nonlinear state space equations

[iman-d]

Hi!

I want to ask if anybody knows how to solve a nonlinear state space equation using labview

for example:

initial conditionx0 = [298; 305];

xdot(1)=(1/(Mg*cvout))*((mdot*cpin*Tg1)-(mdot*cpout*x(1))+U*A*(x(2)-x(1)));
xdot(2)=1/(mH*cpH)*(Q-U*A*(x(2)-x(1)));

output equ : y=x

And in equations above cpout is a nonlinear function of  x(1):
cpout=cp1*y(1)+cp2*y(2)+cp3*y(3)+cp4*y(4);

cp4=R*(3.28+.593e-3*x(1)+.04e5/x(1)^2);

so we can not calculate A,B,C and D matrix for this to use in labview.( we have nonlinear system)

How can i model and solve this state space equation in labview?

Thanks for your help

[TheNIDragon]

Howdy iman-d!

There is a VI under Mathematics >> Scripts & Formulas >> Zeros called "nd Nonlinear System Solver". This may be exactly what you are looking for. Give this VI a shot and let me know if this works!

[shami_jadoon]

i don't know the important of this solver VI. it gives for example x,y,z that is unkown to us,,, than from that how we can find the state space or transfer function of that equation...

[Barp]

The best way to solve this equation is to use the "LabVIEW Control Design and Simulation Module (CDSiM)". If you have it installed, you can see a very good example in:

C:\Program Files (x86)\National Instruments\LabVIEW 2016\examples\Control and Simulation\Case Studies\Nonlinear\Pendulum\SimEx Nonlinear and Linear Pendulum Simulation.vi

This example, shows three different ways to obtain the State-Space and the transfer function of a pendulum. The key way to do that is using the "SIM Linearizer" function.

Hopefully this gives you the right direction to solve this exercise.

[shami_jadoon]

wow ... i mean just wow...i really exactly want the same direction... just wana say you,,, love u bro,,,, 

can you please share this example as my labview version is 2014 and so i don't have this example.. i will be very thankful...

[Gregory]

Do you have the LabVIEW Control Design and Simulation Module installed that was referenced?

[shami_jadoon]

yes i have this module,,, there is also pendulum example but not so much in detail as you have shown,,i just need this example and also same like this if available in 2016 labview examples,,, please.

[jordans]

Hello shami_jadoon,

It looks like the example that Barp references is from the LabVIEW 2016 Control and Simulation examples. If you have the Module installed, you should be able to access the example by following his link.

C:\Program Files (x86)\National Instruments\LabVIEW 2016\examples\Control and Simulation\Case Studies\Nonlinear\Pendulum\SimEx Nonlinear and Linear Pendulum Simulation.vi

Best of luck on your project! 

[shami_jadoon]

labVIEW 2014 is installed in my computer and in that version this example is not available that's why i ask for that example...

[jordans]

That makes sense, however, I also have LabVIEW 2014 and the example is available with the toolkit installed. Examples have stayed fairly similar between LabVIEW versions since LabVIEW 2011. If you can't find it through example finder, I have also uploaded it here for your convenience.