Design and Kinematic Modeling of a Concentric Torsionally-Steerable Flexible Surgical Robot

Flexible robots with torsional motion can be used in transnasal surgery which can improve the flexibility of the end-effector during the operation. However, the torsion or twisting function still can not satisfy the requirement of the complex cavities with a different structure. This paper proposed a concentric torsionally-steer able (CTS) flexible surgical robot with novel concentric tendon-driven tubes. A 2L-RPRPR model based on the rigidized equivalence model is established to guide the spatial motion of the CTS robot. On the basis of this model, the cooperative motion between the inner and outer tubes can be realized, such as linear movement and rotation. In the meanwhile, the concentric tendon-driven tubes can perform different bending directions and curvatures according to various cavities. And the C-shape or S-shape with different curvatures required by the surgery operation can also be achieved. The results of the simulation and experiments show that the proposed CTS robot has larger workspace and higher operational flexibility, which are sufficient for surgical operation.