Reply To: Analysis of Robotic Finger

[peteroznewman]

I don't recommend you use Link/Truss elements because they are much more difficult to achieve convergence, but if you want to try, you should start with the simplest model possible, one link, one revolute, one string, and one spring.  You will need to take special care to create tension in the string as I did in the example I provided.

I recommend you replace the string with several spring elements. At the points where the string wraps around a corner, a dummy body will be used to represent that corner. The spring on each side of the corner is attached to the dummy body which will have a revolute joint to the center of the corner radius. The revolute joint can measure the normal force and provide a coefficient of friction at the appropriate radius. This will converge much more easily than the string modelled as Link elements making frictional contact with the corner.