A novel cascaded-FBG-based surgical forceps for simultaneous clamping force and position sensing in MIS

Reliable force sensing is essential for improving intraoperative safety and precision in minimally invasive surgery (MIS). However, existing forceps-integrated sensors may suffer from electromagnetic interference or position-dependent errors. Here, we develop a 5-mm sensorized surgical forceps integrating cascaded fiber Bragg gratings (FBGs) and dual elliptical flexure hinges for simultaneous clamping-force and position sensing. A force-position estimation method is proposed, where the absolute wavelength-shift ratio of FBG-1 and FBG-2 estimates the clamping position, while their wavelength-shift difference with position-dependent compensation enables force evaluation under concentrated and distributed loading. The forceps achieves average force sensitivities of 44.06 pm/N and 42.31 pm/N under concentrated and distributed loading, respectively, with maximum dynamic errors of 7.11% for force and 2.07% for position. Temperature calibration (25–50 °C) and coupled temperature-force experiments (30–40 °C) verify the effectiveness of the proposed compensation method in reducing temperature-induced errors. Phantom-based suturing and tissue-manipulation tasks further demonstrate the feasibility of simultaneous force-position sensing under surgical interactions.