MATLAB: How to add gravitational acceleration acting on a mass that is connected to a cylinder in Simscape

SimscapeSimscape Fluidssimulink

I have a double-acting cylinder connected to a mass at its mechanical port R, and I am adding pressure at end A of the cylinder to extend the piston and hence drop the mass. I want to add a gravitational acceleration acting on the mass as well. I tried to use the ideal force source (to implement F=mg), but it does not seem to work. I have uploaded a screenshot to show what I did. Could you please help me?
Thanks a lot. Asmaa

Best Answer

Your force source approach is the right way to model a weight. Two things I would check:
  1. You should also attach a "Mass" block to the R port of the cylinder. You can use (50/9.81) kg for the mass, I guess.
  2. Check the upper and lower limits/initial displacement/directionality of the cylinder block. Chances are your lower displacement limit is 0 and that small negative displacement is due to the large stiffness of the hard stop representing that contact.
- Sebastian
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