simscape pneumatics

Hi, I'm trying to create some simple air plow system with pneumatics: pressure source-pipe1-pipe2-constant volume chamber. (two pipes ith different pressure losses, e.g. air filter and dryer). But it seems that Pneumatic are highly unstable: if I use just one pipe - everything works fine, but if I use two pipes (air filter and dryer) simulink crashes and produce crasy errors: one of them is like "chamber volume non-finite". Another strange thing - I built more complicated model: pressure source generates compressed air flow, air flows through two dryers, and then through three air filters. At first it didn't work. But after two rebuildings from scratch it work just fine, but (!!!!) after several simulations it crashed and never worked again. Is it because pneumatics is new in simscape or what?

Answer 1

[Guy Rouleau]

I would like to mention 2 things:

1 - Connecting pneumatic components requires a good knowledge of the domain and the equations involved. Make sure you respect the connection constraints described here:

http://www.mathworks.com/help/toolbox/physmod/simscape/ug/br7vtpp.html#br7vtvl-1

- If MATLAB crashes, please send reproduction steps and model to technical support.

[Tomas Iesmantas]

Hmm, as I understand, if I connect two pneumatic resistive tubes in series, both of tubes has to have volumes associated with them - say, constant volume pneumatic chamber. I did so and everything worked just fine. But I'm not sure about how big volume should be associated with tube? Is volume should be equal to volume calculated from tube parameters?

Answer 2

[Nikhil Chotai]

I am involving in same type of problem I think you have to divide volume like you are using two resistive tube one have 1/2 volume and second have 1/2 volume.

Answer 3

[Nikhil Chotai]

I am involving in same type of problem I think you have to divide volume like you are using two resistive tube one have 1/2 volume and second have 1/2 volume.