JP2003039979A - Inter-vehicle distance control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate anxiety of an occupant on secondary collision or the like by securing an inter-vehicle distance longer than normal at stop in a traffic jam. SOLUTION: Based on the inter-vehicle distance from a succeeding vehicle, when it is determined that there is no succeeding vehicle or there is a succeeding vehicle but it is accelerating and approaching (Step S5), it goes onto Step S6 where it is determined if peripheral road environment should be considered or not. If a road curvature ahead the vehicle or a road gradient is large, an inter-vehicle distance at stop is calculated (Step S7) for making a stop outside a possible dead corner where one's own vehicle is hard to be seen by the succeeding vehicle due to the road curvature or road gradient. The larger of this inter-vehicle distance and a control constant Lc stop 0 of an inter-vehicle distance longer than an inter-vehicle distance Kv2 at normal stop (Step S8) and the larger of a base target inter-vehicle distance Lc0 set according to the own vehicle speed V is set as a target inter-vehicle distance Lc (Step S9).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle distance control device for controlling a running state of an own vehicle to control an inter-vehicle distance between a preceding vehicle and the own vehicle.

[0002]

2. Description of the Related Art Conventionally, when there is no preceding vehicle, the vehicle travels according to the traveling speed set by the occupant, and when there is a preceding vehicle, the inter-vehicle distance between the preceding vehicle and the host vehicle is detected to detect the occupant. There has been proposed an inter-vehicle distance control device that controls traveling according to an inter-vehicle distance or a relative speed to a vehicle at a speed lower than a set speed.

Also, for example, Japanese Patent Laid-Open No. 2000-118261.
Japanese Patent Laid-Open No. 10-205367 or the like proposes an inter-vehicle distance control device in which the inter-vehicle distance control is performed by expanding the control vehicle speed range to a low vehicle speed range including stop. As described above, by expanding the control vehicle speed range to the low vehicle speed range, it is possible to significantly reduce the frequent braking operation and accelerator operation of the driver at the time of traffic jam and the like, and to reduce the driving load of the driver.

[0004]

In the above-described conventional inter-vehicle distance control device, the acceleration / deceleration control is automatically performed by following the preceding vehicle even in the stop speed range such as during traffic jam, and the preceding vehicle is controlled. When is stopped, the own vehicle is also stopped according to the target inter-vehicle distance. At this time, the distance to the preceding vehicle is 0
When [km / h], that is, the control is performed so as to be a certain constant inter-vehicle distance set as the target inter-vehicle distance for stopping the vehicle.

By the way, in the case of traveling in a traffic jam, when traveling in a traffic jam on an expressway, etc., the distance between the preceding vehicle and the preceding vehicle at the time of stop is usually almost constant although there are individual differences among the drivers. Since the vehicle travels, there is no problem in performing the inter-vehicle distance control so that the certain inter-vehicle distance at the time of stopping is maintained even during the tracking control.
However, when the host vehicle is located at the end of the traffic jam, the distance between the host vehicle and the preceding vehicle may be increased slightly, so that the host vehicle may collide with the preceding vehicle due to the impact of the trailing vehicle. In some cases, the possibility of the next collision can be reduced, and in the unlikely event of a rear-end collision with a following vehicle, some drivers set a wider inter-vehicle distance than the normal inter-vehicle distance.

For such a driver, in the above-described conventional inter-vehicle distance control device, the inter-vehicle distance control is performed so that the vehicle has a certain constant inter-vehicle distance when the vehicle is stopped regardless of traffic congestion or the like. Therefore, considering the risk of a rear-end collision from a following vehicle, there is a problem in that the following vehicle becomes anxious and it is not possible to ride in comfort and peace of mind. Further, when the host vehicle is traveling at the end of the traffic jam and traveling following the preceding vehicle, it may stop near the exit of the curve.

At this time, when the own vehicle is difficult to see from the following vehicle, a hazard lamp or the like may be turned on to cause the following vehicle to find the own vehicle as soon as possible. In this way, when the host vehicle stops at the end of the traffic jam during follow-up control and the stop location is behind a curve that is difficult to see from the following vehicle, the driver is There is a problem that I feel anxious and feel anxiety.

Therefore, the present invention has been made by paying attention to the above-mentioned unsolved problems of the related art, and by changing the target inter-vehicle distance depending on whether or not the own vehicle is at the end of the traffic jam, the traffic jam It is an object of the present invention to provide an inter-vehicle distance control device that does not make passengers feel uneasy even when the vehicle is stopped at.

[0009]

To achieve the above object, an inter-vehicle distance control device according to claim 1 of the present invention comprises an inter-vehicle distance detecting means for detecting an inter-vehicle distance between a host vehicle and a preceding vehicle. A target inter-vehicle distance setting means for setting a target inter-vehicle distance between the host vehicle and the preceding vehicle, and an inter-vehicle distance for performing speed control of the host vehicle such that the inter-vehicle distance between the host vehicle and the preceding vehicle matches the target inter-vehicle distance. In the inter-vehicle distance control device including the control means, the following vehicle traveling state detecting means for detecting the traveling state of the following vehicle, and the following vehicle traveling state detecting means for detecting the traveling state of the following vehicle when stopped A target inter-vehicle distance is set and a target inter-vehicle distance set by the target inter-vehicle distance setting means is changed so that the inter-vehicle distance when the host vehicle is stopped becomes the target inter-vehicle distance when the vehicle is stopped. Change target distance It is characterized in that it comprises a stage, a.

In the inter-vehicle distance control device according to a second aspect of the present invention, the target inter-vehicle distance changing means sets the target inter-vehicle distance set by the target inter-vehicle distance setting means to a change value of the target inter-vehicle distance when the vehicle is stopped. It is characterized in that the target inter-vehicle distance is changed so as not to fall below. Further, in the inter-vehicle distance control device according to claim 3, the target inter-vehicle distance changing means is
When it can be considered that there is no following vehicle based on the running state of the following vehicle detected by the following vehicle running state detection means, or when there is a following vehicle and the following vehicle is accelerating and approaching. When it is determined that the target inter-vehicle distance is changed, the target inter-vehicle distance is changed.

Further, in the inter-vehicle distance control device according to a fourth aspect of the present invention, the target inter-vehicle distance changing means sets the target inter-vehicle distance when the stop is set by the target inter-vehicle distance setting means. The target inter-vehicle distance is changed so as to be larger than the above. This claim 1
In the invention described in any one of claims 1 to 4, the traveling state of the following vehicle is detected. Then, in accordance with this traveling state, a change value of the target inter-vehicle distance at the time of stop is set, and the inter-vehicle distance when the own vehicle stops becomes the change value of the target inter-vehicle distance at the time of stop, so that the target inter-vehicle distance is changed. The target inter-vehicle distance set by the distance setting means is changed. For example, the target inter-vehicle distance is changed so that the target inter-vehicle distance set by the target inter-vehicle distance setting means does not fall below the change value of the target inter-vehicle distance when stopped.

Then, for example, when it is determined that there is no following vehicle, or when there is a following vehicle and the following vehicle is accelerating and approaching the host vehicle, the target inter-vehicle distance is changed. Be seen. Then, for example, as a change value of the target inter-vehicle distance when stopped, a value larger than the target inter-vehicle distance set by the target inter-vehicle distance setting means is set,
The target inter-vehicle distance set by the target inter-vehicle distance setting means is changed so that the inter-vehicle distance at the time of the stop becomes the change value of the target inter-vehicle distance at the time of the stop, and, for example, more than the preset target inter-vehicle distance. It is changed to a large value.

Therefore, for example, when the trailing vehicle is traveling at the end of a traffic jam on a highway and there is no following vehicle, or when the following vehicle is accelerating and approaching, this is detected by the following vehicle running state detecting means. And accordingly,
Since the target inter-vehicle distance is changed to a larger value, a sufficient inter-vehicle distance with the preceding vehicle when the vehicle stops at the end of the traffic jam is secured. Therefore, it is possible to avoid giving an occupant anxiety about a secondary collision.

Further, in the inter-vehicle distance control device according to a fifth aspect, when the target inter-vehicle distance changing means detects the presence of a following vehicle after the own vehicle is stopped, the target inter-vehicle distance changing means is operated when the own vehicle starts when the preceding vehicle starts. The feature is that the target inter-vehicle distance is returned to the target inter-vehicle distance before the change. In the invention according to claim 5, the target inter-vehicle distance changing means detects the presence of the following vehicle after the own vehicle has stopped, when the own vehicle starts with the start of the preceding vehicle, The inter-vehicle distance is returned to the target inter-vehicle distance before the change. Therefore,
The vehicle-to-vehicle distance with the preceding vehicle will return to the normal target vehicle-to-vehicle distance as the vehicle starts.

According to a sixth aspect of the present invention, there is provided an inter-vehicle distance control device including a road environment detecting means for detecting a road environment of a road around the subject vehicle, and the target inter-vehicle distance changing means is the following vehicle running state detecting means. The target inter-vehicle distance is changed based on the detected traveling state of the following vehicle and the road environment of the surrounding road of the own vehicle detected by the road environment detection means.

Further, in the inter-vehicle distance control device according to a seventh aspect of the present invention, the target inter-vehicle distance changing means has the vehicle over the vicinity of a curve or the top of an uphill road based on the road environment detected by the road environment detecting means. When it is predicted that the vehicle will stop in the vicinity, based on the current position of the vehicle and the road environment, a position where the vehicle is easily visible from the following vehicle is estimated, and the target inter-vehicle distance is changed so as to stop at that position. It is characterized by that.

According to the sixth and seventh aspects of the present invention, the road environment detecting means detects the road environment of the surrounding road of the own vehicle, and the target inter-vehicle distance changing means detects the following vehicle traveling state detecting means. The target inter-vehicle distance is changed based on the traveling state of the vehicle and the surrounding road environment of the vehicle detected by the road environment detecting means. For example, when it is predicted that the host vehicle will stop near a curve or near the summit of an uphill road based on the road environment detected by the road environment detection means, the host vehicle will be stopped based on the current position of the host vehicle and the road environment. The position where the vehicle is easily visible from the following vehicle is estimated, and the target inter-vehicle distance is changed so as to stop at this position.

Therefore, by changing the target inter-vehicle distance according to the road environment, the vehicle can be stopped at a position in consideration of the road environment, and the passengers can feel secure. The inter-vehicle distance control device according to claim 8 is
An information presenting means for presenting information to an occupant is provided, and the inter-vehicle distance changing means, when changing the target inter-vehicle distance,
It is characterized in that the change is presented by the information presenting means.

In the invention according to the eighth aspect, when the target inter-vehicle distance is changed, the notification of the change of the target inter-vehicle distance is given by the information presenting means, for example, by a speaker or displayed on the display. Etc. for crew members. Therefore, the occupant can recognize that the target inter-vehicle distance has been changed by the information presenting means.

Further, the inter-vehicle distance control device according to a ninth aspect is characterized in that the target inter-vehicle distance changing means lights a hazard lamp when the target inter-vehicle distance is changed. In the invention according to claim 9, the hazard lamp is turned on when the target inter-vehicle distance is changed. Therefore, for the following vehicle,
It becomes possible to call attention.

Further, in the inter-vehicle distance control device according to the present invention, the road environment detecting means detects the current position of the own vehicle and detects road information around the own vehicle based on map information stored in advance. It is characterized in that it is processing means or information receiving means for receiving information on the road surface condition in front of the own vehicle from the information providing device. Further, claim 1
In the inter-vehicle distance control device according to No. 1, the following-vehicle traveling state detecting means detects the inter-vehicle distance to the following vehicle by using at least one of a millimeter wave radar, a laser radar, a stereo camera, and an ultrasonic sensor. It is characterized by that.

[0022]

According to the inter-vehicle distance control device of the first aspect of the present invention, the inter-vehicle distance to the preceding vehicle at the time of stop can be changed according to the traveling state of the following vehicle. Further, according to the inter-vehicle distance control device of the second aspect, the target inter-vehicle distance is changed so that the target inter-vehicle distance set by the target inter-vehicle distance setting means does not fall below the change value of the target inter-vehicle distance when stopped. This makes it possible to easily and accurately change the target inter-vehicle distance.

Further, according to the inter-vehicle distance control device of the third and fourth aspects, when it can be considered that there is no following vehicle, or when there is a following vehicle and the following vehicle accelerates and approaches. When it is determined that the target inter-vehicle distance is changed, for example, the change value of the target inter-vehicle distance when stopped is set to be larger than the target inter-vehicle distance when stopped set by the target inter-vehicle distance setting means. By making a change, the vehicle can be stopped with a sufficient inter-vehicle distance when it is stopped at the end due to traffic jam or the like, or when the following vehicle is accelerating and approaching.

Further, according to the inter-vehicle distance control device of the fifth aspect, when the presence of a following vehicle is detected after the own vehicle is stopped, the changed target inter-vehicle distance is set when the own vehicle starts when the preceding vehicle starts. Because it returns to the target inter-vehicle distance before the change,
It is possible to return the inter-vehicle distance to the preceding vehicle to the target inter-vehicle distance before the change as the vehicle starts. Further, according to the inter-vehicle distance control device according to claims 6 and 7, it is predicted that, for example, the host vehicle will stop near a curve or near the top of an uphill road based on the road environment detected by the road environment detection means. In this case, the target inter-vehicle distance is changed so that the own vehicle stops at a position where it can be easily seen from the following vehicle, so that the vehicle can be stopped at a position in consideration of the road environment, and the passengers can feel secure.

According to the inter-vehicle distance control device of the eighth aspect, when the target inter-vehicle distance is changed, the occupant is notified that the target inter-vehicle distance is changed. The occupant can be made aware that the change has been made. Further, according to the inter-vehicle distance control device of the ninth aspect, since the hazard lamp is turned on when the target inter-vehicle distance is changed,
You can call attention.

According to the inter-vehicle distance control device of the tenth aspect, the road environment detecting means detects the current position of the own vehicle and detects road information around the own vehicle based on map information stored in advance. Since the information processing means or the information receiving means for receiving the information about the road surface condition in front of the own vehicle from the information providing device is used, the road environment around the own vehicle can be easily recognized.

Further, according to the inter-vehicle distance control device of the eleventh aspect, at least one of a millimeter wave radar, a laser radar, a stereo camera and an ultrasonic sensor is used as the following vehicle running state detecting means. Therefore, the inter-vehicle distance to the following vehicle can be detected easily and accurately.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described. FIG. 1 is a system configuration diagram showing an embodiment of a vehicle including a preceding vehicle following travel control device to which an inter-vehicle distance control device of the present invention is applied. This vehicle has rear wheels 1R
A rear-wheel drive vehicle in which L and 1RR are drive wheels and front wheels 1FL and 1FR are driven wheels, and the drive torque of the engine 2 is transmitted to the rear wheels 1RL and 1RR via the automatic transmission 3.

The rotation state, torque, output, etc. of the engine 2 can be controlled by the engine control unit 11.
Specifically, by adjusting the throttle valve opening, the idle valve opening, the ignition timing, the fuel injection amount, the fuel injection timing, etc., the rotation state of the engine 2, torque,
The output etc. can be controlled. Further, the automatic transmission 3 can be controlled by the transmission control device 12. Specifically, by adjusting the working fluid pressure supplied to the clutches and brakes in the automatic transmission 3, it is possible to change the selected gear ratio and obtain the desired reduction ratio.

Further, each of the wheels 1FL to 1RR is a wheel cylinder 4F which constitutes a so-called disc brake.
Equipped with L to 4RR. This wheel cylinder 4FL
~ 4RR depends on the braking fluid pressure supplied to each wheel 1FL
The braking force is applied to 1RR. The braking force applied to each of the wheels 1FL to 1RR can be controlled by the braking fluid pressure control device 13. Specifically, for example, by increasing the braking fluid pressure like a driving force control device (TCS) or reducing the braking fluid pressure like an anti-skid control device (ABS), each wheel cylinder 4FL can be reduced. Adjusting the braking fluid pressure to ~ 4RR, each wheel 1F
The braking force to L to 1RR can be controlled. In addition,
The brake fluid pressure regulated in the brake fluid pressure control device 13 is supplied from the master cylinder 22 which is boosted by depressing the brake pedal 21.

Each of these control devices controls the traveling state of the vehicle, and as a result, the traveling state can be controlled by adjusting the acceleration / deceleration of the vehicle, the longitudinal speed, and the like. These control devices can operate independently, but as a whole function, they are controlled by the automatic travel control device 10 including the inter-vehicle distance control and the preceding vehicle following travel control. The automatic travel control device 10 performs various arithmetic processes to control the traveling state of the vehicle, and performs inter-vehicle distance control, preceding vehicle following traveling control, and the like.

Further, the vehicle is equipped with a laser radar and the front inter-vehicle distance sensor 15 for detecting the inter-vehicle distance to the preceding vehicle.
A rear inter-vehicle distance sensor 16 equipped with a laser radar for detecting an inter-vehicle distance to a following vehicle, and wheels 1FL to 1R.
A wheel speed sensor 17 for detecting the rotational speed of R, an acceleration sensor 18 for detecting longitudinal and lateral accelerations generated in the vehicle,
A braking fluid pressure sensor 19 for detecting the braking fluid pressure, and an accelerator opening sensor 20 for detecting the depression amount of the accelerator pedal.
Is equipped with. Further, this vehicle is equipped with a manual switch 9 for adjusting the traveling state of the own vehicle by manual input by the driver. Further, this vehicle is provided with a display and a speaker 23 for presenting the control contents of the automatic traveling control device 10 to an occupant, particularly a driver.

Further, this vehicle is equipped with a navigation system 7 which detects the current position of the own vehicle by GPS and retrieves the surrounding information of the own vehicle based on the map information stored in advance. In this navigation system 7, the position Xn of the host vehicle and, as shown in FIG. 2, curvature information (αs) and road gradient information (θs) in front of the vehicle.
Is held for each data point DP set arbitrarily, and curvature information (αs) and road gradient information (θ) in front of the vehicle are held.
The distance Lms on the map data between s) and the immediately previous data point is transmitted to the automatic travel control device 10.

Next, the calculation processing of the inter-vehicle distance control performed in the automatic cruise control device 10 will be described with reference to the flowchart of FIG. This arithmetic processing is executed by a timer interrupt at every predetermined sampling time ΔT set to, for example, about 10 [msec] when automatic traveling is selected by a manual switch (not shown). In this flowchart, steps for communication are not particularly provided, but the result obtained by the arithmetic processing is updated and stored in the storage device at any time, and
Necessary information and programs are read from the storage device at any time. The engine control device 11, the transmission control device 12, and the braking fluid pressure control device 13 communicate with each other as needed, and necessary information and commands are bidirectionally exchanged.

In this calculation process, first, in step S1, the longitudinal acceleration Xg detected by the acceleration sensor 18, the lateral acceleration Yg, the wheel speeds Vw _{FL to} Vw _RR detected by the wheel speed sensor 17, and the accelerator opening degree. Accelerator opening degree Acc detected by the sensor 20, the braking fluid pressure sensor 1
9, the braking fluid pressure Pm detected by 9, the set speed Vc set by the manual switch 9, the front inter-vehicle distance Lfx detected by the front inter-vehicle distance sensor 15, and the rear inter-vehicle distance detected by the rear inter-vehicle distance sensor 16. Read each Lrx. The front inter-vehicle distance sensor 15 and the rear inter-vehicle distance sensor 16 set an upper limit set value L _LIM (for example, about 255 [m]) when a preceding vehicle or a following vehicle does not exist within a predetermined distance in front of or behind the own vehicle. Output.

Further, from the navigation system 7, the current position Xn of the own vehicle (n represents calculation timing),
A road curvature αs and a road gradient θs, which are road environment information around the vehicle, are read and stored in a storage area (not shown). The curvature αs and s of the road gradient θs are data numbers and depend on the data interval of the road map data held by the navigation system 7. Here, the road curvature αs and the road gradient θs are values retrieved from the data in front of the own vehicle in the road map data, and are the amount of movement Xms of the forward direction of the vehicle based on the position Xn of the own vehicle. Functions, αs = f (Xms) and θs = h (Xm
s).

Next, the process proceeds to step S2 and the
Wheel speed Vw read in step S1 _FL~ Vw_RROut of
Front left and right wheel speed Vw which is a driven wheel_FL, Vw_FRFrom the average value of
The traveling speed V of the host vehicle is calculated. Next, in step S3
After the transition, with the preceding vehicle read in step S1
This time's value of inter-vehicle distance Lfx_(n)And the previous value Lfx_(n-1)
The difference value between and is divided by the predetermined sampling time ΔT,
The relative speed dLfx between the own vehicle and the preceding vehicle is calculated. same
The following vehicle read in step S1
Current value Lrx of vehicle distance_(n)And the previous value Lrx_(n-1)With
Divide the difference value by the predetermined sampling time ΔT to obtain the
The relative speed dLrx between the two and the following vehicle is calculated.

Next, in step S4, the reference target inter-vehicle distance Lc ₀ is calculated based on the following equation (1) according to the traveling speed V of the host vehicle calculated in step S2. Lc ₀ = Kv1 × V + Kv2 (1) Note that Kv1 and Lv2 in the equation are control constants. Note that Kv2 represents the target inter-vehicle distance when the vehicle is stopped in the normal inter-vehicle distance control.

Further, in the first embodiment,
Although the reference target inter-vehicle distance Lc ₀ is calculated based on the vehicle speed V of the host vehicle, the inter-vehicle distance may be set by the driver using a manual switch. Specifically, for example, the driver can set three levels of long, medium, and short, and the control constant of the equation (1) is changed according to the level set by the driver to obtain the reference target inter-vehicle distance. Lc ₀
May be changed.

Then, the process proceeds to step S5, and based on the vehicle speed V calculated in step S2 and the rear inter-vehicle distance Lrx from the rear inter-vehicle distance sensor 16, the presence / absence of a following vehicle, the approaching state of the following vehicle, and the following vehicle are determined. Whether or not there is a possibility of being captured is determined, and whether or not control for changing the inter-vehicle distance at the time of stopping is performed is determined. The presence / absence of the following vehicle is determined based on whether or not the rear inter-vehicle distance Lrx is the limit value L _LIM . When Lrx = L _LIM, it is determined that there is no following vehicle. Further, the determination of the approaching state is performed by determining the relative speed dL with the following vehicle calculated in step S3.
rLax is equal to or more than a threshold value dLa (for example, about 4 [m / s ² ]) for determining whether the following vehicle is accelerating and approaching, and dLa ≦ dLrx
When it is, it is determined that the vehicle is accelerating.

Further, whether or not there is a possibility of capturing the following vehicle is determined by the sum ΣLrx of the latest m rear vehicle distances Lrx based on the past history, and the limit value L of the rear vehicle distance Lrx.
It performed depending on whether or not equal to m times the _{LIM, ΣLrx} ≠
When m × L _LIM, it is determined that the following vehicle may be captured. When there is a following vehicle and the following vehicle is accelerating and approaching, that is, Lrx ≠ L
_{When LIM} and dLa> dLrx, the control standby flag Fsby is set to Fsby = ON. Conversely, when there is a following vehicle, but this following vehicle is not accelerating and approaching, that is, Lrx ≠ L _LIM and dLa ≦ dLrx
If it is, the control standby flag Fsby is set to Fsby.
= Set to OFF.

On the other hand, there is no following vehicle and the following vehicle
When there is no possibility to capture, that is, Lrx = L_LIM
And ΣLrx = m × L_LIMControl stun when
Bye flag Fsby is set to Fsby = ON. On the contrary
No vehicle exists, but may catch a following vehicle
Case, that is, Lrx = L_LIMAnd dLrx ≠ m × L
_LIMWhen, the following vehicle is detected in the past m times.
The following vehicle at the latest point in time m1 is approaching acceleration
Whether the relative vehicle speed dLrx (m1) is
It is determined whether dLrx (m1) <dLa.

When dLrx (m1) <dLa, the control standby flag Fsby is set to Fsby = ON because there is a possibility of catching the following vehicle. On the other hand, when dLrx (m1) ≧ dLa, the control standby flag Fsby is set to Fsby = OFF because there is no possibility of capturing the following vehicle. In other words, if there is a traffic jam on an expressway, for example, and if there is no following vehicle, the vehicle will be at the end of the traffic jam when the vehicle decelerates. Make a decision to increase the inter-vehicle distance. On the other hand, if there is a following vehicle, or if there is a following vehicle until a while ago and there is a possibility of catching it in the future, when the vehicle slows down, the vehicle is still in a traffic jam. Therefore, the inter-vehicle distance to the preceding vehicle may remain the reference target inter-vehicle distance Lc ₀ , except when the following vehicle is accelerating and approaching.
However, when the following vehicle is accelerating and approaching,
When the vehicle decelerates, it may collide with the vehicle itself, so it is determined to increase the inter-vehicle distance to the preceding vehicle.

Then, in step S6, the curvature of the road,
The surrounding road environment is judged using the navigation system 7 having a database of road gradients and the like. That is, based on the curvature αs and the road gradient θs at each data point DPs in the front of the vehicle searched from the road map data, the point where the curvature of the curve in the front of the vehicle is maximum or the point where the road gradient is maximum is detected. To do. Then, the area past the maximum value point in front of the vehicle is set as a blind spot possibility area where the own vehicle is less visible to the following vehicle, and the own vehicle stops in this blind spot possibility area from the running state of the own vehicle. If it is predicted that there is a possibility of stopping, and if it is predicted that there will be a stop, set the vehicle-to-vehicle distance at the time of stopping according to the predicted stop position in the blind spot possibility area. .

Specifically, first, based on the curvature information (αs) in front of the vehicle and the road gradient information (θs), the point at which the curvature of the curve closest to the front of the vehicle is maximum or the gradient of the nearest slope is determined to be maximum. Specify the point. That is, αi ≧ αi
When −1 and αi <αi + 1, αi at this time is set as the maximum value αmax of curvature. Similarly, θj ≧ θj−1,
Further, when θj <θj + 1, θj at this time is set as the maximum value θmax of the road gradient.

This search is performed in the following procedure. First, each data point DPs from the navigation system 7
First, the data point DP closest to the current position of the host vehicle on the road map data is specified based on the curvature αs and the road gradient θs at, for example, this data point DPs.
Is DPs ₀ (FIG. 2). Then, using this closest data point DPs ₀ as a reference, this data point D
Curvature .alpha.s ₀ and road gradient [theta] s ₀ in ps _0, curvature .alpha.z ₀ data number z = z _0, and a road gradient [theta] z _0.
Then, the data point D corresponding to the current position of the own vehicle
The curvature αs and the road gradient θs at the data point DPs in front of Ps ₀ are the curvature αz and the road gradient θ having the data number z based on the data point DPs _0.
Replace with z. That is, as the data point is located ahead of the data point DPs ₀ , the data number z
The data number z is assigned so that

Since the position of each data point DPs depends on the data interval Lms of the road map data held by the navigation system 7, the data number z also depends on the data interval of the road map data. It will be. Then, with respect to the curvature αz and the road gradient θz of the data number z set in this way, the curvature and the road gradient information of z = z ₀ are sequentially searched in ascending order of the data number z, that is, the vehicle front direction is sequentially searched. Then, the latest αmax and θmax that satisfy the above conditions are determined.

The data number i corresponding to the curvature αi when it becomes αmax is a value corresponding to the distance from the data point DPz ₀ corresponding to the current position of the host vehicle. Therefore, the maximum value αi of curvature in the vehicle front direction based on the current position of the host vehicle is expressed as a function of the distance Xmi between the current position of the host vehicle and a point at which αmax is reached (αi = f (Xmi)). You can Similarly, the road gradient θj in the forward direction of the vehicle based on the current position of the host vehicle is a function of the distance Xmj (θj =
f (Xmj)).

Here, the movement amount from the current position of the host vehicle to the point of αmax, that is, the distance Xmi corresponds to each data of the data number z = i when the data number z = z ₀ to αmax, Data point D of road map data
It can be represented by a value obtained by adding the actual distance Lms between Ps for each data number z, that is, Xmi = ΣLms. Similarly,
The amount of movement X from the current position of the host vehicle to the point where θmax is reached
mj is the actual distance L between the data points of the road map data
ms can be represented by Xmj = ΣLmz, which is a value obtained by adding ms for each data number z until the data number z = j when the data number z becomes θmax from the current position z = z ₀ .

Next, starting from the point where the curvature α or the road gradient θ set in this way is the maximum, the area in front of this point and the blind spot possibility area where the host vehicle is hard to see from the following vehicle Set as. First, the start position Xnear of the blind spot possibility area is set. This sets the smaller one of the movement amount Xmi to the point where the curvature in front of the vehicle becomes αmax and the movement amount Xmj to the point where the road gradient in front of the vehicle becomes θmax, as described above.

Next, the end position Xfar of the blind spot possibility area is set. When Xnear = Xmi, it is set based on the following equation (2), and when Xnear = Xmj, the following equation (3) is set.
Set based on. Xfar = Xnear + p (αmax) (2) Xfar = Xnear + q (θmax) (3) where p (αmax) is the curvature blind spot area length set by the function of the curve curvature, Maximum value αma
A value that changes according to x. Similarly, q (θmax
) Is a road gradient blind spot area length set by a function of the road gradient, and is a value that changes according to the maximum value θmax of the road gradient.

The curvature blind spot area length p (αmax) becomes longer as the maximum value αmax of the curvature of the curve increases, as shown in FIG.
(Αmax) is also set to be large, and when the maximum value αmax of the curvature is equal to or less than the threshold value α ₁ , the target inter-vehicle distance Kv2 at the time of stopping in the above-described normal inter-vehicle distance control becomes the maximum value αmax of the curvature. When it becomes larger than the threshold value α ₁ , it increases non-linearly as the maximum value α max increases. When the maximum value αmax of the curvature exceeds a threshold value α ₂ which is larger than the threshold value α ₁ , the curvature blind spot area length p
The maximum value pmax of (αmax) is set.

Similarly, the road gradient blind spot area length q (θma
x) is, for example, as shown in FIG.
Since the blind spot area becomes longer as max increases, the road gradient blind spot area length q (θmax) is set to be larger,
When the maximum value θmax of the road gradient is less than or equal to the threshold value θ ₁ , the target inter-vehicle distance Kv2 at the time of stopping in the above-described normal inter-vehicle distance control becomes, and the maximum value of the curvature θ max is larger than the threshold value θ _1. When the value exceeds θ ₂ , the maximum value qmax of the road gradient blind spot area length q (θmax) is set.

Next, it is determined from the running state of the host vehicle whether or not there is a possibility of stopping in the blind spot possibility area.
Letting Xa be an estimated stop position based on the current position predicted from the running state of the host vehicle, if Xa ≧ Xnear and Xa <Xfar, there is a possibility of stopping in the blind spot possibility area. judge. On the contrary, when Xa <Xnear and Xa ≧ Xfar, it is determined that there is no possibility of stopping in the blind spot possibility area.

The estimated stop position Xa is estimated based on the vehicle speed V calculated in step S2 and the target acceleration Xgs calculated at the previous calculation timing. And
When it is determined that there is a possibility of stopping in the blind spot possibility area, it is considered that the surrounding environment should be taken into consideration when setting the inter-vehicle distance with the preceding vehicle at the time of stop, and the environment flag Fkan is set to F.
When kan is set to ON and it is determined that there is no possibility of stopping in the blind spot possibility area, the environment flag Fkan is set to Fkan = OFF because it is not necessary to consider the surrounding environment.

The search for the maximum curvature position and the maximum road gradient position in front of the vehicle is performed, for example, for the number of data corresponding to a preset vehicle front distance. And
As a result of searching for a predetermined number of data, when the maximum curvature position and the maximum road gradient position cannot be specified, that is, when the road ahead of the vehicle is a straight road or the road surface has no road gradient, etc. Therefore, it is not necessary to consider the surrounding environment.

In the search for the maximum curvature value and the maximum road gradient value, when the data number is larger than the previous curvature or road gradient, and the data number is larger than the next curvature or road gradient. The case where the curvature of the data number and the road gradient are specified as the maximum value is described above. However, for example, when there are a plurality of data numbers satisfying these in the search target data, it is applicable. It is determined whether or not the surrounding environment needs to be considered for all things, and among those that are determined to need to consider the surrounding environment, the one with the closest blind spot start position to the own vehicle can be blind spotted. Start position of the sex area Xnear
Should be set as.

Then, the process proceeds to step S7, and the target inter-vehicle distance Lcstop at the time of stop is set according to the environment flag Fkan. In other words, the environment flag is Fkan = OFF,
If your vehicle is at the end of the traffic jam on a straight road, etc.,
Since it is not necessary to consider the surrounding environment, the target vehicle distance during stop Lcstop is set to a constant value, and the preset control constant Lcst is set.
Op ₀ is set as the target inter-vehicle distance Lcstop at the time of stop. The control constant Lcstop ₀ is a value larger than the target inter-vehicle distance Kv2 at the time of stopping during normal traveling (Lcstop 0
> Kv2).

On the other hand, the environment flag is Fkan = ON,
When the road is curved or has a slope, the stop target inter-vehicle distance Lcstop is set according to the surrounding environment.
That is, the estimated stop position X predicted from the current traveling state
The difference between a and the starting point Xnear of the blind spot possibility area is added to the target inter-vehicle distance Kv2, and this is added to the target inter-vehicle distance at stop Lcstop.
And That is, the target inter-vehicle distance is made longer than the target inter-vehicle distance Kv2 at the time of normal stop, and the vehicle is stopped at the starting point Xnear of the blind spot possibility area that is easy to see from the following vehicle.

It should be noted that a limit value may be set for the target vehicle distance during stop Lcstop to prevent the target vehicle distance during stop Lcstop from becoming too large. Next, in step S8, the target inter-vehicle distance correction value Lch is set. Here, the larger of the reference target inter-vehicle distance Lc ₀ calculated in step S4 and the target inter-vehicle distance Lcstop set in step S7 is set as the target inter-vehicle distance correction value Lch.

Then, the process proceeds to step S9, and the target inter-vehicle distance Lc is set. That is, in step S5, Fsby
= OFF, there is a following vehicle, and the following vehicle is not accelerating and approaching, the reference target inter-vehicle distance Lc
₀ is set as the target inter-vehicle distance Lc. Conversely, if Fsby = ON is set in step S5 and there is no following vehicle, or if there is a following vehicle and the vehicle is accelerating and approaching, the target inter-vehicle distance correction value Lch is set to the target inter-vehicle distance Lc.
Set as. At this time, the target inter-vehicle distance correction value Lch
= Lcstop, a first-order lag filter is applied to prevent a sudden change in the target inter-vehicle distance, and Lc = L
ch / (1 + τs).

Then, the process proceeds to step S10 to calculate the target vehicle speed Vs. Here, it is calculated according to the following equation (4) based on the set vehicle speed Vc, the front inter-vehicle distance Lfx, and the relative speed dLfx with the preceding vehicle. Note that Kl in the formula
p and Kld are control gains. In addition, Mid [a,
b, c] represents a function that takes an intermediate value between a, b, and c.

Vs = Mid [Vc, (V + dLfx) + Klp. (Lx-Lc) + Kld.dLfx, 0] (4) Then, the process proceeds to step S11 to calculate the target acceleration Xgs. That is, from the difference value between the target vehicle speed VS calculated in step S10 and the traveling speed V of the host vehicle calculated in step S2, for example, PID (proportional-integral-derivative)
Calculated by control.

Then, the process proceeds to step S12, where the target acceleration Xgs calculated in step S11 is negative,
That is, when deceleration is required, the target acceleration Xgs
Is multiplied by a brake specification coefficient or a value obtained by multiplying the braking fluid pressure Pm read in step S1 by the brake specification coefficient is set as the target braking fluid pressure Pws _j . The brake specification coefficient is, for example, a coefficient determined by the coefficient of friction between the disc rotor and pad of each wheel, the wheel cylinder cross-sectional area, the disc rotor effective diameter, the tire rolling radius, and the like.

Next, in step S13, when the target acceleration Xgs calculated in step S11 is positive, that is, when acceleration is required, a value obtained by multiplying the target acceleration Xgs by a drive system parameter and Of the values obtained by multiplying the accelerator opening Acc read in step S1 by the drive system specification variables, whichever is larger is calculated as the target drive torque Tes. The drive system specification variables are variables that are determined by, for example, gear inertia, reduction ratio, transmission efficiency, engine characteristics, and the like.

Next, in step S14, the target braking fluid pressure Pws _j and the target driving torque Tes calculated in step S13 are directed to the braking fluid pressure control device 13, the engine control device 11, and the transmission control device 12. In addition to the output, the information presentation signal of the target inter-vehicle distance control is output to the display and the speaker 23, and then the main program is restored. This display and information presentation by the speaker 23 are performed by, for example, setting the target inter-vehicle distance Lc in step S9 as the target inter-vehicle distance correction value Lch / (1 + τs)
When is set, it is the end of the traffic jam and the target inter-vehicle distance is changed to make the inter-vehicle distance wider than usual. For example, “It is the last end of the traffic jam. The inter-vehicle distance at the stop is widened. , Etc. by voice or displayed on the display.

Next, the operation of the first embodiment will be described. FIG. 6 is a timing chart showing an example of the operation state, in which (a) is the vehicle speed V _{F of the} preceding vehicle and (b) is the vehicle speed.
Is the vehicle speed V of the host vehicle, (c) is the environment flag Fkan, (d)
In, the solid line represents the target inter-vehicle distance Lc, the alternate long and short dash line represents the reference target inter-vehicle distance Lc ₀ , and the broken line represents the set value of the target inter-vehicle distance Lc at the time of stopping, which is set at each time point.

Further, in (e), the solid line represents the target inter-vehicle distance Lc by the conventional inter-vehicle distance control device, and the broken line is
This is a value set as the target inter-vehicle distance when the vehicle is stopped in the conventional inter-vehicle distance control device. Now, when the host vehicle is traveling at a constant speed following the preceding vehicle on a highway or the like, and the following vehicle is running without accelerating and approaching, the following vehicle exists, but accelerating and approaching the own vehicle. Therefore, the control standby flag Fsby is set to Fsb in the process of step S5.
y = OFF is set, and the process proceeds to step S9. Then, the reference target inter-vehicle distance Lc ₀ calculated based on the equation (1) in the process of step S4 is set as the target inter-vehicle distance Lc, and the inter-vehicle distance to the preceding vehicle detected by the front inter-vehicle distance sensor 15 is set to the reference target. The braking fluid pressure control device 13 or the engine control device 1 so as to match the inter-vehicle distance Lc _0.
1. A control signal for controlling the transmission control device 12 is generated and output.

As a result, the host vehicle travels following the preceding vehicle while maintaining the following distance according to the host vehicle speed. At this time, as the target inter-vehicle distance Lc, the reference target inter-vehicle distance Lc ₀
Is set, Kv2 is set as the target inter-vehicle distance when the vehicle is stopped, as shown in FIG. 6 (d).

When the following vehicle starts accelerating and approaching at this time t ₁ from this state, the control standby flag Fsby is set to Fsby = ON in step S5, and the process proceeds to step S6. Then, based on the curvature and road gradient information of the road around the own vehicle from the navigation system 7, the curvature and road gradient information of the road toward the front of the own vehicle in the order of data number z based on the current position Xn of the own vehicle. It is updated and searched to identify a point in front of the host vehicle having the maximum curvature and a point having the maximum road gradient. It should be noted that this search is performed until the data number z corresponding to a preset distance in front of the vehicle is reached.

At this time, when the vehicle is traveling on a substantially straight road and on a road having almost no gradient, the maximum curvature and the maximum road gradient are substantially zero, so the surrounding road environment is The environment flag Fkan is set to F because it does not need to be considered.
After setting kan = OFF, the process proceeds to step S7, and the target vehicle distance during stop Lcstop is calculated. In this case, since the environment flag is Fkan = OFF, a preset control constant Lcstop ₀ is set as the target vehicle distance during stop Lcstop.

[0072] Then, the process shifts to step S8, but calculates the target inter-vehicle distance correction value Lch, in this case, the reference vehicle distance Lc ₀ because stopped vehicle distance Lcstop is smaller than the reference target inter-vehicle distance Lc ₀ The target inter-vehicle distance correction value Lch is set, and then the process proceeds to step S9 to set the reference target inter-vehicle distance Lc ₀ as the target inter-vehicle distance Lc.

Then, based on the target inter-vehicle distance Lc, the braking fluid pressure control device 13 or the engine control device 11,
A control signal for controlling the transmission control device 12 is generated and output. Further, since the control standby flag is set to Fsby = ON in the processing of step S5, for example, an information presenting signal for notifying the occupant that the vehicle is at the end of the traffic jam and the inter-vehicle distance is wider than usual. To the display and the speaker 23. As a result, since the information is presented on the display and the speaker 23, the occupant can recognize that the inter-vehicle distance at the time of stop is secured to be wider than usual.

In this way, since the notification that the inter-vehicle distance will be larger than usual is given, even if the inter-vehicle distance suddenly becomes longer than usual, the occupant does not feel uncomfortable. At this time, when the following vehicle is accelerating and approaching at time t ₁ , the target vehicle distance during stop Lcstop is calculated from Kv2 to the control constant Lcst.
Although it increases to op ₀ , at this time, in order to prevent the target inter-vehicle distance from changing suddenly, the target inter-vehicle distance is changed by applying a first-order lag filter.
stop is from Kv2 to L, as indicated by the broken line in FIG.
It will gradually increase to cstop ₀ .

When the preceding vehicle decelerates from this state at time t ₂ (FIG. 6 (a)), the inter-vehicle distance from the preceding vehicle decreases, so the braking fluid pressure control is performed so as to secure the reference target inter-vehicle distance Lc _0. The device 13 is controlled to decelerate the host vehicle (see FIG. 6).
(B)), and accordingly, the reference target inter-vehicle distance Lc ₀ also decreases (FIG. 6 (d)). Then, when the preceding vehicle continues to decelerate and the following vehicle also accelerates and approaches, the processes of steps S5 to S9 are continuously performed. Then, while the reference target inter-vehicle distance Lc ₀ is larger than the control constant Lcstop ₀ , the reference target inter-vehicle distance Lc ₀ is set as the target inter-vehicle distance Lc, and the inter-vehicle distance control is performed based on this. Therefore, the target inter-vehicle distance at the time of stop maintains the control constant Lcstop ₀ (FIG. 6 (d)).

From this state, when it is detected that there is a curve in front of the host vehicle in the surrounding road environment determination processing in step S6, the start position Xnear of the blind spot possibility area is determined based on the maximum value of the road curvature. Is specified. Then, the function p (αmax corresponding to the maximum value αmax of the road curvature is
) Is specified, and based on this, the end position Xfar of the blind spot possibility area is specified.

Here, the blind spot possibility area changes according to the road curvature α, but in the first embodiment, the blind spot possibility area is changed to αmax according to the maximum value αmax of the road curvature. Since the larger the larger the blind spot, the larger the blind spot possibility area can be set according to the actual blind spot possibility area. Then, the vehicle speed V and the target acceleration Xg calculated in step S11 during the previous processing
The estimated stop position Xa is estimated based on s and. At this time, the estimated stop position Xa is the start position X of the blind spot possibility area.
If the vehicle is not located between the near position and the end position Xfar, the own vehicle does not stop in the blind spot possibility area, so it is determined that the surrounding road environment need not be considered.

When the estimated stop position Xa is located between the start position Xnear and the end position Xfar of the blind spot possibility area, the own vehicle is predicted to stop within the blind spot possibility area, so that the surrounding road environment is controlled. As you need to consider
At time t ₃ , the environment flag Fkan is set as Fkan = ON (FIG. 6 (c)). Environment flag Fkan = Fkan = ON
Therefore, in the process of step S7, the value obtained by adding the difference between the estimated stop position and the start position Xnear of the blind spot possibility area to the target inter-vehicle distance Kv2 at the time of normal stop and the control constant Lcstop ₀ are set. Whichever is larger is set as the target vehicle distance during stop Lcstop. Then, for example, if the value obtained by adding the difference between the estimated stop position and the start position Xnear of the blind spot possibility area to the target vehicle distance Kv2 during normal stop is greater than the target vehicle distance during stop Lcstop, this is stopped. The time target inter-vehicle distance Lcstop is set.

Then, the larger one of the target inter-vehicle distance during stop Lcstop and the reference target inter-vehicle distance Lc ₀ , in this case,
The reference target inter-vehicle distance Lc ₀ is set as the target inter-vehicle distance correction value Lch, and the control standby flag is Fsby = ON, but the target inter-vehicle distance correction value Lch is the reference target inter-vehicle distance Lc _{0. 0} is set as the target inter-vehicle distance Lc.

At this time, if the control constant Lcstop ₀ is smaller than the value obtained by adding the target inter-vehicle distance Kv2 at the time of normal stop and the difference between the estimated stop position and the start position Xnear of the blind spot possibility area, at the time of stop The set value of the target inter-vehicle distance Lc is
From the control constant Lcstop ₀ to the target inter-vehicle distance Kv2 at the time of normal stop, the estimated stop position and the start position X of the blind spot possibility area
The value is changed to the value obtained by adding the difference of near, but at this time, it is set so as to gradually rise by performing the first-order delay processing (FIG. 6D).

When the difference between the estimated stop position Xa and the start position Xnear of the blind spot possibility area increases with the forward movement of the host vehicle, the sum of these difference and the target inter-vehicle distance Kv2 at the time of stop increases and the vehicle stops. Although the target vehicle-to-vehicle distance Lcstop increases, the target vehicle-to-vehicle distance Lcstop is limited to the upper limit value by limiting the upper limit of the target vehicle-to-vehicle distance Lcstop.

Then, the reference target inter-vehicle distance Lc₀When stopped
While the distance is larger than the target inter-vehicle distance Lcstop, the reference target inter-vehicle distance is set.
Distance Lc₀Is set as the target inter-vehicle distance Lc,
Point t _FourIs the reference target inter-vehicle distance Lc₀Is the target inter-vehicle distance when stopped
When it is less than Lcstop, the target inter-vehicle distance is determined in the process of step S8.
The target vehicle distance at stop Lcstop is set as the separation correction value Lch.
The target vehicle is
The distance Lc is set.

As a result, the target inter-vehicle distance Lc at the time of stop is obtained.
Since a value larger than the target inter-vehicle distance Kv2 at the time of normal stop is set as the stop, the host vehicle tends to decelerate to secure the target inter-vehicle distance Lcstop at the time of stop,
Changes in vehicle speed with a conventional inter-vehicle distance processing control device (Fig. 6 (a))
The speed will be reduced more quickly than
(B)).

Further, since the target inter-vehicle distance Lc is set to the filtered value of the target inter-vehicle distance correction value Lch, the display and the speaker 23 notify the end of the traffic jam and increase the inter-vehicle distance to stop. Is done. At this time, the target inter-vehicle distance Lcstop at stop is set as the target inter-vehicle distance Lc, and the target inter-vehicle distance Lcstop at stop is set so as to stop at the start position Xnear of the blind spot possibility region where the curvature becomes maximum. As shown in FIG.
The host vehicle A will stop at the maximum curvature position where the curve reaches its peak. Therefore, the host vehicle A will stop at a position where it can be easily seen from the following vehicle B, and the following vehicle B will recognize the host vehicle A when it reaches the point b.

On the other hand, in the conventional inter-vehicle distance control device, as shown in FIG. 6 (e), the reference inter-vehicle distance Lc ₀ is used as the target inter-vehicle distance Lc. Is always Kv2 regardless of the environmental conditions around the road. Therefore, the vehicle is controlled so as to stop at a position where the distance from the preceding vehicle is Kv2 regardless of the environment surrounding the road, so that the vehicle also stops at a distance between the preceding vehicle and Kv2 as shown in FIG. It will be.

In this way, when the own vehicle A stops at the point a'beyond the peak position of the curve, from the following vehicle B,
The position where the own vehicle A is stopped is difficult to see due to the curve, and the own vehicle A cannot be recognized until the point b ′ closer to the own vehicle A is reached. However, in the above-described first embodiment, the vehicle can be stopped at a position where it can be easily recognized by the following vehicle b, and the occupant can be given a sense of security.

Further, when it is determined in the determination of the surrounding road environment that the road gradient has a peak in front of the host vehicle, whether the host vehicle is predicted to stop within the blind spot possibility area due to the road gradient in the same manner. When it is predicted that the vehicle will stop within the blind spot possibility area,
The stop target inter-vehicle distance Lcstop is adjusted so as to stop at the peak position of the road gradient. Therefore, as shown in FIG. 8, the host vehicle A is near the peak position of the road gradient (point p).
Therefore, the host vehicle A will stop at a position easily visible from the following vehicle B.

On the other hand, when the inter-vehicle distance control is performed similarly to the conventional vehicle travel control device, the own vehicle stops at the inter-vehicle distance Kv2 with the preceding vehicle. As shown, the vehicle will stop at a position (point p ') that exceeds the peak of the road gradient, and the vehicle will stop at a position that is difficult to see from the following vehicle. However, in the first embodiment, as shown in FIG. 8, the host vehicle A is controlled so as to stop at the peak position (point p) of the road gradient, and therefore the following vehicle B is set as the preceding vehicle A.
It becomes possible to easily and surely recognize the passenger and to give the passenger a sense of security.

Further, for example, when the vehicle is traveling in the absence of the following vehicle, the presence / absence of the following vehicle is determined based on the history of the following distance to the following vehicle. When it is determined that there is no following vehicle in the past m times, or when there is a following vehicle but the following vehicle is present, the relative speed with the following vehicle calculated from the latest data is greater than the set value, When it is determined that the vehicle is not approaching acceleration, the control standby flag is set to F.
sby is set to ON. Then, the surrounding road environment is determined in the process of step S6. At this time, it is determined that the surrounding road environment need not be taken into consideration when the vehicle is traveling on a straight road having no slope. In this case, since the environment flag is Fkan = OFF, the target vehicle distance during stop Lcstop = Lcstop ₀ is set in step S7.

Therefore, in this state, when the host vehicle stops, Lcstop _{0, which} is longer than the vehicle distance Kv2 during normal stop, is set as the target vehicle distance during stop Lcstop. Distance between cars is Lcstop
It will stop so that it will be ₀ . Therefore, the vehicle will be stopped with a longer distance than usual, so for example, for passengers of a type that keeps a relatively long distance during a traffic jam on a highway, the second It does not give rise to the anxiety of a collision.

In the above first embodiment,
The case where the navigation system 7 is used to obtain the vehicle surrounding environment information has been described, but the present invention is not limited to this. For example, information receiving means for communicating with infrastructure equipment installed on the road side may be provided in the host vehicle to communicate with the infrastructure equipment to obtain vehicle surrounding environment information.

Here, the front inter-vehicle distance sensor 15 corresponds to the inter-vehicle distance detecting means, the processing of step S9 of FIG. 3 corresponds to the target inter-vehicle distance setting means, and the processing of steps S10 to S14 to the inter-vehicle distance control means. Correspondingly, the processing of step S5 corresponds to the following vehicle traveling state detecting means, the processing of steps S8 and S9 corresponds to the target inter-vehicle distance changing means, the processing of step S6 corresponds to the road environment detecting means, and the display and The speaker 23 corresponds to the information presenting means, and the navigation system 7 and the process of step S6 of FIG. 3 correspond to the road information processing means.

Next, a second embodiment of the present invention will be described. In the first embodiment, the navigation system 7 is used to determine whether or not to stop at a position that is difficult to see from the following vehicle when the vehicle stops following the preceding vehicle based on the vehicle surrounding environment information. However, the case where the target inter-vehicle distance at the time of stopping is changed has been described, but the inter-vehicle distance at the time of stopping may be changed based on whether or not to stop at the end of the traffic jam without using the navigation system 7. Just by setting, it is possible to give the passengers a sufficient sense of security.

FIG. 9 is a flow chart showing an example of the processing procedure of the inter-vehicle distance control in the second embodiment.
The same parts as those in the inter-vehicle distance control process according to the first embodiment shown in FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted. That is, in the second embodiment,
In the process of step S5, it is determined whether there is a following vehicle and the following vehicle is not accelerating and approaching. If there is no following vehicle, or if there is a following vehicle but accelerating and approaching, control standby After setting the flag to Fsby = ON, the process proceeds to step S7a.

In the process of step S7a, the control constant Lcstop ₀ is set as the target vehicle distance Lcstop at stop. Then, the process proceeds to step S8, and thereafter, the same processing as in the first embodiment is performed. Therefore, also in the second embodiment, when there is no following vehicle or when the following vehicle is approaching rapidly, the inter-vehicle distance is set to be relatively large. When the vehicle stops at the end, it is possible to give a sense of security to the driver who secures a relatively wide inter-vehicle distance.

Further, in the second embodiment,
Although the inter-vehicle distance is not set in consideration of the surrounding environment, when there is no following vehicle, the inter-vehicle distance when stopped is made larger than the inter-vehicle distance Kv2 when normally stopped. Therefore, even when the vehicle is stopped in a blind spot possibility area of a curve or a road gradient, it can be more easily recognized by the following vehicle as compared with the conventional case.
At this time, for example, when there is no following vehicle,
If the target inter-vehicle distance at the time of stop is set to be relatively large, it is possible to make it easier for the following vehicle to recognize even when the vehicle stops in the blind spot possibility area.

In each of the above-mentioned embodiments, when there is no following vehicle, the vehicle is stopped with a vehicle distance longer than usual. However, when the following vehicle is detected after the own vehicle is stopped, The inter-vehicle distance to the preceding vehicle may be returned to the normal inter-vehicle distance when the preceding vehicle starts. That is, when the host vehicle stops, the update of the target inter-vehicle distance Lc in step S9 is stopped, and the update of the target inter-vehicle distance Lc is started at the time when the start of the preceding vehicle is detected. Should be updated to the reference target inter-vehicle distance Lc ₀ .

At this time, for example, when traveling in the city, when stopping at a traffic light, etc., when the vehicle is stopped with a relatively large distance from the preceding vehicle, it becomes a cause of traffic congestion. Therefore, for example, when the presence of a following vehicle is recognized after stopping, a method of resetting the following distance when the preceding vehicle starts and a method of reducing the following distance when detecting the following vehicle are provided. , These are configured to be switchable by a manual switch, for example, when traveling on a highway or the like, a secondary collision is avoided by selecting a method of resetting the inter-vehicle distance when the preceding vehicle starts. When the vehicle is not traveling at a relatively high speed such as in a city, it may be possible to avoid a cause of traffic congestion by selecting a method of reducing the inter-vehicle distance to the preceding vehicle at the time when the following vehicle is detected.

Further, in each of the above-described embodiments, the change of the target vehicle distance at stop is notified to the occupant through the display and the speaker 23. At this time, the hazard lamp is further turned on. This may be done, and by doing so, the following vehicle can be made to more surely recognize the existence of the own vehicle.

Further, in each of the above-mentioned embodiments, the case where the feedback control is used for the portion for controlling the own vehicle speed based on the inter-vehicle distance from the preceding vehicle has been described, but the present invention is not limited to this. Automotive Engineering Magazine 19
A combination of feedback control and feedforward control may be applied, as described in the November 99 issue (P98 to P103, "Development of automatic inter-vehicle distance control system", Iijima et al.). That is, the present invention relates to control for changing the target inter-vehicle distance, and various control rules can be applied to control the inter-vehicle distance.

Further, in each of the above-described embodiments, the case where the traveling states of the preceding vehicle and the following vehicle are detected by using the laser radar has been described, but the present invention is not limited to this. The inter-vehicle distance to the following vehicle may be detected by using at least one of a millimeter wave radar, a stereo camera, and an ultrasonic sensor.

[Brief description of drawings]

FIG. 1 is a vehicle configuration diagram showing an example of a vehicle with a preceding vehicle following travel control provided with an inter-vehicle distance control device of the present invention.

FIG. 2 is an explanatory diagram for explaining peripheral position information transmitted from a navigation system 7.

FIG. 3 is a flowchart showing a calculation process for inter-vehicle distance control performed by the automatic cruise control device of FIG.

FIG. 4 is a characteristic diagram of a function p (αmax) for determining an end position of a blind spot possibility area at a maximum curvature position.

FIG. 5 is a characteristic diagram of a function q (αmax) for determining the end position of the blind spot possibility area at the maximum road gradient position.

FIG. 6 is a timing chart provided for explaining the operation of the first embodiment.

FIG. 7 is an explanatory diagram for explaining the operation of the first embodiment.

FIG. 8 is an explanatory diagram for explaining the operation of the first embodiment.

FIG. 9 is a flowchart showing a calculation process for inter-vehicle distance control according to the second embodiment.

[Explanation of symbols]

1FL ~ 1RR Wheel 2 engine 3 automatic transmission 4FL-4RR Wheel cylinder 7 navigation system 9 Manual switch 10 Automatic travel control device 11 Engine control unit 12 Transmission control device 13 Braking fluid pressure control device 15 Front inter-vehicle distance sensor 16 Rear distance sensor 17 Wheel speed sensor 18 Accelerometer 19 Braking fluid pressure sensor 20 Accelerator position sensor 21 brake pedal 22 Master cylinder 23 Display and speaker

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B60R 21/00 624 B60R 21/00 624B 624C 624D 624E 624G 624J 628 628C 628F F02D 29/02 301 F02D 29/02 301D G08G 1/16 G08G 1/16 E F term (reference) 3D044 AA25 AB01 AC16 AC24 AC26 AC28 AC51 AC56 AC57 AC59 AD02 AD17 AD21 AE21 3G093 AA05 BA04 BA23 CB10 DA06 DB02 DB11 DB15 DB16 DB18 DB21 EA02 EA03 EB03 EB04 FA07 FB01 5H180 AA01 CC03 CC04 CC11 CC12 CC14 FF05 FF12 FF25 FF27 FF32 LL01 LL04 LL07 LL08 LL09 LL15

Claims (11)

[Claims] 1. An inter-vehicle distance detecting means for detecting an inter-vehicle distance between a host vehicle and a preceding vehicle; a target inter-vehicle distance setting means for setting a target inter-vehicle distance between the own vehicle and a preceding vehicle; An inter-vehicle distance control device including an inter-vehicle distance control means for controlling the speed of the own vehicle so that the inter-vehicle distance between the preceding vehicle and the target inter-vehicle distance becomes equal to the target inter-vehicle distance. Means and a change value of the target inter-vehicle distance at the time of stop according to the running state of the following vehicle detected by the following vehicle running state detection means,
A target inter-vehicle distance changing means for changing the target inter-vehicle distance set by the target inter-vehicle distance setting means so that the inter-vehicle distance when the host vehicle is stopped becomes a change value of the target inter-vehicle distance when the vehicle is stopped. An inter-vehicle distance control device characterized by: 2. The target inter-vehicle distance changing means changes the target inter-vehicle distance so that the target inter-vehicle distance set by the target inter-vehicle distance setting means does not fall below a change value of the target inter-vehicle distance when the vehicle is stopped. The inter-vehicle distance control device according to claim 1, wherein: 3. The target inter-vehicle distance changing means can determine that there is no following vehicle based on the running state of the following vehicle detected by the following vehicle running state detecting means, or if the following vehicle is present. The inter-vehicle distance control device according to claim 1 or 2, wherein the target inter-vehicle distance is changed when it is determined that the following vehicle is present and is accelerating and approaching. 4. The target inter-vehicle distance changing means sets the target inter-vehicle distance so that a change value of the target inter-vehicle distance when stopped is larger than the target inter-vehicle distance when stopped which is set by the target inter-vehicle distance setting means. It is changed, The claim 1 characterized by the above-mentioned.
4. The inter-vehicle distance control device according to any one of 3 to 3. 5. The target inter-vehicle distance changing means sets the target inter-vehicle distance to the target inter-vehicle distance before the change when the presence of a following vehicle is detected after the own vehicle is stopped and when the own vehicle starts following the start of the preceding vehicle. 5. The method according to claim 1, wherein the operation is returned.
The inter-vehicle distance control device according to any one of 1. 6. A road environment detecting means for detecting a road environment of a road around the own vehicle, wherein the target inter-vehicle distance changing means has a traveling state of the following vehicle detected by the following vehicle traveling state detecting means, The inter-vehicle distance according to any one of claims 1 to 5, wherein the target inter-vehicle distance is changed based on the road environment of the surrounding road of the own vehicle detected by the road environment detecting means. Control device. 7. The target vehicle distance changing means, based on the road environment detected by the road environment detecting means, when it is predicted that the vehicle will stop near a curve or near the summit of an uphill road, 7. The inter-vehicle distance according to claim 6, wherein the target vehicle-to-vehicle distance is changed so as to estimate a position where the own vehicle can be easily seen from a following vehicle based on the current position of the vehicle and the road environment, and to stop at the position. Distance control device. 8. An information presenting means for presenting information to an occupant is provided, and the inter-vehicle distance changing means presents the change when the target inter-vehicle distance is changed. 7. The method according to claim 1, wherein
The inter-vehicle distance control device according to any one of 1. 9. The inter-vehicle distance according to claim 1, wherein the target inter-vehicle distance changing means is adapted to turn on a hazard lamp when changing the target inter-vehicle distance. Distance control device. 10. The road environment detecting means detects a current position of the own vehicle and detects road information around the own vehicle based on map information stored in advance, or a road surface condition in front of the own vehicle. The inter-vehicle distance control device according to any one of claims 1 to 9, which is information receiving means for receiving information from the information providing device. 11. The following vehicle traveling state detecting means is adapted to detect an inter-vehicle distance to a following vehicle by using at least one of a millimeter wave radar, a laser radar, a stereo camera and an ultrasonic sensor. The inter-vehicle distance control device according to claim 1, wherein: