Dynamic modeling and system identification of internally actuated, small-sized continuum robots

Abstract

Small-sized continuum robots (CRs) have shown promising applications in multiple fields, including minimally invasive surgeries. This paper contributes to the field by presenting dynamic modeling and system identification of internally actuated, small-sized CRs in which continuous interactions between the internal actuation mechanisms and the flexible backbones are considered. First, a dynamic model of a flexible backbone sheath is developed. Next, an equivalent discrete model is identified to simulate the dynamics of CRs with continuous interactions. Moreover, based on the existing friction models of passive tendon-sheath mechanisms, the friction model within the proposed discrete model is modified to better resemble the continuity of the interaction. A prismatic ablation catheter is then used as the benchmark for the experimental study, in which parameters for the handle, shaft, and the proposed discrete model for its bending section are considered unknown. The identified model estimates the catheter motion with a maximum error of 4.5 mm at the tip position, which represents 5.6% of the length of the bending section of our experimental catheter.