Model of cyclotorsion in a tendon driven eyeball: Theoretical model and qualitative evaluation on a robotic platform

In this paper we describe the mathematical model of a tendon driven eye. We focus on describing its movements, posing a specific attention on cyclotorsion, that is the rotation around the eye optical axis. This study aims at understanding the cause of a cyclotorsion effect that has been noticed on a real setup. The paper starts from a qualitative analysis of the effect. Then, it proposes two different models for its motion. Finally both models are validated by comparing their predictions with the outcomes on the real robot. Given the complexity of the system and of its motion results are for the moment just qualitative and quantitative comparison will be the goal of our future works.