system identification miso models

[sainath]

Hi,
   I want to know is it possible to identify the MISO and MIMO models using system identification toolkit?
   I m using fieldpoint 2010. The program is running very slow inside the fieldpoint. so is it possible to divide the program in such a way that few compuations(which are less critical)  run inside the  computer and few inside the fieldpoint?

Regards,
Sai

[Barp]

Sai,

The System Identification can identify SISO, MISO, SIMO or MIMO system with any problem (for discrete models as ARX, at least).

The sampling frequency does not matter in the algorithms. You can log the input/output signal back to the host (you can use variable for this or on you Fieldpoint) and, after you have some data, you can use the SysId to identify the model.

You could also use the Online or Recursive ARX function, which works as a point-by-point implementation of ARX. You just need to be sure that you have enough time to compute the function.

Hope this helps!

[sainath]

Hi Barp,
       Can you please send me a sample to program that explain how to identify the MISO and MIMO models(recursively) for some transfer function ?
Thanks in advance,

Cheers,
Sai

Message Edited by sainath on 05-23-2007 07:44 AM

[Barp]

Sai,

Sorry for the delay. I just noticed the reply. I have an example, but first, do you have Control Design Toolkit or, if you are using LV 8.5, the Control Design and Simulation Module ?

Please let me know and I should be able to send you a simple example using a MISO System.

Cheers!

[ruser]

Hi,

I am kind of working in the same area.. and am a bit confused. I used sys id tool kit to estimate the model and i have an arx model.

so its miso model.. and whatever i do i cant seem to figure out a way to import it to the control and simulation module library vis to get some controller design done on it... and iam really really stuck...

this is my model:

(y(k) - 1.7407 y( k-1) + 0.6236y(k-2) + 0.1782y(k-3) ) = -0.0932 u(k-1) + e(k)

where y is output , u is input and e is white noise.

i am using labview 8.5 and i have all the modules and toolkits installed..

thanks,...

ruser

[laiwei]

Hi Ruser,

 LabVIEW System Identification toolkit provides SI Convert to Models of CDT VI to convert a model you created in the LabVIEW System Identification Toolkit into a transfer function, zero-pole-gain, or state-space model that you can use with the LabVIEW Control Design and Simulation Module.

 

[ruser]

Hi,

thanks.. ok i did that step too... but still my model is in the Sys id toolkit.. how do i access it from the control design module ?

sorry.. but iam going in circles here for so long...

thanks...

ruser

[ruser]

Hi.. when i  paste that icon onto the blank vi and double click on it a windoe ( front panel ) pops out.. so what should i fill in it?

there is a system model symbol on top left side and an error and a blank space beneath it.. should i fill anything here..?

on the left hand side there is the transfer function block.. what abt here ?? shud i fill it up??

pls help..

 thanks..

ruser. 

[laiwei]

Can you offer some information about your project? Or paste your VIs on the forum, so I can take a look.

[laiwei]

I think you can perform system id on computer and perform control with identified model on fieldpoint.