Transnasal Teleoperation Via Haptic Force Reconstruction and Environment Stiffness-Guided Adaptive Impedance Control.

Transnasal puncture and endonasal interventions are performed in narrow passages, where fragile mucosa is vulnerable to accidental wall contact, particularly from transient force peaks. We propose a switching teleoperation and force-feedback framework for transnasal manipulation using a Sigma.7 master and a Franka Research 3 (FR3) slave equipped with forceps. The system runs in unilateral mode during free motion and switches to bilateral control upon contact, improving maneuverability while maintaining realistic contact feedback. On the slave side, contact force is inferred from FR3 joint-torque sensing and model-based dynamics. Environmental stiffness is estimated online via recursive least squares, quantized into stiffness levels, and used to drive adaptive impedance shaping on the slave to suppress force peaks. For haptic rendering, the master emulates the slave impedance and reconstructs contact force from contact-induced slave The proposed method is evaluated through three distinct laboratory-based experiments to explore its potential for safer operation in constrained environments. In Experiment I, the method achieves 90% identification accuracy on materials with tissue-like materials. In experiments II and III, the proposed method achieved lower peak contact forces (about 5 N), lower cumulative strong interaction metrics (below 10 when threshold is 3 N), and higher success rates (88.3%) in narrow channel passage tasks compared to the three baseline methods.