Fiber-Bragg-grating based Force Sensor with Dual Structure for Minimally Invasive Surgery

Abstract

In robot-assisted minimally invasive surgery, force sensing is critical for the dexterous and accurate manipulation of surgical instruments. Herein, we present a 3-DOF force sensor based on fiber Bragg grating (FBG) with a hollow channel to accommodate existing surgical instruments. The proposed force sensor is designed to balance the performances of transverse and axials forces in terms of sensing range and resolution. A dual-structured design allows the force balance by increasing transverse stiffness and decreasing axial stiffness. From finite element analysis, the dual structure increases the range of transverse force 4.3 times compared to a single structure. The ratio of transverse force to axial force is also improved by the dual structure-l.l, whereas it is 3.2 for the single structure. Calibration results show resolutions of 6.5 and 5.8 mN for the transverse forces along the x- and y-axes and 22.2 mN for the axial force within 0–1 N, respectively.