Performance evaluation of optically sensorized tendons for articulate surgical instruments

This study proposes an optically sensorized force-sensing tendon for minimally invasive surgical instruments. The tendon is composed of a high strength, polarization maintaining (PM) optical fiber with Bragg sensors (FBGs) that negate the cross-sensitivity of conventional FBGs. The PM-FBG fiber is locally reinforced with high stiffness Kevlar that enhances its load carrying capacity while enabling higher curvatures in tendon routing. The composite tendon has a mean diameter of _268 lm which preserves the form-factor of instruments within this scope. Importantly, the tendons can improve the functionality of such tools by enabling local force and tissue-resistance estimation. This paper explores the performance of these sensorized tendons in terms of strength, stability, response under dynamic load, friction, and sensitivity as a force measuring tool within an 18 Ga articulate Nitinol (NiTi) cannula (a proxy for potential applications). Results reaffirm the potential of a bi-modal sensing and actuation component within instruments for robotic surgery.