RESUMEN
Objective:To develop a skeleton structure for the flexible manipulator of a robotic system used in natural orifice transluminal endoscopic surgery (NOTES), meeting the performance requirements of surgical actuators.Methods:A flexible manipulator structure and a control strategy for the corresponding structure were designed based on metal braiding technology. Geometric relationship formulas were derived according to the mechanical structure characteristics of the flexible manipulator. A theoretical model was established using the chained beam-constraint-model (CBCM) and mechanical spring theory. The finite element model of the mechanical structure was established, and simulation analysis was performed to verify the accuracy of the theoretical model. The bending stiffness of the metal-braided structure was tested to verify the load capacity of the flexible manipulator.Results:A flexible manipulator structure and a control strategy for the corresponding structure were designed based on metal braiding technology. With proper constraints, the maximum strain of the metal ring as a single stressed unit was about 1.49% when subjected to an axial force of 0.5 N. At this time, the material was in the linear elastic phase and the maximum deformation was about 0.308 9 mm, which was 3.26% higher than the theoretical value. The maximum strain of the manipulator skeleton was about 0.21% in the linear elastic phase. The maximum total deformation was about 7.135 5 mm, which was 6.30% higher than the theoretical value. The flexural stiffness of the manipulator skeleton was calculated to be 3.19 N·mm 2, which was comparable to a flexible manipulator made of shape memory polymers (SMPs) of the same magnitude and size. Conclusions:A skeleton structure for application to NOTES robotic flexible manipulators is developed that meets the support stiffness requirements for performing NOTES surgical tasks.