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Simulink Exercise Part II:
You are given a set of time-series data: 1.time, 2. F_exp and 3.
ys_exp(download from !"!#. Folder is named expdata.mat$% .
&exp$ denotesexperimental data
! unit step ' ange (F_spe'% was made in a pro'ess at t)2* and t
epro'ess was run till t)2**. +imestep was *.1s.!s a pro'ess
engineer, your o is to re'over all t e transfer fun'tionparameters
and to 'ome up wit t e “optimal” transfer functions.
You may assume 1 st order form for valve and pro'ess and a time
delayfor sensor.
+ erefore, we need to nd / varia les (tau_v, 0, tau_p and t
eta%alve : tau_v = unknown: + erefore, v ) 1 (tau_v.s 4 1%.
5ro'ess: K=unknown, au_p=unknown : + erefore, p )
0(tau_p.s41%
ensor: t!eta = unknown : + erefore, s ) exp6(-t eta.s%.
teps to follow:
1. 7ontinue from previous 'lass examples. 8pen up
simulin0pro'ess diagram
2. ave as anot er name now (e.g. pro'ess_opt% in t e same
folder.3. o to all t e lo'0 diagrams. 9epla'e t e parameters wit t
e
un0nowns de ned a ove. ( ote: at t is point you will e una leto
run t e simulin0 model sin'e t e varia les are unde ned%.;veryt ing
else 'an remain t e same
/. 7reate a main_opt.m. ?e ne glo al varia les : varia les t at
are glo al s ould e time,
F_exp, ys_exp (note: exp is added to denote experimental data.
%and any varia le t at is o tained in t e fun'tion le ut needs
to
e used in t e main le. see elp glo al.@. Aoad t e experimental
dataset (see elp load%B. ow if you run t e main_opt le and type w
os you s ould see
t ree varia les (time, F_exp ys_exp%.C. set initial 'onditions
for t e set of varia les. Aet x* ) D> B < @E.
ote: we do not 0now t e optimal values at t is point so we
needsome set of starting values. x is t e ve'tor of Dtau_v, 0,
tau_p andt etaE and * indi'ates initial point.
1*. we are now ready to use t e 'ommand &fminsear' $. + is
isa gradient-free optimi ation algorit m (nelder-mead% t at ta0es
astarting point, ' e'0s t e sum of sGuared error (sse% and furt
eradvan'es to a etter point and 0eeps advan'ing till t e sse'annot
e improved any furt er.
11. type elp fminsear' to 0ey in t e syntax
8/16/2019 Simulink+Exercise_part_II
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12. #n t e syntax, t e last argument s ould e options13. in t e
line a ove t e fminsear' 'ommand type t e line,
options)optimset(H%. +ype elp optimset to learn w at t e Hs ould
e. 8n'e of t e t ings to ll in is t e display iterationoption.
1/. you will now also need to 'reate a fun'tion le (name
itopt.m%1. ote: you don$t ave to 'onsider t)* to 2* sin'e t e
stepwas made at t)21.
2@. type &return$ at t e end of t e fun'tion le2B. 5lot and
overlay t e varia les in t e main le. !lso plot t e
residuals (w at are residualsM % . ' e'0 ow t ey 'ompare.2C. ow
you s ould e ready to run t e les. 9emem er to run
t e main_opt le and it will automati'ally 'all t e opt le and t
epro'ess_2 les.
3*. You s ould e a le to see t e display of iterations in t
e'ommand prompt
