Analysis of strain transfer to FBG's for sensorized telerobotic end-effector applications

Sensorized instruments which cater for the measurement of interaction forces during surgical procedures are not available on current commercial Minimally Invasive Robotic Surgical (MIRS) systems. This paper investigates the effectiveness of advanced optical sensing technology (Fiber Bragg Grating) as surgical end effector strain/force sensors. The effects of adhesive bonding layer thickness and length are specifically addressed owing to their importance for effective strain transfer and ensuring compactness of the resulting sensing arrangement. The strain transfer characteristics of the compound sensing arrangement are evaluated by the examination of shear transfer through the fiber coating and adhesive layers. Detailed analysis of the sensing scheme is facilitated through the use of FEA. Validation of the resulting models is achieved through experimentation carried out on an application-specific evaluation platform. Results show that strain values from an FBG are comparable to that of an electrical strain gauge sensor.