A Micro‐3‐Degree‐of‐Freedom Force Sensor for Intraocular Dexterous Surgical Robots

Abstract

The continuum manipulator improves the intraocular robot flexibility during retinal surgery. Herein, a micro‐3‐degree of freedom (DOF) force sensor with a length of only 3.8 mm that can adjust the puncture angle during retinal vein cannulation (RVC) is proposed. Taking advantage of 3D printing technology, the optical fiber and injection line are embedded in the nitinol tube with flexible hinges to achieve integration of the force sensing and injection functions. A new fiber Bragg grating (FBG) configuration method and linear decoupling algorithm are also proposed herein. Static calibration experiments demonstrate excellent resolution of the force sensor, of less than 0.072 mN for transverse force and 0.738 mN for the axial force in the range from −20 to 20 mN. The proposed sensor is installed on a newly developed actuator, and an ex vivo experiment is performed on pig cadaver eyes. The interaction forces at each stage of the RVC are recorded in detail for the first time, further confirming the feasibility and effectiveness of the developed sensor for monitoring the RVC interaction forces.

Keywords

• continuum manipulators
• retinal surgery
• retinal vein occlusions
• three degree of freedom force sensors