System Identification Dc Motor model Estimation

[aswwwa]

Hello, 

Im using Qnet DCMCT board and i'm Trying to identify the motor while it's running to use online adaptive control.

but i dont know which System identification should i use, i used ARX Recursive SID but the problem with that is  the parameters are always changing and B(z) is not the same when i compared it with the theoretical values?

any idea  ?? Help

[Kristen_K.]

With a recursive type of SysID the parameters should always be changing, that is the nature of recursion. 

Also, the likely reason the values are different from theoretical is that SysID provides a close estimation of the model than the theoretical values, this is why Sys ID is used.

You might want to take a look at the Online Model Estimation. vi in the NI Example Finder.  You can find it under Toolkits and Modules>> System Identification>> Getting Started >>Recursive Estimation. 

I hope this helps!

KristenH