vibrational stand - en

ANALIYSIS AND SYNTHESIS OF AN ELECTROHYDRAULIC CLOSED LOOP CONTROL

SYSTEM FOR THE VIBRATIONAL TESTING MACHINE

TECHNICAL UNIVERSITY OF SOFIADepartment: Hydro-aero-dynamics and hydraulic machines

Prof. dr. Ilcho AngelovDipl. eng. Nikola StanchevDipl. eng. Cvetozar Ivanov

INTRODUCTION

The article presents research and development of electro-hydraulic closed loop system for vibration test unit for the needs of the Faculty of Industrial Technology (FIT) at the Technical University of Sofia. The synthesis of the hydraulic system is accomplished in accordance with pre-set technical requirements as follows:

- spatial direction of testing, 2 axes : horizontal and vertical; - driven mass of the test object and design of the platform: m = 1500 kg;

- acceleration of the test object: a ≤ 30 m/s2;

- frequency range with acceleration a = 30 m/s2: f0 = 1 ÷ 30 Hz;

- maximum amplitude for both directions : X ≥ 3 mm;

- drive power: ≤ 30 kW;

OVERVIEW – HYDRAULIC TEST BENCHES

Simulation of road conditions

Realistic real-time simulation

6 DOF (Degree Of Freedom)

Big drive forces, up to 60 kN

Big velocities, up to1,7 m/s

Big accelerations, up to100 m/s2

Very big frequencies with big drive forces, up to 100 Hz

Big stiffness of the drive with big frequencies, independent from the driven load

ADVANTAGES OF ELECTROHYDRAULIC TEST BENCHES

HYDRAULIC DRAFT OF THE ELECTROHYDRAULIC SYSTEM

CALCULATION OF THE BASIC WORK PARAMETERS

Drive force of the cylinder…………….…………………………………………….

Active area of the cylinder…..……………………………………………………..

Work pressure of the cylinder………………………………..…………………….

Velocity of the cylinder.…………………………………………………………….

Acceleration of the cylinder…………………….…………………………………

Maximum velocity of the cylinder………………………………………………..

Maximum acceleration of the cylinder………………………………………….

Maximum flow of the pump……...………………………………………………...

c cF p .A

2 2c P AA D d4

c W ЕХСКp p p

v t x t .

a x t

v 2 fA

2 2a 4 f A

q vA

CALCULATION AND SIMULATION OF THE WORK PARAMETERS

In sinusoidal input impact in the frequency range from 1 to 12 Hz desired acceleration of 3g can not be reached!

fi, Hz a, m/s2 х, mm q, l/min v, m/s P, kW1 2 60 58 0,38 262 5 30 58 0,38 263 7 20 58 0,38 264 9 15 58 0,38 265 12 12 58 0,38 266 14 10 58 0,38 267 16 8,5 58 0,37 268 19 7,5 58 0,38 269 21 6,7 58 0,38 2610 24 6 58 0,38 2611 26 5,4 58 0,37 2612 28 5 58 0,38 2613 30 4,5 57 0,37 2514 30 3,9 53 0,34 2315 30 3,4 49 0,32 2116 30 3 47 0,3 1917 30 2,6 43 0,28 1718 30 2,35 41 0,27 1619 30 2,1 39 0,25 1820 30 1,9 37 0,24 1721 30 1,7 35 0,22 1522 30 1,55 33 0,21 1423 30 1,45 32 0,21 1424 30 1,3 30 0,2 1325 30 1,2 29 0,19 1226 30 1,14 29 0,19 1227 30 1,05 27 0,18 1128 30 0,97 26 0,17 1129 30 0,9 25 0,16 1030 30 0,85 25 0,16 10

PHYSICAL PARAMETERS OF THE HORIZONTAL CYLINDER

3g

Frequency 13 Hz and amplitude 4,5 mm

DYNAMIC BEHAVIOR OF THE HORIZONTAL CYLINDER

t, s0

S, mm

0,077 (13 Hz)

4,5

4,5

3g

3g

0

S, mm

0,033 (30 Hz)

0,85

0,85

t, s

3g

3g

3g

3g

3g


3g ► 1 ÷ 12 Hz




t, s0

S, mm2,

12,

1

0,0833 (12 Hz)

3g

0,012 tПР

2a.tA 2

22Аа t

Calculated physical parameters for horizontal cylinder in intermittent treatment with transition process in the range 0,005 – 0,013 s and restriction of the maximum flow that the servo valve can give (qmax = 60 l/min), a, m/s2 tПР, s х, m v, m/s q, m3/s q, l/min fi,max Hz

30 0,005 0,00038 0,15 0,00038 23 5030 0,006 0,00054 0,18 0,00046 27,6 41,630 0,007 0,00074 0,21 0,00054 32,2 35,730 0,008 0,00096 0,24 0,00061 37 31,230 0,009 0,00122 0,27 0,00069 41,5 27,730 0,01 0,0015 0,3 0,00077 46 2530 0,011 0,00182 0,33 0,00084 50,7 22,730 0,012 0,00216 0,36 0,00092 55,3 20,830 0,013 0,00254 0,39 0,001 59,9 19,2

PHYSICAL PARAMETERS OF THE HORIZONTAL CYLINDER

Horizontal servocylinder

Vertical servocylinders

RESULTS- 3D MODEL OF THE TEST BENCH

The design was tested with simulation at operating frequencies above 50 Hz, there is no danger of resonance (3D CAD SolidWorks)

TU – SOFIA, Department: HAD and HM

THANK YOU FORTHE ATTENTION!

vibrational stand - en

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