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Laparoscopic choledochotomy on patients indicated for common bile duct exploration was carried out according to an algorithm for managing choledocholithiasis. This study describes retrospectively our method and evaluates a new cystic duct biliary decompression cannula (J-tube) as an alternative to the T-tube.Patients with confirmed choledocholithiasis (n=46) underwent laparoscopic choledochotomy. The T-tube was inserted in cases with suspected retained stones after common bile duct clearance, and the J-tube (950-mm long, 4 Fr) with a tapered and J-shaped segment at the distal end was inserted in other cases.Only 1 case was converted to open surgery (success rate, 97.8%); the J-tube was inserted in 30 patients and the T-tube in 15. The median operation time, hospital stay, and the interval until removal of the tube were significantly shorter with J-tube than with T-tube cases. Bile leakage after surgery occurred in 4 J-tube and 2 T-tube cases with one residual stone in each case.The transcystic decompression tube is easily and safely inserted with the J-kit. Among several strategies currently available for the management of choledocholithiasis, laparoscopic choledochotomy with the use of the J-tube is one of the safest and most feasible methods.

Background: Multiple colon polyps and early cancers are often detected at colonoscopy, but we could not collect all polypectomied specimens in one insertion of a colonoscope. Endoscopic mucosal resection (EMR) may often be very difficult for the collection of the size, type, form, or location of the polyps. Methods: We performed EMR to collect plural polypectomied specimens by a modified new technique using a clip connected with a string in 40 patients (25 male, 15 female) who visited Saiseikai Nakatsu Hospital and Mitsubishi Kobe Hospital for colonoscopic treatment. The method was as follows: (i) insert a colonoscope; (ii) check polyps by indigocarmine pigmentation and endoscopic ultrasonography (EUS); (iii) check the lift-up sign by submucosal injection of 2.5% hypersaline-epinephrine containing indigocarmine; (iv) make a clip connected with string (Tegusu-3 go) and insert the clip kit through the channel of the colonoscope; (v) clip the polyp; (vi) insert snare in the channel of an endoscope, passing the string through the center of the snare; (vii) snare the polyp with counter traction of string and cutting by bipolar electric power; (viii) check for bleeding. If there is bleeding from the polypectomied site, another clip is necessary; and (ix) collect polyp. If there are many polyps, flags connecting the string are required. Results and Conclusion: All polyps were treated and collected in all patients by one insertion of the colonoscope without complications. Our modified EMR method was useful in the collection of multiple polypectomied polyps.

A classifier system for the reinforcement learning control of autonomous mobile robots is proposed. The classifier system contains action selection, rules reproduction, and credit assignment mechanisms. An important feature of the classifier system is that it operates with continuous sensor and action spaces. The system is applied to the control of mobile robots. The local controllers use independent classifiers specified at the wheel-level. The controllers work autonomously, and with respect to each other represent dynamic systems connected through the external environment. The feasibility of the proposed system is tested in an experiment with a Khepera robot. It is shown that some patterns of global behavior can emerge from locally organized classifiers.

An autonomous robot that acts in a complex environment needs to learn which action should be performed in each external state. Therefore, we propose a new control architecture for autonomous robots. The control architecture includes a learning system, which consists of globally coupled chaotic elements. A chaotic element has dynamics which are designed so that the elements can collectively execute reinforcement learning. Although each element continuously updates its internal state according to its intrinsic dynamics, this local processing collectively determines an action of the robot and allows it to interact with its environment. The result of this interaction returns to the elements as a payoff, which changes the dynamics. We carried out computational experiments for a navigation task. The results show that the chaotic elements self-organize so that an autonomous mobile robot exhibits such behaviors as goal-reaching, wall-following and collision avoidance.

In order to reach a better productivity in numerous fields, robots have been wildly used for automatic tasks. The main issue of a robot is his lack of adaptability, which is one of the most important ability of human beings. The best tool for adaptability is the human hand. Using pneumatic actuators to drive a robot forearm grants the possibility to move light articles with accuracy and without harming it. It is then necessary to develop accurate model of the different types of actuators. As every human muscle are simulated by those actuators, the size of these must vary and so their properties as well. These artificial muscle-type pneumatic actuators are composed of a rubber balloon, a net, a feeding channel and finally two anchors at both end of the net. Starting with the simplest linear model, we increased the complexity of the model to finally obtain a powerful control of the plastic muscle. To obtain the data we needed for the model, we used a test bench for pneumatic actuators and adjust it to fit the new size of the current actuator. The main difficulty to control the actuator is to find a way to overcome its hysteresis cycle. Then once the model is ready we need to use it to control the different part of the pneumatic forearm. The previous wrist and hand control is enhanced by feed forward control and can perform motion with a great accuracy. The hand can therefore be used without any electronic devices on it and remains lighter and safer. Previous starting dead-zone has been understood and avoided.Copyright © 2012 by ASME

Recently, research and development in robotics have focused on robots performing tasks traditionally done by people. Therefore, it is necessary for robots to have the same flexibility as people. Additionally, such robots need to incorporate high-level safety features so as not to incur injury on others. We present artificial muscle-type pneumatic actuators as the driving source of a robot hand that is both safe and flexible. Development of robot hands using pneumatic actuators has already taken place. However, when a pneumatic actuator is used, a large compressor is needed. Therefore, the driving system also needs to be large. This is a major problem. Therefore, we developed low-pressure, low-volume pneumatic actuators for driving a robot hand that works flexibly and safely among people and a five-fingered robot hand with these pneumatic actuators installed. To accurately control the five-fingered robot hand, an accurate model with a pneumatic actuator is needed. We constructed such a model by using a spring element, which expresses the generative force of pneumatic pressure, and a damper element, which expresses the hysteresis characteristics. We then made a 1-link arm that has one degree of freedom using the pneumatic actuators and constructed a 1-link armmodel. We also constructed a spring-damper element model of the pneumatic actuators and a proportional-integral-derivative (PID) controller system. The gains of the system were determined with a simulation that uses our 1-link arm model. The step response of the joint angle was examined with these determined gains.

In recently years, the production method has changed from the diversification of a sense of values from mass production to diverse-types-and-small-quantity production on the production site. Therefore, a productive system that can correspond to changes in the environment is required. In a productive system that performs handling tasks, we use a hand-eye system with a camera and a manipulator and perform hand-eye calibration from two dimension images obtained by camera to the manipulator coordinates a three dimension system of in the hand-eye system. However, the camera and the manipulator positions in the previous system changed, and great error from the position, which performed the calibration, was caused even when the error was minute. Therefore, in this hand-eye system, changing this production system is difficult or re-calibration is needed. The projection matrix must be calculated so that the image coordinates obtained with the camera and the manipulator coordinates of three dimensions correspond again in the re-calibration. However, calculating the projection matrix requires great care. We propose a technique that simply calculates the manipulator coordinates of three dimensions from image coordinates without calculating the projection matrix again by correcting the image coordinates. Our experiment results show that the image coordinates can be corrected without calculating the projection matrix again using a landmark. In addition, a three-dimensional position was corrected simply, and we were able to handle the object.

To cope with the flexibility for diversifications of products and shortened life cycles of goods and the adaptability to occurrence of unexpected events like machine troubles and task changes, BMS (Biological-Oriented Manufacturing Systems) is recently proposed as a new concept beyond existing CIM. In this study, a manufacturing ribosome model is developed as the first step to realize the BMS concept. The manufacturing ribosome is a basic structure element in the BMS, and is provided with at least three functions, transformation, transportation and verification. This paper describes a developed prototype of manufacturing ribosome and discusses it in terms of flexibility and autonomy. Finally, a realization of the transformation included in manufacturing ribosome and case study are carried out.