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Re: [SUGGESTIONS] for OCST (perhaps I'm wrong)
From: |
Kai Mueller |
Subject: |
Re: [SUGGESTIONS] for OCST (perhaps I'm wrong) |
Date: |
Thu, 23 Oct 1997 18:15:26 +0100 |
On Thu, Oct 23, 1997 at 10:45:25AM -0500, A. Scottedward Hodel wrote:
> [name deleted]
> >
> > Hi
> >
> > I'm a guy who had to work with MatLab and preferred free
> > software, so I started to surf with Octave. I also had to use the
> > control package; initially I used Matlab's, until I found trouble, and
> > then someone recommended me to use the OCST snapshots (which I didn't
> > know, BTW :).
> >
> > Ok, as it says this is work in progress, I'm reporting some
> > slight differences I've noticed; if you already know them, sorry for
> > being repetitive :)
> >
> > ss2zp() admits an IU argument at MatLab's package. Not a guru,
> > so no idea on what it means, though it could be Input
> > Unit, or In Utero or ...
> >
> > impulse() at Matlab also admits another set of arguments,
> > being the system's state variables, the IU (still
> > don't know what it it) and a time vector. Perhaps
> > the form you offer and the one I need are easily
> > calculated one from another, but not for the
> > rookie. Then it'd just be a compatibility issue.
> >
[remaining text deleted]
Some remarks to impulse() [the same applies to step()]
and Matlab 4.x Control System Toolbox:
o the data structure "sys" to represent a dynamic system
did not exist in the Matlab 4.x CSTB.
The packed system approach in the Mu-Tools can be regarded
of a subset of the OCST system data structure. Therefore,
the arguments canot be compatible with Matlab.
o No attempt was made be compatible with Matlab's impulse().
"impulse(jet707)" for example, is short and powerful.
o OCST impulse() is equivalent to Matlab impulse() and dimpulse().
The argument list ist shorter and OCST impulse() knows about
sampling time, input and output names from the system
data structure.
o The parameter "inp" is the same as "IU" in Matlab (the input number).
o OCST impulse() tries to estimate as much as possible.
impulse() does not accept an "equally spaced time vector"
as in Matlab. The parameter "tstop" is simply a scalar value.
This allows impulse to estimate the step size automatically
if the system is continuous.
To plot the first 5 seconds of a systems impulse response
"impulse(sys, 1, 5)"
in OCST is considered to be easier to use (and safer) than
"t=linspace(0,5,200); impulse(a,b,c,d,1,t);"
If you really *need* 200 data point you can specify
"impulse(sys,1,5,200)".
--
Kai P. Mueller
Control Department (Regelungstechnik) | Phone [+49] (531) 391-3835
Technical University Braunschweig | Fax [+49] (531) 391-5194
D-38092 Braunschweig | Email address@hidden