JPH11254995A - Vehicle running control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle running control device for running a vehicle following a preceding vehicle while maintaining an inter-vehicle distance therebetween, which restrains variation in the posture of a vehicle when the preceding vehicle is continuously braked so as to come to a stop. SOLUTION: When a preceding vehicle is decelerated in such a condition that follow-up running is controlled while an inter-vehicle distance is maintained with respect to the preceding vehicle, a desired braking pressure PB* is calculated from the inter-vehicle distance, and a depressurizing instruction value PST is calculated. If the inter-vehicle distance D exceeds a safe-stop inter-vehicle distance DST, and if the depressurization instruction value PST exceeds the desired braking pressure PB*, the depressurization is controlled in accordance with the depressurizing instruction value PST, instead of the desired braking pressure PB*, in order to shift the operating condition into a moderate acceleration condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular travel control device which controls the speed of a vehicle following a preceding vehicle while maintaining a distance between the vehicle and the preceding vehicle.

[0002]

2. Description of the Related Art As a conventional traveling control device for a vehicle, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. H5-274036.

In this conventional example, a target vehicle speed is set to a value preset in the apparatus or a value arbitrarily set by a driver, and D> Dt based on the detected inter-vehicle distance D and the target inter-vehicle distance Dt. When the vehicle speed V is equal to the target vehicle speed Vt, acceleration control is performed so that the vehicle speed V matches the target vehicle speed Vt. When D ≦ Dt, the inter-vehicle distance D and the target vehicle-to-vehicle distance Dt are determined based on the deviation between the vehicle distance D and the target vehicle-to-vehicle distance Dt. There is described a vehicle speed control device that performs deceleration control by applying a braking force calculated as described above.

[0004]

However, in the above-described conventional vehicle speed control device, when the inter-vehicle distance of the vehicle is smaller than the target inter-vehicle distance, the deceleration control is performed by applying the braking force. When the preceding vehicle exerts a braking force and the braking state is continuously stopped, the succeeding vehicle is stopped while maintaining a large deceleration by applying the braking force according to the following distance. There is an unsolved problem that a large swing-back from a so-called nose dive state occurs in which the front wheel side sinks when the vehicle stops, and the ride comfort deteriorates.

Accordingly, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and when the preceding vehicle is brought into a stopped state by generating a braking force from a running state, the preceding vehicle is stopped. It is an object of the present invention to provide a traveling control device for a vehicle that suppresses swinging back from a nose dive state that occurs when the vehicle is following the vehicle and stops, thereby improving ride comfort.

[0006]

According to a first aspect of the present invention, there is provided a vehicle travel control apparatus for controlling a speed of following a preceding vehicle while maintaining a predetermined distance between the vehicle and the preceding vehicle. In the vehicle travel control device as described above, an inter-vehicle distance detection unit that detects an inter-vehicle distance with a preceding vehicle, and a target acceleration / deceleration is calculated based on the inter-vehicle distance and the target inter-vehicle distance detected by the inter-vehicle distance detection unit. Traveling control means for performing follow-up traveling control in accordance with the calculated target acceleration / deceleration; and the traveling control means when the vehicle speed near stop comes to a deceleration control based on the target deceleration. And a deceleration correcting means for correcting the deceleration set in (1) to a slow deceleration.

According to the first aspect of the present invention, the deceleration is corrected to a slow deceleration when the vehicle speed becomes close to the stop, so that the amount of nose dive generated in the vehicle is suppressed, and the swing at the time of the stop is controlled. A change in the attitude of the vehicle due to the return can be suppressed.

According to a second aspect of the present invention, in the vehicle traveling control apparatus according to the first aspect, when the traveling control means calculates the target deceleration, the target braking corresponding to the target deceleration is calculated. Pressure, and the braking pressure of the braking cylinder is controlled in accordance with the target braking pressure. The deceleration correcting means determines that the pressure reduction command value calculated as a function of the vehicle speed is equal to or less than the target braking pressure. In such a case, the target braking pressure is corrected to the pressure-decrease command value when the pressure is reduced.

According to the second aspect of the present invention, the pressure reduction control can be performed based on the pressure reduction command value which is a function of the vehicle speed below the vehicle speed near the stop, and the deceleration is gradually reduced as the vehicle speed decreases. Can be reduced.

Further, in the vehicle traveling control device according to a third aspect, in the invention according to the first or second aspect, the deceleration correcting means is configured such that the inter-vehicle distance detected by the inter-vehicle distance detecting means is equal to or greater than a safe stop inter-vehicle distance. It is characterized in that it is configured to change to the slow deceleration at a certain time.

In the invention according to the third aspect, the deceleration is changed to the slow deceleration when the inter-vehicle distance is equal to or longer than the safety stop inter-vehicle distance. Therefore, priority can be given to securing the inter-vehicle distance over ride comfort.

Further, in the vehicle traveling control device according to a fourth aspect of the present invention, in the invention according to the third aspect, the safe inter-vehicle distance is a sum of a vehicle speed multiplied by a pressure reduction change rate and a stop maintaining braking pressure. It is characterized in that it is calculated by integrating the own vehicle speed obtained by integrating the deceleration divided by the deceleration / brake pressure conversion gain up to the time required for stopping.

In the invention according to the fourth aspect, it is possible to determine an optimum safe stop inter-vehicle distance in accordance with the vehicle speed, and it is possible to accurately determine whether or not deceleration correction control is to be performed.

[0014]

According to the first aspect of the present invention, when the preceding vehicle decelerates and stops during the follow-up control for following the preceding vehicle, and when the vehicle speed near the stop is reached, the traveling control means is used. Since the set deceleration is corrected to the slow deceleration, the deceleration at the time of stop is suppressed to a small value, the nose dive amount at the time of stop is suppressed, and the occurrence of swingback can be suppressed. And the ride comfort can be improved.

According to the second aspect of the invention, the traveling control means calculates a target braking pressure corresponding to the target deceleration, and controls the braking pressure of the braking cylinder in accordance with the target braking pressure. The deceleration correcting means is configured to correct the target braking pressure to the pressure reducing command value when the pressure reducing command value calculated as a function of the vehicle speed becomes equal to or less than the target braking pressure. When the vehicle stops, the braking pressure is corrected to a pressure reducing command value calculated as a function of the vehicle speed in the vicinity of the stop, so that the deceleration decreases as the vehicle speed decreases, and the nose dive amount at the time of stop is reliably reduced. Thus, the effect that the swing back can be surely suppressed can be obtained.

Further, according to the third aspect of the present invention, the deceleration correction means changes the deceleration to a slow deceleration when the inter-vehicle distance detected by the inter-vehicle distance detection means is equal to or longer than the safe stop inter-vehicle distance. Therefore, it is possible to perform the change to the slow deceleration while always securing the safety stop inter-vehicle distance, and to obtain the effect that the deceleration control can be performed while maintaining the inter-vehicle distance.

According to the fourth aspect of the present invention, the safe stop inter-vehicle distance is obtained by dividing the sum of the own vehicle speed multiplied by the pressure reduction change rate and the stop maintaining brake pressure by the deceleration / brake pressure conversion gain. Since the self-vehicle speed obtained by integrating the deceleration is calculated by integrating the time required until the vehicle stops, an effect is obtained that an optimum safe stop inter-vehicle distance according to the vehicle speed can be set.

[0018]

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

Front wheels 1FL, 1FR and rear wheels 1RL, 1R
R is provided with a disc brake 7 for generating a braking force, and the braking oil pressure of the disc brake 7 is controlled by a braking control device 8.

Here, the braking control device 8 generates a braking oil pressure in response to depression of a brake pedal (not shown) and generates a braking oil pressure by reducing the pressure in accordance with a pressure reducing command value from the traveling control controller 20. It is configured as follows.

The engine 2 is provided with an engine output control device 9 for controlling the output. The engine output control device 9 controls the engine output by controlling the engine speed by adjusting the opening of the throttle valve and adjusting the opening of the idle control valve to control the engine speed by controlling the engine speed. Although a control method is conceivable, in the present embodiment, a method of adjusting the opening of the throttle valve is employed.

Further, the automatic transmission 3 is provided with a transmission control device 10 for controlling the shift position. When an up / down shift command value TS is input from a travel control controller 20 described later, the transmission control device 10 performs up shift or down shift control of the shift position of the automatic transmission 3 in response to the input. Is configured.

On the other hand, an inter-vehicle distance sensor 12 comprising a radar device as inter-vehicle distance detecting means for detecting an inter-vehicle distance between the vehicle and a preceding vehicle is provided below the vehicle body on the front side of the vehicle. Wheel speed sensors 13L and 13R for detecting wheel speeds of the wheels 1RL and 1RR are provided.

The output signals of the inter-vehicle distance sensor 12 and the wheel speed sensors 13L and 13R are input to the travel control controller 20, and the travel control controller 2
By 0, the inter-vehicle distance detected by inter-vehicle distance sensor 12 L, the wheel speed sensors 13L, a wheel speed Vw L detected by _13R, based on Vw _R, brake controller 8, engine output controller 9 and the transmission controller 10 By performing the following control while maintaining an appropriate inter-vehicle distance with the preceding vehicle, the following control is performed.When the preceding vehicle shifts to a deceleration state during the following driving control, the control is performed in accordance with the control. A power control is performed, and a target braking pressure P ^* calculated based on the following distance is calculated as a function of the vehicle speed.
_{When the} pressure exceeds _{ST, the} pressure reduction command value P _ST is used instead of the target braking pressure P ^*.
, And is controlled to a slow deceleration state.

Next, the operation of the above-described embodiment will be described with the traveling control processing shown in FIG. This traveling control processing is performed first in step S
In step 1, the inter-vehicle distance D from the actual preceding vehicle detected by the inter-vehicle distance sensor 12 is read. Then, the process proceeds to step S2, in which the wheel speeds Vw _{L and} Vw _R detected by the wheel speed sensors 13L and 13R are read. The vehicle speed V (n) is calculated by calculating the average value.

Next, the process proceeds to step S3, where the following is calculated from the own vehicle speed V (n) and the time T ₀ (inter-vehicle time) required for the own vehicle to reach the current position L ₀ [m] behind the preceding vehicle. The target inter-vehicle distance D ^* between the preceding vehicle and the host vehicle is calculated according to the equation (1).

D ^* (n) = V (n) × T ₀ + D ₀ (1) Here, D ₀ is the inter-vehicle distance when stopped. By adopting the concept of inter-vehicle time in equation (1), the inter-vehicle distance is set to increase as the vehicle speed increases.

Then, the process proceeds to step S4 to determine whether or not the inter-vehicle distance D (n) is less than or equal to the target inter-vehicle distance D ^* (n). If D (n)> D ^* (n), then Inter-vehicle distance D (n)
Has exceeded the target inter-vehicle distance D ^* (n), it is determined that it is possible to reduce the inter-vehicle distance as an acceleration state, and the process proceeds to step S5. Based on the target vehicle speed V ^* set in advance, the following ( The target acceleration / deceleration G ^* is calculated according to the equation (2), and the calculated target acceleration / deceleration G ^* is updated and stored in the acceleration / deceleration storage area of the memory, and then the process proceeds to step S7.

[0029] _{^{G * = K A × (V}} * -V (n)) + L A ............ (2) where, K _A and L _A are constants. On the other hand, step S
When the determination result of 4 is D (n) ≦ D ^* (n), it is determined that the inter-vehicle distance D (n) is shorter than the target inter-vehicle distance D ^* (n), and it is necessary to increase the inter-vehicle distance as a deceleration state. Then, the process proceeds to step S6, the target acceleration / deceleration G ^* is calculated based on the following equation (3), and this is updated and stored in the acceleration / deceleration storage area of the memory, and then the process proceeds to step S7.

[0030] _{^{G * = K B × (D}} (n) -D * (n)) + L B ............ (3) where, K _B and L _B are constants. In step S7, the target acceleration / deceleration G stored in the acceleration / deceleration storage area
Based on ^* , a throttle opening command value θ for the engine control device 9 and an up / down shift command value TS for the transmission control device 10 are calculated, and an engine control process for outputting these is executed, and then the process proceeds to step S8. .

Here, the throttle opening command value θ is equal to the target acceleration / deceleration G in the acceleration state where the target acceleration / deceleration G ^* is positive.
^* To calculate the throttle opening degree change amount Δθ to increases in the positive direction with an increase in the target deceleration is until to reach a predetermined value -G _S from "0" when the target deceleration G ^* is negative The throttle opening change amount Δθ that increases in the negative direction in accordance with the increase of G ^{* in} the negative direction is calculated, and the calculated throttle opening change amount Δθ is added to the current throttle opening command value θ to obtain a new throttle opening command value θ. such calculates the throttle opening command value theta, the target deceleration G ^* is set to "0" or a value in the vicinity of the throttle opening command value theta when exceeding the predetermined value -G _S.

The up / down shift command value TS
Is an up / down shift command value of the automatic transmission 3 based on the calculated throttle opening command value θ and the vehicle speed V (n) with reference to a shift control map similar to the shift control in a normal automatic transmission. Calculate TS.

In step S8, the throttle opening command value θ for the engine control device 9 and the up / down shift command value TS for the transmission control device 10 are determined based on the target acceleration / deceleration G ^* stored in the acceleration / deceleration storage area. After performing the braking control process of calculating and outputting these, the process returns to step S1.

As shown in FIG. 3, a specific example of the braking control process is as follows. First, a target acceleration / deceleration G ^* is read in step S8a, and then the process proceeds to step S8b, where a memory is stored based on the target acceleration / deceleration G ^*. The target braking pressure P _B ^* is calculated with reference to the braking pressure calculation map shown in FIG. The slope in FIG. 4 represents a conversion gain K _P for converting a deceleration described later into a braking pressure.

Here, in the braking pressure calculation map, as shown in FIG. 4, the horizontal axis represents the target acceleration / deceleration G ^*, and the vertical axis represents the target braking pressure P.
Take _B ^*, the target braking pressure P in until a and negative when the target acceleration G ^* is positive exceeds a predetermined value -G _S
B ^* maintains “0”, and the target acceleration / deceleration G ^* is a predetermined value−G
_{When the} speed exceeds _S, the target braking pressure P _B ^* is set to increase linearly in proportion to the increase in the negative direction of the target acceleration / deceleration G ^* .

Since FIG. 4 can be expressed by a mathematical expression, the arithmetic operation may be performed by the mathematical expression without using a memory map. Then, the processing proceeds to step S8c, the vehicle speed V (n) is carried out the calculation of the original in the following (4) equation, to calculate the pressurization command value P _ST.

P _ST = αV + P ₀ (4) where α is a constant, and P ₀ is the minimum braking pressure required to keep the vehicle stopped.

Next, the routine proceeds to step S8d, where it is determined whether or not the inter-vehicle distance D (n) exceeds the safely stopped inter-vehicle distance D _ST (n). The safety stop inter-vehicle distance _DST is calculated as follows.

That is, assuming that the conversion gain for converting the deceleration into the braking pressure is K _P , the deceleration G (t) is G (t) = (αV (t) + P ₀ ) / K _P (...) 5)

The own vehicle speed V is the vehicle speed at the start of decompression.
Assuming ₀ , V (t) = ∫G (t) dt = Ｖ (αV (t) + P ₀ ) / K _P ｝ dt (6) V (0) = V ₀ . The time T required to stop is a solution T of the equation V (t) = ∫ ｛(αV (t) + P ₀ ) / K _P ｝ dt = 0 (7) for t. By integrating V, the inter-vehicle distance D _ST required to stop is as follows.

[0041]

(Equation 1)

Then, the determination result of step S8d is D ≦
When a D _ST, when the current vehicle distance D is transition to the safe inter-vehicle distance D _ST shorter than direct braking pressure is determined that unfavorable under reduced pressure to step S8f, a D> D _ST is present inter-vehicle distance D has exceeded the safe inter-vehicle distance D _ST, the process proceeds to step S8e it is determined that the possible decompression braking pressure.

In step S8e, the target braking pressure P _B
^* Is equal to or less than the reduced pressure command value P _ST, P _B ^*
If <P _ST , it is determined that a braking pressure based on the following distance is necessary, and the flow shifts to step S8f to set a braking pressure P ^*.
Step S8h after setting the target braking pressure P _B ^* as
When P _B ^* ≧ P _ST , it is determined that pressure reduction control is necessary immediately before stopping, and the flow shifts to step S8g, where a pressure reduction command value P _ST is set as the braking pressure P ^*. Then, control goes to a step S8h.

In step S8h, the actual braking pressure P is read, and then the process proceeds to step S8i, in which a braking pressure feedback control process is performed so that the actual braking pressure matches the braking pressure P ^*. And returns to step S1 in FIG.

In the process shown in FIG.
The processing in S8 corresponds to the travel control means, and in the processing in FIG. 3, the processing in steps S8c to S8e and S8g corresponds to the deceleration correction means.

Therefore, as shown in FIG. 5, at time t ₁ , the preceding vehicle is, for example, the target vehicle speed V ^* set by the own vehicle ^.
Assuming that the vehicle is traveling at a substantially constant speed at a lower vehicle speed, in this state, if the actual inter-vehicle distance D becomes longer than the target inter-vehicle distance D ^* (n) calculated in step S3 in the process of FIG. When it is determined that the inter-vehicle distance is too large, the process proceeds to step S5, and a positive target acceleration / deceleration G ^* corresponding to a deviation between the set vehicle speed V ^* and the host vehicle speed V (n) is calculated.

Therefore, in the engine control process of step S7, a positive throttle opening change amount Δθ corresponding to the positive target acceleration / deceleration G ^* is calculated, and this is added to the current throttle opening command value θ to obtain a new value. The throttle opening command value θ is calculated, and the throttle opening command value θ is increased.
Is controlled to increase, and the vehicle speed V at that time is controlled.
(n) and the throttle opening command value θ, a shift position command value TS is set, and the transmission control device 10 controls the shift position of the automatic transmission 3 to be controlled to an acceleration state, and the inter-vehicle distance D Becomes shorter.

On the other hand, in the braking control process in step S8, since the target acceleration / deceleration G ^* is positive, the target braking pressure P _B ^* calculated in step S8b becomes “0”. The braking pressure is set to "0" and the braking is controlled to a non-braking state in which no braking force is generated.

[0049] Conversely, when the inter-vehicle distance D becomes the target inter-vehicle distance D ^* below, the process proceeds to step S6, but a negative target acceleration G ^* is calculated, the target acceleration G ^* is a predetermined value when not exceed -G _S, by negative throttle opening change amount Δθ is calculated, decreased throttle opening command value θ is, but whereby the engine output is reduced, the braking control process, the target Since the braking pressure P _B ^* maintains “0”, the non-braking state is continued, and the braking control is performed only by the decrease in the engine output.

If the inter-vehicle distance D becomes shorter even when the braking control is performed only by decreasing the engine output, the target acceleration / deceleration G ^* calculated in step S6 further increases in the negative direction to reach the predetermined value -G _S , the throttle opening command value θ is set to “0” in the engine control process of step S7, and the target braking pressure P _B ^* calculated in step S8b in the braking control process ^.
Increases in the forward direction, the braking pressure of the disc brake 7 is increased to generate a braking force, and the own vehicle is in a deceleration state, and the inter-vehicle distance D is increased.

From this state, when the vehicle shifts to a deceleration state in which the preceding vehicle stops at time t ₂ and the deceleration becomes relatively large, the inter-vehicle distance D is shortened accordingly. Braking control is started.

[0052] At this time, ^* the target braking pressure P _B calculated in step S8b, the preceding vehicle between time t ₂ ~t ₃ is allowed to gradually increase the deceleration preceding the vehicle between subsequent time t ₃ ~t ₄ because There is decelerated at a constant deceleration, braking pressure of the vehicle is maintained at a constant pressure, but as a broken line shown reduced pressure command value P _ST calculated at step S8c in FIG. 5 (b), at the start of braking the own Since the vehicle speed V (n) is high, the target braking pressure P _B ^*
It is a very high value compared to.

In a normal braking state other than a sudden braking state such as an emergency stop, the inter-vehicle distance D is a safe stop inter-vehicle distance D.
_{Since ST} does not exceed _ST , the process proceeds from step S8d to step S8e. Since P _B ^* <P _ST as described above, the process proceeds to step S8f, where the target braking pressure P _B ^* is set as the braking pressure P ^*. As a result, the braking pressure of the disc brake 7 is increased according to the target braking pressure P _B ^* as shown in FIG. 5B, and the own vehicle speed V (n) is correspondingly increased as shown in FIG. ), The deceleration control state is rapidly reduced.

Then, this deceleration control state is continued,
Become a vehicle speed just before stopping, when the reduced pressure command value P _ST calculated at time t ₄ at step S8c is equal to or less than the target braking pressure P _B ^* calculated at step S8b, the process proceeds from step S8e to step S8g, The pressure reduction command value P _ST is equal to the braking pressure P
Set as ^* .

Therefore, thereafter, the braking pressure of the disc brake 7 is controlled in accordance with the pressure reduction command value _PST ,
As shown in FIG. 5B, the braking pressure decreases at a constant gradient,
In response, as shown in FIG. 5 (a), the decrease amount of the vehicle speed V (n) decreases, and the vehicle enters a slow deceleration state.

[0056] After that, at the time t ₅ vehicle speed V (n) is "0"
, The pressure reduction command value P _ST calculated in step S8c
There will only pressure P ₀ required for maintaining the stopped state, it is possible to continue the stop state.

As described above, immediately before the stop, the vehicle shifts from the rapid deceleration state to the slow deceleration state, so that the nose dive phenomenon at the time of stopping the vehicle can be suppressed. A change can be reliably prevented, and a good ride quality can be secured.

Further, since the slow deceleration state is controlled using the pressure reduction command value _PST calculated based on the equation (4) which is a function of the own vehicle speed V (n), the own vehicle speed V (n) is controlled. As the value of n) decreases, the deceleration also decreases, and the nose dive phenomenon when the vehicle stops can be reliably prevented, and the riding comfort can be further improved.

When the preceding vehicle starts running again from this stopped state, the inter-vehicle distance D is correspondingly increased, and the target inter-vehicle distance D ^* when the vehicle is stopped is D _0.
D ^* , the process proceeds from step S4 to step S5, and a positive target acceleration / deceleration G ^* is calculated. In response, the throttle opening change amount Δθ becomes positive in the engine control process, and the throttle opening command value θ becomes As well as a large value
By setting the target braking pressure P _B ^* in the braking control process to “0” and setting this as the braking pressure P ^* ,
The braking pressure of the disc brake 7 becomes "0", the vehicle is accelerated in the non-braking state, and the following traveling control for following the preceding vehicle is resumed.

On the other hand, when the preceding vehicle is
When the vehicle shifts, the inter-vehicle distance D decreases gradually.
Thus, the target braking pressure calculated in step S8b
P_B ^*Is also small, and this target braking pressure P_B ^*Is decompressed
Command value P_STIf it is less than the target braking pressure P_B ^*I
Will be in the stopped state.

When the preceding vehicle performs sudden braking such as an emergency stop and the inter-vehicle distance D is sharply reduced, and the inter-vehicle distance D becomes smaller than the safe stop inter-vehicle distance D _ST , the process proceeds directly from step S8d. The process proceeds to S8f, where the target braking pressure P _B ^* is set as the braking pressure P ^*. Therefore, the rapid deceleration state in which the target inter-vehicle distance D ^* is maintained can be maintained without shifting to the slow deceleration state. Reliable stop control can be performed.

Further, since the safe stop inter-vehicle distance D _ST is calculated based on the equation (8) as the inter-vehicle distance required for stopping by integrating the own vehicle speed, it is accurately determined whether or not to shift to the slow deceleration state due to the pressure reduction. Can be determined.

[0063] In the above embodiment, it calculates the target inter-vehicle distance D ^*, by comparing the actual inter-vehicle distance D between the target inter-vehicle distance D ^*, the case of calculating the target deceleration G ^* Description However, the present invention is not limited to this, and the time (inter-vehicle time) T until the host vehicle reaches L ₀ (m) behind the preceding vehicle based on the inter-vehicle distance D (n).
_A target vehicle speed V ^* (n) is determined so that ₀ becomes constant, and an engine output command value α is calculated based on a deviation ΔV (n) between the target vehicle speed V ^* (n) and the actual vehicle speed V (n). In some cases, the engine is controlled based on the calculated engine output command value α to be in an accelerating state, and when negative, the speed deviation ΔV (n)
May be set by PD control or PID control on the basis of the target braking pressure.

In the above embodiment, the case where the pressure reduction command value P _ST is calculated based on the equation (4) has been described. However, the present invention is not limited to this, and the control map corresponding to the equation (4) is used. May be stored in a memory in advance, and the pressure reduction command value _PST may be calculated with reference to this control map. Further, the present invention is not limited to the case where the pressure reduction command value _PST is continuously changed. The equation (4) further describes the case where the vehicle speed is a linear function. However, the present invention is not limited to this, and the vehicle speed may be a quadratic function. It is only necessary that the deceleration can be reduced.

Further, in each of the above embodiments,
The case where the P-control is used for the vehicle speed feedback formula of the formula (2) and the inter-vehicle distance feedback formula of the formula (3) has been described. However, the present invention is not limited to this.
It goes without saying that D control may be applied.

Further, in each of the above embodiments,
Although the case where the own vehicle speed V (n) is calculated by the average value of the wheel speeds of the driven wheels has been described, the present invention is not limited to this.
It is also possible to calculate the vehicle speed by detecting the number of revolutions on the output side of the automatic transmission 3 or to apply a vehicle speed calculating means used in the antilock brake control device.

Furthermore, in the above embodiment, the case where the automatic transmission 3 is provided on the output side of the engine 2 has been described. However, the present invention is not limited to this, and a continuously variable transmission can be applied. .

In the above embodiment, the case where the present invention is applied to a rear wheel drive vehicle has been described. However, the present invention can be applied to a front wheel drive vehicle or a four wheel drive vehicle. Instead, the present invention can be applied to an electric vehicle to which an electric motor is applied, or a hybrid vehicle using both the engine 2 and the electric motor. In this case, an electric motor control device may be applied instead of the engine output control device.

[Brief description of the drawings]

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

FIG. 2 is a flowchart illustrating an example of a travel control processing procedure of a travel control controller.

FIG. 3 is a flowchart illustrating a specific example of a braking control process in the traveling control process of FIG. 2;

FIG. 4 is an explanatory diagram showing an example of a target braking pressure calculation map showing a relationship between a target acceleration / deceleration and a target braking pressure.

FIG. 5 is a time chart for explaining the operation of the embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1FL, 1FR Front wheel 1RL, 1RR Rear wheel 2 Engine 3 Automatic transmission 7 Disc brake device 8 Brake control device 9 Engine output control device 10 Transmission control device 12 Distance between vehicles 13L, 13R Wheel speed sensor 20 Controller for traveling control

Claims (4)

[Claims] An inter-vehicle distance detecting means for detecting an inter-vehicle distance from a preceding vehicle, wherein the inter-vehicle traveling control device performs speed control for following the preceding vehicle while maintaining the inter-vehicle distance to the preceding vehicle at a predetermined value. A travel control means for calculating a target acceleration / deceleration based on the inter-vehicle distance detected by the inter-vehicle distance detection means and the target inter-vehicle distance, and performing a follow-up traveling control according to the calculated target acceleration / deceleration; A deceleration correcting means for correcting the deceleration set by the travel control means to a slow deceleration when the vehicle speed near the stop is reached while the deceleration control based on the target deceleration is continued. Traveling control device for vehicles. 2. The travel control means calculates a target braking pressure corresponding to the target deceleration when the target deceleration is calculated, and controls a braking pressure of a braking cylinder according to the target braking pressure. The deceleration correcting means is configured to correct the target braking pressure to the pressure reducing command value when the pressure reducing command value calculated as a function of the vehicle speed becomes equal to or less than the target braking pressure. The travel control device for a vehicle according to claim 1, wherein: 3. The deceleration correcting means is configured to change to a slow deceleration when the inter-vehicle distance detected by the inter-vehicle distance detecting means is equal to or longer than a safe stop inter-vehicle distance. The vehicle travel control device according to claim 1 or 2. 4. The safe inter-vehicle distance is obtained by integrating the deceleration obtained by dividing the sum of the own vehicle speed multiplied by the rate of change in depressurization and the stop maintaining braking pressure by the deceleration / brake pressure conversion gain. The travel control device for a vehicle according to claim 3, wherein the calculation is performed by integrating the time required for stopping the vehicle.