JP3237435B2 - Vehicle travel control device - Google Patents

Abstract

PURPOSE: To smoothly follow up the preceding vehicle by setting a set speed at constant speed running to be the vehicle speed at outputting a start command signal, and setting the set vehicle speed at tracking run to be higher than the vehicle speed at outputting the start command signal. CONSTITUTION: By beginning running control by an operation switch, when the present inter-vehicle distance D is larger than a set inter-vehicle distance Dset, it is transferred from a control off mode M12 to a constant speed control mode M14. At this time, the present vehicle speed Vs is set as a target vehicle speed for controlling running as a set vehicle speed Vm. When the present inter-vehicle distance D is smaller than the set inter-vehicle distance Dset, it is transferred from the control off mode W12 to a follow-up control mode M18. At this time, a value larger than the vehicle speed Vs at tansferring by (α) is set to be the target vehicle speed as the set vehicle speed Vm. Consequently, even in the case of the preceding vehicle being accelerated, acceleration tracking is possible and favorable tracking run can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In order to reduce the driving operation of an automobile, a constant-speed traveling device (such as a cruise control system) for performing a constant-speed traveling control has been put to practical use, and an inter-vehicle distance control device for performing a tracking traveling control of a preceding vehicle. Is being developed. For vehicles equipped with a constant-speed traveling device, when the set switch is set,
Even when the foot is released from the accelerator pedal, the vehicle runs while maintaining the set vehicle speed. The set vehicle speed can be changed by operating the operation switch, and is canceled when the driver steps on the brake pedal.

On the other hand, a vehicle provided with an inter-vehicle distance control device
When the set switch is pressed, the set inter-vehicle distance is calculated from the vehicle speed at that time, and the inter-vehicle distance with the preceding vehicle is detected by the inter-vehicle distance measuring device (camera, radar, etc.). By controlling the engine output and brakes to achieve the set inter-vehicle distance, the vehicle follows the preceding vehicle and runs.

[0004] By the way, during this pursuit running, the vehicle speed when the set switch is set is stored as the set vehicle speed, so that if the preceding vehicle accelerates above this set vehicle speed, the own vehicle will be accelerated. The vehicle speed is suppressed to the set vehicle speed, and does not follow the preceding vehicle.

[0005]

As described above, when the preceding vehicle accelerates at a speed equal to or higher than the set vehicle speed, if the preceding vehicle cannot be followed, it is difficult to perform good tracking. Further, when there is a following vehicle, it may bother the following vehicle and disrupt the traffic flow.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a traveling control device for a vehicle that can smoothly follow a preceding vehicle smoothly. In addition, when transitioning from tracking driving to constant speed driving
However, the vehicle's travel control device can
To provide a location.

[0007]

In order to achieve the above object, according to the present invention, an inter-vehicle distance measuring means for measuring an inter-vehicle distance with a preceding vehicle, and a preset inter-vehicle distance measuring means which is set in advance when the preceding vehicle is not captured. Constant-speed traveling control means for traveling at a set vehicle speed, and tracking traveling control for controlling the vehicle speed in a range of a set vehicle speed during tracking traveling so that the inter-vehicle distance measured when the preceding vehicle is captured is a predetermined distance. Means for outputting a start command signal for the tracking travel control and the constant speed travel control, and the start command signal for outputting a set vehicle speed during the constant speed travel. First vehicle speed setting means for setting the vehicle speed at the time of the vehicle, and second vehicle speed setting for setting the vehicle speed at the time of the tracking travel to a predetermined value larger than the vehicle speed at the time when the start command signal is output.
And a vehicle speed setting means, when the preceding vehicle at the time of the tracking travel control is lost, characterized in that at the vehicle speed setting according to prior Symbol second vehicle speed setting means performs the cruise control.

[0008]

According to the first aspect of the present invention, when the start command signal for the tracking drive control and the constant speed drive control is output by operating the operation switch, the set vehicle speed during the constant speed drive is changed to the start command signal. Is set to the vehicle speed at the time when is output, while the set vehicle speed during tracking is set to a predetermined value larger than the vehicle speed at the time when the start command signal is output, and when the preceding vehicle is lost during the tracking control , The constant speed traveling control is performed at the vehicle speed set by the second vehicle speed setting means. This makes it possible to smoothly and satisfactorily follow the preceding vehicle at the time of tracking, and even if the preceding vehicle is lost during the tracking control, the driving feeling is not deteriorated . Good running is ensured.

[0009]

FIG. 1 is a system configuration diagram of a travel control device. Hereinafter, the configuration of the travel control device will be described with reference to FIG. The travel control device is provided with a main control device (ECU) 2 that controls travel. On the input side of the ECU 2, a control power switch 11 for starting up the ECU 2, a CCD camera (not shown) provided at the front of the vehicle, and a scanning laser radar (not shown)
An inter-vehicle distance measuring device 12 for confirming the preceding vehicle and measuring the current inter-vehicle distance DS between the preceding vehicle and the own vehicle; a traveling lane recognition device 14 mainly comprising a CCD camera for confirming the traveling lane; An operation switch for inputting a vehicle speed indicator 16 for measuring the current vehicle speed VS, a start command and a release command for running control, an inter-vehicle time TC, a set vehicle speed Vm, etc., and a return operation to the set vehicle speed Vm, that is, a resume operation. 18, a throttle sensor, a wheel speed sensor,
Various sensor switches 2 such as a steering angle sensor and a warning switch (indicated by reference numeral 54 in FIG. 2)
0 is connected.

On the other hand, a throttle actuator 30, an automatic transmission (A / T) 32, a brake actuator 34 for operating a wheel brake (not shown), and the like are connected to the output side of the ECU 2,
These are operated based on an input signal from the input side. Further, on the output side of the ECU 2, an indicator 40 which is provided on an instrument panel (reference numeral 50 in FIG. 2) in front of the driver's seat and displays a driving control state is connected, and the driver can control the driving control state. It can be easily checked.

As shown in FIG. 1, the inside of the ECU 2 is divided into four processing units: an input processing unit 4, a control state calculation unit 6, a control content calculation unit 8, and a display content calculation unit 10. Inter-vehicle distance measurement device 12, traveling lane recognition device 14,
Input signals supplied from the vehicle speedometer 16, the operation switches 18, and the various sensor switches 20 are processed by the input processing unit 4 and the control state calculation unit 6 into output signals in the control content calculation unit 8 or the display content calculation unit 10. Is output. The control content calculation unit 8 outputs a drive signal to the throttle actuator 30, the A / T 32, and the brake actuator 34, and the display content calculation unit 10 outputs a display signal to the display 40.

FIG. 2 schematically shows the periphery of the instrument panel 50 in the driver's seat. As shown in the figure,
The instrument panel 50 includes the control power switch 11, the warning switch 54, the combination meter 60 having a function as the display 40, the center message display 41, and the like. The warning switch 54 is a switch for operating an inter-vehicle distance warning buzzer (not shown) for notifying by a warning sound that the preceding vehicle has approached and the current inter-vehicle distance DS has become small.

The lever-type operation switch 18 is provided on a steering wheel 56 extending from the lower part of the instrument panel 50 toward the driver. The operation switch 18 can perform an operation of increasing a set vehicle speed Vm and an operation of decreasing the inter-vehicle time TC by raising the operation, and input (set) a start command of the traveling control and a setting vehicle speed Vm described later by lowering the operation. Can be performed, the inter-vehicle time TC can be increased, and the resume operation can be performed. By operating the vehicle forward, a command to cancel the travel control can be input (canceled).

The combination meter 60 has, as display functions, a running control operation display lamp 62 for indicating whether or not the running control is being performed and a warning buzzer operating lamp 64 for indicating whether or not the inter-vehicle distance warning buzzer is operating.
Is provided. The center message display 41 has a set vehicle speed display section 42 for displaying the set vehicle speed Vm in a line drawing schematically showing the outline of the vehicle, and a current vehicle speed display section 42 between two arrows pointing away from each other. Inter-vehicle distance D
An inter-vehicle distance display unit 44 for displaying S, a preceding vehicle display unit 46 for displaying the presence or absence of a preceding vehicle by a line drawing schematically showing the outline of the rear part of the vehicle, and a warning lamp 48 are provided.
The set vehicle speed Vm displayed on the set vehicle speed display section 42 is limited to the set range (for example, 40 to 105 km / h).
The current inter-vehicle distance DS displayed on the inter-vehicle distance display section 44 is a predetermined distance D1 (for example, 99 m) required to be displayed.
Limited to:

FIG. 3 is a flowchart showing a control routine of the traveling control executed by the ECU 2. Hereinafter, the control outline of the traveling control device configured as described above will be described with reference to FIG. In step S10, the ignition O
After N, various internal values of the controller are initialized based on the system power being turned on. When step S10 ends, the process of the main routine that is repeated every fixed control cycle ts (for example, 26 msec) is performed. The processing of the main routine will be described below. In step S12, a timer for measuring the control cycle ts is reset.

In step S14, the inter-vehicle distance measuring device 1
2. Various input signals supplied from the traveling lane recognition device 14, the vehicle speedometer 16, the operation switch 18, and various sensor switches 20 are arithmetically processed. More specifically, a signal from the operation switch 18 is read, a vehicle speed VS is calculated, a throttle opening is calculated, a wheel speed is calculated, a steering angle is calculated,
Estimation calculation of the curvature (R) of the road, acquisition of image controller data from the CCD camera, and the like are performed.

In the next step S16, data of the preceding vehicle is calculated based on the signal from the scanning laser radar. Specifically, it is determined whether or not there is a candidate vehicle in the traveling lane, selection of a preceding vehicle when there is a candidate vehicle in the traveling lane, and the current inter-vehicle distance DS between the preceding vehicle and the own vehicle.
, The relative speed Vba between the preceding vehicle and the own vehicle, and the like, and an inter-vehicle distance alarm process for determining whether to sound an alarm based on the vehicle speed VS and the inter-vehicle distance DS.

In step S18, a failure diagnosis process for a CCD camera, a scanning laser radar, or the like is performed. Here, disturbance of the image signal from the CCD camera, contamination of the laser radar, and the like are detected and processed as a failure. In step S20, various control data setting processes are performed based on the result of the input signal processing performed in step S14 and the result of the calculation of the preceding vehicle data performed in step S16.

Here, first, the driver operates the operation switch 1.
8 to set the delay time from the preceding vehicle, that is, the inter-vehicle time TC, which is input. The inter-vehicle time TC is a value that can be changed according to the operation amount of the operation switch 18, and the value is, for example, 1.
It is set in the range of 5 sec to 2.5 sec. Then, the set inter-vehicle distance Dset between the own vehicle and the preceding vehicle is calculated based on the inter-vehicle time TC, and further, the safe inter-vehicle distances DSF1, DSF2
Is performed. The set inter-vehicle distance Dset is a threshold for determining whether or not the preceding vehicle is in a range in which tracking control described below is to be performed, and is set based on the map shown in FIG. As shown in the figure, the set inter-vehicle distance Dset is
The value varies depending on the inter-vehicle time TC, and the inter-vehicle time TC is in a range of a value XT1 (for example, 1.5 sec) to a value XT3 (for example, 2.5 sec). Set within the range. Usually, the set inter-vehicle distance Dset is such that the inter-vehicle time TC is a value XT2 (for example, 2.0 sec.
), That is, the values on the thick solid line in the figure are used as standard values.

The safe inter-vehicle distances DSF1 and DSF2 are used in control modes such as constant speed control, tracking control, gradual deceleration control, and deceleration control, which will be described later (see FIG. 4), to secure a sufficient inter-vehicle distance. This is a threshold value provided for the purpose. The safe inter-vehicle distance DSF1 is used during constant speed control and tracking control,
The value is set according to the vehicle speed VS at that time from the map 1 shown in FIG. 6 or the map 3 shown in FIG. These maps differ according to the inter-vehicle time TC, but here the case where the inter-vehicle time TC is a value XT2 (2.0 sec) is shown.

As shown in these figures, the safe inter-vehicle distance D
SF1 also varies depending on the relative speed Vba with the preceding vehicle,
When the relative speed Vba is equal to or less than zero (Vba ≦ 0 km), the value is the smallest when the relative speed Vba is zero (Vba = 0 km), and when the relative speed Vba is XV1 (for example, −10 km), XV2
(For example, −20 km), the size increases as the size decreases. That is, as the degree of approach of the preceding vehicle increases, the inter-vehicle distance DSF1 for maintaining safety increases. During tracking control, map 1 in FIG. 6 is used, and during constant speed control, map 3 in FIG. 8 is used. By distinguishing between the maps used for the constant speed control and the tracking control in this way, it is possible to suitably execute the traveling control according to the respectively assumed approach status. The thick solid line in the figure is the reference safe inter-vehicle distance DSF1 assumed in advance by experiments,
This is a reference threshold value when performing tracking control.

The safe inter-vehicle distance DSF2 is used for slow deceleration control and deceleration control, respectively, and its value is set in the same manner as in the case of the safe inter-vehicle distance DSF1 according to the vehicle speed VS at that time from the map 2 shown in FIG. Is done. The processing of steps S14 to S20 described above is performed by the input processing unit 4 of FIG.

In the next step S22, the set inter-vehicle distance Dset and the safe inter-vehicle distances DSF1, DSF obtained as described above are determined.
This is a step of performing control mode transition processing, that is, selecting a control mode, based on 2 and the current inter-vehicle distance DS.
This process is performed by the control state calculation unit 6. FIG.
FIG. 2 schematically shows each control mode and its transition. Hereinafter, each control mode and its transition will be described with reference to FIG.

Incidentally, the next step S24 is a set vehicle speed Vm which is executed by the control content calculating section 8 in performing the running control.
Step S26 includes various control output processes, that is, the throttle actuator 30, the A / T
32, a step of controlling each drive of the brake actuator 34. Since these steps are performed according to each control mode, they will be described together here.

As shown in FIG. 4, when the power is turned on and initialization is performed in step S10, the control mode is the initialization mode M10, and after the initialization process is completed, the control mode shifts to the control OFF mode M12. The control OFF mode M12 is a control mode when the traveling control is not performed and the normal driving operation by the driver is performed as described above.

When the travel control is started by operating the operation switch 18, the control mode to be shifted is determined based on the execution of steps S14, S16, and S20 described above. When the vehicle speed VS is within the controllable range (for example, 40 km / h ≦ VS ≦ 1
(05 km / h) and the current inter-vehicle distance DS is larger than the set inter-vehicle distance Dset obtained as described above, (D
S> Dset), and the mode transits to the constant speed control mode M14. At this time, the current vehicle speed VS is stored in the ECU 2 as the set vehicle speed Vm, and this value is set as the target vehicle speed Vt for performing the traveling control. (Vt = Vm = VS) In the constant speed control mode M14, the traveling control is performed so as to maintain the target vehicle speed Vt. In the constant speed control mode M14, the operation of the operation switch 18 causes the mode to temporarily shift to the speed adjustment mode M16 and set the vehicle speed Vm,
That is, the target vehicle speed Vt can be increased or decreased.

On the other hand, when the current inter-vehicle distance DS is less than or equal to the set inter-vehicle distance Dset (DS≤Dset), there is a preceding vehicle, and in this case, the control transits from the control OFF mode M12 to the tracking control mode M18. In the tracking control mode M18, the vehicle
The map 1 described above shows the distance between the vehicle and the preceding vehicle
Drive while keeping constant based on. Also at this time, the set vehicle speed Vm is stored based on the current vehicle speed VS, and this value is set as the target vehicle speed Vt for performing the traveling control. Is stored in the ECU 2 as the set vehicle speed Vm (Vm = Vm = 10 km / h).
VS + α). Therefore, when the preceding vehicle accelerates, acceleration tracking is possible within the range of α (10 km / h), and good tracking traveling can be performed. On the other hand, since the vehicle does not track the preceding vehicle beyond the set vehicle speed Vm, the vehicle does not excessively accelerate due to the sudden acceleration of the preceding vehicle.

In the tracking control mode M18, the inter-vehicle adjustment mode M20 is temporarily operated by operating the operation switch 18.
To the set inter-vehicle distance D by changing the inter-vehicle time TC.
It is possible to increase or decrease the set. When the traveling control is started, the inter-vehicle distance DS becomes the safe inter-vehicle distance DSF.
If it is smaller than 1, that is, if the own vehicle is too close to the preceding vehicle, the mode transits to the slow deceleration control mode M22. In the slow deceleration control mode M22, the control content calculation unit 8 of the ECU 2 controls the drive of the throttle actuator 30 to the closing side to lower the vehicle speed VS by the action of the engine brake. Thereby, the inter-vehicle distance with the preceding vehicle can be increased.

In the constant speed control mode M14, a preceding vehicle appears, and the inter-vehicle distance DS at that time is equal to the set inter-vehicle distance Dset.
If the following is satisfied (DS.ltoreq.Dset), the processing shifts to the tracking control mode M18. As described above, the constant speed control mode M1
4 uses the map 3 of FIG. 8, and the tracking control mode M18 uses the map 1 of FIG.

Constant speed control mode M14 and tracking control mode M
At 18, when the inter-vehicle distance DS becomes smaller than the safe inter-vehicle distance DSF1 (DS <DSF1), the control mode transits to the slow deceleration control mode M22. Slow deceleration control mode M22
When the inter-vehicle distance DS becomes sufficiently large and the current inter-vehicle distance DS becomes greater than or equal to the safe inter-vehicle distance DSF1 (DS ≧ DSF1), the process returns to the tracking control mode M18.

If the inter-vehicle distance DS does not increase and is still smaller than the safe inter-vehicle distance DSF2 due to the operation of the engine brake in the slow deceleration control mode M22, the mode shifts to the deceleration control mode M24. This deceleration control mode M2
In step 4, the A / T 32 is downshifted and the brake actuator 34 is driven and controlled, so that the vehicle speed VS
More rapidly.

FIG. 10 is a flowchart of a control routine for deceleration control executed by the ECU 2 in the deceleration control mode M24. Hereinafter, description will be given based on FIG. In step S40, it is determined whether or not the braking force FB is large. Here, the ECU 2 determines whether the vehicle speed VS or the relative speed V
The magnitude of the braking force FB is determined by comparing the required brake fluid pressure PN calculated based on ba with a predetermined threshold value P1 (for example, 1 MPa).

If the decision result in the step S40 is Yes (affirmative), and the necessary brake fluid pressure PN is equal to or more than the threshold value (1 MPa) (PN≥P1), the routine proceeds to a step S52, in which the brake actuator 34 is driven and brake control is performed. Do. On the other hand, the determination result of step S40 is No (No).
If the required brake fluid pressure PN is smaller than the threshold value (1 MPa), the routine proceeds to step S42, where the A / T 32 is downshifted. As a result, the engine braking force can be increased, and the vehicle speed VS can be satisfactorily reduced without driving and controlling the brake actuator 34. The frequency of use of the brake actuator 34 is reduced, and the deterioration of brake pads (not shown) is improved. And brake lights (not shown)
Overuse can be prevented. At this time, the timer is started, and the elapsed time tB since the shift down control is started
Time.

In step S44, it is determined whether or not the inter-vehicle distance DS is smaller than the safe inter-vehicle distance DSF3. The safe inter-vehicle distance DSF3 is determined from the map 5 in FIG. 9 according to the vehicle speed VS. In the case of this map 5 as well, as in the case of the safe inter-vehicle distances DSF1, DSF2, the relative speed V
The value differs depending on ba, and the value is relative speed V
When ba is zero (Vba = 0 km), the relative speed Vba is XV1 (for example, -10 km) and XV2 (for example, -2).
0 km) and XV3 (for example, -30 km).

If the decision result in the step S44 is No (negative)
In the case of, the process returns to step S42. On the other hand, step S
If the result of the determination at 44 is Yes (Yes) and the inter-vehicle distance DS is smaller than the safe inter-vehicle distance DSF3 (DS <DSF3), it is difficult to perform sufficient braking by the A / T32 downshift control alone. Therefore, step S46 is performed to further control the drive of the brake actuator 34.
Proceed to.

In step S46, the previous step S42
Then, it is determined whether or not the elapsed time tB at which time measurement was started is within the predetermined time tB1. Normally, the predetermined time tB1 is A / T3
The delay time from when the downshift control command is supplied to when the downshift is actually completed (for example, 1se
c) is set to Since the execution cycle of the control routine of the deceleration control is approximately 26 msec, this deceleration control is repeatedly executed until the elapsed time tB reaches the predetermined time tB1 (1 sec).

If the decision result in the step S46 is No (negative)
If the elapsed time tB has exceeded the predetermined time tB1 (1 sec), the process proceeds to step S48, where the brake control is performed by controlling the drive of the brake actuator 34 together with the shift-down control. On the other hand, step S
If the determination result at 46 is Yes (affirmative) and the elapsed time tB has not yet reached the predetermined time tB1 (1 sec), the process proceeds to step S50.

In step S50, the previous step S42
The shift-down control performed in step 1 is temporarily released. And
In the next step S52, the brake control is performed by controlling the drive of the brake actuator 34. Here, since the downshift control of the A / T 32 is stopped in step S50, only the brake control is performed. As described above, even if it is determined that the inter-vehicle distance DS is smaller than the safe inter-vehicle distance DSF3 by executing step S44 and that the brake control is necessary, the elapsed time tB is still the predetermined time t.
If B1 (1 sec) has not elapsed, that is, A / T32
If a downshift control command has been output to the user, but the downshift has not yet been performed, the downshift control is released so that no downshift is performed. As a result, even when the shift-down control and the brake control are performed together, the brake control is always started after the shift-down operation is completed, and the shift-down timing and the brake control start timing are synchronized. Do not overlap. Therefore, A / T3
The second shift shock and the brake shock caused by the operation of the brake actuator 34 do not occur at the same time, and the running feeling is not deteriorated.

When the traveling control is performed in the deceleration control mode M24 as described above, the inter-vehicle distance from the preceding vehicle can be increased in a short time. When the current inter-vehicle distance DS becomes equal to or greater than the safe inter-vehicle distance DSF2 (DS ≧ DSF2),
The process returns to the slow deceleration control mode M22. Tracking control mode M18
Or slow deceleration control mode M22 or deceleration control mode M24
When the preceding vehicle changes lanes during traveling control and stops suddenly from the front, that is, when the target is lost, the inter-vehicle distance DS is infinite (DS = ∞). In this case, The mode shifts to the vehicle speed holding mode M26.

In the vehicle speed holding mode M26, the vehicle speed VS when the preceding vehicle is lost is stored as the holding vehicle speed Vh, and the holding vehicle speed Vh is stored as the target vehicle speed Vt (Vt = Vh = V).
S), the target vehicle speed Vt is set to a predetermined time t2 (for example, 3se
c) is to be held. By the way, when the vehicle is running in the tracking control mode M18, the slow deceleration control mode M22, or the deceleration control mode M24, the throttle actuator 30, the A / T 32, and the brake actuator 34 are operating, and the vehicle accelerates and decelerates. Is being done. Therefore, as described above, if the vehicle speed VS at the time when the preceding vehicle is lost is set to the target vehicle speed Vt as it is, the vehicle speed VS that accelerates / decelerates does not suddenly reach the target vehicle speed Vt due to the action of the inertia force, and overshoot or An undershoot will occur.

Therefore, in the vehicle speed holding mode M26,
The target vehicle speed Vt is set according to the acceleration / deceleration of the vehicle. FIG. 11 shows a flowchart of a control routine of the vehicle speed holding control executed by the ECU 2,
Based on the figure, target vehicle speed V in vehicle speed holding mode M26
How to set t will be explained. In step S60, once
The target vehicle speed Vt is set to the vehicle speed VS at the time when the preceding vehicle is lost.

In step S62, it is determined whether or not the vehicle acceleration GS is within a predetermined range, and if it is outside the predetermined range, it is further determined whether the acceleration GS is larger or smaller than the predetermined range. The predetermined range is from the value GS1 (for example, -0.01G) to the value GS2.
(For example, 0.01 G). The acceleration GS is
It is calculated based on the vehicle speed VS. As a result of the determination in step S62, the acceleration GS becomes the value GS1 (for example, -0.01G).
And the value GS2 (for example, 0.01 G), the process proceeds to step S68.

Step S68 is a step of resetting the current vehicle speed VS to the target vehicle speed Vt. Here, the target vehicle speed Vt set in step S60, that is, the vehicle speed VS when the preceding vehicle is lost, is set as the target vehicle speed Vt as it is. If the result of determination in step S62 is that the acceleration GS is less than or equal to the value GS1 (-0.01 G) (GS ≤ GS1), that is, if the vehicle is decelerating and the vehicle speed VS undershoots, the next step Proceed to S64.

In step S64, this time, the acceleration GS
Is greater than the value GS1 (−0.01 G). If the determination result is No (No), the execution of step S64 is repeated. On the other hand, if the determination result is Yes (Yes) and it is determined that the acceleration GS has become larger than the value GS1 (-0.01G), the process proceeds to step S68.

Step S68 is a step of resetting the target vehicle speed Vt as described above. Here, the current vehicle speed VS is newly set as the target vehicle speed Vt. At this time, since the vehicle undershoots, the current vehicle speed VS is equal to the target vehicle speed Vt set in step S60.
And a vehicle speed VS smaller than the target vehicle speed Vt becomes a new target vehicle speed Vt.

If the result of determination in step S62 is that the acceleration GS is equal to or greater than the value GS2 (0.01 G) (GS ≥ GS2), that is, if the vehicle is accelerating and the vehicle speed VS is overshooting, then Proceed to step S66. In step S66, this time, the acceleration GS becomes the value GS2 (0.01
G) It is determined whether or not it has become smaller. The determination result is N
In the case of o (No), the execution of step S66 is repeated. On the other hand, if the determination result is Yes (affirmative) and it is determined that the acceleration GS has become smaller than the value GS2 (0.01 G), the process proceeds to step S68.

At this time, since the vehicle is overshooting, the current vehicle speed VS is higher than the target vehicle speed Vt set in step S60. Therefore, in step S68, the current vehicle speed VS is higher than the target vehicle speed Vt. Also sets the large vehicle speed VS as a new target vehicle speed Vt. FIG.
FIG. 2 is a diagram showing a time change of the vehicle speed VS when the above-mentioned vehicle speed holding control is performed while the vehicle is accelerating. As shown in the figure, for example, when a transition is made from the tracking control mode M18 to the vehicle speed holding mode M26, the vehicle speed VS is temporarily changed to the target vehicle speed V
t (shown by a dashed line), the vehicle speed VS is equal to the acceleration G
Overshoot with S. However, when the overshoot substantially reaches the peak and the acceleration GS falls within the predetermined range, the vehicle speed VS at that time is newly set to the target vehicle speed Vs.
reset to t.

As described above, when the vehicle shifts from the tracking control mode M18, the slow deceleration control mode M22, or the deceleration control mode M24 to the vehicle speed holding mode M26, the target vehicle speed Vt is set once, and then the target vehicle speed Vt is set according to the acceleration GS. Since the target vehicle speed Vt is set again, the vehicle speed VS changes smoothly, and the running feeling is not degraded, and good running can be obtained.

FIG. 13 shows, as a reference, the vehicle speed holding control, that is, the target vehicle speed Vt without resetting the target vehicle speed Vt.
Although the time change of the vehicle speed VS when t is set is shown, when the vehicle speed holding control is not performed, the vehicle speed VS returns to the target vehicle speed Vt after overshooting as shown in FIG. Therefore, the vehicle lacks running stability, and the running feeling is poor.

In the vehicle speed holding mode M26, a predetermined time t
After 2 (3 seconds), the process returns to the constant speed control mode M14. When returning from the vehicle speed holding mode M26 to the constant speed control mode M14, first, the vehicle travels while holding the vehicle speed VS at the time of loss, that is, the target vehicle speed Vt, which is the holding vehicle speed Vh, for a predetermined time t3 (for example, 30 seconds). Controlled. During this time, when the operation switch 18 is operated to resume, the set vehicle speed Vm set as described above is set.
Is returned. On the other hand, a predetermined time t3 (30 sec)
If the resume operation is not performed within
h is newly stored as the set vehicle speed Vm (Vm = Vt =
Vh = VS) Thereafter, the vehicle is controlled to run at the new set vehicle speed Vm.

FIG. 14 shows a time change of the vehicle speed VS which changes in accordance with the control mode which is changed as described above.
As shown in FIG.
8 starts the cruise control and sets the constant speed control mode M
At 14, the vehicle speed VSa is stored as the set vehicle speed Vm. At this time, the vehicle travels while maintaining the set vehicle speed Vm as the target vehicle speed Vt. When the vehicle transits from the constant speed control mode M14 to the tracking control mode M18 due to the approach of the preceding vehicle, the vehicle performs tracking according to the vehicle speed of the preceding vehicle.

Thereafter, when the preceding vehicle is lost and transits to the vehicle speed holding mode M26, the vehicle sets the holding vehicle speed Vh, which is the vehicle speed VSb at that time, as the target vehicle speed Vt for a predetermined time t2.
(3sec). Then, the predetermined time t2 (3
sec) After a lapse, the process returns to the constant speed control mode M14. Here, the vehicle continuously travels with the held vehicle speed Vh as the target vehicle speed Vt for a predetermined time t3 (30 seconds). When the predetermined time t3 (30 sec) has elapsed, the vehicle speed Vh, which is the vehicle speed VSb, is newly stored as the set vehicle speed Vm, and the vehicle travels using the set vehicle speed Vm as the new target vehicle speed Vt. On the other hand, when the resume operation is performed by operating the operation switch 18 within the predetermined time t3 (30 seconds), the target vehicle speed Vt becomes the initial set vehicle speed Vm as shown by a broken line in the figure.
That is, the vehicle speed becomes VSa, and the vehicle continues to run at the vehicle speed VSa.

As described above, when returning to the constant speed control mode M14, the grace period of the predetermined time t3 (30 seconds) is provided, and only when the resume operation is performed during this period, the vehicle speed returns to the initially set vehicle speed Vm. Thus, smooth and good running can be realized without feeling acceleration unintended by the driver. Step S22 to step S26
Is executed, step S28 is executed next. This step S28 is a step executed by the display content calculation unit 10, and performs various display and alarm output processing. As the output means, there are a lamp output, a display output, a buzzer output and a voice warning output. Specifically, the driving control operation display lamp 62, the warning buzzer operation lamp 64, the center message display 41 shown in FIG. There is an inter-vehicle distance warning buzzer (not shown) which issues a warning sound based on the inter-vehicle distance alarm processing function of the input processing unit 4 when the distance DS becomes smaller than the inter-vehicle distance for which the alarm is activated. The description of these display contents and the like is omitted here.

[0054]

As is apparent from the above description, claim 1
According to the vehicle travel control device, an inter-vehicle distance measuring unit that measures an inter-vehicle distance with a preceding vehicle, a constant speed traveling control unit that runs at a preset vehicle speed when the preceding vehicle is not captured, A tracking control unit that controls the vehicle speed in a range of a set vehicle speed during tracking so that a measured inter-vehicle distance becomes a predetermined distance when captured. An operation switch for outputting a start command signal for traveling control, first vehicle speed setting means for setting a set vehicle speed for constant speed traveling to a vehicle speed when the start command signal is output, and starting a set vehicle speed for tracking traveling when the command signal and a second vehicle speed setting means for setting a larger predetermined value than the vehicle speed at the time of output, the preceding vehicle is lost during tracking travel control is the set speed of the second vehicle speed setting means Since the high-speed traveling control is performed, the vehicle can smoothly and satisfactorily follow the preceding vehicle during the tracking traveling, and even if the preceding vehicle is lost during the tracking traveling control, the traveling feeling can be improved. without deterioration,
You can secure a good good traveling, can so as not to disturb the flow of traffic.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a travel control device.

FIG. 2 is a view showing the periphery of an instrument panel.

FIG. 3 is a flowchart illustrating a control routine of traveling control.

FIG. 4 is a diagram showing transition of each control mode.

FIG. 5 is a map showing a relationship between a set inter-vehicle distance DSET and a vehicle speed V;

FIG. 6 shows a safe inter-vehicle distance DSF used in tracking control.
4 is a map showing a relationship between 1 and a vehicle speed VS.

FIG. 7 shows a safe inter-vehicle distance D used during slow deceleration running control.
4 is a map showing a relationship between SF2 and vehicle speed VS.

FIG. 8 shows a safe inter-vehicle distance DSF used during constant-speed running control.
4 is a map showing a relationship between 1 and a vehicle speed VS.

FIG. 9 shows a safe inter-vehicle distance DSF used during deceleration driving control.
3 is a map showing the relationship between the vehicle speed Vs and the vehicle speed Vs.

FIG. 10 is a flowchart of a deceleration control routine executed during deceleration control.

FIG. 11 is a flowchart of a vehicle speed holding control routine executed at the time of vehicle speed holding control.

FIG. 12 is a diagram showing a time change of the vehicle speed VS when the vehicle speed holding control is performed during acceleration of the vehicle.

FIG. 13 is a reference diagram showing a time change of the vehicle speed VS when the vehicle speed holding control is not performed during acceleration of the vehicle.

FIG. 14 shows a vehicle speed V that changes according to a control mode to be changed.
FIG. 7 is a diagram showing a time change of S.

[Explanation of symbols]

 2 Main control unit (ECU) 4 Input processing unit 6 Control state calculation unit 8 Control content calculation unit 10 Display content calculation unit 11 Control power switch 12 Inter-vehicle distance measurement device 14 Traveling lane recognition device 16 Speedometer 18 Operation switch 20 Various sensor switches Class 30 Throttle actuator 32 Automatic transmission (A / T) 34 Brake actuator 40 Indicator

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takashi Kosaka 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (56) References JP-A-5-155270 (JP, A) JP-A-5-155270 JP-A-1-114550 (JP, A) JP-A-6-320983 (JP, A) JP-A-5-262164 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 31 / 00 F02D 29/02 301 G05D 13/62

Claims (1)

(57) [Claims] An inter-vehicle distance measuring means for measuring an inter-vehicle distance with a preceding vehicle; a constant-speed traveling control means for traveling at a preset vehicle speed when the preceding vehicle is not captured; A traveling control device for controlling a vehicle speed in a range of a set vehicle speed during the tracking traveling so that the measured inter-vehicle distance becomes a predetermined distance, wherein the tracking traveling control and the constant speed An operation switch for outputting a start command signal for traveling control; first vehicle speed setting means for setting a set vehicle speed at the time of the constant speed traveling to a vehicle speed when the start command signal is outputted; Second vehicle speed setting means for setting the vehicle speed to a predetermined value larger than the vehicle speed at the time when the start command signal is output, wherein the following vehicle is lost during the tracking travel control. Travel control device for a vehicle, characterized in that the setting speed according to the second vehicle speed setting means performs the cruise control.