous lane changes.

[0359] In addition, when the vehicle in front is monitored (the monitoring flag Fslc is set to "1") and the vehicle in front P is not registered as the preceding vehicle L, if the vehicle in front P is already changing lanes to the same target lane when the vehicle in front starts to change lanes, the travel_ECU 14 registers the vehicle in front P as the preceding vehicle L. This allows the vehicle in front P to be quickly registered as the preceding vehicle L when the vehicle in front and the vehicle in front P perform synchronous lane changes, even if the vehicle in front is changing lanes.

[0360] In the above-described embodiment, the image recognition_ECU 13, the driving_ECU 14, the E / G_ECU 22, the t·M_ECU 23, the BK_ECU 24, the PS_ECU 25, etc. are configured with a well-known microcomputer equipped with a CPU, RAM, ROM, a non-volatile storage unit, etc., and with peripheral devices thereof, and the ROM stores programs to be executed by the CPU and fixed data such as data tables in advance. Note that all or part of the functions of the processor may be configured with a logic circuit or an analog circuit, and the processing of various programs may be realized by an electronic circuit such as an FPGA.

[0361] The invention described in the above embodiment is not limited to the embodiment, and various modifications can be made in the implementation stage without departing from the gist of the invention. Furthermore, the above embodiment includes inventions at various stages, and various inventions can be extracted by appropriate combinations of the disclosed constituent elements.

[0362] For example, if the problem described can be solved and the effect described can be obtained even if some of the constituent elements are deleted from all the constituent elements shown in the above form, the configuration from which these constituent elements are deleted can be extracted as an invention. [Explanation of symbols]

[0363] 1. Driving assistance devices 10 … Camera unit 11 … Stereo camera 11a ... Main camera 11b … Sub camera 13...Image Recognition_ECU 14 … Driving_ECU 20 … Locator unit 20a … GNSS sensor 20b … Road map DB 21lf ... Left front side sensor 21lr ... Left rear side sensor 21rf … Right front side sensor 21rr … Right rear side sensor 22 … E / G_ECU 23 … T / M_ECU 24 … BK_ECU 25 … PS_ECU 32 … Throttle actuator 33 ... Hydraulic control circuit 34 ... Brake actuator 35 ... Electric power steering motor O … Vehicle (own vehicle) P... Car in front

Claims

1. a preceding vehicle registration determination means for registering a preceding vehicle traveling ahead of the host vehicle as a preceding vehicle based on a preset preceding vehicle registration condition, and canceling the registration of the preceding vehicle as the preceding vehicle based on a preset preceding vehicle registration cancellation condition; a preceding vehicle monitoring means for monitoring the preceding vehicle as to whether or not the preceding vehicle performs a synchronous lane change to the same target lane as the subject vehicle, with a start condition being that the preceding vehicle registered as the preceding vehicle and the subject vehicle are steadily traveling in the same lane, The preceding vehicle registration determination means relaxes the preceding vehicle registration conditions and the preceding vehicle registration cancellation conditions when the preceding vehicle monitoring is being performed, compared to when the preceding vehicle monitoring is not being performed.

2. 2. A driving assistance device for a vehicle as described in claim 1, further comprising a following distance control means for selectively executing a following driving control for causing the host vehicle to follow the preceding vehicle when the preceding vehicle is registered in front of the host vehicle, a constant speed driving control for maintaining the host vehicle speed at a set vehicle speed and driving the host vehicle at a constant speed when the preceding vehicle is not registered in front of the host vehicle, and a lane change acceleration control for temporarily accelerating the host vehicle using a target acceleration obtained by correcting the target acceleration by the constant speed driving control to an increasing side when the registration of the preceding vehicle is canceled due to the host vehicle changing lanes.

3. The vehicle driving assistance device of claim 1, characterized in that when the preceding vehicle monitoring is being performed and the preceding vehicle is registered as the preceding vehicle, when either the host vehicle or the preceding vehicle starts to change lanes, the preceding vehicle registration determination means suspends the cancellation of the registration of the preceding vehicle as the preceding vehicle for a set time, and when the other of the host vehicle and the preceding vehicle starts to change lanes to the same target lane within the set time, maintains the registration of the preceding vehicle as the preceding vehicle.

4. The vehicle driving assistance device of claim 1, characterized in that when the preceding vehicle monitoring is being performed and the registration of the preceding vehicle as the preceding vehicle is cancelled, when the host vehicle starts to change lanes, if the preceding vehicle is already changing lanes to the same target lane, the preceding vehicle registration determination means registers the preceding vehicle as the preceding vehicle.

5. 2. The vehicle driving support device according to claim 1, wherein the vehicle-in-front monitoring means cancels the vehicle-in-front monitoring when the host vehicle and the vehicle in front are traveling in the same target lane.

6. The vehicle driving assistance device of claim 5, characterized in that the preceding vehicle monitoring means cancels the preceding vehicle monitoring when a preset cancellation condition is met, even if the host vehicle and the preceding vehicle are not traveling in the same target lane.

7. A processor is provided. The processor, a preceding vehicle registration determination is performed to register a preceding vehicle traveling ahead of the vehicle as a preceding vehicle based on a preset preceding vehicle registration condition, and to cancel the registration of the preceding vehicle as the preceding vehicle based on a preset preceding vehicle registration cancellation condition; A vehicle ahead monitoring is performed to check whether the vehicle ahead, which is registered as the preceding vehicle, and the vehicle itself are steadily traveling in the same lane, to see if the vehicle ahead performs a synchronous lane change to the same target lane as the vehicle ahead, using a condition that the vehicle ahead is registered as the preceding vehicle and the vehicle itself as being steadily traveling in the same lane. A vehicle driving assistance device characterized in that, when the preceding vehicle monitoring is being performed, the preceding vehicle registration conditions are relaxed and the preceding vehicle registration cancellation conditions are relaxed compared to when the preceding vehicle monitoring is not being performed.

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