JP3194279B2 - 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 while keeping a distance between the vehicle and the preceding vehicle substantially constant.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a vehicle traveling control device for automatically controlling the traveling of a vehicle for the purpose of reducing the driving operation of a driver on a highway or the like and improving safety. For example, in a vehicle traveling control device disclosed in Japanese Patent Application Laid-Open No. 60-215432, a safe inter-vehicle distance is calculated in accordance with the vehicle speed of the own vehicle, and when there is no preceding vehicle within the safe inter-vehicle distance, The driver controls the vehicle speed so that the vehicle speed is set in advance by the driver, and if a preceding vehicle exists within the safe inter-vehicle distance, the vehicle is accelerated or decelerated based on the inter-vehicle distance with the preceding vehicle to achieve the safe inter-vehicle distance. This is a configuration for controlling the traveling of the vehicle.

However, in such a configuration in which the acceleration / deceleration control is simply performed based on the inter-vehicle distance and the safe inter-vehicle distance, for example, if another vehicle cuts into the own lane from the adjacent lane while following the preceding vehicle, the vehicle should follow. Since the inter-vehicle distance with the preceding vehicle is rapidly reduced, there is a problem that sudden deceleration is performed to increase the inter-vehicle distance.

Therefore, for example, Japanese Patent Application Laid-Open No. Sho 60-131327
In the vehicle travel control device disclosed in the above publication, when another vehicle interrupts while following the preceding vehicle, the vehicle speed of the own vehicle is held for a predetermined time, and after a predetermined time has elapsed, the relative speed with the preceding vehicle is large, Therefore, a configuration has been proposed in which the vehicle speed holding state is continued when the interrupted vehicle moves away from the host vehicle. By maintaining the vehicle speed for a predetermined time in this manner,
For example, unnecessary acceleration / deceleration control in which the vehicle speed of the own vehicle is once reduced and then accelerated again when the interrupting vehicle moves away at a speed higher than the own vehicle speed can be eliminated.

[0005]

However, in such a configuration in which the vehicle speed of the own vehicle is uniformly maintained for a predetermined time when there is an interrupting vehicle, for example, even when the interrupting vehicle decelerates after the interrupt, the vehicle speed of the own vehicle may be reduced. , And the drivability is reduced, for example, the driver feels uneasy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to reduce drivability even if another vehicle interrupts the vehicle while following the preceding vehicle. An object of the present invention is to provide a traveling control device for a vehicle that can smoothly follow a preceding vehicle.

[0007]

In order to achieve the above object, the present invention relates to an inter-vehicle distance detecting means 1 for detecting an inter-vehicle distance to a preceding vehicle, as shown in FIG. Relative speed detecting means 2 for detecting the speed, vehicle speed detecting means 3 for detecting the speed of the own vehicle, and safe inter-vehicle distance calculating means 4 for calculating the safe inter-vehicle distance based on the speed of the own vehicle
Control means 5 for controlling a throttle or a brake on the basis of a magnitude relationship between the safe inter-vehicle distance and the inter-vehicle distance.
A vehicle travel control device having a minimum allowable inter-vehicle distance calculating means for calculating an allowable minimum inter-vehicle distance shorter than the safe inter-vehicle distance based on the relative speed and the speed of the host vehicle.
When the inter-vehicle distance is equal to or less than the allowable minimum inter-vehicle distance, the control means 5 controls the brake to decelerate, and the inter-vehicle distance is between the allowable minimum inter-vehicle distance and the safe inter-vehicle distance. In some cases, the control means 5 controls the throttle according to the relative speed to decelerate and maintain the vehicle speed.
It is characterized by being replaced .

[0008]

The traveling control device for a vehicle according to the present invention has such a configuration, and does not merely perform acceleration / deceleration control based on the magnitude relationship between the inter-vehicle distance and the safe inter-vehicle distance, but allows a shorter than the safe inter-vehicle distance. A physical quantity having a minimum inter-vehicle distance is newly introduced, and acceleration / deceleration control is performed based on the magnitude relationship between the inter-vehicle distance, the safe inter-vehicle distance, and the allowable minimum inter-vehicle distance. This allowable minimum inter-vehicle distance is defined as the minimum inter-vehicle distance that the driver can tolerate with the preceding vehicle. If the inter-vehicle distance becomes less than the allowable minimum inter-vehicle distance, the driver feels uneasy and operates the brake. Critical distance. If the inter-vehicle distance is equal to or longer than the allowable minimum inter-vehicle distance, the current vehicle speed may be maintained without decelerating immediately even if the inter-vehicle distance is equal to or less than the safe inter-vehicle distance.

Therefore, according to the present invention, when another vehicle interrupts, it is determined whether or not the inter-vehicle distance from the interrupted vehicle is less than the allowable minimum inter-vehicle distance. If the vehicle is longer than the minimum allowable inter-vehicle distance and the interrupted vehicle moves away, that is, if the relative speed is positive (above the threshold value), the throttle is controlled to maintain the current vehicle speed. In addition, when the interrupted vehicle approaches, that is, when the relative speed is negative (below the threshold value), the vehicle slowly decelerates by the throttle control to perform smooth following.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a traveling control device for a vehicle according to the present invention.

FIG. 2 is a block diagram showing the configuration of this embodiment. As an inter-vehicle distance detecting means, an inter-vehicle distance sensor 1
0 is provided at the front of the vehicle. As the inter-vehicle distance sensor, a CCD sensor, a scanning laser radar device,
Alternatively, a radar device using radio waves or the like can be used. Further, a vehicle speed sensor 12 that optically detects the rotation of the drive shaft is provided as vehicle speed detecting means.
Further, G is used as acceleration detecting means for detecting the acceleration of the vehicle.
A sensor 14 is provided. As the G sensor, for example, an acceleration sensor that utilizes the fact that the metal thin film gauge is deformed by an inertial force applied to a pendulum disposed near the center of gravity of the vehicle to change its resistance value can be used. Note that it is also possible to calculate the acceleration from a change in the vehicle speed obtained by the vehicle speed sensor 12 during a predetermined time without using the G sensor 14 as described above. Further, in this embodiment, in addition to these sensors, a yaw rate sensor 16 for detecting the yaw rate of the vehicle, a steering sensor 18 for detecting the steering angle of the vehicle, a throttle sensor 21 for detecting the throttle opening, and the like are respectively located at predetermined positions. Is provided. The detection signals from these sensors are input to an electronic control unit (hereinafter referred to as ECU) 20.

The ECU 20 includes an input / output interface, a ROM storing a processing program to be described later, a CPU for performing calculations in accordance with the processing program, a RAM for temporarily storing the calculation results, and the like. 24 to control the running of the vehicle, and sends a control signal to an alarm indicator 26 provided in the driver's seat to call the driver's attention. The operation of the ECU 20 is started by a main switch 28 provided near the driver's seat.
Similarly, a desired vehicle speed and inter-vehicle distance of the driver are set by a vehicle speed / inter-vehicle setting switch 30 provided near the driver's seat.

Hereinafter, the operation of the ECU 20 will be described in detail with reference to the flowchart of FIG. First, the ECU 20
Is determined based on the detection signal from the inter-vehicle distance sensor 10 as to whether or not the preceding vehicle is within the effective range. This determination can be made based on whether or not the inter-vehicle distance obtained by the inter-vehicle distance sensor 10 is a finite value. That is, for example, when a laser radar device is used as the inter-vehicle distance sensor 10, the effective distance measurement range is about 150 m, and when the preceding vehicle is at about 100 m, a finite value is obtained by the inter-vehicle distance sensor 10. Is output, and it is determined that the preceding vehicle is within the effective range (S101).

If YES is determined in S101, the flow shifts to the next S102 to calculate a safe inter-vehicle distance. The safety inter-vehicle distance S is defined by the following equation.

S = vehicle speed × 2.5−relative speed × 4 (near) S = vehicle speed × 4−relative speed × 6 (far) Here, which of far / near is adopted depends on the aforementioned vehicle speed / vehicle distance. It is determined by which mode of the far / near is set by the setting switch 30. Note that the safety inter-vehicle distance S is not calculated based on the relative speed as described above, and the preceding vehicle does not physically stop instantaneously. For example, S = (vehicle speed) ² /(2×0.7 × 9.8) can also be defined. The relative speed is obtained by calculating the time change of the following distance obtained by the following distance sensor 10 by the ECU.
The safe inter-vehicle distance S is also calculated by the inter-vehicle calculation means 20a in the ECU 20.

After the safe inter-vehicle distance S is calculated in this way, the process proceeds to the next S103, where the target vehicle speed T _v is calculated. The target vehicle speed T _v is calculated based on the vehicle speed and the error inter-vehicle distance E by T _v = vehicle speed + G × E. Here, G is a predetermined gain,
The error inter-vehicle distance E is a difference E = N−S between the inter-vehicle distance N and the safe inter-vehicle distance S. Specifically, it is calculated based on the vehicle speed detected by the vehicle speed sensor 12 input to the target vehicle speed calculating means 20c in the ECU 20 and the safe inter-vehicle distance S calculated by the inter-vehicle calculating means 20a. Then, thus calculated target vehicle speed T _v is inputted to the control arithmetic unit 20d in the ECU 20, the vehicle is the vehicle speed control so that the target vehicle speed T _v is performed.

In FIG. 4, the steps after S104 are steps showing the contents of the vehicle speed control. First, in S104, it is determined whether or not the current vehicle speed is within the vehicle speed maintenance region. FIG.
The vehicle speed maintenance region is indicated by reference symbol P. When the relative speed is approximately 0 (± 1 km / h) and the inter-vehicle distance is approximately the safe inter-vehicle distance (± 2 m), it is determined that the vehicle is within the vehicle speed maintenance region. , The current vehicle speed is maintained (S115). On the other hand, if the current vehicle speed is outside the vehicle speed maintenance region, it is determined in S105 whether the vehicle needs to accelerate. This determination is made using the above-mentioned error inter-vehicle distance E. If E is positive, it means that the inter-vehicle distance N is larger than the safe inter-vehicle distance S, so that the inter-vehicle distance with the preceding vehicle is reduced. It is determined that acceleration is necessary. On the other hand, if the error inter-vehicle distance E is negative, it means that the inter-vehicle distance N is smaller than the safe inter-vehicle distance S, so that it is determined that acceleration is unnecessary (deceleration is necessary in some cases).

The magnitude of this S105 in YES, that goes to S106 if the acceleration is determined to be necessary, set set by the vehicle speed-vehicle setting switch 30 speed T _s and the calculated target vehicle speed T _v A comparison is made. Then, the calculated target vehicle speed T _v If is smaller than the set vehicle speed T _s in order to match the vehicle speed to the target vehicle speed T _v, the acceleration by driving the throttle actuator 22. On the other hand, if the calculated target vehicle speed T _v is larger than the set vehicle speed T _s is replaced with the target vehicle speed T _v to set vehicle speed T _s shifts an upper limit on the S107 in order to this setting speed T _s, S1
At 09, the throttle actuator 22 is driven.

On the other hand, if no acceleration is required in S105, that is, if the following distance N is larger than the safe following distance S, control may be performed to maintain the present following distance. However, small control is performed. Frequent operation of the throttle or brake is not a favorable driving condition for the driver. In particular, when traveling with such a large inter-vehicle distance, there is a high possibility that the vehicle will be interrupted from the adjacent lane, and in this case, sudden braking must be performed uniformly in order to increase the inter-vehicle distance with the interrupted vehicle. This causes a problem that fuel efficiency is deteriorated. Therefore, even if there is such an interrupted vehicle, sudden braking is not applied depending on the relative speed with respect to the interrupted vehicle (particularly when the relative speed is positive and the interrupted vehicle moves away), and deceleration due to throttle operation or the like. It is desirable to be able to respond.

Therefore, in the present embodiment, a minimum allowable inter-vehicle distance D that the driver can tolerate, that is, does not require deceleration by the brake, is calculated in S110. For example, when the relative speed is positive (the preceding vehicle moves away from the own vehicle), the allowable minimum inter-vehicle distance D can be expressed as D = vehicle speed × 1−relative speed × 2, and the relative speed is negative (preceding vehicle). In the case where the vehicle approaches, D = vehicle speed × 1 + (relative speed) ² × 0.4. Specifically, the distance calculation means 20a in the ECU 20 calculates the distance based on the current vehicle speed detected by the vehicle speed sensor 12 and the relative speed calculated by the relative speed calculation means 20b. FIG. 3 is a graph showing the allowable minimum inter-vehicle distance calculated in this manner. In addition,
The horizontal axis in FIG. 3 represents the relative speed, and the vertical axis represents the inter-vehicle distance. Further, the allowable minimum inter-vehicle distance is indicated by a reference symbol D, and the above-mentioned safe inter-vehicle distance is indicated by a reference symbol S.

In this way, the allowable minimum inter-vehicle distance D is set, and whether or not a brake is necessary is determined by comparing the allowable minimum inter-vehicle distance D with the inter-vehicle distance N. That is, if the inter-vehicle distance N is smaller than the permissible minimum inter-vehicle distance D, the inter-vehicle distance is not an allowable inter-vehicle distance. Therefore, a signal is sent to the throttle actuator 22 to the brake actuator 24 to completely close the throttle, and the brake is applied to apply the target as much as possible to slow down and control T _v (step S112
To S113).

On the other hand, if the inter-vehicle distance N is larger than the allowable minimum inter-vehicle distance D, the flow shifts to S114 to evaluate the relative speed. This is because if the relative speed is equal to or higher than a certain level, the preceding vehicle naturally moves away even if the current vehicle speed is maintained, so the current vehicle speed only needs to be maintained, and if the relative speed is low, the throttle is released. This is because only deceleration by closing is performed and unnecessary braking is not performed. Therefore, in this S114, the relative speed and the predetermined threshold value (FIG. 3)
Then, the threshold value is compared with the threshold value R _{0. If} the relative speed is equal to or higher than the threshold value, throttle control is performed to maintain the current vehicle speed (S 11).
If the relative speed is smaller than the threshold value, the throttle is fully closed to reduce the speed (S116).
As described above, if the relative speed with respect to the preceding vehicle is equal to or greater than a certain value, the current vehicle speed is maintained. If the relative speed is less than that, the vehicle is decelerated only by the throttle, and the preceding vehicle enters the allowable minimum inter-vehicle distance D. In this case, the use of the brake for the first time enables smooth running control and also improves fuel efficiency. FIG. 3 shows the contents of the throttle control and the brake control described above.

As described above, in the present embodiment, a new physical quantity that is allowable by the driver, that is, a minimum allowable inter-vehicle distance that does not require deceleration by a brake is newly introduced, and the magnitude of the allowable minimum inter-vehicle distance and the inter-vehicle distance are increased. Since the comparison and the acceleration / deceleration control of the own vehicle are performed based on the magnitude relation of the relative speed,
Even if another vehicle interrupts the vehicle following the preceding vehicle, the current vehicle speed is maintained or deceleration is performed by fully closing the throttle according to the running state (inter-vehicle distance, relative speed) of the interrupted vehicle without immediately applying a sudden brake. It is possible to run smoothly.

[0024]

As described above, according to the vehicle travel control device of the present invention, even if another vehicle interrupts during the following vehicle following the preceding vehicle, the vehicle does not immediately perform the sudden braking. Good drivability can be obtained by smoothly following the interrupting vehicle.

[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 graph showing a safe inter-vehicle distance and an allowable minimum inter-vehicle distance according to the embodiment.

FIG. 4 is a processing flowchart of the embodiment.

[Explanation of symbols]

 Reference Signs List 10 inter-vehicle distance sensor 12 vehicle speed sensor 20 electronic control unit (ECU) 22 throttle actuator 24 brake actuator

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI B60T 7/12 B60T 7/12 C F02D 29/02 301 F02D 29/02 301C 301D 45/00 314 45/00 314M (58) Survey Field (Int.Cl. ⁷ , DB name) B60K 31/00 B60K 41 / 00,41 / 20 B60R 21/00 B60T 7/12 F02D 29/00-29/02 F02D 45/00

Claims (1)

(57) [Claims] An inter-vehicle distance detecting means for detecting an inter-vehicle distance from a preceding vehicle; a relative speed detecting means for detecting a relative speed with respect to a preceding vehicle; a vehicle speed detecting means for detecting a speed of the own vehicle; A safety inter-vehicle distance calculating means for calculating a safe inter-vehicle distance based on the speed of the vehicle, and a control means for controlling a throttle or a brake based on a magnitude relation between the safe inter-vehicle distance and the inter-vehicle distance. An allowable minimum inter-vehicle distance calculating means for calculating an allowable minimum inter-vehicle distance shorter than the safe inter-vehicle distance based on the relative speed and the speed of the own vehicle, and when the inter-vehicle distance is equal to or less than the allowable minimum inter-vehicle distance, The control means controls the brake to decelerate,
When the inter-vehicle distance is between the allowable minimum inter-vehicle distance and the safe inter-vehicle distance, the control means controls a throttle according to the relative speed to switch between deceleration and vehicle speed maintenance.
Vehicle control system, characterized in that that.