JPS6359905B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention detects the speed of each wheel, compares it with a reference value, and controls the braking force of the wheel using the error signal obtained as a result. A method for controlling circumferential speeds of a plurality of wheels, using the maximum value of all measured wheel speeds limited to an allowable value as a reference value (slip control), and a device implementing this method. Regarding. Such methods and devices are known.

Known anti-skid devices for railway vehicles monitor the deceleration occurring at one or more wheels during a braking process and, if a settable threshold value is exceeded, release the brake of the monitored wheel for the duration of the skidding process. Loosen for a while. According to the anti-slip device, the brake opening time is determined by memorizing the running speed or wheel circumferential speed that exists at the time when a threshold value is exceeded and which exists as an electrically measured value, and the time when the wheel in question decreases along the deceleration curve. It is determined by comparison with successively measured wheel circumferential speeds until the stored value is again reached. This ensures that the braking force can only be controlled again once the wheel in question has again synchronized with the actual vehicle speed or is within an acceptable slip range. Because of this mode of operation, such anti-slip devices, which have been in use for several years, are called "V-memories".

In the V-memory skid prevention device, a common reference value for a plurality of skid prevention control devices acting on individual wheels of the driving vehicle or the towed vehicle is set to a common reference value for all measured wheel speeds of the driving vehicle or the towed vehicle. It is known to take a maximum value of , and to control a predetermined optimum wheel slip desired for transmitting maximum power on the basis of this reference value. The same applies to sideslip control, in which the predetermined reference value is taken from the minimum value of all measured wheel speeds.

However, many experiments conducted at home and abroad have shown that the results obtained by this slip or sideslip control are unsatisfactory. This is because the wheels of each driving or towed vehicle are instantaneously in approximately equal trajectory conditions, so that all wheels of the vehicle exhibit the same slip characteristics. On the other hand, the reference value derived from the maximum wheel speed therefore no longer indicates information about the actual road speed and is no longer a criterion for optimal slip control.

The object of the invention is to provide a method and a device as mentioned at the outset, in such a way that it is possible to control the slip to a predetermined optimum with respect to the actual driving speed even when all wheels of the vehicle slip unacceptably. It's about improving.

According to the present invention, this problem can be solved in the first claim.
The problem is solved by the method according to claim 1 and the apparatus according to claim 2.

"The last wheel or the last wheel to slip"
refers to the wheel that is the last of the vehicle's wheels to start slipping. Such wheels are important because the invention is based on a method of detecting the actual vehicle speed from the measured rotational speed of wheels that are not slipping. That is, once a slip condition occurs, the speed of the slipping wheel is no longer proportional to the actual vehicle speed signal. The actual vehicle speed, which serves as a reference signal for comparison with the wheel speed signal, must therefore be detected from the wheels which have not yet lost their normal amount of friction, ie have not yet slipped. When this last non-slip wheel deviates from normal friction conditions, it is called the "last wheel to slip."

In a method for detecting an actual vehicle speed or a reference signal from a plurality of wheel speed signals, the present invention provides a method for detecting an actual vehicle speed or a reference signal from a wheel that last slipped (vehicle speed = reference signal was derived from this wheel before the slip condition occurred). The technical idea is to restore the normal frictional state as quickly as possible, so that there is no need to wait for the other wheels to gradually restore their normal frictional state.

Such a concept presupposes that means are provided for increasing the frictional state at least for the last wheel to slip. Such measures are known only for locomotives and trains and involve increasing the amount of friction by adding sand or something similar to the contact surface with the track in front of the (each) wheel where the amount of friction is to be increased. conduct.

By means of a control that immediately restores the normal frictional state of the wheel that last slipped, the reference signal for vehicle speed is artificially maintained only for a very short period of time when the wheel that last slipped is in the slip condition. It will be better if you simulate it. After such a short simulation period, the speed signal of the last wheel that slipped is again available for the detection of the vehicle speed=reference signal. In other words,
The teaching according to the present invention is premised on the following recognition. For optimal slip control, for example with a slip of 0% to 10%, it is necessary to always have information about the actual running speed. The road speed detection is carried out via the detection of the rotational speed of one or more wheels that are always slipping, so that if all wheels are slipping, the road speed detected in this way is incorrect. In order to recover the necessary information about the actual driving speed as soon as possible, according to the invention, the last slip is detected, for example by countermeasures such as pulsed or continuous opening of the brakes of the wheels in question (slip control). Unacceptable slippage of the wheels is eliminated as soon as possible. Until the last time an acceptable slip condition (e.g. 0% to 10% slippage) is re-established in the wheel that has slipped, the reference value is provided artificially, for example by a capacitor, which capacitor It constantly remembers the measured driving speed and is discharged via a resistor in the event of an unacceptable slippage of the associated wheel, the discharge curve of the capacitor then corresponding to the course of the driving speed of the braked vehicle. ing.

If the last non-slip wheel returns to an acceptable slip range within the abovementioned period until the last slippery wheel regains an acceptable slip condition, the reference value is taken from this wheel and Countermeasures on slippery wheels are over.

Embodiments of the present invention will be described below with reference to the drawings.

In the time diagram shown in Figure 1, the four-wheeled vehicle is
After the time t ₀ , each individual wheel 1 to 4 is braked, so that in the case of slip control according to the prior art, each individual wheel 1 to 4
It is assumed that the rotational speed curve shown for It is further assumed that wheels 1 to 4 exhibit unacceptable slippage at different times t ₁ to t ₄ . If one of the four wheels 1 to 4 has not yet slipped, then at time t ₄
All measured wheel speeds V1 to V up to
The maximum value selected in step 4 corresponds to the actual linear speed (travel speed) of the vehicle on the ground and is used to derive the correct traveling speed reference value for controlling the amount of slippage of the slippery wheels. can. In the case of railway vehicles, the optimum amount of slip to be controlled is a slip amount of up to 10%, in contrast to a 0% slip, with which the brakes are continuously vented and re-aired, and therefore the braking A reduction in output is prevented.

But as soon as the last wheel, e.g. 4, starts to slip, the measured maximum value of the wheel speed no longer corresponds to the actual driving speed, so that the reference value taken from it has an error, Moreover, the wheel slip becomes increasingly large after time _t4 .

In contrast, according to the method according to the invention shown in _FIG .
4 has an unacceptable amount of slippage.
At this time, wheels 1 to 3 have already entered the slip state, and therefore, at time _t4 , it is detected that wheel 4 (the last wheel that has not slipped) has entered the slip state. Depending on this detection, the braking force is reduced as quickly as possible at the last wheel that slipped and the frictional force of the last wheel that slipped is quickly restored by countermeasures such as pulsed or continuous sanding. Ru. This causes the rotational speed of the wheel 4 to change in the period t ₄ to t ₅ in FIG.
The course of the pear shape shown within occurs. wheel 4
An empirically determined deceleration of, for example, 2.5 m/S ² is used as an evaluation criterion to detect that an unacceptable slip has occurred. It corresponds to
The period △T = t ₅ - t ₄ is the "last wheel slipping period"
It is called. As is clear from FIG. 2, the wheels 4 are
A slip-free or acceptable slip condition is restored at time t ₅ so that after time t ₅ the measured maximum value of all wheel speeds (in this example the rotational speed of wheel 4) again corresponds to the actual driving speed. The reference value corresponding to the speed and therefore taken from this maximum value is
Again ensuring the desired optimum slip control. During the period ΔT during which the measured maximum value of all wheel speeds does not correspond to the actual vehicle speed, the curve shown in dashed lines in FIG. generated by a capacitor.

Another wheel 1 to 3 sliding for a period △T
If one of the wheels restores a slip-free or acceptable slip condition, for example due to improved track or track properties, the countermeasures introduced at the wheels 4 are immediately terminated and the maximum speed value is then The non-slip wheel speed value, which is , is used to derive the reference value.

The device according to the invention shown in FIG. 3 is used for carrying out the method explained in FIG. 2 for optimum slip control and comprises a series of known parts:
These parts will only be briefly explained.
The following items belong to this category: That is, a slip control device R1 to R4 for each one of the four wheels generates an electrical output signal V1ist to V4ist corresponding to the circumferential velocity of the wheel 1 to 4 in question and is coupled to each one of the wheels 1 to 4. speed sensor G1 to G
4. Elements F connected to the outputs of the sensors G1 to G4 in order to take out the reference value _VSOII , the output terminals of which produce error signals ΔV1 to ΔV4 which are supplied to the respective control devices R1 to R4 and which output the reference value
V _SOII and one signal V1ist or V4ist respectively
comparator elements K1 to K4, which are supplied with the same voltage, and actuating elements MV1 to MV4 which produce an acceleration or deceleration in the wheels 1 to 4 forming the control section and which are controlled by control devices R1 to R4. The slip control circuit according to FIG. 3, which has been explained so far, corresponds to the known technology mentioned at the beginning.

According to the invention, the output terminals of the comparison elements K1 to K4 also lead to a selection circuit L, whose four output terminals L1 to L4 each lead to one logical combination element V1 to V4, for example OR
These logic coupling elements are respectively arranged between a control device R1 to R4 and the associated control device MV1 to MV4. The logic coupling elements V1 to V4 make it possible to control the operating elements MV1 to MV4 by means of the output signals of the associated control devices R1 to R4 and the output signals of the selection circuits L on the associated output terminals L1 to L4. .

Furthermore, the selection circuit L has an activation input terminal which is activated when the maximum value of all measured wheel speeds V1ist to V4ist falls below the aforementioned slip evaluation criterion, for example 2.5 m/ ^S2 . ,
It is controlled by element F at time t ₄ (FIG. 2).
After the start-up has taken place, the selection circuit L selects the four wheels 1
It is detected which of all the error signals ΔV1 to ΔV4 is the last one to have caused a slip, that is, which one of all the error signals ΔV1 to ΔV4 is the smallest.
Depending on this detection, the selection circuit L applies a control signal to the actuator corresponding to the last wheel that slipped, and then this and only this actuator determines the tolerance that has occurred on the wheel 4 that last slipped. Appropriate countermeasures are initiated at the wheel that last slipped until the inevitable slippage is eliminated (time t ₅ according to FIG. 2).

The circuit-technical details of the selection circuit L are a matter for those skilled in the art and therefore do not need to be explained in detail within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a time diagram showing the progression of wheel circumferential speed before and after the wheel that finally slips starts to slip in a vehicle in which known slip control is performed;
FIG. 2 is a time diagram showing the progress of the circumferential speed of a wheel of a vehicle controlled by the present invention before and after the wheel that finally slips starts to slip, and FIG. 3 is a time diagram showing the process of the present invention for a four-wheeled vehicle. FIG. K1 to K4... Comparison element, L... Selection circuit, MV1 to MV4... Operation section, R1 to R4... Control device, V1 to V4... Logical coupling element.

Claims (1)

[Claims] 1. Detecting the speed of each wheel, comparing it with a reference value, and controlling the braking force (slip control) of the wheel in question based on the error signal obtained from this comparison. In a method for controlling circumferential speeds of a plurality of wheels of a railway vehicle, when at least one wheel does not show an unacceptable amount of slip, the reference value is limited to an allowable value of all measured wheel speeds. When all wheels have unacceptable slippage,
A method for circumferentially surrounding a plurality of wheels of a railway vehicle, characterized in that the braking pressure is rapidly reduced at the last wheel to slip, and the frictional force between the last wheel to slip and the running track or rail is increased. How to control speed. 2. Measuring sensors G1 to G4 are provided for detecting the speed of each wheel, and a device F is provided for generating a reference value from the maximum value of all measured wheel speeds, which is limited to an admissible value. In addition, comparison elements K1 to K4 are provided to compare the measured speed with a reference value. In the device for controlling the circumferential speed, a selection circuit L is provided,
The input side of this selection circuit is the comparison element K1 to K
4, one control device R1 to R4 is provided for each wheel, the inputs of which are each connected to the output shaft of one comparison element, the output of said control device being The sides are each coupled to one corresponding selection circuit output side via one coupling element V1 to V4, said coupling element V
The outputs of 1 to V4 are each connected to one corresponding operating element MV1 to MV4, and the reference value generating device F has the function of generating a reference value from a maximum value limited to an acceptable value. In addition, it has a function that generates a detection signal when all wheels have an unacceptable amount of slip and the deceleration of all wheels falls below the standard deceleration.
When the detection signal occurs, the detection signal is supplied to the selection circuit L, which sends a control signal to the output corresponding to the last wheel that slipped, and based on this, the selection circuit L sends out a control signal to the output corresponding to the last wheel that slipped. A circumference of a plurality of wheels of a railway vehicle, characterized in that an operating section is provided for reducing the braking force on a wheel that has slipped and for increasing the frictional force between the wheel and the running track or rail. A device that controls speed.