JP2007153080A - Following travel controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an operation support device for a vehicle capable of simplifying control and capable of reducing unfamiliar feeling caused by switching travel control between constant travel control and following travel control. <P>SOLUTION: A travel control unit 5 sets an virtual preceding vehicle (dummy preceding vehicle) constant-speed-traveling at a set vehicle speed by a driver, when detecting no preceding vehicle by a stereo image recognizer 4, computes various kinds of information (dummy preceding vehicle information) concerned in the dummy preceding vehicle, and attains the constant travel control by conducting the following travel control with respect to the dummy preceding vehicle, based on the dummy preceding vehicle information, as a result thereof. The constant travel control and the following travel control are attained thereby by the single travel control (following travel control), so as to simplify the control, and so as to reduce the unfamiliar feeling caused by switching the travel control between the constant travel control and the following travel control. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a driving support device for a vehicle that performs follow-up traveling control for controlling the distance between the preceding vehicle when a preceding vehicle is present, and performs constant-speed traveling control at a vehicle speed set by a driver when there is no preceding vehicle. .

2. Description of the Related Art In recent years, a driving assistance device that detects a traveling environment ahead using a vehicle-mounted camera or the like, detects a preceding vehicle from the traveling environment data, and performs follow-up traveling control on the preceding vehicle has been put into practical use. In this type of driving support device, in general, when the preceding vehicle ahead of the own vehicle traveling path is lost, the vehicle shifts to the constant speed traveling control at the vehicle speed set by the driver. In order to reduce the occupant's uncomfortable feeling when switching between the following traveling control and the constant speed traveling control, for example, in Patent Document 1, when the loss of the preceding vehicle is determined during the following traveling control, the state corresponding to the preceding vehicle lost is determined. A technique is disclosed in which a transition parameter is set, a travel control according to the transition parameter is executed, and then a transition is made to a constant speed travel control at a set vehicle speed.
JP 2002-178787 A

  However, in this type of driving support device, the form of travel control differs between the follow-up travel control and the constant speed travel control, so the control becomes complicated. Further, as in the technique disclosed in Patent Document 2 described above, even if the transition from the follow-up travel control to the constant speed travel control is performed gently using the transition parameter or the like, different forms of travel control are switched. It may be difficult to sufficiently reduce the uncomfortable feeling caused by.

  The present invention has been made in view of the above circumstances, and while simplifying the control, it is possible to reduce the uncomfortable feeling caused by switching between running control between constant speed running control and follow-up running control. The purpose is to provide.

  The present invention relates to own vehicle running information detecting means for detecting running information of the own vehicle, preceding vehicle information detecting means for recognizing a preceding vehicle and detecting the preceding vehicle information, and preceding vehicle information using the preceding vehicle information detecting means. When detecting, the following traveling control means for controlling the inter-vehicle distance from the preceding vehicle based on the preceding vehicle information, and when the preceding vehicle information is not detected by the preceding vehicle information detecting means, the vehicle travels at the set vehicle speed. Virtual preceding vehicle information calculating means for setting a virtual preceding vehicle and calculating the virtual preceding vehicle information, and when the following traveling control means does not detect the preceding vehicle information by the preceding vehicle detecting means, The inter-vehicle distance from the virtual preceding vehicle is controlled based on the virtual preceding vehicle information.

  According to the vehicle driving support device of the present invention, it is possible to simplify the control and reduce a sense of incongruity due to the switching of the traveling control between the constant speed traveling control and the tracking traveling control.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 13 show an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of a driving support device mounted on a vehicle, FIG. 2 is a flowchart of a follow-up running control program, and FIG. 3 is a control target time t0 calculation routine. 4 is a flowchart of a control target time t0 correction routine, FIG. 5 is a flowchart continuing from FIG. 4, FIG. 6 is a flowchart of a control target time t0 interrupt control correction routine, and FIG. 7 is a flowchart of a preceding vehicle predicted position Lf calculation routine. FIG. 8 is a flowchart of a target acceleration a calculation routine, FIG. 9 is a flowchart of a control routine corresponding to the target acceleration a, FIG. 10 is an explanatory diagram of the inter-vehicle distance with the preceding vehicle and the inter-vehicle distance to be secured before the preceding vehicle, 11 is an explanatory diagram of the predicted position of the preceding vehicle, FIG. 12 is an explanatory diagram of the target inter-vehicle distance when the control target time has elapsed, and FIG. 13 is a constant speed run It is a flow chart of a control program.

  In FIG. 1, reference numeral 1 denotes a vehicle such as an automobile (own vehicle). The vehicle 1 is equipped with a cruise control system (ACC (Adaptive Cruise Control) system) 2 as an example of a vehicle driving support device. . The ACC system 2 mainly includes a stereo camera 3, a stereo image recognition device 4, and a travel control unit 5. In the ACC system 2, basically, when there is a preceding vehicle, the preceding vehicle is present. The follow-up running control holding a predetermined inter-vehicle distance is performed, and when there is no preceding vehicle, the constant speed running control holding the vehicle speed set by the driver is performed. Although details will be described later, in this follow-up running control, an inter-vehicle distance Dstop to be secured in advance is set before the preceding vehicle, and a time until the inter-vehicle distance Dstop to be secured is set as a control target time t0. Then, the predicted position Lf of the preceding vehicle when the control target time t0 has elapsed is calculated, and based on the inter-vehicle distance L with the current preceding vehicle and the predicted position Lf of the preceding vehicle when the control target time t0 has elapsed, the control target time The acceleration from the current host vehicle speed V0, which is the target target vehicle distance Dtgt that is set in advance as the target vehicle distance Dtgt at the host vehicle speed Vtgt when t0 has elapsed, is calculated as the target acceleration a, and automatic brake control (including follow-up stop control is also included) ) And automatic acceleration control (including follow-up start control). Further, in the constant speed traveling control, a virtual preceding vehicle (dummy leading vehicle) that travels in front of the own vehicle traveling path at the vehicle speed (set vehicle speed) set by the driver is set, and based on the traveling state of the own vehicle 1, etc. The dummy preceding vehicle information such as the acceleration of the dummy preceding vehicle and the distance between the own vehicle and the dummy preceding vehicle (preceding vehicle distance) is calculated. And the constant speed traveling control is performed as a result by performing the traveling control similar to the above-mentioned following traveling control with respect to the set dummy preceding vehicle. The following traveling control and the constant speed traveling control are executed by the traveling control unit 5, and therefore the traveling control unit 5 is configured to have functions as a following traveling control means and a dummy preceding vehicle information calculation means. Is.

  The stereo camera 3 is composed of a pair of (left and right) CCD cameras using a solid-state image sensor such as a charge coupled device (CCD) as a stereo optical system. Are attached at regular intervals, and an object outside the vehicle is imaged in stereo from different viewpoints and output to the stereo image recognition device 4.

  In addition, the host vehicle 1 includes a vehicle speed sensor 6 that detects the host vehicle speed V 0, a brake switch 7 that detects ON / OFF of the brake pedal of the host vehicle 1, and front and rear of the host vehicle 1 as host vehicle travel information detection means. A longitudinal acceleration sensor 12 for detecting acceleration is provided. The host vehicle speed V0 is output to the stereo image recognition device 4 and the travel control unit 5. Further, the brake pedal ON-OFF signal from the brake switch 7 and the longitudinal acceleration Gx from the longitudinal acceleration sensor 12 are input to the traveling control unit 5.

  The stereo image recognition device 4 receives the image from the stereo camera 3 and the vehicle speed V0 from the vehicle speed sensor 6 and detects the front information of the three-dimensional object data and the white line data ahead of the vehicle 1 based on the image from the stereo camera 3. Then, the traveling path of the host vehicle 1 (the host vehicle traveling path) is estimated. Then, the preceding vehicle ahead of the host vehicle 1 is extracted, the preceding vehicle distance (inter-vehicle distance) L, the preceding vehicle speed ((change amount of the inter-vehicle distance L) + (own vehicle speed V0)) Vf, the preceding vehicle acceleration (preceding vehicle speed Vf). ), A stationary object position other than the preceding vehicle, white line coordinates, white line recognition distance, own vehicle traveling path coordinates, and other data are output to the traveling control unit 5.

  Here, the processing of the image from the stereo camera 3 in the stereo image recognition device 4 is performed as follows, for example. First, with respect to a pair of stereo images in the traveling direction environment of the host vehicle 1 captured by the CCD camera of the stereo camera 3, a process for obtaining distance information over the entire image from the corresponding positional deviation amount by the principle of triangulation. To generate a distance image representing a three-dimensional distance distribution. And based on this data, compared with the well-known grouping processing and pre-stored three-dimensional road shape data, solid object data, etc., white line data, guardrails, curbs, etc. existing along the road Side wall data and three-dimensional object data such as vehicles are extracted. In the three-dimensional object data, the distance to the three-dimensional object and the temporal change (relative speed with respect to the own vehicle 1) of this distance are obtained. A vehicle traveling at a predetermined speed (for example, 0 km / h or more) is extracted as a preceding vehicle. Of the preceding vehicles, a vehicle having a speed Vf of approximately 0 km / h is recognized as a stopped preceding vehicle. Thus, the stereo camera 3 and the stereo image recognition device 4 are provided as preceding vehicle information detection means.

  The traveling control unit 5 performs constant speed traveling control to maintain the traveling speed set by the driver's operation input and the function of the following traveling control for the preceding vehicle detected by the stereo image recognition device 4. In addition to the switches and sensors described above, the constant speed travel switch 8 composed of a plurality of switches connected to a constant speed travel operation lever provided on the side of the steering column or the like. The stereo image recognition device 4 and the like are connected.

  The constant speed travel switch 8 is a vehicle speed set switch for setting the target vehicle speed during constant speed travel, a coast switch for mainly changing the target vehicle speed to the lower side, a resume switch for changing the target vehicle speed to the upper side, etc. It is configured. Further, a main switch (not shown) for turning ON / OFF constant speed traveling control and follow-up traveling control is disposed in the vicinity of the constant speed traveling operation lever.

  When the driver turns on a main switch (not shown) and sets a desired speed with the constant speed traveling operation lever, a signal from the constant speed traveling switch 8 is input to the traveling control unit 5. Then, a signal is output to the throttle valve control device 9 so that the vehicle speed detected by the vehicle speed sensor 6 converges to the set vehicle speed set by the driver, and the opening degree of the throttle valve 10 is feedback-controlled, so that the vehicle 1 is automatically Or running at a constant speed, or outputting a deceleration signal to the automatic brake control device 11 to activate the automatic brake.

  Further, when the traveling control unit 5 performs constant speed traveling control and recognizes a preceding vehicle by the stereo image recognition device 4, the traveling control unit 5 is automatically switched to follow-up traveling control described later under a predetermined condition. . The constant speed travel control function and the follow-up travel control function are used when the driver steps on the brake, when the host vehicle speed V0 exceeds a preset upper limit value, or the main switch is turned off. If it is, it is canceled.

  That is, as shown in FIG. 2, the follow-up travel control program in the travel control unit 5 first reads necessary parameters in step (hereinafter abbreviated as “S”) 101, proceeds to S102, and travels along the own vehicle. It is determined whether there is a preceding vehicle in front of the vehicle.

  If it is determined in S102 that there is no preceding vehicle, the process proceeds to S103, and after the end of the follow-up running control is determined, the routine is exited. Here, if the end of the follow-up running control is determined in S103, the control unit 5 executes a constant speed running control, which will be described later, instead of the follow-up running control.

  On the other hand, if it is determined in S102 that a preceding vehicle is present, the process proceeds to the process after S104, that is, the process of follow-up running control. When the process proceeds to S104, first, the control target time t0 is calculated. The calculation of the control target time t0 is set according to the control target time t0 calculation routine shown in FIG. The relationship of setting the control target time t0 is shown in FIG.

First, in S201, it is determined whether or not the acceleration a0 of the host vehicle 1 (the differential value of the host vehicle speed V0 or the sensor value from an acceleration sensor (not shown)) is 0 km / h ² , and the acceleration a0 is 0 km / h. ^In the case of ² , the process proceeds to S202, and the control target time t0 is set as the time required to reach the inter-vehicle distance Dstop (arrival position P1 = L-Dstop in FIG. 10) to be secured in advance before the preceding vehicle. Set by equation (1) and exit the routine.
t0 = (L-Dstop) / V0 (1)

As a result of the determination in S201, if the acceleration a0 is not 0 km / h ² , the process proceeds to S203, whether or not the host vehicle 1 can reach the arrival position P1 with the current vehicle speed V0 and acceleration a0, 2) Judgment is made based on whether or not the equation holds.
V0 ² + 2 · a0 · (L−Dstop) ≧ 0 (2)

When this equation (2) is established and it is determined that the host vehicle 1 can reach the arrival position P1 with the current vehicle speed V0 and acceleration a0, the process proceeds to S204, and the control target time t0 is set to the host vehicle 1. Is set by the following equation (3) as the time until the vehicle arrives at the arrival position P1 in the current vehicle speed V0 and acceleration a0, and the routine is exited.
t0 = (− V0 + (V0 ² + 2 · a0 · (L−Dstop)) ^1/2 ) / a0 (3)

If it is determined in S203 that the host vehicle 1 cannot reach the arrival position P1 with the current vehicle speed V0 and acceleration a0, the process proceeds to S205, and the host vehicle speed V0 is determined to be the arrival position P1. Assuming that it becomes 0 (stops), the control target time t0 is set as the time to the arrival position P1 by the following equation (4), and the routine is exited.
^{t0 = V0 2/2 · (} L-Dstop) ... (4)

  Thus, after calculating the control target time t0 in S104 in FIG. 2 (control target time t0 calculation routine shown in FIG. 3), the process proceeds to S105, and the control target time t0 is corrected. The correction of the control target time t0 is performed according to the control target time t0 correction routine shown in FIGS.

  First, in S301, it is determined whether or not the control target time t0 is greater than the inter-vehicle time T and the current inter-vehicle distance L is greater than the target inter-vehicle distance Dtgt. Here, the inter-vehicle time T is a value obtained by dividing the inter-vehicle distance L by the host vehicle speed V0, and is a preset value (for example, 1.6 sec).

The target inter-vehicle distance Dtgt is a value calculated by the following equation (5) using the host vehicle speed V0.
Dtgt = T · V0 + Dstop (5)

When the condition of S301, that is, when t0> T and L> Dtgt holds, the target acceleration a may become smaller as the inter-vehicle distance L becomes larger than the target inter-vehicle distance Dtgt. From the equation (6), the control target time t0 is corrected by the inter-vehicle time T, the inter-vehicle distance L, and the target inter-vehicle distance Dtgt so that the target acceleration a increases as the inter-vehicle distance L increases, and the process proceeds to S303. The equation (6) is an equation determined by experiments or the like.
t0 = (t0 · Dtgt + T · (L−Dtgt)) / L (6)

  On the other hand, if t0> T and L> Dtgt do not hold as a result of the determination in S301, the process proceeds to S303. In S303, the absolute value of the relative speed with respect to the preceding vehicle is smaller than a preset threshold value VT (positive value), that is, VT> (V0−Vf) ≧ −VT is established, and the relative speed with respect to the preceding vehicle is established. It is determined whether or not the absolute value of the speed is small.

  As a result of the determination in S303, if VT> (V0−Vf) ≧ −VT is established and it is determined that the absolute value of the relative speed with the preceding vehicle is small, unnecessary acceleration / deceleration occurs, causing the driver to be In order to prevent giving a natural feeling, the process proceeds to S304, the speed control target time correction value Cv is set to 2, and the process proceeds to S308. The speed control target time correction value Cv is a value that is multiplied by the control target time t0. The larger the speed control target time correction value Cv is, the larger the control target time t0 is. The correction calculation using the speed control target time correction value Cv will be described later.

  On the other hand, if VT> (V0−Vf) ≧ −VT is not satisfied as a result of the determination in S303, the process proceeds to S305 to determine whether −VT> (V0−Vf) ≧ −2 · VT is satisfied. .

  As a result of the determination in S305, if -VT> (V0-Vf) ≧ -2 · VT is not established, the process proceeds to S306, the speed control target time correction value Cv is set to 0 (not corrected), and the process proceeds to S308. Proceed with

If -VT> (V0-Vf) ≥-2 · VT is established as a result of the determination in S305, the process proceeds to S307, and the speed control target time correction value is set between -VT and -2 · VT. The speed control target time correction value Cv is set by the following equation (7) so that Cv can be linearly continuous between 0 and 2, and the process proceeds to S308.
Cv = 2 · (V0−Vf + 2 · VT) / VT (7)

  When the speed control target time correction value Cv is set by any of S304, S306, and S307 and the process proceeds to S308, the absolute value of the difference between the current inter-vehicle distance D and the target inter-vehicle distance Dtgt is preset. The absolute value of the difference between the current inter-vehicle distance D and the target inter-vehicle distance Dtgt is smaller than the predetermined threshold DT (positive value), that is, −DT <(L−Dtgt) <DT. Judge whether it is small.

  As a result of the determination in S308, when -DT <(L-Dtgt) <DT is established and it is determined that the absolute value of the difference between the current inter-vehicle distance D and the target inter-vehicle distance Dtgt is small, In order to prevent unnecessary acceleration / deceleration from occurring and giving the driver an unnatural feeling, the process proceeds to S309, the distance target time correction value CD is set to 2, and the process proceeds to S315. The distance target time correction value CD is a value that is multiplied by the control target time t0, and the larger the control target time t0 is, the larger the target control time t0 is. The correction calculation using the distance target time correction value CD will be described later.

  If -DT <(L-Dtgt) <DT is not satisfied as a result of the determination in S308, the process proceeds to S310, and it is determined whether -2 · DT <(L-Dtgt) ≤-DT is satisfied.

As a result of the determination in S310, when −2 · DT <(L−Dtgt) ≦ −DT is established, the process proceeds to S311 and the distance target time correction value CD is 0 between −2 · DT and −DT. The distance target time correction value CD is set according to the following equation (8) so that it can continue linearly between 1 and 2, and the process proceeds to S315.
CD = 2 · (L−Dtgt + 2 · DT) / DT (8)

  If -2 · DT <(L−Dtgt) ≦ −DT is not satisfied as a result of the determination in S310, the process proceeds to S312 and whether or not DT ≦ (L−Dtgt) <(DT + V0 · β) is satisfied. judge. In this case, β is a constant value, and the determination can be varied depending on the magnitude of the host vehicle speed V0, so that more precise control determination can be performed. As described above, the determinations in S303, S305, S308, S310, and S312 are examples of the respective determinations, and may be varied in consideration of parameters such as the vehicle speed V0 depending on circumstances.

  If DT ≦ (L−Dtgt) <(DT + V0 · β) is not established as a result of the determination in S312, the process proceeds to S313, where the distance target time correction value CD is set to 0 (not corrected), and S315 Proceed to

On the other hand, if DT ≦ (L−Dtgt) <(DT + V0 · β) is satisfied as a result of the determination in S312, the process proceeds to S314, and the distance target time correction value CD is set between DT and (DT + V0 · β). The distance target time correction value CD is set by the following equation (9) so that can continue linearly between 0 and 2, and the process proceeds to S315.
CD = -2. (L-Dtgt-DT-V0.beta.) / (V0.beta) (9)

  When the distance target time correction value CD is set by any of S309, S311, S313, and S314 and the process proceeds to S315, the speed control target time correction value Cv and the distance target time correction value CD are compared, and Cv <CD If so, the process proceeds to S316, and the speed control target time correction value Cv is set to the target time correction value C. If Cv ≧ CD, the process proceeds to S317 and the distance target time correction value CD is set to the target time correction value C. The process proceeds to S318. That is, in S315, the smaller correction value is set to the target time correction value C, and the correction with respect to the control target time t0 is minimized, and the calculated control target time t0 is used as much as possible. is there.

  In S318, the predicted contact time TTC is calculated by the following equation (10) or (11), for example.

When the host vehicle acceleration a0 is set to 0 and the preceding vehicle acceleration af is taken into consideration, the predicted contact time TTC until contacting the preceding vehicle is
TTC = ((V0−Vf) − ((V0−Vf) ² −2 · af · L) ^1/2 ) / af
(10)
Also, if the preceding vehicle is stopped at the time of contact,
TTC = (L + (Vf ² / (2 · af))) / V 0 (11)

Thereafter, the process proceeds to S319, where it is determined whether there is a margin in the predicted contact time TTC, for example, whether it is longer than 10 seconds. If it is longer than 10 seconds, the process proceeds to S320, and S316 is calculated by the following equation (12). Alternatively, the control target time t0 is corrected using the target time correction value C set in S317, and the process proceeds to S324.
t0 = t0 · (1 + C) (12)

  As a result of the determination in S319, if it is determined that TTC ≦ 10 sec and it cannot be said that there is a margin, the process proceeds to S321, and it is determined whether or not the predicted contact time TTC has no margin. In this embodiment, for example, it is determined that there is no margin for 7 seconds or less, and if it is determined that TTC ≦ 7 sec and there is no margin as a result of the determination in S321, the process proceeds to S322, and the target time correction value Correction by C is not performed, that is, t0 = t0, and the process proceeds to S324.

If it is determined in S321 that TTC> 7 sec and there is no room, the process proceeds to S323, and the target time correction value C set in S316 or S317 is used by the following equation (13), for example. The control target time t0 is corrected to proceed to S324.
t0 = t0 · (1 + C · (TTC−7) / 3) (13)

  That is, the processes from S318 to S323 described above are processes in which safety is given priority over comfort when the predicted contact time TTC is small, and the target time correction value C is varied according to the predicted contact time TTC. As a result, the optimum balance between comfort and safety can be achieved.

When the control target time t0 is corrected by any of S320, S322, and S323 and the process proceeds to S324, the control target time t0 is compared with the predicted contact time TTC. If t0 ≦ TTC, the process proceeds to S325. Then, the control target time t0 is set as it is and the routine is exited. Conversely, if t0> TTC, the process proceeds to S326, the control target time t0 is limited to the predicted contact time TTC, and the routine is exited. That is, this restriction ensures that the possibility of contact is eliminated.
Thus, after correcting the control target time t0 in S105 in FIG. 2 (control target time t0 correction routine shown in FIGS. 4 to 5), the process proceeds to S106, and interrupt control correction of the control target time t0 is performed. The interrupt control correction of the control target time t0 is performed according to the control target time t0 interrupt control correction routine shown in FIG.

  First, in S401, the predicted contact time TTC is calculated by the above-described equation (10) or (11).

  Thereafter, the process proceeds to S402, where it is determined whether or not the inter-vehicle distance L is equal to or greater than the target inter-vehicle distance Dtgt. If the inter-vehicle distance L is smaller than the target inter-vehicle distance Dtgt, the process proceeds to S403 and the preceding vehicle acceleration af is −0.1 · G. It is determined whether the vehicle speed V0 is the following deceleration and the host vehicle speed V0 is greater than the preceding vehicle speed Vf. If this condition is satisfied, it is determined that the vehicle is in an interrupted state, and the process proceeds to S404.

  Conversely, if the inter-vehicle distance L is greater than or equal to the target inter-vehicle distance Dtgt in S402, or if the condition in S403 is not satisfied, it is determined that there is no interruption state, the process proceeds to S407, and the control target time t0 is directly set to t0. Set to to exit the routine.

If it is determined in S402 that L <Dtgt and the condition of S403 is satisfied and the process proceeds to S404, it is determined whether or not there is a margin in the predicted contact time TTC, for example, whether it is longer than 10 seconds. In S405, the control target time t0 is corrected by using the interrupt control correction value Cin (a constant set in advance by experiment or the like: 5) according to the following equation (14), and the routine is exited.
t0 = t0 · (1 + Cin) (14)

  As a result of the determination in S404, if it is determined that TTC ≦ 10 sec and it cannot be said that there is a margin, the process proceeds to S406, and it is determined whether or not the predicted contact time TTC has no margin. In this embodiment, for example, when it is determined that there is no margin for 2 seconds or less, and TTC ≦ 2 sec is determined as a result of the determination in S406, the process proceeds to S407, and the control target time t0 Is not performed, that is, the routine exits with t0 = t0.

If it is determined in S406 that TTC> 2 sec and there is no room, the process proceeds to S408, and the control target time t0 is set by using the interrupt control correction value Cin by the following equation (15), for example. Correct and exit the routine.
t0 = t0 · (1 + Cin · (TTC-2) / 8) (15)

  That is, the control target time t0 interrupt control correction is a correction that largely corrects the control target time t0 in accordance with the predicted contact time TTC so that unnecessary rapid deceleration of braking does not occur at the time of interrupt.

  Thus, after correcting the control target time t0 in S106 in FIG. 2 (control target time t0 interrupt control correction routine shown in FIG. 6), the process proceeds to S107, and the preceding vehicle predicted position Lf is calculated. The calculation of the preceding vehicle predicted position Lf is performed according to the preceding vehicle predicted position Lf calculation routine shown in FIG. 7, and the calculation relationship of the preceding vehicle predicted position Lf is shown in FIG.

  First, in S501, it is determined whether or not the preceding vehicle is stopped, that is, whether or not Vf = 0. If Vf = 0, the process proceeds to S502 to set Lf = 0 and exit from the routine.

  If Vf ≠ 0 as a result of the determination in S502, the process proceeds to S503, whether or not the preceding vehicle is stopped at the control target time t0, that is, af ≠ 0 and t0 ≦ −Vf / af. It is determined whether or not is established.

As a result of the determination in S502, if the preceding vehicle is stopped at the control target time t0, the process proceeds to S504, the preceding vehicle predicted position Lf is set by the following equation (16), and the routine is exited.
Lf = −Vf ² / (2 · af) (16)

As a result of the determination in S503, if the preceding vehicle has not stopped at the control target time t0, the process proceeds to S505, the preceding vehicle predicted position Lf is set by the following equation (17), and the routine is exited.
Lf = Vf · t0 + (1/2) · af · t0 ² (17)

Thus, after calculating the preceding vehicle predicted position Lf in S107 in FIG. 2 (preceding vehicle predicted position Lf calculation routine shown in FIG. 7), the process proceeds to S108 and the target acceleration a is calculated. The calculation of the target acceleration a is performed according to a target acceleration a calculation routine shown in FIG.
That is, in S601, the target acceleration a is calculated by the following equation (18), and the routine is exited.
a = (L + Lf−Dstop− (T + t0) · V0) / (t0 · T + (1/2) · t0 ² )
... (18)
This equation (18) is derived from the host vehicle speed Vtgt when t0 has elapsed and the target inter-vehicle distance Dtgt0 when t0 has elapsed, and the relationship between the optimum movement distance when t0 has elapsed is as follows: As is clear from FIG.
L + Lf− (T · Vtgt + Dstop) = t0 · T + (1/2) · a · t0 ² (19)
Therefore, this is an equation obtained by transforming this with respect to the target acceleration a.

Here, the host vehicle speed Vtgt when t0 has elapsed is calculated by the following equation (20) using the target acceleration a.
Vtgt = V0 + a · t0 (20)

The target inter-vehicle distance Dtgt0 when t0 has elapsed is a value calculated by the following equation (21) using the host vehicle speed Vtgt when t0 has elapsed.
Dtgt0 = T · Vtgt + Dstop (21)

  Thus, after calculating the target acceleration a in S108 in FIG. 2 (the target acceleration a calculation routine shown in FIG. 8), the process proceeds to S109 to perform control according to the target acceleration a and exit the program. The control corresponding to the target acceleration a is performed according to a control routine corresponding to the target acceleration a shown in FIG.

  First, in S701, it is determined whether or not the target acceleration a is smaller than 0. If the target acceleration a is 0 or more, the process proceeds to S702, where the target acceleration a is smaller than aoff (a positive value set in advance) with a small acceleration. It is determined whether or not there is a throttle opening θth = 0.

  As a result of the determination in S702, when the target acceleration a is smaller than aoff and the throttle opening θth = 0, the throttle valve 10 is unnecessarily opened to prevent an unpleasant vibration from being given to the driver. Therefore, the throttle instruction value for the throttle valve control device 9 is set to 0, and the process proceeds to the next brake instruction value calculation in S710.

  If it is determined in step S702 that the target acceleration a is greater than or equal to aoff or the throttle opening is not already 0, the process proceeds to step S704, and the throttle instruction value corresponding to the target acceleration a is set to, for example, a map or the like. To search for and set, and proceed to the next brake instruction value calculation of S710.

  On the other hand, if it is determined in S701 that the target acceleration a is smaller than 0, the process proceeds to S705, and the acceleration value aoff that would be obtained when the throttle opening θth is 0 is added to the target acceleration a. It is determined whether the acceleration value (a + aoff) is less than zero.

  As a result of the determination in S705, if (a + aoff) is 0 or more and the initial target acceleration a is a slight deceleration, the process proceeds to S706, the target acceleration a is set to 0, and the process proceeds to S708.

  On the other hand, if (a + aoff) is smaller than 0, the target acceleration a is set to (a + aoff) and set to a value that takes into account the acceleration value aoff that would be obtained when the throttle opening is 0. move on.

  When the process proceeds from S706 or S707 to S708, it is determined whether −aoff ≦ a <0 and the throttle opening θth ≠ 0 is established. If the throttle opening = 0 already, or a < When the deceleration is -aoff, the process proceeds to S703, where the throttle instruction value for the throttle valve control device 9 is set to 0, and the process proceeds to the next brake instruction value calculation in S710.

  Further, as a result of the determination in S708, if −aoff ≦ a <0 and the throttle opening θth ≠ 0 are established, the throttle instruction value corresponding to the target acceleration a is directly retrieved by, for example, a map or the like. Then, the process proceeds to the next brake instruction value calculation of S710.

  When the process proceeds from any of S703, S704, and S709 to S710, when the target acceleration a requires a deceleration larger than a predetermined value, the brake fluid pressure corresponding to the value is given to the automatic brake control device 11. The signal is set by searching a map or the like as a brake instruction value, and the routine is exited. In S710, when the throttle instruction value is not zero, the brake instruction value is zero.

  In this case, when the target acceleration is around 0, the throttle valve 10 is prevented from being continuously controlled in a short time from fully closed → constant opening → fully closed, etc. Smooth control is possible without giving a natural feeling.

  According to such follow-up running control, the control target time t0 is set in consideration of the current positional relationship between the preceding vehicle and the host vehicle, and the follow-up control is enabled based on the control target time t0. The vehicle can smoothly follow the vehicle ahead of the preceding vehicle without being too close to the vehicle.

  Further, the control target time t0 is set based on the time until the inter-vehicle distance Dstop to be secured in advance before reaching the preceding vehicle and reaching the inter-vehicle distance Dstop to be secured. Thus, the distance between the vehicles is surely secured, and control with improved safety is possible.

  Furthermore, the control target time t0 is corrected in consideration of the balance between riding comfort and safety, and is corrected so that acceleration / deceleration is appropriate even when an interruption occurs. It is possible to realize a high system.

As for the target time correction value C for correcting the control target time t0, the target time correction value C may be greatly changed (corrected) according to the set vehicle interval, specifically, as the set vehicle interval becomes short. For example, from equation (22)
C = Cmin + (Tmax−X) (22)
X is the target inter-vehicle time, Cmin is a constant obtained through experiments, and Tmax is the target inter-vehicle time when the set inter-vehicle distance Dtgt is maximized at the own vehicle speed V0 (inter-vehicle distance that can be set in the follow-up control). It is. As a result, the control target time t0 can be set to a large value, so that the change in the target acceleration can be relaxed, and unnecessary acceleration / deceleration can be prevented from giving an unnatural feeling to the driver.

  Furthermore, when performing the follow-up control, the operation of the throttle valve 10 and the operation of the brake are prevented from being alternately performed frequently, and the system is excellent in ride comfort.

  Next, the constant speed traveling control program in the traveling control unit 5 will be described with reference to the flowchart shown in FIG. This constant speed traveling control program is repeatedly executed at predetermined time intervals. First, in S801, necessary parameters are read, and the process proceeds to S802, in which whether or not a preceding vehicle exists ahead of the own vehicle traveling path. Judgment is made.

  If it is determined in step S802 that a preceding vehicle is present, the process proceeds to step S803, where the end of the constant speed traveling control is determined, and then the routine is exited. Here, when it is determined in S803 that the constant speed traveling control is finished, the traveling control unit 5 executes the above-described following traveling control instead of the constant speed traveling control.

  On the other hand, if it is determined in S802 that there is no preceding vehicle, the dummy preceding vehicle information is calculated by the processing from S804 to S816. That is, first, in S804, the traveling control unit 5 sets a dummy preceding vehicle as a virtual preceding vehicle ahead of the own vehicle traveling path, and the driver travels at a constant speed as the vehicle speed (preceding vehicle speed) Vf of this dummy preceding vehicle. The vehicle speed set through the switch 8 (set vehicle speed) is set. That is, a virtual preceding vehicle (dummy preceding vehicle) that travels at a constant speed at the set vehicle speed in front of the own vehicle traveling path is set.

In subsequent S805, the preceding vehicle distance (the distance between the own vehicle 1 and the dummy preceding vehicle) is calculated as information on the dummy preceding vehicle, and the own vehicle speed V0 is used as a parameter by the equation (23).
L = T ・ V0 + Dstop (23)

  In S806, it is determined whether or not a preceding vehicle has been detected last time (that is, whether or not the current process is a process immediately after switching from follow-up traveling control to constant speed traveling control). If it is determined that a vehicle has been detected, the process proceeds to S807, where a departure flag F indicating that the elapsed time from the departure of the preceding vehicle is currently within the set time tlost is set to “1”.

  In step S808, the preceding vehicle acceleration af as the dummy preceding vehicle information is set to the preceding vehicle acceleration immediately before leaving (the acceleration of the preceding vehicle that has existed until the previous time), and the process proceeds to step S814. Here, in the present embodiment, the set time tlost is set to, for example, the control target time t0 when the preceding vehicle leaves. The set time tlost may be set to a preset fixed time.

  On the other hand, if it is determined in S806 that there is no preceding preceding vehicle and the process proceeds to S809, it is determined whether or not the departure flag F = 1. If F = 1, the process proceeds to S810, and F = 0. The process proceeds to S813.

When the process proceeds from S809 to S810, it is determined whether or not the elapsed time since the preceding vehicle has left is equal to or longer than the set time tlost. If it is determined that the time equal to or longer than the set time tlost has not elapsed, Proceeding to S811, the preceding vehicle acceleration af as the dummy preceding vehicle information is calculated by the equation (24), and then proceeding to S814.
af = af (n−1) −Δa (24)
Here, af (n−1) is the preceding preceding vehicle acceleration, and Δa is a value obtained by dividing the preceding vehicle acceleration af set in S808 by the number of times this program is executed within the set time tlost.

  If it is determined in S810 that the time equal to or longer than the set time tlost has elapsed, the separation flag F is reset (F = 0) in S812, and then the process proceeds to S813.

  When the process proceeds from S809 or S812 to S813, the preceding vehicle acceleration af is set to “0”, and then the process proceeds to S814.

Then, when the process proceeds from S808, S811, or S813 to S814, the currently set preceding vehicle acceleration af is corrected by the equation (25) using the own vehicle speed V0.
af = af + α · (V0−Vf) (25)
Here, in the equation (25), α is a preset constant.

Subsequently, in S815, the currently set preceding vehicle acceleration af is corrected by the equation (26) using the road gradient SL.
af = af + f1 (SL) (26)
Here, in the equation (26), f1 (SL) is a function using the road gradient SL as a parameter, and the value of f1 (SL) increases as the road gradient SL increases. The road gradient SL is calculated by the travel control unit 5 based on the host vehicle speed V0 input from the vehicle speed sensor 6 and the longitudinal acceleration Gx of the host vehicle 1 input from the longitudinal acceleration sensor 12, for example. . That is, the travel control unit 5 calculates, for example, the rate of change (m / s ² ) for each set time of the vehicle speed V 0, and uses the rate of change in vehicle speed (m / s ² ) and the longitudinal acceleration Gx (27 ) To calculate the road gradient SL (%).
Road gradient SL = (longitudinal acceleration Gx−vehicle speed change rate / g) · 100 (27)
Here, in the equation (27), g is a gravitational acceleration.

In subsequent S816, the currently set preceding vehicle acceleration af is corrected by the equation (28) using the own vehicle acceleration a0.
af = af + f2 (a (n-1) -a0) (28)
Here, in the equation (28), a (n−1) is the previous target acceleration. Further, f2 (a (n-1) -a0) is a function having as a parameter the difference between the previously calculated target acceleration a (n-1) and the host vehicle acceleration a0, and f2 (a (n-1) ) -A0) increases as the difference between the target acceleration a (n-1) and the host vehicle acceleration a0 increases.

  Proceeding from S816 to S817, the final dummy preceding vehicle information (preceding vehicle speed Vf, preceding vehicle distance L, preceding vehicle acceleration af) calculated in the above-described processing from S804 to S816 is used as preceding vehicle information. The target acceleration a of the subject vehicle 1 is calculated by executing the same processing as S104 to S108 shown in FIG.

  In subsequent S818, it is checked whether or not the target acceleration a of the host vehicle 1 is greater than or equal to a preset upper limit value amax (for example, amax = 0.2 · g). If the target acceleration a is less than or equal to the upper limit value amax. When it determines, it progresses to S820 as it is.

  On the other hand, if it is determined in S818 that the target acceleration a is larger than the upper limit value amax, the process proceeds to S819, the target acceleration a of the host vehicle 1 is updated to the upper limit value amax, and then the process proceeds to S820.

  Then, when the process proceeds from S818 or S819 to S820, the same acceleration as S109 shown in FIG. 2 is executed using the target acceleration a of the host vehicle 1, and the routine is exited.

  According to such an embodiment, when the preceding vehicle is not detected by the stereo image recognition device 4, the virtual preceding vehicle (dummy leading vehicle) that travels at a constant speed at the vehicle speed set by the driver is set and the dummy preceding vehicle is set. By calculating information related to the vehicle (dummy preceding vehicle information) and performing follow-up traveling control for the dummy preceding vehicle based on the calculated dummy preceding vehicle information, the control is simplified and the traveling control follows the constant speed traveling control. It is possible to reduce a sense of incongruity caused by switching between traveling control. That is, when the preceding vehicle is not detected by the stereo image recognition device 4, the constant speed traveling control is realized as a result of the following traveling control for the dummy preceding vehicle that travels at a constant speed at the set vehicle speed in front of the own vehicle traveling path. As a result, it is possible to realize a travel control that is simple and has no sense of incongruity.

  In this case, when calculating the dummy preceding vehicle information, the acceleration of the dummy preceding vehicle (preceding vehicle acceleration) af is increased as the difference between the own vehicle speed and the set vehicle speed increases, so that the own vehicle speed V0 is set earlier. It can be asymptotic to Vf.

  Further, when calculating the dummy preceding vehicle information, the acceleration of the dummy preceding vehicle (preceding vehicle acceleration) af is increased as the road gradient during traveling of the host vehicle 1 increases, thereby depending on the road gradient during the constant speed traveling control. The influence can be suppressed.

  In addition, when calculating the dummy preceding vehicle information, the dummy preceding vehicle acceleration (preceding vehicle acceleration) af increases as the difference between the previously calculated target acceleration a (n-1) and the current vehicle acceleration a0 increases. By doing so, it is possible to suppress the influence of disturbance and realize good constant speed traveling control.

  Further, the preceding vehicle acceleration af of the dummy preceding vehicle set immediately after the preceding vehicle cannot be detected by the stereo image recognizing device 4 is detected, and the preceding vehicle acceleration af detected by the stereo image recognizing device 4 immediately before the detecting becomes impossible. By calculating based on (n-1), it is possible to effectively reduce the uncomfortable feeling when switching from the follow-up running control to the constant speed running control.

  In this embodiment, the preceding vehicle is recognized on the basis of the image from the stereo camera. However, other technologies, for example, recognition based on information from the millimeter wave radar and the monocular camera are performed. It may be.

Schematic configuration diagram of a driving support device mounted on a vehicle Flow chart of follow-up running control program Flow chart of control target time t0 calculation routine Flow chart of control target time t0 correction routine Flow chart continuing from FIG. Flow chart of control target time t0 interrupt control correction routine Flowchart of the preceding vehicle predicted position Lf calculation routine Flow chart of target acceleration a calculation routine Flow chart of control routine according to target acceleration a Explanatory drawing of the inter-vehicle distance with the preceding vehicle and the inter-vehicle distance that should be secured before the preceding vehicle Explanatory drawing of the predicted position of the preceding vehicle Explanatory drawing of target inter-vehicle distance when control target time has elapsed Flow chart of constant speed running control program

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Own vehicle 2 ... ACC system (driving support device)
3 ... Stereo camera (preceding vehicle information detection means)
4 ... Stereo image recognition device (preceding vehicle information detection means)
5 ... Travel control unit (follow-up travel control means, dummy preceding vehicle information calculation means)
6 ... Vehicle speed sensor (own vehicle travel information detection means)
8 ... Constant speed travel switch 9 ... Throttle valve control device 10 ... Throttle valve 11 ... Automatic brake control device 12 ... Longitudinal acceleration sensor

Claims (6)

Own vehicle running information detecting means for detecting running information of the own vehicle;
Preceding vehicle information detecting means for recognizing a preceding vehicle and detecting the preceding vehicle information;
When the preceding vehicle information is detected by the preceding vehicle information detecting means, follow-up traveling control means for controlling the inter-vehicle distance from the preceding vehicle based on the preceding vehicle information;
When the preceding vehicle information is not detected by the preceding vehicle information detecting means, the virtual preceding vehicle information calculating means for setting the virtual preceding vehicle that travels at the set vehicle speed and calculating the virtual preceding vehicle information,
The following traveling control means controls the inter-vehicle distance from the virtual preceding vehicle based on the virtual preceding vehicle information when the preceding vehicle information is not detected by the preceding vehicle detecting means. Follow-up running control device.   2. The vehicle follow-up travel control apparatus according to claim 1, wherein the virtual preceding vehicle information calculation means calculates an acceleration of the virtual preceding vehicle as the virtual preceding vehicle information.   3. The vehicle follow-up travel control device according to claim 2, wherein the virtual preceding vehicle information calculation means increases the acceleration of the virtual preceding vehicle as the difference between the own vehicle speed and the set vehicle speed increases.   The following traveling of the vehicle according to claim 2 or 3, wherein the virtual preceding vehicle information calculation means increases the acceleration of the virtual preceding vehicle as the road gradient while the host vehicle is traveling increases. Control device. The follow-up running control means calculates a target acceleration of the host vehicle and performs follow-up running control based on the target acceleration,
The virtual preceding vehicle information calculating means increases the acceleration of the virtual preceding vehicle as the difference between the target acceleration previously calculated by the following traveling control means and the current acceleration of the host vehicle increases. The vehicle follow-up travel control device according to any one of claims 2 to 4.   The follow-up travel control unit is configured to determine the acceleration of the virtual preceding vehicle set immediately after the preceding vehicle information detection unit becomes unable to detect the preceding vehicle information based on the acceleration of the preceding vehicle immediately before the detection becomes impossible. 6. The vehicle follow-up travel control device according to claim 2, wherein the vehicle follow-up travel control device is operated.

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