SimScape Pneumatics 3 way Connector Query

Hi All,

I am building a Simscape model to create a digital twin of an experiment. It is a dual-acting pnuematic cylinder attached to a electrical load. The chambers are controlled by four 2-way normally closed VUVS valves (24v 1000L/min).

For initial model build and to aid debugging I am using four 2-Way Directional Valves (G), using a simple 0-1 signal to operate, which are normally closed, which then open the pnuematic circuit when the spool moves (inlet or exhaust).

The experiment has a simple 3 way G 1/4 connector that allows 2 VUVS valves to be pnuematically connected per chamber (inlet flow & exhaust flow, circled in yellow), as shown below in the a screenshot of the model.

When I simply connect ports A from both the inlet and exhaust Directional Valves (say chamber A) to feed a side of the dual-acting chamber the simulation will not run. To help debugging, if I just connect 1 Directional Valve per chamber and just operate the chamber in one direction, I have no issues and it runs, albeit just in one direction

How can I pnematiucally connect this layout as per experiment, to permit flow in both directions, from pressure supply (inlet) to atmosphere (exhaust) to each side of the dual-acting chamber?

Any help would be great

Thanks in advance

Patrick

[Steve Miller]

Are you able to attach the model to this post?

--Steve

[PB75]

HI Steve,

Thanks for your reply.

Can I forward it to you in an email?

Thanks

Patrick

[Leo Ng]

Hi Patrick,

It may be hard to give specific advice without seeing the error message and the model that generated it. However, one suggestion is to try to connect a pipe block between the 3-way connection and the actuator chamber. If you plan to model the 3-way conneciton with a 3-way directional valve block, it may also be helpful to insert a pipe between the 2-way valves and the 3-way valve. The pipe blocks adds some fluid volume (i.e., compliance) to break up the purely algebraic valve equations, which may be numerically beneficial to solving the system of equations.

Leo

[PB75]

Hi Leo,

Many thanks for your reply.

I originally had a single pipe block from the valve connection point to the actuator, to show heat loss in the feed pipes from valves to the dual-acting actuator, which would not solve. As you suggested I added a pipe block from each 2-way diectional valve before they join, and it runs. Have added a screen grab below (added pipe volume circled in red) to help others if they run into this issue.

Thanks again.

Patrick