Tip Force Estimation of a Hybrid Manipulator for Lower GI Interventions

Haptic feedback for robotic surgery requires force in- formation from the patient-side manipulator with high fidelity 1. Conventional force sensors for tip force measurement in compact, tendon-driven surgical manip- ulators face challenges in miniaturization, sterilization, and cost-effectiveness. Sensor-less tip force estimation from surgical images and intrinsic joint-level informa- tion is feasible but faces difficulties in generalization due to transmission loss caused by friction in actuation lines. This is especially true for flexible manipulators for endoscopic surgeries, where unpredictable shape- dependent friction losses occur due to the unknown sheath shape through the torturous natural orifices. This work presents a tip force estimation method for a novel hybrid manipulator designed for lower gastrointestinal (GI) interventions. The proposed system, integrating a soft robot with a tendon-driven continuum effector, al- lows for accurate tip contact force estimation unaffected by the long flexible sheath. Additionally, it eliminates the need for a sensor at the tip of the manipulator.