JPH03117306A - Automatic control of vehicle - Google Patents

Abstract

PURPOSE:To reduce the changing time of notch by periodically judging whether a vehicle reached to starting condition of brake control operation and performing stop control through fuzzy inference when the vehicle reaches to the brake control starting condition. CONSTITUTION:Brake control takes place when the start marging time of brake control, obtained based on the distance L1 from current position to a target point O, current speed VT1 and an expected acceleration betap, after passage of a vehicle through point P separated by a distance (l) to this side from the target point O becomes shorter than a predetermined value. In other words, distances Lz, LP, LN between an expected stop point and the target point, for current notch, single notch increment and single notch decrement, are obtained based on L1, VT1, current acceleration alphaT1 and variation of acceleration DELTAalpha for single notch change. Then a fuzzy amount mu1 for allowing stoppage within allowable error and a fuzzy amount mu2 for allowing accurate stoppage at the target stop position, corresponding to thus obtained distances, are determined through a membership function. Then a notch for providing the maximum value is selected between mu1 and mu2.

Description

[Detailed Description of the Invention] [Subject of the Invention] The present invention relates to a method for automatically controlling a vehicle, and in particular to a method for automatically controlling a vehicle, and in particular, for controlling a vehicle operated by a discrete control method such as a notch to a stop target point without frequently changing control commands. The present invention relates to an automatic control method for a vehicle that makes it possible to stop the vehicle.

[Prior art]

FIG. 1 is a block diagram showing an example of a conventional automatic train control device that automatically stops a train at a target position, and FIG. 2 is an operation explanatory diagram showing its speed pattern. In Fig. 1, 1 is a speed generator, 2 is a speed calculation circuit, 3 is a distance integration circuit, 4 is a ground transducer, 5 is a point detector, 6 is a pattern generator, 7 is a comparator, and 8 is a brake control device. And 9 indicates a brake device.

In the above-mentioned conventional fixed position stop control, the vehicle detects a point on the vehicle by detecting the beacon 4 installed at the ground rotation point P (point P) a predetermined amount wIQ before the target stop point ○ (point 0). It is detected by the device 5. The distance integration circuit 3 counts the pulses from the speed generator 1 based on the point detection signal from the point detector 5, and outputs the distance S that the vehicle has traveled from the point P. Further, the pattern generator 6 selects the distance Q to the stop target point from its own memory based on the point detection signal from the point detector 5, and selects a predetermined deceleration β.
Using 2, vp = 7.2βP Ω-8 (1
) is output as the target speed pattern V.

The speed calculation circuit 2 calculates the actual speed Va of the vehicle from the pulses of the speed generator 1. A comparator 7 compares the actual speed Va with the target speed pattern V output from the pattern generator 6. The brake device 9 is proportionally controlled via the brake control device 8 based on the output signal (Varvp) of the comparator 7, so that the actual speed VT of the vehicle follows the target speed pattern V, and the vehicle reaches the stop target. It is controlled so that it stops near point 0.

However, in the above method, the brake device 9
Due to fluctuations in the braking force and fluctuations in external force due to the slope of the trajectory, a steady deviation in tracking with respect to the target speed pattern Vp may occur, and the stopping accuracy may deteriorate. In addition, in order to prevent the occurrence of this following steady-state deviation, if integral control is performed in addition to proportional control of the brake device 9, the control command (notch)
Another problem arises as the number of changes increases and the ride quality of the vehicle deteriorates.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to reduce the number of changes in control commands (notches) as much as possible when stopping a vehicle at a target location, thereby realizing a comfortable driving experience. An object of the present invention is to provide an automatic vehicle control method.

[Detailed description of the invention]

In order to achieve the above object, the present invention provides an automatic vehicle control method in which a control command is determined according to the state of the vehicle, and speed control for stopping the vehicle is performed based on the control command. After passing a predetermined position in the foreground, the system predicts the stopping error that would occur if a predetermined brake command is given at that point, and determines whether the vehicle has reached a state where brake control should be started. A brake control start determination operation is periodically performed to determine the start of the brake control, and after the brake control start state is reached, a determination operation of a brake control command according to the state of the vehicle is performed periodically, and the vehicle is controlled according to the brake control command. It is characterized by speed control.

The determination of the brake control command is based on the control command and the state of the vehicle when the brake control command is maintained as it is.
For example, the control error predicted from the distance between the current point and the target stop point, the speed or acceleration of the vehicle, and the control error predicted when the control command is changed by a predetermined amount are compared by vague reasoning, Based on the result, one control command to be given to the vehicle is selected.

[Embodiments of the invention]

FIG. 3 is a block diagram of a vehicle fixed position stop control device showing one embodiment of the present invention, in which the same components as shown in FIG. 1 are designated by the same reference numerals. In addition, 2' is a speed acceleration calculation device that calculates the vehicle speed (actual speed) VT and acceleration α1 based on pulses from the speed generator 1 for the past 1 second, and 3' is the current position ff1 (xl) of the vehicle and the target stop point. A remaining distance calculation device 10 calculates the distance Ll from the current vehicle speed vT, the distance L1 to the target stop point ○, and a predetermined deceleration βp corresponding to a preselected notch. Using L2=L1-VT”/(7,2・β,)...
2) A predetermined notch stop correct error calculating device which calculates the stopping error L2 when the brake is applied by the notch selected in advance at the present time according to the following formula; ΔT = 3.6 L2/VT to the brake control start margin time when driving
・・・・・・・・・・・・・・・・・・It is calculated by the formula (3), and if T becomes less than a certain time (for example, 1 second), the time limit for stopping at a fixed position is determined by the formula (3). This is a brake control start command calculation device that outputs a signal to start brake control.

12Z, 12P, and 12N are the predicted stopping accuracy when the vehicle is operated under different control commands.1 For example, when the preselected notch is maintained at the current moment, when one notch is added, and when one notch is decreased, 13 is a notch change inhibiting device that generates a signal M for suppressing notch change for a predetermined period of time after the notch change, for example, one second; 14 is a stop accuracy ambiguous amount calculation device for calculating an ambiguous amount; a control notch calculation device that performs ambiguous inference based on the output and calculates a notch command N(t) to be output when notch change is inhibited;
Reference numeral 15 denotes a brake command calculation device which intermittents the output of the control notch calculation device 14 in accordance with the output of the brake control start command calculation device 11.

The operation of the apparatus of this embodiment will be explained below with reference to FIGS. 4 and 5.

FIG. 4 is a diagram for explaining the operation of determining the brake control start time for fixed-position stop control, and is a diagram for explaining the operation of determining the brake control start time for fixed-position stop control, where the vehicle is placed a predetermined distance IiQ before the target stop point
It shows a situation where the vehicle passes through and is located at X□. The above-mentioned predetermined notch stop correct error calculation device 10 calculates the stop error L2, and from this and the current speed Vt, the brake control start command calculation device 11 calculates the brake start margin time T, and calculates the brake start margin. When the time ΔT becomes less than a certain time (for example, 1 second), a brake control start command is output.

FIG. 5 is a diagram for explaining the operation of selecting a brake notch for stopping at a fixed position. The stop accuracy ambiguous amount calculation device 122.12P.

12N, the remaining distance calculation device 3 indicates the state quantity of the vehicle.
Distance to the stop target point calculated by ' @ L 1, and current speed 7-0 and acceleration α calculated by speed acceleration calculation device 2'
a, and a predetermined acceleration Δα per notch (for example,
0.5 Km/h/sec), the scalar amounts Lz, LP, and LH of the stopping accuracy, which is the control objective, are calculated using the following equation (4).

Here, the ambiguous quantity of stopping precision is.

It is assumed that there are two sets of ambiguous platforms: (1) the vehicle can be stopped within the tolerance (μm), and (2) the vehicle can be stopped accurately at the target stop position (μ2). The membership functions representing these fuzzy table sets are:

For example, it is defined as follows. When X is the stopping error (m) and the tolerance is 0.5m, the membership function μ, (x) of the ambiguous platform set that can be stopped within the tolerance is defined as The membership function μyo(x) of an ambiguous platform set that can stop at is defined as follows.

The stop accuracy ambiguous amount calculation device 112Z, 12P, 1
Each output of 2N indicates the predicted stopping accuracy by the above 2
It is expressed as an ambiguous quantity consisting of a pair of values of two membership functions μm(x) and μ2(X). That is, the scalar quantities Lz and LP of the stopping accuracy.

From LH, the ambiguous amounts Cz, cP, and CM of the stopping accuracy when the current notch is held and when the notch is changed by ±1 notch from the current value are determined as values expressed as follows.

Stopping accuracy ambiguous quantity calculation device 122.12P.

Based on the above outputs c, CP, and CN from 12N, the control notch arithmetic unit 14 operates based on fuzzy reasoning according to control laws (1) to (3) consisting of a conditional part and a conclusion part, for example, as shown below. , selects the control command to be output, that is, the notch.

(1) If the current notch can stop within the allowable range,
Keep the current notch.

(2) If it is possible to accurately stop at the target stop position with +1 notch, increase by one notch.

(3) If it is possible to accurately stop at the target stop position with -1 notch, reduce by one notch.

The selection of a specific notch by the above-mentioned fuzzy reasoning is based on the value of the membership function corresponding to each conditional part (in the example, C2
□, CP□, CN□) is selected by selecting the one with the maximum value. Note that this control is performed when there is no notch change suppression signal M from the notch change suppression device 13.

In this example, the first consideration was to be able to stop within the tolerance with respect to the target stopping point, and the notch was changed only if a change of ±1 notch could make it possible to stop with higher precision. , it is possible to achieve safe fixed-position stop control with few notch changes and a comfortable ride.

In the above embodiment, an example was shown in which the various arithmetic units 10 to 15 were configured with hardware, but a microcomputer may also be used for the arithmetic operations. An example of the program processing flow in this case is shown in FIG. This program consists of the vehicle speed vT, acceleration αa, and distance L to the target stop point.
This function has the function of determining the notch command N (t) based on the process.

In addition, in the above embodiment, the membership function of the ambiguous platform set for defining the ambiguous amount of stopping accuracy, which is the purpose of control, was defined as equations (5) and (6).
The present invention is not limited to this. For example, as shown in FIG.
0 Km/h) or more, the circuit stops from the target point ○ to Q'
Aim for point Q, which is 2 meters (for example) in front of you, and the speed is ■. It is also possible to change the score in stages such that when the score is below, the goal is 0 points.

In the fuzzy inference in the above embodiment, the notch increase/decrease is ±1 notch, but it goes without saying that more notch changes may be added to the selection range by increasing the number of control laws.

〔Effect of the invention〕

As described above, according to the present invention, after the vehicle passes a predetermined position before the target stop point, the brake control start determination operation is periodically performed to determine whether the brake control operation start point has been reached. After reaching the brake control start point, the brake control command is periodically determined according to the state of the vehicle, and if the current brake control command yields a preferable control result, the control command is issued. Since the speed of the vehicle is controlled to maintain the speed as it is, the number of times the control command is switched is reduced compared to the conventional speed pattern following method, and the vehicle can be driven comfortably to the target position.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a conventional fixed position stop control device, FIG. 2 is an operation explanatory diagram showing its speed pattern, FIG. 3 is a block diagram showing an embodiment of the present invention, FIG. FIG. 5 is a diagram for explaining the operation, FIG. 6 is a processing flowchart showing another embodiment of the present invention, and FIG. 7 is a diagram showing a speed pattern in still another embodiment of the present invention. . 1: Speed generator, 2': Speed acceleration calculation device, 3':
Remaining distance calculation device, 4: Ground element, 5: Ground check hoist, 9 Ni brake device, 10: Stop error calculation device, 11 Ni Brake start command device, 12Z. 12P, 12N: Ambiguous amount calculation device, 13: Notch change suppression device, 14: Control notch calculation device, 15 Brake command calculation device. stem ward

Claims (1)

[Claims] 1. In an automatic vehicle control method in which a control command is determined according to the state of the vehicle and speed control is performed to stop the vehicle based on the control command, after the vehicle has passed a predetermined position before the target stop point. , performs a brake control start determination operation that determines whether the vehicle has reached a state where brake control operation should be started while predicting the stopping error that would occur if a predetermined brake control command was given at that time. After the brake control start state is reached, the brake control command is determined periodically according to the vehicle condition, and the brake control command is determined without changing the current brake control command. A control error predicted when the control command is held and a control error predicted when the control command is changed by a predetermined amount are compared by fuzzy reasoning, and one control command to be given to the vehicle is selected based on the result. An automatic vehicle control method characterized in that the vehicle speed is controlled in accordance with the brake control command.