Motion and force transmission of a flexible instrument inside a curved endoscope

Flexible instruments are increasingly used to perform advanced and complex surgical procedures either manually or robotically. The success of flexible instruments in surgery requires high motion and force fidelity, and controllability of the tip. However, the friction and the limited stiffness of such instruments limit their motion and force transmission. The implementation of flexible instruments in surgery necessitates their characterization, the development of proper tools to understand the effect of various mechanical parameters on their overall performance, and an improvement in motion and force fidelity. Therefore, this thesis describes 2-D and 3-D flexible multibody models of a flexible surgical instrument inside a curved endoscope, and covers the design and evaluation of a dedicated experimental set-up. The thesis also includes the evaluation of the models with the analytical and experimental results, and describes the strategy to improve force transmission along the axial direction due to the combined motion input at the proximal end of the instrument.