adaptive controller realization

[LucyXF]

Hi, I have an application where I have an adaptive controller, ie, some of the controller parameters change based on some online obtained data. What is the neatest way for me to realize this structure in Labview? Can I use the Symbolic "CD Construct Transfer Function Model VI" to realize this, ie, changing the value of some TF parameters when the program is running?

Thanks!

-Lucy

[SMeserve]

Hi Lucy,

Are you going to want to change the order of the transfer function?

[LucyXF]

 No, I don't need to change the order of the controller, just some parameters will be different for each iteration.

[SMeserve]

Hi Lucy,

Great, so this is super simple then.  All you have to do is change the values of the numerator and denominator that you are feeding into the VI.  Because they are arrays, use the array palette to manipulate them.  Please let me know if you have any issues with this.

[LucyXF]

Hi, thanks for your reply. I understand what you mean. Now I have this other question regarding the implementation of a controller. Is there any icons or vis that I can use for controller implementation with, for example, a certain transfer function expression? I tried the ones in Control Design module and didn't succeed. The CD Construct Transfer Function vi returned 0 value. So I suppose this vi is only for simulation or design purposes? Do I have to go down to the shift register levels to implement a certain discrete-time transfer function system? Thanks!

-Lucy

[SMeserve]

Hi Lucy,

I'm sorry.  I don't really understand what you are asking.  Can you clarify?  What have you tried and what isn't working?  What are you trying to do?

[LucyXF]

I'm trying to implement a controller design. I have the transfer function expression for the controller. I was wondering if there's any subroutine vis provided by Labview that I can use directly for the controller implementation (ie, just putting in the coeffiencts in the transfer function as parameters of the subroutine vi).

[SMeserve]

Hi Lucy,

Have you taken a look in the NI Example Finder?  There is an example called CDEx Controller with Transfer Function under Toolkits and Modules»Control and Simulation»Control Design»Implementation»Templates.

[LucyXF]

Hi, I tried this structure and however, it didn't work. The output of H(z) is zero for some reason. I don't know what was wrong. Here's the vi.

[SMeserve]

HI Lucy,

This is a very large VI.  Can you parse the problem down to just the effected VIs?