Requirements for artificial muscles to design robotic fingers

A. Rubiano, N. Jouandeau, L. Gallimard and O. Polit Abstract This work is part of the ProMain project that concerns the modeling and the design of a soft robotic hand prosthesis, actuated by artificial muscles and con-trolled with surface Electromyography (EMG) signals. In a first stage, we designed a robotic finger based on the equivalent mechanical model of the human finger. The model takes into account three phalangeal joints, flexion and extension movements are studied. The robotic finger has three Degrees of Freedom (DoF). The finger is designed to be under-actuated and driven by tendons, i.e. only one servo motor actu-ates the whole finger, and the motor is coupled to the finger mechanism through two flexible wires. As the aim is to design a robotic hand prosthesis that uses artificial muscles, we propose and carry out two experiments to characterize the specifica-tions of the actuator. The first experiment measures the pinch force of the human finger, and the second measures the achieved force using our robotic finger and five different servo motors. It allows us to enhance experimental results with the mathe-matical model of the finger, to identify the requirements of the artificial muscle.