A large displacement model for superelastic material side-notched tube instruments

Abstract Side-notched tube structures made of superelastic material are increasingly being studied in surgical robotics as they can easily be integrated into instruments and offer the surgeon enhanced dexterity. Their simple design ability to achieve large bending angles small radii make them particularly suited for use constrained workspace surgery. Up now, however, no model has been able accurately predict behavior such types angles. This study, therefore, proposes a novel approach displacements side-notched tubes taking account superelasticity material, non-constant curvature structure, well friction induced by actuating wire. More specifically, an equivalent, strain dependent, linear elastic modulus is used instrument’s material. The deformation each separate section calculated successively capture NiTi backbone. capstan equation cable friction. was tested on four samples 2.3 mm diameter angle with root mean square error (RMSE) low 5 . 4 ? ( 3.1 % ) position notch RMSE 0.33 mm 2.5 across its entire range 0 180 ). demonstrated both tension relaxation