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

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

Answer 1

[Sebastian Castro]

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

Answer 2

[Hamed Shamsi khani]

Hi.

A physical signal constant (PS Constant block) : B1

An Ideal Force Source (Ideal Force Source block): B2

connect 1 to S port of B2.

connect C port of B2 to ground.

connect R port of B2 to rod of cylinder.