[Scilab-users] Optimization: First order delay and dead time TF model ID, CUTEr

[Tim Wescott]

On Fri, 2016-03-25 at 09:54 -0700, noguchi wrote:
> Hello, SCilab Users,
> 
> May I ask your help?
> 
> I still not find practical solution to minimize my object function by Scilab
> tools.
> Model: ym(n)=ym(n-1)*amp+Kpm*bmp*u(n-1-Tdm)  where n=step=1:1:500) 
> Object function: sum of square of (y(n)-ym(n))
> 
> 
> Using Excel, I made same objective funtion and minimize it by solver. The
> solution is sometimes good but some times bad. Therefore, I still need
> Scilab code to solve this problem.
> 
> May I ask how I can wrote scilab commend to solve this problem?
> 
> Thank you for your help.
> 
> 
> Y. Noguchi FODDT_ModelID_SISO_r0.xls
> <http://mailinglists.scilab.org/file/n4033859/FODDT_ModelID_SISO_r0.xls>  
> 
> 
> 
> 
> 
> 
> --
> View this message in context: http://mailinglists.scilab.org/Optimization-First-order-delay-and-dead-time-TF-model-ID-CUTEr-tp4033749p4033859.html
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> 

I don't have time to work up an example of this, but -- have you looked
at the help page for datafit?  It looks like it'll do the job (I know
how to do this with optim, but I suspect that I should have been using
datafit for a lot of that stuff).

You may want to make sure you know what you're optimizing _for_ -- I
assume that ym(0) = 0, and that amp, Kpm, bmp and Tdm are your free
parameters.

If so, you may want to revisit your problem -- Kpm and bmp are
redundant; if you're trying to optimize on both of them then you may be
confusing the optimizer.

-- 

Tim Wescott
www.wescottdesign.com
Control & Communications systems, circuit & software design.
Phone: 503.631.7815
Cell:  503.349.8432