JP6158523B2 - Inter-vehicle distance control device - Google Patents

Description

  The present invention relates to an inter-vehicle distance control device that detects a preceding vehicle ahead of the host vehicle and controls an inter-vehicle distance between the preceding vehicle and the host vehicle.

  An inter-vehicle distance control device that detects an inter-vehicle distance from a preceding vehicle and automatically controls the inter-vehicle distance and speed according to the vehicle speed of the host vehicle is known. In such an inter-vehicle distance control device, when another vehicle is interrupted or the preceding vehicle leaves while controlling the inter-vehicle distance from the preceding vehicle, the preceding vehicle to be followed is switched. Since the vehicle speed and the inter-vehicle distance of the preceding vehicle change, the situation is likely to cause acceleration / deceleration. For this reason, conventionally, a technique for appropriately continuing the inter-vehicle distance control in response to a vehicle interruption or separation has been considered (for example, see Patent Documents 1 to 3).

  FIG. 10A is an example of a diagram illustrating the technique of Patent Document 1. FIG. Patent Document 1 describes a technique for switching a preceding vehicle that travels early by monitoring the lateral speed of another vehicle that interrupts or leaves.

  FIG. 10B is an example of a diagram illustrating the technique of Patent Document 2. Patent Document 2 discloses a technique for suppressing unnecessary steering by limiting the steering amount of the host vehicle in a transient state of lane change.

  FIG. 10C is an example of a diagram illustrating the technique of Patent Document 3. In Patent Document 3, an approach of a vehicle to a travel region that is undesirable for the driver is predicted based on a travel state of the vehicle, and an output is adjusted so as to avoid a vehicle entering the travel region that is undesirable for the driver (early). Brake control) technology is disclosed.

JP 2004-58920 A JP 2007-176290 A JP 2010-274887

  However, in Patent Documents 1 to 3, there is a problem that the case where the interrupted vehicle moves in a direction away from the same lane with respect to the own vehicle is not considered.

  FIG. 10D is a diagram schematically illustrating a case where a vehicle that has moved in the direction of moving away from the same lane with respect to the host vehicle moves. The vehicle speed of each vehicle is Va = Vb <Vc. When the other vehicle C interrupts, the own vehicle A follows the other vehicle C, and therefore executes acceleration control of Va → Vc. However, if the other vehicle C leaves immediately after the acceleration of the host vehicle, the host vehicle A resumes following the preceding vehicle B, and therefore executes deceleration control of Va → Vb. That is, unnecessary control such as acceleration / deceleration is executed in a short time.

  In view of the above problems, an object of the present invention is to provide an inter-vehicle distance control device that suppresses unnecessary control when an interrupted vehicle moves in a direction away from the same lane with respect to the host vehicle.

The present invention is an inter-vehicle distance control device that detects the preceding vehicle ahead of the host vehicle and controls the inter-vehicle distance between the preceding vehicle and the host vehicle, and detects the relative speed to the preceding vehicle and the distance from the host vehicle. Acceleration / deceleration determination for determining acceleration or deceleration for controlling the inter-vehicle distance to the preceding vehicle based on the relative speed and the distance detected by the vehicle speed distance detection unit and the vehicle speed distance detection unit. And when another preceding vehicle interrupts between the preceding vehicle and the host vehicle in a state of following the preceding vehicle at the acceleration or the deceleration determined by the acceleration / deceleration determining unit, An inter-vehicle time calculating means for calculating an inter-vehicle time between the preceding vehicle and the other preceding vehicle, and when it is determined that the other preceding vehicle moves away from the own vehicle because the inter-vehicle time is smaller than a threshold value , interrupted. With the other preceding vehicle The acceleration determined by the acceleration / deceleration determining means for controlling the inter-vehicle distance to the target inter-vehicle distance is determined based on the relative speed and the distance detected with respect to the other preceding vehicle interrupted by the vehicle speed distance detecting means. Acceleration / deceleration control means that suppresses acceleration more than the acceleration that is generated, and the acceleration / deceleration control means suppresses acceleration most immediately immediately after the other preceding vehicle interrupts, and suppresses acceleration over time immediately after the interruption. The control for reducing the acceleration is terminated after a certain amount of time shorter than the inter-vehicle time has elapsed .

  It is possible to provide an inter-vehicle distance control device that suppresses unnecessary control when an interrupted vehicle moves in a direction away from the host vehicle on the same lane.

It is an example of the figure explaining the schematic characteristic of the inter-vehicle distance control apparatus of this embodiment. It is an example of the schematic block diagram of a vehicle distance control apparatus. It is an example of the flowchart figure which shows the schematic procedure of inter-vehicle distance control. It is an example of a functional block diagram of the inter-vehicle control ECU. It is an example of the flowchart figure which shows the procedure which suppresses target acceleration. It is an example of the figure explaining suppression of target acceleration. It is an example of the figure explaining the control example of inter-vehicle control ECU with respect to the behavior of the other vehicle C to interrupt. It is an example of the figure explaining another vehicle situation where interruption and secession may arise. It is an example of the figure explaining another vehicle situation where interruption and secession may arise. It is an example of the figure explaining the technique of a prior art.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited to this embodiment.

A schematic feature of the inter-vehicle distance control apparatus according to the present embodiment will be described with reference to FIG. The inter-vehicle distance control device determines whether or not acceleration is necessary using the inter-vehicle time Tbc between the preceding vehicle B and the other vehicle C when the other vehicle C has interrupted in front of the host vehicle.
Tbc = (Db−Dc) / (Vb−Vc) (1)
Db: Distance between the host vehicle A and the preceding vehicle B Dc: Distance between the host vehicle A and the other vehicle C If the inter-vehicle time Tbc is equal to or greater than the threshold value, it can be estimated that the other vehicle C is unlikely to leave immediately. Further, even if the other vehicle C leaves after the host vehicle A accelerates, it can be estimated that the distance (inter-vehicle time) from the host vehicle A to the preceding vehicle B is long, and the deceleration for traveling following the preceding vehicle B is also possible. It can be expected to be relatively moderate. For this reason, if the inter-vehicle time Tbc is larger than the threshold value, the conventional inter-vehicle distance is performed for the other vehicle C.

  On the other hand, if the inter-vehicle time Tbc is less than the threshold value, it can be estimated that there is a high possibility that the other vehicle C will immediately leave. Further, when the other vehicle C leaves after the host vehicle A accelerates, it can be estimated that the distance (inter-vehicle time) from the host vehicle A to the preceding vehicle B is short, and the deceleration for traveling following the preceding vehicle B is relatively high. It is considered large. Therefore, when the inter-vehicle time Tbc is less than the threshold, the inter-vehicle distance control device suppresses the target acceleration. As a result, even if the vehicle follows the other vehicle C, the vehicle speed of the host vehicle A becomes difficult to increase, and deceleration after leaving can be suppressed.

  Therefore, by comparing the inter-vehicle time Tbc with the threshold value and reducing the acceleration, unnecessary control can be suppressed when the interrupted other vehicle C moves in the direction away from the own vehicle A in the same lane. That is, the necessity for changing the acceleration / deceleration control can be determined.

  Further, if the target acceleration is limited to zero when the inter-vehicle time Tbc is less than the threshold value, the host vehicle A does not accelerate, so unnecessary control can be further suppressed. That is, the necessity for acceleration / deceleration control can be determined.

[Configuration example]
FIG. 2 is an example of a schematic configuration diagram of the inter-vehicle distance control device. The general inter-vehicle distance control of the inter-vehicle distance control device 100 is as follows. The inter-vehicle distance control device 100 may be called ACC (Adaptive Cruise Control). Further, in the present embodiment, the term “inter-vehicle distance control” and the term “following traveling” are used without any particular distinction.
I. A leading vehicle is detected by a radar or the like. When the preceding vehicle is detected, the vehicle travels so that the distance from the preceding vehicle detected by the radar becomes the target inter-vehicle distance corresponding to the vehicle speed.
II. When the preceding vehicle is no longer detected, the vehicle travels at a constant speed at the vehicle speed set by the driver.

  Further, the inter-vehicle distance control device 100 that enables the control of I and II from the low speed range to the stop time may be referred to as “full vehicle speed range constant speed travel / inter-vehicle distance control device (or full vehicle speed ACC)”.

The full vehicle speed range constant speed travel / inter-vehicle distance control device further includes the following functions.
III. When the preceding vehicle stops, the vehicle is stopped while maintaining an appropriate inter-vehicle distance.
IV. When the preceding vehicle resumes traveling, the following traveling is started while maintaining the inter-vehicle distance corresponding to the vehicle speed.

  The inter-vehicle distance control device 100 of the present embodiment can perform the above control even in a low speed range. Therefore, unnecessary deceleration described below can be reduced without distinguishing between ACC and full vehicle speed ACC.

  The inter-vehicle distance control is performed by the inter-vehicle control ECU (Electronic Control Unit) 13 cooperating with the sensor unit 12, the engine ECU 14, the skid control ECU 15, and the like. The sensor unit 12, the inter-vehicle control ECU 13, the engine ECU 14, and the skid control ECU 15 are communicably connected via an in-vehicle network such as a CAN (Controller Area Network) or a dedicated line. The inter-vehicle control ECU 13 has a cruise control switch 11, the engine ECU 14 has a transmission 16, a throttle motor 17, a throttle position sensor 18, and the skid control ECU 15 has a wheel speed sensor 19 and a brake ACT (actuator) 20, which are dedicated lines such as serial communication. Connected with.

  Each ECU is an information processing device equipped with a microcomputer, a power source, a wire harness interface, and the like. The microcomputer has a known configuration including a CPU, a ROM, a RAM, a nonvolatile memory, an I / O, a CAN communication device, and the like. The correspondence between the ECUs and the functions of the ECUs is not fixed. For example, the engine ECU 14 can have the functions of the inter-vehicle control ECU 13, and the illustrated configuration is merely an example.

  The sensor unit 12 includes a radar sensor 21 and a camera sensor 22. In any case, it is possible to detect at least the distance from the preceding vehicle, and it is sufficient to have at least one of them. The radar sensor 21 is disposed at the center of the front of the vehicle such as the front grille of the vehicle, and emits millimeter waves at a predetermined angle (for example, 10 degrees left and right with the front as the center). Receives millimeter waves reflected by an existing object. The radar sensor 21 is, for example, an FMCW (Frequency Modulated Continuous Wave) radar or a pulse radar. The radar sensor 21 generates a beat signal for each reception antenna by mixing the transmission signal and the reception signal with a mixer. The time from when the transmission signal is transmitted until the reception signal is received is proportional to the distance to the object, and the frequency of the beat signal is shifted by the relative speed. Therefore, the distance and relative speed (= Vb−Va. The relative speed at which the distance becomes longer is positive and the relative speed at which the distance approaches is negative) can be obtained by, for example, FFT analysis of the beat signal. The radar sensor 21 can also detect the lateral position x (azimuth θ) of the obstacle by MUSIC (Multiple Signal Classification) analysis or DBF (Digital Beam Forming) processing.

  The camera sensor 22 may be a monocular camera or a stereo camera, but is preferably a stereo camera. For example, the camera sensor 22 is arranged on the rearview mirror with the optical axis facing the front of the vehicle. In the case of a stereo camera, pre-processing is performed to remove lens distortion, optical axis deviation, focal length deviation, imaging element distortion, and the like on frames (image data) captured by each camera using calibration data prepared in advance. As a result, the frames of the two cameras have only a difference corresponding to parallax. The stereo camera evaluates the correlation between the left and right image data by a method such as block matching, and uses the parallax generated in the pixel where the same object is photographed, the focal length f of the lens, and the like for each pixel. Calculate information.

  In the case of a monocular camera, optical flow processing is performed on a plurality of periodically captured image data, the amount of movement of the same object is monitored, and distance information is estimated.

  In addition, after obtaining the distance information or before obtaining the distance information, the camera sensor 22 has HOG (Histograms of Oriented Gradients), Joint HOG, CPF (Co-occurrence Probability Features), CoHOG (Co-occurrence Histograms of Oriented Gradients). The preceding vehicle is recognized by a method such as. The distance to the preceding vehicle can be specified from the distance information of the pixels recognized as the preceding vehicle. Since the camera sensor 22 repeatedly captures a predetermined number (30 to 60) of images per second, the distance of the preceding vehicle can be obtained for each frame. Therefore, the relative speed V is obtained from a change in the distance L between the frames. Further, the lateral position of the preceding vehicle (the center in the vehicle width direction) is made clear from the recognition result.

  Thus, the radar sensor 21 and the camera sensor 22 can obtain equivalent information. The sensor unit 12 periodically transmits the target distance, relative speed, and lateral position (hereinafter referred to as target information) to the inter-vehicle distance control ECU 13.

  The inter-vehicle control ECU 13 transmits the target acceleration (required driving force) to the engine ECU 14 and the skid control ECU 15 based on the target information transmitted from the sensor unit 12, the current vehicle speed, acceleration, and the like. The target acceleration is a positive value or a negative value. If the target acceleration is a positive value, the engine ECU 14 performs acceleration control. If the target acceleration is a negative value and requires braking, the skid control ECU 15 controls the brake ACT 20 to decelerate.

The cruise control switch 11 accepts a driver's operation for the inter-vehicle distance control device 100 and notifies the inter-vehicle control ECU 13. For example, the following operations are possible.
(i) Inter-vehicle distance control ON / OFF
(ii) Switching between inter-vehicle distance control mode and constant speed control mode
(iii) Set the vehicle speed for deceleration, acceleration and constant speed driving
(iv) Setting the inter-vehicle distance (For example, you can select from three types: long, medium, and short, and the inter-vehicle distance is determined according to the vehicle speed for each of long, medium, and short)
In this embodiment, it is assumed that the vehicle operates in the inter-vehicle distance control mode, and when the preceding vehicle is not detected (captured), the vehicle travels at a constant speed with the vehicle speed for constant speed travel in the inter-vehicle distance control mode.

The engine ECU 14 controls the throttle motor 17 while monitoring the throttle opening detected by the throttle position sensor 18. The target acceleration is determined by a procedure as will be described later. For example, the throttle opening is determined from the following equation.
MA _n = MA _n-1 + G × D _dn × T _sk
D _dn = (At _n −ΔV _n )
MA _n : current throttle opening MA _n-1 : previous throttle opening G: control gain T _sk : skip time At _n : target acceleration ΔV _n : vehicle acceleration (actual acceleration)
D _dn : current acceleration deviation Further, the engine ECU 14 determines the necessity of switching of the gear position based on the up-shift line and the down-shift line determined for the vehicle speed and the throttle opening, and if necessary, sends it to the transmission 16. Indicates the gear position. The transmission 16 may be any mechanism such as AT (automatic transmission) or CVT (Continuously Variable Transmission).

  The skid control ECU 15 brakes the vehicle by controlling the opening / closing and opening of the valve of the brake ACT20. The brake ACT 20 controls the acceleration (deceleration) of the vehicle by increasing, maintaining and reducing the wheel cylinder pressure of each wheel by the hydraulic pressure generated by the pump in the working fluid.

(Vehicle distance control)
FIG. 3 is an example of a flowchart showing a schematic procedure of inter-vehicle distance control. The inter-vehicle control ECU 13 periodically repeats the process of FIG. 3 while the cruise control switch 11 is ON.
S10: The inter-vehicle distance control ECU 13 acquires the distance and relative speed from the preceding vehicle from the sensor unit 12, and the vehicle speed of the host vehicle from the wheel speed sensor 19, respectively.
S20: The inter-vehicle control ECU 13 determines the target inter-vehicle distance from the setting (long / medium / short) of the inter-vehicle distance set by the driver and the current vehicle speed.
S30: The inter-vehicle control ECU 13 calculates the target inter-vehicle time by dividing the target inter-vehicle distance by the current vehicle speed, and calculates the inter-vehicle time by dividing the current distance from the preceding vehicle by the vehicle speed. The target inter-vehicle time is the time required to reach the preceding vehicle when the target inter-vehicle distance is moved at the current vehicle speed. The inter-vehicle time is the time required to reach the preceding vehicle when moving the current distance at the current vehicle speed.
S40: The inter-vehicle control ECU 13 calculates the inter-vehicle time deviation by subtracting the inter-vehicle time from the target inter-vehicle time. When the inter-vehicle time deviation is positive, the inter-vehicle distance is short with respect to the target inter-vehicle distance, and when negative, the inter-vehicle distance is long with respect to the target inter-vehicle distance.
S50: The inter-vehicle control ECU 13 calculates a target acceleration by calculating a relative speed and an inter-vehicle time deviation. When the relative speed is positive, the preceding vehicle is moving away, so the own vehicle should be accelerated. When the relative speed is negative, the preceding vehicle is approaching, and the own vehicle should be decelerated. If the inter-vehicle time deviation is positive, the current distance is short relative to the target inter-vehicle distance, so the vehicle should be decelerated.If the inter-vehicle time deviation is negative, the current distance is long relative to the target inter-vehicle distance. The vehicle should be accelerated. Therefore, the target acceleration can be obtained by multiplying an appropriate coefficient (gain) by the relative speed and the inter-vehicle time deviation and adding them with the signs reversed.
Target acceleration = -K1 x relative speed + K2 x inter-vehicle time deviation In addition to the relative speed and inter-vehicle time deviation, the target acceleration may be determined from the differential value of the relative speed or the differential value of the inter-vehicle time deviation. The determination method is an example.
S60: The inter-vehicle control ECU 13 calculates the acceleration deviation by subtracting the current acceleration from the target acceleration. The required driving force instructed to the engine ECU 14 and the skid control ECU 15 is determined from the acceleration deviation.

[Control of target acceleration]
FIG. 4 is an example of a functional block diagram of the inter-vehicle control ECU 13 of the present embodiment, and FIG. 5 is an example of a flowchart showing a procedure for suppressing the target acceleration. The speed determination unit 32 determines whether or not the vehicle speed Va of the host vehicle A and the vehicle speed Vb of the preceding vehicle B are in the degree of identification. The inter-vehicle time calculation unit 33 calculates the inter-vehicle time Tbc from the above equation (1). The acceleration suppression determination unit 34 determines whether to suppress the target acceleration by comparing the inter-vehicle time Tbc with a threshold value. The target acceleration calculation unit 31 calculates the target acceleration, for example, according to the procedure of FIG. 3, and suppresses the target acceleration when instructed to suppress the target acceleration. Details will be described later.

  The procedure of FIG. 5 shows processing that is effective when another vehicle C interrupts, and the own vehicle A captures another vehicle C other than the preceding vehicle and the other vehicle C interrupts or interrupts. It is executed when is predicted. The predicted case is, for example, when the lateral position of the other vehicle C is moving to the own vehicle lane at a speed equal to or higher than a predetermined value, when the lateral position of the other vehicle C reaches the own vehicle lane, or other For example, the blinker lamp of the vehicle C flashes.

  The target acceleration calculation unit 31 calculates the target acceleration for the other vehicle C by the method described above as an example or other methods (S1).

  Next, the speed determination unit 32 determines whether or not the vehicle speed Va of the host vehicle A and the vehicle speed Vb of the preceding vehicle B are close (S2). The vehicle speed Va and the vehicle speed Vb of the preceding vehicle are close, for example, it may be determined that the difference is within a few [km / h], for example, that there is no difference that can be identified, in other words, that the vehicle is following the preceding vehicle B. State. If the vehicle has not followed the preceding vehicle B, the vehicle has accelerated following the other vehicle C, but the host vehicle A may not decelerate after the other vehicle C leaves.

  When the vehicle speed Va and the vehicle speed Vb are not close (No in S2), the inter-vehicle control ECU 13 controls the vehicle with the target acceleration calculated in step S1 (S6). Therefore, it is possible to prevent the target acceleration from being excessively suppressed by the determination in S2.

  When the vehicle speed Va and the vehicle speed Vb are close (Yes in S2), the inter-vehicle time calculation unit 33 calculates the inter-vehicle time Tbc until the other vehicle C reaches the preceding vehicle B (S3).

  If the inter-vehicle time Tbc is small, the interrupted other vehicle C may approach the preceding vehicle B in a short time, so it can be estimated that the driver of the other vehicle C may immediately leave. For this reason, the acceleration suppression determination part 34 determines whether the inter-vehicle time Tbc is less than a threshold value (S4). The threshold value is, for example, a fixed value such as several seconds or a variable value corresponding to the vehicle speed of the host vehicle.

  If the inter-vehicle time Tbc is not less than the threshold value (No in S4), the inter-vehicle control ECU 13 controls the vehicle with the target acceleration calculated in step S1 (S6). After it is determined that the other vehicle C has interrupted, there are cases where Vc> Va, Va> Vc, and Vc = Va as the vehicle speed relationship, but if Vc> Va, the vehicle is accelerated, and if Va> Vc. When Vc = Va, the vehicle is decelerated as much as the inter-vehicle distance is shorter than when the preceding vehicle B is captured. In any case, since the target acceleration is not suppressed, the inter-vehicle control ECU promptly maintains the inter-vehicle distance from the other vehicle C appropriately.

  When the inter-vehicle time Tbc is less than the threshold (Yes in S4), the acceleration suppression determination unit 34 causes the target acceleration calculation unit 31 to suppress the target acceleration (S5).

  When the target acceleration calculation unit 31 suppresses the target acceleration and accelerates the other vehicle C, which may break between the host vehicle A and the preceding vehicle B and may immediately leave, to maintain the inter-vehicle distance. The target acceleration can be suppressed. Assuming that the vehicle speed of the preceding vehicle B is constant when the other vehicle C leaves, the necessity of decelerating for the inter-vehicle distance control is reduced, or even if decelerating is necessary, it is necessary for the inter-vehicle distance control. Deceleration can be reduced.

FIG. 6 is an example of a diagram illustrating suppression of target acceleration. The suppression of the target acceleration is expressed by, for example, multiplying the target acceleration by “1 / limitation coefficient”. However, “restriction coefficient> 1”.
Suppressed target acceleration = target acceleration / limitation coefficient FIG. 6A shows a limit coefficient when the target acceleration is suppressed at a constant ratio. The suppression of the target acceleration may be performed until the other vehicle C leaves or the suppression of the target acceleration is unnecessary. The suppression of the target acceleration is not necessary when the other vehicle C approaches the preceding vehicle B and decelerates or when a predetermined time has elapsed after interruption. When the other vehicle C approaches the preceding vehicle B and decelerates, the vehicle speed Vc> Vb is not satisfied, so that it can be regarded as the case where the vehicle does not leave. When the predetermined time has elapsed after the interruption, it is conceivable that the other vehicle C gradually decelerates and the vehicle speed Vc> Vb is not satisfied, or that no detection is made even when the other vehicle C leaves.

  The predetermined time is set as follows. The other vehicle C approaching the preceding vehicle B and decelerating is considered to occur within a time shorter than the inter-vehicle time Tbc. Therefore, the predetermined time is 50% to 90% of the inter-vehicle time Tbc. In FIG. 6, this time is set as the suppression time. Since it may be determined that the vehicle does not leave when the suppression time has elapsed, the vehicle C may follow the other vehicle C at a normal target acceleration.

  Thus, the inter-vehicle control ECU 13 ends the suppression of the target acceleration when the other vehicle C leaves or the suppression of the target acceleration is not necessary. By terminating the suppression of the target acceleration, the inter-vehicle distance from the preceding vehicle B or the other vehicle C can be quickly maintained at the target inter-vehicle distance.

  Further, the degree of suppression can be set to an optimal value experimentally. In the figure, the limiting coefficient is 1.2 to 3 (the target acceleration is suppressed to about 0.33 to 0.83), but this is merely an example. Further, the limiting coefficient may be variable according to the vehicle speed Va of the host vehicle. For example, by increasing the limiting coefficient as the vehicle speed of the host vehicle increases, it is easy to reduce acceleration / deceleration in the high speed range when an interruption or departure occurs.

  Further, the suppression of the target acceleration may include setting the target acceleration to zero (corresponding to the limit coefficient being infinite). In this case, the own vehicle A travels at a constant speed while the inter-vehicle control ECU 13 limits the target acceleration. If the other vehicle C leaves while the target acceleration is zero, the follow-up traveling to the preceding vehicle B can be started with the vehicle speed Vb = Va. Even if the other vehicle C does not leave while the target acceleration is zero, the other vehicle C decelerates. Therefore, when the suppression time has elapsed, the own vehicle A follows the other vehicle C of the vehicle speed Vc = Vb. Therefore, the follow-up traveling to the preceding vehicle B can be started from the state where the vehicle speed Vc = Va. Therefore, by setting the target acceleration to zero, it is possible to reduce the deceleration amount rather than suppressing the target acceleration to a value larger than zero.

  FIG. 6B is an example of a diagram showing a limiting coefficient when it decreases with time. The limiting coefficient decreases with time from a predetermined maximum value or a maximum value determined according to the vehicle speed. Immediately after the other vehicle C interrupts, the amount of restraint is large, and when it leaves, the acceleration until the other vehicle C leaves can be reduced as much as possible. In addition, when the other vehicle C does not leave, the amount of suppression is gradually reduced. Therefore, when the other vehicle C approaches the preceding vehicle B and decelerates, the amount of suppression of the target acceleration is small. It becomes possible to quickly control the inter-vehicle distance to the target inter-vehicle distance.

[Examples of vehicle behavior]
FIG. 7A to FIG. 7E are examples illustrating a control example of the inter-vehicle control ECU 13 with respect to the behavior of the other vehicle C to be interrupted.

  FIG. 7A is a diagram illustrating initial positions of the host vehicle A, the preceding vehicle B, and the other vehicle C. This state is close to the state assumed in step S20 of FIG.

  FIG. 7B is a diagram illustrating a situation where the other vehicle C starts an interruption or a situation where it is determined to interrupt. Already, the distance to the other vehicle C, the relative speed, the lateral position, etc. are acquired, and the inter-vehicle time Tbc is calculated. It is determined whether or not the calculated inter-vehicle time Tbc is less than a threshold value.

  FIG.7 (c) is a figure which shows the condition immediately after the other vehicle C interrupted. If Vc> Vb, the other vehicle C approaches the preceding vehicle B. The host vehicle A determines that the inter-vehicle time Tbc is less than the threshold, and suppresses the target acceleration. The own vehicle A starts the inter-vehicle distance control with the vehicle C as the preceding vehicle while suppressing the target acceleration at the time when the other vehicle C interrupts or is predicted to interrupt.

  FIG. 7D is a diagram illustrating a situation where the other vehicle C does not leave after FIG. 7C. Since Vc> Vb, but does not leave, the other vehicle C approaches the preceding vehicle B too much, and the other vehicle C decelerates. As a result of deceleration, Vc decreases and approaches Vb.

  The own vehicle A detects the deceleration of the other vehicle C, ends the suppression of the target acceleration in the inter-vehicle distance control using the other vehicle C as the preceding vehicle, and controls the target acceleration that is not suppressed (normal).

  FIG. 7 (e) is a diagram illustrating a situation in which the other vehicle C has left after FIG. 7 (c). Since the other vehicle C has left, the own vehicle A finishes the inter-vehicle distance control and the suppression of the target acceleration with the vehicle C as the preceding vehicle, and the inter-vehicle distance at the uncontrolled (normal) target acceleration for the preceding vehicle B. Take control.

  Therefore, in the situation of FIG. 7 (e), the host vehicle A is not approaching the other vehicle C, so that unnecessary deceleration can be suppressed even if the preceding vehicle B is switched to the target of the follow-up travel.

FIG. 8 is an example of a diagram for explaining another vehicle situation in which interruption and separation may occur.
FIG. 8A is an example of a diagram illustrating a vehicle situation in which another vehicle C interrupts and leaves from the left lane. For example, since the approach direction of the other vehicle C is reversed left and right as compared with FIG. 7 described so far, the inter-vehicle control ECU 13 can similarly suppress the target acceleration.

  FIG. 8B is an example of a diagram for explaining a vehicle situation in which interruption and departure may occur on a three-lane road on one side. The host vehicle A and the preceding vehicle B are traveling in the center lane. When the other vehicle C interrupts, there is a possibility of leaving either the left lane or the right lane. Of these, when leaving the right lane, it may be considered the same as FIG. When leaving the left lane, the inter-vehicle control ECU 13 may similarly suppress the target acceleration, but in this case, depending on the other vehicle C, the lane may be continuously changed. The need to follow C is low. For this reason, for example, the vehicle control ECU restricts the target acceleration when the other vehicle C is the preceding vehicle to zero (constant speed travel), and after traveling at a constant speed, the other vehicle C does not leave (the suppression time has elapsed). Follow-up). As a result, it is possible to suppress repeated short-time acceleration and deceleration due to frequent switching of the preceding vehicle B. FIG. 8C shows a vehicle situation in which the left-right relationship is reversed from FIG. 8B, and therefore, control may be performed in the same manner as in FIG. 8B.

  For host vehicle A, it can be determined from the navigation information, the recognition result of the white line, road-to-vehicle communication, and the like that the road being traveled is one lane on one side and traveling in the center lane.

  FIG. 9A is an example of a diagram for explaining another vehicle situation in which interruption and separation may occur. In FIG. 9A, the other vehicle C has entered the front of the own vehicle A on the one-lane two-lane road, but the other vehicle D travels in the right lane of the own vehicle A at the same speed as the vehicle B. ing. In such a vehicle situation, it is considered that the possibility that the other vehicle C will leave is low, and it is considered that the other vehicle C approaches the preceding vehicle B in a short time after the interruption and decelerates. Since the vehicle speed Vc after deceleration is considered to be approximately the same as the vehicle speed Vb of the preceding vehicle B, the host vehicle A can follow the vehicle speed Vc of the other vehicle C as Vb immediately after the other vehicle C interrupts. it can.

  As a result, the vehicle speed Vb of the preceding vehicle B remains the same and the inter-vehicle distance is shortened. Therefore, even if the vehicle speed Vc of the other vehicle C is greater than the vehicle speed Vb of the preceding vehicle B, the inter-vehicle distance is increased without acceleration. However, the vehicle can follow the other vehicle C (by weak deceleration).

  The fact that the other vehicle C does not leave (the presence of the other vehicle D) means that the other vehicle D is detected while the preceding vehicle B is being captured, so that the vehicle speed of the other vehicle D can be estimated. .

  Similarly, in FIG. 9B, on the three-lane road on one side, the other vehicle C has interrupted the front of the own vehicle A, but the other vehicle D has a vehicle speed similar to that of the vehicle B on the left lane of the own vehicle. Running. Also in this case, it is considered that the possibility that the other vehicle C will leave is low, and it is effective to suppress the target acceleration as in FIG.

  As described above, the inter-vehicle distance control device 100 according to the present embodiment calculates the inter-vehicle time Tbc when the other vehicle C having a higher vehicle speed than the preceding vehicle B has interrupted the front of the host vehicle A, and the other vehicle C Since it can be determined whether or not the vehicle will leave or decelerate in the near future, it is possible to determine whether the acceleration control is changed or the acceleration is necessary.

12 sensor unit 13 inter-vehicle control ECU
14 Engine ECU
15 Skid control ECU
17 Throttle motor 19 Wheel speed sensor 20 Brake ACT
DESCRIPTION OF SYMBOLS 21 Radar sensor 22 Camera sensor 31 Target acceleration calculating part 32 Speed determination part 33 Inter-vehicle time calculation part 34 Acceleration suppression determination part

Claims (5)

An inter-vehicle distance control device that detects a preceding vehicle ahead of the host vehicle and controls a distance between the preceding vehicle and the host vehicle,
Vehicle speed distance detecting means for detecting a relative speed with the preceding vehicle and a distance with the own vehicle;
Acceleration / deceleration determining means for determining acceleration or deceleration for controlling the inter-vehicle distance with the preceding vehicle to the target inter-vehicle distance based on the relative speed and the distance detected by the vehicle speed distance detecting means;
When another preceding vehicle interrupts between the preceding vehicle and the host vehicle in a state of following the preceding vehicle at the acceleration or the deceleration determined by the acceleration / deceleration determining means, An inter-vehicle time calculating means for calculating an inter-vehicle time with the other preceding vehicle;
The acceleration / deceleration determining means for controlling the inter-vehicle distance from the interrupted other preceding vehicle to the target inter-vehicle distance when it is determined that the other preceding vehicle is further away from the host vehicle because the inter-vehicle time is smaller than the threshold value. It has but the acceleration to determine, and a suppressing acceleration and deceleration control means than the acceleration which is determined based on the relative velocity and the distance the vehicle distance detecting means has detected relative to the another preceding vehicle interrupted ,
The acceleration / deceleration control means suppresses the acceleration most immediately immediately after the other preceding vehicle interrupts, reduces the amount of acceleration suppression with time immediately after the interruption, and accelerates after a certain time shorter than the inter-vehicle time. The inter-vehicle distance control device is characterized in that the control for suppressing the vehicle is terminated . The acceleration / deceleration control means keeps the acceleration / deceleration constant for controlling the inter-vehicle distance from the other preceding vehicle to the target inter-vehicle distance when it is determined that the other preceding vehicle moves away from the host vehicle according to the inter-vehicle time. Suppress to time zero,
The inter-vehicle distance control device according to claim 1. Only when the vehicle speed of the host vehicle is similar to the vehicle speed of the preceding vehicle,
When it is determined that the other preceding vehicle is further away from the host vehicle due to the inter-vehicle time, the acceleration / deceleration control means sets the acceleration for controlling the inter-vehicle distance with the other preceding vehicle to the target inter-vehicle distance, Suppress the acceleration determined from the relative speed and distance with the preceding vehicle,
The inter-vehicle distance control device according to claim 1 or 2.   The inter-vehicle distance control device according to any one of claims 1 to 3, wherein the acceleration / deceleration control means ends the control for suppressing the acceleration when the other preceding vehicle leaves. When the parallel traveling vehicle of the preceding vehicle is traveling in the lane that was traveling before the other preceding vehicle interrupted,
The acceleration / deceleration determining means determines whether the other preceding vehicle is based on the relative speed with the other preceding vehicle and the distance with the other preceding vehicle, which are considered to be equal to the relative speed with the preceding vehicle. Determining an acceleration for controlling the inter-vehicle distance to the target inter-vehicle distance, and following the other preceding vehicle with the determined acceleration itself ,
The inter-vehicle distance control device according to any one of claims 1 to 4, wherein

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