How to model gas charged hydraulic accumulator for purpose of creating a custom accumulator

I am trying to replicate the gas charged hydraulic accumulator using basic elements in Simscape and SimHydraulics for R2014a student. So far I am unable to produce the same results as the accumulator element block.

The goal is to be able to make a custom accumulator as well as ensure that I control the gas properties.

I noticed that there is a diagram in R2014b help documents which is where I started: http://www.mathworks.com/help/physmod/hydro/ref/gaschargedaccumulator.html

The model shown in the link above is different than what is in R2014a. As a sanity check I should be able to produce the same results as my element model when compared to the gas accumulator block. I have been unable to do this robustly so far.

My question is (regarding the model in the link above): How do I properly specify the gas pre-charge for the piston chamber?

• I tried to specify the pressure by modifying the initial variables in the pneumatic piston chamber dialog. But I am not sure if the gas is escaping through the orifice block/port A of the pneumatic cylinder. I thought port A was just supposed to specify pressure acting on the piston.
• Also I would like to be able to control the gas properties. For now I plan on attaching gas properties to the line coming out of the piston chamber A port.

I will follow up with an attachment of my working model later today.

Answer 1

[Eetu Mäkiö]

Any help with this topic? I used the same picture for reference in my own work and ended up with similiar problems as Anvit here.

Answer 2

[Anvit]

Let me dig up my old work and see what I ended up doing. I do recall being able to achieve my goal in the end.

I will try and post something this weekend.

Answer 3

[Benjamin Talon]

Is someone in the Matlab community can answer us about the parameters' values to enter on the model above in order to obtain the same results with the block gas charged accumulator, please?