about application of radar technology in rail transport for the...

978-1-5090-1081-3/17/$31.00 ©2017 IEEE

2017 International Siberian Conference on Control and Communications (SIBCON)

About application of radar technology in rail

transport for the diagnostics of the condition of the

rail track and rolling stock components

V. S. Potylitsyn, G. Y. Shaydurov, E. A. Kokhonkova.

Research Laboratory of Iridy

Siberian Federal University

Krasnoyarsk, Russia

[email protected]

Abstract — This article describes the radar (RL) method for

extraction information about the defects of the rail track by

registering their own natural oscillation frequency (NOF) rail

span between two sleepers.

Keywords — natural oscillation frequency, radiolocation, defect,

defect detection, nondestructive inspection.

I. INTRODUCTION

The role of non-destructive control and diagnostics on

modern railways is extremely urgent, so the entire network of

railways of Russia set up special centers non-destructive

control, equipped with more than 5,000 of removable and

mobile ultrasonic testing equipment, which employ

exploitation today approximately 10,000 operators, and

periodicity control range from 2 to 6 times per month.

However, each year allowed 100 - 150 breaks, often leading to

outright trains.

The basic means flaw detection at the railway transport are

the electromagnetic and acoustic flaw detectors. The

advantage is the possibility of electromagnetic flaw detectors

conducting contactless control while moving at a speed

exceeding 80 km per h, but the use of eddy current principle of

building electromagnetic flaw detectors does not allow to

detect rail defects, the depth of their occurrence over 8 mm.

The advantage of acoustic or ultrasonic flaw is their high

penetration ability, which determines its use as the main means

of flaw detection of the track. However, ultrasonic flaw

detectors have a serious drawback - it is a necessity of physical

contact between the piezoelectric transducer and controlled

fragment rail [1,2]

The method is to obtain information about the defects of

the rail fragments by registering their own frequency

mechanical vibrations of the rail span between the sleepers.

The natural frequency of oscillation of the rail depends on the

physical parameters such as density and elastic modulus of the

material, geometric shape, the presence of irregularities and so

forth. It is obvious that the parameters of which are identical to

those fragments of rail, the natural frequency will be the same.

The presence of a defect constitutes a change in rail

structure that makes changes in the spectrum of the natural

oscillations.

II. ANALISYS OF INFLUENCE DEFECT ON NATURAL

OSCILLATION FREQUENCY OF RAIL

As a base for theoretical justification of the non-contact

method of defectoscopy, consists in registering natural

oscillation frequency rails, we use the theory of vibrations of

elastic rods. For this, rail span fragment between two sleepers

will be seen as a hard elastic rod, fixed on two fixed supports.

The expression for the natural oscillation frequency will

have the form [3]:

S

JE

l 22, (1)

where l - length of the rod; where E - modulus of elasticity; S -

cross-section of the rail; J - moment inertia of the section.

Let us give theoretical and experimental evaluation of

natural oscillation frequency rail section length l = 1.7 m,

rigidly fixed on two fixed supports. It is necessary to consider

that the rails makes the transverse vibrations in two mutually

perpendicular directions: vertical and horizontal (Figure 1).

Calculated value natural oscillation frequency obtain basic

tone, using the expression (1) for rail brand R65 in the vertical

plane - kHzXOZ 7,1 and in the horizontal plane -

HzZY 6500 [4].

Results of experiment is presented in Figure 2 as a

waveform and spectral characteristics of the process of free

damped oscillations rail taken with the radar sensors. These

characteristics make it possible confirm that the experimental

data rail natural oscillation frequency ( HzZY 6500 ,


kHzXOZ 7,1 ) are in good agreement with the calculated

values of the natural oscillation frequency.

impulse load

y

0

x

0

Fig. 1 - The transverse vibrations of the rail when the impulse of the shock

load: a - in the vertical plane u0z b - horizontal x0z.

To assess the influence of the defect on the rail natural

oscillation frequency is worthwhile to consider a change not

only the fundamental frequency in the spectrum ν0 oscillations

and offset of the vibrational modes present in the spectrum. To

detect dependence bias of vibrational modes in the spectrum of

natural oscillation frequency from presence of the defect,

experiment was conducted on bias natural oscillation

frequency defective design registration. To do this the railhead

defect in the form of artificially created washed down with

width and depth of 5mm2 5mm2, 10mm2, 15mm2, etc.

As a result, it was found that the increase in the railhead

defects per 5mm2 affects on the change rail of natural

oscillation frequency approximately 0.05%, which corresponds

to a shift of each vibrational mode spectrum at 1-3 Hz

compared with the previous value with an increase in the size

of the defect to 5mm2.

Furthermore, it was found that the defective sample

spectrum there are additional vibrational modes, whose

presence may indicate the presence of structural heterogeneity.

Hardware implementation of contactless of the flaw

detector railroad tracks in motion, which was built on the

principle of registration of microwaves modulated by

parameters intrinsic mechanical oscillations of the rail, is very

challenging, due to the effect of noise associated with the

movement of the flaw detector. The process of the radar

reading of mechanical oscillations can be represented as

follows.

At rest, the reflected signal to the receiving antenna will

have the following form:

)sin()( 0 tUtU DR , (2)

where is ω - the frequency of the radio signal; φ0 - the initial

phase of the radio signal, which is determined by the

relationship (3):

r2

0, (3)

Where is r - the distance from the source to the the object of

research; λ - the length of the radio wave.

Fig. 2. Characteristics of the process of free rail oscillations.

a - free rail oscillations waveform, b - spectrum of free oscillations of the rail

If the control object oscillates with frequency w, then in

accordance with the periodic change in the parameter r, in

equation (3) will change parameter phase φ0. We rewrite the

expression (3) for this case:


)sin()( 0 tUtU DR, (4)

Where

)sin(2 0 tr - parametric dependence of the

radio signal of the phase change of the vibrational bias the

surface of the rail; )sin(0 trr - offset the irradiated

surface of the rail; φ0 - the stationary part of the phase shift;

- frequency vibrations of the rail.

Then the radio signal to the receiving antenna is described

by the expression:

))(2

sin()( 0

rtUtU DR

(5)

механическая

импульсная

нагрузка

3 3 3

1

2

86 7

4

9

10

11

5

50см 50см

12

Fig. 3. Experimental set. 1 - a device to simulate the impact of interaction

of wheel and rail; 2 - rail; 3 - fixed support; 4 - radar; 5 - receiving-

transmitting antenna; 6 - the transmitter; 7 - receiver; 8 - an amplitude

detector (PD); 9 - ADC; 10 - a spectrum analyzer; 11 - Display unit 12 -

defect.

III. THE IMPLEMENTATION FLAW RADAR FLAW ON

RAILWAY TRANSPORT

Consider a system embodiment inspecting components and

rolling nodes based registration natural oscillation frequency

radar method (Fig. 4.a). In this case, when a train is moving,

there is a radar scan of rolling stock components (wheelsets,

axle nodes, automatic couplers, etc.) and the selection

spectrum natural oscillation frequency, which is compared

with a reference spectrum of defect-free sample and a decision

on the defectiveness-inspected node.

Fig. 4.b shows a block diagram of a contactless radar

works for nondestructive testing defectoscope track in motion.

When there is a train movement acoustic noise in the

spectrum, which will be attended by natural oscillation

frequency rail. During the movement of the vibrating surface

of the rail irradiated radar microwave signal. The reflected

signal from a vibrating surface will contain information about

the parameters of the rail oscillations.

Currently, non-destructive testing methods, based on the

obtain information about defects by analyzing the spectral

characteristics of natural oscillation frequency objects of

verification, are widely distributed, including railway

transport. As sensors for registering parameters natural

oscillation frequency used usually microphone assembly

(MA). MA disadvantage is that they have a low directivity,

and therefore exposed to external acoustic noise.

Fig. 4. Radar contactless defectoscopy method, a - rolling stock node with a

fixed installation, b - the installation of rails on moving rolling stock.

This allows you to make use them only approximately an

integral assessment of the technical condition inspected node,

but makes it impossible to reliably detect defects specific

details. Using radar sensors allow for rapid directional remote

scanning, which will allow producing selective control of parts

and node of rolling stock in motion at high speed.

In addition to the above applications, radar technology can

also be used on the railway transport to assess the actual

condition of the ballast, the base of embankments, the

underlying surface, slopes and recesses railroad tracks [5]. For

this purpose, it can be used widespread in recent method GPR

subsurface sounding.

И

V

П Пр

Ω1, Ω2...Ωn


Fig. 5. The structural scheme flaw radar for operational nondestructive control

of rails on the move

Fig. 6 shows a block diagram of the radar flaw to diagnose

the technical condition of the railway bridge. In this case, the

natural oscillation frequency is estimated span of the bridge

when considering it as a beam rigidly fixed to fixed supports.

With radars installed continuously recorded spectrum of

mechanical vibrations of the bridge, which allows continuous

monitoring of its technical condition.

Fig. 1.7. The structural circuit of flaw radar for diagnostics of railway bridges

Fundamentally, the method is based on radar probing the

investigated area subsurface ultra-wideband (UWB) pulse

signals. Reflect on the borders soil and other environments

with different electrical properties (dielectric permittivity,

conductivity, etc.) signals are recorded receiving antenna GPR

equipment and after the hardware and software processing are

recorded in a memory in the form of radio messages, which

can be seen on the ground conditions.

Creating a diagnostic complex GPR built on the principle

of the use of UWB signals, complicated feature of UWB

technology antennas. Designing effective UWB antennas for

practical use causes serious difficulties. Nevertheless, the

creation of such systems will allow for permanent, non-

destructive examination of the operational state of the

geotechnical a carrier path of the system [6]. Based on the data

held in the opening of the railway line locations to identify

irregularities that can significantly reduce the number of such

places.

The introduction of GPR diagnostic systems based on

UWB pulse radar subsurface at the railway will significantly

improve the accuracy of the assessment of the state railway.

IV. CONCLUSION

One of the priorities in the development and

implementation of inspection tools is to minimize the human

factor in the operation of non-destructive testing systems.

Operated currently flaw does not meet modern requirements

for safety. In particular, non-destructive testing systems based

on electromagnetic methods have shallow depth study of the

rail, and ultrasonic methods are extremely big drawback - the

need to contact the sensor with the environment and as a

consequence of low productivity.

1. The given theoretical and experimental estimation

shows that is possible to implement contactless instrument

occupies defectoscopy of railway tracks, which is based on the

principle of the scanning rail by registration parametric

modulation reflected from the vibrating surface of the

microwave radio waves using the radar sensor.

2. To separate signals and noise reduction associated with

the movement of the flaw detector, proposed differential noise

compensation system consisting of multiple antennas, and is

offered to use neurocomputing algorithm for pattern

recognition and classification of defects.

3. To determine the potential of the method it is necessary

to measure the movement of noise in natural conditions,

namely, to assess the level of signal / noise ratio when setting

of the prototype on a moving part of the flaw detector, as well

as to determine the frequency spectrum of the noise associated

with the movement.

V. ACKNOWLEDGEMENTS

The authors thank the Siberian Federal University for

providing the infrastructure with the implementation of this

project. This work has been done with the support of Russian

Federal Property Fund (project № 16-07-00426) and the

Regional Science Foundation of the Krasnoyarsk Territory.

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[3] Lamb G. Dynamic sound theory / Edited by Isakovich M. A.; translate from English. Aheeva N. S.. - M .: Nauka, 1960 - 372 p.

[4] Gurvich A. K., Dovnar B. P., Kozlov V. B., Circle G. A., Kuzmin L. I., Matveev A. N., Non-destructive testing of the rails in their operation and maintenance. / Edited by Gurvich A. K.- M: Transport, 1983-318 p.

[5] Grinyov A. Y., Andrianov A. V., Bagno D. V., Multi-channel ultra-wideband short-pulse radar subsurface probing // Successes of modern electronics. - 2009. - №9. - 19-27 p.

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[7] Kudinov D. S. , Shaidurov G. Y., Non-contact nondestructive rail testing, International Siberian Conference on Control and Communications, SIBCON-2009; Proceedings, 2009. – 290-295 p.

[8] Gonorovsky I. S., Radio Circuits and signals: Textbook. manual for schools / And. S. Gonorovsky. - 5th ed.. and ext. - M .: Bustard, 2006. - 719p .

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