Analysis on the force propagation of the tendon-sheath actuation in dexterous surgical robots

Abstract

Tendon sheath actuation is widely used in the minimally invasive surgery (MIS) robotic system, particularly in the single port laparoscopy (SPL) and the natural orifice transluminal endoscopic surgery (NOTES) robots. The force propagation from the proximal end to distal end is the most important characters for the tendon sheath actuation, and the friction is a major problem. In this paper, a classical friction model is presented at first. A series of experiments are carried out to verify the correctness of model. Some factors like the pulling velocity, the tendon diameter and the sheath curvature, which are not considered in the model are also tested in the experiments. The results show that some of these factors also have effect on the friction. A modified friction model is presented to adjust the different tendon diameters.