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Benchmark damadics
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BENCHMARK SIMULATION MODEL IN BENCHMARK SIMULATION MODEL IN SIMULINKSIMULINK
MichaMicha BartyBarty, , Salvador Salvador de las de las HerasHeras
DAMADICS DAMADICS Workshop Workshop ROBUST METHODS IN FAULTROBUST METHODS IN FAULT
DIAGNOSISDIAGNOSISHULLHULL
January 25, 200January 25, 20022
What was done?What was done? What model?What model? Positioner modelPositioner model Pneumatic chamberPneumatic chamber ValveValve End remarksEnd remarks
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
What was done?What was done?Concise progress report between September and December 2001Concise progress report between September and December 2001
Improving friction model with stick slip effect Tuning control valve model flow coefficient function Setting structure of handles for DAMADICS BENCHMARK ACTUATOR
LIBRARY Preparing draft proposal of DAMADICS BENCHMARK ACTUATOR
LIBRARY principles and structure
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
What What modelmodel??
Model of actuator consisting of: positioner, pneumatic motorand control valve
Model based on physical phenomena description Created with many simplifications For better use, model general structure reflects hardware of actuator i.e.
consists of : Positioner, Pneumatic Servomotor and Control Valve submodels
Model does not contain: plant, installation and controller modeles Integrated with DAMADICS BENCHMARK ACTUATOR LIBRARY as a
core of Actuator (Act) block Suitable for first phase of testing FDI algorithms prior to testing using
process data and pilot industrial implementation Upgraded model version introduced in Lisbon Vacation School
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
What isWhat is to be to be simulatedsimulated ??(An assembly of(An assembly of positionerpositioner, pneumatic servomotor and control valve), pneumatic servomotor and control valve)
Actuator structure
Actuator assembly and installation
F
P2P1
x
CV Positioner
X
V1 V3V
V2
ps
F
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Actuator model
Actuator Actuator
Actuator general block diagram
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Vector of faults f is used in DAMADICS BENCHMARK ACTUATOR LIBRARYVector f entries are not further shown in this presentation with some exceptions
Actuator
CV
FP1
P2XT
f
Actuator model (3 constituents)Actuator model (3 constituents)Model was tuned for simulation of power station boiler
Positioner Pneumaticservomotor
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Is model tuning possible from real dataIs model tuning possible from real data??KvKv function reconstructionfunction reconstruction
Estimating Kv value of valve from actuator 3.
Kv va lue (31 Octobe r 2001)Ste a m boile r a ctua tor 3
020406080
100120140160
0 20 40 60 80 100
Valv e c lo s ing rate
Kv
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
The valve plug travel range of the of control valve may not be sufficiently enough for proper Kvfunction reconstruction.
Extrapolation technique may be used for example for Kv approximation
ActuatorActuator modelmodelPower station boiler water supply simulation (results)
Flow F
Valve travel X
Set point value
time [s]
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Positioner Positioner Input filter structure and properties
Rejection of mains disturbances(immunity against EMI)
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Positioner Positioner Proportional controller
Classical solutionBooster drives electro-pneumatic transducer
SP
CV
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Positioner Positioner Electro-pneumatic transducer
Significant non-linearity and asymmetry
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Positioner Positioner Feedback path
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Pneumatic diaphragm servoPneumatic diaphragm servo--motor motor ((Basic Basic equationsequations))
Servomotor hysteresis friction effect
rod down travel direction
ps
ks
Ae kd
Fn
xd
ks - spring constant kd - diaphragm constant Ae - effective diaphragm area ps - air pressure in chamber Fn - normal packing force Fp - active force Fg - gravity forceFs - spring compression force Fd - diaphragm compression force Ffv - viscosity friction forceFfC - Coulomb friction forceFvc- vena-contracta forceFdA- dAlembert forcex - rod displacementxo - initial spring compression strokem - mass of rod, valve, diaphragm
01
==
n
iiF
gvcfdspd FFFFFF ++=
gvcfdspu FFFFFF +++=
fpdpu FFF 2=
Fp Fd
Fs
FfFvcFg
Fg
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Pneumatic Pneumatic chamber chamber modelmodelBasic Basic equationsequations
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
m V V = +D DD
The classical polytropic relationship nnpp
2
2
1
1
=
p pn
=
D
D
( )1p m VnpV
=
0 0
1 tp m VdtRTV
=
Continuity law
From (1) and (2)
Assumming isothermal evolution and n=1
(1)
(4)
(2)
(3)
Pneumatic Pneumatic chamber chamber modelmodelSimulationSimulation modelmodel
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Pneumatic diaphragm servomotor Pneumatic diaphragm servomotor model model
Force balance equation
01
==
n
iiF
m
Fg
Fp
Fs Fd
x
FfvFfC
Fvc
FdA
FN
),,,,2,1,(
)sgn()()(
0
0
KvFPPxfFxmFxkF
FxFxxkFxxkF
ApF
vc
dA
vfv
fNfC
dd
ss
esp
=
=
=
=
+=
+=
=
CC
C
C
esdsvcdsNv ApmgxkkxFxkkFxsignxkxm =+++++++ 0)()()()( CCCC
ds kk >>
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Pneumatic diaphragm servoPneumatic diaphragm servo--motor motor (simulation(simulation modelmodel))
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Pneumatic diaphragm servoPneumatic diaphragm servo--motor motor ((Model Model of stickof stick--slip effectslip effect))
Hysteresis = 20%Hysteresis = 10%
1Ff
S witch
200
Friction
|u |
Abs
2
Fe xt
1v
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
VVaporapor pressure pressure lawlaw
bTapv +=log
Water vapor pressure versus temperatureWater vapor pressure versus temperatureApproximation of water vapor pressure Approximation of water vapor pressure --
temperature temperature functionfunction
pv[kPa]
T[C]100kPa
WaterWater
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS ProjectDevelopment and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
rc critical pressure ratiofor water(pressure in [MPa])
Km curve for typicalhigh recovery valve
CChokedhoked flow flow
When the fluid pressure in the cross sectional area of flow stream drops below the vapor pressure, the Bernoullis law is no more valid. The choked flow occurs. Flow is no more dependent on pressure drop.
pKQ v
=
all
vpKQ =
Bernoullis flow law
Choked flow
)( 1 vcmall prPKp =
where:
Km - valve recovery coefficientrc - critical pressure ratio of the fluidpv - vapour pressure of the liquid
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
CChokedhoked flow flow simulations simulations modelmodel
P[MPa]
Choked flow
Q[m3/h]
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
VVena contractaena contracta pressure pressure estimationestimation
Q[m3/h]
X[%]
X[%]
Pvc[MPa]
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
Control valve Control valve simulation simulation modelmodel
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
End remarksEnd remarks
Presented Simulink actuator simulation model may be used for FDIrequirements, however for common use should be provided with appropriate user friendly interface
To fulfill this requirement the DAMADICS BENCHMARK ACTUATOR LIBRARY draft proposal was developed
The model is based on physical laws that are are more convenient forfault simulation effects compared to abstractive ones
The model may be used in free phase of FDI methods verification and development
Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems, FP5 DAMADICS Project
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