Design of an anthropomorphic robotic finger system with biomimetic artificial joints

Abstract

We describe a new robotic finger that is composed of three biomimetic joints whose biomechanics and dynamic properties are close to their human counterparts. By using five pneumatic cylinders, the robotic finger is actuated through a series of simplified antagonistic tendons whose insertion points and moment arms at each finger joint are determined by the anatomy of the human hand. Air dynamic model is empirically solved for controlling the pneumatic system. In order to optimize our future controller for the robotic finger, we use Multi-Joint dynamics with Contact(MuJoCo) - a physics engine custom-developed - to construct a kinematic model for simulating the interaction between the fingers joints and tendons. Experimental data of the tendon excursions are used to validate the efficacy of the robotic finger model. Good fits are observed both in the DIP and PIP flexors (R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.93 and R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.83) and central extensor (R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.96).