Transurethral resection of bladder tumor (TURBT) is a common method in urology for the diagnosis and treatment of bladder cancer, especially in non-muscle invasive bladder cancer. However, the surgery using the resectoscope, which is one of rigid-type endoscopy with a resection loop, has some limitations and difficulties such as difficulty in approach to deep parts of the bladder, uncomfortable posture of the surgeon during surgery, inconsistency in result due to surgeon dependency, insufficient accuracy of resection, or lack of intuitiveness.

This study aims to develop the robotic system for TURBT. The system includes a steerable endoscopy mechanism, articulated robot arm with a wire driving unit, master manipulator, and master and slave robot bases including controllers. Based on the concept, the TURBT surgical procedure using the resectoscope is analyzed and 3-dimensional model of the system is implemented.

....

The study aimed to demonstrate the feasibility and acceptability of smartphone-based wide-field articulable endoscope system for minimally invasive clinical applications in resource-poor countries.

A thin articulable endoscope system that can be attached to and actively controlled by a smartphone was designed and constructed. The system consists of a flexible endoscopic probe with a continuum mechanism, four motor modules for articulation, a microprocessor for controlling the motor with a smartphone, and a homebuilt application for streaming, capturing, adjusting images and video, and controlling the motor module with a joystick-like user interface. The smartphone and motor module are connected via an integrated C-type On-The-Go (OTG) Universal Serial Bus (USB) hub.

We tested the device in several human-organ phantoms to evaluate the usability and utility of the smartphone-based articulating endoscope system. The resolution (960 × 720 pixels) of the device was found to be acceptable for medical diagnosis. The maximum bending angle of 110° was designed. The distance from the base of the articulating module to the tip of the endoscope was 45 mm. The angle of the virtual arc was 40.0°, for a curvature of 0.013. The finest articulation resolution was 8.9°. The articulating module succeeded in imaging all eight octants of a spherical target, as well as all four quadrants of the indices marked in human phantoms.

This study presents a new master manipulator applied to robotic systems for arrhythmia ablation. The manipulator is designed to implement the concept of two different master-slave teleoperation controls in the clinical application. One is the conventional control between the master and catheter-handle in the slave site and the other is catheter tip manipulation corresponding the master motion. For the purpose, the master has six degrees of freedom (DOF) and consists of three main components: a spherical mechanism for rotational motion of 2-DOF, 3-RRR planar parallel mechanism with 3-DOF, and counter-weight lifting mechanism for the vertical movement. Two mechanisms except the lifting mechanism are parallel chains and structurally more complicated. Therefore, their forward kinematics are analyzed, and workspaces are simulated. To evaluate the applicability for robotic catheter systems, the manipulator prototype was tested for its smoothness, workspace, and teleoperation performance. The subjects in the smoothness test reported no considerable friction and jerk in free movement in the three-dimensional space as shown in the recorded curves. The workspace test shows the actual workspace is similar to the simulated one except some structural constraints in the 3-RRR mechanism. For the last test, a robotic catheter teleoperation system with a slave robot and the software structure for the robotic catheter control system with electrical connection of each component were built. The result performed by five different users shows the motion of the slave robot well tracks that of the master device with small average errors and time delay that are acceptable in robotic catheter teleoperation systems.

Abstract

Rapid advances in robot technology have enabled the application of robotic systems beyond conventional manufacturing industries, including various applications in medical diagnosis and treatment. One of the latest research topics for medical robots is robot-assisted intervention. Intervention encompasses various procedures including biopsy, ablation, drug or device delivery through vascular access, and endoscope-based dissection. In such procedures, the robot can control a catheter inserted in a blood vessel, manipulate needle to adjust the pose and follow the planned path, or place stents inside a vessel. The advantages of the interventional procedures include minimal invasiveness, reduced pain, and faster recovery; these can be extended to improving clinical outcomes and patient benefits from the enhanced precision, dexterity and radiation safety with the application of a robotic control system. Radiation hazards to radiologists and patients from conventional computed tomography (CT)- or cone-beam CT-guided needle biopsies or ablation procedures are a clear disadvantage, but robotic needle manipulation using a master-slave teleoperation type robot system can provide significant benefits to both patients and clinicians. Most of the studies on robot-assisted needle manipulation systems have focused on adjusting the pose and insertion of the needle, which is the manipulation of a single needle. In a biopsy, a typical needle insertion intervention, two different kinds of needle assemblies (i.e., introducer and biopsy gun) are used in sequence, which differs from the ablation procedure where the insertion of the therapy needle mainly involves placing the tip at the target lesion. So far, the developed robotic needle insertion systems do not provide a fully automated sampling procedure, which includes the initial insertion of the introducer needle and multiple applications of the biopsy gun for tissue sampling. In this study, a new end-effector was developed for a teleoperation type needle intervention robot system with full biopsy procedure automation, and the concept was verified. The end-effector mechanism was designed to perform the series of tasks required for biopsy procedure, including needle pose adjustment, the insertion of two different types of needles, sampling the tissue specimen, and repeating the sampling.

A tensegrity-based compliant parallel mechanism is introduced in this paper. Tensegrity structures are basically comprised of compressive components, referred to as struts, and tensile components, referred to as ties. The struts and ties are typically stiff. When the tensegrity mechanism is assembled, the ties are placed in tension which pre-stresses the entire mechanism such that the ties are in tension and the struts are in compression.

This paper presents an analysis of a spatial tensegrity-based mechanism. In this study, a moving body in space is joined to ground by seven compliant leg connectors. Each leg connector is comprised of a spring in series with an adjustable length piston. Two problems are solved in this paper; one is reverse kinestatic and the other is stiffness synthesis problems. In the reverse kinestatic problem, the values of the seven spring constants and free lengths are given and the force magnitudes applied to the seven springs and the lengths of the seven pistons are determined such that: (1) the top body is positioned and oriented at a desired pose; (2) the top body is at equilibrium while a speci.fied external wrench is applied; and (3) the total potential energy stored in the seven springs equals some desired value. In the stiffness synthesis problem, the values for the seven spring free lengths are given and the values for the seven spring constants and the lengths of the seven pistons are determined such that conditions (1) and (2) from above are met and also the instantaneous stiffness matrix of the top body equals a specified set of matrix values. The paper formulates the solutions of these problems. Numerical examples are also presented.

This is the study of the dynamics and control design of a robotic finger with a compliant fingertip. The finger is modeled as an n-link serial chain whose last link is composed of both rigid and compliant parts. The compliant part (fingertip) is a rigid spring. The dynamics of the rigid spring is modeled as a spring mass system with the mass of the spring lumped at its center of mass and a desired compression of the spring during contact is achieved by referring the spring dynamics to the joint space thereby using the joint torques to drive it. The main idea is to achieve tracking of position and orientation while keeping the contact force within given bounds. A hyperbolic tangent approximation of the Heaviside function is used to switch mode between pure position and a hybrid force/position control. The control system is simulated for a 4-DOF serial chain.

This study presents an electromagnetic design methodology for a rotary magnetorheological (MR) fluid actuator. In order to improve the performance of the MR fluid actuator, the magnetic field should be effectively applied to the MR fluid. Therefore, it is important that the magnetic circuit composed of the MR fluid, the ferromagnetic material for magnetic flux path, and the electromagnetic coil is well designed. For this purpose, two effective approaches are proposed: one is to shorten the magnetic flux path by removing the unnecessary bulk of the yoke in order to improve the static characteristic of the MR fluid actuator, and the other is to increase the magnetic reluctance of the magnetic circuit by minimizing the cross-sectional area of the yoke through which the magnetic flux passes in order to improve the dynamic and hysteretic characteristics. The effectiveness of the proposed design methodology is verified through magnetic analysis and a series of basic experiments.

This paper deals with the improvement of the transparency of a 1-DOF (degree-of-freedom) hybrid haptic device with the wide-ranged torque reflection. The hybrid concept on the hybrid haptic device proposed in this study is focused on two points. One is to satisfy the transparency of the haptic device even for very small force reflection using compensation of the frictional component by the proposed actuation method. The other is to reflect the wide-ranged force with large workspace although it can exert very small output. In the structure, the hybrid haptic device follows the existing hybrid haptic device’s one – the combination of the active and passive actuators. In this study, the MR (magneto-rheological) brake as a passive actuator and the DC motor as a active actuator are used. The MR brake, which has the passivity property for the safety in interaction and the stability in control, is used as the main source for the reflective torque of the haptic device. On the other hand, the DC motor, which is active in nature, is used just for compensating the back-driven torques in the haptic system or providing additional torques for obtaining the output larger than the capacity of the MR brake. A series of the experimental results show the effectiveness and practicability of the proposed hybrid concept for the haptic device, directly or indirectly.

This paper presents a study on pressure control of capsule launching system using pneumatic source. Because the system has very fast dynamic characteristics, it is very difficult to control using control valve such as proportional valve. In this research, thus, control is passively achieved by the optimization of valve model instead of active control. The parameters to be optimized are viscous and elastic coefficients of the valve, and the method for optimization is selected as the genetic algorithm. Performance index is adopted to cost function that includes the characteristics of thrust pressure versus capsule displacement during launching time and launching efficiency. Optimization scheme and the result is shown, and thrust pressure trajectory and system characteristics obtained through optimized parameters of the valve is displayed.

For a model system consisted of four pneumatic cylinders with strokes of 10, 20, 40 and 80 mm, investigation was carried out experimentally and numerically about the reliability of system with elastic and viscous load. The elastic load affects the performance of each cylinder in cylinder series, and changes the time lag and the velocity of the piston, which makes the positioning control rather difficult. Taking the effects of the elastic load into consideration, positioning can be carried out comparatively smoothly by only adjusting the driving timing. The effect of a viscous load reduces the vibration of each moving body in the cylinder series and also reduces the over-travelled distance which happens when several cylinders move at the same time. For reasons, a positioning with a viscous load can be relatively smoothly carried out even without the timing control.

After the marine accident caused by an engine fire, IMO has established a separate regulation to prevent fire in the engine room. Accordingly, in order to prevent fire in a way that does not affect various electric devices in the engine room, a mist type water injection system was developed. This system includes mist type nozzle, engine room top piping system, water pump unit, fire monitoring system, etc.

I participated in the development of mist nozzles and developed a system for measuring and analyzing temperature inside a fire extinguishing test building for testing the fire extinguishing performance of various mist nozzles.

In addition, a hydraulic analysis was performed to deliver the pressure of water distributed to each mist nozzle to each end of the branch pipe above the minimum required pressure.

It is very important to accurately measure the amount of oil filled in the tanker. However, in general, the oil tank is filled with oil vapor that may be harmful to the human body, so it is difficult for the crew to directly enter the tank and measure it. To measure this at the top of the tank, a portable measuring device was developed. Inside the tank, there is some water in the bottom layer, an oil layer on it, and a vapor layer on the top. Using a proximity ultrasonic sensor, these media can be distinguished from the difference in impedance matching between the oil and vapor layers, and the water level at this time can be read from a tape measure coated with Teflon. In addition, the water in the lowermost layer is measured using a separate metal probe conductivity.