Vol.1, No 10, 2003 pp. 1339 - 1346
UDC 621.87:519.219
EXTERNAL EXCITATIONS AND DISTURBANCES
WITH BUCKET WHEEL EXCAVATORS
AS NON-LINEAR AND RANDOM FUNCTIONS
Goran Petrović, Vinko Jevtić, Melanija Mitrović, Zoran Marinković
University of Niš, Faculty of Mechanical Engineering, A. Medvedeva
14, 18000 Niš
Abstract. On the example of the driving system of the boogie wheel
on the concrete bucket wheel excavator, the paper analyses external effects
which stem from the electric motors and resistance to motion of the spoons.
The curves of moments of starting three-phase asynchronous cage and slide-disc
electric motors are considered and analytically modeled as non-linear functions
of the angular velocity M = f (?). Since the resistance of digging is not
uniform, due to the alternating smaller number of spoons engaged with the
non-homogeneous mass of ground, and different pressure angles, it is modeled
as a random function of time. Graphical interpretation is also provided
for the given disturbances. The knowledge of the more real changes of these
disturbances enables a more adequate design of the bucket wheel excavator
which will be of more use in exploitation.
SPOLJAŠNJE POBUDE I POREMEĆAJI KOD ROTORNIH
BAGERA KAO NELINEARNE I SLUČAJNE FUNKCIJE
U radu su na primeru pogonskog sistema radnog točka konkretnog roto bagera
analizirani spoljašnji uticaji koji potiču od elektromotora i od otpora
kopanju kašika. Razmatrane su i analitički modelirane krive momenta puštanja
u rad trofaznih asinhronih kaveznih elektromotora kao nelinearne funkcije
ugaone brzine . Pošto je otpor kopanja neujednačen, zbog naizmeničnog
manjeg broja kašika u zahvatu sa nehomogenim masivom tla i različitim uglovima
zahvata, on se modelira kao slučajna funkcija vremena. Za navedene poremećaje
data je i grafička interpretacija. Poznavanje realnijih promena ovih poremećaja
omogućava adekvatnije proračune roto bagera koji će biti više iskorišćeniji
u eksploataciji.
