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Re: pole/zero plot for TransferFunctionModel in the control system package?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg125438] Re: pole/zero plot for TransferFunctionModel in the control system package?
  • From: Suba Thomas <subat at wolfram.com>
  • Date: Wed, 14 Mar 2012 00:36:13 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com

Nasser M. Abbasi wrote:
> On 3/12/2012 2:51 PM, Suba Thomas wrote:
>> There is an example in the v8 documentation
>> (http://wolfram.com/xid/0tp87ouzgrb3tg-gzw7gm),
>
> Thanks Suba for the example, that helps. Btw, I found a small problem
> with the code shown in the documenation: When passing it a transfer
> function with no zeros, it does not work. As in
>
>  tf = TransferFunctionModel[{{1/(s^2 + s + 2)}}, s];
>  PoleZeroPlot[tf]
>
> But will be easy to fix.

The example functions will be not be that robust and will possibly be 
easy to break. If we include the code that covers all the error checks 
and the various cases, it would distract from the purpose of the example 
(in this instance, it was to show that TransferFunctionZeros can be used 
to generate pole-zero plots.) But our hope is that it will provide a 
starting point or guideline.

>
>> and the plan is to have the built-in version in a future release.
>>
>> Thanks,
>> Suba Thomas
>> Wolfram Research
>>
>
> That sounds good.
>
> Using symbolics with numeric for control system analysis can give
> Mathematica more advantage in many cases than the 'other' toolbox out
> there which is just numeric based, but I think Mathematica control
> systems first needs much more functionality than it currently has in this
> area.
>
> What was started in V8 is a very good start and I hope much more
> functionality will be added in V9.
>
> Here is a book on the advatnages of using symbolic computation with
> control systems called
>
> "The Use of Symbolic Methods in Control System Analysis and Design"
>
> http://books.google.com/books/about/Symbolic_methods_in_control_system_analy.html?id=wQ2l0G5NVkwC 
>
>
> --Nasser

We are continuing to develop functionality in this area, and we hear you 
loud and clear. :-)

Suba Thomas
Wolfram Research

>
>> Nasser M. Abbasi wrote:
>>> I was looking at the functions in the control systems, which
>>> were added in V 8, and there seems to be a missing an important
>>> plot function to generate automatically a map of the locations
>>> of the poles and zeros for a transfer function (continuous or
>>> discrete time).
>>>
>>> Unless I overlooked it, I hope this will be added in V 9.
>>>
>>> I know I can generate such a plot myself by some extra coding,
>>> but I think a build-in function to do this would be a better solution
>>> similar to all the other useful standard control systems plot functions
>>> listed here
>>>
>>> http://reference.wolfram.com/mathematica/guide/ClassicalAnalysisAndDesign.html 
>>>
>>>
>>> Another software has this function as standard in their control
>>> systems toolbox and it is called pzmap (for googling and
>>> reference to what this command do).
>>>
>>> thanks,
>>> --Nasser
>>>
>>>
>>>
>>
>




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