Due to the large number and complex structure of bronchial branches, frequent orientation and insertions during bronchoscopy are likely to cause surgeon fatigue and errors. Therefore, we designed a robotic-assisted automatic intervention system (RAIS) based on image guidance, which aims to realize automatic orientation and insertion of bronchoscope, for improving the intelligence and efficiency of the bronchoscopy. To realize image guidance, we proposed a highly robust and accurate lumen center detection method, which combines deep learning-based object detection and histogram back-projection. With image guidance of lumen center, RAIS automatically completes the orientation and insertion of bronchoscope. The results of human phantom lung experiments show that the accuracy and recall of proposed lumen center method can respectively reach 94.12% and 86.23% when the bronchoscope is being localized by RAIS. Moreover, the results show that it is feasible to automate the orientation and insertion of bronchoscope using RAIS, which is more efficient than the manual operating the robot. The proposed RAIS could replace the surgeon in performing a large number of repetitive and simple tasks, which can efficiently reduce the workload of the surgeon and improve the safety and efficiency of the procedure.

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.

This paper presents a Fiber Bragg Grating (FBG)-based torque sensor with high sensitivity and miniature size for MIS instruments and multi-finger hands. The proposed sensor design mainly consists of a torque-sensitive flexure structure and two diagonally arranged optical fibers embedded with FBG sensing elements. An improved hollow hexaform structure with flexible hinges has been utilized to design the torque-sensitive flexure with an excellent linear measurement range and a solid capacity to resist non-torsion loading. Two optical fibers with an FBG inscribed each adopt a two-point gluing configuration with a tightly stretched status, and they are arranged diagonally along the hyperboloid surface. This configuration can obtain improved sensitivity and resolution and avoid the drawbacks of FBG chirping and low repeatability. Finite element modeling (FEM)-enabled simulation has been implemented to perform design optimization for further sensor sensitivity improvement and performance investigation. The prototyped sensor has been calibrated and achieves a high resolution of 0.062N ·mm within [-100, 100N ·mm] and excellent linearity with a small linearity error of 0.68%. The crosstalk experiments on the bending moment of Mx and My and the axial force have been conducted to validate the anti-interference capacity on the basis of the small values of 0.47%, 0.31%, and 1.78%. The proposed design also supports convenient customization to achieve the adjustable measuring range and torque sensitivity, which has been validated by another sensor version with a resolution of 0.26 N·mm within [-500, 500N ·mm].

Robot-assisted minimally invasive surgery (MIS) has shown tremendous advances over the traditional technique. A crucial challenge for developing a MIS robot is the kinematic design of the remote center-of-motion (RCM) mechanism. In this paper, a class of spatial RCM mechanism is analyzed. They are obtained by generating virtual parallelograms. The main process is to construct a line that passes through a fixed point under the mechanical constraint. The axis of the surgical tool is then constrained to parallel with that line. Hence, due to the geometrical feature of the parallel lines, the axis of the surgical tool will always pass through a fixed point, i.e., the RCM point. Due to the specially designed structure, the fixed point does not need to be physically belonging to the mechanism. The geometrical analysis method is employed to obtain the closed-form solution of the forward kinematics of the proposed mechanisms. Due to the high load capacity of parallel mechanism, the robots based on the proposed RCM mechanisms have promising applications as an external positioner to be used in robotic single-port surgeries.

The flexible ureteroscope suffers from complex inherent motion hysteresis behaviors due to the lengthy and slender configuration with a typical diameter of less than 3mm, the manual cable-driven approach via tendon-sheath mechanism for force and motion transmission and the associated nonlinear dead zone caused by tendon slackening at around the zero position. The highly constrained intraluminal environment and the lack of sensor integration have further limited the feedback acquisition for closed-loop control. Therefore, the hysteresis compensation for the ureteroscopes has become more essential but remains challenging. To address the associated hand-eye incoordination, limited control accuracy, and increased surgical risks, this work presents an analytical modeling and feedforward compensation method for the ureteroscope based on a modified generalized Prandtl-Ishlinskii (MGPI) model. The designed model cascades a piecewise-linear-envelope-function-based symmetric generalized PI model (SGPI) and a two-sided dead zone model (DZ) to characterize the backlash, asymmetric hysteresis, and nonlinear dead zones. The feedforward compensator has been analytically derived and integrated into a motorized ureteroscope platform. Experimental results indicated that the proposed model has successfully captured the complex hysteresis with a modeling error of only 1.44% within a wide motion range of 440∘. The tracking experiments of periodic and non-periodic signals have been performed. The results indicated that the proposed compensator has significantly suppressed the hysteresis by 60% 70% under different circumstances. Comparison simulations and experiments with other compensators have also demonstrated its advantages.

With the development of minimally invasive surgery (MIS) technology, higher requirements are put forward for the performance of remote center of motion (RCM) manipulator. This paper presents the conceptual design of a novel two-degrees-of-freedom (2-DOF) spherical RCM mechanism, whose axes of all revote joints share the same RCM. Compared with the existing design, the proposed mechanism indicates a compact design and high structure stability, and the same scissor-like linkage makes it easy to realize modular design. It also has the advantages of singularity-free and motion decoupling in its workspace, which simplifies the implementation and control of the manipulator. In addition, compared with the traditional spherical scissor linkage mechanism, the proposed mechanism adds a rotation constraint on the output shaft to provide better operating performance. In this paper, the kinematics and singularities of different cases are deduced and compared, and the kinematic model of the best case is established. According to the workspace and constraints in MIS, the optimal structural parameters of the mechanism are determined by dimensional synthesis with the goal of optimal global operation performance. Furthermore, a prototype is assembled to verify the performance of the proposed mechanism. The experimental results show that the two-degrees-of-freedom prototype can provide a reliable RCM point. The compact design makes the manipulator have potential application prospects in MIS.