JP2673263B2 - Auto brake controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic brake control device that is used in a braking system of an aircraft, a railway vehicle, etc., and executes a stopping operation at a constant deceleration.

[Conventional technology]

It is well known that an automatic brake is adopted in order to smoothly stop an aircraft, a railway vehicle, etc. at a constant deceleration. Conventionally, as shown in FIG. 6, the control device incorporated in the brake system compares the actual deceleration calculated by differentiating the wheel rotation signal by the deceleration calculation unit 61 in order to obtain a constant deceleration. In the device 62, it is compared with the set deceleration, and the difference (deceleration difference) is output to the control valve controller through the integrator 63 so that the difference becomes zero.

By the way, a road surface frictional force received by a wheel from a road surface or the like largely varies depending on a difference (sliding speed) between a wheel rotation speed and a traveling speed, and generally has a characteristic as shown in FIG. That is, when the sliding speed exceeds V ^* , the road surface frictional force starts to decrease, and the wheel rotation speed decreases at once and goes to the locked state. In addition, the road frictional force largely changes depending on whether the road surface is dry or wet. Therefore, the automatic brake control device reduces the wheel rotation speed so that the road surface frictional force provides a predetermined deceleration in the region where the sliding speed is lower than V ^* .

[Problems to be solved by the invention]

However, in the case of the conventional automatic brake control device, since the change speed of brake pressure and the change amount of pressure in the brake system are limited, the wheel rotation speed during braking is changed due to the change of sliding speed and the change of road friction conditions. Is unavoidable. When the wheel rotation speed drops, the deceleration difference calculated by the comparator 62 changes abruptly due to a sudden change in the signal, and changes in the sliding speed increase, so smooth deceleration cannot be performed. Further, the rotation deceleration of the wheels fluctuates due to the influence of skids, locks, etc., so that the brake control accuracy decreases. The use of inertial devices improves brake control accuracy but requires the addition of sensors.

An object of the present invention is to provide an automatic brake control device that improves brake control accuracy without adding an inertia sensor and enables smooth brake operation.

[Means for solving the problem]

The automatic brake control device of the present invention is an automatic brake control device that continuously and automatically controls brake pressure so that the deceleration of a vehicle body matches a preset deceleration for braking the vehicle body. A speed calculation unit that calculates the vehicle body speed from the wheel rotation speed detected by the wheel rotation speed detector, without using a wheel rotation speed detector that directly detects the rotation speed and a vehicle body speed detector that directly detects the vehicle body speed. When,
A deceleration calculation unit that calculates the deceleration of the vehicle body from the vehicle speed calculated by the speed calculation unit, and a plurality of decelerations of the vehicle body calculated by the deceleration calculation unit and a deviation of the deceleration from the set deceleration. Information is used as a control variable to configure the antecedent part of the If Then rule and the consequent part of the If Then rule is configured with the brake pressure, and the brake command pressure is calculated from the inference result of the FUZZY inference part. It is characterized by having a DEFUZZICATION operation unit for performing operations.

[Action]

The degree to which the FUZZY language control law is satisfied is extracted for each of a plurality of input information including deceleration and deceleration difference, and further, the brake pressure is FUZZY based on each degree.
Inferred. The FUZZY inferred brake pressure is a continuous value, and the FUZZY language control law contains ambiguity. Therefore, even though a complicated and expensive vehicle speed detector that directly detects the vehicle speed is not used, and without adding an inertial sensor, only the wheel rotation speed detection data is used as input information, and it is smooth and high. Accurate automatic brake control is performed.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an example of the automatic brake control device of the present invention, FIGS. 2 to 4 are graphs showing membership functions provided in the FUZZY inference unit, and FIG. 5 is its DEFUZZICATION operation. 6 is a graph for explaining a calculation procedure in the unit.

The wheel rotation signal output from the wheel rotation speed detector provided on the wheel is input to the speed calculation unit 10 to calculate the vehicle speed. The calculated vehicle speed is input to the deceleration calculator 20 to calculate the deceleration. The calculated deceleration is input to the FUZZY inference unit 30 together with the difference between the deceleration and the set deceleration (deceleration difference).

The FUZZY inference unit 30 follows the If If rule below
Make inferences.

FUZZY language rule in the antecedent part of the rule, deceleration NS means slightly decelerating (Negative Small), and NM means decelerating (Negative Medium). Each degree is obtained from the membership function shown in FIGS. 2 (1) and 2 (2). In addition, the deceleration difference PS is slightly large (Positive S
mall), the degree of which is obtained from the membership function shown in FIG. Although not shown here, PM (Positive Midium) etc. are also used in the rules.

FUZZY language rule, brake pressure in the consequent part of the rule
NS means a slight decrease in brake pressure (Negative Small), and NL means a large decrease in brake pressure (Negative Large).
Means For these, there is a membership function shown in FIG. 4, and an inference result about the brake pressure for each rule is obtained from the degree obtained in the antecedent part of each rule.

Now, assuming that the calculated deceleration is a in FIG. 2, the degree of deceleration NS is 0.25 and the degree of NM is 0.5. Further, in FIG. 3, the calculated deceleration difference is b
Then, the degree of the deceleration difference PS is 0.5.

Each rule truncates the membership function for brake pressure at the smaller of deceleration and deceleration difference. Therefore, according to the rule # 1, the inference result about the brake pressure NS becomes the shaded portion of the membership function in FIG. 4 (1), and according to the rule # 2, the inference result about the brake pressure NL is shown in FIG. It becomes the shaded part of the membership function in 2).

These inference results are input to the DEFUZZICATION operation unit 40. As shown in FIG. 5, the calculation unit 40 synthesizes the membership functions for the cut-off brake pressures NS and NL and obtains the area center of gravity point to output the brake instruction pressure d (negative). To do.

Since this brake command pressure d is output with a pressure change ΔP, it is converted into pressure P by the integrator 50 and output to the control valve controller.

Note that the deceleration calculation unit 10, the deceleration calculation unit 20, and the integrator 50
Expresses its function as a Laplace variable.

When the auto brake system is controlled by such a FUZZY control law, it is possible to know whether the deceleration difference is increasing or decreasing, and it is possible to predict a sudden change in deceleration.
Smooth deceleration with constant deceleration is possible without adding an inertia sensor.

In the above embodiment, the deceleration and the deceleration difference are used as the variables forming the antecedent part of the If Then rule.
By adding the slip speed (difference between the wheel rotation speed and the traveling speed) and the like, it becomes possible to perform more accurate automatic brake control.

[Effects of the Invention As is clear from the above description, the autobrake control device of the present invention can predict a sudden change in deceleration, etc. according to the FUZZY control law, and enables smooth deceleration at a constant deceleration without adding an inertial sensor. To Therefore, it is possible to improve the sensation during braking at a low cost.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an example of the automatic brake control device of the present invention, FIGS. 2 to 4 are graphs showing membership functions provided in the FUZZY inference unit, and FIG. 5 is its DEFUZZICATION operation. 6 is a graph for explaining a calculation procedure in the section, FIG. 6 is a block diagram showing a schematic configuration of a conventional automatic brake control device, and FIG. 7 is a graph showing a relationship between a sliding speed and a frictional force. 10: Speed calculation unit, 20: Deceleration calculation unit, 30: FUZZY inference unit, 4
0: DEFUZZICATION operation part, 50: integrator.

Claims (1)

(57) [Claims] 1. An automatic brake control device for continuously and automatically controlling a brake pressure so that a deceleration of a vehicle body matches a preset deceleration for braking the vehicle body. A wheel speed detector for detecting the vehicle speed and a speed calculator for calculating the vehicle speed from the wheel speed detected by the wheel speed detector without using the vehicle speed detector for directly detecting the vehicle speed, and the speed calculator. A deceleration calculation unit that calculates the deceleration of the vehicle body from the vehicle speed calculated by the calculation unit,
The antecedent part of the If Then rule is configured with a plurality of information including the deceleration of the vehicle body calculated by the deceleration calculation part and the deviation of the deceleration from the set deceleration as control variables, and the consequent part of the If Then rule An automatic brake control device, comprising: a FUZZY inference unit whose part is composed of a brake pressure; and a DEFUZZICATION operation unit for calculating a brake command pressure from an inference result of the FUZZY inference unit.