Why does the simulation results look so different?

[Haifei]

Hi, all,

I use both simulink and labview simulation to simulate a two link manipulator under the same mathematic model, the same initial condition, the same ODE sovler, the same input.  However, the results are quite different. Does anyone know the reason? the simulink and labview files are attached. Thank you very much!

Regards,
Haifei

[Nadim R]

Hi Haifei,

I tried looking at your TwoLinkModel.vi, however, I get some broken arrows- probably due to software differences.  Can you list the NI software and versions that you are using?

Regards,

Nadim
Applications Engineering
National Instruments

[Haifei]

Hi Nadim,

Thank you for your response. My LabVIEW version is 8.0. Simulation module is 2.0.0. Thank you again for your time.

Regards,
Haifei

[J.Harv]

Haifei--

     I took a look at your code and everything on the NI side seems to be fine.  Unfortunately, we have to reserve a test computer to run Matlab.  I will look into this to see if there is anything wrong with LabVIEW but I just wanted to let you know that it might take awhile.  I will try to be as quick as possible but cannot give any timeline at this point.  Thanks for letting us know about this and thank you for your patience.

Regards

John H
Applications Engineer
National Instruments
http://www.ni.com/support

[Haifei]

Hi, John,

Thank you for your help.

Regards,
Haifei

[Haifei]

Hi, All

I fixed the problem.Thank you for all the responses.

Regards,
Haifei

[J.Harv]

Haifei-

      Do you know what was happening, or what was causing the two to be different? If you have a second, try to post any information that you have!  It could help someone in the future if they are having the same issue and read this post.  Thanks so much.

     I'm very glad that everything is working, If you have any other questions, please, let us know.

Regards,

John H.

[Haifei]

Hi, John,

It's my fault.  I am sorry for my careless. behind the formula node, there are two block, I thought I deleted them. The lesson is that when something strange happened, try to move big block to see is there any small block behind it.

Regards,
Haifei

[Darren]

Hi Haifei,

Did you know that the VI Analyzer would have detected this problem?  Specifically, it would have flagged the wires going under the Formula Node to the hidden objects beneath.  I always recommend that LabVIEW users run the VI Analyzer on their code *first* before they spend a bunch of time debugging only the diagram objects they can see... 🙂

The VI Analyzer is available for purchase as an add-on toolkit...it is also included in the Developer Suite.

-D