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Flexible ureteroscopy (FURS) has been developed and has become a preferred routine procedure for both diagnosis and treatment of kidney stones and other renal diseases inside the urinary tract. The traditional manual FURS procedure is highly skill-demanding and easily brings about physical fatigue and burnout for surgeons. The improper operational ergonomics and fragile instruments also hinder its further development and patient safety enhancement. A robotic system is presented in this paper to assist the FURS procedure. The system with a master-slave configuration is designed based on the requirement analysis in manual operation. A joint-to-joint mapping strategy and several control strategies are built to realize intuitive and safe operations. Both phantom and animal experiments validate that the robot has significant advantages over manual operations, including the easy-to-use manner, reduced intraoperative time, and improved surgical ergonomics. The proposed robotic system can solve the major drawbacks of manual FURS. The test results demonstrate that the robot has great potential for clinical applications.

The master manipulator of flexible ureteroscopy (FURS) robot system plays an important role in the master-slave control and its operating comfort influences the efficiency and quality of the robot-assisted surgery. The evaluation mechanism of operating comfort is commonly implemented based on the human joint movements and ignores the joint torque, which significantly influences on the surgical procedure and outcomes. This paper proposes an evaluation model of upper limb operating comfort based on joint torque for FURS robot through the Lagrange equation and NASA joint torque model. The reliability of the proposed evaluation model has been verified by the rapid upper limb assessment (RULA) by software Delmia and the muscle fatigue experiments on ureteroscopy by both of robotic and traditional manual approaches. The results indicate that the comfort index based on joint torque can well reflect the operating comfort for the ureteroscopy surgeon. Using the same with the evaluation model, the muscle fatigue experiments also show that the improved efficiency and quality of the master manipulator for FURS, which can facilitate to improve the design and control of the FURS robot system.

The robot-assisted natural orifice transluminal surgery (NOTES) typically involves applying the lengthy and slender continuum instruments/manipulators to get access to the target lesion sites, and then performs complex operations. However, due to the strong-nonlinearity of continuum robotic manipulators and the confined and tortuous anatomical paths, it’s difficult to establish accurate inverse kinematics (IK) model to achieve precise motion control and real-time shape sensing for accurately modeling their shapes. To tackle such difficulties, a model-free method based on neural network have been proposed to solve the IK problem and reconstruct the shape of a continuum manipulator at the same time using the training results from the electromagnetic (EM) tracking approach. For the IK problem, the relationship between the tip position and the corresponding cable lengths can be learned and for the shape estimation problem, the mapping from the cable lengths to the shape of the continuum robot can be established. A dataset of 500 random continuum manipulator postures was used to train the neural network, with recorded EM sensors-tracked positions logged synchronously to the cable lengths. Experiment results show the proposed model-free method could achieve high accuracy and reliable inverse kinematics and shape reconstruction outcomes.

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 $300 \times 300 \times 173.2$ mm3. 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.