Adaptive Cruise Control Device

Abstract

To provide a following-travelling control device that can appropriately suppress acceleration of an own vehicle having performed lane change, as needed.SOLUTION: When lane change of vehicle 1 is performed (S31:YES), it is determined whether the lane change is lane change from a passing lane to a travelling lane (S32). When the lane change is not the lane change from the passing lane to the travelling lane (S32:NO) and when the lane change is lane change from the travelling lane to the passing lane, acceleration of the vehicle is not suppressed. When the lane change is the lane change from the passing lane to the travelling lane (S32:YES), the acceleration of the vehicle is suppressed (S33).SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a following cruise control device that causes a host vehicle to follow a preceding vehicle. [Background technology]

[0002] Recently, vehicles have been equipped with a function that allows the vehicle to travel by following the vehicle ahead, known as an adaptive cruise control (ACC) function.

[0003] During following driving using the ACC function, a target inter-vehicle distance between the host vehicle and the preceding vehicle is set based on the vehicle speed of the host vehicle, and the target inter-vehicle distance is subtracted from the actual inter-vehicle distance to obtain an inter-vehicle distance deviation (= inter-vehicle distance - target inter-vehicle distance). The relative speed between the host vehicle and the preceding vehicle is also obtained. Then, a target acceleration is set according to the inter-vehicle distance deviation and the relative speed, and the output of the host vehicle's engine or the braking force of the friction brake is controlled so that the host vehicle accelerates or decelerates at the target acceleration.

[0004] When the host vehicle changes lanes during following travel, it is determined whether or not a preceding vehicle exists in the new lane. If a preceding vehicle exists, a target acceleration of the host vehicle is set according to the deviation in the inter-vehicle distance and the relative speed between the preceding vehicle and the host vehicle, and control is performed to accelerate or decelerate the host vehicle at the target acceleration. On the other hand, if no preceding vehicle exists, control is performed to accelerate or decelerate the host vehicle so that the host vehicle travels at a constant speed at the set vehicle speed.

[0005] However, since the purpose of the lane change is unclear in the control, the control to accelerate the vehicle after the lane change may not be the control desired by the driver. Therefore, it has been proposed to prohibit the acceleration of the vehicle when the vehicle changes lanes until a predetermined time has elapsed after the lane change (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2000-296724 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, if acceleration of the host vehicle is prohibited every time the host vehicle changes lanes, the user may feel uncomfortable.

[0008] An object of the present invention is to provide an adaptive cruise control device that can appropriately suppress acceleration of the host vehicle after changing lanes as necessary. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, a following driving control device according to one aspect of the present invention is a following driving control device that causes the host vehicle to follow a preceding vehicle by accelerating and decelerating the host vehicle so that the actual inter-vehicle distance between the host vehicle and a preceding vehicle ahead of it is maintained at a target inter-vehicle distance, and includes an external world recognition means for recognizing the surroundings of the host vehicle, an acceleration / deceleration control means for controlling the acceleration / deceleration of the host vehicle, a lane change detection means for detecting a lane change of the host vehicle, and an acceleration suppression means for suppressing acceleration by the acceleration / deceleration control means when a lane change is detected by the lane change detection means and a preceding vehicle is recognized by the external world recognition means in the lane to which the lane is changed, and the acceleration suppression means suppresses acceleration to a greater extent the closer the host vehicle is to the preceding vehicle.

[0010] According to this configuration, when the vehicle ahead is traveling in the lane after the vehicle has changed lanes, the acceleration of the vehicle is suppressed. Moreover, the closer the vehicle is to the vehicle ahead, that is, the shorter the inter-vehicle distance between the vehicle ahead and the vehicle ahead, or the greater the relative speed of the vehicle ahead in the direction in which the vehicle approaches the vehicle ahead, the greater the suppression of the acceleration of the vehicle ahead. Therefore, when the vehicle ahead changes lanes, the vehicle ahead can be prevented from approaching the vehicle ahead, and the user can be prevented from feeling uneasy.

[0011] Conversely, the longer the inter-vehicle distance between the vehicle and the preceding vehicle, or the slower the relative speed of the vehicle approaching the preceding vehicle (the faster the relative speed of the vehicle moving away from the preceding vehicle), the more relaxed the suppression of the acceleration of the vehicle. Therefore, the vehicle can be made to follow the preceding vehicle traveling in the new lane, and the user can be prevented from feeling that the vehicle is being left behind by the preceding vehicle. In addition, the user can be prevented from feeling uncomfortable due to the large suppression of the acceleration of the vehicle every time the lane is changed.

[0012] Therefore, the acceleration of the host vehicle after changing lanes can be appropriately suppressed as necessary.

[0013] The acceleration suppression means may suppress acceleration for a predetermined suppression time. In this case, it is preferable that the suppression time is set to a longer time as the speed of the host vehicle increases.

[0014] This makes it possible to prevent the user from feeling uneasy when the host vehicle approaches the preceding vehicle at a high speed.

[0015] A following driving control device according to another aspect of the present invention is a following driving control device that causes the host vehicle to follow a preceding vehicle by accelerating and decelerating the host vehicle so that the actual inter-vehicle distance between the host vehicle and a preceding vehicle ahead of it is maintained at a target inter-vehicle distance, and includes an external world recognition means for recognizing the surroundings of the host vehicle, an acceleration / deceleration control means for controlling the acceleration / deceleration of the host vehicle, a lane change detection means for detecting a lane change of the host vehicle, an acceleration suppression means for suppressing acceleration by the acceleration / deceleration control means for a predetermined time in response to a lane change request, and an acceleration suppression release means for releasing the suppression of acceleration by the acceleration / deceleration control means before the predetermined time has elapsed if the external world recognition means does not recognize a preceding vehicle in the lane to which the lane is changed after a lane change is detected by the lane change detection means.

[0016] In cases where the user cannot recognize whether there is a preceding vehicle in the lane to which the vehicle is to be changed because a preceding vehicle in the current lane is in the way, or in cases where there is a preceding vehicle in the lane to which the vehicle is to be changed that is slower than the vehicle's own vehicle and the vehicle accelerates after changing lanes, the vehicle may approach the preceding vehicle, which may cause the user to feel uneasy. As a countermeasure to this, the acceleration of the vehicle is suppressed when a lane change request is made.

[0017] If a preceding vehicle is detected in the new lane after the lane change, the suppression of acceleration of the vehicle continues until a predetermined time has elapsed. This makes it possible to suppress the vehicle from approaching the preceding vehicle and prevent the user from feeling uneasy.

[0018] On the other hand, if a preceding vehicle is not recognized in the new lane after the lane change, the suppression of acceleration of the vehicle is released even before the predetermined time has elapsed. Therefore, the vehicle can be accelerated without waiting for the predetermined time. This makes it possible to suppress the discomfort felt by the user due to the suppression of acceleration of the vehicle for a predetermined time every time the vehicle changes lanes.

[0019] Therefore, the acceleration of the host vehicle after changing lanes can be appropriately suppressed as necessary.

[0020] A following driving control device according to yet another aspect of the present invention is a following driving control device that causes the host vehicle to follow a preceding vehicle by accelerating and decelerating the host vehicle so that the actual inter-vehicle distance between the host vehicle and the preceding vehicle ahead of it is maintained at a target inter-vehicle distance, and includes an acceleration / deceleration control means for controlling the acceleration / deceleration of the host vehicle, a lane change detection means for detecting lane changes of the host vehicle, and an acceleration suppression means for not suppressing acceleration by the acceleration / deceleration control means when the lane change detection means detects a lane change from the driving lane to the overtaking lane, and for suppressing acceleration by the acceleration / deceleration control means when the lane change detection means detects a lane change from the overtaking lane to the driving lane.

[0021] According to this configuration, when the vehicle changes lanes, if the lane change is from a driving lane to an overtaking lane, the acceleration of the vehicle is not suppressed. After changing lanes from a driving lane to an overtaking lane, the vehicle often accelerates. In this case, it is possible to suppress the discomfort felt by the user due to the suppression of the acceleration of the vehicle.

[0022] On the other hand, when the lane change of the host vehicle is from an overtaking lane to a driving lane, there is often a vehicle ahead of the host vehicle that is moving slower than the host vehicle in the driving lane to which the host vehicle is to be changed. In this case, the acceleration of the host vehicle is suppressed. This makes it possible to suppress the host vehicle from approaching the vehicle ahead, and to prevent the user from feeling uneasy.

[0023] Therefore, the acceleration of the host vehicle after changing lanes can be appropriately suppressed as necessary. Effect of the Invention

[0024] According to the present invention, the acceleration of the host vehicle after changing lanes can be appropriately suppressed as necessary. [Brief description of the drawings]

[0025] [Figure 1] 1 is a block diagram showing a configuration of a main part of a vehicle equipped with a follow-up cruise control device according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a diagram conceptually showing the contents of a target acceleration map. [Diagram 3] FIG. 2 is a diagram illustrating a lane change of a vehicle; [Figure 4] 10 is a flowchart showing a flow of an acceleration suppression process executed when changing lanes. [Diagram 5] 10 is a flowchart showing a flow of an acceleration suppression process according to a second embodiment. [Figure 6] 13 is a flowchart showing a flow of an acceleration suppression process according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0027] <Vehicle Electrical Configuration> FIG. 1 is a block diagram showing the configuration of a main part of a vehicle 1 equipped with a following cruise control device according to one embodiment of the present invention.

[0028] The vehicle 1 is an automobile using an engine 2 as a drive source. The power of the engine 2 is transmitted to left and right drive wheels via a transmission. The transmission may be a continuously variable transmission (CVT), a stepped automatic transmission (AT), or a manual transmission (MT).

[0029] The engine 2 is, for example, a gasoline engine, and is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) for injecting fuel into the intake air, and a spark plug for generating an electric discharge in the combustion chamber. The engine 2 is also provided with a starter for starting the engine.

[0030] An accelerator pedal operated to accelerate or decelerate the vehicle 1, and a brake pedal operated to brake the vehicle 1 are provided under the driver's seat in the cabin of the vehicle 1. The accelerator pedal and the brake pedal are located at positions convenient for the driver sitting in the driver's seat to step on them with his / her right foot.

[0031] The vehicle 1 is also equipped with a hydraulic brake. The hydraulic brake includes a brake booster, a master cylinder, and a brake actuator 3. When the brake pedal is depressed, the depression force input to the brake pedal is transmitted to the brake booster. The depression force transmitted to the brake booster is amplified (doubled) by the negative pressure of the brake booster, and is input from the brake booster to the master cylinder. The master cylinder generates hydraulic pressure according to the force input from the brake booster. The hydraulic pressure generated by the master cylinder is transmitted to the brake actuator 3. Then, by the function of the brake actuator 3, hydraulic pressure is distributed to the wheel cylinders of the brakes provided on each wheel, and the hydraulic pressure applies braking force from each brake to the wheels including the drive wheels.

[0032] The vehicle 1 is equipped with an ECU (Electronic Control Unit) 4 including a microcontroller (microcontroller unit). The microcontroller includes, for example, a CPU, a non-volatile memory such as a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory). Although only one ECU 4 is shown in FIG. 1, the vehicle 1 is equipped with multiple ECUs having the same configuration as the ECU 4 to control each part. The multiple ECUs including the ECU 4 are connected to enable two-way communication using a CAN (Controller Area Network) communication protocol.

[0033] An engine control logic and a brake control logic are built into the ECU 4. The engine control logic controls an electronic throttle valve, an injector, a spark plug, and the like to adjust the start, stop, output, and the like of the engine 2 based on detection signals input from various sensors connected to the ECU 4 and information input from other ECUs. The brake control logic controls a brake actuator 3 and the like to adjust the vehicle speed, attitude, and the like of the vehicle 1 based on detection signals input from various sensors and information input from other ECUs.

[0034] The various sensors include, for example, a vehicle speed sensor 5 and an external environment recognition sensor 6.

[0035] The vehicle speed sensor 5 includes, for example, a rotor made of a magnetic material that rotates as the vehicle 1 travels, and an electromagnetic pickup that is provided in a non-contact manner with the rotor, and outputs a pulse signal from the electromagnetic pickup every time the rotor rotates a certain angle. The frequency of this pulse signal corresponds to the actual vehicle speed of the vehicle 1. The ECU 4 obtains the frequency of the signal input from the vehicle speed sensor 5, and converts the frequency into vehicle speed.

[0036] The external environment recognition sensor 6 is, for example, a stereo camera. The stereo camera is a camera capable of continuously capturing still images at a predetermined frame rate, and is capable of detecting the distance to the position of a target in the captured image from parallax information. The stereo camera is installed, for example, on a rearview mirror at the front center of the vehicle interior so as to capture an image in front of the vehicle 1 at a wide angle. In addition to the stereo camera, the vehicle 1 may be provided with a radar as the external environment recognition sensor 6. The radar is installed in the front of the vehicle 1, and is a sensor for detecting the situation in a predetermined search range in front of the vehicle 1. The radar irradiates a radar wave (millimeter wave, laser) into the search range, receives a reflected wave from an object present in the search range, and outputs a detection signal according to the reflected wave.

[0037] Vehicle 1 is equipped with an adaptive cruise control (ACC) function as a driving assistance function.

[0038] The ACC function is a following driving function that causes the vehicle 1 to follow another vehicle ahead of it. For example, the steering wheel is provided with an operation switch 7 related to the ACC function. The operation switch 7 includes an ACC main switch that turns the ACC function on / off, a set switch that sets the current vehicle speed of the vehicle 1 as a set vehicle speed, a set vehicle distance changeover switch that changes the distance between the vehicle 1 and the preceding vehicle, a cancel switch that cancels the operation of the ACC function, and a resume switch that reactivates the ACC function at the previous set vehicle speed.

[0039] When the ACC main switch is pressed, the ACC function is activated. Then, when the set switch is pressed, the current vehicle speed of the vehicle 1 is set to the set vehicle speed. The set vehicle speed can be changed by pressing the resume switch or the set switch. That is, by pressing the resume switch, the set vehicle speed can be increased, and by pressing the set switch, the set vehicle speed can be decreased. In addition, by pressing the set vehicle distance changeover switch, it is possible to switch between setting the vehicle distance longer, shorter, or somewhere in between.

[0040] When the set vehicle speed is set, the ECU 4 starts ACC control (adaptive driving control) for making the vehicle 1 follow the vehicle ahead of it. In the ACC control, depending on whether there is a vehicle ahead of it, the vehicle 1 automatically switches between following the vehicle ahead of it with the set vehicle speed set by a switch operation as the upper limit vehicle speed, and constant speed driving at the set vehicle speed. During following driving, the vehicle 1 is accelerated or decelerated so that the distance between the vehicle 1 and the vehicle ahead of it is maintained at a target distance.

[0041] Specifically, a target inter-vehicle distance between vehicle 1 and a preceding vehicle is set based on the vehicle speed of vehicle 1, and an inter-vehicle distance deviation between the target inter-vehicle distance and the actual inter-vehicle distance (=actual inter-vehicle distance-target inter-vehicle distance) is calculated. Also, a relative speed between vehicle 1 and the preceding vehicle is calculated. Then, a target acceleration of vehicle 1 is set according to the inter-vehicle distance deviation and the relative speed. A non-volatile memory built into the microcomputer of ECU 4 stores the characteristics (relationship) of the target acceleration with respect to the inter-vehicle distance deviation and the relative speed in the form of a map as a target acceleration map. This target acceleration map is conceptually shown in FIG. 2, and is created so that the smaller the inter-vehicle distance deviation, the larger the target acceleration is set in the negative direction (deceleration direction). When the target acceleration is set, the engine output or the braking force of the brakes is controlled so that vehicle 1 accelerates or decelerates at the target acceleration.

[0042] <Acceleration suppression processing> Fig. 3 is a diagram illustrating lane changing of the vehicle 1. Fig. 4 is a flowchart showing the flow of the acceleration suppression process executed when changing lanes.

[0043] While the vehicle 1 is traveling under the ACC control, the ECU 4 executes an acceleration suppression process at a predetermined cycle to suppress acceleration when the vehicle 1 changes lanes.

[0044] In the acceleration suppression process, first, it is determined whether or not the vehicle 1 has changed lanes (step S11). For example, it is determined whether or not the vehicle 1 has crossed a lane boundary line (vehicle lane boundary line) between the driving lane and the passing lane from an image captured by a stereo camera, which is the external environment recognition sensor 6, as shown in Fig. 3, and it can be determined that the vehicle 1 has changed lanes because the vehicle 1 has crossed the lane boundary line.

[0045] If the vehicle 1 is not changing lanes (NO in step S11), the acceleration suppression process is ended.

[0046] When the vehicle 1 changes lanes (YES in step S11), the presence of a preceding vehicle traveling in the lane to which the lane is to be changed is confirmed from an image captured by the stereo camera, which is the external environment recognition sensor 6 (step S12).

[0047] If a preceding vehicle traveling in the lane to which the lane is to be changed is not recognized (NO in step S12), the acceleration suppression process is ended.

[0048] When a preceding vehicle is present in the lane to which the lane is to be changed and the preceding vehicle is recognized (YES in step S12), the acceleration of the vehicle 1 is suppressed (step S13). At this time, the distance between the vehicle 1 and the preceding vehicle is acquired from an image captured by the stereo camera, and the acceleration of the vehicle 1 is suppressed to a degree according to the distance between the vehicle 1 and the preceding vehicle. Specifically, the shorter the distance between the vehicle 1 and the preceding vehicle, the more the acceleration of the vehicle 1 is suppressed.

[0049] In addition, suppressing the acceleration of vehicle 1 means keeping the acceleration of vehicle 1 lower than the target acceleration set in accordance with the target acceleration map shown in Figure 2, and includes prohibiting the acceleration of vehicle 1, i.e., limiting the acceleration of vehicle 1 to 0 or less.

[0050] After suppression of acceleration of the vehicle 1 is started, it is determined whether a predetermined suppression time has elapsed since the start of the suppression (step S14). The suppression time may be a fixed time, but may be set according to the vehicle speed at the time of lane change of the vehicle 1, for example. In this case, it is preferable to set the suppression time to a longer time as the vehicle speed is higher.

[0051] When the suppression time has elapsed since the start of suppression of acceleration of the vehicle 1 (YES in step S14), the suppression of acceleration is released (step S15), and the acceleration suppression process is terminated.

[0052] <Action and effect> As described above, when the vehicle 1 has changed lanes and a preceding vehicle is traveling in the lane ahead, the acceleration of the vehicle 1 is suppressed. Moreover, the shorter the distance between the vehicle 1 and the preceding vehicle, the more the acceleration of the vehicle 1 is suppressed. Therefore, when the vehicle 1 changes lanes, the vehicle 1 can be prevented from approaching the preceding vehicle, and a sense of unease can be prevented from being given to the user.

[0053] Conversely, the longer the distance between the vehicle 1 and the preceding vehicle, the less the suppression of the acceleration of the vehicle 1 is. Therefore, the vehicle 1 can be made to follow the preceding vehicle traveling in the lane to which the vehicle 1 is to be changed, and the user can be prevented from feeling that the vehicle 1 is being left behind by the preceding vehicle. In addition, the user can be prevented from feeling uncomfortable due to the large suppression of the acceleration of the vehicle 1 every time the vehicle changes lanes.

[0054] Therefore, the acceleration of the vehicle 1 after changing lanes can be appropriately suppressed as necessary.

[0055] Suppression of acceleration of the vehicle 1 continues until a predetermined suppression time has elapsed from the start of the suppression. The suppression time is set to a longer time as the speed of the vehicle 1 increases, thereby suppressing the sense of anxiety felt by the user due to the vehicle 1 approaching a preceding vehicle at a high speed.

[0056] <Second embodiment> FIG. 5 is a flowchart showing a flow of the acceleration suppression process according to the second embodiment.

[0057] Instead of the acceleration suppression processing shown in FIG. 4, the acceleration suppression processing shown in FIG. 5 may be executed.

[0058] 5, first, it is determined whether or not a lane change of the vehicle 1 has been requested (step S21). For example, it can be determined that a lane change has been requested based on the operation of the turn signal of the vehicle 1.

[0059] If a lane change is not requested (NO in step S21), the acceleration suppression process is terminated. If a lane change is requested (YES in step S21), the acceleration of the vehicle 1 is suppressed (step S22). At this time, the acceleration of the vehicle 1 may be limited to a certain value or less, or similarly to the case of the acceleration suppression process shown in FIG. 4, the shorter the inter-vehicle distance between the vehicle 1 and the preceding vehicle, the more the acceleration of the vehicle 1 may be suppressed.

[0060] After the suppression of acceleration of the vehicle 1 is started, it is determined whether a predetermined time has elapsed since the start of the suppression (step S23). The predetermined time may be a fixed time, or may be set to a longer time as the vehicle speed of the vehicle 1 when changing lanes is higher.

[0061] When a predetermined time has elapsed since the start of suppression of acceleration of the vehicle 1 (YES in step S23), the suppression of acceleration is released (step S24), and the acceleration suppression process is terminated.

[0062] It is determined whether or not the vehicle 1 has changed lanes before the predetermined time has elapsed (step S25).

[0063] If the vehicle 1 has not changed lanes (NO in step S25), it is determined again whether or not a predetermined time has elapsed (step S23).

[0064] When the vehicle 1 changes lanes (YES in step S25), the presence of a preceding vehicle traveling in the lane to which the lane is to be changed is confirmed from an image captured by the stereo camera serving as the external environment recognition sensor 6 (step S26).

[0065] If a preceding vehicle exists in the lane to which the lane is to be changed and the preceding vehicle is recognized (YES in step S26), it is determined again whether or not a predetermined time has elapsed (step S23).

[0066] On the other hand, if a preceding vehicle traveling in the lane to which the lane is to be changed is not recognized (NO in step S26), the suppression of acceleration of the vehicle 1 is released (step S24), and the acceleration suppression process is terminated.

[0067] <Action and effect> In this acceleration suppression process, the acceleration of the vehicle 1 is suppressed in response to a request to change lanes.

[0068] Then, if a preceding vehicle is recognized in the lane to which the vehicle has changed lanes after the lane change, the suppression of acceleration of the vehicle 1 continues until a predetermined time has elapsed. This makes it possible to suppress the vehicle 1 from approaching the preceding vehicle, and to prevent the user from feeling uneasy.

[0069] On the other hand, if a preceding vehicle is not recognized in the lane to which the lane is changed after the lane change, the suppression of acceleration of the vehicle 1 is released even before the predetermined time has elapsed. Therefore, the vehicle 1 can be accelerated without waiting for the predetermined time. This makes it possible to suppress the discomfort felt by the user due to the acceleration of the vehicle 1 being suppressed for the predetermined time every time the lane is changed.

[0070] Therefore, the acceleration of the vehicle 1 after changing lanes can be appropriately suppressed as necessary.

[0071] <Third embodiment> FIG. 6 is a flowchart showing a flow of the acceleration suppression process according to the third embodiment.

[0072] Instead of the acceleration suppression processing shown in FIG. 4, the acceleration suppression processing shown in FIG. 6 may be executed.

[0073] In the acceleration suppression process shown in FIG. 6, first, it is determined whether or not the vehicle 1 has changed lanes (step S31).

[0074] If the vehicle 1 is not changing lanes (NO in step S31), the acceleration suppression process is ended.

[0075] When the vehicle 1 changes lanes (YES in step S31), it is determined from an image captured by the stereo camera, which is the external environment recognition sensor 6, whether the lane change is from the passing lane OL to the driving lane DL (step S32).

[0076] If the lane change is not from the overtaking lane OL to the driving lane DL (NO in step S32), that is, if the lane change is from the driving lane DL to the overtaking lane OL, the acceleration suppression process is ended.

[0077] If the lane change is from the overtaking lane OL to the driving lane DL (YES in step S32), the acceleration of the vehicle 1 is suppressed (step S33). At this time, the acceleration of the vehicle 1 may be limited to a certain value or less, or, similarly to the case of the acceleration suppression process shown in FIG. 4, the shorter the inter-vehicle distance between the vehicle 1 and the preceding vehicle, the more the acceleration of the vehicle 1 may be suppressed.

[0078] After the suppression of acceleration of the vehicle 1 starts, it is determined whether a predetermined suppression time has elapsed since the suppression start (step S34). The suppression time may be a fixed time, or may be set to a longer time as the vehicle speed of the vehicle 1 during the lane change is higher.

[0079] When the suppression time has elapsed since the start of suppression of acceleration of the vehicle 1 (YES in step S34), the suppression of acceleration is released (step S35), and the acceleration suppression process is terminated.

[0080] <Action and effect> In this acceleration suppression process, when the vehicle 1 changes lanes, if the lane change is from the driving lane DL to the overtaking lane OL, the acceleration of the vehicle 1 is not suppressed. After changing lanes from the driving lane DL to the overtaking lane OL, the vehicle 1 often accelerates. In this case, it is possible to suppress the discomfort felt by the user due to the suppression of the acceleration of the vehicle 1.

[0081] On the other hand, when the lane change of the vehicle 1 is from the overtaking lane OL to the driving lane DL, there is often a preceding vehicle in the driving lane DL that is moving slower than the vehicle 1. In this case, the acceleration of the vehicle 1 is suppressed. This makes it possible to suppress the vehicle 1 from approaching the preceding vehicle, and to prevent the user from feeling uneasy.

[0082] Therefore, the acceleration of the vehicle 1 after changing lanes can be appropriately suppressed as necessary.

[0083] <Modification> Although several embodiments of the present invention have been described above, the present invention can be embodied in other forms.

[0084] For example, in the above-described embodiment, when the acceleration of the vehicle 1 is suppressed, the vehicle distance between the vehicle 1 and the preceding vehicle is acquired, and the shorter the vehicle distance between the vehicle 1 and the preceding vehicle, the more the acceleration of the vehicle 1 is suppressed. However, without being limited to this, the relative speed between the vehicle 1 and the preceding vehicle may be acquired, and the greater the relative speed in the direction in which the vehicle 1 approaches the preceding vehicle, the more the acceleration of the vehicle 1 is suppressed.

[0085] In addition, in the above-described embodiment, the ECU 4 is described as incorporating engine control logic and brake control logic, but an engine ECU that controls the engine 2 and a brake ECU that controls the brake actuator 3 may be provided separately, and the functions of the ECU 4 may be realized by cooperation between the engine ECU and the brake ECU.

[0086] In addition, various design modifications can be made to the above-described configuration within the scope of the claims. [Explanation of symbols]

[0087] 1: Vehicle (own vehicle) 2: Engine 4: ECU (adaptive driving control device, acceleration / deceleration control means, lane change detection means, acceleration suppression means) 6: External recognition sensor (external recognition means) DL: Traffic lane OL: Passing lane

Claims

1. A follow-up running control device that causes a host vehicle to run following a preceding vehicle by accelerating or decelerating the host vehicle so that an actual inter-vehicle distance between the host vehicle and a preceding vehicle ahead of the host vehicle is maintained at a target inter-vehicle distance, an acceleration / deceleration control means for controlling acceleration / deceleration of the host vehicle; lane change detection means for detecting a lane change of the host vehicle; an acceleration suppression means for not suppressing acceleration by the acceleration / deceleration control means when a lane change from a driving lane to an overtaking lane is detected by the lane change detection means, and for suppressing acceleration by the acceleration / deceleration control means when a lane change from the overtaking lane to the driving lane is detected by the lane change detection means, The acceleration suppression means sets a suppression time to a longer time as the speed of the host vehicle increases, and releases the suppression of acceleration when the suppression time has elapsed since the start of the suppression of acceleration.

2. 2. The following cruise control device according to claim 1, wherein the acceleration suppression means, when suppressing acceleration, suppresses acceleration to a greater extent as the host vehicle and the preceding vehicle become closer to each other.

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