JPH11348746A - Driving controlling device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving controlling device for a vehicle giving a driver no unusual sense of feeling such as deceleration shock or brake missing at start, release or under control of deceleration and capable of smooth switching to a manual control state from an automatic control state by the driver at release. SOLUTION: A target deceleration speed of its own car αe is calculated from its own speed Ve, precedent car speed Vf, inter-vehicle distance L and target inter-vehicle distance, and a barking device is operated and controlled based on the calculated target deceleration speed αe. When the target deceleration speed αe calculated is rapidly changed, the target deceleration speed αe is controlled (S62, S68, S72, S76, S80) by a gradually changed control value e.g. αemax (t)1} by a target deceleration speed controlling means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling control device for a vehicle, and more particularly, to a deceleration control technique in traveling control.

[0002]

2. Related Background Art In recent years, in order to reduce the driving operation of an automobile, a travel control device having an inter-vehicle distance control device for pursuing a preceding vehicle has been developed and put into practical use.

[0003] A traveling control device provided with this inter-vehicle distance control device detects an inter-vehicle distance between a host vehicle and a preceding vehicle based on information from a forward recognition device such as a camera or a laser radar. The engine output and the braking force are adjusted so that the distance becomes a preset target inter-vehicle distance, thereby accelerating and decelerating the vehicle and tracking the preceding vehicle.

Normally, in such tracking driving control, a target deceleration is calculated based on a relative speed between the own vehicle speed and a preceding vehicle speed. When the vehicle is decelerated, the target deceleration is calculated based on the target deceleration. The braking force is adjusted to control the vehicle deceleration.

[0005] However, when the deceleration control is performed based on the target deceleration, a large target deceleration suddenly appears or disappears when the deceleration control is started or canceled, and the occupant may be disturbed. There has been a problem that the driver feels discomfort such as deceleration shock or brake loss.

[0006] In this regard, mainly regarding the release timing of the deceleration control (automatic braking control), the deceleration control is performed when the driver operates the accelerator after the target deceleration (approach) becomes smaller than a predetermined value and the inter-vehicle distance becomes large. A control device configured to cancel the brake is disclosed in Japanese Patent Application Laid-Open No. H8-310359 and the like. According to this control, a feeling of discomfort such as a brake slippage is eliminated, and the automatic braking state is changed to a manual braking state by the driver. Switching to is smoothly performed.

[0007]

The start and release of the deceleration control are not limited to those disclosed in the above-mentioned publications, for example, when the deceleration control is started by the start operation of the tracking drive control. Alternatively, when the accelerator is temporarily operated during acceleration (override) during acceleration control, acceleration control (override) may be temporarily canceled and restarted. In addition, the deceleration control may be started or canceled according to various vehicle running conditions. Further, there is a case where the deceleration control is limited in order to keep the target deceleration small according to the vehicle running state.

[0008] Even in such a case, the occupant may feel a sense of incongruity such as a deceleration shock or a brake slippage as described above, which is not preferable.

Further, even during normal control, if the degree of change in the target deceleration is large, the target deceleration changes abruptly, which may cause the occupant to feel discomfort similar to a deceleration shock. is there.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to make a driver feel a sense of discomfort such as deceleration shock or brake loss when starting, releasing, or limiting deceleration control. It is an object of the present invention to provide a travel control device for a vehicle that does not have any problem and can realize smooth switching from an automatic braking state to a manual braking state by a driver at the time of release.

[0011]

To achieve the above object, according to the first aspect of the present invention, the vehicle speed of the own vehicle is controlled so that the inter-vehicle distance between the own vehicle and the preceding vehicle becomes the target inter-vehicle distance. In a travel control device for a vehicle that performs travel control, a target deceleration calculation unit calculates a target deceleration of the own vehicle based on the own vehicle speed, a preceding vehicle speed, an inter-vehicle distance, and a target inter-vehicle distance. Is controlled based on the calculated target deceleration. However, when the calculated target deceleration suddenly changes, the target deceleration is controlled by the target deceleration limiting means. Is limited by a limit value that gradually changes toward the target deceleration.

Therefore, for example, immediately after the tracking drive control is started based on the driver's intention or during the tracking drive control, the driver operates the accelerator pedal to accelerate (override), and the tracking drive control is temporarily interrupted. Then, when the target deceleration is suddenly generated, such as immediately after the accelerator pedal is returned and the tracking driving control is restarted, the target deceleration is limited so as to gradually increase with the elapse of time. Shock is prevented. Further, by gradually changing the target deceleration, the driver can be urged to operate the brake pedal with a margin when braking is required, and the vehicle can be driven while respecting the driver's intention.

[0013] Further, in a case where the tracking traveling control is not performed when the own vehicle speed is equal to or lower than the predetermined low vehicle speed, the target deceleration is set to be large when the own vehicle speed becomes equal to or lower than the predetermined low vehicle speed. However, for example, the target deceleration is limited so as to gradually decrease with a decrease in the vehicle speed, that is, the braking is not suddenly released, and the occurrence of an uncomfortable feeling such as a missing brake is prevented. Furthermore, by gradually changing the target deceleration, it is possible to suggest the operation of the brake pedal to the driver when braking is required continuously, and to shift from automatic driving to driving according to the driver's operation. Can be smoothly realized.

When the preceding vehicle speed is equal to or lower than a predetermined low vehicle speed, the deceleration control is interrupted on the assumption that the preceding vehicle turns right or left. Even if it is large, for example, the target deceleration is limited so as to gradually decrease with a decrease in the preceding vehicle speed, so that the braking is not suddenly released, and the occurrence of an uncomfortable feeling such as a missing brake is prevented. You. Further, as described above, the driver can be instructed to operate the brake pedal.

Further, when the inter-vehicle distance is large, the target deceleration is gradually reduced with an appropriate degree of change so that the vehicle does not mistakenly recognize a fixed object other than the vehicle in front as a new preceding vehicle and does not suddenly brake. .

Further, even if the target deceleration greatly changes during the normal deceleration control, the rising gradient of the target deceleration is limited according to the target deceleration, and the deterioration of the traveling feeling is also prevented. .

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown a schematic configuration diagram of a traveling control device according to the present invention mounted on a vehicle 1. Hereinafter, the traveling control device according to the present invention will be described with reference to FIG. The configuration will be described.

At the front of the vehicle 1, a laser beam is emitted toward the front, and by scanning this laser beam, an object located in front of the vehicle 1 can be recognized, and the distance to the object can be measured. A simple scanning laser radar 2 is provided. In addition, the vehicle 1
A CCD camera 4 for capturing an image in front of is mounted. The CCD camera 4 is also capable of recognizing an object located in front, a lane (white line), and the like.

The engine 6 is connected with a throttle valve 8 for controlling the amount of intake air to the engine 6 and adjusting the engine output. More specifically, the throttle valve 8 can automatically adjust the valve opening based on an operation signal output from an electronic control unit (ECU) 50 to be described later according to the opening of an accelerator pedal (not shown) or the like. A simple throttle actuator 12 is provided.

Service brakes (braking devices) 24 such as hydraulic disc brakes are provided on a pair of left and right front wheels (drive wheels) 20 and a pair of right and left rear wheels (sub wheels) 22, 22, respectively. Reference numeral 24 is connected to a brake pedal 28 via a brake master cylinder 26 having a negative pressure booster. Further, the brake master cylinder 26 is provided with a negative pressure type brake actuator 30 capable of automatically operating the service brake 24 in response to an operation signal from the ECU 50 regardless of an input from the brake pedal 28.

A wheel speed sensor 32 for detecting a right wheel speed VSR and a left wheel speed VSL is provided in the vicinity of the rear wheels 22, 22, which are slave wheels, corresponding to each wheel.
These wheel speed sensors 32 function as host vehicle speed detecting means for detecting the host vehicle speed Ve.

On a steering column 36 of a steering wheel 34 provided in the cabin of the vehicle 1, a tracking travel switching operation switch 38 for switching a travel control device of the vehicle 1 between a normal traveling state and a traveling state by tracking traveling control is provided. Is provided. When the tracking travel changeover operation switch 38 is operated to the set side, the inter-vehicle distance control, that is, the tracking travel control is started, and when it is operated to the reset side, the inter-vehicle distance control is released.

The ECU 50 is a main control device that controls various controls of the vehicle 1. As shown in the figure, the input side of the ECU 50 is connected to various sensors and switches such as the scanning laser radar 2, the CCD camera 4, the wheel speed sensors 32, 32, and the tracking drive switch 38. ,
Various driving devices such as a throttle actuator 12 and a brake actuator 30 are connected to the output side.

Hereinafter, control contents of the cruise control device configured as described above, that is, functions and effects according to the present invention will be described.

Referring to FIG. 2, there is shown a flowchart of a tracking drive control routine. Hereinafter, a control procedure of the tracking drive control according to the present invention will be described with reference to FIG.

When the tracking travel changeover switch 38 is operated to the set side to start the tracking travel control, first, in step S10, a preceding vehicle determination process is performed. Specifically, in step S10, when an object is recognized in front of the vehicle 1 based on information from the scanning laser radar 2 and the CCD camera 4, it is determined whether or not the object is a vehicle. If it is determined that the vehicle is a vehicle, the vehicle is determined to be a preceding vehicle. When there are a plurality of preceding vehicles, for example, a vehicle located on the own vehicle lane recognized by the CCD camera 4 or on the own vehicle lane estimated from the own vehicle steering wheel angle is determined as the preceding vehicle. As a result, the preceding vehicle is determined. Since the method of determining the preceding vehicle has no direct relation to the present invention, a detailed description thereof will be omitted.

In step S12, the wheel speed sensor 3
The vehicle speed of the vehicle 1, that is, the host vehicle speed Ve is calculated based on the information from the host vehicles 2 and 32 (host vehicle speed detecting means). Here, the vehicle speed Ve is calculated, for example, by the following equation (1).

Ve = (VSR + VSL) / 2 (1) That is, the own vehicle speed Ve is an average value of the right wheel speed VSR and the left wheel speed VSL.

In step S14, the distance from the own vehicle to the preceding vehicle, that is, the inter-vehicle distance L is accurately measured based on the information from the scanning laser radar 2.

In the next step S16, the relative speed Vr between the host vehicle and the preceding vehicle is calculated based on the inter-vehicle distance information L. More specifically, the relative speed Vr is calculated based on the value of the inter-vehicle distance information L when the routine was last executed, that is, the amount of change ΔL between the previous value and the current value. At this time, if the change amount ΔL is positive and the relative speed Vr is positive, it is considered that the own vehicle is moving away from the preceding vehicle. If the change amount ΔL is negative and the relative speed Vr is negative, the own vehicle approaches the preceding vehicle. Can be considered to be.

In step S18, the preceding vehicle speed Vf is calculated from the following equation (2) based on the own vehicle speed Ve and the relative speed Vr (preceding vehicle speed detecting means).

Vf = Ve + Vr (2) Here, the preceding vehicle acceleration αf is also calculated by differentiating the preceding vehicle speed Vf. Specifically, the preceding vehicle acceleration αf is calculated from the change amount ΔVf between the previous value and the current value of the preceding vehicle speed information Vf when the routine was last executed.

In the next step S20, the target deceleration αe of the own vehicle is calculated.

Referring to FIG. 3, there is shown a calculation processing routine of the target deceleration αe, and the calculation procedure of the target deceleration αe will be described below with reference to the flowchart.

In step S40, first, a target deceleration αer of the own vehicle during deceleration running of the preceding vehicle is calculated from the following equation (3).

Αer = −Vr · Ve / (L−Lo) (3) Here, Lo is secured at a minimum between the own vehicle and the preceding vehicle when it is assumed that the preceding vehicle has decelerated and stopped. Indicates the minimum distance to be driven.

The minimum inter-vehicle distance Lo is equal to the inter-vehicle distance L.
And the inter-vehicle distance L is a value L
If you are more than 1 (for example, 25m) apart,
The minimum inter-vehicle distance Lo is set to a value 0, and when the inter-vehicle distance L becomes less than the value L1, the minimum inter-vehicle distance Lo becomes a value Lo1 (for example, 10
m).

That is, when the inter-vehicle distance L becomes small and the own vehicle approaches the preceding vehicle, the target deceleration αer is increased so as to secure at least the minimum inter-vehicle distance Lo. They try to avoid contact.

Subsequently, in step S42, the target deceleration αec of the own vehicle while the preceding vehicle is traveling at a constant speed is calculated from the following equation (4) (target deceleration calculating means).

[0040] ^{αec = Vr 2/2 · (} L-Lf · L / La) + αa ... (4) Here, Lf is the target inter-vehicle distance based on the preceding vehicle speed calculated according to the preceding vehicle speed Vf. Specifically, a map indicating the relationship between Vf and Lf as shown in FIG. 4 is preset and stored in the ECU 50, and the target inter-vehicle distance Lf is obtained from the map.

That is, when the minimum inter-vehicle distance Lo is 0
, The target inter-vehicle distance Lf1 and the target inter-vehicle distance Lf2 when the minimum inter-vehicle distance Lo is a value Lo1 (for example, 10 m).
Is selected as the target inter-vehicle distance Lf. When the preceding vehicle speed Vf is large, the target inter-vehicle distance Lf becomes the target inter-vehicle distance Lf.
When the preceding vehicle speed Vf decreases, the vehicle speed is set based on the target inter-vehicle distance Lf2 so as to secure at least the minimum inter-vehicle distance Lo.

By the way, in the same equation, the target inter-vehicle distance Lf is L
/ La is multiplied by L / La, which is a correction coefficient provided in consideration of a case where another vehicle suddenly intervenes between the own vehicle and the preceding vehicle.

Here, La is the vehicle speed Ve and the relative speed Vr.
Is the braking start distance when the own vehicle approaches the preceding vehicle, and Ve, Vr and L as shown in FIG.
This is set based on a map indicating the relationship with a.

In other words, if another vehicle suddenly interrupts, the following distance L indicates a new distance between the other vehicle and the host vehicle, and the new distance L is applied at once. The start distance La is often within the range of the start distance La. In such a case, the braking start distance L of the inter-vehicle distance L is used.
The target inter-vehicle distance Lf is corrected (reduced) according to the degree of interruption to a, that is, L / La.

Thus, when another vehicle suddenly cuts in, the target deceleration αer is changed to a small value by reducing the target inter-vehicle distance, and the vehicle decelerates slowly without sudden braking. Thus, the occupant of the vehicle 1 is preferably prevented from feeling a deceleration shock.

In the case where the vehicle ahead is satisfactorily tracked without interruption by another vehicle, or after the interruption, the inter-vehicle distance L to the other vehicle gradually increases and becomes larger than the braking start distance La. Correction factor L /
When La exceeds the value 1, the correction coefficient L / La becomes the value 1
The target inter-vehicle distance is set to the normal target inter-vehicle distance Lf based on the map of FIG.

In the above equation, αa is a correction value based on the fluctuation of the preceding vehicle acceleration αf, and is calculated by the following equation (5).

Αa = αf · (L−Le · L / La) / (L−Lf · L / La) (5) where Le is the target inter-vehicle distance during the follow-up control set based on the own vehicle speed Ve. It is. Specifically, as shown in FIG. 6, a map indicating the relationship between Ve and Le similar to that of FIG. 4 is previously set and stored in the ECU 50, and the target inter-vehicle distance Le is obtained from the map.

In the formula for calculating the correction value αa, the target inter-vehicle distance Le and the target inter-vehicle distance Lf are determined by the correction coefficient L
/ La, so that the correction value αa is an appropriate correction value in consideration of interruption of another vehicle.

When the target deceleration αer of the own vehicle during the deceleration running of the preceding vehicle and the target deceleration αec of the own vehicle during the running at a constant speed of the preceding vehicle are obtained as described above, the following steps S44 and S46 are performed. The weights for the target deceleration αer and the target deceleration αec are obtained.

In step S44, first, the preceding vehicle acceleration α
Calculate the weight W1 based on f.

More specifically, a map indicating the relationship between the preceding vehicle acceleration αf and the weight W1 as shown in FIG. 7 is preset and stored in the ECU 50, and the weight W1 is obtained from the map.

That is, the weight W1 gradually increases from the value 0 when the acceleration αf of the preceding vehicle decreases to the negative side, that is, when the deceleration of the preceding vehicle increases and becomes equal to or less than the predetermined value αf1 (for example, -0.05G). , Is set to a value of 1 when a predetermined value αf2 (for example, −0.2 G) is reached.

In step S46, a weight W2 based on the tracking state counter CNT is calculated.

More specifically, a map indicating the relationship between the tracking state counter CNT and the weight W2 as shown in FIG.
2 is determined from the map.

Here, the tracking state counter CNT indicates that the vehicle 1
Is a counter that is incremented every execution cycle of the routine when the vehicle is in the tracking state with respect to the preceding vehicle. When at least the following conditions 1) to 3) are satisfied, it is determined that the vehicle is in the tracking state and is added. I have.

1) (control state) ≠ (braking control) 2) L <Le · 3/2 3) | Vr | <Vr1 (for example, 5 km / h) That is, when the vehicle 1 enters the tracking state, the tracking state counter CNT
Is started to be added, but the weight W2 is
The tracking state counter CNT has a predetermined value CNT1 (for example, 0.5 s).
The value is set so as to gradually increase from the value 0 when exceeding a value corresponding to ec, and to become the value 1 when reaching a predetermined value CNT2 (for example, a value corresponding to 2.0 sec). That is, the weight W2 approaches the value 1 as the duration of the tracking state becomes longer.

As described above, when the weight W1 based on the preceding vehicle acceleration αf and the weight W2 based on the tracking state counter CNT are obtained from the respective maps, in the next step S48, the weight W1, the weight W2 and the previous value Wn− The largest one among 1 is selected, and this value is set as the weight W.

In step S50, the weighted average of the target deceleration αer during deceleration running of the preceding vehicle and the target deceleration αec during deceleration running of the preceding vehicle is calculated by taking the weight W into consideration. And the weighted average value is finally set as the target deceleration αe.

Αe = αec · (1−W) + αer · W (6) As described above, by calculating the target deceleration αe by taking the weight W into consideration, for example, the own vehicle can move ahead from a distant vehicle. If the target deceleration αe is switched from the target deceleration αec to the target deceleration αer after decelerating according to the traveling state of the preceding vehicle after traveling at a constant speed in order to catch up with the target deceleration αe
Does not suddenly switch from the target deceleration αec to the target deceleration αer, and the occupant of the vehicle 1 is preferably prevented from feeling uncomfortable.

Therefore, for example, in a situation where the preceding vehicle is running at a constant speed and the own vehicle can catch up with the preceding vehicle from a distance, the preceding vehicle acceleration αf, that is, the preceding vehicle deceleration is small, and
The weight W1 has a value of 0 or its vicinity, and the tracking state counter CNT also does not satisfy the above conditions, so that the weight W2 also has a value of 0 or its vicinity. Therefore, in this case, the weight W is set to the value 0 or its vicinity, and the target deceleration αe is set mainly based on the target deceleration αec.

On the other hand, when the own vehicle catches up with the preceding vehicle and enters the tracking state, the tracking state counter CNT starts to be added, and in this case, the weight W2 and, consequently, the weight W gradually increase, and the target deceleration increases. αe gradually shifts from the target deceleration αec to the target deceleration αer. That is, when the tracking state continues to some extent, the target deceleration αe is switched in advance so as to be gradually calculated based on the target deceleration αer. Therefore, even when the preceding vehicle decelerates thereafter, the target deceleration αe is not suddenly switched, and the occupant is preferably prevented from feeling uncomfortable.

When the preceding vehicle decelerates immediately after the own vehicle catches up with the preceding vehicle and enters the tracking state, the preceding vehicle acceleration αf decreases on the negative side, that is, the preceding vehicle deceleration increases, and the weight of the preceding vehicle decreases. W1 gradually increases. Therefore, in this case, the weight W gradually becomes the value 1 without waiting for the increase of the weight W2, the target deceleration αe is promptly changed, and the target deceleration αec gradually shifts to the target deceleration αer. . Therefore, also in this case, the target deceleration αe is not suddenly switched, and the occupant is preferably prevented from feeling uncomfortable.

By the way, as described above, the target deceleration α
e is calculated, but in the tracking travel control,
In applying the target deceleration αe to actual control, a hysteresis is provided between the output value of the target deceleration αe, that is, the target deceleration output αe-out and the target deceleration input αe-in.

That is, referring to FIG. 9, there is shown a hysteresis relationship (solid arrow) between the target deceleration output αe-out and the target deceleration input αe-in. As shown in FIG. When the deceleration αe increases, the slope K becomes the value 1
(K = 1) and the target deceleration output αe-out is set to the same value as the target deceleration input αe-in, while the target deceleration αe
When the target deceleration input αe-in is equal to or larger than the predetermined value Xi1, the slope K is a value 1 (K = 1) but decreases along the offset line, and the target deceleration input αe-in becomes the predetermined value. When the target deceleration output αe-out is smaller than the value Xi1 and the target deceleration output αe-out is smaller than the predetermined value Xo1, the gradient K becomes equal to the value K1 (K1>
1, e.g., 1.4).

Thus, the normal target deceleration input αe-in
Varies minutely due to changes in the behavior of the preceding vehicle and disturbances due to noise in the signal output from the scanning laser radar 2. Especially when the own vehicle approaches the preceding vehicle, the noise increases and the fluctuation increases. Thus, even in the case where the target deceleration input αe-in fluctuates, the fluctuation of the target deceleration output αe-out, that is, the target deceleration αe is suitably prevented.

Returning to FIG. 2, in step S22, the own vehicle speed Ve detected in step S12 is reduced to a predetermined low vehicle speed Ve0.
(For example, 40 km / h). If the determination result is false (No) and the vehicle speed Ve is equal to or lower than the predetermined low vehicle speed Ve0, it is generally determined that the vehicle 1 is traveling in the city and the driver frequently operates the brake pedal 28. Then, the routine exits without performing the tracking control.

On the other hand, if the decision result in the step S22 is true (Y
If the own vehicle speed Ve is higher than the predetermined low vehicle speed Ve0 in es), the process proceeds to step S24.

In step S24, it is determined whether or not the own vehicle should be decelerated. That is, here, it is determined whether to perform the braking control or the throttle control. More specifically, the braking control is performed when the following conditions 1) to 3) are satisfied.

1) During tracking travel control 2) Vr <0 3) L <La or αer> αer1 That is, in the step S24, the relative speed Vr becomes negative during the tracking travel control, and the inter-vehicle distance L becomes the braking start distance La. Is determined, or whether the target deceleration αer of the own vehicle during deceleration traveling of the preceding vehicle exceeds a predetermined value αer1 set in advance.

The determination result of step S24 is false (No)
If any of the above conditions is not satisfied, the process proceeds to step S26 to perform throttle control. The throttle control is for controlling the throttle actuator 12 according to the running state, but is not directly related to the present invention, so that the description is omitted here.

On the other hand, if the decision result in the step S24 is true (Y
If it is determined in es) that the above conditions are satisfied, the process proceeds to step S28 to execute braking control (braking control means).

In step S28, throttle closing control is performed in executing the braking control. That is, the throttle valve 8 is closed by the throttle actuator 12 to prevent the vehicle 1 from being accidentally accelerated during braking.

In the next step S30, various clip controls are performed. Specifically, in step S28, various clip controls for the target deceleration αe, that is, various limit controls are performed (target deceleration limiting means).

As the limiting control of the target deceleration αe, for example, the limiting control for gradually changing the target deceleration αe immediately after the tracking driving control switch 38 is operated to start the tracking driving control, Accelerator pedal (not shown)
To decelerate α after acceleration (override)
In addition to the limiting control for gradually changing e, the limiting control for tailing immediately after the own vehicle speed Ve becomes equal to or lower than the predetermined low vehicle speed Ve0 (for example, 40 km / h), the preceding vehicle speed Vf becomes the predetermined low vehicle speed Vf0 (for example, 25 km / h) or less, there are limit control for tailing, limit control when the inter-vehicle distance L is large, control for limiting the rising slope of the target deceleration αe, and the like. Hereinafter, each of these limit controls will be described.

Referring to FIGS. 10 and 11, there are shown flowcharts of various clip control routines, which will be described below in accordance with the routines.

In step S60, first, it is determined whether or not a predetermined time t1 (for example, 4 seconds) has elapsed after the driver operates the tracking travel switching operation switch 38 to start the tracking travel control. If the determination result is true (Yes) and it is determined that the predetermined time t1 (for example, 4 seconds) has elapsed since the start of the tracking drive control, the process directly proceeds to step S64. On the other hand, if the determination result is false (No) and it is determined that the predetermined time t1 has not yet elapsed since the start of the tracking drive control, the process proceeds to step S64 after executing step S62.

In step S62, immediately after the start of the tracking drive control, a limit control for gradually changing the target deceleration αe is performed. Specifically, as shown in FIG. 12, a map indicating a time change of the target deceleration limit value αemax (t) 1 immediately after the start of the tracking drive control is set in advance, and the target deceleration αe is set to a value shown in FIG. Limited based on map. That is, the target deceleration limit value αemax (t) 1 is equal to the predetermined time t0 (for example, 2 seconds).
, And gradually increases as time t elapses from the predetermined time t0 to the predetermined time t1, and the target deceleration αe is maintained until the predetermined time t1 elapses. , The target deceleration limit value αemax (t)
The maximum value is limited by 1 (αe ≦ αemax (t)
1).

That is, according to the clip control, a sudden occurrence of a large target deceleration αe immediately after the start of the tracking drive control is suppressed.

As a result, the vehicle 1 does not suddenly brake immediately after the driver operates the tracking / running changeover operation switch 38, and the occupant is preferably prevented from feeling a deceleration shock and the running feeling is improved. Is achieved.

Further, since the vehicle 1 is gradually decelerated, the clip control has an effect of urging the driver to operate the brake pedal 28 when braking is necessary, and respects the driver's intention. Travel is allowed.

In the tracking travel control, the maximum value of the target deceleration αe is limited to a predetermined value X1 (for example, 0.25 G) based on requirements such as travel feeling. Therefore, the target deceleration limit value αemax (t) 1 is changed from the value 0 to the predetermined value X1.
(The same applies hereinafter).

In step S64, it is determined whether or not the driver has operated the accelerator pedal during the braking control to perform the override. If the determination result is false (No) and the override has not been performed, the process directly proceeds to step S70. On the other hand, when the determination result is true (Yes) and it is determined that there is an override, the process proceeds to step S66.

In step S66, it is determined whether or not a predetermined time t3 (for example, 4 seconds) has elapsed after the end of the override. If the determination result is true (Yes), the process proceeds directly to step S70. If the determination result is false (No), and it is determined that the predetermined time t3 has not yet elapsed since the end of the override, step S68 is performed. After executing the process, the process proceeds to step S70.

In step S68, a restriction control for gradually changing the target deceleration αe after the end of the override is performed.
More specifically, as shown in FIG. 13, a map indicating a time change of the target deceleration limit value αemax (t) 2 after the end of the override is set in advance, and the target deceleration αe is limited based on the map of FIG. Is done. That is, the target deceleration limit value αem
ax (t) 2 is kept at 0 until a predetermined time t2 (for example, 2 sec) is reached, and gradually increases to a predetermined value X1 as the time t elapses from the predetermined time t2 to the predetermined time t3. The target deceleration αe is set to the target deceleration limit value αema until the predetermined time t3 elapses.
x (t) 2 limits its maximum value (αe ≦ αemax
(t) 2).

That is, when the normal override is performed, the override travel has priority over the tracking travel control,
Although the tracking travel control is interrupted, according to the clip control, a sudden occurrence of a large target deceleration αe at the time when the override ends and the tracking travel control is restarted is suppressed.

As a result, the vehicle 1 is not suddenly braked immediately after the end of the override, so that the occupant is preferably prevented from feeling a deceleration shock, and the driving feeling is improved. In particular, when the driver operates the accelerator pedal in small increments, that is, when the override is performed once within a predetermined time t2 (for example, 2 seconds) after the override has been completed, the target deceleration αe becomes zero. It will be retained and the driver's intention will be respected.

Further, after the predetermined time t2 has elapsed, the vehicle 1 gradually decelerates.
When braking is required, the driver is required to
Also, there is an effect to evoke the operation of the vehicle, and it is possible to drive while respecting the driver's intention as described above.

In step S70, it is determined whether or not the vehicle speed Ve is equal to or lower than the predetermined low vehicle speed Ve0 (for example, 40 km / h). If the determination result is false (No) and the own vehicle speed Ve is higher than the predetermined low vehicle speed Ve0, the process directly proceeds to step S74, and if the determination result is true (Yes), the own vehicle speed V
If it is determined that e is equal to or lower than the predetermined low vehicle speed Ve0, the process proceeds to step S74 after executing step S72.

In step S72, limit control for tailing is performed immediately after the host vehicle speed Ve falls below the predetermined low vehicle speed Ve0 (for example, 40 km / h). See Figure 1
As shown in FIG. 4, a map indicating a change in the target deceleration limit value αemax (Ve) when the own vehicle speed Ve becomes equal to or lower than the predetermined low vehicle speed Ve0 is set in advance.
4 based on the map. That is, the target deceleration limit value αemax (Ve) is set to the predetermined value X1 until the vehicle speed Ve decreases to the predetermined low vehicle speed Ve0, but the target deceleration limit value αemax (Ve) is changed from the predetermined low vehicle speed Ve0 to the predetermined vehicle speed Ve1 (for example, 25 km / h), the value is set so as to gradually decrease to the value 0 and to be kept at the value 0 when the vehicle speed is equal to or less than the predetermined vehicle speed Ve1.
When the own vehicle speed Ve becomes equal to or lower than a predetermined low vehicle speed Ve0, the tailing process is performed while the maximum value is limited by the target deceleration limit value αemax (Ve) (αe ≦ αemax (Ve)).

That is, according to the clip control, there is a case where the target deceleration αe is increased when the own vehicle speed Ve falls below the predetermined low vehicle speed Ve0 (for example, 40 km / h). However, the target deceleration αe is gradually reduced without abruptly decreasing to the value 0 with the cancellation of the tracking travel control.

Thus, it is possible to preferably prevent the occupant from feeling as if the vehicle is accelerating (braking-off feeling) during decelerating traveling, thereby improving traveling feeling.

Further, since the deceleration state of the vehicle 1 is gradually released, the clip control also has an effect of suggesting a continuous operation of the brake pedal 28 to the driver when braking is necessary. When the tracking travel control is released, the transition from the automatic travel to the travel according to the driver's operation can be smoothly realized.

In step S74, it is determined whether or not the preceding vehicle speed Vf has become equal to or lower than a predetermined low vehicle speed Vf0. If the determination result is false (No) and the preceding vehicle speed Vf is higher than the predetermined low vehicle speed Vf0, the process directly proceeds to step S78, and if the determination result is true (Yes), the preceding vehicle speed Vf becomes the predetermined low vehicle speed Vf0.
When it is determined as follows, the process proceeds to step S78 after executing step S76.

In step S76, limit control for tailing immediately after the preceding vehicle speed Vf becomes equal to or lower than a predetermined low vehicle speed Vf0 (for example, 25 km / h) is performed. For details, see FIG.
As shown in FIG. 1, a map indicating a change in the target deceleration limit value αemax (Vf) when the preceding vehicle speed Vf becomes equal to or lower than the predetermined low vehicle speed Vf0 is set in advance.
Limited based on 5 maps. That is, the target deceleration limit value αemax (Vf) is set to the predetermined value X1 until the preceding vehicle speed Vf decreases to the predetermined low vehicle speed Vf0. However, the target deceleration limit value αemax (Vf) is changed from the predetermined low vehicle speed Vf0 to the predetermined vehicle speed Vf1 (for example, 10 km / h), the value is set so as to gradually decrease to the value 0 and to be kept at the value 0 when the vehicle speed is equal to or lower than the predetermined vehicle speed Vf1.
When the preceding vehicle speed Vf becomes equal to or lower than the predetermined low vehicle speed Vf0, the tailing process is performed while its maximum value is limited by the target deceleration limit value αemax (Vf) (αe ≦ αemax (Vf)).

This is a clip control assuming, for example, a case where the preceding vehicle is greatly decelerated to make a right or left turn.
That is, when the preceding vehicle is greatly decelerated to make a right or left turn, it is not necessary to decelerate the own vehicle. Thus, the preceding vehicle speed Vf becomes equal to or lower than the predetermined low vehicle speed Vf0 (for example, 25 km / h). In such a case, the target deceleration αe, which was once increased in accordance with the preceding vehicle, is limited so as to be gradually reduced.

As a result, the vehicle is prevented from decelerating by following the preceding vehicle that disappears from the front immediately after the vehicle turns right and left, so that braking against the driver's intention is suitably prevented, and deceleration is performed. The occupant is preferably prevented from feeling as if the vehicle were accelerating (braking-off feeling), and the running feeling is improved.

Further, since the deceleration state of the vehicle 1 is gradually released in the same manner as described above, in the clip control,
When braking is required, there is also an effect of suggesting the driver to continuously operate the brake pedal 28.

In step S78, it is determined whether or not the inter-vehicle distance L is greater than a predetermined distance L0 (for example, 50 m). When the determination result is false (No), the inter-vehicle distance L is the predetermined distance L0
In the following cases, the process directly proceeds to step S82 in FIG. 11, where the determination result is true (Yes) and the following distance L is equal to the predetermined distance L
If it is determined that it is larger than 0, step S80
, And the process proceeds to step S82.

In step S80, a restriction control is performed when the inter-vehicle distance L is large. Specifically, as shown in FIG. 16, the target deceleration limit value αemax when the inter-vehicle distance L is large.
A map indicating the change of (L) is set in advance, and the target deceleration αe is limited based on the map of FIG. That is, the target deceleration limit value αemax (L) is set to the predetermined value X1 until the inter-vehicle distance L becomes the predetermined distance L0 (for example, 50 m), but is set to a predetermined distance L1 (for example, 60 m) from the predetermined distance L0. Until the value X2 (for example,
0.1G), and when the distance is longer than the predetermined distance L1, the value X2
The target deceleration αe is set to
When the inter-vehicle distance L becomes larger than the predetermined distance L0, the maximum value is limited by the target deceleration limit value αemax (L) (αe ≦ αemax (L)).

In other words, when the inter-vehicle distance L is large, a roadside fixed object approaching from a distance may be erroneously recognized as a new preceding vehicle because of an inaccurate traveling lane estimation. Therefore, when the inter-vehicle distance L is equal to or longer than a predetermined distance L1 (for example, 60 m), the target deceleration αe is limited to the value X2 so that the target deceleration αe does not suddenly increase due to such erroneous recognition. According to the control, the limit value is gradually reduced at an appropriate degree of change without suddenly decreasing to the value X2 in accordance with the change in the accuracy of the travel lane estimation.

In step S82, it is determined whether or not the execution flag F of the rising slope limiting control of the target deceleration αe has a value of 1. The case where the value of the flag F is 1 means that the rising slope limiting control of the target deceleration αe described later is being performed when the target deceleration αe changes.

If the decision result in the step S82 is false (No) and the flag F is not 1, ie, if the gradient limit control is not performed and the flag F is 0, the process proceeds to a step S84.

In step S84, it is determined whether or not the rate of change Δαe when the target deceleration αe changes is equal to or greater than the gradient limit value Δαemax (αe).

Normally, when the target deceleration αe changes,
If the rate of change of the target deceleration αe is too large, the occupant tends to feel discomfort such as a deceleration shock. Therefore, in the tracking travel control, a limit value such as the slope limit value Δαemax (αe) is provided for the rate of change of the target deceleration αe.

This gradient limit value Δαemax (αe) is set in accordance with the target deceleration αe.
As shown in FIG. 7, the data is mapped in advance in accordance with the target deceleration αe by an experiment or the like. Specifically, the map shown in FIG. 17 shows the maximum value of the change rate Δαe at which the occupant of the vehicle 1 does not feel uncomfortable according to the target deceleration αe, and the gradient limit value Δαemax (αe) is the change rate Δαe Is the maximum value.

Therefore, the determination result of step S84 is false (N
In o), when the change rate Δαe is less than the gradient limit value Δαemax (αe), it can be determined that the occupant does not feel uncomfortable, and the routine ends as it is.

On the other hand, if the result of the determination in step S84 is true (Y
If the change rate Δαe is equal to or greater than the gradient limit value Δαemax (αe) in es), the process proceeds to step S86.

In step S86, the gradient limit value Δαemax
Based on (αe), the deceleration α at the time of changing the target deceleration αe is calculated from the following equation (7).

Α = Δαemax (αe) · T + α (n-1) (7) where T is the execution cycle of the routine, and α (n-1)
Is the previous value of the deceleration α.

That is, as shown by the broken line in FIG. 18, when the rate of change Δαe is equal to or larger than the gradient limit value Δαemax (αe), the occupant is more likely to feel uncomfortable, and
In such a case, the rate of change Δαe is limited to the gradient limit value Δαemax (αe) as shown by the solid line in FIG. 18 so as to alleviate the sense of discomfort.

At step S88, at step S86
It is determined whether or not the deceleration α obtained in the step has reached the changed target deceleration αe. If the determination result is false (No) and the deceleration α is less than the target deceleration αe, the value 1 is set to the flag F in step S90.

Then, the routine is repeatedly executed, and while the flag F is determined to be the value 1 in the determination in step S82, the deceleration α is continuously updated in step S86. Is false (No) and the deceleration α is equal to or greater than the target deceleration αe, the flag F is reset to the value 0 in step S92, and the updating of the deceleration α is ended.

When the above various clip controls are performed and the target deceleration αe is appropriately restricted by the various restriction controls, FIG.
Then, step S32 is executed.

In the step S32, the service brake 2
4 to calculate the braking force to be generated. Specifically, a braking force capable of generating the target deceleration αe determined as described above is calculated, and a signal value to be supplied to the brake actuator 30 is determined according to the braking force.

In step S34, a signal corresponding to the braking force is supplied to the brake actuator 30. As a result, the brake actuator 30 operates properly, and the service brake 24 generates a good and proper braking force.

As described above, in the traveling control device according to the present invention, the braking force is determined based on the target deceleration αe and the braking control of the tracking traveling control is performed, and the target deceleration αe changes greatly. In such a case, various clip controls are performed to limit the target deceleration αe and the rate of change Δαe.

Therefore, if the travel control device according to the present invention is used, a sudden change in the target deceleration αe is prevented, and the vehicle 1 suddenly decelerates or the deceleration state is suddenly released. Is appropriately eliminated, and the tracking drive control is realized without a sense of incongruity.

Also, by gradually decreasing or increasing the target deceleration αe, the driver can be urged to operate the brake pedal 28 with a margin or have an effect of suggesting the operation, and the tracking that respects the operation of the driver is also provided. It is possible to realize travel control, that is, travel control that improves the human interface.

[0120]

As described above in detail, according to the vehicle travel control apparatus of the first aspect, the vehicle speed is controlled such that the inter-vehicle distance between the own vehicle and the preceding vehicle becomes the target inter-vehicle distance. In the cruise control device of the vehicle performing the control, the target deceleration of the own vehicle is calculated based on the own vehicle speed, the preceding vehicle speed, the inter-vehicle distance, and the target inter-vehicle distance, but when the calculated target deceleration suddenly changes. The target deceleration is limited by a limit value that gradually changes toward the target deceleration after the sudden change.

Therefore, for example, immediately after the tracking drive control is started based on the driver's intention, or during the tracking drive control, the driver operates the accelerator pedal to accelerate (override), and the tracking drive control is temporarily interrupted. If the target deceleration occurs abruptly, such as immediately after the accelerator pedal is returned and the tracking driving control is resumed, the target deceleration can be limited to gradually increase with time, so that the deceleration shock is reduced. Can be prevented.

At this time, since the target deceleration is gradually changed, it is possible to prompt the driver to operate the brake pedal with a margin when braking is necessary, and to respect the driver's intention. Driving can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a traveling control device according to the present invention mounted on a vehicle.

FIG. 2 is a flowchart illustrating a tracking drive control routine according to the present invention.

FIG. 3 is a flowchart showing a routine for calculating a target deceleration αe in FIG. 2;

FIG. 4 shows a preceding vehicle speed Vf and a target inter-vehicle distance Lf based on the preceding vehicle.
It is a map showing the relationship with.

FIG. 5 is a map showing a relationship between a host vehicle speed Ve and a braking start distance La.

FIG. 6 is a map showing a relationship between a host vehicle speed Ve and a target inter-vehicle distance Le.

FIG. 7 is a map showing a relationship between a preceding vehicle acceleration αf and a weight W1.

FIG. 8 is a map showing a relationship between a tracking state counter CNT and a weight W2.

FIG. 9 shows a target deceleration output αe-out and a target deceleration input αe
It is a graph which shows the relationship of the hysteresis between -in.

FIG. 10 is a part of a flowchart showing a control routine of various clip controls in FIG. 2;

11 is the remaining part of the flowchart showing the control routine of various clip controls following the flowchart of FIG.

FIG. 12 is a map showing a temporal change of a target deceleration limit value αemax (t) 1 immediately after the start of tracking driving control.

FIG. 13 shows a target deceleration limit value αem after the end of the override.
9 is a map showing a temporal change of ax (t) 2.

FIG. 14 is a map showing a change in a target deceleration limit value αemax (Ve) when the host vehicle speed Ve becomes equal to or lower than a predetermined low vehicle speed Ve0.

FIG. 15 is a map showing a change in a target deceleration limit value αemax (Vf) when the preceding vehicle speed Vf becomes equal to or lower than a predetermined low vehicle speed Vf0.

FIG. 16 is a map showing a change in a target deceleration limit value αemax (L) when the inter-vehicle distance L is large.

FIG. 17 is a map showing a relationship between a target deceleration αe and a gradient limit value Δαemax (αe).

FIG. 18 is a diagram showing a time change of the deceleration α when the gradient limit value Δαemax (αe) is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle (own vehicle) 2 Scan type laser radar 24 Service brake (braking device) 28 Brake pedal 30 Brake actuator 32 Wheel speed sensor 38 Tracking drive switching operation switch 50 Electronic control unit (ECU)

Claims (1)

[Claims] 1. A traveling control device for a vehicle, which controls a vehicle speed of a vehicle and controls traveling so that a distance between the vehicle and a preceding vehicle becomes a target vehicle distance, wherein a braking force is automatically applied to the vehicle. A braking device; an inter-vehicle distance detecting means for detecting the inter-vehicle distance; an own vehicle speed detecting means for detecting the own vehicle speed; a preceding vehicle speed detecting means for detecting a preceding vehicle speed; and one of the own vehicle speed and the preceding vehicle speed. Target inter-vehicle distance calculating means for calculating the target inter-vehicle distance based on the own vehicle speed, the preceding vehicle speed, the inter-vehicle distance, and the target inter-vehicle distance, based on target deceleration calculating means for calculating a target deceleration of the own vehicle, When the target deceleration calculated by the target deceleration calculating means changes suddenly, target deceleration limiting means for limiting the target deceleration with a limit value gradually changing toward the target deceleration after the sudden change; Deceleration Travel control device for a vehicle, characterized by comprising a braking control means for controlling operation of the braking device based.