MATLAB: Pulling against Gravity with a Pulley System

Question

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

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