A highly intuitive and ergonomic redundant joint master device for four-degrees of freedom flexible endoscopic surgery robot

Design and experiment of a 3-DoF master device with a 2-DoF parallel mechanism for flexible ureteroscopy

BACKGROUND

Traditional commercial master devices and specialied serial master devices meet insufficient workspace, low intuitiveness, low stiffness, and poor accuracy during master-slave mapping for robot-assisted flexible ureteroscopy (FURS).

METHODS

This paper presents a 3-DoF master device for FURS. A 2-DoF parallel mechanism was designed and utilised in the master device for higher stiffness based on requirements analysis. A Back Propagation Neural Network was built for the forward kinematics of the parallel mechanism during master-slave mapping. Analysis of mechanical characteristics was carried out for the usability of the master device. A contrast experiment on the phantom was conducted to evaluate the performance between the proposed master device and a previous one.

RESULTS

The completion time for each trial of the proposed master devices is shorter than that of the previous master serial device. Meanwhile, the proposed device provides a more comfortable operating style than the previous one.

CONCLUSIONS

The proposed 3-DoF configuration for the master device is with more intuitive performance. A better comfort level indicates its usability in clinical applications.

Miniature Manipulator Design and Cartesian Control for Minimally Invasive Transluminal Endoscopic Surgery

This paper presents a miniature manipulator under Cartesian control for minimally invasive transluminal endoscopic surgery. The manipulator had four degrees of freedom (DoFs) and a diameter of only 3.5 mm. The compact size of the manipulator allowed it to pass through the instrument channel of the endoscope, and its high dexterity allowed it to perform most of the operations in endoscopic surgery such as marking, grasping, hanging, etc. The implicit function relationship in the kinematics of the continuum manipulator was analyzed. By introducing the regression analysis method, the analytical form of the inverse kinematics was obtained. The distribution of singularities in the manipulator workspace was analyzed with emphasis. The presence of singularities made Cartesian mapping control between the primary side and secondary side impossible. By introducing the smoothing method of the joint trajectory, the discontinuity of the joint velocity at the singularity was avoided and the primary-secondary mapping under Cartesian control was realized. The trajectory-tracking experiment proved that the smoothness of the joint trajectory could make the manipulator smoothly pass through the singularity. The fixed-point marking experiment proved that the Cartesian control could improve the intuition of operation and the efficiency of task completion. Comprehensive performance experiments showed that the manipulator had enough dexterity to execute complex operations.

Design of an Intuitive Master for Improving Teleoperation Task Performance Using the Functional Separation of Actuators: Movement and Gravity Compensation

Teleoperation, in which humans and robots work together to improve work performance, is growing explosively. However, the work performance of teleoperation is not yet excellent. Master–slave systems with different kinematics and workspaces need space-transformation control techniques. These techniques cause psychological fatigue to an operator with poor manipulation skills. In this study, we propose an intuitive master design that focuses on fatigue. Large workspaces reduce mental fatigue; however, they lead to physical fatigue problems. To solve this problem, we reflect the role of actuators in the design, through functional separation using movement and gravity compensation. This study proposes the design and prototype fabrication of an intuitive master K-handler to improve remote-work performance. The K-handler features six degrees of freedom (DoF), an anthropomorphic structure, and a lightweight nature. It has a reach long enough to cover the workspace of the human arm to reduce mental fatigue. In addition, gravity compensation, which can reduce the operator’s physical fatigue during operation, is possible in all workspace areas.