JPH11278097A - Running control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain delay of deceleration timing of an own vehicle to prevent a sense of incongruity when a preceding vehicle is transferred to a deceleration state, by setting and maintaining inter-vehicle distance between it and the detected preceding vehicle to a target inter vehicle distance, and by providing a correcting means for limiting own vehicle's acceleration to the estimated or detected acceleration of the preceding vehicle. SOLUTION: A controller 20 for running control, by controlling a brake/ control device 8, an engine power control device 9, a transmission control device 10, based on inter-vehicle distance L detected by an inter-vehicle distance sensor 12, wheel speeds VwL, VwR detected by wheel speed sensors 13L, 13R, and output signals of a front and back acceleration sensor 14, performs following- running control for following-running a car with maintaining an adequate inter- vehicle distance between it and a preceding vehicle. In addition, when the preceding vehicle goes into an acceleration state during the following-running control, by setting the detected or estimated acceleration of the proceeding vehicle as an acceleration upper limit of an own vehicle, generation of unnecessary acceleration state when the proceeding vehicle goes into an deceleration state is certainly prevented.

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 performs speed control for following a preceding vehicle while maintaining a distance between the vehicle and the preceding vehicle.

[0002]

2. Description of the Related Art A conventional traveling control device for a vehicle is disclosed, for example, in JP-A-61-77533.

In this conventional example, a distance difference between an inter-vehicle distance detected by an inter-vehicle distance detecting means and a safe inter-vehicle distance based on a vehicle speed is calculated, and a time change of the calculated distance difference is calculated. There is described an inter-vehicle distance control device in which a traveling speed is controlled by a vehicle speed control means so that the inter-vehicle distance becomes a safe inter-vehicle distance based on the change and the traveling speed.

[0004]

However, in the above-mentioned conventional inter-vehicle distance control device, the following traveling control is performed while maintaining the safe inter-vehicle distance with the preceding vehicle, but the preceding vehicle continues to accelerate. There is an unsolved problem that the deceleration timing of the host vehicle may be delayed when the vehicle shifts to the deceleration state.

That is, the preceding vehicle continues to accelerate as shown by the broken line in FIG.
In FIG. 8A, the acceleration state is continued as shown by the solid line, but the inter-vehicle distance between the preceding vehicle and the host vehicle gradually increases from the target inter-vehicle distance D ^{* as} shown in FIG. 8B. At time t ₁ , when the preceding vehicle turns from the acceleration state to the deceleration state as shown by the broken line in FIG.
Since the inter-vehicle distance at this time is larger than the target inter-vehicle distance D ^* , the own vehicle continues the acceleration state as shown by the solid line in FIG.

[0006] Then, at time t ₂ the inter-vehicle distance is lower than the target inter-vehicle distance D ^*, so that the vehicle shifts to the first speed reduction state. Therefore, even though the preceding vehicle has shifted to the deceleration state, the vehicle continues to accelerate until the inter-vehicle distance becomes equal to or less than the target inter-vehicle distance D ^*. As a result, the distance between the vehicles becomes shorter than the distance D ^* , which gives the driver an uncomfortable feeling.

Therefore, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and suppresses the delay of the deceleration timing of the own vehicle when the preceding vehicle shifts from the acceleration state to the deceleration state. It is an object of the present invention to provide a vehicular travel control device capable of reliably preventing a driver from feeling uncomfortable.

[0008]

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 configured as described above, an inter-vehicle distance detecting unit that detects an inter-vehicle distance from a preceding vehicle and a target acceleration / deceleration are set such that the inter-vehicle distance detected by the inter-vehicle distance detecting unit matches the target inter-vehicle distance. Target acceleration / deceleration setting means, traveling control means for controlling traveling to maintain the target acceleration / deceleration set by the target acceleration / deceleration setting means,
When the target acceleration is set by the target acceleration / deceleration setting means, the target acceleration is estimated or detected. The acceleration correction means limits the acceleration to the acceleration of the preceding vehicle.

According to the first aspect of the present invention, when the preceding vehicle is accelerated, the acceleration of the host vehicle is limited to the acceleration of the preceding vehicle. When the vehicle shifts, the acceleration becomes zero, whereby the acceleration of the host vehicle is limited to zero and the vehicle enters the constant-speed running state, thereby avoiding unnecessary acceleration.

According to a second aspect of the present invention, in the vehicle traveling control device according to the first aspect, the acceleration correction means detects or estimates the acceleration of the preceding vehicle, and the preceding vehicle acceleration calculating means. Acceleration upper limit value setting means for setting the preceding vehicle acceleration detected or estimated by the acceleration calculation means as an acceleration upper limit value; and setting the target acceleration to the acceleration upper limit when the target acceleration set by the target acceleration setting means exceeds the acceleration upper limit value. Acceleration limiting means for limiting to a value.

According to the second aspect of the present invention, the preceding vehicle acceleration calculating means detects or estimates the acceleration of the preceding vehicle and sets the acceleration of the preceding vehicle as the acceleration upper limit value. In some cases, the acceleration of the preceding vehicle is set as an acceleration upper limit value, and when the preceding vehicle is in a constant speed running state or a decelerating state, the acceleration of the preceding vehicle becomes "0". When the vehicle enters the state or the deceleration state, even if the target acceleration is set, the own vehicle maintains the constant speed traveling state by being limited to “0”.

Further, in the vehicle traveling control apparatus according to a third aspect, in the invention according to the second aspect, the acceleration upper limit value setting means determines whether or not the preceding vehicle is in an accelerated state, and determines whether the preceding vehicle is in an accelerated state. When this happens, the acceleration of the preceding vehicle is set instead of the normal set value as the acceleration upper limit value, and when the constant speed running state continues for the set time or more during this time, the acceleration is returned to the normal set value. It is characterized by:

According to the third aspect of the present invention, since the acceleration of the host vehicle is limited to the acceleration of the preceding vehicle, the speed of the host vehicle is always lower than the speed of the preceding vehicle. When the vehicle shifts to the constant speed running state, the acceleration upper limit value of the vehicle speed is “0”.
The vehicle will travel at a constant speed, and the inter-vehicle distance will continue to increase due to the speed difference from the preceding vehicle.However, by returning the upper acceleration limit to the normal value after a predetermined time has elapsed, acceleration is permitted and Match the distance to the target inter-vehicle distance.

Further, in the vehicle traveling control apparatus according to a fourth aspect, in the invention according to the third aspect, the acceleration upper limit value setting means gradually returns the acceleration upper limit value to a normal setting value. Features.

In the invention according to claim 4, when returning to the normal set value from the state where the acceleration upper limit value is set to zero, the acceleration upper limit value gradually changes to the normal set value, Prevent sudden changes in acceleration.

Further, according to a fifth aspect of the present invention, in the vehicle travel control apparatus according to the second aspect, the acceleration upper limit value setting means determines whether or not the preceding vehicle has been accelerated, and When the preceding vehicle acceleration is set instead of the normal set value as the acceleration upper limit value, and when the set state continues for the set time or more and the preceding vehicle acceleration becomes less than the normal set value, the acceleration It is characterized in that it is configured to return the upper limit value to the normal set value.

In the invention according to the fifth aspect, when the acceleration state of the preceding vehicle continues for a long time, it is determined that the vehicle will shift to the constant speed thereafter, and the acceleration upper limit is normally set from the acceleration of the preceding vehicle. At this time, when the preceding vehicle acceleration falls below the normal set value, the vehicle is returned to the normal set value, thereby preventing a large change in the acceleration upper limit value.

[0018]

According to the first aspect of the present invention, the deceleration of the preceding vehicle increases when the preceding vehicle shifts from the acceleration state to the deceleration state during the follow-up control for following the preceding vehicle. Since the acceleration becomes zero, the host vehicle is switched from the acceleration state to the constant speed traveling state by setting the preceding vehicle acceleration as the acceleration upper limit value. Therefore, it is possible to reliably prevent a delay in deceleration timing and a driver's uncomfortable feeling that the host vehicle is accelerating while the preceding vehicle is decelerating.

According to the second aspect of the present invention, when the preceding vehicle is in an accelerating state, the preceding vehicle acceleration is set as an acceleration upper limit value, and when the preceding vehicle is in a constant speed running state or a decelerating state, Vehicle acceleration is "0"
Accordingly, when the preceding vehicle changes from the acceleration state to the constant speed traveling state or the deceleration state, even if the target acceleration is set, the own vehicle is limited to “0”, and thereby the constant speed traveling state is set. It is possible to obtain an effect that the unnecessary acceleration state when the preceding vehicle is decelerated can be reliably prevented from being maintained.

Further, according to the third aspect of the invention, the acceleration of the host vehicle is limited to the acceleration of the preceding vehicle, so that the speed of the host vehicle is always lower than the speed of the preceding vehicle. When the vehicle shifts from the acceleration state to the constant speed traveling state, the acceleration upper limit value of the own vehicle speed is “0”.
The vehicle will travel at a constant speed, and the inter-vehicle distance will continue to increase due to the speed difference from the preceding vehicle.However, by returning the upper acceleration limit to the normal value after a predetermined time has elapsed, acceleration is permitted and The effect is obtained that the distance can be made to match the target inter-vehicle distance.

Further, according to the invention of claim 4, in the invention of claim 3, when the acceleration upper limit value is returned to the normal set value, the change is made gradually, so that a sudden change in acceleration can be prevented. As a result, the effect that running stability can be ensured can be obtained.

According to the fifth aspect of the present invention, when the acceleration state of the preceding vehicle continues for a long time, it is determined that the vehicle shifts to constant-speed running, and the acceleration upper limit value is set to the preceding vehicle acceleration. However, by returning to the normal set value when the preceding vehicle acceleration falls below the normal set value at this time, a large change in the acceleration upper limit value can be prevented, and the driver feels discomfort. An effect is obtained that good follow-up running control can be performed without giving.

[0023]

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

Front wheels 1FL, 1FR and rear wheels 1RL, 1R
R 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 is configured to generate a braking oil pressure in accordance with a depression of a brake pedal (not shown) and to generate a braking oil pressure in accordance with a braking pressure command value from the traveling control controller 20. Have been.

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 from a preceding vehicle is provided below the vehicle body on the front side of the vehicle.

The vehicle is provided with wheel speed sensors 13L and 13R for detecting the wheel speeds of the front wheels 1FL and 1FR, and a longitudinal acceleration sensor 14 for detecting the longitudinal acceleration Gm of the vehicle. Have been.

The output signals of the inter-vehicle distance sensor 12, the wheel speed sensors 13L and 13R, and the longitudinal acceleration sensor 14 are input to the traveling control controller 20, and the traveling control controller 20 causes the inter-vehicle distance sensor 1 to operate.
, The wheel speed sensors 13L, 13
Wheel speed Vw L detected by the _R, based on the Vw _R, brake controller 8, by controlling the engine output controller 9 and the transmission controller 10 to maintain the proper vehicle distance between the preceding vehicle When the preceding vehicle shifts to an accelerated state during the following traveling control, the preceding vehicle decelerates by setting the detected or estimated preceding vehicle acceleration as the acceleration upper limit value of the own vehicle. Unnecessarily accelerating state is prevented from occurring when shifting to the state.

Next, the operation of the first embodiment will be described with the traveling control processing shown in FIG. 2 executed by the traveling control controller 20. This traveling control process is performed for a predetermined time (for example, 10 msec) for a predetermined main program.
This is executed as a timer interrupt process for each
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, and the following vehicle speed V (n) and the time T ₀ (inter-vehicle time) required for the vehicle to reach the position L ₀ [m] behind the current preceding vehicle are as follows. 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) By adopting the concept of inter-vehicle time, the inter-vehicle distance is set to increase as the vehicle speed increases. . Incidentally, D ₀ is stopped when the inter-vehicle distance.

Next, the process proceeds to step S4, where it is determined 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.

[0035] _{^{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.

[0036] _{^{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
^The acceleration limiting process described below for limiting ^* is performed.

Then, the process proceeds to step S8, in which the throttle opening command value θ for the engine control device 9 and the up / down shift command value T for the transmission control device 10 are set.
After calculating S and executing an engine control process for outputting these, the process proceeds to step S9.

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 S9, the target braking pressure P is determined based on the target acceleration / deceleration G ^* stored in the acceleration / deceleration storage area.
_B ^* is calculated, and a brake pressure control process for outputting the calculated _B ^* to the brake control device 8 is performed. Then, the timer interrupt process is terminated, and the process returns to the predetermined main program.

[0041] Here, the target braking pressure P _B ^* is the target deceleration G ^* with reference to the braking pressure calculation map shown in FIG. 4 which has previously been stored in the memory on the basis of calculating the target braking pressure P _B ^* .
Map out the braking pressure calculation, as shown in FIG. 4, the target acceleration G ^* the horizontal axis and the vertical axis to the target braking pressure P _B ^*, a and negative when the target acceleration G ^* is positive Predetermined value -G
Maintaining the target braking pressure P _B ^* "0" is until exceeds _S, the target acceleration G ^* exceeds a predetermined value or more -G _S, proportional to the increase in the negative direction of the target acceleration G ^* Thus, the target braking pressure P _B ^* is set to increase linearly.

Then, as shown in FIG. 3, a specific example of the above-described acceleration limiting processing in step S7 is performed first in step S7.
At 11, the longitudinal acceleration Gm (n) of the longitudinal acceleration sensor 14 is read, and then the process proceeds to step S12 to estimate the current acceleration Gt (n) of the preceding vehicle.

The acceleration Gt (n) of the preceding vehicle is calculated by differentiating the inter-vehicle distance D detected by the inter-vehicle distance sensor 12 by the second order, as represented by the following equation (4). Is calculated by adding the longitudinal acceleration Gm (n) of the host vehicle detected by the longitudinal acceleration sensor 14 to the relative acceleration, and the estimated relative acceleration is stored in the current preceding vehicle acceleration storage area formed in the storage device. The stored previous preceding vehicle acceleration Gt (n-1) is stored in the previous preceding vehicle acceleration storage area, and the estimated current preceding vehicle acceleration Gt (n) is stored in the current preceding acceleration storage area.

Gt (n) = d ² D / dt ² + Gm (n) (4) Then, the process proceeds to step S 13, where the calculated current preceding vehicle acceleration Gt (n) is positive, ie, the preceding vehicle Is determined to be in an accelerating state, and if Gt (n)> 0, it is determined that the preceding vehicle is in an accelerating state, and the routine goes to step S14.

In step S14, the acceleration upper limit G
_The current preceding vehicle acceleration Gt (n) is set as _UP , and then the process proceeds to step S15, where the traveling state flag F indicating the constant speed traveling state is set to indicate that the state other than the constant speed traveling state is continued. After resetting to "0", the process proceeds to step S16.

[0046] In the step S16, it reads out the target acceleration G ^* which is stored is calculated in step S5 or S6 in FIG. 2 described above to the target acceleration speed storage area, the target acceleration G ^* is the acceleration upper limit value It is determined whether or not it is G _UP or more. If G ^* ≧ G _UP , the target acceleration / deceleration G ^* is limited to the acceleration upper limit G _UP , and this is updated and stored in the target acceleration / deceleration storage area, and then the acceleration is limited. After terminating the process, the process proceeds to step S8 in FIG. 2 and G ^* <G _UP
In the case of, the acceleration limiting process is terminated as it is and FIG.
The process moves to step S8.

On the other hand, if the result of the determination in step S13 is G
If t (n) ≦ 0, it is determined that the preceding vehicle is in a decelerating state other than the accelerating state or in a constant speed running state, and step S
18 and the current vehicle speed V (n) becomes the previous vehicle speed V (n).
(n-1) is determined, and if they do not match, it is determined that the vehicle is not decelerating but running at a constant speed.
_UP is set to "0", and then the process proceeds to step S20, where the running state flag F is reset to "0", and then to step S16. And the process moves to step S21.

In this step S21, it is determined whether or not the running state flag F is set to "1". When the running state flag F is set to "1", the process directly jumps to step S23 to be described later, and returns to "0". If reset, the process proceeds to step S22, in which the traveling state flag F is set to "1", and the count value T of the timer for measuring the duration of the constant speed traveling state is cleared to "0". Move to

In this step S23, it is determined whether or not the count value T of the timer has become equal to or greater than a preset value T _SET . If T <T _SET, it is determined in step S24.
Then, the count value T of the timer is incremented by "1", and then the process proceeds to step S16, where T ≧ T
_If it is a _SET , the process moves to step S25.

In step S25, the acceleration upper limit G _UP stored in the acceleration upper limit storage area is set to a preset normal setting value (default value, for example, 0.03 to 0.03).
About 0.06G) It is determined whether it is less than G _DEF ,
_UP <When a G _DEF, the process proceeds to step S26, and proceeds after setting a value obtained by adding a predetermined value ΔG in the current upper limit of acceleration G _UP as a new upper limit of acceleration G _UP to the step S16, If G _UP ≧ G _DEF , the process proceeds to step S27 to set the normal set value G _DEF as the acceleration upper limit G _UP , and then _proceeds to step S28 to reset the traveling state flag F to “0”. Then, control goes to the step S16.

In the process shown in FIG.
The processing of S6, S8 and S9 corresponds to the traveling control means, the processing of step S7 corresponds to the acceleration correction means, and in the processing of FIG. 3, the processing of steps S11 and S12 corresponds to the preceding vehicle acceleration / deceleration calculation means, Steps S13 to S15
The processing of S18 to S28 corresponds to the acceleration upper limit value setting means, and the processing of steps S16 and S17 corresponds to the acceleration limiting means.

[0052] Thus, now, as shown in FIG. 5, the time t _0, for example, traffic is assumed that the preceding vehicle and the subject vehicle at a red light is stopped in a relatively short inter-vehicle distance distance. In this stopped state, the vehicle speed V calculated in step S2 of FIG.
(n) is because it is "0", ^* target inter-vehicle distance D calculated in step S3 is to maintain the state of the predetermined value D _0.

[0053] When the traffic at time t ₁ from the stop state preceding vehicle by a green light is shifted to slow start to the accelerating state as indicated by the broken line shown in FIG. 5 (a), FIG. 5 (c accordingly ) inter-vehicle distance D increases as indicated, the inter-vehicle distance D is larger than the target inter-vehicle distance D ^* (= 0) at time t _1, the process proceeds from step S4 to step S5, ^* an own set vehicle speed V After calculating a positive value of the target acceleration / deceleration G ^* representing the acceleration based on the deviation from the vehicle speed V (n), step S
Then, the process proceeds to step S7, where the acceleration limiting process is executed.

[0054] In the acceleration limit process, as shown in FIG. 3, the vehicle of the read longitudinal acceleration Gm Muga in step S11, since this in the time t ₁ the vehicle is still in the stop state, the longitudinal acceleration Gm is " 0 ", and the step S
The preceding vehicle acceleration / deceleration Gt (n) estimated at 12 is a positive value because the preceding vehicle starts and the inter-vehicle distance increases.

Therefore, the preceding vehicle acceleration / deceleration Gt (n) is set as the acceleration upper limit G _UP (step S14), and then the running state flag F is reset to "0" (step S15).

At this time, the preceding vehicle is in a slow start state,
Since the preceding vehicle deceleration Gt (n) is small, also becomes smaller upper limit of acceleration G _UP, step S17 when the above-mentioned target acceleration calculated in step S5 in FIG. 2 G ^* is equal to or greater than the acceleration upper limit value G _UP Then, the target acceleration / deceleration G ^* is limited to the acceleration upper limit G _UP , and the target acceleration G ^* that follows the acceleration state of the preceding vehicle is set.

For this reason, in step S7 of FIG. 2, the throttle opening θ and the shift position ST according to the set target acceleration G ^* are set, and these are set to the engine output control device 9.
5 is supplied to the transmission control device 10, so that the host vehicle starts at an acceleration corresponding to the target acceleration G ^* as shown by the solid line in FIG.

Thereafter, at time t_TwoThe leading vehicle is shown in FIG.
As shown in FIG. _DEFSmaller value
When the vehicle shifts to the constant acceleration state to maintain,
As shown in FIG. 5C, the separation D is the target headway indicated by the dashed line.
Distance D^*It will change in the direction of longer, but before
As described above, the target acceleration / deceleration G^*Is the normal set value G_DEFThan
Because the vehicle acceleration / deceleration Gt (n) is limited to a small value,
The vehicle follows while the distance becomes gradually longer.

Thereafter, at time t ₃ , the preceding vehicle moves to the state shown in FIG.
When the vehicle shifts from the acceleration state to the deceleration state as shown by the broken line in FIG. 5, the preceding vehicle acceleration / deceleration Gt (n) at this time becomes
As shown in (b), it becomes "0".

For this reason, when the acceleration limiting process of FIG. 3 is executed, the process proceeds from step S13 to step S18,
Since the current vehicle speed V (n) is higher than the previous value V (n-1) since the vehicle has been accelerated, the process proceeds from step S18 to step S19, and the acceleration upper limit G _UP is set to “0”.
Then, the process proceeds to step S20 to continue the state in which the traveling state flag F is reset to “0”, and then proceeds to step S16.

Therefore, the inter-vehicle distance D is considerably larger than the target inter-vehicle distance D ^* as shown in FIG. 5C, and the target acceleration / deceleration G ^* calculated in step S5 in FIG. Since this is limited to the acceleration upper limit G _UP of “0”, the vehicle speed V (n) of the own vehicle becomes a constant value as shown by the solid line in FIG. Transition to the state.

At this time, the preceding vehicle is in a deceleration state,
The vehicle speed is the vehicle speed V of the own vehicle as shown by the broken line in FIG.
(n), the inter-vehicle distance D continues to increase as shown by the solid line in FIG.

When the vehicle shifts to the constant speed running state, the preceding vehicle continues to be in the deceleration state when the processing of FIG. 3 is executed next.
8, since the vehicle is in the constant-speed running state, the flow proceeds to step S21, and since the running state flag F has been reset to "0", the flow proceeds to step S22, where the running state flag F is set to "1". , And the count value T of the timer for counting the duration of the constant-speed running state is cleared to "0", and the routine goes to Step S23.

At this time, the count value T of the timer is
Since it is “0”, the set value T_SETLess than, step
The process proceeds to S24, where the count value T is incremented.
From step S16 to target acceleration / deceleration G^*To
Acceleration upper limit G set to “0” _UPState restricted to
continue.

Thereafter, every time the processing of FIG. 3 is executed, the count value T of the timer is sequentially incremented and increased. When the vehicle speed of the vehicle speed and the vehicle of the preceding vehicle at time t ₄ are equal, stops increasing the inter-vehicle distance D, then Figure 5 vehicle speed Vt of the preceding vehicle as shown in (a) (n) of the vehicle When the vehicle speed falls below V (n), the following distance D
However, as shown by the solid line in FIG. 5 (c), it first contracts gradually, but it contracts rapidly as the speed difference between the preceding vehicle and the host vehicle increases.

Thereafter, when the inter-vehicle distance D becomes equal to the target inter-vehicle distance D ^* at time t ₅ , the process shifts from step S4 to step S6 in FIG. 2, and is performed according to the deviation between the inter-vehicle distance D and the target inter-vehicle distance D ^*. The calculated target acceleration / deceleration G ^* is calculated. At this time, since the inter-vehicle distance D is equal to the target inter-vehicle distance D ^* , the first term on the right side in the above equation (3) is "0", but the target acceleration / deceleration G ^{* is obtained} by the second term on the right side.
Is a negative value representing the deceleration.

For this reason, by performing the braking force control according to the target acceleration / deceleration G ^* in the braking control process of step S9 in FIG. 2, the braking force is generated by the disc brake 7, and the own vehicle is moved to the state shown in FIG. The state shifts to the deceleration state as shown in ()).

When the host vehicle is decelerated, the target inter-vehicle distance D ^* also decreases as shown by the dashed line in FIG. 5C, and the target acceleration / deceleration G ^* becomes as shown in the above equation (3). The difference between the inter-vehicle distance D and the target inter-vehicle distance D ^*
5C, the inter-vehicle distance D detected by the inter-vehicle distance sensor 12 decreases while falling below the target inter-vehicle distance D ^* as shown by the solid line in FIG. 5C.

Since the current vehicle speed V (n) becomes smaller than the previous value V (n-1) by the deceleration state of the own vehicle, it is determined that the constant speed running state has been completed. When it is determined, the process proceeds from step S19 to step S20, and the traveling state flag F is reset to "0".

Therefore, when the vehicle returns to the constant-speed running state again, the process proceeds from step S19 to step S22 via step S21, and the count value T of the timer is cleared to "0". With the count value T, the continuation time of the constant-speed running state can be accurately measured.

Thereafter, when the preceding vehicle stops at time t ₆ , the preceding vehicle acceleration / deceleration Gt (n) also becomes “0”, and then the own vehicle stops at time t ₇ . As described above, when the preceding vehicle shifts from the acceleration state to the deceleration state, the own vehicle sets the acceleration upper limit G _UP to the acceleration of the preceding vehicle, that is, “0”. As a result, an unnecessary acceleration state is not continued as in the conventional example described above, and it is possible to reliably prevent the driver from feeling uncomfortable.

[0072] Also, when the preceding vehicle shifts to the constant-speed running state from the accelerating state as shown in FIG. 6 (a), the preceding vehicle acceleration limit 3 at t ₁₃ the transition to a constant speed running state Since the preceding vehicle acceleration / deceleration Gt (n) calculated in step S12 in the process becomes “0”, the process moves from step S13 to step S19 via step S18, and the acceleration upper limit G _UP is set to “0”. Therefore, the own vehicle also shifts from the acceleration state to the constant speed traveling state.

[0073] However, since the vehicle speed V of the solid line illustrated for the preceding vehicle speed Vt of the broken line shown as shown in the this time t ₁₃ FIG 6 (a) (n) ( n) is slow, the preceding vehicle and the subject The inter-vehicle distance D to the vehicle continues to increase with respect to the target inter-vehicle distance D ^* shown by the dashed line as shown by the solid line in FIG. 6C.

Then, when the own vehicle is driven at a constant speed,
Count the constant speed running duration in the acceleration limiting process of FIG.
The timer count value T is incremented sequentially.
And the count value T is₁₄Set value T_SETReached
Then, step S23 in the acceleration limiting process of FIG.
From step S25 to the current acceleration upper limit G _UP
Is the normal set value G_DEFJudge whether it is smaller than
Upper limit G_UPIs “0” and the normal set value G_DEFSmaller
Therefore, the process proceeds to step S26, where the current acceleration upper limit is set.
Value G_UPTo the new acceleration upper limit value.
G_UPThen, the process proceeds to step S16.

For this reason, the acceleration upper limit G _UP is equal to the predetermined value ΔG
Since the target acceleration / deceleration G ^* becomes larger than “0”, acceleration is permitted, and a large throttle opening θ is set in step S8 in FIG.
The shift position TS is set, the engine output control device 9 and the transmission control device 10 are controlled, and the vehicle shifts to an acceleration state.

[0076] At this time, since the preceding vehicle is maintained constant speed running condition, the inter-vehicle distance D begins to decrease from the time t ₁₄ as shown in FIG. 6 (c), then, each time repeating the process of FIG. 3 As the acceleration upper limit value G _UP increases, the acceleration state is continued with the acceleration gradually increasing, and the target inter-vehicle distance D ^* increases accordingly.

[0077] When the inter-vehicle distance D and the target inter-vehicle distance D ^* at time t ₁₅ matches, the process proceeds from step S4 to step S6 in the process of FIG. 2, the negative target acceleration corresponding to the deceleration G ^* by but is set, the vehicle is shifted to the deceleration state, by decreasing the target inter-vehicle distance D ^* be accordingly, at the time t ₁₆ the speed of the host vehicle V (n) is the preceding vehicle speed Vt ( n), and the inter-vehicle distance D is also in the following running control state, which also coincides with the target inter-vehicle distance D ^* .

As described above, when the preceding vehicle shifts from the acceleration state to the constant-speed running state, if the constant-speed running state exceeds a predetermined time _TSET , the vehicle automatically enters the acceleration permission state. It is possible to obtain an accurate following running control state in which the inter-vehicle distance D with respect to the preceding vehicle matches the target inter-vehicle distance D ^* .

In the first embodiment, a case where it is determined in step S18 in FIG. 3 whether or not the own vehicle is running at a constant speed based on the vehicle speed V (n) of the own vehicle will be described. However, the present invention is not limited to this. It is determined whether or not the vehicle is in a deceleration state in which the preceding vehicle acceleration / deceleration Gt (n) is negative. Step S21 when the vehicle is not traveling at a constant speed
It may be made to shift to.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, when the preceding vehicle continues the acceleration state for a predetermined time or longer, it is determined that the vehicle will shift to the next constant-speed traveling state, and the vehicle can immediately enter the acceleration state when the vehicle enters the constant-speed traveling state. It is like that.

That is, in the second embodiment, as shown in FIG. 7, between the steps S13 and S14 in the first embodiment, the acceleration continuation state flag F1 indicating that the acceleration state has continued for the set time or more is set. It is determined whether or not it is set to "1". When F1 = 0, the process proceeds to step S14, and when F1 = 1, the process proceeds to step S16.
Next, a step S32 for determining whether or not the acceleration start flag F2 indicating whether or not the vehicle is in the acceleration start state is set to "1" is provided.

When the result of the determination in step S32 is F2 =
If it is "0", the flow shifts to step S33 to set the acceleration start flag F2 to "1", and to clear the count value T1 of the acceleration time timer for counting the acceleration continuation time to "0", and then to step S34. To F2
If "1", the process directly proceeds to step S34.

In this step S34, it is determined whether or not the count value T1 of the acceleration time timer is equal to or _larger than a preset set value _TSET1 , and if T1 < _TSET1 , the _routine proceeds to step S35, where the acceleration time is set. After the count value of the timer is incremented by "1", the process proceeds to step S16.
The process _proceeds to S36 when T ≧ T _SET1 .

In step S36, step S12
It is determined whether or not the acceleration / deceleration Gt (n) of the preceding vehicle calculated in the above is less than a normal set value (default value) G _DEF (for example, about 0.03 G to 0.06 G), and Gt (n) ≧ G _DEF If there is, the process directly proceeds to step S16, and Gt
(n) If <G _DEF , the process proceeds to step S37 to set the normal set value G _DEF as the acceleration upper limit G _UP , and then to step S38 to proceed to the acceleration continuation flag F
After setting 1 to "1", the process proceeds to the step S16.

Step S18 in FIG. 3 is omitted, and steps S13 to S40 are performed instead.
Then, the acceleration continuation flag F1 is reset to "0", and the acceleration start flag F2 is reset to "0".
Next, the routine proceeds to step S41, where the preceding vehicle acceleration / deceleration G
It is determined whether or not the vehicle is in a deceleration state where t (n) is negative, and Gt
(n) When <0, the process proceeds to step S19,
Next, in step S20, the running state flag F is reset to "0", and the deceleration state flag F3 is set to "1" indicating the deceleration state. Then, the flow shifts to step S16, where Gt (n) = 0. Move to step S42.

In step S42, the deceleration state flag F
It is determined whether or not 3 is set to "1". If it is reset to "0", the process directly proceeds to step S16, and if it is set to "1", the process proceeds to step S21.

In the process of FIG. 7, step S31
Step S38 corresponds to acceleration upper limit value setting means. Therefore, it is assumed that the own vehicle and the preceding vehicle have stopped at a predetermined inter-vehicle distance, and when the preceding vehicle starts running from this state, the steps S13 to S31 are performed in the same manner as in the first embodiment. After that, the process proceeds to step S14, and the acceleration upper limit G _UP is set to the preceding vehicle acceleration / deceleration Gt (n), and the vehicle starts running.

At this time, steps S32 to S
The flow shifts to 33, where the acceleration start flag F2 is set to "1", and the count value T1 of the acceleration time timer is cleared to "0".

Next, from step S34 to step S3
The process proceeds to step 5, where the count value T1 of the acceleration time timer is incremented by "1". Thereafter, when the processing of FIG. 7 is executed again after the timer interruption time has elapsed, since the acceleration start flag F2 is set to "1", the process directly proceeds from step S32 to step S34, and then proceeds to step S35. After the transition, the increment of the count value T1 of the acceleration time timer is continued.

Thereafter, the acceleration state of the preceding vehicle is continued for a predetermined time, and the count value T1 of the acceleration time timer is set to the set value T.
_{When SET1} is reached, the process proceeds from step S34 to step S36, where the preceding vehicle acceleration / deceleration Gt (n) is set to the normal set value _GDEF.
If it is larger, the acceleration upper limit G _{UP is set} to the preceding vehicle acceleration / deceleration Gt (n), and the acceleration state of the own vehicle is continued.

[0091] However, an attempt to transition the preceding vehicle is in the constant speed running state, preceding the vehicle acceleration or deceleration Gt (n) is typically less than the set value G _DEF, shifts from step S36 to step S37, the acceleration upper limit value G _UP Is returned to the normal set value _GDEF from the preceding vehicle acceleration / deceleration Gt (n), and then the acceleration continuation flag F1 is set to "1" in step S38.

For this reason, when the process of FIG. 7 is executed next, the process directly proceeds from step S31 to step S16, and the acceleration upper limit G _UP becomes the normal set value G _DEF.
Maintain the state set to.

As a result, the acceleration upper limit G _UP becomes larger than the preceding vehicle acceleration / deceleration Gt (n), so that the acceleration upper limit G _UP is set to the preceding vehicle acceleration / deceleration Gt (n). The acceleration control is performed so that the inter-vehicle distance D matches the target inter-vehicle distance D ^* by permitting further acceleration due to the tendency that the inter-vehicle distance with the preceding vehicle increases.

Thereafter, when the preceding vehicle shifts to the constant speed running state, the preceding vehicle acceleration / deceleration Gt (n) becomes "0", so that the process shifts from step S13 to step S40 in FIG. Is reset to "0", and the acceleration start flag F2 is reset to "0". Then, the process proceeds to step S42 via step S14. Since the deceleration state flag F3 is reset to "0", the acceleration upper limit value is reset. The state in which G _UP is set to the normal set value G _DEF is maintained, the acceleration state is continued, and the following distance D matches the target following distance D ^* .

By the way, when the preceding vehicle shifts from the accelerating state to the decelerating traveling state instead of the constant speed traveling state, the preceding vehicle acceleration / deceleration Gt (n) becomes negative. , Steps S41 to S19
Then, the acceleration upper limit G _UP is set to “0”, then, in step S20, the running state flag F is reset to “0”, and the deceleration state flag F3 is set to “1”.

For this reason, when the processing of FIG. 7 is executed next, the process proceeds from step S41 to step S21 via step S42, and the same acceleration suppression control as in the first embodiment is executed.

In each of the above embodiments, a case is described in which the target inter-vehicle distance D ^* is calculated, and the target inter-vehicle distance D ^* is compared with the actual inter-vehicle distance D to calculate the target acceleration / deceleration G ^*. Although described above, the present invention is not limited to this, and the time until the host vehicle reaches L ₀ (m) behind the preceding vehicle based on the inter-vehicle distance D (n) (inter-vehicle time)
T ₀ determines the target vehicle speed V ^* (n) to be constant, and calculates an engine output command value α based on the deviation [Delta] V (n) of the actual vehicle speed V (n) and which, which is positive Sometimes,
The engine is controlled to an acceleration state based on the calculated engine output command value α, and when negative, the speed deviation ΔV
The target braking pressure may be set by PD control or PID control based on (n).

In each of the above embodiments, 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. However, the present invention is not limited to this. Detecting the output speed and calculating the vehicle speed,
The vehicle speed calculating means used in the antilock brake control device can be applied.

Further, in each of the above embodiments, 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. .

Further, in the above embodiment, the case where the present invention is applied to a rear wheel drive vehicle has been described.
The present invention can be applied to a front-wheel drive vehicle or a four-wheel drive vehicle. Further, the present invention can be applied to an electric vehicle using an electric motor instead of the engine 2 or a hybrid vehicle using the engine 2 and the electric motor together. Can be done. 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 a first 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 an acceleration limiting 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 first embodiment when the preceding vehicle shifts from an acceleration state to a deceleration state.

FIG. 6 is a time chart for explaining the operation of the first embodiment when a preceding vehicle shifts from an acceleration state to a constant-speed running state.

FIG. 7 is a flowchart illustrating a specific example of an acceleration limiting process according to the second embodiment of the present invention.

FIG. 8 is a time chart for explaining a follow-up running control operation of a conventional example.

[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 14 Front-rear acceleration sensor 20 Travel control Controller

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G01S 13/93 G08G 1/16 E G08G 1/16 G01S 13/93 Z

Claims (5)

[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 target acceleration / deceleration setting means for setting a target acceleration / deceleration such that the inter-vehicle distance detected by the inter-vehicle distance detection means coincides with a target inter-vehicle distance; and maintaining the target acceleration / deceleration set by the target acceleration / deceleration setting means. Traveling control means for controlling the traveling, and when the target acceleration is set by the target acceleration / deceleration setting means, the target acceleration is estimated or detected. Running control device for vehicles. 2. An acceleration correction means for detecting or estimating the acceleration of a preceding vehicle, and an acceleration upper limit value setting the preceding vehicle acceleration calculated by the preceding vehicle acceleration calculation means as an acceleration upper limit value. 2. An apparatus according to claim 1, further comprising: means for limiting the target acceleration to the acceleration upper limit when the target acceleration set by the target acceleration setting means exceeds the acceleration upper limit. Travel control device for vehicles. 3. The acceleration upper limit value setting means determines whether or not the preceding vehicle is in an acceleration state, and when the vehicle is in an acceleration state, sets the acceleration of the preceding vehicle in place of the normal set value as the acceleration upper limit value. The acceleration upper limit value is set to zero when the vehicle is shifted from this acceleration state to another traveling state, and is returned to the normal set value when the constant speed traveling state continues for a predetermined time or more during this time. 3. The vehicle travel control device according to claim 2, wherein: 4. The vehicle travel control device according to claim 3, wherein said acceleration upper limit value setting means gradually returns the acceleration upper limit value to a normal set value. 5. The acceleration upper limit value setting means determines whether or not the preceding vehicle is in an acceleration state, and when the vehicle is in an acceleration state, sets the preceding vehicle acceleration instead of the normal set value as the acceleration upper limit value. When the set state continues for a set time or more and the preceding vehicle acceleration becomes less than the normal set value, the acceleration upper limit value is returned to the normal set value. The vehicle travel control device according to claim 2.