Articulated mechanism design and kinematics for natural orifice translumenal endoscopic surgery robot

Natural orifice translumenal endoscopic surgery (NOTES) has reduced the invasiveness of surgery by eliminating external incisions on the patient. With this type of procedure, recovery time is drastically shortened, cosmetics are improved, and infections and pain are greatly reduced. For NOTES procedures to be successfully performed, a flexible endoscope or similar instrument is important for passing orifice flexures. However, technological deficiencies like poor angulations of surgical instruments introduced through working channels in flexible endoscopes, the lack of scope fixation, and lack of scope stiffening are technological barriers which prevent NOTES from being widely accepted in human surgeries. A novel multifunctional robot with an articulated drive mechanism for NOTES has been developed. The steerable articulating drive mechanism is connected to the robotic end effector to guide the robot and navigate through a natural orifice. The design process for the articulating drive mechanism and engineering analysis are discussed in this paper. Workspace of the drive mechanism with and without a translational insertion degree of freedom is presented in detail. The kinematics of the drive mechanism is also discussed. Additionally, friction in the spherical joints of the drive mechanism is explored to characterize its influence on the overall shape achieved by the articulation, including the effects of varying the total length in the steering mechanism. The surgeon control console for the drive mechanism is briefly discussed as well. Bench-top testing results are presented as proof of feasibility of the design.