JP2002331851A - Vehicle-to-vehicle distance control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To complete the change control of the vehicle-to-vehicle distance without sense of incongruity to the low-μ road surface received by the road-to- vehicle communication. SOLUTION: The target vehicle-to-vehicle distance correction ΔLc according to the traveling speed V of the concerned vehicle is calculated, and added to the reference target vehicle-to-vehicle distance Lc0 according to the traveling speed V of the concerned vehicle to calculate the target vehicle-to-vehicle distance correction LcH, and the target vehicle-to-vehicle distance correction ΔLc is divided by the predetermined rate of change dLc to obtain the lane change control start timing Th. The point before the low μ section position Xm(n) by the timing Th is set to be the vehicle-to-vehicle distance control start position Xs, and when the position Xc of the concerned vehicle reaches the vehicle-to- vehicle distance control start position Xs, the target vehicle-to-vehicle distance Lx is set to be the target vehicle-to-vehicle distance correction LcH and the change control of the vehicle-to-vehicle distance is started to complete the change control of the vehicle-to-vehicle distance immediately before the low μsection position Xm(n) . When the concerned vehicle must be accelerated, the target acceleration limit value XgL may be set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art When there is no preceding vehicle, the vehicle travels in accordance with the traveling speed set by the occupant, and when there is a preceding vehicle, the distance between the vehicle and the preceding vehicle is detected, and at a speed lower than the speed set by the occupant, 2. Description of the Related Art An inter-vehicle distance control device has been proposed in which traveling control is performed in accordance with an inter-vehicle distance or a relative speed between a host vehicle and a preceding vehicle. In such an inter-vehicle distance control device, for example, one disclosed in Japanese Patent Application Laid-Open No. H10-320691 refers to the running speed when a preceding vehicle is present at the current position of the own vehicle, and sets this speed as an upper limit. The driving speed of the vehicle is controlled. That is, the traveling speed of the preceding vehicle that is following the vehicle is set to the upper limit speed of the own vehicle when the vehicle reaches the position. Further, in this conventional technology, the state of the road surface friction coefficient is detected, and when the road surface friction coefficient is small, that is, only when the vehicle is traveling on a low μ road surface, the reference speed is applied as an upper limit value. I have. Therefore, if the preceding vehicle decelerates on a low μ road surface for some reason, the traveling speed of the own vehicle is also reduced accordingly, and the traveling stability of the vehicle is improved. Also, in recent years, it has been proposed to provide information on the road environment, such as an accurate road surface friction coefficient state, from a so-called infrastructure.
Effective inter-vehicle distance control is performed.

[0003]

However, in the conventional inter-vehicle distance control apparatus, the traveling speed of the host vehicle can be reduced before the vehicle shifts to a road surface having a small road surface friction coefficient, but the inter-vehicle distance control is continued. Therefore, the vehicle speed once decelerated may be accelerated again to adjust the inter-vehicle distance. Then, in some cases, there is a possibility that the vehicle may shift to a road surface having a small road surface friction coefficient while accelerating, and the driver of the host vehicle feels a sense of discomfort. To avoid this, the deceleration timing of the running speed of the host vehicle may be advanced, but such an approach would increase the inter-vehicle distance before shifting to a road surface having a small road surface friction coefficient. The driver feels strange.

[0004] In order to solve the above-mentioned problems, the present invention sets the timing for starting deceleration control in accordance with the road surface condition and the traveling condition of the vehicle based on information on the road surface condition ahead of the vehicle obtained from the infrastructure or the like. It is an object of the present invention to provide an inter-vehicle distance control device that does not make the driver feel uncomfortable by setting the distance.

[0005]

To achieve the above object, an inter-vehicle distance control device according to a first aspect of the present invention comprises:
An inter-vehicle distance detecting means for detecting an inter-vehicle distance between the own vehicle and the preceding vehicle; and an inter-vehicle distance for controlling the speed of the own vehicle so that the inter-vehicle distance between the own vehicle and the preceding vehicle matches the target inter-vehicle distance. A control unit, an information receiving unit that receives information about a road surface state ahead of the host vehicle from an information providing device, and a target of the host vehicle and the preceding vehicle based on the information about the road surface state ahead of the host vehicle received by the information receiving unit. Target inter-vehicle distance setting means for setting the inter-vehicle distance, and setting start timing of the target inter-vehicle distance so that the control of the actual inter-vehicle distance is completed before the vehicle reaches the road surface in front of the vehicle whose road surface condition is changing. Control start timing setting means.

According to a second aspect of the present invention, there is provided the inter-vehicle distance control device according to the first aspect of the present invention, wherein the target inter-vehicle distance setting means sets the target inter-vehicle distance. And acceleration limiting means for limiting the acceleration of the own vehicle due to the above.
In the inter-vehicle distance control device according to claim 3 of the present invention, in the invention according to claim 1 or 2, the information receiving means changes at least a road surface friction coefficient state and a road surface state of a road surface in front of the host vehicle. It is characterized by receiving information on the distance to the road surface.

According to a fourth aspect of the present invention, there is provided an inter-vehicle distance control device according to the first to third aspects, further comprising relative speed detecting means for detecting a relative speed between the host vehicle and the preceding vehicle. The inter-vehicle distance control unit is configured to determine the inter-vehicle distance according to the inter-vehicle distance between the host vehicle and the preceding vehicle detected by the inter-vehicle distance detection unit and the relative speed between the own vehicle and the preceding vehicle detected by the relative speed detection unit. Control the traveling state of the host vehicle such that the vehicle speed matches the target inter-vehicle distance.

According to a fifth aspect of the present invention, there is provided an inter-vehicle distance control device according to the third or fourth aspect of the present invention, further comprising: own vehicle speed detecting means for detecting a running speed of the own vehicle;
The target inter-vehicle distance setting unit may set a target inter-vehicle distance based on at least the information on the road surface friction coefficient state received by the information receiving unit and the traveling speed of the own vehicle detected by the own vehicle speed detecting unit. It is a feature.

According to a sixth aspect of the present invention, there is provided the inter-vehicle distance control apparatus according to the fifth aspect, wherein the target inter-vehicle distance change rate is set when the target inter-vehicle distance is changed. Means for setting the target inter-vehicle distance based on the target inter-vehicle distance change rate set by the target inter-vehicle distance change rate setting means.

According to a seventh aspect of the present invention, there is provided the inter-vehicle distance control device according to the first to sixth aspects, wherein the target inter-vehicle distance change rate for setting the target inter-vehicle distance change rate when the target inter-vehicle distance is changed. Rate setting means, and own-vehicle speed detecting means for detecting a running speed of the own-vehicle, wherein the control start timing setting means includes a target inter-vehicle distance set by the target inter-vehicle distance setting means and the target inter-vehicle distance change rate. The setting start timing of the target inter-vehicle distance is set based on the target inter-vehicle distance change rate set by the setting means and the traveling speed of the own vehicle detected by the own vehicle speed detecting means.

According to a further aspect of the present invention, in the inter-vehicle distance control apparatus according to the sixth or seventh aspect of the present invention, the target inter-vehicle distance change rate setting means sets the earliest timing by the control start timing setting means. Even if the control is started, if the control of the inter-vehicle distance is not completed before reaching the road surface ahead of the own vehicle where the road surface condition is changing, the target inter-vehicle distance change rate is set to be large. is there.

According to a ninth aspect of the present invention, the inter-vehicle distance control device according to the first to eighth aspects includes an information presenting means for presenting information to an occupant. When the target inter-vehicle distance set by the target inter-vehicle distance setting means changes and the inter-vehicle distance is changed accordingly, information is presented to the information presenting means.

[0013]

According to the inter-vehicle distance control apparatus according to the first aspect of the present invention, the target inter-vehicle distance between the own vehicle and the preceding vehicle is set from the received information regarding the road surface condition ahead of the own vehicle. When the road surface condition is changed, the target inter-vehicle distance setting start timing is set so that the actual inter-vehicle distance control is completed before the vehicle reaches the road surface ahead of the own vehicle where the road surface condition is changing. By appropriately setting the start timing of the target inter-vehicle distance according to the driving conditions of the vehicle and the host vehicle, the control of the actual inter-vehicle distance until the vehicle reaches the road surface where the road surface condition changes is completed, and the occupant feels uncomfortable. Do not give.

Further, according to the inter-vehicle distance control device of the present invention, when the target inter-vehicle distance is set, the acceleration of the own vehicle is restricted, so that the road surface friction coefficient state is small. Also, the passenger does not feel uncomfortable when the vehicle shifts to. According to the inter-vehicle distance control device according to claim 3 of the present invention, since at least the information on the road surface friction coefficient state of the road surface ahead of the host vehicle and the distance to the road surface where the road surface condition changes is received, Thus, the setting start timing of the target inter-vehicle distance can be set appropriately.

According to the inter-vehicle distance control device of the present invention, according to the detected inter-vehicle distance between the host vehicle and the preceding vehicle and the relative speed between the host vehicle and the preceding vehicle,
Since the running state of the host vehicle is controlled such that the inter-vehicle distance matches the target inter-vehicle distance, accurate preceding vehicle following control can be performed. According to the inter-vehicle distance control device according to claim 5 of the present invention, the target inter-vehicle distance is set based on the received information on the road surface friction coefficient state and the traveling speed of the host vehicle, so that an appropriate target The distance between vehicles can be set.

Further, according to the inter-vehicle distance control apparatus according to the sixth aspect of the present invention, the target inter-vehicle distance is set based on the set target inter-vehicle distance change rate. Appropriate values can be set according to the friction coefficient state and the running state of the vehicle. According to the inter-vehicle distance control device according to claim 7 of the present invention, the target inter-vehicle distance is set based on the set target inter-vehicle distance, the set target inter-vehicle distance change rate, and the detected traveling speed of the own vehicle. Since the setting start timing is set, the inter-vehicle distance control until the road surface condition changes can be made more accurate.

Further, according to the inter-vehicle distance control device of the present invention, even if the control is started at the earliest timing, the control is performed until the vehicle arrives at the road surface in front of the vehicle whose road surface condition is changing. If the control of the following distance is not completed,
Because the target inter-vehicle distance change rate is set to be large,
Even if the ride comfort and vehicle behavior are slightly unstable, the speed of the host vehicle can be appropriately reduced before the road surface condition changes.

Further, according to the inter-vehicle distance control apparatus of the ninth aspect of the present invention, when the set inter-vehicle distance changes and the inter-vehicle distance is changed in accordance with the change, the content is presented as information. Therefore, the occupant can recognize the content of the control, and can further dispel the discomfort.

[0019]

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

The rotation state, torque, output and the like of the engine 2 can be controlled by an engine control device 11. Specifically, by adjusting the throttle valve opening, the idle valve opening, the ignition timing, the fuel injection amount, the fuel injection timing, and the like, the rotation state, torque, output, and the like of the engine can be controlled. The automatic transmission 3 can be controlled by a transmission control device 12. Specifically, by adjusting the working fluid pressure supplied to the clutch and the brake in the automatic transmission 3, the selected gear ratio can be changed to obtain a desired reduction ratio.

Each of the wheels 1FL to 1RR is connected to a wheel cylinder 4FL to a so-called disc brake.
4RR is provided. This wheel cylinder 4FL-4
RR depends on the supplied brake fluid pressure and each wheel 1FL-1.
This is for applying a braking force to the RR. And each wheel 1
The braking force applied to FL to 1RR is controlled by the braking fluid pressure control device 1
3 can be controlled. Specifically, for example, the braking fluid pressure is increased as in a driving force control device (TCS),
By reducing the brake fluid pressure as in an anti-skid control device (ABS), each wheel cylinder 4F
Adjust the brake fluid pressure to L ~ 4RR, each wheel 1FL ~ 1
The braking force on the RR can be controlled. The braking fluid pressure adjusted in the braking fluid pressure control device 13 is supplied from a master cylinder 22 which is boosted by depressing a brake pedal 21.

Each of these control devices controls the running state of the vehicle, and as a result, the acceleration / deceleration of the own vehicle,
The traveling state can be controlled by adjusting the longitudinal speed and the like. Of course, these control devices can be operated alone, but the overall functions are governed by an automatic travel control device 10 including inter-vehicle distance control and preceding vehicle following travel control. The automatic travel control device 10 performs various arithmetic processes to control the travel state of the vehicle, and thereby performs inter-vehicle distance control, preceding vehicle follow-up travel control, and the like.

The vehicle is provided with, for example, a CCD camera or the like, for example, a front state detecting device 16 for detecting a state in front of the vehicle, for example, a state of a traveling lane, presence or absence of a preceding vehicle, or a distance to the preceding vehicle, Wheel speed sensor 17 for detecting the rotational speed of each wheel 1FL-1RR, acceleration sensor 18 for detecting the longitudinal and lateral acceleration generated in the vehicle, brake fluid pressure sensor 19 for detecting the brake fluid pressure, and detecting the depression amount of the accelerator pedal The accelerator opening sensor 20 is provided. Further, the vehicle is provided with a manual switch 9 for adjusting the traveling state of the host vehicle by manual input from the driver. Further, the vehicle is provided with a display and a speaker 23 for presenting the contents of control by the automatic traveling control device 10 to an occupant, particularly a driver.

The vehicle is provided with a road-vehicle communication device 7 for communicating information with a road environment, a so-called infrastructure. In this road-vehicle communication device 7,
Of course, various information about roads and traffic is communicated,
Particularly important in the present embodiment is the state of the road surface friction coefficient.
The transmission of the road surface friction coefficient state is configured as shown in FIG. That is, the road ahead of the reference point O is divided into sections Xm of a predetermined length, the road surface friction coefficient μ of each section is detected by the road surface friction coefficient detector R, and the detected position Xm _(i the road surface friction coefficient mu _i) of that transmitted from the beacon B to the vehicle. When the road surface friction coefficient state information is received by the road-to-vehicle communication device 7, the target vehicle-to-vehicle distance change control start position Xs is calculated and set by calculation processing described later using the information, and the target vehicle-to-vehicle distance change control is performed from the position Xs. Starting, the target inter-vehicle distance is set so as to complete the inter-vehicle distance change control until the road surface friction coefficient μ _i reaches the section position Xm _(n) where the road surface friction coefficient μ _i changes to the low road surface friction coefficient μ _n. Control the travel control device.

Next, the calculation process of the following distance control performed in the automatic traveling control device 10 will be described with reference to the flowchart of FIG. This calculation processing is, for example, 10 ms
It is executed by a timer interrupt every predetermined sampling time ΔT set to about ec. In this flowchart, no particular communication step is provided.
The result obtained by the arithmetic processing is updated and stored in the storage device as needed, and necessary information and programs are read from the storage device as needed. Further, the above-described engine control device 1
1. Communication with the transmission control device 12 and the brake fluid pressure control device 13 is performed as needed, and necessary information and commands are bidirectionally exchanged as needed. Further, here, as shown in FIG.
It is assumed that the road surface friction coefficient μ _n decreases at m _(n) .

In this calculation process, first, in step S1,
The longitudinal acceleration Xg and the lateral acceleration Yg detected by the acceleration sensor 18, the wheel speed Vw _j (j = FL-RR) detected by the wheel speed sensor 17, the accelerator opening detected by the accelerator opening sensor 20 Acc, the brake fluid pressure Pm detected by the brake fluid pressure sensor 19, the set speed Vc set by the manual switch 9, the section position Xm _(i) received by the road-to-vehicle communication device 7, and each section Xm road surface frictional coefficient in mu _i and the reference point O reference position X
b, the inter-vehicle distance Lx from the preceding vehicle detected by the front state detection device 16 and the engine drive torque Tw controlled by the engine control device 11 are read.

Next, the process proceeds to step S2, in which the traveling speed V of the vehicle is determined from the average value of the front left and right wheel speeds Vw _FL and Vw _FR of the driven wheels among the wheel speeds Vw _j read in step S1. calculate. Next, the process proceeds to step S3, in which the difference between the current value Lx _(n) and the previous value Lx _(n-1) of the inter-vehicle distance to the preceding vehicle read in step S1 is divided by the predetermined sampling time ΔT. Then, the relative speed dLx between the own vehicle and the preceding vehicle is calculated.

[0028] Next, the process proceeds to step S4, and calculates the reference target inter-vehicle distance Lc ₀ corresponding to the running speed V of the vehicle calculated at step S2. Specifically, it is determined by multiplying the traveling speed V of the own vehicle by a predetermined control gain and adding a predetermined control constant thereto. The control gain and the control constant may be changeable, for example, according to the inter-vehicle distance required by the driver.

Next, the process proceeds to step S5, where
Section position Xm read in step S1_(i)And the road of each section Xm
Surface friction coefficient μ_iFrom the road surface friction coefficient μ
Of the road surface friction coefficient μ
If so, proceed to step S6; otherwise,
Shifts to step S11. In step S6,
Road friction coefficient μ read in step S1_iAnd said
According to the traveling speed V of the own vehicle calculated in step S2,
According to the control map of FIG. 4, the target inter-vehicle distance correction amount ΔLc
After the calculation, the process proceeds to step S7. Here,
Road friction coefficient μ_iAnd section position Xm_(i)And associate
Section position Xm_{(i )}Target inter-vehicle distance correction amount ΔLc at
It is calculated. The control map of FIG.
Friction coefficient μ_iBut relatively small, for example, set to about 0.2
Predetermined value μ_i1In the following areas, the target inter-vehicle distance correction amount Δ
Lc is the maximum target inter-vehicle distance correction amount ΔLc_MAXConstant
Road friction coefficient μ_iIs set to, for example, about 0.8
Relatively large predetermined value μ_i2In the above areas, the target following distance
The separation correction amount ΔLc is constant at “0”, and is relatively small.
Predetermined value μ_i1A relatively large predetermined value μ_i2Between the road surface
Friction coefficient μ_iTarget inter-vehicle distance correction amount ΔLc
Is set to decrease linearly. Also,
Target inter-vehicle distance correction amount maximum value ΔLc_MAXIs the own vehicle
Multiply the traveling speed V by the control gain and add the control constant to it.
Value. Therefore, the target inter-vehicle distance correction amount maximum value ΔLc
_MAXIs set larger as the traveling speed V of the own vehicle is higher.
It is. The target inter-vehicle distance correction amount ΔLc is
It may be further changed according to the state of the road.

In step S7, step S4
The target inter-vehicle distance correction amount ΔLc is added to the reference target inter-vehicle distance Lc ₀ calculated in the above to calculate a target inter-vehicle distance correction value Lc _H, and then the process proceeds to step S8. In step S8, the target inter-vehicle distance correction amount Δ calculated in step S6 is used.
Using Lc, the target inter-vehicle distance change control start timing Th is calculated according to the following equation (1), and then the process proceeds to step S9.

Th = ΔLc / dLc + Thm (1) Here, dLc in the expression is a target inter-vehicle distance change rate, and is a predetermined value set in advance in the present embodiment. Thm in the expression is a compensation amount of a response that changes according to a road environment such as an uphill or a downhill, or a running state of the own vehicle such as an engine rotation state and a brake operation state.

At the step S9, at the step S8
Target inter-vehicle distance change control start timing Th calculated in
And the traveling speed V of the own vehicle calculated in step S2.
And calculating the target inter-vehicle distance change start position Xs according to the following two equations using the section position Xm _(n) where the road surface friction coefficient μ _i read in step S1 is the low road surface friction coefficient μ _n. Move to S10.

Xs = Xm _(n) −Th · V (2) In the step S10, the start of the target inter-vehicle distance change control is determined, and then the process proceeds to the step S11. Specifically, the travel distance of the own vehicle after passing through the reference point O shown in FIG. 2 is calculated by an integral value of the travel speed of the own vehicle, and the calculated value is added to the position Xb of the reference point O. Then, the travel position Xc of the own vehicle is calculated. If the travel position Xc of the own vehicle is before the target inter-vehicle distance change start position Xs, that is, smaller, the change of the target inter-vehicle distance does not need to be started. Conversely, the travel position Xc of the own vehicle is the target inter-vehicle distance change start position. If it is ahead of Xs, that is, if it is larger than Xs, it is determined that it is necessary to start changing the target inter-vehicle distance.

In step S11, the target inter-vehicle distance Lc is set as follows. First, step S
If it is determined in step 5 that the road surface friction coefficient does not change on the front road surface, the reference target inter-vehicle distance Lc ₀ calculated in step S4 is set as the target inter-vehicle distance Lc. Further, when the road surface friction coefficient changes on the front road surface in step S5 and the target inter-vehicle distance Lc set at the previous sampling time is equal to or less than the target inter-vehicle distance correction value Lc _H calculated in step S7, Step S
A value obtained by adding the integrated value of the target inter-vehicle distance change rate dLc up to the present time to the reference target inter-vehicle distance Lc ₀ calculated in 4 is set as a new target inter-vehicle distance Lc. Further, in step S5, there is a change in the road surface friction coefficient on the front road surface, and the target inter-vehicle distance Lc set at the previous sampling time is the target inter-vehicle distance correction value Lc _H calculated in step S7.
If the above is the case, the target inter-vehicle distance Lc _H is set to the target inter-vehicle distance Lc.

Next, the routine proceeds to step S12, where the target vehicle speed Vs is calculated as follows. Here, first, a value obtained by multiplying a difference value between the target inter-vehicle distance Lc calculated in step S11 and the actual inter-vehicle distance Lx read in step S1 by a proportional control gain, and the relative speed dLx calculated in step S3 Is multiplied by a differential gain to calculate a reference target vehicle speed Vs ₀ , and this reference target vehicle speed Vs ₀ is calculated.
_The smaller one of ₀ and the set vehicle speed Vc read in step S1 is set as the target vehicle speed Vs.

Next, the flow shifts to step S14, where the aforementioned steps are performed.
The target vehicle speed Vs calculated in step S12 and step S12
For example, from the difference value with the traveling speed V of the own vehicle calculated in step 2,
Target acceleration X by PID (proportional-differential-integral) control
gs is calculated. Next, proceeding to step S15,
The target acceleration Xgs calculated in step S14 is negative
In other words, when deceleration is required, the target acceleration
Xgs multiplied by a brake specification coefficient;
The brake fluid pressure Pm read in S1 is multiplied by a brake specification coefficient.
The larger of the target braking fluid pressure Pw
s _jIs calculated as The brake specification coefficient is an example
For example, the friction coefficient between the disc rotor pads of each wheel,
Cylinder area, disk rotor effective diameter, tire rolling
It is a coefficient determined by the radius of rolling.

Next, the process proceeds to step S16. If the target acceleration Xgs calculated in step S14 is positive, that is, if acceleration is required, the target acceleration Xgs
gs multiplied by a driving system specification variable and the value obtained in step S1
The value obtained by multiplying the accelerator opening Acc read by the above with the driving system specification variable, whichever is greater, is the target driving torque Tes.
Is calculated as Note that the drive system specification variables are variables determined by, for example, gear inertia, reduction ratio, transmission efficiency, engine characteristics, and the like.

[0038] and then proceeds to step S17, toward the target brake fluid pressure Pws _j and the target drive torque Tes calculated at step S15 the braking fluid pressure control apparatus 13 and the engine control device 11, the transmission controller 12 And outputs an information presentation signal of target inter-vehicle distance control to the display and the speaker 23, and then returns to the main program. This display and speaker 2
For example, when the road surface friction coefficient on the front road surface is low, the information presentation by 3 is performed by presenting information by voice or display such as "The road surface is becoming slippery ahead" or by changing the target inter-vehicle distance. Before doing so, for example, a content such as "increase the distance between vehicles" may be presented by voice or display.

As described above, in the present embodiment, when the road surface friction coefficient μ of the front road surface changes, the target inter-vehicle distance correction amount ΔLc is calculated in accordance with, for example, the traveling speed V of the vehicle.
The target inter-vehicle distance correction amount ΔLc and the reference target inter-vehicle distance Lc
_The target inter-vehicle distance correction value Lc _H is calculated from ₀ and
The target inter-vehicle distance change control start timing Th is calculated from the target inter-vehicle distance correction amount ΔLc, and the target inter-vehicle distance change control start timing Th, the traveling speed V of the own vehicle, and the road surface friction coefficient μ _i received by the road-vehicle communication are calculated. The target inter-vehicle distance change control start position Xs is calculated from the section position Xm _{(n) at} which the low road surface friction coefficient μ _n is obtained.

Here, the time set at the previous sampling time is set.
The target inter-vehicle distance Lc is the target inter-vehicle distance correction value Lc._H
If it is less than or equal to, the reference target inter-vehicle distance Lc₀The goal
The sum of the integrated values of the inter-vehicle distance change rate dLc up to the present
The new target inter-vehicle distance Lc is set and the previous sampling
The target inter-vehicle distance Lc set at the time is the target inter-vehicle distance.
Correction value Lc_HIf it is above, the target inter-vehicle distance L
c_HIs set to the target inter-vehicle distance Lc. That is, the current eye
The target inter-vehicle distance Lc is equal to the target inter-vehicle distance correction value Lc._HShorter
The target inter-vehicle distance Lc is equal to the target inter-vehicle distance change rate d.
Lc is set longer by Lc, and the target inter-vehicle distance Lc becomes the target inter-vehicle distance.
Separation correction value Lc_HWhen it becomes, the value is held. And
The position Xc of the own vehicle is the target inter-vehicle distance change control start position Xs
Exceeds target brake fluid pressure Pws_jCalculate and set your own vehicle
Decelerate both or calculate and set the target drive torque Tes
The target inter-vehicle distance Lc is increased by accelerating the vehicle.
change. Therefore, the road surface friction coefficient μ_iIs low road friction coefficient
μ_nSection position Xm_{(n )}Just before the target inter-vehicle distance Lc
Change control can be completed and the low road friction coefficient
μ_nSection position Xm_(n)Cruising when moving to
It can be in line state.

FIG. 5A shows a road surface having a high road friction coefficient μ.
This shows a state of the preceding vehicle following travel control in which a preceding vehicle that is traveling at a constant speed is traveling at a constant speed with a constant inter-vehicle distance. At the front section position Xm _(n) , the road surface friction coefficient μ _i becomes the low road surface friction coefficient μ _n . As described above, in the present embodiment, it is possible to road surface friction coefficient mu _i has finished changing control of the target following distance Lc just before the low road surface friction coefficient mu _n become section position Xm _(n), FIG. 5e When the preceding vehicle shifts to the low road surface friction coefficient section position Xm _(n) at a constant speed as shown in FIG.
It can shift to _(n), and there is no discomfort. Further, even if the preceding vehicle that has moved to the low road surface friction coefficient section position Xm _(n) accelerates for some reason, as shown in FIG. 5f, the own vehicle is driven at a substantially constant speed and the low road surface friction coefficient section position Xm _{(n). )} , So there is no discomfort.

On the other hand, if the control for changing the target inter-vehicle distance is not performed, even if the preceding vehicle moves to the low road surface friction coefficient section position Xm _(n) at a constant speed, the inter-vehicle distance is kept constant as shown in FIG. 5B. Since the vehicle shifts to the low road surface friction coefficient section position Xm _(n) , there is a sense of discomfort. When the preceding vehicle that has moved to the low road surface friction coefficient section position Xm _(n) accelerates for some reason, as shown in FIG. 5c, the own vehicle accelerates to maintain a constant inter-vehicle distance. The transition to the section position Xm _(n) gives a feeling of strangeness. Conversely, before reaching the low road surface friction coefficient section position Xm _(n) ,
If the target inter-vehicle distance is increased while both the preceding vehicle and the host vehicle are still in the high road surface friction coefficient section, the host vehicle decelerates in the high road surface friction coefficient section, so that there is a sense of discomfort.

Further, the target inter-vehicle distance correction amount ΔLc and the target inter-vehicle distance change control start timing Th are set based on the road surface friction coefficient μ and the traveling speed V of the own vehicle, so that the inter-vehicle distance until the road surface condition changes is set. Distance control can be made more accurate. In the embodiment, the maximum value ΔL of the target inter-vehicle distance correction amount ΔLc is used.
c _MAX is a value corresponding only to the traveling speed V of the own vehicle,
The target inter-vehicle distance correction amount maximum value ΔLc _MAX , that is, the target inter-vehicle distance correction amount ΔLc itself may be changed according to the predicted traveling state of the host vehicle. For example, if the information obtained by the road-to-vehicle communication includes, for example, the curvature of the road in addition to the road surface friction coefficient, the own vehicle may enter the road surface with a low road surface friction coefficient during turning. In such a case, it is better to set the inter-vehicle distance to be longer. For example, the target inter-vehicle distance correction amount is determined in accordance with the lateral acceleration during turning predicted from the current traveling speed V of the own vehicle and the curvature of the curved road. it may be increased up to values ΔLc _MAX. Such information can be obtained not only from road-to-vehicle communication but also from, for example, a navigation system and map information.

Next, a description will be given of a second embodiment of the following distance control apparatus according to the present invention. The schematic configuration of the vehicle in this embodiment is the same as that in FIG. 1 of the first embodiment, and a detailed description thereof will be omitted. Also, the logic for controlling the following distance is substantially the same as that of the flowchart of FIG. 3 of the first embodiment, and the description of the same steps will be omitted.

In this embodiment, the method of calculating the target inter-vehicle distance change control start timing Th performed in step S8 of the calculation processing of FIG. 3 is changed as follows.
As will be described later, the target inter-vehicle distance change rate dLc used for the calculation is changed according to the situation. First, for example, as (in the drawing the low μ road surface) lower road friction coefficient road surface from time t ₀₂ as shown in FIG. 6 moves to the traveling speed of the own vehicle, earlier has become a steady state is desired.
For example, in this example, assuming that the target inter-vehicle distance change control as described above from the time t ₀₀ is started, the period from time t ₀₀ to time t ₀₂ corresponding to the target inter-vehicle distance change control start timing Th . In this embodiment, the target inter-vehicle distance change control start timing Th is set in two stages,
That is, the first step timing Th ₁ from time t ₀₀ to the target inter-vehicle distance Lc reaches the target inter-vehicle distance correction value Lc _H to the time t _01, the inter-vehicle distance Lx is the target inter-vehicle distance Lc, that is, the target inter-vehicle distance correction value Lc _H From time t ₀₁ to time t ₀₂
Divided into a second stage timing Th ₂ up. Of these, the first step timing Th _1, the inter-vehicle distance Lx corresponding to the output is, the lamp in response to the target inter-vehicle distance Lc corresponding to the input, the second stage timing Th _2, the target inter-vehicle distance is the inter-vehicle distance Lx The timings Th ₁ and Th ₂ are calculated and set as those which respond to the index to Lc. Incidentally, the first step timing Th ₁ is the value of the difference value obtained by dividing by the vehicle distance change rate dLc between the target inter-vehicle distance correction value Lc _H and the reference target inter-vehicle distance Lc _0.

As shown in FIG. 6B, when the target inter-vehicle distance Lc is uniformly changed from the reference target inter-vehicle distance Lc _{0 at the} target inter-vehicle distance change rate dLc as shown in FIG.
At a time later than the response to the inter-vehicle distance Lx is changed smoothly, here, when changing the target following distance changing rate dLc a target inter-vehicle distance Lc from the time t _00, as described above, the inter-vehicle distance Lx at time t ₀₁ There shall be reached inter-vehicle distance Lx _t. Therefore, the function _{f (dLc, t 01 -t 00} ) to, based on the lamp response, arguments dLc, from t ₀₁ -t _00, the function for obtaining the difference value and the arrival inter-vehicle distance Lx _t and the reference target inter-vehicle distance Lc ₀ when, the reach the inter-vehicle distance Lx _t is expressed by the following three equations.

[0047] _{Lx t = f (dLc, t} 01 -t 00) + Lc 0 ......... (3) Indesharu response, as shown in FIG. 6c, stepwise the target inter-vehicle distance Lc from the arrival vehicle distance Lx _t This is a response in which the inter-vehicle distance Lx changes smoothly after the change, and here, when the target inter-vehicle distance Lc is changed stepwise from the time t ₀₁ as described above, the inter-vehicle distance Lx is changed at the time t _01. It is assumed that Lx becomes the target inter-vehicle distance Lc. Therefore, the function h (Lc _H −Lx _t ) is calculated from the argument Lc _H −Lx _{t at} time t ₀₂ −t based on the index response.
₀₁ , the second stage timing T
h ₂ is given by the following equation 4.

[0048] Th_Two= T₀₂-T₀₁= H (Lc_H-Lx_t) ...... (4) First stage timing Th thus obtained₁And the second
Two-stage timing Th _TwoTarget inter-vehicle distance change system based on sum
By calculating the start timing Th,
It is necessary to perform more accurate and smooth target inter-vehicle distance change control.
Can be. In consideration of the above-mentioned response compensation amount Thm,
You may.

In this embodiment, the target inter-vehicle distance change rate dLc is changed as described above. That is, for example, the timing of obtaining the information about the road surface friction coefficient mu _i is slow, for example, a distance of the road surface friction coefficient mu _i until low road surface friction coefficient mu _n become section position Xm _(n) is shortened, the target inter-vehicle distance change rate If dLc is kept constant, the position Xc of the host vehicle is located ahead of the target inter-vehicle distance change control start position Xs, and even if the target inter-vehicle distance change control is started immediately, the low road surface The inter-vehicle distance change control cannot be completed before the shift to the friction coefficient section position Xm _(n) .

Therefore, in this embodiment, when the position Xc of the host vehicle is located ahead of the target inter-vehicle distance change control start position Xs, that is, the position Xc of the host vehicle is larger than the target inter-vehicle distance change control start position Xs. While gradually increasing the target inter-vehicle distance change rate dLc,
The calculation process from step S8 to step S10 of the calculation process is repeated, and the target inter-vehicle distance is changed using the target inter-vehicle distance change rate dLc when the position Xc of the own vehicle becomes equal to or less than the target inter-vehicle distance change control start position Xs. The control start timing Th and the target inter-vehicle distance change control start position Xs are calculated, and the target vehicle speed Vs is calculated in step S12 of the calculation processing in FIG. This results in the target inter-vehicle distance Lc being changed to the target inter-vehicle distance correction value Lc _H as shown in FIG.
Is to speed up the timing of increasing the vehicle speed, and at the same time, increase the amount of deceleration of the traveling speed of the own vehicle,
It is possible to recover the delay of the information acquisition timing of the road surface friction coefficient μ _i and to complete the control for changing the target inter-vehicle distance before shifting to, for example, the low road surface friction coefficient section position Xm _(n) .

Next, a third embodiment of the inter-vehicle distance control device according to the present invention will be described. The schematic configuration of the vehicle in this embodiment is the same as that in FIG. 1 of the first embodiment, and a detailed description thereof will be omitted. In this embodiment, the arithmetic processing for the following distance control is changed to that of FIG. 8 instead of the flowchart of FIG. 3 of the first embodiment. The calculation processing of FIG. 8 is similar to the calculation processing of FIG. Specifically, step S1 of the arithmetic processing of FIG.
Step S13 is newly added between Step 2 and Step S14, and Step S14 of the calculation processing in FIG. 3 is only changed to Step S14 ', and the others are completely equivalent.

In step S13, the control map shown in FIG.
Road friction coefficient μ_iTarget acceleration limit according to
Value Xg_LSet. In this control map, the road friction
Several μ _iIs the relatively small predetermined value μ._i1Eyes in the following areas
Target acceleration limit value Xg_LIs a relatively small predetermined value Xg_LMINone
Constant, the coefficient of road friction μ_iIs the relatively large predetermined value
μ_i2In the above area, the target acceleration limit value Xg_LIs relatively large
The predetermined value Xg_LMAXConstant, coefficient of road friction μ_iBefore
A relatively small predetermined value μ_i1A relatively large predetermined value μ_i2
Up to the road surface friction coefficient μ_iGoals with increasing
Acceleration limit value Xg_LIs also set to increase linearly
ing. That is, the road surface friction coefficient μ_iIs larger,
Speed limit value Xg_LWill also be set large.

In the step S14 ',
3. Target acceleration calculated in step S14 of the calculation processing in FIG.
And the target acceleration calculated and set in step S13.
Limit value Xg_LWhichever is smaller is the target acceleration X
gs. Therefore, in this embodiment, for example,
The low road surface friction coefficient section position Xg_(n)Self when entering
The acceleration of the vehicle is set to the target acceleration limit value Xg._LLimited by
Do not enter the road surface with low road friction coefficient with acceleration higher than that
Can be done. As described above, the first and second
In the second embodiment, the preceding vehicle is located at the low road surface friction coefficient section position X.
m _(n)Even if you accelerate after entering the vehicle, your vehicle is almost constant speed
The vehicle can travel, but the preceding vehicle continues to accelerate.
Then, in order to maintain the target inter-vehicle distance Lc,
Accelerate and keep the low road surface friction coefficient section position Xm_(n)Proceed to
It is possible to enter. In contrast, in this embodiment,
Is the low road surface friction coefficient section position Xm_(n)Of own vehicle in
The target acceleration Xgs is set to the target acceleration limit value Xg._LRestricted by
By doing, the low road surface friction coefficient section position Xm_(n)Self
It is possible to prevent the vehicle from entering while accelerating.
Wear.

In the above embodiment, the so-called feedback control is used for controlling the speed of the host vehicle based on the inter-vehicle distance to the preceding vehicle.
9. A combination of feedback control and feedforward control may be applied, as described in the November issue (p98-p103, "Development of an Automatic Control System for Inter-vehicle Control", Iijima et al.). That is, the present invention relates to the control start timing when the target inter-vehicle distance is changed, and various control rules can be applied to the inter-vehicle distance control.

The object of road-vehicle communication is not limited to beacons, and various objects can be applied.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of a configuration for receiving a road surface friction coefficient by road-to-vehicle communication.

FIG. 3 is a flowchart showing a calculation process for an inter-vehicle distance control performed by the automatic traveling control device of FIG. 1;

FIG. 4 is a control map used in the calculation processing of FIG. 3;

FIG. 5 is a diagram illustrating the operation of the calculation processing of FIG. 3;

FIG. 6 is an explanatory diagram of a method of calculating a target inter-vehicle distance change control start timing.

FIG. 7 is an explanatory diagram of a target inter-vehicle distance when a target inter-vehicle distance change rate is changed.

FIG. 8 is a flowchart showing another calculation process for the following distance control performed by the automatic traveling control device of FIG. 1;

FIG. 9 is a control map used in the calculation processing of FIG. 8;

[Explanation of symbols]

 1FL-1RR is a wheel 2 is an engine 3 is an automatic transmission 4FL-4RR is a wheel cylinder 7 is an inter-vehicle communication device 9 is a manual switch 10 is an automatic traveling control device 11 is an engine control device 12 is a transmission control device 13 is a braking fluid The pressure control device 16 is a front state detection device 17 is a wheel speed sensor 18 is an acceleration sensor 19 is a braking fluid pressure sensor 20 is an accelerator opening sensor 21 is a brake pedal 22 is a master cylinder 23 is a display and a speaker

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60R 21/00 628 B60R 21/00 628E 628F 630 630D F02D 29/02 301 F02D 29/02 301D G08G 1/09 G08G 1/09 D 1/16 1/16 E (72) Inventor Hiromitsu Toyoda 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa F-term in Nissan Motor Co., Ltd. 3D044 AA25 AB01 AC16 AC24 AC26 AC28 AC55 AC56 AC59 AD04 AD17 AD21 AE01 AE04 AE14 AE15 AE21 3G093 AA01 BA23 CB10 DA06 DB02 DB05 DB15 DB16 DB18 EA05 EA09 EB03 EB04 EC01 EC04 FA02 FA04 FA07 FA08 FA11 FA12 FB01 FB02 FB05 5H180 AA01 CC04 CC12 FF05 LL13 FF27 LL27

Claims (9)

[Claims] 1. An inter-vehicle distance detecting means for detecting an inter-vehicle distance between a host vehicle and a preceding vehicle, and controlling the speed of the host vehicle so that the inter-vehicle distance between the host vehicle and the preceding vehicle coincides with a target inter-vehicle distance. The inter-vehicle distance control means that controls the vehicle, information receiving means that receives information about the road surface state ahead of the host vehicle from the information providing device, and the host vehicle from the information about the road surface state ahead of the host vehicle received by the information receiving unit Target inter-vehicle distance setting means for setting a target inter-vehicle distance with a preceding vehicle, and the target inter-vehicle distance so that the control of the actual inter-vehicle distance is completed before reaching the road surface in front of the own vehicle in which the road surface condition is changing. An inter-vehicle distance control device comprising: control start timing setting means for setting a setting start timing. 2. The vehicle according to claim 1, further comprising: acceleration limiting means for limiting acceleration of the own vehicle by said inter-vehicle distance control means when said target inter-vehicle distance setting means sets the target inter-vehicle distance. The following distance control apparatus. 3. The information receiving unit according to claim 1, wherein the information receiving unit receives at least information on a road surface friction coefficient state of a road surface ahead of the host vehicle and a distance to a road surface on which the road surface state changes. Inter-vehicle distance control device. 4. A vehicle according to claim 1, further comprising a relative speed detecting means for detecting a relative speed between the host vehicle and the preceding vehicle, wherein said inter-vehicle distance control means includes:
The inter-vehicle distance matches the target inter-vehicle distance according to the inter-vehicle distance between the own vehicle and the preceding vehicle detected by the inter-vehicle distance detecting means and the relative speed between the own vehicle and the preceding vehicle detected by the relative speed detecting means. The inter-vehicle distance control device according to any one of claims 1 to 3, wherein the running state of the own vehicle is controlled so as to perform the control. 5. An own-vehicle speed detecting means for detecting a running speed of the own-vehicle, wherein said target inter-vehicle distance setting means includes information on a road surface friction coefficient state received by at least said information receiving means and said own-vehicle speed detecting means. The inter-vehicle distance control device according to claim 3 or 4, wherein the target inter-vehicle distance is set based on the traveling speed of the own vehicle detected by the means. 6. A target inter-vehicle distance change rate setting means for setting a target inter-vehicle distance change rate when changing a target inter-vehicle distance, wherein the target inter-vehicle distance setting means is set by the target inter-vehicle distance change rate setting means. The target inter-vehicle distance is set based on the target inter-vehicle distance change rate.
4. The following distance control apparatus. 7. A control method comprising: a target inter-vehicle distance change rate setting means for setting a target inter-vehicle distance change rate when changing a target inter-vehicle distance; and a host vehicle speed detecting means for detecting a running speed of the host vehicle. The timing setting means includes: a target inter-vehicle distance set by the target inter-vehicle distance setting means; a target inter-vehicle distance change rate set by the target inter-vehicle distance change rate setting means; The inter-vehicle distance control device according to any one of claims 1 to 6, wherein the setting start timing of the target inter-vehicle distance is set based on the traveling speed. 8. The target inter-vehicle distance change rate setting means, even if the control is started at the earliest timing by the control start timing setting means, until the vehicle reaches a road surface in front of the vehicle whose road surface condition is changing. 8. The inter-vehicle distance control device according to claim 6, wherein the target inter-vehicle distance change rate is set to be large when the inter-vehicle distance control is not completed. 9. An inter-vehicle distance control means for presenting information to an occupant, wherein the inter-vehicle distance control means changes a target inter-vehicle distance set by the target inter-vehicle distance setting means and changes the inter-vehicle distance accordingly. The inter-vehicle distance control device according to any one of claims 1 to 8, wherein the content is presented to the information presentation means.