SU1597729A1 - Apparatus for measuring parameters of movement - Google Patents

Abstract

The invention relates to the field of instrumentation and can be used in railway transport to measure the speed and path traveled by a locomotive. The purpose of the invention is to improve the accuracy of speed measurement. Block 4 calculations, using information about the length of the rail and the number of pulses from the output of the sensor with the driver 3 from one joint to another joint, calculates two coefficients N ₁ and N ₂ , which are received respectively in the first 5 and second 9 counters. Both coefficients are calculated for the diameter of the measuring wheel in view of its current wear. The factor N ₁ defines the time interval over which the distance traveled is calculated, and therefore, the speed is measured. The N ₂ coefficient sets the length of the path for calculating their total number, i.e. path measurements. The speed measurement is carried out by block 6, and the path by block 8. 4 Il.

Description

Output /

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WITH

tvO

with

31

This invention relates to instrumentation engineering and can be used in railway transport to measure the speed and path traveled by a locomotive.

The aim of the invention is to improve the accuracy of the velocity measurement.

FIG. 1 shows a block diagram of the device; in fig. 2 is a block diagram of the calculation of the conversion factor of the measurement time and the conversion factor of the path; in fig. 3 is a diagram of a unit for measuring the speed of movement; in fig. D - oscillogram of the acceleration process of the axle box.

The device contains an acceleration sensor 1 with a matching amplifier, a comparator 2, a pulse sensor 3 with a driver, a calculation unit 4, a first counter 5, a velocity measurement unit 6, a pulse generator 7, a path measurement unit 8, a second counter 9. Calculation block 4 contains a microprocessor 10, RAM 11, PZ U 12, input 13 and output 14 registers. The speed measurement unit 6 contains a counter 15, a register 16, a transmitter 17. A successively connected acceleration sensor with a matching amplifier 1, a comparator 3, a calculation unit 4, a first counter 5, a velocity measurement unit 6, the output of the pulse generator is connected to the second input of the first counter 5, the second output of the computing unit with the first input of the second counter 9, the second input of which is connected to the output of the sensor with the former 3 and the first input of the speed measuring unit 6, the output of the second counter 9 is connected to the input of the path measuring unit 8.

A device for measuring motion parameters operates in a sequential manner.

When the locomotive moves from the sensor 3 revolutions of the wheel, impulses come in, the number of which is proportional to the length of the track, and the frequency is proportional to the speed of movement of the locomotive

f 3-- V n, V,

(one)

f is the pulse frequency of the sensor;

Z is the number of sensor pulses per wheel revolution;

L -; c-meter circle Katani wheels;

p - number of impulses per meter

If

Circle Katani wheels.

five

0

five

0

45

50

55

The number and frequency of pulses at constant paths and speeds change as the locomotive wheel wears. The pulses of the sensor 3 are fed to the first input of the velocity measuring unit 6 and the second input of the second counter 9. On. the second input of unit 6 receives pulses from the interval T of the time for measuring the speed of movement. The measurement time interval is formed by a counter 5 with a variable fill factor, KoTopbtfi is set equal to the coefficient N. The recalculation of the measurement time calculated by block 6 during the correction period. The pulses of the generator 7 arrive at the second input of the counter 5 and fill it up to a value equal to the coefficient N of the recalculation of the measurement time. After filling the counter 5, it will zero and the cycle of its filling will repeat -. is. At the output of the counter 5, form-, with pulses, the period of which is equal to the interval, the measurement time.

The signal arrives at the second input of the counter 15, which counts the number of pulses received from the output of the wheel speed sensor 3 during time Tj, 3, and writes the speed code to the output register 16, which then goes through the transmitter 17 to the first output of the device, and the counter 15 and register 16 with the arrival of the subsequent impulse Tud is zeroed.

The measurement of the path of movement is carried out as follows.

The first input of the second counter 9 receives the value of the coefficient code Nl of the recalculation of the path of motion, the calculation of which is carried out during the correction period of the device. N is numerically equal to the number of pulses of sensor 3 per unit length of the path traveled.

Counter 9 counts the number of pulses from the output of sensor 3, and upon reaching the number N, forms a transfer pulse at the output and starts counting with zero. Thus, the counter 9 generates one impulse for each unit of the traversed path. These pulses enter the path measurement unit 8 at the input of a sum counter, which calculates the distance traveled. The code of the distance traveled through the transmitter enters the second output of the device.

515

When the locomotive moves along rails of known length, the signals of the beginning and end of the rail are separated by the comparator 2 from the acceleration process measured by the acceleration sensor 1, which is mounted on the axle box of the locomotive. As an example in FIG. 4 is an oscillogram of the recording of the acceleration process of the axle box measured by the acceleration sensor. The oscillogram clearly distinguishes bursts during the passage of rail junctions, t, .e. the beginning and end of the rails. For

Ell

extracting the signal of the beginning and end of the relay, but equal to 1 s. Optimal value

The comparator is tuned to the threshold voltage level, which is shown on the oscillogram by a line. When the sensor output 1 is higher than this level, the output of the comparator is an impulse corresponding to the beginning and end of the rail.

After switching on in the block 4 the correction mode on the front of the first pulse arriving from the transmitter of the comparator 2, in block 4 the counting of the turns of the speed sensor starts, on the front of the second the count ends. Based on the result of the calculation in block 4, the coefficients N, N are calculated using the formulas obtained from the following relations.

Pulse Frequency of Wheel Turn Sensor

the interval is obtained on the basis of practical experience, as well as on the basis of known data. For example, in a known device, the time interval measuring 20 speeds is 1 second. An increase in TU several times leads to a loss of information on short sections of the path, as well as an increase in measurement error, especially when the scientific research institute changes its speed, since the device measures the average speed in the interval T, which differs from the speed in a shorter time. time inside this interval 30 la T

W3 "

Decrease interval

chzm

at

several times leads to obtaining redundant information, as well as an increase in measurement error, especially at low speeds.

f- - Nr T

 MZLD

where N is the number of pulses of sensor 3 during the time interval for measuring the TIEGU,

then the measurement time interval Tj

derived from relations (1) and (2) is defined as

 Nr

needle p. V

The number N of the wheel speed sensor pulses is chosen equal to the value of the tekFJ of the speed of movement

; t-Ukm / h 3,6V ---,

(four)

Then the interval Tj, calculated from formulas (3) and (4) takes the form

T -

NZM II

depends

to from

numerical

for example, when n 3, (

This is calculated by the scientific research institute according to the formula

in block 4

t 1 - isll

  calculate

P" :-

LP

(6)

where N- are the turns of the pulse sensor along the length Lp, the nominal value of which is recorded in the block 4 permanent memory.

The optimal value of the interval T of the speed of movement is chosen on the basis of the specified requirements for the frequency of arrival of the results of measuring the speed of movement of the locomotive. The most optimal interval T

Ell

approximately equal to 1 s. Optimal value

interval obtained on the basis of practical experience, as well as the outcome of known data. For example, in a known device, the time interval measuring 20 speeds is 1 second. Increasing TU several times leads to a loss of information on short sections of the path, as well as an increase in measurement error, especially when the scientific research institute changes its speed, since the device measures the average speed over the interval T, which differs from the speed in a shorter time. inside this interval t

W3 "

Decrease interval

chzm

at

35

several times leads to obtaining redundant information, as well as an increase in measurement error, especially at low speeds.

To calculate the optimal interval of a TUZIL with a given accuracy, expression (5) can be represented in the following form:

SLL

P "

(7)

Where

45

the coefficient of increase in the accuracy of the calculation is chosen from the series K (1, 10, 1000). At the same time, the ratio number

n is calculated from

P

 S.K.

(eight)

where c is chosen to be close to or equal to 3.6.

5Q As the locomotive wheels wear out, the number of sensor pulses per wheel revolution increases, and the interval T calculated by block 6 using formula (7) decreases.

55

The error of the interval T is associated with the determination of the number of pulses of the wheel speed sensor on the reference rail length. When the number of pulses n per meter of wheel revolution is 4,

the number of pulses at length 1, rail 25 and will be

NP t .. p, 100 imp. , (9) The relative error of determining the interval due to the discreteness of the account in this case is equal to:

100% 1%

. (ten)

 Np. Np

where 4Np ± 1 mm is absolute coverage due to the discreteness of pulse counting at the beginning and end of the rail.

, imp „When K. 10 p, 36 --- ,. 900 imp, the relative error of the interval T ,,, is already

 0.1%.

Thus, the error in the calculation of the interval Tm by an increase in the values of n and K. decreases. A partial decrease in the error is achieved by an averaging of T, according to the results of several counting knobs N., the interval formation time is carried out by the counter 5, in block 4 the coefficient N of the conversion of the measurement rate is calculated, equal to the number of generator pulses 7 during the interval Tc5l

t - t f111;

 I 1 - ISM -r -,

Where f is the oscillator frequency value /. Substituting in (11) (5) and (6), get

", 4 f g (12)

The calculated value is fed to the storage in output register 14 of block 4. From block 4, the coefficient N is fed to the first input of counter 5.

The path recalculation coefficient N is calculated on block 4 using the formula

0

g IT

(13)

five

ABOUT

where m is the unit of measurement of the path.

The value of the coefficients N ,, comes in the register 14 of block 4.

Claims (1)

Thus, the movement parameters of the locomotive are measured in accordance with the calculated coefficients M, whose values are proportional to the wheel diameter. Invention Formula A device for measuring motion parameters containing a pulse sensor with a driver, a pulse generator, a counter, a computing unit, speed calculating units and paths whose outputs are the first and second outputs of the device, characterized in that equipped with an acceleration sensor and a matching amplifier, a comparator, a second counter, and the output of the imager is connected to the first input of the speed measuring unit, to the second input of the second counter and the first input of the unit and the second input of which is connected to the acceleration sensor through a matching amplifier and comparator, the first output of the calculation unit is connected to the first input of the first counter, the second input of which is connected to the output of the pulse generator, and the output to the second input of the speed measuring unit, the second output of the calculation unit connected to the first input of the second counter, the output of which is connected to the input of the unit. measuring the path. 2 The process of acceleration Monemta proko nor joints log Jp- ZSn FIG. five Freak cfloSamuiuMa nanaaratoa