JP3097360B2 - 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 cruise control device for a vehicle, and more particularly to a cruise control device for following a preceding vehicle.

[0002]

2. Description of the Related Art Conventionally, various devices have been developed and mounted for the purpose of reducing driver's driving operation and improving safety, and calculate a safe inter-vehicle distance from a running state of a vehicle. A traveling control device that controls the vehicle speed while following the preceding vehicle while maintaining the vehicle speed is one of them.

That is, the safe inter-vehicle distance (= target inter-vehicle distance) Ld is calculated from the own vehicle speed V. Ld = pV + q where p and q are calculated as constants, and the target driving force of the own vehicle required to reach the target inter-vehicle distance. F is calculated as follows: F = M {k1 (L-Ld) + k2 Vr} where M is the mass of the vehicle, L is the distance between vehicles, Vr is the relative speed, and k1 and k2 are calculated by the distance gain and the relative speed gain, respectively. Then, by comparing the target driving force with the running resistance FRES of the own vehicle, it is determined whether acceleration or deceleration is necessary, and the throttle actuator or the brake actuator is controlled to follow the preceding vehicle. Incidentally, the applicant of the present application has previously proposed such a travel control device in Japanese Patent Application No. 3-26463.

[0004]

Here, the target driving force F
The distance gain k1 and the relative speed gain k2 for calculating the distance are determined from the viewpoint of improving the tracking accuracy, and are set, for example, as (k1, k2) = (0.49, 0.64).

However, when the running of the own vehicle is controlled by the driving force that emphasizes the following accuracy, for example, when the preceding vehicle to be followed is decelerated by the brake when the target inter-vehicle distance has not yet been reached. However, since the control is performed with emphasis on the inter-vehicle distance rather than the relative speed, the brake control of the own vehicle tends to be delayed, and the driver does not match the actual driving sensation, and the driver may feel uneasy.

[0006] In view of such a possibility, the applicant of the present application has examined the actual driver's brake timing in detail, and as a result, by setting the relative speed gain of the target driving force F to be large, the actual driver's brake timing has been set. However, in a configuration in which the subject vehicle is simply controlled by the target driving force in which the relative speed gain is set to be large, the following sensitivity is sensitively affected by the movement of the preceding vehicle, but the following accuracy is deteriorated (the preceding vehicle). SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the related art, and has as its object the excellent tracking accuracy, and the brake timing can be reduced to the actual driving feeling. It is an object of the present invention to provide a vehicle driving control device that is more secure and conforms.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a travel control device for a vehicle that controls the speed of a vehicle based on the inter-vehicle distance and the relative speed with respect to a preceding vehicle and travels following the preceding vehicle. A vehicle speed detecting means for detecting an own vehicle speed; an inter-vehicle distance detecting means for detecting an inter-vehicle distance to a preceding vehicle; a relative speed detecting means for detecting a relative speed between the preceding vehicle and the own vehicle; A target inter-vehicle distance calculating means for calculating a target inter-vehicle distance; a first target driving force calculating means for calculating a first target driving force based on the inter-vehicle distance, the calculated target inter-vehicle distance and the relative speed; A second target driving force calculating means for calculating a second target driving force having a smaller inter-vehicle distance gain and a larger relative speed gain than the first target driving force based on the calculated target inter-vehicle distance and relative speed; , The first And having a control unit for controlling the vehicle acceleration means or a vehicle deceleration means based on target driving force and the second target driving force.

[0008]

As described above, in the present invention, in addition to the conventionally used first target driving force, a second target driving force that emphasizes relative speed, that is, a second target driving force with a small inter-vehicle distance gain and a large relative speed gain is newly calculated. The driving of the own vehicle is controlled using two driving forces, a first target driving force and a second target driving force. That is, in a normal following situation, the first target driving force is preferentially selected, and control is performed with emphasis on the following accuracy. In a situation where a relative speed is greatly changed such as when the preceding vehicle is decelerated by using a brake, the first target driving force is selected. The two target driving forces are preferentially selected, and control is performed with emphasis on relative speed.

[0009]

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. 1 is a block diagram showing the configuration of this embodiment. A vehicle speed sensor 10 and an inter-vehicle distance sensor 12 are respectively mounted at predetermined positions of the vehicle. In addition, as the inter-vehicle distance sensor 12, a laser radar device, a millimeter wave radar device, or the like can be used. The own-vehicle speed data V detected by the vehicle speed sensor 10 and the inter-vehicle distance data L with respect to the preceding vehicle detected by the inter-vehicle distance sensor 12 are based on the following electronic control unit E.
It is supplied to the CU 14. The ECU 14 includes an I / O interface for inputting and outputting data from sensors, a CPU for performing calculations, a memory for storing calculation results and gains used for the calculations, and performs the following calculations to transmit control signals to the throttle actuator. 16 to the brake actuator 18.

The arithmetic processing performed by the ECU 14 is as follows: (1) Differential calculation of the inter-vehicle distance data L supplied from the inter-vehicle distance sensor 132 to calculate a relative speed Vr with respect to the preceding vehicle. Based on the target inter-vehicle distance Ld, Ld = pV +
(3) The running resistance FRES is calculated from the map stored in the memory based on the own vehicle speed V. (4) The inter-vehicle distance L, the target inter-vehicle distance Ld, and the relative speed V
Calculate the first target driving force F1 based on r. (5) Inter-vehicle distance L, target inter-vehicle distance Ld, and relative speed V
The second target driving force F2 is calculated based on r. (6) The magnitudes of the first target driving force F1, the second target driving force F2, and the running resistance FRES are compared. In this embodiment, the first target driving force F2 is calculated. When calculating the force F1 (inter-vehicle distance gain k1, relative speed gain k2
) = (0.49,0.64), and (k1, k2) = (0.10,0.80) for calculating the second target driving force F2. The value (0.10, 0.80) when calculating the second target driving force F2 is a numerical value obtained as a result of a detailed study of the actual driver's brake timing by the applicant of the present invention as described above. Is used, control is performed which is in good agreement with the driver's brake timing.

FIG. 2 shows the relationship between the first target driving force F1, the second target driving force F2, and the running resistance FRES in this embodiment. The horizontal axis is the second target driving force F2, and the vertical axis perpendicular to it is the first target driving force F1, and the origin, which is the intersection of both axes, indicates the running resistance FRES. Conventionally, the acceleration / deceleration control is performed only by comparing the magnitude of the first target driving force F1 with the running resistance FRES. Therefore, even in the region II where the brake should be operated to decelerate, F1> FRES
Therefore, the brake control was not performed. In this embodiment, not only the magnitude comparison between F1 and FRES, but also F2 and FRES that reflect the actual driver's braking timing
By controlling the size of the vehicle, the traveling of the vehicle is controlled. That is, in FIG. 2, in the conventional control, regions I, II: acceleration (throttle opening control), regions III, IV: deceleration (brake ON control), but in the present embodiment, region I: acceleration (throttle opening control) Region II: deceleration in F2 Regions III and IV: deceleration in F1 and control by appropriately switching between F1 and F2.

Hereinafter, EC will be described with reference to the flowchart of FIG.
The operation of U14 will be described in more detail. First, the first target driving force F1 and the second target driving force F2 are calculated based on the inter-vehicle distance L, the calculated target inter-vehicle distance Ld, and the relative speed using the respective inter-vehicle distance gain k1 and relative speed gain k2 ( S101). Next, the running resistance FRES is calculated from the vehicle speed V using a map (S102). And
The magnitudes of F1 and FRES are compared (S103). F1 ≧
If it is FRES, a comparison is made between F2 and FRES (S104). If F2 ≥ FRES, then
This is a driving situation corresponding to the region I of FIG. 2, and therefore, it is necessary to accelerate.
Is set to 0 (S105), and the target driving force F1 is set.
Is calculated from the map (S113-S116). Then, the actuator is controlled so that the throttle opening is attained, thereby controlling the acceleration of the own vehicle (S108).

On the other hand, F1 ≧ FRES, but F2 <FRES
If, for example, the inter-vehicle distance is longer than the target inter-vehicle distance but the preceding vehicle is decelerated using the brake, etc., after setting the flag FLAG to 1 (S106),
The target driving force Fd is set to F2 (S107), and (Fd
-FRES) is calculated from the map using the target hydraulic pressure P of the brake actuator (S112). Then, the throttle opening is set to 0 (S115), and S112
Brake control and deceleration with the target oil pressure P calculated in (S)
116). At this time, since the brake control is performed with the second target driving force F2, the deceleration control is performed at a timing that matches the actual driver's brake timing.
The reason why the flag FLAG is once set from 0 to 1 in S106 will be described later.

When F1 <FRES, the value of the flag FLAG is determined (S108), and FLAG = 0.
, The target driving force Fd is set to F1 (S11).
1) The target hydraulic pressure P of the brake actuator for realizing (Fd-FRES) is calculated from the map (S112).
Then, the throttle opening is set to 0 (S11).
5) The brake is controlled by the target oil pressure P calculated in S112 to decelerate (S116).

On the other hand, when the flag FLAG = 1, F1.gtoreq.FRES and F2 <FRES until the previous control, and the deceleration control is performed with the target hydraulic pressure P of the brake actuator realizing (F2 -FRES). It means that it was. Therefore, if the control is immediately performed with the target hydraulic pressure P of the brake actuator realizing (F1 -FRES),
In the case of F1 <F2, the target oil pressure P temporarily drops to near zero, causing a "brake loss feeling" and giving the driver a feeling of strangeness or fear. Therefore, in order to prevent such a "brake loss feeling" at the time of control switching, in this embodiment, the value of FLAG is determined. If FLAG = 1, then F1 and Fd
(That is, F1 and F2) are compared (S10
9) When F1 <Fd, the previous deceleration control is continued (S112). When F1 ≧ Fd, FLAG is set to 0 for the first time (S110), and F1 is set as the target driving force Fd (S111). ), The deceleration control is performed with the target hydraulic pressure P of the brake actuator realizing (F1 -FRES) (S112). Note that the control cycle in this embodiment is 32 ms.

The acceleration / deceleration control in the present embodiment is summarized as follows.

(A) Throttle control (1) When F1 ≧ FRES and F2 ≧ FRES Target throttle opening = throttle opening realizing F1 (2) In cases other than (1), target throttle opening = 0 (B) Brake control (1) When F1 <FRES, hydraulic pressure that achieves target brake hydraulic pressure = (F1-FRES) (2) When not (1) and when F2 <FRES, hydraulic pressure that achieves target brake hydraulic pressure = (F2-FRES) (3) When not (1) and not (2) Target brake oil pressure = 0 As described above, in the present embodiment, the first target driving force F1 and the second target driving force F2 are appropriately set according to the traveling situation. In addition to switching and controlling, it is possible to prevent a feeling of a brake slippage at the time of switching and to perform a following running with no delay in brake timing and excellent in following accuracy.

In a vehicle equipped with a diesel engine, acceleration / deceleration control may be performed by controlling the fuel injection amount.

[0020]

As described above, according to the vehicle traveling control device of the present invention, it is possible to follow the vehicle with high tracking accuracy and brake timing that matches the actual driving feeling and with higher safety. Becomes

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of switching of a target driving force according to the embodiment.

FIG. 3 is a processing flowchart of the embodiment.

[Explanation of symbols]

 Reference Signs List 10 vehicle speed sensor 12 inter-vehicle distance sensor 14 ECU 16 throttle actuator 18 brake actuator

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G08G 1/16 B60K 31/00 F02D 29/02 301

Claims (1)

(57) [Claims] 1. A traveling control device for a vehicle that controls own vehicle speed based on an inter-vehicle distance and a relative speed with a preceding vehicle, and that follows the preceding vehicle, comprising: vehicle speed detecting means for detecting the own vehicle speed; An inter-vehicle distance detecting means for detecting an inter-vehicle distance of the vehicle; a relative speed detecting means for detecting a relative speed between the preceding vehicle and the own vehicle; a target inter-vehicle distance calculating means for calculating a target inter-vehicle distance based on the own vehicle speed; First target driving force calculating means for calculating a first target driving force based on the distance, the calculated target inter-vehicle distance and the relative speed; and the first target driving force calculating means based on the inter-vehicle distance, the calculated target inter-vehicle distance and the relative speed. Second target driving force calculating means for calculating a second target driving force having a smaller inter-vehicle distance gain and a larger relative speed gain than the target driving force of the first and second target driving forces, and the first target driving force and the second target driving force. Vehicle Vehicle control system, characterized in that it comprises a control means for controlling the means or vehicle deceleration means.