JPH068747A - Speed control device for vehicle - Google Patents

Abstract

PURPOSE:To perform optimum acceleration at the time of another vehicle passing by providing a means which determines a target speed based on a corrected target car speed and a present car speed during safety where a target intervehicle distance is lower than a present intervehicle distance and controls an engine output regulating means. CONSTITUTION:Since when a target intervehicle distance is higher than a present intervehicle distance, a risk state where an own car after change of a lane too approaching a preceding car is produced, a target deceleration is determined based on the target intervehicle distance and the present intervehicle distance and a brake force regulating means 6 is controlled by a control means 10. When the target intervehicle distance is lower than the present intervehicle distance, an intervehicle distance between an own car and a preceding car after the change of a lane is a safe distance, target acceleration is determined based on a corrected target car speed and a present car speed and acceleration is executed in a way that an engine output regulating means 5 is controlled by the control means 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed control device, and more particularly to a vehicle speed control device for controlling a vehicle-to-vehicle distance between a vehicle and a vehicle in front (hereinafter referred to as a front vehicle). .

[0002]

2. Description of the Related Art Conventionally, a constant speed that automatically adjusts the opening of a throttle valve as an engine output adjusting means so that the speed of a vehicle can be kept constant even if a driver does not operate an accelerator pedal. Vehicles equipped with a traveling device (auto cruise) are becoming popular.

In such a constant-speed traveling device, there is a possibility of a rear-end collision with the preceding vehicle due to traffic congestion on the road. In order to prevent such a rear-end collision, the vehicle-interval distance with the preceding vehicle is detected and a predetermined safe inter-vehicle distance is set. Keeping devices have been developed.

In Japanese Patent Laid-Open No. 55-86000, which is one example thereof, the safe inter-vehicle distance is calculated according to the set vehicle speed of the own vehicle, and the inter-vehicle distance with the preceding vehicle is calculated. If the front vehicle does not exist within the safe inter-vehicle distance, constant speed traveling control is performed.If the front vehicle exists within the safe inter-vehicle distance, on the other hand, it is dangerous and the throttle valve opening is set. It is controlled so that the safe inter-vehicle distance can be maintained by decreasing the distance.

Further, in Japanese Patent Laid-Open No. 60-121130, the inter-vehicle distance between the own vehicle and the front vehicle is constantly detected, and according to the change in the inter-vehicle distance (change in relative speed between the own vehicle and the front vehicle). According to the above), the safe inter-vehicle distance corresponding to the vehicle speed of the host vehicle is corrected, and the vehicle speed is controlled according to the difference between the safe inter-vehicle distance and the actual inter-vehicle distance.

[0006]

Generally, when the front vehicle is slower than the set speed of the host vehicle, the vehicle keeps the distance between the front vehicle and the vehicle at the vehicle speed of the front vehicle, but the vehicle travels around the highway. It is common to want to make an overtaking when the road conditions are vacant, but in the conventional technology as described above, when making an overtaking, (1) stepping on the accelerator by yourself, ) Because the lane was changed and the vehicle moved to the outside of the distance measuring range of the inter-vehicle distance detecting means such as laser radar, the speed was automatically increased to the set speed.
In the case of (1), the easy drive performance is impaired, (2)
In the case of, there is a problem that not only the acceleration is delayed, but also the acceleration rate becomes so small as to be unsuitable for the overtaking operation.

Therefore, it is an object of the present invention to realize a vehicle speed control device capable of maintaining an inter-vehicle distance control and performing an optimum acceleration when overtaking.

[0008]

In order to achieve the above object, a vehicle speed control device according to the present invention detects an inter-vehicle distance between a front vehicle and an own vehicle, as conceptually shown in FIG. Means 1, vehicle speed detecting means 2, target vehicle speed setting means 3, means 4 for confirming lane change, engine output adjusting means 5,
When the lane change at the time of overtaking is confirmed while the target vehicle speed is set by the braking force adjusting means 6 and the target vehicle speed setting means 3, the target vehicle speed is corrected and the target inter-vehicle distance is obtained from the current vehicle speed. Further, when the target inter-vehicle distance is greater than the current inter-vehicle distance, a target deceleration is obtained based on the target inter-vehicle distance and the current inter-vehicle distance, and the braking force adjusting means 6 is controlled so that the target inter-vehicle distance is equal to the current inter-vehicle distance. When the vehicle is safer than the inter-vehicle distance, a means 10 for controlling the engine output adjusting means 5 by obtaining a target acceleration based on the corrected target vehicle speed and the current vehicle speed is provided.

[0009]

In the vehicle speed control apparatus shown in FIG. 1, the control means 10 first sets the target vehicle speed by the target vehicle speed setting means 3 in the constant speed traveling state and outputs the signal from the lane change confirming means 4 when overtaking. It is determined whether or not the lane change is confirmed, and when the lane change is confirmed, the target vehicle speed is corrected.

Further, the control means 10 obtains the target inter-vehicle distance by the current vehicle speed detected by the vehicle speed detecting means 2 at the time of such lane change, and the inter-vehicle distance detecting means 1 detects the obtained target inter-vehicle distance. It is determined whether it is greater than the current inter-vehicle distance.

As a result of this judgment, when the target inter-vehicle distance is larger than the current inter-vehicle distance, it is in a dangerous state that the own vehicle after the lane change is too close to the front vehicle. Therefore, based on the target inter-vehicle distance and the current inter-vehicle distance. Then, the target deceleration is obtained to control the braking force adjusting means 6.

When the target inter-vehicle distance is smaller than the current inter-vehicle distance, the inter-vehicle distance with the preceding vehicle after the lane change is a safe distance. Therefore, based on the target vehicle speed corrected as described above and the current vehicle speed. Acceleration is performed by obtaining the target acceleration and controlling the engine output adjusting means 5.

In this way, the driver's intention to overtake is confirmed, and appropriate acceleration is performed so that the speed becomes equal to or higher than the set vehicle speed only during overtaking.

[0014]

FIG. 2 shows an embodiment of a vehicle speed control device according to the present invention. In this embodiment, a radar device is used as the inter-vehicle distance detecting means 1 shown in FIG. A vehicle speed sensor is used as 2, and target vehicle speed setting means 3
As the lane change confirmation means 4, a combination of a winker switch 4a and a steering angle sensor 4b is used.

A throttle valve actuator connected to a throttle valve (not shown) is used as the engine output adjusting means 5, and a pressure control connected to a wheel cylinder (not shown) as the braking force adjusting means 6. It uses a valve.

Further, a controller composed of a microcomputer is used as the control means 10, and the controller 10 is connected to the radar device 1, the sensors 2 and 4b and the switches 3 and 4a, and an input port for inputting these output signals. 10a, a CPU 10b that processes an output signal from the input port 10a, a ROM 10c that stores a control program executed by the CPU 10b, and a CPU
A RAM 10d for randomly accessing data read / write in the process of performing arithmetic operation by 10b, and an output port 10e for outputting a signal processed by the CPU 10b and giving it to the motor drive circuit 12 or the D / A converter 13. Has been done.

An A / D converter 11 is provided between the controller 10 and the vehicle speed sensors 2, 4b, a motor drive circuit 12 is provided between the controller 10 and the throttle valve actuator 5, and a pressure control valve 6 is provided. A D / A converter 13 is provided between them.

Reference numeral 7 is a brake pedal switch, and 8 is a clutch switch. These switches 7 and 8 are connected to the input port 10a of the controller 10 so as to function as elements for releasing control. It has become.

Controller 1 in such an embodiment
A control program executed at 0 is shown in FIGS. 3 and 4, and the operation of the embodiment shown in FIG. 2 will be described below with reference to this control program.

First, in the present invention, the auto-cruise set switch 3 is provided on the premise that auto-cruise (constant speed running) is performed, and it is determined whether or not the switch 3 is turned on (step S1). ). As a result, this control program is terminated when the set switch 3 is OFF.

When it is determined in step S1 that the set switch 3 is ON (during constant speed traveling), it is determined whether or not the releasing operation is performed (step S2). This can be determined by whether the brake pedal switch 7 or the clutch switch 8 shown in FIG. 2 is ON, and either of these switches 7 and 8 is ON.
At the time of, this control program is terminated.

When it is found in step S2 that the releasing operation has not been performed, the target vehicle speed V _t when the auto cruise set switch 3 is set is read from the output of the vehicle speed sensor 2 and set (step S3). . The setting of the target vehicle speed V _t is carried out only when the auto-cruise set switch 3 has been set, then does not change.

Then, the inter-vehicle distance D from the preceding vehicle is read from the output signal of the radar device 1 (step S4), and the current vehicle speed V is read from the vehicle speed sensor 2 via the A / D converter 11 (step S5). ).

Next, confirm the lane change when overtaking
U This is the output signal of the winker switch 4a.
A turn signal (not shown) is directed to the right from
It is determined whether or not (step S6), the winker switch
When it is found that the chi 4a is not pointing to the right
Target vehicle distance D from vehicle speed V read in step S5 _t
Is calculated (step S7). This is the vehicle speed V as shown
By using constants A and B for_t= AV + B
It is calculated from

Then, the target inter-vehicle distance D _t obtained in step S7 is compared with the current inter-vehicle distance D read in step S4 (step S8). When D _t > D, the target inter-vehicle distance is shorter than the actual inter-vehicle distance. Since the distance from the preceding vehicle is too short and the vehicle is in a dangerous state, it is necessary to decelerate the vehicle to maintain the target inter-vehicle distance, and the deceleration α at this time is calculated (step S9). This arithmetic expression is a linear function relating to D _t −D as shown in the figure, and the constants K1 and L1
By using and, α = K1 × (D _t −D) + L1
It can be obtained by the formula. The constants K1 and L1 are selected so that α takes a negative value in this case.

On the other hand, when it is found in step S8 that D _t > D is not satisfied, the inter-vehicle distance is in a safe state. At this time, therefore, the acceleration α for accelerating the vehicle is calculated in order to reach the target vehicle speed. Yes (step S1
0). The calculation formula at this time also uses constants K2 and L2 as shown in the figure. The difference between the target vehicle speed V _t and the actual vehicle speed V is multiplied by a constant K2, and the constant L2 is added to this to obtain α = K2 × (V _t -V)
It can be calculated by the formula + L2.

In this way, based on the acceleration / deceleration α obtained in step S9 or S10, the operation amount for the throttle valve actuator 5 shown in FIG. 2 is calculated in the case of acceleration, and the pressure control valve in the case of deceleration. The operation amount for 6 is calculated.

The operation amount is obtained by obtaining the throttle operation amount Δθ or the brake operation amount ΔP from, for example, a memory map when the acceleration / deceleration α is plotted on the horizontal axis as shown in FIG. In the case of the example, when the deceleration is small, the throttle operation amount Δθ is adjusted instead of the brake operation amount ΔP to substantially generate the brake operation amount.

The throttle operation amount Δθ thus obtained from FIG. 5 is applied to the motor drive circuit 12, or the brake operation amount ΔP is supplied via the D / A converter 13 to the pressure control valve 6.
Acceleration control or deceleration control can be performed by each of the above, and speed control can be executed (step S12).

Returning to step S6, when it is found that the winker switch 4a is directed to the right, this time the output signal from the steering angle sensor 4b is input via the A / D converter 11. The CPU 10b of the controller 10 determines whether or not the steering angle θ at this time is larger than a constant value θ _{0 at} which it can be determined that a lane change has been performed (step S13), and when the constant angle θ ₀ is not exceeded, , Step S as above
7. If not, go to step S shown in FIG.
Proceed to 14.

In step S14 of FIG. 4, the target vehicle speed V _T set in step S3 is corrected. The formula for the correction at this time is shown in the figure. This V _T is represented by aV _t , and the constant a at this time is larger than 1, so the corrected target vehicle speed V _T is the set target. The value becomes larger than the vehicle speed V _t .

Next, similarly to steps S4 and S5, the inter-vehicle distance D and the vehicle speed V are read (step S15). This is because it is necessary to newly read the inter-vehicle distance D and the vehicle speed V here because the routine described below is repeated after the overtaking operation is completed.

The target inter-vehicle distance D _T is calculated based on the vehicle speed V read in step S15 as in step S7 (step S16). However, the constant here is different from the calculation formula here, and the constants α and β here are
From the target inter-vehicle distance D _{t in} step S7, step S16
The target inter-vehicle distance D _T at is selected to be larger.

After that, it is judged from the output signal of the winker switch 4a whether or not the winker is operated to the left (step S17), and when the winker is not operated to the left, that is, the lane is changed. When I found out that I was driving in the passing lane,
Since the target vehicle speed continues to be controlled with the corrected high value V _T , the overshooting control routine is exited if the target vehicle speed continues for a certain time T ₀ or more in step S18, but it is not so. Sometimes, the process proceeds to step S19, and it is determined whether the target inter-vehicle distance D _T is larger than the actual inter-vehicle distance D as in step S8.

As a result, when it is found that D _T > D, the inter-vehicle distance is short and it is in a dangerous state, so the deceleration is calculated in step S20. This deceleration calculation formula uses the same constants as in step S9 and α =
It can be obtained by K1 × (D _T −D) + L1.

When it is found that D _T > D is not satisfied, the vehicle is accelerated because the safe inter-vehicle distance is maintained. Therefore, the acceleration α is obtained by the arithmetic expression shown in step S21. This calculation formula is the same as in step S10, and α
= A _{K2 × (V T -V) +} L2. In this case, α
The constants K2 and L2 are selected so as to take positive values.

Based on the acceleration / deceleration α thus obtained,
As described above, the throttle operation amount Δθ or the brake operation amount ΔP is calculated according to FIG. 5 (step S22), and in the case of the throttle operation amount Δθ, the throttle valve actuator 5 is controlled by the motor drive circuit 12, and the brake operation amount ΔP In this case, speed control is performed by controlling the pressure control valve 6 via the D / A converter 13 (step S2).
3).

After this, in steps S24 and S25, the set switch 3 is turned off as in steps S1 and S2.
This control routine is terminated when the set switch 3 is OFF, or when the set switch 3 is ON but the release operation is performed. When 3 is ON and the releasing operation is not performed, the process returns to step S15 to execute the control routine for overtaking similar to the above.

When it is determined in step S17 that the winker is operated to the left, step S2
At 6, it is determined whether or not the steering angle θ detected by the steering angle sensor 4b exceeds a constant steering angle θ ₀ corresponding to a lane change. If not, the process proceeds to step S18, but exceeds θ _0. When the vehicle is in the overtaking state, the lane change is performed, and it means that the vehicle has returned to the original traveling lane again, and this control routine is ended.

[0040]

As described above, according to the vehicle speed control device of the present invention, when it is confirmed that the driver intends to overtake by changing the lane at the time of constant speed driving, If the distance from the preceding vehicle is safe from the relationship between the target inter-vehicle distance obtained from the vehicle speed and the current inter-vehicle distance, the target vehicle speed will be accelerated to a value that is temporarily corrected to make a nice overtaking and the lane change destination When the vehicle is traveling in the overtaking lane, it is configured to follow the preceding vehicle keeping a certain inter-vehicle distance,
When overtaking, you do not need to operate the accelerator by yourself, and you can improve the easy driveability while maintaining a safe distance between vehicles.

[Brief description of drawings]

FIG. 1 is a block diagram showing the principle of a vehicle speed control device according to the present invention.

FIG. 2 is a block diagram showing an embodiment of a vehicle speed control device according to the present invention.

FIG. 3 is a flowchart of a control program (No. 1) executed by a controller used in the vehicle speed control device according to the present invention.

FIG. 4 is a flowchart of a control program (No. 2) executed by a controller used in the vehicle speed control device according to the present invention.

FIG. 5 is a memory map diagram showing the relationship between acceleration / deceleration and throttle or brake operation amount used in the present invention.

[Explanation of symbols]

1 inter-vehicle distance detecting means (radar device) 2 vehicle speed detecting means (speed sensor) 3 target vehicle speed setting means (auto cruise set switch) 4 lane change confirming means 5 engine output adjusting means 6 braking force adjusting means 10 control means (controller) In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirotoshi Akiyama 8 Tsutana, Fujisawa City Kanagawa Prefecture Isuzu Central Research Institute Co., Ltd. (72) Inventor Zuagi Nadomi 8th Tsutana, Fujisawa City Kanagawa Prefecture Isuzu Central Research Co., Ltd. In-house (72) Inventor Shinjiro Endo 8 Tsutana, Fujisawa, Kanagawa Prefecture Isuzu Central Research Institute

Claims (1)

[Claims] 1. A means for detecting an inter-vehicle distance between a front vehicle and an own vehicle, a vehicle speed detecting means, a target vehicle speed setting means, an engine output adjusting means, a braking force adjusting means, and a lane change confirming means. , When the target vehicle speed is set by the target vehicle speed setting means, when the lane change at the time of overtaking is confirmed, the target vehicle speed is corrected, and the target vehicle distance is calculated based on the current vehicle speed. When the danger is greater than the inter-vehicle distance, the target deceleration is obtained based on the target inter-vehicle distance and the current inter-vehicle distance, and the braking force adjusting means is controlled.
And a means for controlling the engine output adjusting means by obtaining a target acceleration based on the corrected target vehicle speed and the current vehicle speed when the target inter-vehicle distance is smaller than the current inter-vehicle distance. The vehicle speed control device.