A Multi-Contact-Aided Continuum Manipulator with Anisotropic Shapes

Cable-driven continuum manipulators have shown excellent benefits to work for endoluminal intervention. Demand of small diameter for confined anatomy limits the usage of multiple actuations, leading to limited DOFs and bending shapes. To address this problem, this letter proposes a multi-contact-aided continuum manipulator with anisotropic bending shapes. First, contact-aided compliant mechanisms (CCMs) are configured at different locations to introduce the specific constraints to enable the anisotropy. Then, the forward and inverse kinematic models considering contact blocks are built. The reachable workspace of the continuum manipulator is given, and simulation cases are studied to demonstrate the superiority of the proposed manipulator. Finally, a 3D-printed physical prototype is fabricated, and preliminary experiments are conducted to evaluate the model accuracy. Results show an average shape error of 1.98 mm (4.2%) and a maximum of 3.58 mm (7.6%). A robotic bronchoscopy platform integrated with the continuum manipulator is developed to conduct the airway phantom experiments. The shape deviation of the proposed manipulator from the centerline of the bronchus is 31.8% smaller than that of the constant curvature manipulator. The experiments validate the system-level feasibility and effectiveness of the developed continuum manipulator.