Pulling against Gravity with a Pulley System

I am getting startet to work with Simscape and I made a very Simplistic crane which purpose is only to pull up a mass with a cable system.

I managed to build the Cable system, but when i insert a input signal for the "Revolution Joint" the mass just drops. I tried changing the rotation of the joint an I am convinced that the problem is that the pulleys can not pull against the gravity. Is it a problem that i used the pulleys on cylinder ?

Answer 1

[Juan Sagarduy]

Hi Matthias

It is difficult to say what happens without the model. But i wonder if the rigid transform between the revolute joint and the spool can be the cause of the problem. If the sign or value of torque are adjusted, and you see no difference, it is likely it.

In one of our examples port R (spool) and port F (winch joint) are directly connected. https://se.mathworks.com/help/physmod/sm/ug/block-and-tackle-with-four-pulleys.html

Hope this helped out. BR Juan

[Matthias Hueber]

I tried out the model with the solution you provided, but my mass is still dropping down. when i change the Gravity to a positive value my mass goes up.

This is my model withe the Revolute Joint 1 shown at the cylinder in the back. I hope that helps to identify the problem.

Is there any possibility that the system does not provide enough force to pull up the mass?

[Matthias Hueber]

I got to a solution. Thank you very much.