JP2654971B2 - Travel control device for vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a travel control device that controls a vehicle speed so as to maintain a predetermined inter-vehicle distance with respect to a preceding vehicle.

(Prior Art) The current road situation is following a worsening road, and the occurrence of vehicle congestion has become a daily occurrence. Running in such a traffic jam causes considerable pain to the driver, causes psychological frustration, and is one of the factors that cause a traffic accident. Therefore, in order to reduce the burden on the driver, an inter-vehicle distance control device has been proposed that controls the vehicle speed of the host vehicle using an ultrasonic sonar so as to maintain a constant safe inter-vehicle distance with respect to the vehicle in front. JP-A-60-163733).

By the way, when traveling at a low speed while maintaining a certain inter-vehicle distance with respect to the preceding vehicle, in a vehicle equipped with an automatic transmission, there is a creeping phenomenon due to the torque converter, so that the vehicle automatically follows the preceding vehicle only by brake control. It is possible to In this case, only the stop direction is controlled.
As long as the driver's attention is not reduced, safety is high.

However, in reality, there is a possibility that the driver's attention may be reduced, and a new problem occurs. For example, in a traffic jam, when entering the automatic driving mode by the front sonar and following the preceding vehicle while keeping a predetermined inter-vehicle distance, if the preceding vehicle is a large vehicle having a high vehicle height, the visibility of the upper front is blocked and the traffic light is blocked. Becomes invisible. For this reason, there is a possibility that the red light may enter the intersection where the light is on.

(Objects of the Invention) Accordingly, the present invention detects a large vehicle having a high vehicle height when the preceding vehicle is a large vehicle at the time of automatic tracking with a predetermined distance between the vehicles ahead, and increases the distance between the vehicles. Thus, an object of the present invention is to provide a vehicular travel control device that can safely and automatically follow a preceding vehicle while always maintaining good forward visibility.

(Constitution of the Invention) A traveling control device for a vehicle according to the present invention includes an identification means for identifying the height of a preceding vehicle, and a higher vehicle height in accordance with the height of the preceding vehicle identified by the identification means. Control means for controlling the vehicle speed so as to increase the inter-vehicle distance.

The identification means may include one of a plurality of distance detection means.
It is preferable to use one. And the control means includes:
The vehicle speed can be controlled such that a constant inter-vehicle distance adjusted according to the height of the preceding vehicle is maintained.

(Effects of the Invention) According to the present invention, when the preceding vehicle is a large vehicle having a high vehicle height, the inter-vehicle distance is changed so as to be longer, so that the vehicle follows the preceding vehicle while always maintaining good forward visibility. Since the traffic light can be overlooked, safety is improved.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration of a power train of a vehicle to which the present invention is applied, 1 is an engine, 2 is a throttle valve provided in an intake passage 3 thereof, and 4 is a drive mechanism of the throttle valve 2. Reference numeral 5 denotes an electronically controlled automatic transmission (EAT) attached to the rear end of the engine 1. The output of the transmission 5 is
The propeller shaft 6, the differential gear device 7, and the left and right drive shafts 8L and 8R transmit the power to the left and right drive wheels 9L and 9R, respectively. Brake devices 10L and 10R are attached to the drive wheels 9L and 9R, respectively.

On the other hand, the control unit 11
2. Based on the inputs from the shift lever 13 and the brake pedal 14, control the throttle opening, ignition timing and air-fuel ratio for the engine 1, and control the gear ratio for the EAT5 For the devices 10L and 10R, the braking force is controlled via the brake pressure servo unit 15, thereby automatically adapting the power train to the road surface condition and the driving according to the driver's will. I have. In the case of a four-wheel drive vehicle, the torque split of the front and rear wheels is also included in the control target. Also, as shown in FIG. 2, the present vehicle is provided with a front sonar 16 used at the time of traffic jam at the front of the vehicle body. After transmitting the sound wave pulse train forward, the transmission is switched to reception to receive a reflected wave (echo), and the inter-vehicle distance L is measured by the reflection time Tr.

L = Vs * Tr / 2 (Vs: vehicle speed) Then, the value Xf of the inter-vehicle distance to the preceding vehicle measured using the front sonar 16 is compared with a preset target inter-vehicle distance Xt, and the torque converter of the automatic transmission is used. By using the creeping phenomenon, the vehicle runs at a low speed without stepping on the accelerator pedal, and the braking force is controlled so that the inter-vehicle distance does not become shorter than the target inter-vehicle distance Xt.

Further, in addition to the front sonar 16, the vehicle includes an upper sonar 17 for transmitting an ultrasonic pulse train obliquely upward and forward as shown in FIG. 4, and an object is also detected by the upper sonar 17. If the difference between the inter-vehicle distance Xu measured by the upper sonar 17 and the inter-vehicle distance Xf measured by the front sonar 16 is smaller than a predetermined value, it is determined that the preceding vehicle is a large vehicle, and the target inter-vehicle distance Xt is determined. The value is changed to a large value, and the brake is operated so that the following distance Xf approaches the target following distance Xt.

FIG. 5 is a flowchart of the brake control executed by the control unit 11 described above. Control cycle is 100ms
And

First, initialization is performed in step S1, and 10 is performed in step S2.
After waiting for 0 ms, input signals from the accelerator pedal 12, the shift lever 13 and the brake pedal 14 are read in step S3, and in steps S4 to S6, the accelerator is turned off, the brake is turned off, and the shift position is determined. Makes a determination as to whether or not the vehicle is in the D range. If all of the determinations in steps S4 to S6 are "YES", the vehicle is running during creeping, so the inter-vehicle distance Xf is detected by the front sonar 16 in step S7. In the next step S8, the inter-vehicle distance Xu is detected by the upper sonar 17, and in step S9, a change ΔXf in the inter-vehicle distance Xf per unit time is calculated. Next, the target inter-vehicle distance Xt is set. In that case, step S10
To determine the absolute value | Xf−Xu | of the difference between the inter-vehicle distances Xf and Xu,
If f−Xu | <1 m, it is determined in step S11 that the vehicle is a large vehicle ahead of the vehicle, and the target inter-vehicle distance Xt is set to 10 m. Also |
If Xf−Xu | ≧ 1 m, it is determined that the vehicle is a normal vehicle that is a forward vehicle, and the target inter-vehicle distance Xt is set to 5 m in step S12. Next, calculation of the braking force F is performed. In this case, step
In S13, the following distance Xf is compared with the target following distance Xt, and Xf <Xt
If it is + 5m, the braking force F1 calculated by the following equation (1)
PD control of the braking force F is performed, and the process returns to step S2.

_{F1 = K P * (Xf-} Xt) + Kd * ΔXf + creeping driving force ... (1) where, K _P is a proportional control gain, Kd is a differential control gain.

If Xf ≧ Xt + 5m, the brake force F is set to zero in step S15, and the process returns to step S2.

In FIG. 5, | Xf−Xu | <1 in step S10.
If it is determined to be m, the process proceeds to step S11, in which the preceding vehicle is determined to be a large vehicle and the target inter-vehicle distance Xt is set to 10 m. Instead, as shown in FIG. 6, | Xf−Xu | <1m
In the case of, in step S11 'corresponding to step S11, it may be determined that visibility is obstructed, and the target inter-vehicle distance Xt may be selected to be equal to the inter-vehicle distance Xf detected by the front sonar 16 when visibility is obstructed. In that case, the above equation (1)
F1 = creeping driving force, and the vehicle stops with this braking force F1.

The above is the description of the configuration and the operation of the travel control device according to the present invention. As is clear from the above description, according to the present invention, even if the preceding vehicle to be automatically tracked is a large vehicle, the forward visibility can be reduced. Since a sufficiently large inter-vehicle distance can be secured, the safety of automatic driving during traffic congestion is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a power train of a vehicle to which the present invention is applied, FIG. 2 and FIG. 3 are explanatory views of a general method for measuring a distance between vehicles, and FIG. 4 is a distance between vehicles used in the apparatus of the present invention. FIG. 5 and FIG. 6 are explanatory diagrams of the measuring method, and the control flowchart thereof. 1 ... Engine 2 ... Throttle valve 4 ... Throttle valve drive mechanism 5 ... Electronically controlled automatic transmission (EAT) 10L, 10R ... Brake device 11 ... Control unit 15 ... Brake pressure servo unit 16 ... Front sonar, 17 ... Sonar upper

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Shinya 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (56) References JP-A-51-129274 (JP, A) JP-A-61 −24625 (JP, A)

Claims (3)

(57) [Claims] 1. A traveling control device for a vehicle, wherein a distance detecting means provided on a vehicle body detects an inter-vehicle distance to a preceding vehicle and controls a vehicle speed of the own vehicle based on the detection signal. Identification means for identifying the height of the vehicle, and control means for controlling the vehicle speed in accordance with the height of the preceding vehicle identified by the identification means so as to increase the inter-vehicle distance as the height of the vehicle increases. A travel control device for a vehicle. 2. A vehicular running system according to claim 1, wherein a plurality of said distance detecting means are provided, and one of said plurality of distance detecting means is used as an identification means for identifying the height of said preceding vehicle. Control device. 3. The vehicle running system according to claim 1, wherein said control means controls the vehicle speed such that a constant inter-vehicle distance adjusted in accordance with the height of the preceding vehicle is maintained. Control device.