Concentric Wire-Driven Robots With In Situ Torsion for Transnasal Surgery

Minimally invasive surgery within confined cavity, such as maxillary sinus surgery, commonly requires the flexible robots with more degrees of freedom, a greater operating space as well as higher motion dexterity. To meet the aforementioned requirements, this article proposes a concentric wire-driven robot that combines the merits of adjustable operating length of the concentric-tube robots and the larger bending angle of the wire-driven robots. It is characterized by a bidirectional in situ torsion without variation of the overall nonplanar shape. The forward and inverse kinematic models are established to address the coupled bending and torsion. The workspace analysis shows that the proposed robot provides a volumetric reachable workspace, which is much larger than traditional 2-segment wire-driven robots. The dexterity analysis shows the outstanding dexterity when compared with robots of various configurations. The in situ torsional motion was demonstrated by the novel robotic arm and the phantom experiments to validate the feasibility of the proposed robot for maxillary sinus surgery. Finally, the experiments on motion accuracy verify the operational performance of the robot.