JP2871246B2 - Travel control device for vehicles - Google Patents

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 control device for following a preceding vehicle so that a distance between the vehicle and the preceding vehicle becomes substantially constant.

[0002]

2. Description of the Related Art Conventionally, a traveling control device for automatically adjusting the speed of a vehicle has been developed for the purpose of reducing driving operation and improving safety on a highway.

[0003] In such a traveling control device, a constant speed traveling mode in which the driver cruises the vehicle at a preset vehicle speed, or when a preceding vehicle exists, the inter-vehicle distance to the preceding vehicle is maintained at a safe distance. A follow-up running mode for following the preceding vehicle while the vehicle is running is set.

Here, in the following running mode, vehicle speed control is performed so that the current inter-vehicle distance matches a predetermined or calculated target inter-vehicle distance based on the vehicle speed. For example, Japanese Unexamined Patent Publication No. 60-121130 discloses that a safe inter-vehicle distance (a target inter-vehicle distance) is calculated from a vehicle speed, and the safe inter-vehicle distance is corrected by a change amount of the inter-vehicle distance per a predetermined time, that is, a relative speed. A vehicular travel control device that controls a vehicle speed based on a difference between inter-vehicle distances is disclosed.

[0005]

However, the safe inter-vehicle distance (target inter-vehicle distance) is calculated based on the vehicle speed and the relative speed as described above, and the vehicle speed is uniquely determined so that the current inter-vehicle distance matches the target inter-vehicle distance. The control configuration has a problem that it does not always match the surrounding environment of the vehicle such as the degree of congestion on the road and the driving feeling of the driver.

That is, there are a case where the driver wants to maintain a substantially constant inter-vehicle distance with the preceding vehicle according to the surrounding environment, and a case where the driver emphasizes the speed rather than the inter-vehicle distance and wants to maintain the current speed. For example, when a slow vehicle such as a large truck is interrupted from the adjacent lane while following the preceding vehicle, in the conventional control device, deceleration is performed until the inter-vehicle distance with the interrupted vehicle becomes the safe inter-vehicle distance. However, when the road is crowded as described above, the inter-vehicle distance to the following vehicle is usually considerably short, and thus the inter-vehicle distance to the intervening vehicle is reduced to the safe inter-vehicle distance. In the control configuration, the distance between the vehicle and the following vehicle is rapidly reduced, and there is a problem that the driver feels uneasy. Usually, in such a case, the driver desires to travel at substantially the same speed as the interrupted vehicle and to travel along the traffic flow, rather than the inter-vehicle distance to the interrupted vehicle. However, the conventional cruise control device that only performs the following control does not reflect such a driver's operation feeling that emphasizes the vehicle speed, and there is a problem that it is not possible to perform a comfortable and safe following operation. .

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems in the related art, and has as its object to control the distance between the vehicle and the preceding vehicle and to follow the preceding vehicle in the following traveling mode, so as to follow the flow of traffic. Another object of the present invention is to realize a following operation that matches the driving feeling of the driver.

[0008]

In order to achieve the above object, according to the present invention, as shown in FIG. 1, an inter-vehicle distance detecting means 1 for detecting an inter-vehicle distance from a preceding vehicle, and detecting a speed of the own vehicle. A vehicle speed detecting means 2; a relative speed detecting means 3 for detecting a relative speed between the preceding vehicle and the own vehicle; a target inter-vehicle distance calculating means 4 for calculating a target inter-vehicle distance based on the speed of the own vehicle; And a control means for controlling the throttle so that the inter-vehicle distance becomes the target inter-vehicle distance. In the vehicle travel control device, the deceleration control of a predetermined value or more is performed by the control means 5 or the deceleration control is continued for a predetermined time or more. Deceleration state detection means 6 for detecting whether the distance between the vehicles is equal to or less than the target inter-vehicle distance and when the relative speed is positive. The deceleration control is stopped, and having a second control means 7 or the like for a predetermined time controlled throttle so that the relative speed is substantially zero and the preceding vehicle.

[0009]

The traveling control device for a vehicle according to the present invention has such a configuration, and gives priority to vehicle speed control over inter-vehicle control according to the history of deceleration control during follow-up traveling.

That is, for example, when a large-sized truck with a low speed is interrupted, the control means 5 performs deceleration control to increase the inter-vehicle distance. At this time, the deceleration control is performed at a predetermined value or more, or the vehicle is decelerated for a predetermined time or more. If the control is continued, it is determined that the vehicle has been decelerated more than necessary, and the deceleration control is stopped even if the inter-vehicle distance is equal to or less than the target inter-vehicle distance. The vehicle speed is controlled by the speed.

When excessive deceleration is performed as described above, the control is performed with emphasis on the vehicle speed rather than the vehicle-to-vehicle control. The vehicle can smoothly follow the vehicle.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a vehicle travel control device according to the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of this embodiment. Inter-vehicle distance sensor 10 as inter-vehicle distance detecting means
Is provided at the front of the vehicle. This inter-vehicle distance sensor 10
For example, a CCD camera, a radar device, a laser radar device, or the like that captures an image of a preceding vehicle can be used.
A vehicle speed sensor 12 that optically detects the rotation speed of the drive shaft of the vehicle is provided as vehicle speed detection means.

A setting switch 14 for setting the vehicle speed at the time of constant speed running is provided in the driver's seat, and a follow-up running system SW 16 is also provided in the driver's seat. Then, signals from each sensor and SW are supplied to the microcomputer 18.

The microcomputer 18 includes an input / output port, a ROM in which a processing program described later is stored, a CPU for performing an operation in accordance with the processing program, a RAM for storing the operation result, and the like. To control the running of the vehicle, and an alarm device 22 and a display device 24 provided in the driver's seat.
The driver is informed of the state of the following distance (for example, an alarm is issued in the case of the dangerous following distance) through the driver.

Hereinafter, the processing of the microcomputer 18 will be described in detail with reference to the flowchart of FIG. FIG. 3 shows a processing process in the following traveling mode in the present embodiment. First, it is determined whether the preceding vehicle is recognized (S100). This determination is based on the following distance sensor 1
It is determined whether or not finite data is output from 0 to finite data (when a laser radar device is used as an inter-vehicle distance sensor, finite data is output when a preceding vehicle exists at a distance of about 100 m or less). Is determined. If the preceding vehicle is being recognized, it is next determined whether or not the own vehicle is decelerating (S110). Here, the microcomputer 18 calculates a relative speed by calculating a time change amount of the inter-vehicle distance detected by the inter-vehicle distance sensor 10 during a predetermined time, and calculates the relative speed from the relative speed and the vehicle speed detected by the vehicle speed sensor 12. The target inter-vehicle distance LT is calculated. A known formula can be used as a calculation formula for calculating the target inter-vehicle distance LT,
In the present embodiment, two types of target inter-vehicle distances of near / far are calculated by the following equations.

LT = vehicle speed × 2.5−relative speed × 4 (near) LT = vehicle speed × 4−relative speed × 6 (far) Then, based on the difference between the target inter-vehicle distance LT and the current inter-vehicle distance L, the target vehicle speed is calculated. VT = VT = vehicle speed + G (L−LT)
(G: gain) to control the throttle actuator 20. Therefore, when the current inter-vehicle distance L is smaller than the target inter-vehicle distance LT, the target vehicle speed becomes lower than the current vehicle speed, and deceleration control (throttle front closing) is performed. Specifically, whether or not the deceleration control is being performed can be determined by calculating a time change of the vehicle speed detected by the vehicle speed sensor 12.

When the deceleration control is performed as described above, for example, when another vehicle such as a large truck is interrupted from the adjacent lane while following the preceding vehicle, the deceleration is set to the predetermined value ΔSP.
It is determined whether it is not less than D (S120). The predetermined value ΔSPD is stored in advance in the ROM, and when it is determined that the vehicle is decelerating, the predetermined value ΔSPD is read from the ROM and compared with the deceleration. When it is determined that the deceleration is relatively small and is equal to or less than the predetermined value ΔSPD,
Next, it is determined whether or not the duration of the deceleration control is equal to or longer than a predetermined time ΔT (S130). Specifically, when it is determined that the deceleration control is being performed, the timer is operated, and the timer elapsed time and the predetermined value ΔT stored and read in the ROM are read.
This is done by comparing The deceleration is a predetermined value ΔS
If it is not less than PD, or if the duration of the deceleration control is not less than the predetermined time ΔT, then it is determined whether or not the current inter-vehicle distance L is not more than the calculated target inter-vehicle distance LT (S140). . If it is shorter than the target inter-vehicle distance LT,
Further, it is determined whether or not the preceding vehicle is moving away, that is, whether or not the relative speed with respect to the preceding vehicle is positive (S15).
0). When it is determined that the inter-vehicle distance L to the preceding vehicle is less than or equal to the target inter-vehicle distance LT and that the preceding vehicle is moving away, the deceleration control is stopped even though the target inter-vehicle distance LT has not yet been reached (S160). ), The flag 1 is set to 1 (S170).

As described above, when the deceleration control is performed for a predetermined value or more, or is continuously performed for a predetermined time or more, and is less than the target inter-vehicle distance and is away from the preceding vehicle, the following By stopping the deceleration control in spite of the fact that the distance L has not yet reached the target inter-vehicle distance LT, it is possible to perform unnecessary deceleration and eliminate the risk of suddenly approaching the following vehicle. After stopping the deceleration in this way, the vehicle speed of the own vehicle is controlled according to the relative speed with respect to the preceding vehicle. That is, whether the preceding vehicle is decelerating,
That is, it is determined whether or not the relative speed is negative (S21).
0) When the preceding vehicle is decelerating, that is, when the inter-vehicle distance with the preceding vehicle is decreasing again, the inter-vehicle control (deceleration control) is performed again so that the inter-vehicle distance becomes the target inter-vehicle distance LT. (S400).

On the other hand, if the preceding vehicle is not decelerating, the vehicle accelerates to the speed of the preceding vehicle so that the relative speed with respect to the preceding vehicle becomes zero (S220). Continuously performs acceleration control so that the relative speed becomes 0 so as to follow the preceding vehicle (S230 to S260). Also, after accelerating to the speed of the preceding vehicle, if the preceding vehicle is not accelerating, that is, if it is running at the same vehicle speed, its own vehicle also keeps n seconds ( Vehicle speed control is performed to maintain the current vehicle speed (for example, for three seconds) (S240). Then, after n seconds, the flag 1 is set to 0, and the flag 2 is set to 1 (S250).

As described above, after the deceleration control is interrupted, the traveling state of the preceding vehicle is determined, and the traveling state of the preceding vehicle and the own vehicle are made the same traveling state, that is, the relative speed becomes substantially zero. By performing the vehicle speed control as described above, it becomes possible to quickly follow the preceding vehicle (in this case, the interrupted vehicle) as compared with the case where the vehicle speed control is uniquely performed so as to achieve the target inter-vehicle distance LT. It is possible to travel along the flow of the air.

After the vehicle speed control is performed so that the relative speed with respect to the preceding vehicle becomes 0, acceleration / deceleration control is performed until the target inter-vehicle distance LT is reached in order to shift to the original following running ( S310) If the target inter-vehicle distance LT has been reached, the flag 2 is set to 0 again, and the mode shifts again to the normal following travel mode.

FIG. 4 shows the time change of the vehicle speed and the inter-vehicle distance with the preceding vehicle when the above-described control in this embodiment is performed. FIG. 4 also shows the changes in vehicle speed and inter-vehicle distance by the conventional device with dotted lines for comparison. In the vehicle speed control by the conventional device, that is, in a configuration in which the vehicle speed is uniquely controlled such that the inter-vehicle distance with the preceding vehicle becomes the target inter-vehicle distance, when the preceding vehicle is recognized, the inter-vehicle distance with the preceding vehicle becomes the target inter-vehicle distance. The vehicle speed is controlled so as to match the target inter-vehicle distance.Therefore, there is a large difference between the vehicle speed of the preceding vehicle and that of the preceding vehicle. However, in the control according to the present embodiment, the deceleration is equal to or more than the predetermined value ΔSPD or the deceleration continuation time is short. If ΔT or more (0 indicates that both conditions are satisfied), deceleration is stopped even if the target inter-vehicle distance has not been reached, and thereafter the vehicle speed is controlled to match the vehicle speed of the preceding vehicle. By It is understood that the vehicle can follow the vehicle along the traffic flow.

As described above, in the present embodiment, the vehicle speed control is not uniquely performed so that the inter-vehicle or the like becomes the target inter-vehicle distance even when the inter-vehicle distance from the preceding vehicle becomes equal to or less than the target inter-vehicle distance. By stopping the deceleration control according to the deceleration situation and giving priority to the vehicle speed control so that the vehicle speed is almost the same as the vehicle speed of the preceding vehicle, it is possible to eliminate the risk of the following vehicle suddenly approaching and to smoothly follow the interrupting vehicle it can.

[0025]

As described above, according to the vehicle traveling control device of the present invention, even if another vehicle interrupts the vehicle following the preceding vehicle, unnecessary deceleration is performed and the following vehicle suddenly approaches. This makes it possible to eliminate the risk of running and to quickly follow the vehicle along the traffic flow.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of the present invention.

FIG. 2 is a configuration block diagram of one embodiment of the present invention.

FIG. 3 is a processing flowchart of an embodiment of the present invention.

FIG. 4 is a graph illustrating a time change of a vehicle speed and an inter-vehicle distance according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 inter-vehicle distance sensor 12 vehicle speed sensor 14 setting switch 16 system switch 18 microcomputer 20 throttle actuator

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60K 31/00-31/18 F02D 29/00-29/06 F02D 41/00-41/40

Claims (1)

(57) [Claims] An inter-vehicle distance detecting means for detecting an inter-vehicle distance from a preceding vehicle; a vehicle speed detecting means for detecting a speed of the own vehicle; a relative speed detecting means for detecting a relative speed between the preceding vehicle and the own vehicle; A vehicle travel control device, comprising: target inter-vehicle distance calculating means for calculating a target inter-vehicle distance based on the speed of the own vehicle; and control means for controlling a throttle so that the inter-vehicle distance with a preceding vehicle becomes the target inter-vehicle distance. A deceleration state detecting means for detecting whether a deceleration control equal to or more than a predetermined value has been performed by the control means or a deceleration control has been continued for a predetermined time or more; Is less than the target inter-vehicle distance and when the relative speed is positive, the deceleration control is stopped irrespective of the inter-vehicle distance, and the slot is set so that the relative speed with the preceding vehicle becomes substantially zero. The vehicular running control apparatus characterized by comprising a second control means for controlling the predetermined time, the.