JPH06251299A - Vehicle speed control device - Google Patents

Abstract

(57) [Summary] [Purpose] In a vehicle speed control device having a function of follow-up running control for maintaining a vehicle-to-vehicle distance from a vehicle ahead, it is possible to select whether or not to follow-run according to the running situation. A follow-up traveling setting means is provided, and only when the follow-up traveling is set, the controller shifts the shift reference from a normal shift map when the follow-up traveling is not set to a low speed side prepared in advance for the follow-up traveling. Switch to the shift map and execute follow-up running.

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 having an inter-vehicle distance control (following traveling control) function.

[0002]

2. Description of the Related Art In order to improve easy driveability,
Recently, the number of vehicles equipped with a speed control device that performs a constant speed traveling (auto-cruise) function to control the vehicle to travel at a constant speed has been increasing recently. In this speed control device, the driver operates the accelerator pedal. Without doing so, the engine output is controlled by adjusting the throttle opening etc. so that the speed of the host vehicle can be kept constant.

However, with this speed control device, there is a risk of a rear-end collision when the vehicle ahead is slower than the host vehicle. Therefore, recently, a device has been developed which detects the inter-vehicle distance to a vehicle ahead and maintains a predetermined safe inter-vehicle distance.

In the prior art disclosed in Japanese Patent Laid-Open No. 55-86000, which is an example thereof, the safe inter-vehicle distance is calculated according to the vehicle speed, and the throttle opening is performed when there is no vehicle in front within the safe inter-vehicle distance. The constant speed traveling control is performed with the vehicle speed set as a target by adjusting the degree, and if it exists, the following traveling control is performed by reducing the throttle opening so that the safe inter-vehicle distance is achieved.

[0005]

By the way, in the above-mentioned prior art and the like, when the vehicle of the automatic transmission is controlled to travel at a constant inter-vehicle distance from the vehicle in front, the conventional shift timing is, for example, highway. The shift operation is frequently performed even when the vehicle is traveling, and the shift shock causes discomfort to the driver.

This will be described with reference to FIG. 5 (a).
If you go uphill or accelerate the vehicle ahead while driving at 00km / h, the throttle will be opened wide, so the gear will be 5th gear →
It shifts down to 4th gear, but when it reaches a steady state, it returns to the throttle and shifts up from 4th gear to 5th gear. Therefore, the shift operation between the fourth speed and the fifth speed is increased, which gives the driver an unpleasant feeling.

Therefore, according to the present invention, in order to improve the above-mentioned problems, constant speed traveling control is performed when no preceding vehicle is present within the safe inter-vehicle distance, and when the vehicle is present, follow-up traveling is performed so that the safe inter-vehicle distance is reached. An object of the present invention is to enable a speed control device for a vehicle to be controlled to select whether or not to follow the vehicle depending on a driving situation.

[0008]

In order to achieve the above-mentioned object, a vehicle speed control device according to the present invention is a vehicle speed control device for setting a target vehicle speed of a vehicle equipped with an automatic transmission and an actual vehicle distance between a vehicle in front of the vehicle. A means for detecting the distance, an actual vehicle speed detecting means, a vehicle speed control means, an operation start detecting means, an operation release detecting means, the operation start detecting means detects the operation start, and the operation release detecting means releases the operation. While not detecting, the target inter-vehicle distance is obtained from the actual vehicle speed, and when the target inter-vehicle distance is greater than the actual inter-vehicle distance, the vehicle speed change amount is obtained based on the difference between the two inter-vehicle distances and the target inter-vehicle distance is calculated as the actual inter-vehicle distance. When it is smaller than the target vehicle speed, the controller includes a controller that controls the vehicle speed control means by obtaining a vehicle speed change amount based on the difference between the target vehicle speed and the actual vehicle speed. When Look, the controller, and configured to switch the shift map for following distance that the lower speed which is previously prepared from a normal shift map to move the shift reference when not the follow-up run.

Further, in the present invention, the target vehicle speed may be preset in the controller without using the setting means.

[0010]

In the vehicle speed control device according to the present invention,
The controller executes the following operation, for example, when the driver sets the follow-up running by the follow-up running setting means.

First, until the operation start is detected by the operation start detecting means and the release is detected by the operation release detecting means, the target vehicle-to-vehicle distance is obtained from the actual vehicle speed by the actual vehicle speed detecting means, and the target inter-vehicle distance is obtained. The distance is compared with the actual inter-vehicle distance detected by the means for detecting the actual inter-vehicle distance to the preceding vehicle.

As a result of this comparison, when the target inter-vehicle distance> the actual inter-vehicle distance, the vehicle speed change amount is obtained based on the difference between the two inter-vehicle distances (target inter-vehicle distance-actual inter-vehicle distance).

On the other hand, when the target inter-vehicle distance <the actual inter-vehicle distance, the difference between the two inter-vehicle distances becomes negative and the above control cannot be applied. In this case, the target vehicle speed of the vehicle is set by the means. The vehicle speed change amount is obtained based on the difference between the target vehicle speed (or the target vehicle speed stored in the controller itself) and the actual vehicle speed (target vehicle speed> actual vehicle speed at this time).

Since the vehicle speed control means is controlled by the calculated vehicle speed change amount, the vehicle speed is decelerated so as to reach the target inter-vehicle distance when the vehicle ahead is short, and the target vehicle speed is constant when the vehicle ahead is not reaching the target inter-vehicle distance. Acceleration / deceleration is performed so that high speed traveling is performed.

The follow-up running is carried out in this manner, but the shift map of the automatic transmission at this time is not a normal shift map (see FIG. 5 (a)), but the shift reference to the low speed side prepared in advance in the controller. The shift map for follow-up travel (see (b) in the figure) that has been moved is selected. Discomfort to the driver can be eliminated.

On the other hand, the controller does not perform the follow-up running control when the follow-up running is not set, so that the running by the automatic transmission according to the normal shift map is performed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an embodiment of a vehicle speed control device according to the present invention. Each block will be described in sequence.

1: Inter-vehicle distance detecting means, which is composed of, for example, an FM-CW radar, a laser radar, an ultrasonic sensor or the like, which detects the inter-vehicle distance to the vehicle in front.

2: Vehicle speed detecting means This is composed of a sensor for detecting the traveling speed of the host vehicle, and usually a reed switch or the like is used.

3: Actuation start detecting means Normally, it is constituted by a digital switch (push switch etc.), and this switch is turned off by the operation of the driver.
The speed control of the present invention is started when it is detected that the state has changed to the ON state.

4: Operation release detecting means This is to detect the case where the driver operates the brake pedal, the shift lever, or a predetermined switch to release the speed control of the present invention.

5: Target vehicle speed setting means It is composed of a volume (knob), a rotary switch or the like so that the driver can set an arbitrary value, and it is possible to adjust the numbers such as a mechanism for adjusting the time of the clock. Anything is fine. It may also include a display unit for notifying the driver of the set value. When the target vehicle speed is set in the controller, which will be described later, this means 5 may be omitted.

6: Controller An input port 61 for reading the input signals from the respective means 1 to 5 described above, the programs shown in FIGS. 2 and 3 and fixed control parameters, etc. are stored in advance, and the controllers shown in FIGS. R) in which the shift map for the automatic transmission shown in FIG.
An OM 62, a RAM 63 for temporarily storing input signals and variable control parameters, a CPU 64 for performing arithmetic processing based on the program, and an output port 65 for sending output signals to each operation means described later. Control means.

7: Throttle operating means Normally, it is composed of a motor, a valve, etc., and operates the throttle position of the engine (not shown) based on the output signal from the controller 6.

8: Gear position operating means For operating the gear position (including overdrive) of the automatic transmission based on the output signal from the controller 6, which is well known in conformity with the structure of the automatic transmission of an automatic vehicle. Good.

9: Brake operating means Normally, it is composed of a hydraulic valve or the like, and operates the deceleration force (brake force) based on the output signal from the controller 6.

10: Follow-up running setting means A follow-up running set switch, which is set by the driver when the driver wants to follow the preceding vehicle on a highway, for example.

The throttle operating means 7, the gear position operating means 8 and the brake operating means 9 constitute a vehicle speed control means.

The operation of the above embodiment will be described below with reference to the flow charts of the control programs shown in FIGS. These control programs are executed by the controller 6
It is stored in the internal ROM 62 and is executed by the CPU 64 at a predetermined constant cycle. Also, the CPU 64
It is assumed that a setting flag described later is turned off when is initialized by turning on an ignition key (not shown).

Control program step 21 in FIG . 2 : Judge the state of the setting flag indicating whether or not speed control is being executed, and if ON, proceed to step 24, OF
If F (when the ignition key is ON), step 22
Go to.

Step 22: If the operation start detecting means (set switch) 3 is turned on by the driver's operation, the process proceeds to step 23, and if it is off (not operated), the process proceeds to step 26.

Step 23: Set the setting flag to ON and proceed to step 24.

Step 24: The operation release detecting means 4 detects whether or not the driver is performing a predetermined speed control release operation (stepping on the brake pedal, changing the shift lever position, etc.), and is performing the release operation (YES). If so, the process proceeds to step 25, and if not operated (NO), the process proceeds to the speed control subroutine of step 30 (see FIG. 3).

Step 25: Turn off the setting flag and proceed to step 26.

Step 26: Release the speed control shown in FIG.
The throttle opening, braking force, and gear position are determined according to the driving operation of the driver. Incidentally, as the shift map of the automatic transmission at this time, a normal shift map as shown in FIG. 5 (a) is used.

Subroutine in FIG . 3 (Details of Step 30 in FIG. 2) Step 31: First, it is judged whether or not the follow-up running setting means 10 is turned on (step 31). If not, this subroutine is executed. However, if it is found that it is thrown in, the process proceeds to the next step 32.

Step 32: Since it is found from step 31 that the driver wants to follow the traveling,
The normal shift map shown in (a) is switched to the shift map at the time of following travel control shown in (b) of the same figure. this is,
This is performed by the CPU 64 of the controller 6 switching the shift map read from the ROM 62.

Step 33: The target vehicle speed Vt is read by the target vehicle speed setting means 5. At this time, the target vehicle speed Vt is set not by the target vehicle speed setting means 5 but by the R of the controller 6.
A value preset in the OM 62 (for example, 100 km / h, which is the speed limit for general highways) may be used.

Step 34: The current inter-vehicle distance D is read by the inter-vehicle distance detecting means 1.

Step 35: The current vehicle speed V is read by the vehicle speed detecting means 2.

Step 36: An inter-vehicle distance estimated to be appropriate for traveling at the current vehicle speed V is calculated, and this value is set as a target inter-vehicle distance Dt. This target inter-vehicle distance Dt is, for example,
Obtained from a linear expression such as Dt = AV + B (A and B are constants), or 12 m if 40 km / h, 20 m if 60 km / h
, 80 km / h, the value of the target inter-vehicle distance Dt for the vehicle speed V such as 32 m is stored in the ROM 62 as a table.

Step 37: The current inter-vehicle distance D is compared with the target inter-vehicle distance Dt, and if Dt ≧ D (that is, if the preceding vehicle exists within the range of the target inter-vehicle distance Dt), the inter-vehicle distance D is targeted. In order to control the value of the inter-vehicle distance Dt, the process proceeds to step 38. On the contrary, if Dt <D (that is, if there is no preceding vehicle within the range of the target inter-vehicle distance Dt), the process proceeds to step 39 to control the vehicle speed V to the value of the target vehicle speed Vt.

Step 38: How much the vehicle speed V should be accelerated or decelerated, that is, the current vehicle speed V
Change (acceleration / deceleration) ΔV is calculated. The value of this variation ΔV can be obtained based on the value of (Dt−D) which is the difference between the target inter-vehicle distance Dt and the current inter-vehicle distance D. For example, it can be obtained by a linear expression such as ΔV = X * (Dt−D) + Y (X and Y are constants).

In this case, the vehicle ahead is approaching and is dangerous, so it is necessary to decelerate, and the constants X and Y are set so that ΔV becomes a negative value.

Step 39: Similar to step 38, the change amount ΔV of the vehicle speed V at the present time is obtained. Since it has been found in step 37 that the preceding vehicle is not approaching and is at a safe inter-vehicle distance, it is necessary to perform constant speed traveling at the target vehicle speed Vt.

For this reason, since the equation of step 38 cannot be used as it is, the value of the variation ΔV is obtained based on the value of (Vt-V) which is the difference between the target vehicle speed Vt and the current vehicle speed V. To do. For example, ΔV = α * (Vt−V) + β
(Α and β are constants).

In this case, it is uncertain whether Vt-V or not, and when Vt> V, the target vehicle speed has not been reached, so it is necessary to accelerate. Therefore, ΔV must be an acceleration such that ΔV> 0, and both constants α and β are positive values.

On the contrary, when Vt <V, the target vehicle speed is exceeded, so it is necessary to decelerate, and ΔV must be a deceleration such that ΔV <0. Therefore, both constants α and β are also positive values.

Although only a simple example is shown in step 38 and step 39 for calculating the variation ΔV, the current vehicle speed V is known as known in the prior art.
It goes without saying that the value of ΔV may be appropriately changed in accordance with the current inter-vehicle distance D, the time variation of the inter-vehicle distance D (that is, the vehicle speed relative to the preceding vehicle), or the like.

Step 40: The throttle operation amount, the brake operation amount, and the optimum gear position are obtained based on the value of the variation ΔV obtained in step 38 or step 39.

FIG. 4 shows an example of the relationship between the variation ΔV and the throttle variation Δθ, and the variation ΔV and the braking force variation ΔP. Here, a constant Vc that takes a negative value is defined, and if ΔV ≧ Vc means acceleration or small deceleration, the throttle opening operation (Δθ) is used without braking.

On the contrary, when ΔV <Vc, a large deceleration is shown, so the throttle is fully closed and the braking force is operated (ΔP).

In FIG. 4, ΔV and Δθ, and ΔV and ΔP are shown as straight lines in a simplified manner, but of course they may be curves obtained from vehicle specifications and running resistance.

When the above speed control is executed, it is necessary to automatically perform a gear change, and the shift logic (shift timing) is as shown in FIG. 5 (a) or (b).
According to the shift map shown in (1), upshift / downshift is performed according to the current vehicle speed and throttle opening value.

[0055]

As described above, the vehicle speed control device according to the present invention is provided with the follow-up running setting means, and the controller normally operates when the follow-up running is not performed only when the follow-up running is set. Since the shift map is changed from the shift map to the shift map for the follow-up running in which the shift reference is moved to the lower speed side prepared in advance, the follow-up running is executed, the shift operation is performed in a situation where the follow-up running control such as a highway is used. Is difficult to do.

Therefore, it is possible to eliminate the unpleasant feeling given to the driver due to the reduction in the number of shifts.

[Brief description of drawings]

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

FIG. 2 is a flowchart of a control program executed by a controller used in the vehicle speed control device according to the present invention.

FIG. 3 is a flowchart of a control program for executing a “execution of speed control” subroutine in FIG.

FIG. 4 is a graph diagram for explaining an operation of a throttle opening degree and an operation of a braking force corresponding to a vehicle speed change amount in the present invention.

FIG. 5 is a diagram showing a normal shift map used in the vehicle speed control device according to the present invention and a shift map at the time of following travel control.

[Explanation of symbols]

 1 inter-vehicle distance detecting means 2 vehicle speed detecting means 3 operation start detecting means 4 operation release detecting means 5 target vehicle speed setting means 6 controller 7 throttle operating means 8 gear position operating means 9 brake operating means 10 following travel setting means Indicates the same or corresponding part.

Claims (2)

[Claims] 1. A means for setting a target vehicle speed of a vehicle equipped with an automatic transmission, a means for detecting an actual inter-vehicle distance from a vehicle in front, an actual vehicle speed detecting means, a vehicle speed control means, and an operation start detecting means. While the operation release detecting means and the operation start detecting means detect the operation start and the operation release detecting means does not detect the operation release, the target inter-vehicle distance is calculated from the actual vehicle speed, and the target inter-vehicle distance is the actual inter-vehicle distance. When the distance is greater than the distance, the vehicle speed change amount is obtained based on the difference between the two vehicle distances, and when the target vehicle distance is smaller than the actual vehicle distance, the vehicle speed change amount is obtained based on the difference between the target vehicle speed and the actual vehicle speed. In a vehicle speed control device including a controller for controlling a vehicle speed control means, a follow-up running setting means is provided, and the controller shifts to a normal shift when the follow-up running is not performed only when the follow-up running is set. Speed control apparatus for a vehicle and switches the shift map for following distance moving the shift reference to the low speed side prepared in advance from the map. 2. The vehicle speed control device according to claim 1, wherein the target vehicle speed is preset in the controller without using the setting means.