Investigation and experimental measurement of scissor blade cutting forces using fiber Bragg grating sensors

• Published in: Smart materials and structures 2011-10, Vol.20 (10), p.105004-1-9
• Main Authors: Callaghan, D J, Rajan, G, McGrath, M M, Coyle, E, Semenova, Y, Farrell, G
• Format: Article
• Language: English
• Subjects: Applied sciences; Biological and medical sciences; Blades (cutting); Computer science; control theory; systems; Control theory. Systems; Cutting; Detection; Exact sciences and technology; Fibers; Fracture mechanics; Fracture mechanics (crack, fatigue, damage...); Friction; Fundamental areas of phenomenology (including applications); Mechanical contact (friction...); Medical sciences; Physics; Robotics; Sensors; Solid mechanics; Strain; Structural and continuum mechanics; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases
• ISSN: 0964-1726; 1361-665X
• DOI: 10.1088/0964-1726/20/10/105004

This paper reports on unique and scalable sensorized medical scissor blades for application in minimally invasive robotic surgery. The blades exploit the strain sensing capabilities of a single fiber Bragg grating (FBG) sensor bonded to the blade surface. This smart sensing structure allows detection of friction and material fracture forces during cutting and subsequently enables accurate estimation of the blade kinetic friction coefficient and fracture toughness values of the material being cut. We present theory on the determination of strain variation along the blade length during combined direct and lateral loading of the blade element during operation. Demonstration of the sensorized instrument is realized on an application specific experimental test-bed employing a commercial interrogation system for signal demodulation. Friction and cutting forces measured using the FBG are validated against load cell force data from the test-bed. Characterization tests showed that the sensorized blade has an unfiltered force sensing resolution of 0.5 N over a 30 N load range. This work demonstrates that a single optical fiber placed onto cutting instrument blades can, in an unobtrusive manner, reliably measure friction forces and material fracture properties during surgical cutting.