Simscape Cable System with Non-Rotating Pulley

Dear all,

I am working on the development of a multi-body model of a robotic finger on Simscape.

The finger is actuated through a cable system and the path the cable follows is bounded by different non-rotating pulleys. The figure below shows a sketch of the actuating principle.

I wasn't able to find a way on Simscape to model a non-rotating pulley and thus, for now, I am using the standard pulley available in the library. However this represents an ideal solution, while in our application the cable slide over the pulley and I would like to keep into account the friction between the non-rotating pulley and the cable.

Do you know any way to solve this issue?

Thanks in advance,

Kind regards,

Federico

[Kanat Suleimenov]

Hi @Federico Tessari, I am also working on the modelling of cable-driven mechanism for a finger in Matlab/Simscape. Could you please suggest any solution for a question: how to make the cable such that it goes through the hole located in the finger tip as shown in the figure attached?

Best regards, Kanat.

Answer 1

[Steve Miller]

Hi Federico,

The Pulley block does not permit slip between the cable and the pulley. You can approximate the friction of the cable by adding friction to the joint of the pulley. A custom friction model (measure pulley rotational speed and other quantities, calculate resistance torque) may get you quite close to the friction of a cable sliding over a non-rotating pulley.

--Steve

[Federico Tessari]

Hi Steve,

Thanks for the support!

At the end we implemented the solution using a custom friction model and it worked well.

Thanks again,

Federico