when i run frestimate(mdl,io,in) , it comes out following warnings, what can i do~

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??? Error using ==> frestimate>LocalCheckDataTypeAndSampleTime at 532
In "frestimate(modelname,op,io,in)", the input signal "in" is a
frest.Sinestream signal which has parameter values for "Frequency" and
"SamplesPerPeriod" such that it inherently has multiple sample times.
Using such an input signal requires that samples rates belonging to the
Simulink signals where your linearization input and output points are
located are either continuous or fixed in minor time step and the
linearization I/O io(1) does not satisfy this requirement. Consider either
changing the sample time of Simulink signal where io(1) is located to
continuous sample time or using frest.createFixedTsSinestream utility to
create a sinestream signal that has a single sample rate.
Error in ==> frestimate>LocalSetupForSimulation at 379
isVarTs = LocalCheckDataTypeAndSampleTime(table,in,ModelParameterMgr);
Error in ==> frestimate at 94
[parammgr,SimulationPackage] =
LocalSetupForSimulation(model,io,op,in,numout,opts);

回答(2 个)

Arnaud Miege
Arnaud Miege 2011-4-26
The error message suggests two things, have you tried them?
  1. Change the sample time of the Simulink signal where io(1) is located to a continuous sample time
  2. Use frest.createFixedTsSinestream to create a sinestream signal that has a single sample rate
Without seeing the model and the code, it's difficult to be more specific.
HTH,
Arnaud
  5 个评论
James Zhao
James Zhao 2011-4-27
Thank you for your advice, i'm working on it,i use following codes:
>mdl='anynch'
>io=getlinio(mdl)
>linsys=linearize(mdl,io)
>in=frest.Sinestream('Frequency',logspace(-1,1,50),'Amplitude',1e-3)// or >in=frest.createFixedTsSinestream (5e-6)
>sys=frestimate(mdl,io,in)
before i type in such codes, i've already set 'input''output''openloop' in pid controller model.
Arnaud Miege
Arnaud Miege 2011-4-28
Can you explain about the I/O points? Do you mean the inputs and outputs of the PID controller? Why openloop? What are you trying to get the frequency response of? Shouldn't the I/O points be at the top-level of the model, e.g. w* and w? Also, are you aware that you are using a discrete sample time of 1s for your PID controller, whereas your electrical model has been discretized with a sample time of 1e-5s? Is that really what you intend to do?

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SimTec
SimTec 2018-2-26
Dear Miege, How can we Change the sample time of the Simulink signal where io(1) is located to a continuous sample time, I right-click on the io and I could not see any parameter related to sample time best regards
  2 个评论
MULTAN007
MULTAN007 2020-5-7
Hi,
James Zhao, TarikTech and Abdullah Al Masud, did you get the solution for this issue? I'm having same sitation. Thanks in advance for your response and time.

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