Driving assistance system

Abstract

Effectively suppresses the feeling of anxiety in users. [Solution] A driving control device is configured to selectively set at least two set distances, including a first set distance and a second set distance shorter than the first set distance, and is capable of performing follow-up driving control to make the vehicle follow a preceding vehicle based on the set distances. During the implementation of follow-up driving control based on the first set distance, a first collision buffer time is calculated, which is the remaining time until the vehicle collides with the preceding vehicle, and a second collision buffer time is calculated, which is the remaining time until the vehicle collides with the preceding vehicle if follow-up driving control is performed based on the second set distance. If the first collision buffer time is shorter than the second collision buffer time, at least one of the deceleration and deceleration start timing of the follow-up driving control based on the first set distance is changed.

Description

[Technical Field]

[0001] This disclosure relates to a driving assistance system. [Background technology]

[0002] A driving assistance device capable of performing Adaptive Cruise Control (ACC), which causes the vehicle to follow a preceding vehicle based on a set distance between vehicles, is known (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2007-001383 [Overview of the project]

[0004] In ACC (Adaptive Cruise Control), there are systems configured to allow users to select from multiple set distances with different values ​​according to their preferences. In such systems, in order to avoid causing anxiety to the user while ACC is running, it is desirable to have driving control that takes into account the time to collision (TTC). Here, TTC is the remaining time until the vehicle collides with the preceding vehicle, assuming that the vehicle is traveling at its current speed, and can be calculated by dividing the relative distance between the vehicle and the preceding vehicle by the relative speed.

[0005] One example of driving control that takes TTC into account is that when a relatively long set following distance is selected by the user, the vehicle's deceleration and other actions are controlled so that the TTC is longer compared to when a relatively short set following distance is selected. However, even when a relatively long set following distance is selected, the TTC may temporarily shorten depending on the driving conditions, such as when the preceding vehicle suddenly decelerates. In such cases, even though the user has selected a relatively long set following distance, the shortening of the distance to the preceding vehicle may cause the user to feel uneasy.

[0006] This disclosure is made to solve the above-mentioned problems and aims to effectively suppress the feeling of anxiety that users may experience when they select a relatively long following distance.

[0007] The technology disclosed herein is A driving control device is configured to selectively set at least two or more set distances, including a first set distance and a second set distance shorter than the first set distance, and is capable of performing follow-driving control to make its own vehicle follow a preceding vehicle based on the set distances, During the execution of the follow-up driving control based on the first set distance, a first collision buffer time is calculated, which is the remaining time until the vehicle collides with the preceding vehicle. A second collision buffer time is also calculated, which is the remaining time until the vehicle collides with the preceding vehicle, assuming that the follow-up driving control is performed based on the second set distance. The present invention is characterized in that, when the first collision margin time is shorter than the second collision margin time, at least one of the deceleration and deceleration start timing of the follow-up driving control based on the first set distance between vehicles is changed. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing the hardware configuration of the vehicle according to this embodiment. [Figure 2]This is a schematic diagram showing the software configuration of the driving assistance system according to this embodiment. [Figure 3] This is a flowchart illustrating the deceleration control routine according to this embodiment. [Modes for carrying out the invention]

[0009] The driving support device according to this embodiment will be described below with reference to the drawings.

[0010] [Hardware configuration] Figure 1 is a schematic diagram showing the hardware configuration of vehicle VH according to this embodiment. Hereinafter, vehicle VH may be referred to as "our vehicle" when it is necessary to distinguish it from other vehicles, etc.

[0011] Vehicle VH has an ECU (Electronic Control Unit) 10. The ECU 10 includes a CPU (Central Processing Unit) 11, ROM (Read Only Memory) 12, RAM (Random Access Memory) 13, and an interface device 14, etc. The CPU 11 is a processor that executes various programs stored in the ROM 12. The ROM 12 is a non-volatile memory that stores data necessary for the CPU 11 to execute various programs. The RAM 13 is a volatile memory that provides a work area that is expanded when various programs are executed by the CPU 11. The interface device 14 is a communication device for communicating with external devices.

[0012] The ECU10 is the central device that provides driving assistance such as ACC. Driving assistance is a concept that includes autonomous driving. The ECU10 is connected to the drive unit 20, steering unit 21, braking unit 22, internal sensor device 30, external sensor device 40, ACC control unit 70, etc., in a communication manner.

[0013] The drive unit 20 generates a driving force that is transmitted to the drive wheels of the vehicle VH. Examples of the drive unit 20 include an electric motor and an engine. The vehicle VH may be a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a fuel cell electric vehicle (FCEV), a battery electric vehicle (BEV), or an engine-powered vehicle. The steering unit 21 applies steering force to the wheels of the vehicle VH. The braking unit 22 applies braking force to the wheels of the vehicle VH.

[0014] The internal sensor device 30 consists of sensors that acquire the state of the vehicle's VH. The internal sensor device 30 includes a wheel speed sensor 31, an accelerator sensor 32, a brake sensor 33, a steering angle sensor 34, a yaw rate sensor 35, a longitudinal acceleration sensor 36, and the like.

[0015] The wheel speed sensor 31 detects the vehicle speed (vehicle speed) of the vehicle VH. The accelerator sensor 32 detects the amount of accelerator pedal operation by the driver (not shown). The brake sensor 33 detects the amount of brake pedal operation by the driver (not shown). The steering angle sensor 34 detects the rotation angle (steering angle) of the steering wheel or steering shaft (not shown). The yaw rate sensor 35 detects the yaw rate of the vehicle VH. The longitudinal acceleration sensor 36 detects the longitudinal acceleration of the vehicle VH. The internal sensor device 30 transmits the state of the vehicle VH detected by each sensor 31 to 36 to the ECU 10 at a predetermined interval.

[0016] The external sensor device 40 consists of sensors that recognize object information relating to objects around the vehicle VH. The external sensor device 40 includes a radar sensor 41, a camera sensor 42, etc. Here, object information can be, for example, surrounding vehicles, road markings, road signs, etc.

[0017] The radar sensor 41 detects targets present around the vehicle VH. The radar sensor 41 includes a millimeter-wave radar and / or a lidar. The millimeter-wave radar emits radio waves in the millimeter-wave band and receives millimeter waves reflected by targets within its radiation range. The millimeter-wave radar acquires the relative distance and relative speed between the vehicle VH and the target based on the phase difference between the transmitted millimeter waves and the received reflected waves, the attenuation level of the reflected waves, and the time from the transmission of the millimeter waves to the reception of the reflected waves. The lidar sequentially scans pulsed laser light with a wavelength shorter than millimeter waves in multiple directions and receives the reflected light reflected by targets to acquire the shape of targets detected around the vehicle VH, the relative distance and relative speed between the vehicle VH and the targets.

[0018] The camera sensor 42 captures images of the area around the vehicle VH and processes the captured image data to acquire target information around the vehicle VH. For example, a digital camera with an image sensor such as a CMOS or CCD can be used as the camera sensor 42. The target information includes the type of target detected around the vehicle VH, the relative distance between the vehicle VH and the target, and the relative speed. The type of target can be recognized, for example, by machine learning such as pattern matching.

[0019] The external sensor device 40 transmits the acquired target information to the ECU 10 at predetermined intervals. The external sensor device 40 does not necessarily need to include both the radar sensor 41 and the camera sensor 42; for example, it may include only the radar sensor 41 or only the camera sensor 42.

[0020] The ACC control unit 70 consists of switches operated by the driver to configure various settings for the ACC. The ACC control unit 70 includes, for example, a start switch 71 for selecting whether to start or stop the ACC, a setting switch 72 for setting the ACC's set vehicle speed Vt and set following distance Dt (or set following time), a cancel switch 73 for temporarily disabling the running ACC, and a resume switch 74 for restarting the ACC. Some of these switches (for example, the cancel switch 73 and the resume switch 74) may be integrated into a single switch.

[0021] [Software Configuration] Figure 2 is a schematic diagram showing the software configuration of the driving support system according to this embodiment.

[0022] As shown in Figure 2, the ECU 10 includes an ACC processing unit 100, a deceleration control unit 110, and other functional elements. Each of these functional elements 100 and 110 is realized when the CPU 11 of the ECU 10 reads a program stored in the ROM 12 into the RAM 13 and executes it. Note that all or part of each of the functional elements 100 and 110 may be installed in another ECU separate from the ECU 10, or in an information processing device of a facility (such as a management center) that can communicate with the vehicle VH.

[0023] The ACC processing unit 100 executes ACC based on the set vehicle speed Vt or the set distance between vehicles Dt. As ACC itself is well known, it will be briefly explained below. ACC includes two types of control: constant speed driving control and follow driving control. Constant speed driving control is a control that drives the vehicle VH at a constant speed according to the set vehicle speed Vt without requiring the driver to operate the accelerator or brake. Follow driving control is a control that makes the vehicle VH follow the preceding vehicle so that the actual distance Da between the preceding vehicle and the vehicle VH becomes the set distance between vehicles Dt, without requiring the driver to operate the accelerator or brake. The preceding vehicle is a vehicle located in the area in front of the vehicle VH and directly in front of the vehicle VH.

[0024] When the activation switch 71 of the ACC operation unit 70 is turned ON, the ACC processing unit 100 searches for a preceding vehicle to follow based on the detection results of the external sensor device 40. If no preceding vehicle exists, the ACC processing unit 100 performs constant speed driving control. In this case, the ACC processing unit 100 controls the operation of the drive unit 20 and the braking unit 22 based on a target deceleration or target acceleration determined from the difference between the actual vehicle speed Va and the set vehicle speed Vt. The actual vehicle speed Va can be obtained based on the detection results of the wheel speed sensor 31.

[0025] On the other hand, the ACC processing unit 100 performs follow-up driving control if a preceding vehicle exists. In this case, the ACC processing unit 100 controls the operation of the drive unit 20 and the brake unit 22 based on a target deceleration or target acceleration determined from the deviation between the actual distance Da and the set distance Dt. The actual distance Da between the vehicle VH and the preceding vehicle can be obtained based on the detection results of the external sensor device 40. The target deceleration or target acceleration can be set, for example, by referring to a target acceleration / deceleration setting map (not shown) based on the deviation between the actual distance Da and the set distance Dt. The timing at which the vehicle VH starts to decelerate or accelerate can be set, for example, by referring to a start timing setting map (not shown) based on the target deceleration or target acceleration. These target acceleration / deceleration setting maps and start timing setting maps can be stored in the storage unit of the ECU 10 (for example, ROM 12).

[0026] The driving support device of this embodiment is configured to allow the user to select at least two or more set intervals Dt in response to the operation of the setting switch 72. The number of selectable intervals Dt may be, for example, two stages: long distance and short distance, or three stages: long distance, medium distance and short distance, or four or more stages. For convenience, in the following description, the number of selectable intervals Dt will be described as two stages: a relatively long distance and a relatively short distance.

[0027] Furthermore, in the following explanation, the long-distance set following distance is referred to as "First set following distance Dt _L", and the short-distance set inter-vehicle distance is referred to as "second set inter-vehicle distance Dt _S " (Dt _L >Dt _S ). Further, the ACC processing unit 100 refers to the follow-up travel control executed based on the first set inter-vehicle distance Dt _L as "first follow-up travel control", and refers to the follow-up travel control executed based on the second set inter-vehicle distance Dt _S as "second follow-up travel control". Further, the ACC processing unit 100 refers to the target deceleration set by referring to the target acceleration / deceleration setting map based on the deviation between the actual inter-vehicle distance Da and the first set inter-vehicle distance Dt during execution of the first follow-up travel control as "first target deceleration ΔGe". Further, the deceleration start timing set by the ACC processing unit 100 by referring to the start timing setting map based on the first target deceleration ΔGe is referred to as "first deceleration start timing Tm". _L

[0028] Now, assume that a preceding vehicle suddenly decelerates during execution of follow-up travel control. In such a situation, if the deceleration start timing of the host vehicle VH is delayed, or the deceleration of the host vehicle VH is insufficient, the TTC during execution of the first follow-up travel control (hereinafter referred to as first TTC _L ) may temporarily become shorter than the TTC on the assumption that the second follow-up travel control is being executed (hereinafter referred to as second TTC _S ) (the first TTC _L <the second TTC _S ). When the first TTC _L becomes shorter than the second TTC _S , even though the user has selected the first set inter-vehicle distance Dt _L , the inter-vehicle distance between the host vehicle VH and the preceding vehicle becomes short, which causes a problem of giving the user a sense of anxiety. The deceleration control unit 110 executes deceleration control that prevents the first TTC _L from becoming shorter than the second TTC _S during execution of the first follow-up travel control. Hereinafter, the details of the deceleration control will be described.

[0029] The deceleration control unit 110, during execution of the first follow-up travel control, performs processing based on the first TTC _L ​This is calculated repeatedly at a predetermined interval. The first TTC _L This can be determined by dividing the actual distance Da between the vehicle VH and the preceding vehicle, which is obtained based on the detection results of the external sensor device 40, by the relative speed Vr (first TTC _L (=Da / Vr). Also, the deceleration control unit 110 performs the second TTC during the execution of the first follow-me driving control. _S This is repeated at a predetermined interval. Second TTC _S This can be determined by dividing the virtual inter-vehicle distance Ds by the relative speed Vr obtained based on the detection results of the external sensor device 40 (second TTC _S (=Ds / Vr). The virtual inter-vehicle distance Ds is calculated by subtracting the first set inter-vehicle distance Dt from the actual inter-vehicle distance Da, which is obtained based on the detection results of the external sensor device 40. _L and the second set distance between vehicles Dt _S This can be calculated by subtracting the difference ΔD from (Ds = Da - ΔD = Da - Dt _L -Dt _S ).

[0030] The deceleration control unit 110 controls the first TTC _L The second TTC _S If the value becomes shorter than the value obtained by adding a predetermined constant TH to the value obtained by the ACC processing unit 100, the ACC processing unit 100 acquires the first target deceleration ΔGe and the first deceleration start timing Tm. The constant TH may be 0, a fixed value other than 0, or a variable value corresponding to the vehicle speed V, etc. The deceleration control unit 110 also calculates the relative speed between the vehicle VH and the preceding vehicle after deceleration (hereinafter referred to as the estimated relative speed after deceleration Vrs) when the vehicle VH decelerates based on the first target deceleration ΔGe. The estimated relative speed after deceleration Vrs can be obtained by subtracting the value obtained by multiplying the first target deceleration ΔGe by a predetermined sampling time ts from the relative speed Vr obtained based on the detection result of the external sensor device 40 (Vrs = Vr - ΔGe × ts).

[0031] The deceleration control unit 110 calculates the estimated relative speed Vrs after deceleration, and then divides the actual distance Da obtained based on the detection results of the external sensor device 40 by the estimated relative speed Vrs after deceleration, thereby determining the TTC after deceleration if the first follow-me driving control is continued (hereinafter referred to as the first estimated TTC after deceleration). _Lg The calculation of (the first estimated TTC after deceleration) is performed. _Lg =Da / Vrs). Furthermore, the deceleration control unit 110 divides the above-mentioned virtual inter-vehicle distance Ds by the estimated relative speed Vrs after deceleration to determine the TTC after deceleration (hereinafter referred to as the second estimated TTC after deceleration) assuming that the second follow-up driving control has been executed. _Sg (The second estimated TTC after deceleration) is calculated. _Sg =Ds / Vrs).

[0032] The deceleration control unit 110 calculates the first estimated TTC after deceleration. _Lg However, the estimated TTC after the second deceleration _Sg If the value is greater than or equal to the value obtained by adding a constant TH (first estimated TTC after deceleration) _Lg ≥ Estimated TTC after the second deceleration _Sg (+TH), the first deceleration control is executed to advance the deceleration start timing of the vehicle VH by subtracting a predetermined subtraction time Td from the first deceleration start timing Tm. The subtraction time Td may be a fixed value or a variable value. If it is a variable value, for example, the first TTC _L and the second TTC _S The difference from, or the estimated TTC after the first deceleration. _Lg and the estimated TTC after the second deceleration _Sg The larger the difference, the longer the subtraction time Td should be. In other words, the timing of when deceleration should start should be brought forward significantly.

[0033] In this way, by advancing the first deceleration start timing Tm, which initiates deceleration in the first follow-me driving control, the first TTC is executed during the execution of the first follow-me driving control. _L The second TTC _SThis makes it possible to effectively suppress the deceleration from becoming shorter than the specified time. Furthermore, by advancing only the first deceleration start timing Tm and maintaining the deceleration of the vehicle VH at the first target deceleration ΔGe set by the ACC processing unit 100, it becomes possible to effectively suppress the occurrence of excessive deceleration in the vehicle VH.

[0034] Meanwhile, the deceleration control unit 110 calculates the first estimated TTC after deceleration. _Lg However, the estimated TTC after the second deceleration _Sg If the value is shorter than the value obtained by adding the constant TH to (TTC) _Lg <TTC _Sg In addition to the first deceleration control that advances the first deceleration start timing Tm as described above, a second deceleration control is performed that increases the first target deceleration ΔGe by a predetermined increase amount Gp. The increase amount Gp is, for example, the first TTC _L and the second TTC _S The difference from, or the estimated TTC after the first deceleration. _Lg and the estimated TTC after the second deceleration _Sg The larger the difference, the larger the value should be. The increase Gp is ​​the first TTC _L and the second TTC _S The difference from, or the estimated TTC after the first deceleration. _Lg and the estimated TTC after the second deceleration _Sg It may also be set by referring to a map (not shown) based on the difference with the first TTC _L , the second TTC _S Alternatively, it may be calculated using a formula based on the estimated relative velocity Vrs after deceleration, the sampling time ts, etc.

[0035] Thus, the first estimated TTC after deceleration _Lg However, the estimated TTC after the second deceleration _Sg If the value is shorter than the value obtained by adding a constant TH to the first deceleration start timing Tm, the first target deceleration ΔGe is increased by an amount Gp while the first deceleration start timing Tm is advanced, thereby correcting the insufficient deceleration, and the first TTC is executed during the execution of the first follow-me driving control. _L The second TTC _S This makes it possible to reliably prevent the time from becoming shorter than that.

[0036] Figure 3 is a flowchart illustrating the deceleration control routine executed by the CPU 11 of the ECU 10. This routine is started, for example, when the ACC is activated by turning on the start switch 71.

[0037] In step S100, the ECU 10 determines whether or not it is currently performing the first follow-me driving control. If it is performing the first follow-me driving control (Yes), the ECU 10 proceeds to the process in step S110. On the other hand, if it is not performing the first follow-me driving control (No), the ECU 10 returns to this routine.

[0038] In step S110, ECU10 sets the first set distance between vehicles Dt _L and the second set distance between vehicles Dt _S The difference ΔD(=Dt) _L -Dt _S ) is calculated. Next, in step S115, the ECU 10 obtains the actual distance Da and relative speed Vr between its own vehicle VH and the preceding vehicle based on the detection results of the external sensor device 40. Note that the processing in steps S110 and S115 can be performed in any order and may be performed simultaneously.

[0039] In step S120, the ECU10 calculates the first TTC by dividing the actual distance Da by the relative speed Vr. _L (=Da / Vr) is calculated. Also, in step S130, the ECU10 calculates the first set distance Dt from the actual distance Da. _L and the second set distance between vehicles Dt _S By subtracting the difference ΔD from the original distance, the virtual inter-vehicle distance Ds (=Da-ΔD) is calculated, and by dividing the virtual inter-vehicle distance Ds by the relative speed Vr, the second TTC is calculated. _S The calculation (=Ds / Vr) is performed. Note that the processing in steps S120 and S130 can be done in any order and may be done simultaneously.

[0040] In step S140, ECU10 is the first TTC _L The second TTC _S It is determined whether the value obtained by adding a predetermined constant TH to the first TTC is shorter._L The second TTC _S If the value obtained by adding a predetermined constant TH to the value is shorter (Yes), the ECU 10 proceeds to step S150. Meanwhile, the first TTC _L The second TTC _S If the value is not shorter than the value obtained by adding a predetermined constant TH (No), ECU10 returns this routine. In other words, ECU10 performs normal ACC.

[0041] In step S150, the ECU 10 acquires the first target deceleration ΔGe and the first deceleration start timing Tm set by ACC. Next, in step S160, the ECU 10 calculates the estimated relative velocity after deceleration Vrs (=Vr-ΔGe×ts) by subtracting from the relative velocity Vr the value obtained by multiplying the first target deceleration ΔGe by a predetermined sampling time ts.

[0042] In step S170, the ECU 10 calculates the first estimated TTC after deceleration by dividing the actual distance between vehicles Da by the estimated relative speed Vrs after deceleration. _Lg (=Da / Vrs) is calculated. Also, in step S175, the ECU 10 divides the virtual inter-vehicle distance Ds by the estimated relative speed Vrs after deceleration to obtain the second estimated TTC after deceleration. _Sg The calculation (=Ds / Vrs) is performed. Note that the processing in steps S170 and S175 can be done in any order and may be done simultaneously.

[0043] In step S180, the first estimated TTC after deceleration is calculated. _Lg However, the estimated TTC after the second deceleration _Sg Determine whether it is shorter than the value obtained by adding a constant TH to the first estimated TTC after deceleration. _Lg However, the estimated TTC after the second deceleration _Sg If the value is greater than or equal to the value obtained by adding the constant TH (No), the ECU 10 proceeds to step S195, executes the first deceleration control to advance the first deceleration start timing Tm, and then returns to this routine. In other words, it returns to normal ACC. Meanwhile, the estimated TTC after the first deceleration _Lg However, the estimated TTC after the second deceleration _SgIf the value is shorter than the value obtained by adding the constant TH (Yes), the ECU 10 proceeds to step S190 and executes a first deceleration control that advances the first deceleration start timing Tm, as well as a second deceleration control that increases the first target deceleration ΔGe by a predetermined increase amount Gp, and then returns to this routine. In other words, it returns to normal ACC.

[0044] Although the driving support device according to this embodiment has been described above, this disclosure is not limited to the above-described embodiment, and various modifications are possible without departing from the purpose of this disclosure.

[0045] [Example 1] For example, the subtraction time Td to advance the first deceleration start timing Tm, and the increase amount Gp to increase the first target deceleration ΔGe, are determined in advance by simulation, etc., for the first TTC _L The second TTC _S It may also be set by determining a value that prevents it from becoming shorter than the given value. In this case, the first TTC is set in ECU10. _L and the second TTC _S This eliminates the need for comparison, allowing for an efficient reduction in the computational load on the ECU10.

[0046] [Differentiation 2] For example, the deceleration conditions for the first follow-me driving control and the second follow-me driving control are defined, and the driver's state is monitored using a driver monitoring camera or the like. When it is determined, based on facial images captured by the driver monitoring camera, that the driver feels more uneasy about the second follow-me driving control than the first follow-me driving control under the same deceleration conditions, the deceleration settings for the follow-me driving control may be modified, and the modified settings may be stored in the ECU 10.

[0047] [Difference 3] For example, in Modification Example 2, while the first TTC is being executed in a certain vehicle, _L The second TTC _SWhen it is detected that the time has become shorter than the above, the occurrence condition is specified and transmitted to a server such as a management center. The server side may modify the deceleration setting of the following travel control, and transmit the modified setting to other traveling vehicles from the server for reflection. Alternatively, the sensor values (relative distance, relative speed, etc.) of each vehicle may be transmitted to the server, and the server side may perform the first TTC _L and the second TTC _S comparison, setting change, and the like may be performed.

[0048] [Modification 4] For example, deceleration conditions are stored for each setting of the first set inter-vehicle distance Dt _L and the second set inter-vehicle distance Dt _S , and the respective first TTC _L and second TTC _S are calculated. The calculated first TTC _L and second TTC _S are compared, and the deceleration setting of the following travel control may be modified by extracting the occurrence condition that the first TTC _L has become shorter than the second TTC _S .

[0049] [Modification 5] For example, a condition in which the driver hardly feels that the first TTC _L has become shorter than the second TTC _S (for example, a condition in which the TTC is larger than a far-side determination threshold) is defined, and by applying braking force to the vehicle VH when the condition is satisfied, it is possible to suppress the first TTC _L from becoming shorter than a predetermined value. In other words, during execution of the first following travel control, when the preceding vehicle is present far away from the host vehicle VH, the relative speed is decreased, and even if the following travel control is operated spontaneously, the first TTC _L can be prevented from becoming shorter than the second TTC _S .

Claims

[Claim 1] A driving control device is configured to selectively set at least two or more set distances, including a first set distance and a second set distance shorter than the first set distance, and is capable of performing follow-driving control to make its own vehicle follow a preceding vehicle based on the set distances, During the execution of the follow-up driving control based on the first set distance, a first collision buffer time is calculated, which is the remaining time until the vehicle collides with the preceding vehicle. A second collision buffer time is also calculated, which is the remaining time until the vehicle collides with the preceding vehicle, assuming that the follow-up driving control is performed based on the second set distance. If the first collision margin time is shorter than the second collision margin time, at least one of the deceleration and deceleration start timing of the follow-up driving control based on the first set distance between vehicles is changed. A driving support device characterized by the following features.

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