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Transient Response of First Stage of Electrohydraulic Servovalve

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Transient response of the exit pressures of first stage of electrohydraulic servovalve

Servoactuator_data.m
% Current gain Ki
Ki=0.556
% Armature damping coefficient fth
fth=0.002
% Moment of inertia of rotor J(kg sqm)
J=5e-7
% Armature rotational angle torque gain Kth
Kth=9.45e-4
% Flexible tube rotational stiffness KT
KT=10
% Flapper length Lf(m)
Lf=0.009
% Mechanical feedback spring length Ls(m)
Ls=0.03
% Flapper limiting displacement xi(m)
xi=30e-6
% pi
pi=3.14159
% flapper diameter df(m)
df=0.0005
% Flapper nozzle area Af (sq m)
Af=pi*df*df/4
% Equivalent flapper seat material damping coefficient Rf(Nsm)
Rf=5000
% Flapper seat equivalent stiffness KLf(N/m)
KLf=5e6
% Oil density Ro (kg/Cum)
Ro=867
% Cd*(2/Ro)^0.5
Cdro=0.611*(2/Ro)^0.5
% Hydraulic amplifier nozzles N1 & N2 diameter dfn(m)
dfn=0.0005
% Diameter of return orifice N5 d5(m)
d5=0.0006
% Flapper valve nozzele 1 & 2 area AN(sq m)
AN=pi*dfn*dfn/4
% Flow Coefficients (in SI)
C12=Cdro*AN
C34=Cdro*pi*df
C5=Cdro*pi*d5*d5/4
% Spool diameter ds (m)
%ds=0.0046
ds=.004621398070216039
% Spool area As (sq m)
As=pi*ds*ds/4
% Initial volume of oil in spool side chamber Vo (Cu m)
Vo=2e-6
% Bulk modulus os oil B (Pa)
B=1.5e9
% Initial Volume of oil in the retutn chambet (Cu m)
V3=5e-6
% Spool mass ms (kg)
ms=0.02
% Spool Damping coefficient fs (Ns/m)
fs=2
% Feedback spring stiffness (N/m)
Ks=900
% Supply Pressure Ps (Pa)
Ps=2e7
% Return Pressure Pt (Pa)
Pt=0
% Servoactuator feedback gain kfb (A/m)
kfb=3
% Spool port width Omiga Omiga (m)
Omiga=0.002
% Spool radial clearance c (m)
c=2e-6
% Piston area Ap (Sq m)
Ap=1.25e-3
% Initial volume of oil in cylinder chamber Vc (Cu m)
Vc=100e-6
% Resistance to internal leakage
Ri=1e20
% Piston mass mp (kg)
mp=10
% Friction coefficient on piston
fp=1000
% Piston loading coefficient Ky
Ky=0







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