Design of a Novel Concentric Double Continuum Manipulator With Novel Generatrix-Based Bending Motion Mode for Minimally Invasive Surgery in Narrow Spaces

Abstract The minimally invasive surgery (MIS) has developed rapidly in recent years, and many robotic surgical instruments have been designed. To realize a more precise operation, a more flexible manipulator is required to enable surgeons to perform complicated and precise procedures in narrow spaces. This paper presents a novel concentric double continuum manipulator (CDCM) for precise operations in narrow spaces, which takes up less space during bending due to its novel generatrix-based bending (GBB) motion mode. Due to the telescopic degree-of-freedom (DOF) of the surgical instrument's joints, the instrument can achieve coordinated variations in both scale and stiffness. The prototype of the CDCM device for MIS was developed, and the experiments were carried out. Both segments of the manipulator had two DOFs that can bend ±90 deg, and one telescopic DOF. The feasibility of the GBB mode was verified. The maximum payload with which the CDCM can maintain the deformation within 4 mm was obtained. The CDCM has high dexterity and payload capability, allowing more precise manipulations in narrow spaces.