Accurate force sensing is important for endoluminal intervention in terms of
both safety and lesion targeting. This paper develops an FBG-based force sensor
for robotic bronchoscopy by configuring three FBG sensors at the lateral side
of a conical substrate. It allows a large and eccentric inner lumen for the
interventional instrument, enabling a flexible imaging probe inside to perform
optical biopsy. The force sensor is embodied with a laser-profiled continuum
robot and thermo drift is fully compensated by three temperature sensors
integrated on the circumference surface of the sensor substrate. Different
decoupling approaches are investigated, and nonlinear decoupling is adopted
based on the cross-validation SVM and a Gaussian kernel function, achieving an
accuracy of 10.58 mN, 14.57 mN and 26.32 mN along X, Y and Z axis,
respectively. The tissue test is also investigated to further demonstrate the
feasibility of the developed triaxial force senso