JP2002052952A - Traveling control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure an inter-vehicular distance from a following vehicle while securing an inter-vehicular distance from a proceeding vehicle. SOLUTION: When there is no following vehicle (Step 4) or the inter-vehicular distance LR from the following vehicle is not lower than a limited backward inter-vehicular distance LR-LIM (Step 5) or the inter-vehicular distance LF from the proceeding vehicle does not exceed a limited forward inter-vehicular distance LF-LIM (Step 6), a target inter-vehicular distance LF* is set based on a vehicle speed VS (Step 15) and the vehicle speed control is carried out so that the vehicle travels with keeping a predetermined inter-vehicular distance corresponding to the vehicle speed VS. When the inter-vehicular distance LR from the following vehicle is lower than the limited backward inter-vehicular distance LR-LIM (Step 5) and the inter-vehicular distance LF from the proceeding vehicle exceeds the limited forward inter-vehicular distance LF-LIM (Step 6), 1/2 of the sum of the inter-vehicular distance LF from the proceeding vehicle and the inter-vehicular distance LR from the following vehicle is set as a target inter-vehicular distance L* (Step 10). Thus, the vehicular speed control is carried out so that the vehicle positions between the proceeding vehicle and the following vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling control device for a vehicle that recognizes a preceding vehicle and automatically travels with a certain inter-vehicle distance.

[0002]

2. Description of the Related Art Conventionally, as this type of travel control device,
Based on the own vehicle speed, the inter-vehicle distance to the preceding vehicle, the target inter-vehicle distance, the relative speed between the preceding vehicle and the own vehicle, etc., a target vehicle speed such that the inter-vehicle distance to the preceding vehicle maintains the target inter-vehicle distance is calculated. There is known a vehicle in which a braking force or a driving force is generated to control a vehicle speed so as to reach a target vehicle speed.

Further, as described in, for example, JP-A-5-105046, a relative distance between a preceding vehicle, a host vehicle, and a following vehicle is measured so that not only a preceding vehicle but also a following vehicle can collide. Control devices have been proposed to prevent this.

[0004]

However, in the vehicle described in the above publication, the deceleration of the host vehicle is higher when there is a risk that the following vehicle will collide with the host vehicle than when there is no danger. Is corrected to be small. Then, it is determined whether or not there is a risk that the own vehicle will collide with the preceding vehicle when decelerating at the corrected deceleration, and if there is a risk of collision with the preceding vehicle, apply braking at the corrected deceleration. Like that.

At this time, the deceleration is switched in accordance with the positional relationship between the following vehicle and the host vehicle, and the deceleration is switched to a total of three levels of large and small with respect to the predetermined deceleration. For this reason,
For example, if the deceleration is reduced as the following vehicle approaches, the inter-vehicle distance relationship with the following vehicle tends to be improved in an appropriate direction, but the inter-vehicle distance with the preceding vehicle is taken into account. Therefore, when the inter-vehicle distance to the preceding vehicle is actually small, the driver has to stop because the deceleration has been switched to a value smaller than the predetermined value even though the vehicle is approaching the preceding vehicle. There was a concern that it would cause discomfort.

Accordingly, the present invention has been made in view of the above-mentioned unsolved problems, and takes into consideration the distance between the preceding vehicle and the following vehicle, and the distance between the preceding vehicle and the following vehicle. It is an object of the present invention to provide a vehicular travel control device capable of minimizing a driver's discomfort by maintaining the own vehicle in an optimal positional relationship.

[0007]

According to a first aspect of the present invention, there is provided a traveling control device for a vehicle, comprising: vehicle speed detecting means for detecting a speed of the vehicle; An inter-vehicle distance target value calculating unit that calculates an inter-vehicle distance target value between the preceding vehicle and the own vehicle, and an inter-vehicle distance that detects a following inter-vehicle distance between the preceding vehicle and the own vehicle and a rear inter-vehicle distance between the following vehicle and the own vehicle. Detecting means, based on the own vehicle speed detected by the own vehicle speed detecting means so that the inter-vehicle distance detected value detected by the inter-vehicle distance detecting means is equal to or more than the inter-vehicle distance target value calculated by the inter-vehicle distance target value calculating means. Vehicle speed control means for controlling the speed of the host vehicle, wherein the vehicle speed control means detects the front inter-vehicle distance when the rear inter-vehicle distance detection value detected by the inter-vehicle distance detection means falls below a rear inter-vehicle distance threshold value. The value is the distance between vehicles ahead It is characterized by being adapted to reduce the inter-vehicle distance between the host vehicle and the preceding vehicle does not fall below the threshold.

In the invention according to the first aspect, the speed of the own vehicle is controlled so that the inter-vehicle distance between the preceding vehicle and the own vehicle is equal to or more than the inter-vehicle distance target value. At this time, the inter-vehicle distance between the own vehicle and the following vehicle is calculated based on, for example, the own vehicle speed and the speed of the following vehicle, and the following inter-vehicle distance at which the following vehicle is considered to be approaching the own vehicle. When the distance is below the threshold, the following distance between the preceding vehicle and the own vehicle is
For example, as long as the own vehicle calculated based on the own vehicle speed and the vehicle speed of the preceding vehicle and the like does not fall below the threshold value of the inter-vehicle distance in front of the vehicle that is considered not to collide with the preceding vehicle, etc. Vehicle speed control is performed so as to reduce the inter-vehicle distance therebetween.

Therefore, the vehicle speed is controlled so as to secure the distance to the following vehicle while maintaining at least the threshold value for the distance between the preceding vehicle and the preceding vehicle. The vehicle speed can be controlled to deal with the approach of the following vehicle in the secured state, avoiding a situation where there is a distance to the following vehicle but not to the preceding vehicle. It is possible to do.

The vehicle traveling control device according to a second aspect of the present invention includes a vehicle speed detecting means for detecting a speed of the vehicle, and a vehicle distance target value for calculating a vehicle distance target value between the preceding vehicle and the vehicle. Calculating means, a rear inter-vehicle distance target value calculating means for calculating a rear inter-vehicle distance target value between the following vehicle and the own vehicle,
Forward limit distance calculating means for calculating a preceding vehicle approach limit distance between the preceding vehicle and the own vehicle, a front inter-vehicle distance between the preceding vehicle and the own vehicle, and a rear inter-vehicle between the following vehicle and the own vehicle. An inter-vehicle distance detecting means for detecting a distance, and the self-vehicle speed detecting means detecting the inter-vehicle distance detecting value detected by the inter-vehicle distance detecting means so as to be equal to or more than the inter-vehicle distance target value calculated by the inter-vehicle distance target value calculating means. Vehicle speed control means for controlling the speed of the own vehicle based on the own vehicle speed, wherein the vehicle speed control means detects a rear inter-vehicle distance detected by the inter-vehicle distance detection means less than the rear inter-vehicle distance target value. And a correction means for correcting the target inter-vehicle distance to a small value within a range in which the preceding inter-vehicle distance detection value does not fall below the preceding vehicle approach limit distance.

According to the second aspect of the present invention, the vehicle distance between the preceding vehicle and the host vehicle is equal to or more than a target distance between the preceding vehicle and the host vehicle, which is a desired distance between the preceding vehicle and the host vehicle. Speed control is performed. At this time, when the inter-vehicle distance between the own vehicle and the following vehicle is less than a rear inter-vehicle distance target value that is a desired inter-vehicle distance between the following vehicle,
The vehicle speed control is performed so that the inter-vehicle distance target value is corrected to be small as long as the inter-vehicle distance between the preceding vehicle and the own vehicle does not fall below the inter-vehicle distance target value, and the inter-vehicle distance to the preceding vehicle becomes equal to or more than the corrected inter-vehicle distance target value. Done.

Therefore, the vehicle speed is controlled so as to secure the distance to the following vehicle while maintaining at least the approaching limit distance to the preceding vehicle, so that the distance to the preceding vehicle is reduced. The vehicle speed can be controlled to deal with the approach of the following vehicle in the secured state, avoiding a situation where there is a distance to the following vehicle but not to the preceding vehicle. It is also possible to reduce the distance between the preceding vehicle and the following vehicle when the following vehicle falls below the target value for the following inter-vehicle distance.
It is possible to deal with the approach of the following vehicle at an early stage.

Further, in the vehicle traveling control apparatus according to a third aspect of the present invention, the correction means may be configured such that the front inter-vehicle distance detection value is larger than the inter-vehicle distance target value and the rear inter-vehicle distance detection value is the rear inter-vehicle distance target value. When the value is smaller than the predetermined value, the target inter-vehicle distance is corrected so that the detected rear inter-vehicle distance becomes the target rear inter-vehicle distance.

According to the present invention, the inter-vehicle distance between the preceding vehicle and the own vehicle is larger than the inter-vehicle target value, and the inter-vehicle distance between the succeeding vehicle and the own vehicle is the rear inter-vehicle target value. When the distance is smaller than, that is, when the distance to the preceding vehicle is sufficient, but when the following vehicle is approaching, the target inter-vehicle distance is corrected so that the detected value between the rear inter-vehicle distance becomes the target value for the rear inter-vehicle distance. I do. That is, for example, a value obtained by subtracting the rear inter-vehicle distance target value from the sum of the front and rear inter-vehicle distance detection values is set as the inter-vehicle distance target value, and the position of the own vehicle is shifted from the preceding vehicle between the preceding vehicle and the following vehicle. The target inter-vehicle distance is corrected so as to secure the target rear inter-vehicle distance with the following vehicle.

Therefore, the vehicle speed is controlled so as to secure the target value of the rear inter-vehicle distance with the following vehicle while maintaining at least the preceding vehicle approach limit distance with the preceding vehicle. Thus, the host vehicle can be located at an appropriate position between the preceding vehicle and the following vehicle without securing the inter-vehicle distance with the following vehicle. Also,
The vehicle travel control device according to claim 4, wherein the correction means corrects the inter-vehicle distance target value in a range where the inter-vehicle distance detection value in front does not fall below the inter-vehicle distance target value. And

According to the fourth aspect of the present invention, the target inter-vehicle distance is corrected within a range in which the inter-vehicle distance to the preceding vehicle does not fall below the target inter-vehicle distance. After securing, the maximum inter-vehicle distance with the following vehicle can be ensured even if it is not the rear inter-vehicle distance target value. Further, in the vehicle traveling control device according to claim 5, the correction means sets a half of the sum of the front inter-vehicle distance detection value and the rear inter-vehicle distance detection value as the inter-vehicle distance target value. It is characterized by having.

According to the fifth aspect of the invention, as long as the inter-vehicle distance to the preceding vehicle does not fall below the approaching limit distance of the preceding vehicle, 1/2 of the sum of the detected value of the inter-vehicle distance in front and the detected value of the inter-vehicle distance in the rear is used. Is set as the inter-vehicle distance target value, and the vehicle speed is controlled based on the inter-vehicle distance target value.In other words, the inter-vehicle control is performed so that the own vehicle is located at the center between the preceding vehicle and the following vehicle. This makes it possible to control the own vehicle to an optimal position between the preceding vehicle and the following vehicle.

A vehicle running control device according to a sixth aspect of the present invention includes a vehicle speed detecting means for detecting a speed of the vehicle, and a vehicle distance target value for calculating a vehicle distance target value between the preceding vehicle and the vehicle. Calculating means, limit distance calculating means for calculating a preceding vehicle approach limit distance between the preceding vehicle and the own vehicle and a following vehicle approach limit distance between the following vehicle, and a limit distance calculating means for calculating the distance between the preceding vehicle and the own vehicle. The inter-vehicle distance detecting means for detecting the inter-vehicle distance in front and the inter-vehicle distance between the following vehicle and the own vehicle, and the inter-vehicle distance detection value detected by the inter-vehicle distance detecting means are calculated by the inter-vehicle distance target value calculating means. Vehicle speed control means for controlling the speed of the own vehicle based on the own vehicle speed detected by the own vehicle speed detection means so as to be equal to or more than the inter-vehicle distance target value, and the vehicle speed control means is detected by the inter-vehicle distance detection means. Rear inter-vehicle distance inspection When the value is less than the following vehicle approach limit distance, the vehicle is provided with an approach limit correction means for correcting the inter-vehicle distance target value to a small value within a range in which the preceding inter-vehicle distance detection value does not fall below the preceding vehicle approach limit distance. I have.

In the invention according to claim 6, the speed control of the own vehicle is performed so that the inter-vehicle distance between the preceding vehicle and the own vehicle is equal to or more than the inter-vehicle distance target value. At this time, when the inter-vehicle distance between the host vehicle and the following vehicle is less than a following vehicle approach limit distance that can ensure safety without, for example, causing the following vehicle to collide with the host vehicle when approaching further. In a range where the inter-vehicle distance between the preceding vehicle and the own vehicle does not fall below the preceding vehicle approach limit distance which can ensure safety without, for example, causing the own vehicle to collide with the preceding vehicle when approaching further. The target inter-vehicle distance is corrected to be small, and the vehicle speed control is performed so that the distance to the preceding vehicle is equal to or greater than the corrected target inter-vehicle distance.

Therefore, the vehicle speed is controlled so as to secure the distance to the following vehicle while maintaining at least the preceding vehicle approaching limit distance to the preceding vehicle, so that the distance to the preceding vehicle is reduced. The vehicle speed can be controlled to deal with the approach of the following vehicle in the secured state, avoiding a situation where there is a distance to the following vehicle but not to the preceding vehicle. It is also possible to reduce the distance between the vehicle and the preceding vehicle when the following vehicle approaches the vehicle below the approaching limit distance. As a result, it is possible to reduce the distance to the preceding vehicle at an accurate time without giving the driver a sense of incongruity.

Further, in the vehicle traveling control device according to the present invention, the approach limit correction means calculates a half of a sum of the front inter-vehicle distance detection value and the rear inter-vehicle distance detection value as the inter-vehicle distance target value. It is characterized by being set as. In the invention according to claim 7, the approach limit correction means includes a front inter-vehicle distance detection value and a rear inter-vehicle distance detection within a range in which the inter-vehicle distance between the preceding vehicle and the host vehicle does not fall below the preceding vehicle approach limit distance. Is set as the inter-vehicle distance target value, and the vehicle speed is controlled based on this value. That is, the own vehicle is positioned at the center between the preceding vehicle and the following vehicle. The vehicle-to-vehicle control is thus performed, so that the own vehicle can be controlled to an optimal position between the preceding vehicle and the following vehicle.

Further, the vehicle traveling control device according to claim 8 is provided with a warning means for issuing a warning to a following vehicle when the following inter-vehicle distance detection value falls below a warning generation threshold value. . In the invention according to the eighth aspect, when the inter-vehicle distance to the following vehicle is smaller than a warning generation threshold value such as a target value for a following inter-vehicle distance or a following vehicle approach limit distance, a warning is issued to the following vehicle. With this configuration, it is possible to recognize that the vehicle is too close to the following vehicle.

According to a ninth aspect of the present invention, the vehicle speed control means controls the rear inter-vehicle distance to be lower than a rear acceleration control threshold value and the front inter-vehicle distance to be forward acceleration controlled. When the threshold value is exceeded, the vehicle speed control is performed at a larger acceleration than when the condition is not satisfied. Further, the vehicle traveling control device according to claim 10 is characterized in that the vehicle speed control means performs vehicle speed control with a larger acceleration as the detected value of the distance between the rear vehicles is smaller.

According to the ninth or tenth aspect of the present invention, the inter-vehicle distance to the following vehicle is lower than a rear acceleration control threshold value, such as a target rear-vehicle distance or a following vehicle approach limit distance, and The distance between the cars
For example, when the vehicle speed exceeds a forward acceleration control threshold value such as an inter-vehicle distance target value or a preceding vehicle approach limit distance, that is, when the following vehicle is approaching, but there is a sufficient inter-vehicle distance with the preceding vehicle, Since the vehicle speed control is performed at an acceleration higher than usual, for example, when the preceding vehicle disappears from a state where the preceding vehicle and the following vehicle are approaching the own vehicle, the vehicle speed is controlled at an acceleration larger than normal. Since the control is performed and the acceleration is quickly performed, the inter-vehicle distance to the following vehicle can be quickly secured.

In particular, in the invention according to claim 10, the vehicle speed control is performed with a larger acceleration as the inter-vehicle distance to the following vehicle is shorter. Therefore, the acceleration is performed more rapidly as the following vehicle approaches. As a result, the inter-vehicle distance with the following vehicle is more quickly secured.

[0026]

According to the vehicle traveling control apparatus of the first aspect of the present invention, when the inter-vehicle distance between the host vehicle and the following vehicle is smaller than the rear inter-vehicle distance threshold value, the preceding vehicle and the host vehicle are connected to each other. The vehicle-to-vehicle distance between the host vehicle and the preceding vehicle is reduced as long as the vehicle-to-vehicle distance between the vehicles does not fall below the threshold for the preceding vehicle. The vehicle speed control can be performed so as to cope with the approach of the vehicle, and it is possible to avoid a situation in which there is a distance to the following vehicle but not to the preceding vehicle.

According to the second aspect of the invention, when the inter-vehicle distance between the host vehicle and the following vehicle is smaller than the target rear inter-vehicle distance, the inter-vehicle distance between the preceding vehicle and the host vehicle is reduced. As long as the distance does not fall below the inter-vehicle distance target value, the inter-vehicle distance target value is corrected to a small value and vehicle speed control is performed based on the corrected inter-vehicle distance target value. Can control the vehicle speed with respect to the approach of the following vehicle, and can avoid a situation in which there is a distance to the following vehicle but not to the preceding vehicle, and Since the distance between the following vehicle and the preceding vehicle is reduced when the following vehicle falls below the rear inter-vehicle distance target value, it is possible to deal with the approach of the following vehicle from an early stage.

According to the third aspect of the invention, the inter-vehicle distance between the preceding vehicle and the own vehicle is larger than the inter-vehicle distance target value, and the inter-vehicle distance between the following vehicle and the own vehicle is different. When the distance is smaller than the rear inter-vehicle distance target value,
Since the inter-vehicle distance target value is corrected so that the rear inter-vehicle distance detection value becomes the rear inter-vehicle distance target value, the inter-vehicle distance target value can be secured for each of the preceding vehicle, the following vehicle, and the host vehicle. The position of the own vehicle can be controlled at an appropriate position between the preceding vehicle and the following vehicle.

According to the vehicle travel control device of the fourth aspect, the target distance between the preceding vehicle and the host vehicle is corrected within a range that does not fall below the target distance between the preceding vehicle. , And the maximum inter-vehicle distance to the following vehicle can be ensured even if it is not the rear inter-vehicle distance target value. According to the vehicle travel control device of the fifth aspect, the sum of the front inter-vehicle distance detection value and the rear inter-vehicle distance detection value is set within a range in which the inter-vehicle distance to the preceding vehicle does not fall below the preceding vehicle approach limit distance. Is set as the inter-vehicle distance target value, it is possible to control the own vehicle so as to be positioned at the center between the preceding vehicle and the following vehicle, and to control the distance between the preceding vehicle and the following vehicle. The position of the own vehicle can be controlled at an appropriate position.

According to the vehicle traveling control device of the present invention, when the inter-vehicle distance between the host vehicle and the following vehicle is smaller than the following vehicle approach limit distance, the inter-vehicle distance between the preceding vehicle and the host vehicle is reduced. The target inter-vehicle distance is corrected to a small value within the range where the distance does not fall below the preceding vehicle approach limit distance, and vehicle speed control is performed based on this.Therefore, approaching the following vehicle with the distance to the preceding vehicle secured Vehicle speed control can be performed so as to deal with the following vehicle, and it is possible to avoid a situation in which there is a distance to the following vehicle but not to the preceding vehicle. Since the distance to the preceding vehicle is reduced when the vehicle approaches below the following vehicle approach limit distance, the distance to the preceding vehicle can be determined at an accurate time without giving the driver a sense of incongruity. Can be reduced .

Further, according to the vehicle traveling control device of the present invention, the inter-vehicle distance between the preceding vehicle and the host vehicle does not fall below the approaching limit distance of the preceding vehicle, and the detected value of the inter-vehicle distance between the front vehicle and the rear vehicle is determined. Since １ ／ of the sum of the detected inter-vehicle distance and the inter-vehicle distance target value is set as the inter-vehicle distance target value, the position of the own vehicle can be controlled at an appropriate position between the preceding vehicle and the following vehicle.

According to the vehicle traveling control device of the eighth aspect, when the inter-vehicle distance to the following vehicle is smaller than the warning generation threshold value, a warning is issued to the following vehicle. It can be recognized that the following vehicle is approaching too much. Further, according to the vehicle travel control device according to the ninth and tenth aspects, the detected value between the rear inter-vehicle distances is lower than the threshold value of the rear acceleration control and the detected value of the inter-vehicle distance ahead is higher than the threshold value of the front acceleration control. In some cases, the vehicle speed control is performed at a larger acceleration than when this condition is not satisfied. For example, when the host vehicle disappears from a state in which the host vehicle is approaching the preceding vehicle and the following vehicle, prompt control is performed. The vehicle is accelerated to quickly secure the inter-vehicle distance with the following vehicle.

In particular, in the invention according to claim 10, since the vehicle speed control is performed with a larger acceleration as the inter-vehicle distance to the following vehicle is shorter, the acceleration is performed more rapidly as the following vehicle approaches. As a result, the inter-vehicle distance with the following vehicle can be more quickly secured.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment when the present invention is applied to a rear-wheel drive vehicle.
In the figure, 1FL and 1FR denote left and right front wheels as driven wheels,
RL and 1RR are rear wheels as driving wheels, and are rear wheels 1R.
L and 1RR are driven to rotate by the driving force of the engine 2 being transmitted through the automatic transmission 3, the propeller shaft 4, the final reduction gear 5, and the axle 6.

Front wheels 1FL, 1FR and rear wheels 1RL, 1R
R has a disc brake 7 for generating a braking force.
The braking oil pressure of these disc brakes 7 is controlled by a braking control device 8. This braking control device 8
Is configured to generate a braking oil pressure according to the depression of the brake pedal 8a and to generate a braking oil pressure according to the target braking pressure P _B ^* from the follow-up control controller 20.

The engine 2 is provided with an engine output control device 9 for controlling the output. The engine output control device 9 includes, for example, a method of controlling the engine speed by adjusting the opening TH of the throttle valve and a method of controlling the engine speed by adjusting the opening TH of the idle control valve as the method of controlling the engine output. And a method of controlling the idle speed of the engine 2 by adjusting the opening of the idle control valve. In this embodiment, a method of adjusting the opening of the throttle valve 11 is employed. Have been.

The automatic transmission 3 is provided with a transmission control device 10 for controlling the shift position. on the other hand,
The lower body of the front side of the vehicle, the front vehicle distance sensor 12F is provided to detect an inter-vehicle distance L _F between the preceding vehicle, similarly, the underbody of the rear side of the vehicle, between the following vehicle Rear inter-vehicle distance sensor 12 for detecting the inter-vehicle distance L _R of the vehicle
R is provided. The front and rear inter-vehicle distance sensors 12F and 12R are configured by, for example, a laser system that sweeps a laser beam and receives reflected light from a preceding vehicle or a following vehicle. vehicle distance L _F between the vehicle and the vehicle, so as to measure L _R. The front and rear inter-vehicle distance sensors 12F and 12R are set to be able to capture the preceding vehicle ahead and the following vehicle behind, respectively.

The front and rear inter-vehicle distance sensor 1
As the 2F and 12R, for example, a laser device or the like that performs measurement using millimeter waves or ultrasonic waves can be applied. Further, the vehicle is provided with a vehicle speed sensor 13 that detects the own vehicle speed Vs by detecting the rotation speed of the propeller shaft 4. Further, a set switch 14 for selecting whether or not to perform the follow-up control, and a vehicle speed setting device 15 for setting a desired vehicle speed in the follow-up control are provided.

Then, the inter-vehicle distance sensors 12F, 12R,
Each detection signal of the vehicle speed sensor 13, a switch signal of the set switch 14 for selecting whether or not to perform the following control, and a vehicle speed setting signal of the vehicle speed setting device 15 are input to the following control controller 20. The follow-up control controller 20 includes detection signals and switch signals from various sensors, a throttle opening sensor 16 for detecting the opening of the throttle valve 11, an engine speed sensor 17 for detecting the engine speed, a torque converter. By controlling the braking control device 8, the engine output control device 9, and the transmission control device 10 based on detection signals from various sensors such as a torque converter output rotation speed sensor 18 for detecting the output rotation speed of the vehicle, A follow-up running control for performing a follow-up run while maintaining an appropriate inter-vehicle distance between the vehicle and the following vehicle is performed.

The tracking control controller 20 includes, for example, a microcomputer and peripheral devices such as a storage device. Then, as shown in the block diagram of FIG. 2, a detection signal of the vehicle speed sensor 13 is input to a signal input processing unit 21, and the signal input processing unit 21 converts a detection signal of the own vehicle speed Vs composed of a pulse signal into a digital signal. . The front and rear inter-vehicle distance sensors 12F, 1
Front-to-vehicle distance L _F and rear-to-vehicle distance L _R detected by 2R
Is input to the signal input processing unit 22 and converted into a digital signal here. Further, the set vehicle speed set by the vehicle speed setting device 15 is converted into a digital signal by the signal input processing unit 23. The signals processed by the signal input processing units 21 and 22 are input to the optimum inter-vehicle distance calculation unit 24.

In the target inter-vehicle distance calculating section 24, each signal
The own vehicle speed Vs from the input processing units 21 and 22 and the distance between the front vehicles
L_FAnd rear distance L_RAnd, based on
Target forward inter-vehicle distance (inter-vehicle distance target value) L_F ^*, And
This is output to the following distance control unit 25. The inter-vehicle control unit 25 includes:
Target inter-vehicle distance L calculated by target inter-vehicle distance calculation unit 24
_F ^*And the set vehicle speed V input by the signal input processing unit 23_C
And the set vehicle speed V_CUp to a certain distance
Target vehicle speed V for performing follow-up running while holding^*Calculate
This is output to the vehicle speed control unit 26.

In the vehicle speed control unit 26, the distance control unit 25
Target vehicle speed V^*Acceleration / deceleration G based on the actual vehicle speed Vs
^*And outputs it to the target braking / driving torque calculation unit 27.
I do. In the target braking / driving torque calculation unit 27, the vehicle speed control
Target acceleration / deceleration G from section 26 ^*Drive shaft torque based on
And calculates this as the braking fluid pressure calculation unit 28 and the engine output performance.
Output to the calculation unit 30.

The braking hydraulic pressure calculating section 28 calculates a target braking pressure P _B ^* based on the drive shaft torque calculated by the target braking / driving torque calculating section 27, and uses this as a braking pressure command value. And outputs the result to the braking control device 8 via. Further, the engine output calculation unit 30 calculates a target throttle opening θ ^* based on the drive shaft torque calculated by the target braking / driving torque calculation unit 27, and uses this as a throttle opening command value via the signal output processing unit 31. And outputs it to the engine output control device 9.

Next, the operation of the first embodiment will be described with reference to the flowchart of FIG. 3 showing the processing procedure of the follow-up traveling control process executed by the follow-up control controller 20. The follow-up control controller 20 executes the follow-up traveling control process shown in FIG. 3 as a timer interrupt process, for example, every 10 msec. In the following traveling control process, first, in step S1, the following distance sensors 12F, 12R,
Each detection signal of the vehicle speed sensor 13 and the set switch 1
4 to read the own vehicle speed Vs, the distance L _F between the front vehicle and the distance L _R between the rear vehicle.

Next, the process proceeds to step S2, where it is determined whether or not the set switch 14 is turned on, that is, whether or not a follow-up traveling instruction has been issued. Then, step S2
When the follow-up traveling instruction has been issued, step S
The process proceeds to 3 to determine whether a preceding vehicle has been detected. This determination may, for example carried by the front inter-vehicle distance L _F read in step S1 to determine whether it is within the detection limit of the forward vehicle distance sensor 12F, when the front inter-vehicle distance L _F is within the detection limits It is determined that there is a preceding vehicle, and the process proceeds to step S4. On the other hand, it is judged that there is no preceding vehicle when the front inter-vehicle distance L _F is larger than the detection limit value, the process proceeds to step S20 described later.

In step S4, it is determined whether a following vehicle has been detected. This determination is made, for example, in step S1.
Read in the rear inter-vehicle distance L _R is the rear inter-vehicle distance sensor 1
The determination is made as to whether or not the distance is within the detection limit of 2R. When the rear inter-vehicle distance _LR is within the detection limit, it is determined that there is a following vehicle, and the process proceeds to step S5. On the other hand, when the rear inter-vehicle distance L _R is greater than the detection limit also in determining that there is no following vehicle, the process proceeds to step S15 described later.

In the step S5, the rear inter-vehicle distance L _R
Is determined to be less than the limit rear vehicle distance (the following vehicle approach limit distance) L _R-LIM (L _R <
_LR-LIM ). The limit rear distance L _R-LIM is a value set by the following equation (1). Note that V _R in the formula speed of the following vehicle, g is the maximum acceleration that can be generated in the vehicle, L
_R 'is a first-order differential value of the rear inter-vehicle distance L _R.

L_R-LIM= (Vs^Two-V_R ^Two) / 2g (1) V_R= L_R'+ Vs and L_R<L_R-LIMIf it is, go to step S6.
Transition, L_R<L_{R-LI M}If not, step S15
Move to In step S6, the inter-vehicle distance L ahead_F
Is the limit distance between vehicles ahead (limit distance to approach the preceding vehicle) L_F-LIMTo
It is determined whether or not it exceeds (L_F> L_F-LIM).
The limit forward inter-vehicle distance L_F-LIMIs set by the following equation (2).
Value. Note that V in the equation_FIs the speed of the preceding vehicle, g
Is the maximum acceleration / deceleration that can be generated by the vehicle, L_F′ Is the distance between vehicles ahead
Distance L_FIs the first derivative of

L_F-LIM= (V_F ^Two-Vs^Two) / 2g ... (2) V_F= L_F'+ Vs and L_F> L_F-LIMIf step S10
To L_F> L_{F- LIM}If not, step S
Move to 15. In the step S10, the vehicle
Target inter-vehicle distance L which is the target value of the inter-vehicle distance between_F ^*
Is set according to the following equation (3). And step
The process moves to S17.

[0050] ^{_{L F * = (L F +}} L R) / 2 ...... (3) On the other hand, in step S15, the target front inter-vehicle distance L _F
^* Is calculated according to the following equation (4). Then, control goes to a step S17. Incidentally, in the formula, T ₀ is the time (headway time constant value) to reach the position of the rear L ₀ of the preceding vehicle the vehicle is currently (m), Vs is the host vehicle speed, L _F is the front vehicle The inter-vehicle distance _LST is the inter-vehicle distance when stopped.

L _F ^* = T ₀ × (Vs + dL _F / dt) + L _ST (4) In step S17, as shown in FIG. 4, the target inter-vehicle distance L _F ^* calculated in step S10 or S15 is calculated. Based on a reference model set in advance for filtering the feedforward phase compensator G _FF (s), the feedback compensator G _FB (s), and the target front inter-vehicle distance L _F ^* to suppress a sudden change. Calculate V ^* .

That is, the target front inter-vehicle distance L _F ^* is passed through a feedforward phase compensator G _FF (s) represented by a transfer function including, for example, a second-order secondary phase advance element. Calculate the value VSP _FF . Further, from the target front inter-vehicle distance L _F ^* vehicle distance and relative speed obtained through reference model, the actual inter-vehicle distance L _F and the actual relative vehicle speed [Delta] V (dL _F obtained by differentiating the inter-vehicle distance L _F
/ Dt), and a feedback compensation value VSP _FB obtained by passing this through a feedback compensator G _FB (s) represented by, for example, a first-order transfer function. The phase compensation value VSP _FF and the feedback compensation value VSP
_FB is added, and this added value is subtracted from the added value of the actual relative vehicle speed ΔV and the own vehicle speed Vs, and this is set as the target vehicle speed V ^* .

The transfer function G _FF (s) of the feedforward phase compensator is, for example, the inter-vehicle distance control response characteristic ω ² /
(S ² + 2ζωs + ω ² ) and the following distance L from the vehicle speed
It is expressed as the product of the transfer function up to _F and the inverse system. Further, a transfer function from the vehicle speed to the distance L _F between the front vehicle is expressed by a product of a transfer characteristic ω _V / (s + ω _V ) of a vehicle speed control system and an integrator for integrating a relative speed to obtain an actual vehicle speed. Ω
_V / [s (s + ω _V )]. Therefore, the transfer function G _FF (s) of the feedforward phase compensator is represented by the following equation (5).

G _FF (s) = ω ² · s (s + ω _V ) / {ω _V (s ² + 2ζωs + ω ² )} (5) Further, the transfer function G _FB (s) of the feedback compensator
Is represented by the following equation (6). Incidentally, f _V in the formula is a gain related to the velocity components, is f _d is a gain related to the distance component.

G_FB(S) = f_V・ S + f_d (6) Next, the process proceeds to step S18, where the calculation is performed in step S17.
Target vehicle speed V^*Target acceleration / deceleration by differentiating
G^*(G^*= DV^*/ Dt) is calculated. Next,
The process proceeds to step S19, where the target calculation calculated in step S18 is performed.
Deceleration G ^*The distance between vehicles is controlled based on.

That is, the target wheel torque τ _W ^* is calculated based on the target acceleration / deceleration G ^* , the vehicle weight m and the wheel radius r. Then, based on the engine rotation speed N _E (rpm) detected by the engine rotation speed sensor 17 and the torque converter output rotation speed _NT (rpm) detected by the torque converter output rotation speed sensor 18, the following equation (7) is calculated. Then, the speed ratio e is calculated.

E = N _T / N _E (7) Next, based on the speed ratio e, a torque ratio η _T is calculated by referring to a torque ratio calculation map stored in advance in a storage device such as a ROM. . For example, as shown in FIG. 5, the torque ratio calculation map takes the maximum torque ratio when the speed ratio e is “0”, and the torque ratio η _T changes linearly as the speed ratio e increases from this state. It is set so that it may decrease.

Then, based on the target wheel torque τ _W ^* , the torque ratio η _T , and the gear ratio η _G , the following equation (8) is calculated to calculate the target engine torque τ _E ^* . [tau] _E ^* = [tau] _W ^* / ([eta] _T ^{* [} eta] _G ) (8) Next, based on the calculated target engine torque [tau] _E ^* and the engine speed _NE, it is stored in advance in a storage device such as a ROM. The target throttle opening θ ^* is calculated with reference to the current throttle opening calculation map. The throttle opening calculation map set, for example, as shown in FIG. 8, taking the engine rotational speed N _E to the horizontal axis, the vertical axis target engine torque tau _E ^* the taking, the target throttle opening theta ^* as a parameter are, the target throttle opening theta ^* is substantially linearly decreases according to the increase of the engine rotational speed N _E when is about 40%, the target throttle opening theta ^* 60% 100
%, The curvature is set to be convex so that the curvature increases as the increase increases. Conversely, when the target throttle opening θ ^* decreases to 20 to 0%, the curvature increases as the decrease increases. The ratio is set to be concave to increase. Then, the target throttle opening theta ^* is 20% or less when the engine speed N _E to generate an engine braking force becomes the target engine torque tau _E ^* becomes negative when increased.

Next, the actual throttle opening θ, engine
Rotation speed N_E, Target acceleration / deceleration G^*Target system based on
Dynamic pressure P_B ^*Is calculated and output to the braking control device 8
Terminates the timer interrupt processing from the
Return to Ram. The target braking pressure P_B ^*First, the slot
Actual throttle opening detected by the throttle opening sensor 16
θ and the engine speed detected by the engine speed sensor 17.
Rolling speed N _EFrom the above, the throttle opening calculation method shown in FIG.
Engine torque τ_EIs calculated.

Then, the calculated engine torque τ_EPassing
And the aforementioned torque ratio τ_TAnd gear ratio η _GBased on
By performing the calculation of (9), the estimated wheel torque value τ_W
Is calculated. τ_W= Τ_E・ Η_T・ Η_G (9) Next, the estimated wheel torque value τ_W, Vehicle weight m and wheel half
By calculating the following equation (10) based on the diameter r,
The deceleration estimated value G is calculated.

G = τ _W / (r · m) (10) Next, the following equation (11) is calculated based on the target acceleration / deceleration G ^* calculated in step S 18 and the acceleration / deceleration estimated value G. The acceleration / deceleration deviation ΔG is calculated. ΔG = G ^* −G (11) Then, wheel radius r, vehicle weight m, and acceleration / deceleration deviation ΔG
The target braking torque τ _B ^* is calculated by performing the calculation of the following equation (12) based on

Τ _B ^* = r · m · ΔG / 2 (12) Based on the target braking torque τ _B ^* and the control gain g _C , the following equation (13) is used to calculate the target braking pressure P _B Calculate ^* . ^{_{P B * = -g C · τ}} B * ...... (13) and outputs a target throttle opening theta ^* to the engine output control unit 9, also outputs the target braking pressure P _B ^* to the braking controller 8 .

In response to this, in the engine output control device 9, the throttle opening deviation between the target throttle opening θ ^* input from the follow-up control controller 20 and the actual throttle opening θ detected by the throttle opening sensor 16. Δθ is calculated and, for example, P
Performs the ID control, etc., it calculates a throttle actuator command value theta _T, controls the throttle opening theta and outputs it to the throttle valve 11.

Further, the braking control device 10 calculates a braking pressure deviation ΔB between the target braking pressure P _B ^* input from the following control controller 20 and the actual braking pressure P _B, and calculates the braking pressure deviation ΔP _B based braking pressure command value P _BT is calculated by performing with eg a PID control, and supplies the braking pressure P in accordance with the braking pressure command value P _BT to the disc brakes 7. On the other hand, in step S20, since it is determined that there is no preceding vehicle, a vehicle speed control process is performed in which the set vehicle speed set by the driver with the vehicle speed setting device 15 is set as the target vehicle speed V ^*, and the target vehicle speed Vs is made to coincide with the target vehicle speed Vs. After that, the timer interrupt processing ends and the program returns to the predetermined main program.

That is, first, the target acceleration / deceleration G _V ^* is calculated so that the actual vehicle speed Vs matches the target vehicle speed V ^* set by the driver. The target acceleration / deceleration G _V ^* is obtained by subtracting the own vehicle speed Vs from the target vehicle speed V ^* and the vehicle speed deviation ΔVs (=
V ^* -Vs), and based on the vehicle speed deviation ΔVs, for example, by performing PID control. And
Based on the target acceleration / deceleration G _V ^* , the above (7), (8)
While calculating the equation, the torque ratio η _T is calculated with reference to the torque ratio calculation map of FIG. 5, and further, the target throttle opening θ ^* is calculated with reference to the throttle opening calculation map of FIG. This is output to the engine output control device 10 and then the timer interrupt process is terminated to return to a predetermined main program.

Therefore, when the vehicle is in the following control state with the driver setting the target vehicle speed V ^* and the preceding vehicle and the following vehicle are not being captured by the inter-vehicle distance sensors 12F and 12R, FIG. through steps S2 S3 in the follow-up running control process proceeds to step S20, the set vehicle speed set by the driver in advance and the target vehicle speed V ^*, based on the vehicle speed deviation ΔV between the target vehicle speed V ^* and the current vehicle speed Vs calculating a vehicle speed control target acceleration G _V ^* Te, the target throttle opening degree θ on the basis of the vehicle speed control target acceleration G _V ^*
By calculating ^* and outputting it to the engine output control device 9, the own vehicle speed Vs matches the preset target vehicle speed V ^* only by controlling the throttle opening without exerting the braking force with the disc brake 7. Vehicle speed control is performed.

When the preceding vehicle is captured by the inter-vehicle distance sensor 12F from this vehicle speed control state, the process moves from step S3 to S15 via S4, and the own vehicle moves to the current position L ₀ [m] behind the preceding vehicle. time preset to reach the position T ₀ (the inter-vehicle time), the vehicle speed Vs based on the detection signal of the vehicle speed sensor 13, based on said forward inter-vehicle distance L _F from the front inter-vehicle distance sensor 12 (4) to calculate the target front inter-vehicle distance L _F ^* in accordance with.

Then, based on the target inter-vehicle distance L _F ^* calculated in step S15, a phase compensation value VSP _FF is calculated from the above equation (5), and a feedback compensation value VSP _FB is calculated from the above equation (6). Is calculated. Then, these added values, and subtracted from the sum of the relative vehicle speed [Delta] V _F and vehicle speed Vs obtained by differentiating the front inter-vehicle distance L _F, the target vehicle speed V
Calculate ^* .

The position complement calculated in this way is
Reward VSP_FFTarget vehicle speed V based on ^*Calculate this eye
Marking vehicle speed V^*Acceleration / deceleration G based on^*Is calculated (step
Step S18), the target acceleration / deceleration G^*Goals that can achieve
Throttle opening θ^*, Target braking pressure P_B ^*Is calculated (step
Step S19), these are respectively connected to the engine output control device.
9. Output to the braking control device 8.

In response to this, the engine output control device 9 or the brake control device 8 is operated, and the throttle valve 11
Is controlled and the driving force or the braking force is generated to generate the target acceleration / deceleration G ^*. The vehicle travels at the target vehicle speed V ^* while maintaining an appropriate inter-vehicle distance.

From this state, the front inter-vehicle distance sensor 12F
At the same time, the following vehicle is also detected by the rear inter-vehicle distance sensor 12R.
When the supplementary state is reached, steps S4 to S5
Move to And the rear inter-vehicle distance L_RBut the above (1)
Limit rear distance L set by the formula _R-LIMSmaller than
The vehicle is not too close to the following vehicle.
When the vehicle is not
Move from step S5 to step S15 as all
Vehicle so that the distance from the preceding vehicle remains constant.
Processing is performed based on the speed Vs.

[0072] From this state, been following vehicle is catching up, when the host vehicle approaches the rear inter-vehicle distance L _R becomes smaller than the limit rearward vehicle distance L _R-LIM, and proceeds from step S5 to step S6, in turn forward determining whether the inter-vehicle distance L _F is greater than the limit front inter-vehicle distance L _F-LIM. Then, when the front inter-vehicle distance L _F is greater than the limit front inter-vehicle distance L _F-LIM, i.e., when not too close to the preceding vehicle, the process proceeds from step S6 to step S10, on the basis of the equation (3) Forward target inter-vehicle distance L _F
^* , The target vehicle speed V ^* is calculated based on the target inter-vehicle distance L _F ^* , and vehicle speed control is performed so as to reach the target vehicle speed V ^* . That is, the control is performed so that the own vehicle is located between the preceding vehicle and the following vehicle. Therefore, there is no situation in which the vehicle is relatively close to the preceding vehicle even though the own vehicle and the following vehicle are approaching.

From this state, for example, the preceding vehicle decelerates,
The distance between vehicles in front is shorter, and L_F> L _F-LIMNot satisfied
Then, the process proceeds from step S6 to step S15,
The target inter-vehicle distance L based on the vehicle speed_F ^*The set
The inter-vehicle control is performed based on this. Therefore,
This time, the vehicle was too close to the preceding vehicle, and this time it was the
L_F-LIMVehicle speed control will be performed to ensure
Thus, the risk of collision with the preceding vehicle is avoided.

Conversely, if the preceding vehicle accelerates and the preceding inter-vehicle distance sensor 12F cannot catch the preceding vehicle, the process shifts from step S3 to step S20, and the vehicle speed setting device is set in advance without considering the existence of the preceding vehicle. The vehicle speed control is performed so that the vehicle travels at the set vehicle speed set by the driver in 15. Further, the preceding vehicle and the following vehicle are connected to the inter-vehicle distance sensors 12F, 1F.
If the following vehicle cannot be captured from the state where the vehicle is being captured by the 2R, the process shifts from step S4 to step S15, and based on the vehicle speed of the own vehicle, the target inter-vehicle distance L is determined so as to keep the distance to the preceding vehicle constant. _F ^* is set, and the headway control is performed based on this.

[0075] Thus, when the following vehicle is too close to the vehicle, if there is some distance between the preceding vehicle, the sum of the front inter-vehicle distance L _F and the rear inter-vehicle distance L _R 1
/ 2 is set as the target inter-vehicle distance L _F ^* , and the own vehicle speed V
s-based inter-vehicle distance control, the distance between the preceding vehicle and the preceding vehicle is reduced, and the distance between the preceding vehicle and the following vehicle is ensured. In consideration of the above, the inter-vehicle distance control is performed, so that it is possible to avoid a situation in which the distance to the following vehicle is sufficient even though the distance to the following vehicle is narrow. It is possible to avoid giving the driver an uncomfortable feeling.

Further, as shown in FIG.
When the preceding vehicle is B and the succeeding vehicle is C,
The inter-vehicle distance between the following vehicle C and the own vehicle A is the limit rear inter-vehicle distance L.
_{R-LI M}When the vehicle falls below the vehicle, the preceding vehicle B and the vehicle A
The inter-vehicle distance is the distance L _F-LIMNot less than
To adjust the distance between the vehicles ahead and connect the vehicle A to the vehicle B ahead.
The distance between the vehicle and the preceding vehicle B
Even if it is packed, safety can be ensured.

At this time, only when the inter-vehicle distance between the vehicle and the following vehicle falls below the limit rear inter-vehicle distance L _R-LIM ,
Since the inter-vehicle distance with the preceding vehicle is reduced, the vehicle does not approach the preceding vehicle in a state where the inter-vehicle distance with the following vehicle is sufficiently large, and does not give the driver an uncomfortable feeling. In addition, the sum of the front inter-vehicle distance L _F and the rear inter-vehicle distance L _R is 1 /.
2 is set as the target front inter-vehicle distance L _F ^* , so that in an limited range between the preceding vehicle and the following vehicle, the optimum position is set so that neither the preceding vehicle nor the following vehicle is too close. The vehicle can be positioned.

The vehicle speed sensor 13 corresponds to the own vehicle speed detecting means, and the front inter-vehicle distance sensor 12F and the rear inter-vehicle distance sensor 12R correspond to the inter-vehicle distance detecting means. In steps S5 and S6 of FIG. Distance L
_The processing of calculating the _R-LIM and the limit front inter-vehicle distance _LF-LIM corresponds to the limit distance calculation means, the processing of step S10 corresponds to the approach limit correction means, and the processing of step S15 is the inter-vehicle distance target value calculation means. The processing of steps S17 to S19 and step S20 corresponds to the vehicle speed control means, the limit rear inter-vehicle distance _LR-LIM corresponds to the rear inter-vehicle distance threshold, and the limit front inter-vehicle distance _LF-LIM It corresponds to the threshold value for the distance between vehicles ahead.

Next, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment in that when the own vehicle is too close to the preceding vehicle,
Since a warning is issued to a following vehicle, and the processing is the same except that a part of the processing procedure in the follow-up control processing is different, the same reference numerals are given to the same parts, and the detailed description thereof will be omitted. .

In the second embodiment, FIG.
The flowchart shows the processing procedure of the tracking control processing.
As described above, the tracking control process in the first embodiment shown in FIG.
In the process, the process of step S6a is added.
That is, in the process of step S6, the front inter-vehicle distance L_FBut
Limit front inter-vehicle distance L_{F- LIM}When smaller than
The process proceeds to step S6a, and a warning process is performed for the following vehicle.
After that, the process proceeds to step S15.

In the alerting process, for example, a hazard lamp is turned on, a brake lamp is turned on, or high-intensity lighting or blinking is performed, and a fog lamp on the rear is turned on or blinking. Therefore, the driver of the following vehicle can recognize that the preceding vehicle of the following vehicle is too close to the preceding vehicle by blinking these lamps and the like. Such measures can be taken. Therefore, the safety of the own vehicle can be further secured.

It should be noted that the processing in step S6a in FIG.
Corresponding to the means, the distance L _F-LIMHas a warning
It corresponds to the threshold. Next, a third embodiment of the present invention
Explain the situation. The third embodiment is similar to the first embodiment.
In the embodiment, one of the processing procedures in the tracking control processing is described.
It is the same except that the part is different, so the same part is the same
Reference numerals are given, and the detailed description is omitted.

In the third embodiment, follow-up control processing is performed according to the processing procedure shown in FIG. That is, first, in step S31, each detection signal of the following distance sensors 12F and 12R and the vehicle speed sensor 13,
It reads the switch signal of the set switch 14, and calculates vehicle speed Vs, the front inter-vehicle distance L _F, the rear inter-vehicle distance L _R.

Then, the flow shifts to step S32, where it is determined whether or not the set switch 14 is turned on, that is, whether or not a follow-up traveling instruction has been issued. If the follow-up traveling instruction has not been issued, the process is terminated. When the follow-up traveling instruction is given in step S32, the process proceeds to step S33, and it is determined whether or not the preceding vehicle has been captured in the same manner as in the first embodiment. The process then proceeds to calculate the target inter-vehicle distance L _F ^* according to the processing procedure shown in FIG. Then
The process proceeds to step S35, and based on the target front inter-vehicle distance L _F ^* calculated in step S34, after calculating the target vehicle speed V ^* in the same manner as the process of step S17 in FIG. 3 in the first embodiment, The process proceeds to step S36 to calculate a target acceleration / deceleration G ^* by differentiating the target vehicle speed V ^* calculated in step S35.

Then, the process shifts to step S37 to execute step S37 in the same manner as in step S19 in FIG.
The following distance control is performed based on the target acceleration / deceleration G ^* calculated in 36. On the other hand, when the preceding vehicle is not captured in step S33, the process proceeds to step S41, and the set vehicle speed previously set by the driver with the vehicle speed setting device 15 is set as the target vehicle speed V ^* .

Then, the process proceeds to a step S42, wherein the target vehicle
Speed V^*Is greater than the actual vehicle speed Vs
Then V^*If> Vs, proceed to step S43
And the rear inter-vehicle distance L_RIs the target rear inter-vehicle distance L described later._R ^*
It is determined whether it is smaller than. And L_R<L_R
^*Is satisfied, the process proceeds to step S44, and the first
Processing in Step S20 of FIG. 3 in Embodiment
The vehicle speed control is performed in the same manner as described above.
Target acceleration / deceleration calculated based on the set vehicle speed set in Step 5
Degree G^*And G^*= K_One・ G^*Update as and after this update
Target acceleration / deceleration G ^*Car speed control is performed so as to realize

K ₁ is a gain satisfying K ₁ > 1, and for example, as shown in FIG. 11, K ₁ > 1.
And the rear inter-vehicle distance L _R is set to a value closer to about "1" to increase. On the other hand, in step S42, V ^* > Vs
If not, or if L _R <L _R ^* in step S43, the process moves to step S45. This step S
In step 45, the vehicle speed control is performed in the same manner as in the processing in step S20 of FIG. 3 in the first embodiment, and the target acceleration / deceleration G ^* calculated based on the vehicle speed set by the vehicle speed setting device 15 is realized. Perform vehicle speed control.

The calculation of the target inter-vehicle distance in step S34 is performed according to the processing procedure shown in FIG. That is, first, in step S51, it is determined whether or not there is a following vehicle, and if there is no following vehicle, the process is terminated as it is. on the other hand,
If there is a following vehicle, the process proceeds to step S52, where the target front inter-vehicle distance L _F ^* and the target rear inter-vehicle distance are target values of the inter-vehicle distance between the preceding vehicle and the own vehicle, and between the following vehicle and the own vehicle. (Rear target distance between vehicles) _LR ^* is calculated. The target front inter-vehicle distance L _F ^* is, for example, the above (4)
Calculated based on the formula, when calculating the target rear inter-vehicle distance L _R ^* between the following vehicle is the L _F of the equation (4) L
Now referred to as _R, it is calculated on the basis of the backward inter-vehicle distance L _R.

Next, the processing shifts to step S53, where the rear vehicle
Distance L_RIs the target rear vehicle distance L_R ^*Is below
Is determined (L_R<L_R ^*), L_R<L_R ^*When not
Ends the processing as it is, and L_R<L_R ^*When
Move to step S54. In this step S54,
Forward distance L_FIs the target inter-vehicle distance L_F ^*More than
Is determined (L_F> L_F ^*). And L_F> L
_F ^*If not, the process proceeds to step S55.

In this step S55, the distance L
_F is determined whether the above limit forward inter-vehicle distance _{L F-LIM, L F>} L F-LIM is when a proceeds to step S56, wherein (3) the target front inter-vehicle distance based on the equation L _F ^*
Is calculated. Then, the process ends. On the other hand, if L _F > L _F-LIM is not _satisfied in step S55, step S5
Then, the process proceeds to step S7, and after performing an alerting process for alerting the following vehicle, such as blinking a hazard lamp, the process ends.

In step S54, L _F > L _F
^If it is ^* , the process moves to step S61, and the following expression (1)
It is determined whether 4) is satisfied. L _F + L _R > L _F ^* + L _R ^* (14) Then, when the expression (14) is satisfied, step S
The process proceeds to 62, and the post-processing is completed after calculating the target front inter-vehicle distance L _F ^* according to the following equation (15).

[0092] ^{_{L F * = L F + L}} R -L R * ...... (15) On the other hand, when not satisfying the equation (14), the process proceeds to step S56. Therefore, when the own vehicle is in the following control state and the preceding vehicle and the following vehicle are not captured by the inter-vehicle distance sensors 12F and 12R, the process shifts from step S33 to S41 in the following traveling control process of FIG. The target vehicle speed set by the user with the vehicle speed setting device 15 is set as the target vehicle speed V ^*, and the target acceleration / deceleration G _V for vehicle speed control is determined based on the vehicle speed deviation ΔV between the target vehicle speed V ^* and the current vehicle speed Vs.
^* , The target throttle opening θ ^* is calculated based on the target acceleration / deceleration G _V ^* for vehicle speed control, and the calculated throttle opening θ ^* is output to the engine output control device 9 so that the disc brake 7 exerts a braking force. Instead, the vehicle speed control is performed only by controlling the throttle opening so that the own vehicle speed Vs matches the preset target vehicle speed V ^* .

When the preceding vehicle is captured by the inter-vehicle distance sensor 12F from the vehicle speed control state, the process shifts from step S33 to S34 and shifts to step S51 in FIG. 10, but the following vehicle is not captured. Returning to FIG. 9, the process proceeds to step S35, where the target vehicle speed V ^* is calculated in the same manner as in the first embodiment based on the target inter-vehicle distance L _F ^* calculated based on the own vehicle speed Vs. The target acceleration / deceleration G ^* is calculated based on the target vehicle speed V ^* (step S36), and the following distance control is performed so as to realize the target acceleration / deceleration G ^* (step S37). by this,
The inter-vehicle control is performed such that the inter-vehicle distance between the own vehicle and the preceding vehicle secures the target inter-vehicle distance L _F ^* calculated based on the own vehicle speed Vs.

From this state, the front inter-vehicle distance sensor 12F
At the same time, when the rear inter-vehicle distance sensor 12R is also in a state of supplementing the following vehicle, the process proceeds from step S51 of FIG. 10 to step S52 via steps S33 and S34, and the target inter-vehicle distances L _F ^* and L _R ^* in the front and rear directions ^. Is calculated, and when the rear inter-vehicle distance L _R is not smaller than the target rear inter-vehicle distance L _R ^*, it is determined that the vehicle is safe without considering the following vehicle, and the process returns from FIG. 9 to step S53 and returns to steps S35 and S36. The flow shifts to S37, where the inter-vehicle control is continued so as to secure the target inter-vehicle distance L _F ^* calculated based on the own vehicle speed Vs.

From this state, the following vehicle catches up
And approaching the own vehicle and following the rear inter-vehicle distance L_RIs the target rear vehicle distance
Release L_R ^*If it becomes smaller, the process proceeds from step S53.
The process moves to step S54. Here, the host vehicle contacts the preceding vehicle.
When not near, L_F<L_F ^*Because it is
From step S54 to step S61.
Distance L_FAnd rear distance L_RIs the sum of the following distance
Target value L for separation and rear vehicle distance_F ^*, L _R ^*Than the sum of
When large, that is, between the preceding vehicle and the following vehicle,
If the position of the own vehicle is set properly,
In a positional relationship that can satisfy the target value of the distance between vehicles
If there is, move from step S61 to step S62.
Go to the target forward headway distance L_F ^*The distance between vehicles ahead
And the following distance L_F, L_ROf the distance between the vehicles from the sum of
Value L_R ^*Set a value obtained by subtracting.

Then, the target vehicle speed V ^* and the target acceleration / deceleration G ^* are calculated based on the target inter-vehicle distance L _F ^* thus set, and control is performed to realize the target acceleration / deceleration G ^* . Therefore, the own vehicle is controlled between the preceding vehicle and the following vehicle so that the rear inter-vehicle distance L _R satisfies the target value L _R ^* , and the rear inter-vehicle distance L _R becomes the target value L _R ^*. At this time, and at this time, the distance L
_Since the sum of _F and the rear inter-vehicle distance L _R is larger than the sum of the target values L _F ^* and L _R ^* of the front inter-vehicle distance and the rear inter-vehicle distance, the inter-vehicle distance to the preceding vehicle is also equal to the target value L _F. ^* Is satisfied, and the own vehicle is located at a position where the target value of the inter-vehicle distance is secured between each of the preceding vehicle and the following vehicle and the own vehicle.

Then, from this state, the inter-vehicle distance to the preceding vehicle is reduced, and the inter-vehicle distance L _F in front becomes the target inter-vehicle distance L _F ^*.
If it is smaller than the above, steps S54 to S5
Proceeds to 5, the front inter-vehicle distance L _F is a limit front inter-vehicle distance L
_While it is larger than _F-LIM , the process proceeds to step S56,
The target front inter-vehicle distance L _F ^* is set to の of the sum of the front inter-vehicle distance L _F and the rear inter-vehicle distance L _R , that is, such that the host vehicle is located at the center between the preceding vehicle and the following vehicle. Set. Thereby, control is performed such that the host vehicle is located at the center between the preceding vehicle and the following vehicle.

[0098] From this state, further, the vehicle approaches the preceding vehicle, the front inter-vehicle distance L _F is below the critical vehicle distance L _F-LIM, and proceeds from step S55 to S57, alerting for subsequent vehicle Is performed, control is performed so as to secure the target inter-vehicle distance L _F ^* calculated based on the own vehicle speed Vs in step S52. This allows the following vehicle to
It is possible to recognize that the preceding vehicle is further approaching the preceding vehicle, and may decelerate.

Then, from this state, the preceding vehicle accelerates.
Forward distance L_FIs the distance L ahead of the limit_F-LIMGreater than
When it is determined, the process proceeds from step S55 to step S56.
As described above, the host vehicle is located at the center between the preceding vehicle and the following vehicle.
Is controlled to be located at
The distance increases, and the distance L_F> Target forward distance L _F
^*Then, the process proceeds from step S54 to step S61.
The following distance between the vehicle and the following vehicle is the target rear following distance L_R
^*The vehicle speed is controlled so as to secure the vehicle speed.

When the distance from the preceding vehicle further increases and the preceding vehicle cannot be captured by the front vehicle speed sensor 12F, the process shifts from step S33 to step S41. At this time, the own vehicle speed Vs becomes the target vehicle speed V ^*, that is, When the vehicle speed is higher than the set vehicle speed and it is not necessary to accelerate, the process proceeds from step S42 to step S45, where the vehicle speed set by the vehicle speed setting device 15 is set as the target vehicle speed V ^*, and the vehicle speed is controlled based on the target vehicle speed V ^*. However, when it is necessary to accelerate the own vehicle speed Vs lower than the target vehicle speed V ^* , the process shifts from step S42 to step S43, and the vehicle speed setting device 1
The set vehicle speed set in 5 to the target vehicle speed V ^*, perform vehicle speed control based on this, this time, largely corrects the target combustible rate G is calculated based on the target vehicle speed V ^* by the gain K _1, The vehicle speed control is performed based on the corrected target acceleration / deceleration G ^* . That is, the vehicle speed control is performed at an acceleration higher than usual.

Therefore, since the target acceleration / deceleration G is corrected to a larger value than usual, it is possible to return the vehicle speed to the set vehicle speed more quickly than usual by controlling the vehicle speed based on the target acceleration / deceleration G. it can. Further, when the preceding vehicle disappears in a state where the following vehicle is approaching, the vehicle rapidly accelerates, so that a distance to the following vehicle can be quickly secured.

Therefore, also in this case, when the following vehicle approaches the own vehicle and there is a certain distance from the preceding vehicle, the distance between the preceding vehicle and the preceding vehicle is reduced. Although there is a short distance between the vehicle and the preceding vehicle, there is no situation in which there is a sufficient distance from the preceding vehicle, and the driver does not feel uncomfortable. Therefore, the same operation and effect as those of the first embodiment can be obtained.

At this time, even when the following vehicle is relatively close, the vehicle is relatively far away from the preceding vehicle, and the distance between the preceding vehicle and the following vehicle is larger than the distance between the preceding vehicle and the following vehicle. It is larger than the sum of the target inter-vehicle distances with the vehicle, and if the position of the own vehicle is properly adjusted, the respective target inter-vehicle distances L _F ^* and L _R ^* are set as the inter-vehicle distance with the preceding vehicle and the inter-vehicle distance with the following vehicle. When it can be ensured, the position of the own vehicle is adjusted so that the distance to the following vehicle satisfies the target rear vehicle distance L _R ^*. The distance L _R ^* can be ensured, and the approach of the host vehicle to the preceding vehicle can be minimized, and the discomfort given to the driver can be minimized.

Further, when it is impossible to catch the preceding vehicle while approaching the following vehicle, the vehicle speed control is performed at an acceleration higher than usual, so that the vehicle speed can be quickly returned to the set vehicle speed. Further, the distance to the following vehicle can be quickly secured. At this time, the smaller the inter-vehicle distance to the following vehicle, the more the gain K
_{Since 1} is set to a large value and the acceleration is further increased, when the following vehicle is approaching the own vehicle, it is possible to accelerate with relatively large acceleration and quickly secure the distance to the following vehicle. Thus, the acceleration can be accurately set according to the inter-vehicle distance between the own vehicle and the following vehicle. The gain K ₁ may be previously set multiple gain in accordance with inter-vehicle distance to the following vehicle, selects the gain corresponding to the distance to the following vehicle used as the gain K _1, Further, if to change the gain K ₁ depending on the distance to the following vehicle, it is possible to perform vehicle speed control in accordance with the approaching state of the following vehicle, irrespective of the distance to the following vehicle, K _It may be a constant satisfying ₁ > 1.

At this time, there has been described a case where the target acceleration / deceleration G ^* is largely corrected when there is no preceding vehicle and the rear inter-vehicle distance L _R is smaller than the target rear inter-vehicle distance L _R ^*. The distance between your vehicle and your vehicle is
Even if the host vehicle accelerates greatly, it is a distance that can be regarded as not approaching the preceding vehicle, and the inter-vehicle distance between the host vehicle and the following vehicle is quickly secured by the following vehicle approaching The target acceleration / deceleration G ^* may be corrected when the distance is considered to be better.

The target front inter-vehicle distance L _F ^* corresponds to the front inter-vehicle distance threshold, the target rear inter-vehicle distance L _R ^* corresponds to the rear inter-vehicle distance threshold, and the processing in step S52 in FIG. The processing of calculating the limit front inter-vehicle distance _LF-LIM in the processing of step S55 corresponds to the distance target value calculating means and the rear inter-vehicle distance target value calculating means, and corresponds to the processing of steps S56 and S62. Corresponds to the correction means, and the processing in step S57 corresponds to the warning means.

Next, a fourth embodiment of the present invention will be described. The fourth embodiment is the same as the following control process in the third embodiment except that the process in step S44a is added and the process in step S43 is different. The same reference numerals are given and the detailed description is omitted. That is, as shown in FIG. 12, greater than the target vehicle speed V ^* is vehicle speed Vs in the process of step S42, and, the inter-vehicle distance L _R between the following vehicle in the process of step S43 is higher than the target rear inter-vehicle distance L _R ^* Like the form of transition to the third embodiment in step S44 when also small, which was largely corrected by multiplying the target deceleration G ^* of the gain K _1, based on the target corrected acceleration G ^* The vehicle speed is controlled to quickly accelerate and return to the set vehicle speed.

On the other hand, if the inter-vehicle distance L _R with the succeeding vehicle is greater than or equal to the target rear inter-vehicle distance L _R ^{* in} the process of step S43, the flow shifts to step S44a, where the gain K ₂ is multiplied. The vehicle speed control is performed based on the speed G ^* . The gain K ₂ is as shown in a characteristic diagram of FIG. 13, K ₂ <a 1 and the rear inter-vehicle distance L _R is set as large a small value. Note that the gain K ₂ is “1”
It may be a smaller constant.

Therefore, the target acceleration / deceleration G ^* has a gain K
The target acceleration G ^* by multiplying the ₂ is small correction, is and suppressed as the rear inter-vehicle distance L _R becomes large to a small value. That is, when the target vehicle speed V ^* is increased i.e. acceleration than vehicle speed Vs, the inter-vehicle distance L _R is the target rear inter-vehicle distance L _R ^* less than the following vehicle, when the following vehicle is relatively close Is the target acceleration / deceleration G ^*
The vehicle is accelerated relatively quickly to return to the set vehicle speed, and the inter-vehicle distance with the following vehicle is ensured. Conversely, the inter-vehicle distance L _R with the following vehicle becomes the target rear inter-vehicle distance L _R ^*. As described above, when the following vehicle is relatively far away, the vehicle is accelerated gently to return to the set vehicle speed, thereby preventing the driver from feeling uncomfortable.

At this time, the following distance L to the following vehicle
Since _R is enough to gain K ₁ is set to be smaller large, when the inter-vehicle distance to the following vehicle is short return quickly to the set vehicle speed by performing a rapid acceleration, when inter-vehicle distance to the following vehicle is long, compared The vehicle speed can be accelerated moderately to return to the set vehicle speed. Also, since so as to set large as the gain K ₂ inter-vehicle distance L _R is small with a subsequent vehicle, as the vehicle distance L _R between the following vehicle is long, discomfort to the driver by performing the gradual acceleration performs acceleration without, it is possible to ensure the inter-vehicle distance between the following vehicle headway distance L _R to go faster acceleration than as shorter of the following vehicle.

In this case, it is needless to say that the same operation and effect as those of the third embodiment can be obtained. Also, in this case, similarly to the third embodiment,
Correction of the target acceleration / deceleration ^* is the distance between the preceding vehicle and the own vehicle that can be regarded as not approaching the preceding vehicle even if the own vehicle accelerates greatly, and The target acceleration / deceleration G ^* may be corrected when the inter-vehicle distance to the following vehicle is such a possible distance that it is deemed that it is better to secure the inter-vehicle immediately after the following vehicle approaches.

[0112] The gain K ₁ and K ₂ may be set a plurality gain in accordance with inter-vehicle distance to the following vehicle, the gain K ₁ This selects the gain corresponding to the distance to the following vehicle, K may be used as a _2, also if to change the gain K _1, K ₂ in accordance with the distance to the following vehicle, it is possible to perform vehicle speed control in accordance with the approaching state of the following vehicle Regardless of the inter-vehicle distance to the following vehicle, a constant satisfying K ₁ > 1 and a constant satisfying K ₂ <1 may be used.

In each of the above embodiments, the case where the present invention is applied to a rear wheel drive vehicle has been described. However, the present invention is not limited to this, and the present invention can be applied to a front wheel drive vehicle or a four wheel drive vehicle. Further, in each of the above-described embodiments, the case has been described in which the arithmetic processing by software is performed by the tracking control controller 20. However, the present invention is not limited to this, and a combination of a function generator, a comparator, and an arithmetic unit is used. You may make it comprise by applying the hardware which consists of the comprised electronic circuit.

[0114] The brake actuator is
The case where the brake 7 is applied has been described.
It is not limited to this, and other
Of course, actuators can be applied.
Brake actuator electrically controlled other than dynamic pressure
Can be applied. In this case, the target braking pressure P _B
^*Calculate the command value of the target current etc.
Braking control that controls the brake actuator based on the value
What is necessary is just to output it to the control device 8.

Further, the case where the engine 2 is applied as the rotary drive source has been described. However, the present invention is not limited to this, and an electric motor can be applied.
It is also possible to apply to a hybrid vehicle using an engine and an electric motor.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a functional configuration of a tracking control controller.

FIG. 3 is a flowchart illustrating an example of a processing procedure of a follow-up traveling control process in a follow-up control controller.

FIG. 4 is a diagram showing a method of calculating a target vehicle speed V ^* .

FIG. 5 is a characteristic diagram showing a torque ratio calculation map showing a relationship between a speed ratio and a torque ratio.

FIG. 6 is a characteristic diagram showing a throttle opening calculation map showing a relationship between an engine rotation speed and an engine torque as a throttle opening parameter;

FIG. 7 is an explanatory diagram for explaining the operation of the present invention;

FIG. 8 is a flowchart illustrating an example of a processing procedure of a follow-up traveling control process according to the second embodiment.

FIG. 9 is a flowchart illustrating an example of a procedure of a follow-up traveling control process according to the third embodiment.

FIG. 10 is a flowchart illustrating an example of a processing procedure of a target inter-vehicle distance calculation processing in FIG. 9;

11 is a characteristic diagram showing characteristics of a gain K _1.

FIG. 12 is a flowchart illustrating an example of a procedure of a follow-up running control process according to a fourth embodiment.

13 is a characteristic diagram showing characteristics of the gain K _2.

[Explanation of symbols]

 2 Engine 7 Disc brake 8 Braking control device 9 Engine output control device 11 Throttle valve 12F Front inter-vehicle distance sensor 12R Back inter-vehicle distance sensor 13 Vehicle speed sensor 14 Set switch 15 Vehicle speed setting device 16 Throttle opening sensor 17 Engine speed sensor 18 Torque converter Output rotation speed sensor 20 Tracking controller

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G05D 1/02 G05D 1/02 X G08G 1/16 G08G 1/16 E (72) Inventor Ken Kimura Kanagawa Prefecture Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama-shi (72) Inventor Taku Takahama 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa F-term (reference) 3D044 AA04 AA25 AA35 AC03 AC05 AC21 AC26 AC28 AC59 AD02 AD17 AD21 AE04 AE14 AE19 AE21 3D046 BB18 CC02 EE01 GG02 GG06 HH17 HH20 HH22 JJ01 JJ02 JJ05 MM08 3G093 AA05 BA23 CB10 DA01 DA06 DB01 DB05 DB16 EA01 EB03 EB04 EB04 FA07 FA10 FA11 FB02 5H01 A01 FB02 5H180 A01 FB02 5H180 A0105 GG28 JJ01 LL03 LL07 LL11 LL14 LL15

Claims (10)

[Claims] An inter-vehicle distance detection unit configured to detect a speed of the host vehicle; an inter-vehicle target value calculation unit configured to calculate a target inter-vehicle distance between the preceding vehicle and the own vehicle; Inter-vehicle distance detecting means for detecting the inter-vehicle distance in front and the inter-vehicle distance between the following vehicle and the own vehicle, and the inter-vehicle distance detection value detected by the inter-vehicle distance detecting means is calculated by the inter-vehicle distance target value calculating means. Vehicle speed control means for controlling the speed of the own vehicle based on the own vehicle speed detected by the own vehicle speed detection means so as to be equal to or more than the inter-vehicle distance target value, and the inter-vehicle distance detection means When the detected rear inter-vehicle distance detection value is lower than the rear inter-vehicle distance threshold, the inter-vehicle distance between the host vehicle and the preceding vehicle is reduced within a range where the front inter-vehicle distance detection value does not fall below the front inter-vehicle distance threshold. Like Vehicle control system, characterized in that there. 2. An own vehicle speed detecting means for detecting a speed of the own vehicle; an inter-vehicle distance target value calculating means for calculating an inter-vehicle distance target value between the preceding vehicle and the own vehicle; A rear inter-vehicle distance target value calculating means for calculating a rear inter-vehicle distance target value, a front limit distance calculating means for calculating a preceding vehicle approach limit distance between the preceding vehicle and the own vehicle, and Inter-vehicle distance detecting means for detecting the inter-vehicle distance in front and the inter-vehicle distance between the following vehicle and the own vehicle, and the inter-vehicle distance detection value detected by the inter-vehicle distance detection means is the inter-vehicle distance target value calculating means. Vehicle speed control means for controlling the speed of the own vehicle based on the own vehicle speed detected by the own vehicle speed detection means so as to be equal to or more than the calculated inter-vehicle distance target value, wherein the inter-vehicle distance detection means The following distance detected by When the distance detection value is smaller than the rear inter-vehicle distance target value, a correction means is provided for correcting the inter-vehicle distance target value to a small value within a range where the front inter-vehicle distance detection value does not fall below the preceding vehicle approach limit distance. Travel control device for vehicles. 3. The rear inter-vehicle distance detection value when the front inter-vehicle distance detection value is larger than the inter-vehicle distance target value and the rear inter-vehicle distance detection value is smaller than the rear inter-vehicle distance target value. 3. The vehicle travel control device according to claim 2, wherein the inter-vehicle distance target value is corrected so as to become the rear inter-vehicle distance target value. 4. The inter-vehicle distance target value according to claim 3, wherein the correction means corrects the inter-vehicle distance target value within a range where the front inter-vehicle distance detection value does not fall below the inter-vehicle distance target value. Travel control device for vehicles. 5. The inter-vehicle distance target value is set to one-half of the sum of the front inter-vehicle distance detection value and the rear inter-vehicle distance detection value. 3. The travel control device for a vehicle according to 2. 6. An own-vehicle speed detecting means for detecting a speed of the own-vehicle; an inter-vehicle distance target value calculating means for calculating an inter-vehicle distance target value between the preceding vehicle and the own vehicle; Limit distance calculation means for calculating a preceding vehicle approach limit distance between the preceding vehicle and a following vehicle, and a forward inter-vehicle distance between the preceding vehicle and the own vehicle and the following vehicle and the own vehicle. An inter-vehicle distance detecting means for detecting a rear inter-vehicle distance between the vehicle and the host vehicle speed such that a detected inter-vehicle distance detected by the inter-vehicle distance detecting means is equal to or more than a target inter-vehicle distance calculated by the inter-vehicle distance target value calculating means. Vehicle speed control means for controlling the speed of the own vehicle based on the own vehicle speed detected by the detection means, wherein the detected following inter-vehicle distance detected by the inter-vehicle distance detection means is the following vehicle approach limit. If you go below the distance , The vehicle control system, characterized in that it comprises a proximity limit time correction means the front inter-vehicle distance detection value is corrected reduce the inter-vehicle distance target value does not fall below the preceding vehicle approach limit distance. 7. The approach limit correction means sets a half of the sum of the front inter-vehicle distance detection value and the rear inter-vehicle distance detection value as the inter-vehicle distance target value. The vehicle travel control device according to claim 6. 8. The vehicle according to claim 1, further comprising a warning unit that issues a warning to a following vehicle when the detected value of the distance between the rear vehicles falls below a warning generation threshold. Travel control device. 9. The vehicle speed control means, when the rear inter-vehicle distance detection value falls below a rear acceleration control threshold value and the front inter-vehicle distance detection value exceeds a front acceleration control threshold value, when the condition is not satisfied. The vehicle travel control device according to any one of claims 1 to 8, wherein the vehicle speed control is performed at an acceleration greater than the vehicle speed control. 10. The vehicle travel control device according to claim 9, wherein the vehicle speed control means performs the vehicle speed control at a larger acceleration as the detected value of the distance between the rear vehicles becomes smaller.