A Novel Miniature Spring-Based Continuum Manipulator for Minimally Invasive Surgery: Design and Evaluation

Minimally invasive surgery is gaining wide- spread attention in the laboratory and the clinic due to its advantages of less trauma, less pain, and faster recovery. Miniature continuum instruments with a large central channel are needed for reducing damage to healthy tissue and delivering multiple surgical tools in microsurgery such as fetal surgery and maxillary sinus surgery. In this article, we proposed a novel miniature spring-based cable-driven continuum manipulator characterized by its offset neutral bending plane and its simple and clever structure. These features enable the manipulator to have several advantages such as easy miniaturization, bending stability and uniformity, a large central channel, smaller cable tension required, and low cost. A piecewise constant curvature model, with the offset neutral bending plane taken into account, is presented for the kinematic control of the proposed manipulator. To explore the relationship between the cable tension and manipulator bending angle, the statics model based on the equivalent model principle, is exhaustively discussed. The accuracy of kinematics and statics models, as well as the design superiority, was verified experimentally. Furthermore, teleoperation experiments of peg-transfer tasks and porcine tissue laser ablation are conducted to verify the feasibility and effectiveness of the proposed manipulator in different forms. Final, design variations are showcased to enrich manipulator design and functionality.