JPH03220028A - Follow running controller for vehicle - Google Patents

Abstract

PURPOSE:To quicken responsiveness in follow running control by deciding the target car speed suitable for the current intercar distance between a front vehicle and a self vehicle, and controlling the acceleration and deceleration of the self vehicle based on the difference between this target car speed and the current car speed of the self vehicle. CONSTITUTION:In case of controlling the self vehicle so that it may run following the front vehicle, a sensor A detects the intercar distance between the self vehicle and the front vehicle. Moreover, a sensor B detects the car speed of the self vehicle. Furthermore, the target car speed suitable for the current intercar distance is determined according to the predetermined relation between the detected intercar distance and the car speed, and also the quantity of the control of an accelerating/decelerating device, which accelerates/decelerates the self vehicle based on the difference between the this target car speed and the current car speed, is decided by a means C. And according to the decided quantity of control, the accelerating/decelerating device is controlled by a means D. Hereby, the responsiveness in follow running control can be quickened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a tracking control device for a vehicle that causes the own vehicle to follow a vehicle in front, and is particularly famous for improving its response speed. .

An example of a conventional technical follow-up travel control device is described in Japanese Patent Application Laid-open No. 121130/1983. This is based on the current vehicle speed detected by (a) the vehicle speed sensor that detects the vehicle speed of the own vehicle, (b) the inter-vehicle distance sensor that detects the distance between the own vehicle and the vehicle in front of it, and (C) the vehicle speed sensor. Control amount determination that determines an appropriate target inter-vehicle distance and determines the control amount of the acceleration/deceleration device that accelerates and decelerates the own vehicle based on the difference between the target inter-vehicle distance and the current inter-vehicle distance detected by the inter-vehicle distance sensor. means and
(d) Acceleration/deceleration device control means for controlling the acceleration/deceleration device using the control amount.

Problems to be Solved by the Invention This tracking travel control device determines the control amount of the acceleration/deceleration device (hereinafter referred to as acceleration/deceleration amount) based on the amount of deviation in the following distance,
The acceleration/deceleration device was controlled using the control amount. However, when the amount of acceleration/deceleration is changed, the result first appears as a change in vehicle speed, and then a change in the following distance appears due to the change in vehicle speed, so it takes time for the result to appear after the control is performed. There was a problem that it took a while.

An object of the present invention is to realize follow-up travel control with good control responsiveness in a follow-up travel control device by determining a target vehicle speed with respect to the inter-vehicle distance and determining the amount of acceleration/deceleration based on this target vehicle speed. It was done as such.

Means for Solving the Problems The gist of the present invention is, as shown in FIG. 1, in a vehicle follow-up travel control device including the following distance sensor, vehicle speed sensor, control amount determining means, and acceleration/deceleration device control means.
The control amount determining means determines a target vehicle speed suitable for the current inter-vehicle distance detected by the inter-vehicle distance sensor according to a predetermined relationship between the inter-vehicle distance and the vehicle speed, and also determines the target vehicle speed suitable for the current inter-vehicle distance detected by the inter-vehicle distance sensor, and Based on the difference from the current vehicle speed,
The control amount of the acceleration/deceleration device is determined.

Operation and Effects of the Invention In the device of the present invention, the control amount of the acceleration/deceleration device, that is, the acceleration/deceleration amount, is determined based on the difference between the current vehicle speed and the target vehicle speed, that is, the deviation amount of the vehicle speed. Compared to the case where the determination is based on the difference between the target vehicle distance and the target vehicle distance, that is, the deviation amount of the vehicle distance, the response speed of the follow-up cruise control is faster.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

A follow-up travel control device according to an embodiment of the present invention includes a computer 10, as shown in FIG.

The computer 10 is composed of a CPU, ROM, RAM, bus, input interface, output interface, etc. The input interface includes an inter-vehicle distance sensor 12 that detects the inter-vehicle distance between the vehicle in front and the host vehicle. A vehicle speed sensor 14 that detects the vehicle speed of the own vehicle is connected. on the other hand,
The output interface includes a brake actuator 20 that controls the brakes of each of the four wheels of the host vehicle. A throttle actuator 22 that controls a throttle valve provided in the intake manifold of the engine is connected.

The ROM stores various control routines, including the follow-up travel control routine shown in the flowchart of FIG.

The ROM also stores a map defining the relationship between the inter-vehicle distance and the target vehicle speed, which is shown graphically in FIG. Hereinafter, based on FIG. 3 and FIG. 4, how the follow-up travel control is performed will be explained.

The follow-up travel control is realized by executing the routine shown in FIG. 3 at predetermined intervals. When this routine is executed each time, first, in step Sl (hereinafter simply referred to as Sl; the same applies to other steps), the current inter-vehicle distance is measured based on the detection result of the inter-vehicle distance sensor 12. Thereafter, in S2, a target vehicle speed corresponding to the current inter-vehicle distance is determined using a map stored in the ROM.

Subsequently, in S3, the determined target vehicle speed is set to RA.
After being stored in M, in S4, the own speed, which is the current speed of the own vehicle, is measured based on the detection result of the vehicle speed sensor 14.

Subsequently, in S5, it is determined whether the host vehicle speed is greater than the target vehicle speed. If it is assumed that the own vehicle speed is greater than the target vehicle speed this time, the result of the determination will be YES, and in S6, the target deceleration of the own vehicle is calculated based on the difference between the own vehicle speed and the target vehicle speed, and then in S7, The brake fluid pressure control amount or throttle opening control amount necessary to achieve the target deceleration is calculated, and in S8, the brake actuator 20 or throttle actuator 22 is controlled with each control amount. If the target deceleration can be achieved by engine braking, only slot control is executed, and if it cannot be achieved by throttle control alone, throttle control and brake control are executed together.

On the other hand, if it is assumed that the own vehicle speed is less than the target vehicle speed, the determination result in S5 is NO, and in S9 the target acceleration of the own vehicle is calculated based on the difference between the own vehicle speed and the target vehicle speed. After that, at Slo, the throttle opening control amount necessary to achieve the target acceleration is calculated.
At 311, the throttle actuator 22 is controlled by the throttle opening amount a. Furthermore, in Sll, if the brake actuator 20 is currently in the operating state, it is also returned to the non-working state. This completes one execution of this routine.

If the execution of this routine is repeated as described above,
The actual acceleration/deceleration of the own vehicle is controlled so that the relationship between the current inter-vehicle distance and the own vehicle speed is maintained as shown in FIG. The own vehicle starts, stops, accelerates, and performs W speed while following the vehicle in front.

As is clear from the above explanation, in this example,
Since the brake fluid pressure control amount and the throttle opening control amount are calculated based on the difference between the target vehicle speed and the own vehicle speed, the response speed of the follow-up cruise control is improved.

Furthermore, as the response speed of the follow-up cruise control improves, the control accuracy of the relationship between the current inter-vehicle distance and the own vehicle speed also improves.

As is clear from the above explanation, in this example,
Brake actuator 20. The throttle actuator 22 constitutes an acceleration/deceleration device, and the computer 10 operates S1 to S7 in FIG. A portion of the computer 10 that executes S9 and S10 constitutes a control amount determining means, and a portion of the computer 10 that executes 88 and S11 in the figure constitutes an acceleration/deceleration device control means.

In the above embodiment, the target vehicle speed is uniquely determined according to the current inter-vehicle distance, but the relationship between the target vehicle speed and the current inter-vehicle distance may be changed depending on the situation in which the own vehicle is placed. Good too. An example in which the relationship can be changed will be described below with reference to FIGS. 5 and 6. It should be noted that elements common to the above embodiments are denoted by the same reference numerals to indicate correspondence, and detailed explanations will be omitted.

FIG. 5 is a flowchart showing the following cruise control routine stored in the ROM of the computer 10, and FIG. 6 shows two graphs each representing two types of maps that define the relationship between the following distance and the target vehicle speed. . In this embodiment, the map that defines the relationship between the inter-vehicle distance and the target vehicle speed is used for the approach when the host vehicle and the vehicle in front are relatively close to each other;
For non-approaching situations in which the inter-vehicle distance does not change or the host vehicle and the vehicle in front are relatively far apart, separate maps are provided for approaching situations and non-approaching situations.

In order to improve the driving feeling, it is desirable that when the own vehicle accelerates, the acceleration of the own vehicle increases almost proportionally to the increase in the own vehicle speed, whereas when the own vehicle decelerates, the acceleration of the own vehicle increases in proportion to the increase in the own vehicle speed. It is desirable that the distance be approximately constant regardless of the speed of the own vehicle. In view of these circumstances, the sixth
In the figure, the graph representing the non-approach map is a straight line sloping upward to the right, and the graph representing the approaching map is an upwardly convex curve sloping upward to the right.

Further, the graph for approaching is set above the graph for non-approaching. Therefore, it is possible for the host vehicle to both start and stop smoothly.

Further, each of the target vehicle speeds to be determined using these two graphs has an upper limit, and the upper limit is the vehicle speed set by the driver. Therefore, if the current inter-vehicle distance becomes longer than the inter-vehicle distance corresponding to the set vehicle speed,
In reality, constant speed driving will be performed instead of follow-up driving.

Next, the operation will be explained.

The routine shown in FIG. 5 is also executed at predetermined time intervals.

When this routine is executed each time, first in step 5101, the own vehicle speed is measured based on the detection result of the vehicle speed sensor 14, and the own vehicle speed is stored in the RAM of the computer 10.
Then, in 5102, the current inter-vehicle distance is measured based on the detection result of the inter-vehicle distance sensor 12, and the current inter-vehicle distance is stored in the RAM. After that, in 5103, the current inter-vehicle distance is changed to the front inter-vehicle distance,
That is, the inter-vehicle distance difference is calculated by subtracting the value stored in the RAM as the current inter-vehicle distance during the previous execution of this routine, and it is determined in 5104 whether the sign of the inter-vehicle distance difference is negative. Based on this, it is determined whether or not it is the time of approach.

If the current inter-vehicle distance is shorter than the preceding inter-vehicle distance, the result of the determination is YES because it corresponds to the case of approaching, and in 5105, the approach map is selected from the two maps, whereas the current inter-vehicle distance is selected. If the distance is equal to or longer than the distance in front of the vehicle, 51.
The determination result in step 04 is No, and in step 5106, the non-approach map is selected.

In either case, the target vehicle speed corresponding to the current inter-vehicle distance is then determined at 5107 using the map selected at 5105 or 5106. This time as well as last time, if you are in a non-approach state, the map for non-approach,
If the vehicle is approaching, the target vehicle speed is determined according to the approach map. On the other hand, if you were in a non-approach state last time but are in an approach state this time, or if you were in an approach state last time but are in a non-approach state this time, in other words, this time is a transition from a non-approach state to an approach state. When the vehicle is moving from the approach state to the non-approach state, the target vehicle speed is determined using a method different from that used in the above case.

If this is the time of transition from the non-approaching state to the approaching state, the target vehicle speed is set to the value stored as the target vehicle speed during the previous execution of this routine.

Also, from the time of transition, the current inter-vehicle distance and the target vehicle speed are
The current target vehicle speed is set to be the previous target vehicle speed until the following distance decreases to the corresponding distance in the approach graph shown in the figure.

For example, when point P, where the current inter-vehicle distance and target vehicle speed correspond to each other, moves diagonally upward to the right along the graph for non-approaching shown in the figure and reaches point A, when the own vehicle When the vehicle moves from the approaching state to the approaching state, the target vehicle speed is fixed from the time it reaches point A until the current inter-vehicle distance decreases to the inter-vehicle distance at point B on the approach graph. .

On the other hand, if this is the time of transition from the approaching state to the non-approaching state, the target vehicle speed is set to the value stored as the target vehicle speed during the previous execution of this routine. Also, from the time of transition until the target vehicle speed increases to the corresponding distance in the non-approaching graph shown in the same figure, the current target vehicle speed will be treated as the previous target vehicle speed. It has also become For example, when point Q, where the current inter-vehicle distance and target vehicle speed correspond to each other, moves diagonally downward to the left along the approaching graph shown in the same figure and reaches point C, the own vehicle moves away from the approaching state. When the non-approaching state is entered, the target vehicle speed is fixed from the time point C is reached until the current inter-vehicle distance increases to the inter-vehicle distance at the point on the graph for non-approaching states.

Therefore, in this embodiment, a state in which the corresponding point does not exist on either the non-approaching graph or the approaching graph, i.e., a state in which the corresponding point exists within an area surrounded by these two graphs. Even if changes between the non-approaching state and the approaching state are repeated relatively frequently, the target vehicle speed is fixed, which prevents the own vehicle from accelerating and decelerating frequently, and improves driving performance. The effect of improving the ring can be obtained.

Thereafter, at 510B in FIG. 5, the target acceleration/deceleration of the own vehicle is calculated based on the difference between the target vehicle speed and the own vehicle speed, and the actual acceleration/deceleration of the own vehicle is measured based on the detection result of the vehicle speed sensor 14. Ru.

Next, in 5109, the brake fluid pressure control amount and the throttle opening control amount are calculated based on the difference between the target acceleration/deceleration and the actual acceleration/deceleration, and then in 5110,
The brake actuator 20 is controlled by the brake fluid pressure control amount, and at 5ill, the throttle actuator 22 is controlled by the throttle opening control amount.

As is clear from the above explanation, in this example,
Brake actuator 20. The throttle actuator 22 constitutes an acceleration/deceleration device, the part of the computer 10 that executes steps 5101 to 5109 in FIG. It constitutes an acceleration/deceleration device control means.

When moving your vehicle from an acceleration state to a deceleration state,
Due to delays in throttle valve operation, inertia of the rotating parts of the own vehicle, inertia of the own vehicle itself, etc., the desired deceleration state may not always be achieved immediately, and the own vehicle may suddenly suddenly collide with the vehicle in front. expected to be close to. Therefore,
It is desirable to set the inter-vehicle distance to the vehicle ahead during acceleration to be longer than the inter-vehicle distance during deceleration. When accelerating, it is desirable to set a long inter-vehicle distance to the vehicle ahead to prevent the own vehicle from getting too close to the vehicle ahead due to future deceleration. In this embodiment, as is clear from FIG. 6, the current inter-vehicle distance corresponding to the same target vehicle speed is longer when the vehicle is not approaching than when it is approaching, so there is a transition from acceleration to deceleration. This also has the effect of preventing the host vehicle from suddenly approaching the vehicle in front when the vehicle is moving.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a block diagram conceptually showing the configuration of the present invention. FIG. 2 is a block diagram showing the configuration of a vehicle follow-up travel control device that is an embodiment of the present invention. FIG. 3 is a flowchart showing a follow-up travel control routine stored in the ROM of the computer in FIG. FIG. 4 is a graph showing the relationship between the inter-vehicle distance and target vehicle speed stored in the ROM. FIG. 5 is a flowchart showing a follow-up travel control routine in another embodiment. FIG. 6 is a graph showing the relationship between inter-vehicle distance and target vehicle speed used in another embodiment. 10: Computer 12: Inter-vehicle distance sensor 14: Vehicle speed sensor 20 Brake actuator 22: Throttle actuator Fig. 2 Fig. 1 Fig. 4 Fig. 3 Fig. 5

Claims (1)

[Claims] A vehicle tracking control device that causes a vehicle to follow a vehicle in front, comprising: an inter-vehicle distance sensor that detects the distance between the host vehicle and the vehicle in front; and a vehicle speed sensor that detects the vehicle speed of the host vehicle. A target vehicle speed suitable for the current inter-vehicle distance detected by the inter-vehicle distance sensor is determined according to a predetermined relationship between the inter-vehicle distance and the vehicle speed, and the target vehicle speed and the vehicle speed sensor are control amount determining means for determining a control amount of an acceleration/deceleration device for accelerating or decelerating the host vehicle based on the difference from the detected current vehicle speed; and acceleration/deceleration device control means for controlling the acceleration/deceleration device using the control amount. A vehicle follow-up travel control device comprising: