A Novel Master Manipulator with Force Feedback for Robot-Assisted Natural Orifice Transluminal Endoscopic Surgery

The robot-assisted Natural Orifice Transluminal Endoscopic Surgery (NOTES) enables to perform complex and delicate operations along anatomical tortuous paths through natural orifices. Such emerging techniques also pose difficulties for the master manipulator design. Based on the requirement analysis and ergonomics for robotic NOTES systems that rely on a master-slave configuration, this work proposes a new type of master manipulator in a combined parallel and serial configuration, providing advantages in terms of improved stiffness and accuracy, large workspace, low damping ratio, easy implementation of force feedback. It has three degrees of freedom (DoFs) with one driving unit for each DoF, including translation and two rotation forms, and supports both passive mode and active mode, permitting force feedback in all the three DoFs. A simplified and improved parallel mechanism with a planar six-linkage configuration is proposed to achieve translational motion, and it adopts a rotational form to replace the traditional approach using a linear guide rail. The singularity of the mechanism is analyzed, and the design has been improved to avoid reaching singular positions. The master arm platform has been fabricated and assembled, and it possesses a large workspace of 300x300x173.2mm(3). Both simulation and experiments have been performed to validate its effectiveness and advantages, and the proposed design can be applied as a generalized master platform to target NOTES surgery.