JPS628836A - Controlling device for distance between two cars - Google Patents

Abstract

PURPOSE:To enable a driver to change a distance between two cars arbitarily by providing a means which can set an optimum distance between two cars depending on the road condition, for a controlling device for the distance between two cars, which is employed by an automatic drive device which allows a car to run at a constant speed on an expressway. CONSTITUTION:This device includes a car speed detecting means A, a distance between two cars detecting means B, a car speed vs. distance between two cars curve memory means E, a parameter decision means D, and a car speed change means C. And the plural number of curves for car speed vs. distance between two cars which are selected by a parameter, is stored in the curve memory means E. And the value of the parameter is determined by the parameter decision means D. The car speed change means C changes the car speed in such a way that the car speed matches the equivalent distance between two cars specified by the car speed vs. distance between two cars curve selected by the parameter which has been already decided. Accordingly, as the value of the parameter can be determined arbitarily depending on the road condition, the car speed is controlled so as to maintain a new target distance between two cars which is selected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inter-vehicle distance control device that maintains an appropriate inter-vehicle distance to a preceding vehicle.

[Prior Art] Autodrive devices, which are convenient for driving at a constant speed for long periods on expressways, cannot be used when there is a vehicle in front. Therefore, in recent years, it has been proposed to attach an inter-vehicle distance control device to the above-mentioned auto-drive device and switch to inter-vehicle distance control when a preceding vehicle appears (Japanese Patent Laid-Open No.
No. 8-203524).

[Problems to be Solved by the Invention] However, since conventional inter-vehicle distance control devices maintain a single target inter-vehicle distance predetermined at the time of device design, the optimal inter-vehicle distance according to the road conditions cannot be set arbitrarily. There was a problem that it could not be set to .

SUMMARY OF THE INVENTION In view of these problems, it is an object of the present invention to provide an inter-vehicle distance control device that allows a driver to arbitrarily change a target inter-vehicle distance depending on road conditions.

[Means for Solving the Problems] As shown in FIG. 1, the device of the present invention includes vehicle speed detection means, inter-vehicle distance detection means, vehicle speed-intervehicle distance curve storage means, parameter determination means, and vehicle speed changing means. ing.

The storage means stores a plurality of vehicle speed-to-vehicle distance curves selected by parameters, and the values of the parameters are determined by the parameter determination means. Therefore, the vehicle speed changing means is configured to adjust the vehicle speed to -
Change the vehicle speed so that the vehicle speed and inter-vehicle distance match the inter-vehicle distance curve.

[Effects] According to the present invention, parameter values can be arbitrarily determined according to road conditions by the parameter determining means, and the vehicle speed is thereby controlled so as to maintain the newly selected target inter-vehicle distance. Ru.

[Example] In FIG. 2, 1 is a known inter-vehicle distance detection device,
Measures the presence or absence of a vehicle in front and the distance between vehicles using radio waves, sound waves, etc. Reference numeral 2 denotes a vehicle speed detection device, which includes a vehicle speed sensor and outputs vehicle speed data. 3 is a switch for instructing determination of parameters to be described later, and 4 is a microcomputer having an input/output interface. Reference numeral 5 denotes a vehicle speed control device which operates a throttle valve in response to a vehicle speed control signal from the computer 4 to change and control the vehicle speed. Reference numeral 6 denotes a display device that displays the distance between vehicles and the like.

FIG. 3 shows an outline of the processing program of the computer 4. The program is periodically executed by a timer interrupt built into the computer, and in steps 101 and 102, vehicle speed data VS and inter-vehicle distance data d are respectively input. Next, a parameter selection routine (described later) and a control target vehicle speed calculation routine (described later) are executed, and based on the processing results of these routines, a vehicle speed control signal is output, as well as data for displaying the inter-vehicle distance (step 103). .104).

By the way, the computer memory already contains the seventh
As shown in the figure, a group of vehicle speed-to-vehicle distance curves selected by n parameters pk is stored. These curve groups are expressed by the following equation, where f is a function.

do=f (vs, pk) Here, do is the target inter-vehicle distance at the vehicle speed VS. Further, Vmax and Vmin in the figure are the upper and lower limits of the controllable vehicle speed VS.

FIG. 4 shows a parameter determination routine. This routine is executed when the command switch 3 is turned on (step 201), and when there is a preceding vehicle and the vehicle speed vsi at the time of the switch is turned on is within a controllable range (step 202).
~204), and in step 205, the parameter P is determined by the following formula:
Calculate i.

pi=g(Vsi, di) Here, di is the inter-vehicle distance when the switch is turned on, and the function q
is the solution of the above function f for the parameter pk.

In step 206, the parameter pk closest to the calculated parameter pi is selected and determined.

In the control target vehicle speed calculation routine, the determined parameter p
The target vehicle speed is calculated so as to maintain the vehicle speed-intervehicle distance curve selected by k. This is shown in FIG.

In step 301, the presence of a preceding vehicle is confirmed, and then the vehicle speed change amount Δ is calculated using the following equation (step 302).

Δv=h (d 1 - do) = h (d i -f (vs, pk)) where,
The function is the number between the broken lines shown in FIG. In the figure Xi,
It is necessary to select x2, hl, and h2 appropriately according to the response characteristics of the vehicle.
m>, x2 = -20 (m>, hl =3 (m/S
), h2 = -2 (m/S).

In step 303, the vehicle speed Vset and the vehicle speed (Vl+ΔV)
Set the smaller one as the target vehicle speed VO. Here, V
set is the constant target vehicle speed when there is no preceding vehicle, and V
l is the estimated vehicle speed of the preceding vehicle. The estimated vehicle speed (1) is obtained by adding the vehicle speed VS to the relative speed determined from the amount of change in the inter-vehicle distance d. Note that when there is no preceding vehicle, the constant target vehicle speed vset is set to the target vehicle speed Vo (
Step 304).

By repeating steps 302 and 303, for example, if the inter-vehicle distance di is larger than the target inter-vehicle distance do, the target vehicle speed Vo is set larger than the vehicle speed v1 of the preceding vehicle, and the preceding vehicle gradually approaches the preceding vehicle. The vehicle speed becomes almost the same as that of the vehicle speed, and the target inter-vehicle pressure ldo at this vehicle speed selected by the parameter Pk is maintained.

In the device configured as described above, when changing the target inter-vehicle distance according to road conditions, first stop the control by this device, change the inter-vehicle distance to the preceding vehicle to the desired distance by normal manual operation, and then Then, the command switch 3 is turned on and the parameter determination routine shown in FIG. 4 is executed.

Incidentally, the parameters in the above embodiments may be directly determined by providing a multi-value switch.

Further, a display device for indicating the inter-vehicle distance is not particularly required.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of the present invention, Fig. 2 is a block diagram showing the hardware configuration of the device, Figs. The graph shown in FIG. 7 is a bluff showing a vehicle speed vs. inter-vehicle distance curve. 1... Inter-vehicle distance detection device 2... Vehicle speed detection device 3... Parameter determination command switch (parameter determination means) 4... Microcomputer 5... ...Vehicle speed change device Fig. 1 Fig. 2 Fig. 3, 47 Fig. 5 Fig. 6

Claims (2)

[Claims] (1) means for detecting the vehicle speed; means for detecting the inter-vehicle distance to the preceding vehicle; means for storing a plurality of vehicle speed-intervehicle distance curves selected by parameters; and means for determining the values of the parameters; and means for changing the vehicle speed so that the vehicle speed and the following distance match a vehicle speed-to-vehicle distance curve selected based on the determined parameters. (2) The parameter determining means has a switch for instructing parameter determination, and is set to determine the value of the parameter based on the vehicle speed and inter-vehicle distance at the time the switch is turned on. The inter-vehicle distance control device described in .