Preliminary design of multi-axial contact force sensor for minimally invasive robotic surgery grasper

This paper presents a preliminary design and experimental results of a multi-axial contact force sensor for robotic surgery graspers. The sensor is a thin-film type capacitive one with a multiple cell structure capable of measuring normal and shear forces at contacts simultaneously. The structure of the sensor is determined via numerical optimization for maximizing sensitivity and based on the results, a prototype is fabricated by employing the silk-screening method. The characteristics of the sensor are evaluated with a multi-axial sensor calibration set-up and the sensitivities for two directional shear forces and a normal forces are measured to be 10.1, 10.3 and 6.1%, respectively. In this study, the feasibility of the sensor is confirmed as the proof-of-concept. In our future studies, a miniaturized pair of the proposed sensor will be embedded to a surgery grasper for in vitro validation.