Vehicle control device

Abstract

To provide a vehicle control device which can achieve travel control to enable a driver to feel safe and comfortable in a status in which interruption of other vehicle in front of an own vehicle is detected during operation of adaptive cruise control (ACC).SOLUTION: A vehicle control device 1 includes an adaptive cruise control (ACC) controller 30 for performing constant-speed traveling at set vehicle speed, or follow-up traveling following a preceding vehicle while keeping a set inter-vehicle time. The ACC controller 30 switches a set inter-vehicle time to a set inter-vehicle time shorter than the set inter-vehicle time, in a case in which an actual inter-vehicle time for other vehicle is equal to or less than a set inter-vehicle time for the preceding vehicle, when interruption of other vehicle in front of an own vehicle is detected.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a control device for a vehicle.

Background Art

[0002] For example, as one of the functions for assisting the driver of a vehicle such as an automobile, Adaptive Cruise Control (ACC) is known. ACC assists the driver's operations of the accelerator and brake by performing constant-speed driving at a set vehicle speed or following driving while maintaining a set inter-vehicle time to follow a preceding vehicle. The inter-vehicle time is a value obtained by dividing the inter-vehicle distance from the preceding vehicle by the speed of the host vehicle, and indicates the time until the host vehicle reaches the current position of the preceding vehicle.

[0003] As a prior art related to ACC, for example, in Patent Document 1, during the operation of ACC, a warning situation in which a target vehicle may cut in between the host vehicle and the preceding vehicle is detected, and a driving control device is disclosed that changes the inter-vehicle distance from the preceding vehicle. In this driving control device, in a warning situation, by shortening the inter-vehicle distance to make it difficult for the target vehicle to cut in, or conversely, by extending the inter-vehicle distance to be prepared in advance so that it may be cut in by the target vehicle, the safety of ACC is improved. The mode of change of whether to shorten or extend the inter-vehicle distance can be selected in advance according to the driver's personality (preference).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, regarding the above prior art, it does not disclose what to do with the pre-changed inter-vehicle distance when, during the operation of ACC, a warning situation is detected, the inter-vehicle distance from the preceding vehicle is shortened or extended, and then the target vehicle actually cuts in between the host vehicle and the preceding vehicle. If, with the inter-vehicle distance from the preceding vehicle extended, the target vehicle cuts in front of the host vehicle and the target vehicle (the cutting-in vehicle) becomes the new preceding vehicle, applying a slightly stronger brake to maintain the inter-vehicle distance from the target vehicle may make the driver uncomfortable. During the operation of ACC, it is desired to realize a driving control that allows the driver of the host vehicle to feel safe and comfortable even after actually detecting an intrusion into the front of the host vehicle. The above prior art had room for improvement in terms of improving the driver's comfort.

[0006] The present invention has been made paying attention to the above points, and an object thereof is to provide a vehicle control device capable of realizing a driving control that allows a driver to feel safe and comfortable in a situation where an intrusion of another vehicle into the front of the host vehicle is detected during the operation of ACC.

Means for Solving the Problems

[0007] To achieve the above object, one aspect of the present invention provides a vehicle control device including: an adaptive cruise control means for performing a constant-speed driving at a set vehicle speed or a following driving for following a preceding vehicle while maintaining a set inter-vehicle time; and an intrusion detection means for detecting an intrusion of another vehicle into the front of the host vehicle. The adaptive cruise control means in this vehicle control device is configured to switch the set inter-vehicle time to a shorter set inter-vehicle time when the actual inter-vehicle time from the other vehicle is equal to or less than the set inter-vehicle time from the preceding vehicle when the intrusion of the other vehicle is detected by the intrusion detection means.

Effects of the Invention

[0008] According to the vehicle control device of the present invention, in a situation where an intrusion of another vehicle into the front of the host vehicle is detected during the operation of ACC, by shortening the set inter-vehicle time with the preceding vehicle, a large deceleration of the host vehicle can be suppressed. Therefore, it becomes possible to realize a driving control that allows the driver of the host vehicle to feel safe and comfortable.

Brief Description of the Drawings

[0009]

Figure 1

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Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration example of a vehicle control device 1 according to an embodiment of the present invention. The control device 1 according to the present embodiment is mounted on a vehicle such as an automobile, for example, and has an ACC (Adaptive Cruise Control) function for assisting the driver of the vehicle. As shown in FIG. 1 as its functional blocks, the control device 1 includes a surrounding situation detection unit 10, a vehicle state detection unit 20, an ACC controller 30, a vehicle control unit 40, and a display unit 50.

[0011] The surrounding situation detection unit 10 collects information on other vehicles, obstacles, road conditions, etc. located around the host vehicle and transmits it to the ACC controller 30. The vehicle state detection unit 20 detects the current driving state of the host vehicle and transmits it to the ACC controller 30. The ACC controller 30 generates a driving control command by the ACC based on each information from the surrounding situation detection unit 10 and the vehicle state detection unit 20. The driving control command generated by the ACC controller 30 is transmitted to the vehicle control unit 40 and the display unit 50, respectively.

[0012] The vehicle control unit 40 controls the driving state of the host vehicle according to the driving control command from the ACC controller 30. The display unit 50 displays information on the driving state of the host vehicle corresponding to the driving control command from the ACC controller 30 to the driver. Hereinafter, specific configuration examples of each part of the control device 1 as described above will be described in detail.

[0013] The surrounding situation detection unit 10 has, for example, a millimeter-wave radar 11, a camera sensor 12, and a Blind Spot Monitor (BSM) 13. The millimeter-wave radar 11 is attached to the front grille or the like at the front of the vehicle. The millimeter-wave radar 11 detects an object located in front of the vehicle (for example, a preceding vehicle or an obstacle), and collects information such as the distance and speed from the host vehicle to the object.

[0014] The camera sensor 12 is a monocular camera or a stereo camera installed on the front, rear, left, and right of the vehicle. By processing the image captured by the camera sensor 12, it becomes possible to collect information about objects around the vehicle (for example, vehicles, white lines, traffic signs, pedestrians, obstacles, etc.).

[0015] The BSM 13 uses a quasi-millimeter-wave radar attached to the left and right rear ends of the rear bumper or the like to detect an object diagonally behind the vehicle that is a blind spot for the driver (for example, an approaching vehicle or a pedestrian), and collects information such as the distance and speed from the host vehicle to the object. Note that a quasi-millimeter-wave radar may also be attached to the left and right rear ends of the front bumper or the like to detect an object diagonally in front of the vehicle.

[0016] The information collected by the millimeter-wave radar 11, the camera sensor 12, and the BSM 13 respectively is transmitted to the ACC controller 30 via an in-vehicle communication network such as a Controller Area Network (CAN). Note that the configuration of the surrounding situation detection unit 10 is not limited to the above example, and may include an ultrasonic sensor, a LiDAR (Light Detection and Ranging), or the like.

[0017] The vehicle state detection unit 20 has, for example, a vehicle speed sensor 21, an acceleration sensor 22, a brake sensor 23, a steering angle sensor 24, an accelerator opening sensor 25, a traveling direction detector 26, and a direction indicator 27.

[0018] The vehicle speed sensor 21 detects the traveling speed of the host vehicle and generates a signal indicating the traveling speed. The acceleration sensor 22 is a capacitance type sensor or the like mounted on the host vehicle, detects the acceleration of the host vehicle, and generates a signal indicating the acceleration. The brake sensor 23 detects the brake hydraulic pressure of the host vehicle (the hydraulic pressure of the master cylinder that changes according to the depression amount of the brake pedal) and generates a signal indicating the brake hydraulic pressure.

[0019] The steering angle sensor 24 detects the steering angle of the steering wheel of the host vehicle and generates a signal indicating the steering angle. The accelerator opening sensor 25 detects the displacement amount of the accelerator pedal of the host vehicle or the shaft rotation angle of the throttle valve of the engine, and generates a signal indicating the detection result.

[0020] The traveling direction detector 26 detects the traveling direction of the host vehicle using a gyro sensor or the like mounted on the host vehicle, and generates a signal indicating the detection result. The direction indicator 27 is a device for indicating its direction to the surroundings when turning right or left or changing the driving route, and generates a signal indicating the current operating state.

[0021] The signals respectively generated by the vehicle speed sensor 21, the acceleration sensor 22, the brake sensor 23, the steering angle sensor 24, the accelerator opening sensor 25, the traveling direction detector 26, and the direction indicator 27 are transmitted to the ACC controller 30 via the in-vehicle communication network.

[0022] The ACC controller 30 has, for example, an obstacle recognition unit 31, a preceding vehicle recognition unit 32, a traveling lane recognition unit 33, an interrupting vehicle recognition unit 34, a surrounding situation recognition unit 35, a traveling control unit 36, and a display control unit 37.

[0023] The obstacle recognition unit 31 recognizes obstacles located around the host vehicle based on information from the millimeter-wave radar 11, the camera sensor 12, and the BSM 13. The obstacle recognition unit 31 can calculate the relative distance between the recognized obstacle and the host vehicle. Information about the obstacles recognized by the obstacle recognition unit 31 is transmitted to the driving control unit 36.

[0024] The preceding vehicle recognition unit 32 recognizes a preceding vehicle traveling in front of the host vehicle based on information from the millimeter-wave radar 11 and the camera sensor 12 that captures the front of the vehicle. Depending on the performance of the millimeter-wave radar 11 and / or the camera sensor 12, the preceding vehicle recognition unit 32 may be able to recognize a preceding vehicle traveling in front of the host vehicle and a vehicle traveling in front of the preceding vehicle (two preceding vehicles). The preceding vehicle recognition unit 32 can calculate the relative distance (inter-vehicle distance from the preceding vehicle), the traveling speed, and the acceleration of the recognized preceding vehicle. Information about the preceding vehicle recognized by the preceding vehicle recognition unit 32 is transmitted to the driving control unit 36.

[0025] The driving lane recognition unit 33 recognizes the lane in which the host vehicle is traveling and the lanes adjacent to the driving lane of the host vehicle by detecting white lines or the like drawn on the road surface mainly based on information from the camera sensor 12. Information about the driving lane and the adjacent lanes of the host vehicle recognized by the driving lane recognition unit 33 is transmitted to the driving control unit 36.

[0026] The cut-in vehicle recognition unit 34 recognizes (infers and detects) the cut-in of other vehicles in front of the host vehicle based on the information from the millimeter-wave radar 11, the camera sensor 12, and the BSM 13. Specifically, assuming a situation where the host vehicle in motion is overtaken by another vehicle from behind, the cut-in vehicle recognition unit 34 detects another vehicle traveling diagonally behind the host vehicle based on the information from the BSM 13 (quasi-millimeter-wave radar) provided at the left and right rear ends of the rear bumper, and acquires information such as the speed and acceleration of the other vehicle. Then, when the host vehicle is overtaken by another vehicle, the cut-in vehicle recognition unit 34 detects another vehicle (overtaking vehicle) traveling diagonally in front of the host vehicle based on the information from the camera sensor 12 that captures the sides and front of the vehicle, and the millimeter-wave radar 11 provided at the front of the vehicle, and continues to acquire information such as the speed and acceleration of the other vehicle.

[0027] At this time, the cut-in vehicle recognition unit 34 monitors the behavior (intention) of the other vehicle to cut in front of the host vehicle and infers the cut-in of the other vehicle. Examples of the behavior of the other vehicle's cut-in include, for example, the behavior of the other vehicle (such as lateral movement in the direction approaching the host vehicle's driving lane) and the lighting on the host vehicle side of the direction indicator of the other vehicle. When the cut-in vehicle recognition unit 34 infers the cut-in of the other vehicle, the inference result is transmitted to the driving control unit 36 together with information such as the speed and acceleration of the other vehicle.

[0028] Furthermore, the cut-in vehicle recognition unit 34 detects that the other vehicle that has inferred the cut-in has entered the host vehicle's driving lane and has actually cut in front of the host vehicle. This detection of the cut-in of the other vehicle is performed when there is a preceding vehicle in the host vehicle's driving lane and another vehicle cuts in between the preceding vehicle and the host vehicle. When the cut-in vehicle recognition unit 34 detects the cut-in of the other vehicle, the detection result is transmitted to the driving control unit 36 together with information such as the speed and acceleration of the other vehicle (cut-in vehicle). In this embodiment, the cut-in vehicle recognition unit 34 corresponds to the "cut-in detection means" of the present invention.

[0029] The surrounding situation recognition unit 35 mainly recognizes the traffic situation (such as traffic jams, lane regulations, maximum speed, etc.) around the host vehicle based on the information from the camera sensor 12. The information regarding the surrounding situation recognized by the surrounding situation recognition unit 35 is transmitted to the driving control unit 36.

[0030] Based on the signal from the vehicle state detection unit 20 and the information recognized by the obstacle recognition unit 31, the preceding vehicle recognition unit 32, the driving lane recognition unit 33, the interrupting vehicle recognition unit 34, and the surrounding situation recognition unit 35 respectively, when there is no preceding vehicle, the driving control unit 36 performs constant-speed driving at the set vehicle speed, and when there is a preceding vehicle, it generates a driving control command for performing following driving while maintaining the set inter-vehicle time to follow the preceding vehicle. In this embodiment, the driving control unit 36 corresponds to the "adaptive cruise control means" of the present invention.

[0031] Specifically, for the driving control unit 36, the speed of the host vehicle that serves as a reference when performing constant-speed driving is set by the driver, and the inter-vehicle time between the preceding vehicle and the host vehicle that serves as a reference when performing following driving of the preceding vehicle is set. In this embodiment, as the set vehicle speed in constant-speed driving, any vehicle speed equal to or higher than a predetermined lower limit value (for example, 40 km / h, etc.) can be selected, and during the implementation of constant-speed driving, the set value can be increased or decreased by the driver's switch operation.

[0032] Also, the set inter-vehicle time with the preceding vehicle in following driving is divided into a plurality of levels, such as three levels of "Short", "Middle", and "Long", for example, and any one of the plurality of levels can be selected as the initial value according to the driver's preference, etc. Taking a specific example of the set inter-vehicle time, it is possible to set "Short" to 1.5 seconds, "Middle" to 2.0 seconds, "Long" to 2.5 seconds, etc.

[0033] In the above example, when the host vehicle is traveling at 80 km / h, the inter-vehicle distance from the preceding vehicle is approximately 33 m for the "short" set inter-vehicle time (1.5 seconds), approximately 44 m for the "medium" set inter-vehicle time (2.0 seconds), and approximately 56 m for the "long" set inter-vehicle time (2.5 seconds). Also, when the host vehicle is traveling at 50 km / h, the inter-vehicle distance from the preceding vehicle is approximately 21 m for the "short" set inter-vehicle time (1.5 seconds), approximately 28 m for the "medium" set inter-vehicle time (2.0 seconds), and approximately 35 m for the "long" set inter-vehicle time (2.5 seconds). Thus, when following the preceding vehicle while maintaining any one of the "short", "medium", or "long" set inter-vehicle times, the inter-vehicle distance from the preceding vehicle changes according to the speed of the host vehicle.

[0034] When the interruption vehicle recognition unit 34 estimates an interruption by another vehicle, the travel control unit 36 switches the set inter-vehicle time Tps with the preceding vehicle to a set inter-vehicle time Tps' that is greater than or equal to a second threshold TH2 that is greater than a first threshold TH1 when the set inter-vehicle time Tps with the preceding vehicle is less than or equal to the first threshold TH1 (Tps ≦ TH1). Regarding the setting of the first and second thresholds TH1 and TH2, when the set inter-vehicle time with the preceding vehicle is divided into three levels of "short", "medium", and "long" as described above, it is possible to set the first threshold TH1 to the same value as "medium" of the set inter-vehicle time and set the second threshold TH2 to the same value as "long" of the set inter-vehicle time.

[0035] However, in the present embodiment, when the signal from the vehicle speed sensor 21 of the vehicle state detection unit 20 indicates that the host vehicle is decelerating, or when it is determined that the host vehicle is in a state where deceleration is required to perform constant speed travel or to follow the preceding vehicle, even if the set inter-vehicle time Tps with the preceding vehicle is less than or equal to the first threshold TH1 (Tps ≦ TH1), switching of the set inter-vehicle time Tps to a set inter-vehicle time Tps' that is greater than or equal to the second threshold TH2 is aborted and the set inter-vehicle time Tps is maintained.

[0036] On the one hand, when the interruption vehicle recognition unit 34 infers an interruption by another vehicle, the travel control unit 36 maintains the set inter-vehicle time Tps with the preceding vehicle when the set inter-vehicle time Tps with the preceding vehicle exceeds the first threshold TH1 (Tps>TH1).

[0037] At the stage where an interruption by another vehicle as described above is inferred, the travel control unit 36 determines whether the signal from the acceleration sensor 22 of the vehicle state detection unit 20 indicates that the host vehicle is accelerating, or whether the host vehicle is in a state where acceleration is required to perform constant-speed travel or follow the preceding vehicle. Then, when the host vehicle is accelerating or in a state where acceleration is required, the travel control unit 36 generates a travel control command to make the acceleration of the host vehicle when an interruption by another vehicle is inferred smaller than the acceleration of the host vehicle when no interruption by another vehicle is inferred. The details of the travel control at the stage where an interruption by another vehicle is inferred will be described in detail later with specific examples.

[0038] In addition, when the interruption vehicle recognition unit 34 actually detects an interruption by another vehicle in front of the host vehicle, the travel control unit 36 switches the set inter-vehicle time to a set inter-vehicle time Tps” that is equal to or less than the first threshold TH1 (Tps”≦TH1) when the actual inter-vehicle time Tc with the other vehicle (interruption vehicle) is equal to or less than the set inter-vehicle time with the preceding vehicle at that time (Tc≦Tps or Tps’).

[0039] However, in the present embodiment, when the interruption vehicle recognition unit 34 detects an interruption by another vehicle during constant-speed travel at a set vehicle speed without a preceding vehicle, if the speed of the other vehicle (interruption vehicle) is higher than the speed of the host vehicle, even if the actual inter-vehicle time Tc with the other vehicle is equal to or less than the set inter-vehicle time with the preceding vehicle (Tc≦Tps or Tps’), the travel control unit 36 maintains the set inter-vehicle time (Tps or Tps’) and aborts the switch to the set inter-vehicle time Tps” that is equal to or less than the first threshold TH1.

[0040] That is, in the present embodiment, when the interruption vehicle recognition unit 34 detects an interruption by another vehicle, the travel control unit 36, if the actual inter-vehicle time Tc with the other vehicle exceeds the set inter-vehicle time (Tps or Tps’) with the preceding vehicle, or if the speed of the other vehicle is higher than the speed of the host vehicle during constant-speed travel and the actual inter-vehicle time Tc with the other vehicle is less than or equal to the set inter-vehicle time (Tps or Tps’) with the preceding vehicle, maintains the set inter-vehicle time, and in other cases, switches the set inter-vehicle time to a set inter-vehicle time Tps” that is less than or equal to the first threshold TH1. The set inter-vehicle time Tps” with the preceding vehicle that has been switched to be less than or equal to the first threshold TH1 is restored to the initial set inter-vehicle time Tps after a predetermined waiting time Tw has elapsed since the interruption of the other vehicle was detected, or after the travel control unit 36 determines that the other vehicle is in constant-speed travel.

[0041] Furthermore, when the interruption vehicle recognition unit 34 detects an interruption by another vehicle during the follow-up travel of the preceding vehicle, the travel control unit 36 in the present embodiment performs travel control so as to maintain the current speed of the host vehicle under the following conditions. That is, when the speed of the other vehicle (interruption vehicle) is higher than the speed of the host vehicle and the actual inter-vehicle time Tc with the other vehicle exceeds the set inter-vehicle time (Tps, Tps’ or Tps”) with the preceding vehicle, the travel control unit 36 maintains the current speed of the host vehicle until the deceleration of the other vehicle is detected or until the first vehicle speed maintenance time Tm1 elapses.

[0042] On the other hand, when the speed of the other vehicle (interruption vehicle) is higher than the speed of the host vehicle, the actual inter-vehicle time Tc with the other vehicle is less than or equal to the set inter-vehicle time (Tps, Tps’ or Tps”) with the preceding vehicle, and the actual inter-vehicle time Tc with the other vehicle exceeds the shortest inter-vehicle time Tmin at the current speed of the host vehicle, the travel control unit 36 maintains the current speed of the host vehicle until the deceleration of the other vehicle is detected or until the second vehicle speed maintenance time Tm2, which is shorter than the first vehicle speed maintenance time Tm1, elapses. Details of the travel control at the stage when an interruption by another vehicle is detected will also be described in detail later with specific examples.

[0043] The display control unit 37 generates a control signal for causing the display unit 50 to display information indicating the control state of the ACC according to the driving control command generated by the driving control unit 36. The information indicating the control state of the ACC includes the set vehicle speed in the constant-speed driving by the ACC, the set inter-vehicle distance (set inter-vehicle time with the preceding vehicle) in the following driving of the preceding vehicle, the controlled vehicle speed and controlled inter-vehicle distance of the host vehicle actually controlled by the ACC, and information regarding the surrounding situation of the host vehicle recognized by the surrounding situation recognition unit 35, etc.

[0044] The vehicle control unit 40 has, for example, an engine / motor controller 41, a brake controller 42, an anti-skid device 43, and a transmission controller 44. The vehicle control unit 40 controls the driving state of the host vehicle according to the driving control command generated by the driving control unit 36 so that the engine / motor controller 41, the brake controller 42, the anti-skid device 43, and the transmission controller 44 cooperate to realize constant-speed driving by the ACC or following driving of the preceding vehicle.

[0045] The engine / motor controller 41 controls the driving state of a power source (not shown) such as an engine and / or an electric motor mounted on the host vehicle. The brake controller 42 controls the operating state of a braking device (not shown) such as a foot brake (hydraulic brake) or an electric parking brake mounted on the host vehicle.

[0046] The anti-skid device 43 is a type of device that stabilizes the attitude of the host vehicle during turning and is also called ESC (Electronic Stability Control). When the anti-skid device 43 detects that the host vehicle is in an unstable state such as oversteer or understeer, it automatically integrally controls the brake and the engine / motor output to suppress and stabilize the sudden behavior change of the host vehicle. The transmission controller 44 controls the automatic transmission mounted on the host vehicle to an optimal state according to the speed and accelerator opening degree of the host vehicle, etc.

[0047] The display unit 50 is provided, for example, on a meter panel or the like disposed in front of the driver's seat of the vehicle, and has a set vehicle speed display area 51, a set inter-vehicle distance display area 52, a controlled vehicle speed display area 53, a controlled inter-vehicle distance display area 54, and a surrounding situation display area 55. In the set vehicle speed display area 51, the set vehicle speed in the constant speed running by ACC is displayed according to the control signal from the display control unit 37. In the set inter-vehicle distance display area 52, the set inter-vehicle distance (set inter-vehicle time with the preceding vehicle) in the following running of the preceding vehicle is displayed according to the control signal from the display control unit 37.

[0048] In the controlled vehicle speed display area 53, the speed of the host vehicle actually controlled by ACC is displayed according to the control signal from the display control unit 37. In the controlled inter-vehicle distance display area 54, information regarding the inter-vehicle distance from the preceding vehicle actually controlled by ACC is displayed according to the control signal from the display control unit 37. In the surrounding situation display area 55, information regarding the surrounding situation of the host vehicle is displayed according to the control signal from the display control unit 37. Details of each display area of the display unit 50 will also be described in detail later with specific examples.

[0049] Next, the operation of the vehicle control device 1 according to the present embodiment will be described. FIG. 2 is a flowchart showing the flow of the running control by ACC in the present embodiment. In the vehicle control device 1 configured as described above, first, in step S10 of FIG. 2, the ACC controller 30 determines whether or not the ACC function of the host vehicle has been activated. The activation of the ACC function is performed, for example, by the driver of the host vehicle traveling on a public road pressing a main switch (not shown) provided on the steering wheel.

[0050] When it is determined that the ACC function is activated, in the next step S20, the driver of the host vehicle initializes the vehicle speed in the constant-speed driving by ACC and the inter-vehicle time between the host vehicle and the preceding vehicle in the following driving to the control device 1. The set vehicle speed for the constant-speed driving is, for example, performed when the host vehicle is traveling at 40 km / h or more and the driver presses the "SET / -" button (not shown) on the steering wheel. A display indicating that the ACC is operating is made on the display unit 50 in the meter panel, and the initialized vehicle speed is displayed in the set vehicle speed display area 51. The driver can increase the set vehicle speed by pressing the "RES / +" button (not shown) on the steering wheel according to preference, and can decrease the set vehicle speed by pressing the "SET / -" button on the steering wheel.

[0051] Also, the set inter-vehicle time with the preceding vehicle is initialized each time the driver presses the inter-vehicle setting button (not shown) on the steering wheel, and "Short", "Middle", and "Long" are sequentially switched. A display corresponding to the set inter-vehicle time Tps with the preceding vehicle is made in the set inter-vehicle display area 52 of the display unit 50. In the following operation description, the case where the set inter-vehicle time Tps with the preceding vehicle is short may be denoted as "Tps(S)", the case of middle as "Tps(M)", and the case of long as "Tps(L)".

[0052] In the subsequent step S30, the driving control unit 36 of the ACC controller 30 determines whether a preceding vehicle has been recognized by the preceding vehicle recognition unit 32. When a preceding vehicle is recognized (YES), in step S40, the driving control unit 36 performs following driving control to follow the preceding vehicle while maintaining the set inter-vehicle time Tps. In the following driving control, the speed of the host vehicle is accelerated or decelerated according to the speed of the preceding vehicle, so that the actual inter-vehicle time Tp with the preceding vehicle is maintained at the set inter-vehicle time Tps. When corresponding to the full vehicle speed following function, it is possible to follow until the preceding vehicle stops. On the other hand, when no preceding vehicle is recognized (NO in S30), in step S50, the driving control unit 36 performs constant speed driving control at the set vehicle speed (40 km / h or more). The speed of the host vehicle controlled by the following driving control or the constant speed driving control is displayed in the controlled vehicle speed display area 53 of the display unit 50 by the display control unit 37.

[0053] In the next step S60, the driving control unit 36 of the ACC controller 30 determines whether an intrusion of another vehicle into the front of the host vehicle has been estimated by the intrusion vehicle recognition unit 34 during the execution of the above-described following driving control or constant speed driving control. When an intrusion of another vehicle is estimated (YES), in step S70, setting switching processing based on the intrusion estimation is performed. On the other hand, when no intrusion of another vehicle is estimated (NO), the process proceeds to step S100 described later.

[0054] Here, the setting switching process based on the intrusion estimation in step S70 will be described in detail with reference to the specific examples shown in FIGS. 3 to 6 and the flowchart shown in FIG. 7. Figs. 3 to 5 are diagrams for explaining the switching of the set inter-vehicle time Tps when an intrusion of another vehicle is estimated. Fig. 3 shows an example when the initial set inter-vehicle time Tps is "short", Fig. 4 shows an example when the initial set inter-vehicle time Tps is "medium", and Fig. 5 shows an example when the initial set inter-vehicle time Tps is "long". Fig. 6 is a diagram showing an example of information displayed on the display unit 50 in the meter panel corresponding to the switching of Fig. 3. In Figs. 3 to 6, an example of estimating an intrusion of another vehicle during following travel of the preceding vehicle is described, but when an intrusion of another vehicle is estimated during constant-speed travel, the set inter-vehicle time Tps is switched in the same manner as during following travel.

[0055] First, as shown in the first stage of Fig. 3, while the host vehicle 61 is following the preceding vehicle 62 while maintaining the "short" set inter-vehicle time Tps(S), when another vehicle 63 traveling in the same direction as the host vehicle 61 is detected by the BSM 13 diagonally behind the host vehicle 61, the other vehicle 63 becomes a monitoring target by the ACC controller 30 as a vehicle that may make an intrusion. Note that the inter-vehicle distance DS(60) between the host vehicle 61 and the preceding vehicle 62 shown in the first stage of Fig. 3 represents the inter-vehicle distance when the host vehicle 61 is traveling at a speed V1 = 60 km / h in the set inter-vehicle time Tps(S).

[0056] At this stage, since it is not known whether the other vehicle 63 will overtake the host vehicle 61, the state of estimating the intrusion of the other vehicle 63 has not been reached. In such a state where the host vehicle 61 is following the preceding vehicle 62 while maintaining the "short" set inter-vehicle time Tps(S), information as shown in the first stage of Fig. 6, for example, is displayed on the display unit 50. Specifically, in the example of Fig. 6, "ACC SET" indicating that the ACC is operating is displayed in the set vehicle speed display area 51 of the display unit 50, and the set vehicle speed "50 km / h" in constant-speed travel is displayed. Also, in the surrounding situation display area 55, the running lane and the icon of the preceding vehicle 62 are displayed, and in the set inter-vehicle display area 52, one line representing the "short" set inter-vehicle time Tps(S) with the preceding vehicle 62 is displayed. Further, in the controlled vehicle speed display area 53, the current running speed "60 km / h" of the host vehicle 61 is displayed.

[0057] Then, as shown in the second row of FIG. 3, when another vehicle 63 overtakes the host vehicle 61 and moves diagonally in front of the host vehicle 61, the host vehicle 61 is detected by a camera sensor 12 that captures the sides and front of the host vehicle 61, and a millimeter-wave radar 11 provided at the front of the vehicle. As a result, the ACC controller 30 acquires information regarding the speed, acceleration, vehicle behavior, and the lighting state of the turn signal of the other vehicle 63. Then, based on the acquired information, when the ACC controller 30 detects a lateral movement of the other vehicle 63 in a direction approaching the driving lane of the host vehicle 61, or lighting on the host vehicle 61 side of the turn signal of the other vehicle 63, etc., the ACC controller 30 infers an intrusion of the other vehicle 63 in front of the host vehicle 61. When an intrusion of the other vehicle 63 is inferred, in addition to the driving lane and the icon of the preceding vehicle 62 displayed in the surrounding situation display area 55, as shown in the second row of FIG. 6, an icon of the adjacent lane and the other vehicle 63 is displayed on the display unit 50.

[0058] Since the set inter-vehicle time Tps (S) with the preceding vehicle 62 is equal to or less than the first threshold TH1 (in this embodiment, "short" or "medium" applies), the ACC controller 30 that has inferred an intrusion of the other vehicle 63 switches the set inter-vehicle time Tps (S) to a set inter-vehicle time Tps' that is equal to or greater than the second threshold TH2 (in this embodiment, "medium" or "long" applies). In the example of FIG. 3, the "short" set inter-vehicle time Tps (S) is switched to the "long" set inter-vehicle time Tps' (L). Although not shown here, the "short" set inter-vehicle time Tps (S) may be switched to the "medium" set inter-vehicle time Tps' (M).

[0059] When the set inter-vehicle time with the preceding vehicle 62 switches from Tps (S) to Tps' (L), on the display unit 50, as shown in the third row of FIG. 6, information notifying the driver that the inter-vehicle distance has been temporarily widened due to the inference of an intrusion of the other vehicle 63 is displayed in the popped-up control inter-vehicle display area 54. Then, as shown in the fourth row of FIG. 6, three lines representing the set inter-vehicle time Tps' (L) switched from "short" to "long" are displayed in the set inter-vehicle display area 52.

[0060] At this time, the travel control unit 36 of the ACC controller 30 performs travel control to gently decrease the speed V1 of the host vehicle 61 so that the actual inter-vehicle time Tp with the preceding vehicle 62 approaches the set inter-vehicle time Tps’(L). The deceleration of the host vehicle 61 at this time is smaller than the deceleration when the brake of the host vehicle 61 is actuated to maintain the set inter-vehicle time Tps(S) in the follow-up travel of the preceding vehicle 62 before predicting the interruption. In the example shown in the third row of FIG. 3, when the host vehicle 61 reaches a speed V1 = 50 km / h, the actual inter-vehicle time Tp with the preceding vehicle 62 corresponding to the set inter-vehicle time Tps’(L) of “long” is ensured. The inter-vehicle distance DL(50) with the preceding vehicle 62 in this state represents the inter-vehicle distance when the host vehicle 61 is traveling at a speed V1 = 50 km / h at the set inter-vehicle time Tps’(L). After the inter-vehicle distance DL(50) with the preceding vehicle 62 is ensured, the speed V1 of the host vehicle 61 is accelerated or decelerated according to the speed of the preceding vehicle 62, and the actual inter-vehicle time Tp with the preceding vehicle 62 is maintained at the set inter-vehicle time Tps’(L).

[0061] Also, when the initial set inter-vehicle time Tps with the preceding vehicle 62 shown in FIG. 4 is “medium”, similar to the case where the initial set inter-vehicle time Tps with the preceding vehicle 62 shown in FIG. 3 is “short”, the set inter-vehicle time is switched by predicting the interruption of another vehicle 63. That is, as shown in the first and second rows of FIG. 4, in a state where the host vehicle 61 is following the preceding vehicle 62 while maintaining the set inter-vehicle time Tps(M) of “medium”, another vehicle 63 that has overtaken the host vehicle 61 becomes a monitoring target of the ACC controller 30 as a vehicle that may interrupt. Then, when the ACC controller 30 predicts the interruption of another vehicle 63 in front of the host vehicle 61 based on the behavior of another vehicle 63 and the lighting state of the direction indicator, etc., it switches the set inter-vehicle time Tps(M) with the preceding vehicle 62 to the set inter-vehicle time Tps’(L) of “long”.

[0062] When the set inter-vehicle time with the preceding vehicle 62 switches from Tps(M) to Tps’(L), the travel control unit 36 of the ACC controller 30 gently decreases the speed V1 of the host vehicle 61, so that, as shown in the third stage of FIG. 4, the actual inter-vehicle time Tp with the preceding vehicle 62 corresponding to the set inter-vehicle time Tps’(L) of “long” is ensured. Thereafter, the speed V1 of the host vehicle 61 is accelerated or decelerated according to the speed of the preceding vehicle 62, and the actual inter-vehicle time Tp with the preceding vehicle 62 is maintained at the set inter-vehicle time Tps’(L).

[0063] On the other hand, when the initial set inter-vehicle time Tps with the preceding vehicle 62 shown in FIG. 5 is “long”, a process based on interrupt prediction different from the case where the initial set inter-vehicle time Tps is “short” or “medium” described above is performed. That is, as shown in the first and second stages of FIG. 5, in a state where the host vehicle 61 is following the preceding vehicle 62 while maintaining the set inter-vehicle time Tps(L) of “long”, the other vehicle 63 that has overtaken the host vehicle 61 becomes a monitoring target of the ACC controller 30 as a vehicle that may interrupt. Then, when the ACC controller 30 infers the interruption of the other vehicle 63 in front of the host vehicle 61 based on the behavior of the other vehicle 63 and the lighting state of the direction indicator, etc., since the set inter-vehicle time Tps(L) of the inter-vehicle time with the preceding vehicle 62 exceeds the first threshold TH1, the set inter-vehicle time Tps(L) is maintained.

[0064] When the initial set inter-vehicle time Tps with the preceding vehicle 62 is set to a relatively long inter-vehicle time exceeding the first threshold TH1 as described above, by maintaining the current state without performing a switch to extend the set inter-vehicle time, the deceleration of the host vehicle that occurs immediately after the switch of the set inter-vehicle time as in the case where the initial set inter-vehicle time Tps is below the first threshold TH1 is suppressed (the second and third stages of FIG. 5).

[0065] Also, the switching from the set inter-vehicle time Tps(S) to Tps’(L) (or Tps’(M)) at the intrusion prediction stage of the other vehicle 63 described above, and the switching from Tps(M) to Tps’(L) are aborted when the host vehicle 61 is decelerating or in a state where deceleration is required (hereinafter referred to as “deceleration state”), and the initial set inter-vehicle times Tps(S) and Tps(M) are maintained. This is because if the set inter-vehicle time with the preceding vehicle 62 is extended in the deceleration state of the host vehicle 61, in addition to the current deceleration, deceleration is required to increase the inter-vehicle time with the preceding vehicle 62, resulting in a larger deceleration or an increase in the time and number of times the brake is actuated. This is a measure to avoid such situations.

[0066] Furthermore, at the intrusion prediction stage of the other vehicle 63, when the host vehicle 61 is accelerating or in a state where acceleration is required (hereinafter referred to as “acceleration state”), driving control is performed so that the acceleration when an intrusion is predicted is smaller than the acceleration when no intrusion is predicted. Specifically, for example, when the acceleration of the host vehicle 61 when no intrusion is predicted is 2.5 m / s 2 in a certain case, it is possible to perform driving control so that the acceleration when an intrusion is predicted becomes 1.0 m / s 2 By gently reducing the acceleration of the host vehicle 61 when an intrusion of the other vehicle 63 is predicted in this way, it becomes possible to reduce the gap with the deceleration of the host vehicle 61 caused by the switching of the set inter-vehicle time with the preceding vehicle 62, or the gap with the deceleration of the host vehicle 61 when the other vehicle 63 actually intrudes.

[0067] FIG. 7 is a flowchart showing a specific example of the switching process of the set inter-vehicle time with the preceding vehicle 62 (step S70 in FIG. 2) at the intrusion prediction stage of the other vehicle 63 as described above. First, in step S210 of FIG. 7, the travel control unit 36 of the ACC controller 30 determines whether the host vehicle 61 is in a decelerated state in response to the interruption of the other vehicle 63 being estimated in step S60 of FIG. 2 described above. If the host vehicle 61 is not in a decelerated state (NO), the process proceeds to the next step S220. If the host vehicle 61 is in a decelerated state (YES), the process moves to the process of step S80 (FIGS. 2 and 7) following the setting switching process by interruption estimation (step S70 of FIG. 2).

[0068] In step S220, the travel control unit 36 of the ACC controller 30 determines whether the host vehicle 61 is in an accelerated state. If the host vehicle 61 is in an accelerated state (YES), in the next step S230, the travel control unit 36 controls the travel of the host vehicle 61 so that the acceleration when the interruption is estimated is smaller than the acceleration when the interruption is not estimated. On the other hand, if the host vehicle 61 is not in an accelerated state (NO), the process moves to the process of step S240.

[0069] In step S240, the travel control unit 36 of the ACC controller 30 determines whether the initial set inter-vehicle time Tps with the preceding vehicle 62 is equal to or less than the first threshold value TH1. If the set inter-vehicle time Tps is equal to or less than the first threshold value TH1 (YES), in the next step S250, the travel control unit 36 switches the set inter-vehicle time Tps with the preceding vehicle 62 to a set inter-vehicle time Tps' that is equal to or greater than the second threshold value TH2. On the other hand, if the initial set inter-vehicle time Tps exceeds the first threshold value TH1 (NO), the process moves to the process of the above step S80 (FIGS. 2 and 7).

[0070] In step S80, the travel control unit 36 of the ACC controller 30 determines whether or not an interruption of another vehicle 63 in front of the host vehicle 61 has been detected by the interruption vehicle recognition unit 34. If an interruption of another vehicle 63 is detected (YES), in step S90 (Figs. 2 and 7), setting switching processing based on the interruption detection is performed. Details of the setting switching processing based on the interruption detection will be described later. On the other hand, if no interruption of another vehicle 63 is detected, that is, if the state where an interruption of another vehicle 63 is presumed continues (NO), the process proceeds to step S260 (Fig. 7).

[0071] In step S260, the travel control unit 36 of the ACC controller 30 determines whether or not a predetermined estimation waiting time has elapsed since the interruption of another vehicle 63 was presumed, or whether or not the interruption of another vehicle 63 has been canceled. The cancellation of the interruption of another vehicle 63 is detected, for example, when the other vehicle 63 overtakes not only the host vehicle 61 but also the preceding vehicle 62, or when the other vehicle 63 decelerates and moves to the rear side of the host vehicle 61. If the elapse of the estimation waiting time or the cancellation of the interruption is detected (YES), in the next step S270, the travel control unit 36 returns the set inter-vehicle time with the preceding vehicle 62 and the acceleration of the host vehicle 61 to their original states before the interruption was presumed. Then, the process returns to step S30 (Fig. 2) described above, and a series of processes after step S30 are repeatedly executed. On the other hand, if the elapse of the estimation waiting time and the cancellation of the interruption are not detected (NO in S260), the process returns to step S80 and the interruption detection of another vehicle 63 is determined again.

[0072] Next, the setting switching process based on the interruption detection in step S90 will be described in detail with reference to the specific examples shown in Figs. 8 to 11 and the flowchart shown in Fig. 12. Figs. 8 to 10 are diagrams for explaining the switching of the set inter-vehicle time with the preceding vehicle 62 and the speed control of the host vehicle 61 when an interruption of another vehicle 63 is detected during the follow-up travel of the preceding vehicle 62. Fig. 11 is a diagram for explaining the speed control of the host vehicle 61 when an interruption of another vehicle 63 is detected during the constant speed travel at the set vehicle speed.

[0073] The state shown in the first stage of FIG. 8 corresponds to, for example, the states shown in the third stage of FIGS. 3 and 4 described above. The host vehicle 61 follows the preceding vehicle 62 while maintaining the set inter-vehicle time Tps’(L) of “long” by predicting the intrusion of the other vehicle 63 and is traveling at a speed V1 = 50 km / h. In such a traveling state of the host vehicle 61, when the other vehicle 63 enters the traveling lane of the host vehicle 61 as shown in the second stage of FIG. 8, the ACC controller 30 detects the intrusion of the other vehicle 63. The intrusion of the other vehicle 63 is detected when at least a part of the other vehicle 63 enters the traveling lane in front of the host vehicle 61. Although not shown here, for the state in which the set inter-vehicle time Tps(L) was maintained when the intrusion was initially predicted with the set inter-vehicle time Tps(L) of “long” (the third stage of FIG. 5), the setting switching process by intrusion detection is performed in the same manner as in the case of FIG. 8.

[0074] The ACC controller 30 that has detected the intrusion of the other vehicle 63 acquires information regarding the speed V3, acceleration, and the actual inter-vehicle time Tc between the host vehicle 61 and the other vehicle 63 of the other vehicle 63 (intruding vehicle). Then, when the actual inter-vehicle time Tc with the other vehicle 63 is equal to or less than the set inter-vehicle time Tps’(L) with the preceding vehicle 62, the ACC controller 30 switches the setting of the set inter-vehicle time Tps’(L) to a shorter set inter-vehicle time Tps”. In the example of FIG. 8, the set inter-vehicle time Tps’(L) of “long” is switched to the set inter-vehicle time Tps”(S) of “short”. Although not shown here, the set inter-vehicle time Tps’(L) of “long” may be switched to the set inter-vehicle time Tps”(M) of “medium”.

[0075] When an intrusion of another vehicle 63 is detected and no switching is performed to shorten the set inter-vehicle time with the preceding vehicle 62 as described above, when the other vehicle 63 that has intruded in front of the host vehicle 61 becomes the target vehicle (new preceding vehicle) for following travel, it becomes necessary to significantly decelerate the host vehicle 61 in order to make the actual inter-vehicle time Tc with the other vehicle 63 approach the set inter-vehicle time Tps’(L). Such a significant deceleration of the host vehicle 61 when the other vehicle 63 actually intrudes can be effectively suppressed by switching the set inter-vehicle time from Tps’(L) to Tps”(S).

[0076] In the example of FIG. 8, since the actual inter-vehicle time Tc with the other vehicle 63 at the time of detecting the intrusion is slightly longer than the set inter-vehicle time Tps”(S) after switching, even when the other vehicle 63 becomes the target vehicle for following travel, the host vehicle 61 is hardly decelerated, and the speed V1 of the host vehicle 61 is controlled in accordance with the speed of the other vehicle 63 while maintaining the set inter-vehicle time Tps”(S). In the third row of FIG. 8, a state is illustrated in which the host vehicle 61 follows while keeping the actual inter-vehicle time Tc with the other vehicle 63 at the set inter-vehicle time Tps”(S) at a speed V1 = 60 km / h.

[0077] Then, as shown in the fourth row of FIG. 8, the ACC controller 30 returns the set inter-vehicle time Tps”(S) with the other vehicle 63 (new preceding vehicle) to the initial set inter-vehicle time Tps after a predetermined detection waiting time has elapsed since detecting the intrusion of the other vehicle 63, or after determining the constant-speed travel of the other vehicle 63. In the example of FIG. 8, the set inter-vehicle time with the new preceding vehicle is returned from Tps”(S) to Tps(M). Thereby, the travel control by the ACC similar to that before estimating and detecting the intrusion of the other vehicle 63 is continued.

[0078] When detecting the intrusion of the other vehicle 63 during the following travel of the preceding vehicle 62 as described above and performing the switching of the set inter-vehicle time, it is preferable that the ACC controller 30 controls the speed of the host vehicle 61 as shown in FIGS. 9 and 10. First, as shown in the first and second lines of FIG. 9, while the host vehicle 61 is following the preceding vehicle 62 at a speed V1 = 50 km / h, assume that another vehicle 63 cuts in at a speed V3 faster than the host vehicle 61 (V3 > V1), and the actual inter-vehicle time Tc with the other vehicle 63 exceeds the set inter-vehicle time Tps”(S) with the preceding vehicle 62 after the switch.

[0079] In this case, the host vehicle 61 will be accelerated so that the actual inter-vehicle time Tc with the cutting-in other vehicle 63 approaches the set inter-vehicle time Tps”(S). However, the speed V3 of the other vehicle 63 that cuts in at a speed V3 faster than the host vehicle 61 is likely to decrease to about the same speed as the preceding vehicle 62 that the host vehicle 61 was following before the cut-in. For this reason, as shown in the third line of FIG. 9, the ACC controller 30 performs running control so that the current speed V1 = 50 km / h of the host vehicle 61 is maintained until the deceleration of the other vehicle 63 is detected or until the first vehicle speed maintenance time Tm1 elapses after the detection of the cut-in of the other vehicle 63. The elapse of the first vehicle speed maintenance time Tm1 is a condition considering the case where the speed V3 of the other vehicle 63 does not decrease. By maintaining the speed V1 of the host vehicle 61 as described above, unnecessary acceleration and deceleration of the host vehicle 61 after the detection of the cut-in are suppressed.

[0080] After the detection of the deceleration of the other vehicle 63 or the elapse of the first vehicle speed maintenance time Tm1, the ACC controller 30 controls the speed V1 of the host vehicle 61 according to the speed V3 of the other vehicle 63. When it is determined that the detection waiting time has elapsed or the other vehicle 63 is traveling at a constant speed, the set inter-vehicle time is returned to the initial state from Tps”(S), and running control is performed to follow the other vehicle 63 (the new preceding vehicle) while maintaining the set inter-vehicle time. The fourth line of FIG. 9 shows a state where the host vehicle 61 is following the other vehicle 63 at a speed V1 = 60 km / h while maintaining the initial set inter-vehicle time Tps(M).

[0081] On the one hand, as shown in the first and second lines of FIG. 10, while the host vehicle 61 is following the preceding vehicle 62 at a speed V1 = 50 km / h, another vehicle 63 cuts in at a speed V3 faster than the host vehicle 61 (V3 > V1), and the actual inter-vehicle time Tc with the other vehicle 63 is less than or equal to the set inter-vehicle time Tps”(S) with the preceding vehicle 62 after switching, and the actual inter-vehicle time Tc with the other vehicle 63 exceeds the shortest inter-vehicle time Tmin at the current speed V1 of the host vehicle 61. Assume this case.

[0082] In this case, the host vehicle 61 is temporarily decelerated so that the actual inter-vehicle time Tc with the cutting-in other vehicle 63 approaches the set inter-vehicle time Tps”(S), and when the set inter-vehicle time Tps”(S) is ensured, the host vehicle 61 is accelerated in accordance with the speed V3 of the other vehicle 63. However, as described above, the speed V3 of the other vehicle 63 is likely to decrease to about the same level as the speed of the preceding vehicle 62. For this reason, as shown in the third line of FIG. 10, the ACC controller 30 performs travel control so that the current speed V1 = 50 km / h of the host vehicle 61 is maintained until the deceleration of the other vehicle 63 is detected or until a second vehicle speed maintenance time Tm2 shorter than the first vehicle speed maintenance time Tm1 has elapsed since the intrusion of the other vehicle 63 was detected.

[0083] The reason for setting the second vehicle speed maintenance time Tm2 shorter than the first vehicle speed maintenance time Tm1 is that the comfort of the driver is impaired if the time during which the distance to the cutting-in other vehicle 63 (new preceding vehicle) is short becomes long. By maintaining the speed V1 of the host vehicle 61 as described above, unnecessary acceleration and deceleration of the host vehicle 61 after the intrusion is detected are suppressed. After the deceleration of the other vehicle 63 is detected or after the second vehicle speed maintenance time Tm2 has elapsed, as shown in the fourth line of FIG. 10, the same travel control as in the case of FIG. 9 described above is performed.

[0084] In response to the setting switching process corresponding to the detection of the intrusion of another vehicle 63 during the following driving of the preceding vehicle 62 as described above, when the intrusion of another vehicle 63 is detected during the constant-speed driving at the set vehicle speed without the preceding vehicle 62, the ACC controller 30 performs the driving control as shown in FIG. 11. First, as shown in the first and second steps of FIG. 11, assume a case where the host vehicle 61 is driving at a constant speed of V1 = 50 km / h and another vehicle 63 intrudes at a speed V3 faster than the host vehicle 61. In this case, it is highly likely that the other vehicle 63 will continue to drive at a speed V3 faster than the host vehicle 61 even after the intrusion.

[0085] Therefore, even if the actual inter-vehicle time Tc with the other vehicle 63 is less than or equal to the set inter-vehicle time Tps’(L) with the preceding vehicle at the estimation stage, the ACC controller 30 maintains the set inter-vehicle time Tps’(L) and aborts the switching to the set inter-vehicle time Tps”(S) that is less than or equal to the first threshold TH1 described above. That is, unlike the case of detecting an intrusion during the following driving of the preceding vehicle 62 described above, since it is unlikely that the driving control will cause the brakes of the host vehicle 61 to operate without shortening the set inter-vehicle time, the comfort of the driver can be enhanced by maintaining a sufficient set inter-vehicle time.

[0086] At this time, when the actual inter-vehicle time Tc with the other vehicle 63 exceeds the shortest inter-vehicle time Tmin at the current speed V1 of the host vehicle 61, the ACC controller 30 controls the driving of the host vehicle 61 to maintain the current speed V1 of the host vehicle 61 until the deceleration of the other vehicle 63 is detected or until the second vehicle speed maintenance time Tm2 described above elapses. This is because when the other vehicle 63 intrudes, the control of the host vehicle 61 switches from constant-speed driving to following driving with the other vehicle 63 as the preceding vehicle. However, as described above, it is highly likely that the other vehicle 63 after the intrusion will drive at a speed faster than the host vehicle 61. Therefore, by maintaining the current speed V1 of the host vehicle 61, unnecessary deceleration for ensuring the set inter-vehicle time with the other vehicle 63 is suppressed.

[0087] After detecting the deceleration of the other vehicle 63 or after the elapse of the second vehicle speed maintenance time Tm2, the ACC controller 30 controls the speed V1 of the host vehicle 61 according to the speed V3 of the other vehicle 63, and performs driving control so as to follow the other vehicle 63 as the preceding vehicle while maintaining the set inter-vehicle time Tps’(L). The fourth stage in FIG. 11 shows a state in which the host vehicle 61 follows the other vehicle 63 while maintaining the speed V1 = 60 km / h and the set inter-vehicle time Tps’(L).

[0088] FIG. 12 is a flowchart showing a specific example of the switching process of the set inter-vehicle time with the preceding vehicle 62 in the above-described interruption detection stage of the other vehicle 63 (step S90 in FIGS. 2 and 7). First, in step S310 of FIG. 12, the ACC controller 30 determines whether or not it was following the preceding vehicle 62 before the interruption was detected in step S80 (FIGS. 2 and 7) described above. If it was following (YES), the process proceeds to the process of the next step S320. If it was not following, that is, if it was performing a constant speed driving without the preceding vehicle 62 (NO), the process moves to the process of step S420 described later.

[0089] In step S320, the ACC controller 30 determines whether or not the actual inter-vehicle time Tc with the other vehicle 63 in which the interruption was detected is less than or equal to the set inter-vehicle time Tps’(L) with the preceding vehicle 62. If the actual inter-vehicle time Tc is less than or equal to the set inter-vehicle time Tps’(L) (YES), in the next step S330, the ACC controller 30 switches the set inter-vehicle time to a shorter set inter-vehicle time Tps”. In the present embodiment, the set inter-vehicle time Tps’(L) with the preceding vehicle 62, which is “long”, is switched to Tps”(S), which is “short”. On the other hand, if the actual inter-vehicle time Tc exceeds the set inter-vehicle time Tps’(L) (NO in S320), the process moves to step S340 while maintaining the set inter-vehicle time Tps’(L).

[0090] In step S340, the ACC controller 30 determines whether the speed V3 of the other vehicle 63 (the interrupting vehicle) is higher than the speed V1 of the host vehicle 61. If the speed V3 of the other vehicle 63 is higher than the speed V1 of the host vehicle 61 (YES), in the next step S350, the ACC controller 30 determines whether the actual inter-vehicle time Tc with the other vehicle 63 exceeds the shortest inter-vehicle time Tmin at the current speed V1 of the host vehicle 61. If the actual inter-vehicle time Tc exceeds the shortest inter-vehicle time Tmin (YES), in the subsequent step S360, the ACC controller 30 performs travel control to maintain the current speed V1 of the host vehicle 61 and proceeds to the next step S370. On the other hand, if the speed V3 of the other vehicle 63 is less than or equal to the speed V1 of the host vehicle 61 (NO in S340), or if the actual inter-vehicle time Tc is less than or equal to the shortest inter-vehicle time Tmin (NO in S350), the process proceeds to the process of step S480 described later.

[0091] In step S370, the ACC controller 30 determines whether it has detected deceleration of the other vehicle 63. If it has not detected deceleration of the other vehicle 63 (NO), the process proceeds to the process of the next step S380, and if it has detected deceleration of the other vehicle 63 (YES), the process proceeds to the process of step S410 described later. In step S380, the ACC controller 30 determines whether the second vehicle speed maintenance time Tm2 has elapsed since it detected the interruption of the other vehicle 63. If the second vehicle speed maintenance time Tm2 has elapsed (YES), the process proceeds to the process of the next step S390, and if the second vehicle speed maintenance time Tm2 has not yet elapsed (NO), the process returns to the process of the above step S350.

[0092] In step S390, the ACC controller 30 determines whether the actual inter-vehicle time Tc with the other vehicle 63 exceeds the set inter-vehicle time with the preceding vehicle 62 at that time. If the actual inter-vehicle time Tc exceeds the set inter-vehicle time with the preceding vehicle 62 (YES), the process proceeds to the process of the next step S400, and if the actual inter-vehicle time Tc is less than or equal to the set inter-vehicle time with the preceding vehicle 62 (NO), the process proceeds to the process of step S410.

[0093] In step S400, the ACC controller 30 determines whether or not a first vehicle speed maintenance time Tm1 (>Tm2) has elapsed since detecting an interruption of another vehicle 63. If the first vehicle speed maintenance time Tm1 has elapsed (YES), in the next step S410, the ACC controller 30 ends the maintenance of the current speed of the host vehicle 61 and proceeds to the process of step S480. On the other hand, if the first vehicle speed maintenance time Tm1 has not yet elapsed (NO), the process returns to the process of step S390 above.

[0094] In step S420, in response to determining that the constant speed running was being performed in step S310 described above, the ACC controller 30 determines whether or not the speed V3 of the interrupting other vehicle 63 is higher than the speed V1 of the host vehicle 61. If the speed V3 of the other vehicle 63 is higher than the speed V1 of the host vehicle 61 (YES), the process proceeds to the process of the next step S430. If the speed V3 of the other vehicle 63 is less than or equal to the speed V1 of the host vehicle 61 (NO), the process proceeds to the process of step S320 described above.

[0095] In step S430, the ACC controller 30 determines whether or not the actual inter-vehicle time Tc with the other vehicle 63 exceeds the shortest inter-vehicle time Tmin at the current speed V1 of the host vehicle 61. If the actual inter-vehicle time Tc exceeds the shortest inter-vehicle time Tmin (YES), in the subsequent step S440, the ACC controller 30 performs running control to maintain the current speed V1 of the host vehicle 61 and proceeds to the next step S450. On the other hand, if the actual inter-vehicle time Tc is less than or equal to the shortest inter-vehicle time Tmin (NO in S430), the process proceeds to the process of step S480.

[0096] In step S450, it is determined whether deceleration of the other vehicle 63 is detected. If deceleration of the other vehicle 63 is not detected (NO), the process proceeds to the next step S460. If deceleration of the other vehicle 63 is detected (YES), the process moves to step S470. In step S460, the ACC controller 30 determines whether the second vehicle speed maintenance time Tm2 has elapsed since detecting the interruption of the other vehicle 63. If the second vehicle speed maintenance time Tm2 has elapsed (YES), in the next step S470, the ACC controller 30 ends the maintenance of the current speed V1 of the host vehicle 61 and moves to the process of step S480. On the other hand, if the second vehicle speed maintenance time Tm2 has not yet elapsed (NO in S460), the process returns to the process of step S430 above.

[0097] In step S480, the ACC controller 30 determines whether a predetermined detection waiting time has elapsed since detecting the interruption of the other vehicle, or whether constant-speed running of the other vehicle 63 is detected. When the detection waiting time has elapsed or constant-speed running of the other vehicle 63 is detected (YES), in the next step S490, the ACC controller 30 returns the set inter-vehicle time with the preceding vehicle and the acceleration of the host vehicle to the initial state. Then, the setting switching process by the interruption detection in step S90 shown in FIGS. 2 and 7 is ended, and the process moves to the process of step S100 in FIG. 2.

[0098] In step S100 (FIG. 2), the ACC controller 30 determines whether the ACC function of the vehicle has ended. The end of the ACC function is performed by the driver pressing the main switch or the cancel button (not shown) on the steering wheel. If the ACC function has ended (YES), the driving control by ACC is released. On the other hand, if the ACC function has not ended (NO), the process returns to step S30 and the driving control by ACC continues.

[0099] As described above, in the vehicle control device 1 according to the present embodiment, when an interruption of another vehicle 63 is detected by the ACC controller 30, if the actual inter-vehicle time Tc with the other vehicle 63 is equal to or less than the set inter-vehicle time Tps' with the preceding vehicle 62, the set inter-vehicle time Tps' is switched to a set inter-vehicle time Tps" that is equal to or less than a first threshold TH1 that is shorter than it. By shortening the set inter-vehicle time with the preceding vehicle 62 when another vehicle 63 interrupts in this way, it becomes possible to suppress a large deceleration of the host vehicle 61, so that the comfort of the driver of the host vehicle 61 can be improved.

[0100] Also, in the vehicle control device 1 according to the present embodiment, after a predetermined detection waiting time has elapsed since the interruption of another vehicle 63 was detected by the ACC controller 30, or after it is determined that the other vehicle 63 is traveling at a constant speed, the set inter-vehicle time with the preceding vehicle 62 is returned to the initial state before the interruption detection. As a result, it is possible to follow the preceding vehicle while maintaining the initially set inter-vehicle time desired by the driver, so that the comfort of the driver can be further improved.

[0101] Furthermore, in the vehicle control device 1 according to the present embodiment, when an interruption of another vehicle 63 is detected during following travel of the preceding vehicle 62, if the speed V3 of the other vehicle 63 is higher than the speed V1 of the host vehicle 61, and the actual inter-vehicle time Tc with the other vehicle 63 exceeds the set inter-vehicle time with the preceding vehicle 62, the current speed V1 of the host vehicle 61 is maintained until deceleration of the other vehicle 63 is detected or until a first vehicle speed maintenance time Tm1 elapses. On the other hand, if the speed V3 of the other vehicle 63 is higher than the speed V1 of the host vehicle, the actual inter-vehicle time Tc with the other vehicle 63 is equal to or less than the set inter-vehicle time with the preceding vehicle 62, and the actual inter-vehicle time Tc with the other vehicle 63 exceeds the shortest inter-vehicle time Tmin at the current speed V1 of the host vehicle 61, the current speed V1 of the host vehicle is maintained until deceleration of the other vehicle 63 is detected or until a second vehicle speed maintenance time Tm2 elapses. By maintaining the speed V1 of the host vehicle 61 in this way, it becomes possible to suppress unnecessary acceleration and deceleration of the host vehicle 61 after the interruption detection, so that the comfort of the driver can be further improved.

[0102] In addition, in the vehicle control device 1 according to the present embodiment, when an interruption by another vehicle 63 is detected during constant-speed driving at a set vehicle speed, if the speed V3 of the other vehicle 63 is higher than the speed V1 of the host vehicle 61, even if the actual inter-vehicle time Tc with the other vehicle 63 is equal to or less than the set inter-vehicle time Tps' with the preceding vehicle 62, the switching to the set inter-vehicle time Tps" that is equal to or less than the first threshold value TH1 while maintaining the set inter-vehicle time Tps' is aborted. Thereby, it becomes possible to maintain a sufficient set inter-vehicle time with respect to the interrupting other vehicle 63, and thus the comfort of the driver can be further enhanced. Further, when an interruption by another vehicle 63 is detected during constant-speed driving, if the speed V3 of the other vehicle 63 is higher than the speed V1 of the host vehicle 61 and the actual inter-vehicle time Tc with the other vehicle 63 exceeds the shortest inter-vehicle time Tmin at the current speed V1 of the host vehicle 61, the current speed V1 of the host vehicle is maintained until the deceleration of the other vehicle 63 is detected or until the second vehicle speed maintenance time Tm2 elapses. By maintaining the current speed V1 of the host vehicle 61 under such circumstances during constant-speed driving, it becomes possible to suppress unnecessary deceleration for ensuring the set inter-vehicle time with the other vehicle 63, and thus the comfort of the driver can be further improved.

[0103] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications and changes are possible based on the technical idea of the present invention. For example, in the above-described embodiment, an example in which the set inter-vehicle time with the preceding vehicle is divided into three levels of "short", "medium", and "long" has been shown. However, the set inter-vehicle time with the preceding vehicle in the present invention is not limited to the above example, and it may be divided into two levels or four levels or more. The present invention is also effective for an ACC in which the number of levels of the set inter-vehicle time is increased so that the set inter-vehicle time is regarded as a substantially continuous value.

[0104] In the above-described embodiment, an example was explained in which after predicting an intrusion by another vehicle, the intrusion by the other vehicle is actually detected and the set inter-vehicle time with the preceding vehicle is switched. However, without predicting the intrusion by the other vehicle, only the detection of the intrusion by the other vehicle is performed, and the set inter-vehicle time with the preceding vehicle may be switched in the same concept as in the case of the above-described embodiment, and the running control by ACC may be performed.

Explanation of Signs

[0105] 1…Control device of vehicle 10…Peripheral situation detection unit 11…Millimeter-wave radar 12…Camera sensor 13…Blind Spot Monitor (BSM) 20…Vehicle state detection unit 21…Vehicle speed sensor 22…Acceleration sensor 23…Brake sensor 24…Steering angle sensor 25…Accelerator opening sensor 26…Travel direction detector 27…Direction indicator 30…ACC controller 31…Obstacle recognition unit 32…Preceding vehicle recognition unit 33…Running lane recognition unit 34…Intruding vehicle recognition unit (intrusion prediction means, intrusion detection means) 35…Peripheral situation recognition unit 36…Running control unit (Adaptive Cruise Control means) 37…Display control unit 40…Vehicle control unit 41…Engine / motor controller 42…Brake controller 43…Anti-skid device 44…Transmission controller 50…Display unit 51…Set vehicle speed display area 52…Set inter-vehicle display area 53…Controlled vehicle speed display area 54…Controlled inter-vehicle display area 55… Peripheral situation display area 61… Own vehicle 62… Leading vehicle 63… Other vehicle (cut-in vehicle) DS, DM, DL… Inter-vehicle distance from leading vehicle Tc… Actual inter-vehicle time with other vehicle TH1… First threshold value TH2… Second threshold value Tm1… First vehicle speed maintenance time Tm2… Second vehicle speed maintenance time Tmin… Shortest inter-vehicle time Tp… Actual inter-vehicle time with leading vehicle Tps, Tps’, Tps”… Set inter-vehicle time with leading vehicle V1… Speed of own vehicle V3… Speed of other vehicle

Claims

1. An adaptive cruise control means for driving at a constant speed at a set vehicle speed or for following a preceding vehicle while maintaining a set inter-vehicle time; A vehicle control device including: an interruption detection means for detecting an interruption of another vehicle in front of the host vehicle, The adaptive cruise control means is configured to, when the cut-in detection means detects an cut-in by another vehicle, switch the set inter-vehicle time to a shorter set inter-vehicle time if the actual inter-vehicle time with the other vehicle is equal to or less than the set inter-vehicle time with the preceding vehicle.

2. The vehicle control device according to claim 1, The adaptive cruise control means is configured to return the set inter-vehicle time with the preceding vehicle to the state before the cut-in detection means detects the cut-in of another vehicle after a predetermined waiting time has elapsed since the cut-in detection means detects the cut-in of another vehicle, or after it is determined that the other vehicle is traveling at a constant speed.

3. The vehicle control device according to claim 1, The adaptive cruise control means is configured to, when the cut-in detection means detects the cut-in of another vehicle during the following driving, if the speed of the other vehicle is faster than the speed of the host vehicle and the actual vehicle-to-vehicle distance between the other vehicle exceeds the set vehicle-to-vehicle distance between the host vehicle, maintain the current speed of the host vehicle until deceleration of the other vehicle is detected or until a first vehicle speed maintenance time has elapsed, while, when the speed of the other vehicle is faster than the speed of the host vehicle, the actual vehicle-to-vehicle distance between the other vehicle is equal to or less than the set vehicle-to-vehicle distance between the host vehicle, and the actual vehicle-to-vehicle distance between the other vehicle exceeds the shortest vehicle-to-vehicle distance at the current speed of the host vehicle, maintain the current speed of the host vehicle until deceleration of the other vehicle is detected or until a second vehicle speed maintenance time shorter than the first vehicle speed maintenance time has elapsed.

4. The vehicle control device according to claim 3, The adaptive cruise control means is configured to, when the cut-in detection means detects the cut-in of another vehicle during the constant speed traveling, if the speed of the other vehicle is faster than the speed of the host vehicle, maintain the set inter-vehicle time even if the actual inter-vehicle time with the other vehicle is less than or equal to the set inter-vehicle time with the preceding vehicle, and to maintain the current speed of the host vehicle until deceleration of the other vehicle is detected or until the second vehicle speed maintenance time has elapsed if the speed of the other vehicle is faster than the speed of the host vehicle and the actual inter-vehicle time with the other vehicle exceeds the shortest inter-vehicle time at the current speed of the host vehicle.

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