Acta Medica Okayama0169-186424102010Development of an Intelligent Chair Tool System Applying New Intelligent Pneumatic Actuators15031528ENAhmad 'Athif MohdFaudziKoichiSuzumoriShuichiWakimotoThis paper develops an Intelligent Chair Tool (ICT) - a new chair-type human and machine interaction seating system powered by 36 intelligent pneumatic actuators. This tool can be used to facilitate investigation of chair shapes from spring and damping effects of seating and backrest surfaces. Each actuator used consists of five extensive elements of encoder, laser strip rod, pressure sensor, valves and PSoC microcontroller incorporated in a single device. By using the ICT, different shapes, spring and damping characteristics can be obtained to aid the design of chairs from the control inputs, i.e., position x, stiffness k(s) and viscous coefficient c. Several control algorithms are presented to realize the communication and control system, and to obtain all data in real-time. The control methodology presented contains an inner force loop and an outer position loop implemented using a unified control system. The specification, development design and experimental evaluation of the ICT control system and actuator used are presented and discussed.No potential conflict of interest relevant to this article was reported.Acta Medica Okayama0169-1864259-102011Miniature Pneumatic Curling Rubber Actuator Generating Bidirectional Motion with One Air-Supply Tube13111330ENShuichiWakimotoKoichiSuzumoriKeikoOguraSoft actuators driven by pneumatic pressure are promising actuators for mechanical systems in medical, biological, agriculture, welfare fields and so on, because they can ensure high safety for fragile objects from their low mechanical impedance. In this study, a new rubber pneumatic actuator made from silicone rubber was developed. Composed of one chamber and one air-supply tube, it can generate curling motion in two directions by using positive and negative pneumatic pressure. The rubber actuator, for generating bidirectional motion, was designed to achieve an efficient shape by nonlinear finite element method analysis, and was fabricated by a molding and rubber bonding process using excimer light. The fabricated actuator was able to generate curling motion in two directions successfully. The displacement and force characteristics of the actuator were measured by using a motion capture system and a load cell. As an example application of the actuator, a robotic soft hand with three actuators was constructed and its effectiveness was confirmed by experiments.No potential conflict of interest relevant to this article was reported.日本ロボット学会Acta Medica Okayama0289-18242972011大腸内視鏡挿入支援を目指したラバーチューブアクチュエータの設計と基礎駆動特性619625ENShuichiWakimotoKenOzakiKoichiSuzumoriColonoscopy is an important medical action to detect disorders like colon cancer. However generally it is difficult to insert a scope into the colon, because the colon is flexible and complex shape. This study aims at development of an actuator which can add propelling ability to a colonoscope. We focus on rubber pneumatic actuators, because advantages of them, for example, high compliance, low cost, water proof, and so on, agree with the required properties of medical devices. In this paper, we design a novel rubber actuator consisting of three air chambers by nonlinear FEM (finite element method) and fabricate the actuator employing the design by extrusion molding method. Basic characteristics of the actuator are clarified by a motion capture system, and functional motion leading assisting colonoscope insertion is observed. Actually using dummy endoscope, transportation ability by the actuators is confirmed experimentally and insertion experiments into a large intestine phantom are conducted.No potential conflict of interest relevant to this article was reported.日本設計工学会Acta Medica Okayama0919-29484692011空気圧剛性可変フィンガを有するバルーン型腱駆動ロボットハンドの開発517523ENJun-yaNagaseShuichiWakimotoNorihikoSagaKoichiSuzumoriNo potential conflict of interest relevant to this article was reported.IOP PublishingActa Medica Okayama0964-172620102011Design of a variable-stiffness robotic hand using pneumatic soft rubber actuatorsENJun-yaNagaseShuichiWakimotoToshiyukiSatohNorihikoSagaKoichiSuzumoriIn recent years, Japanese society has been ageing, engendering a labor shortage of young workers. Robots are therefore expected to be useful in performing tasks such as day-to-day support for elderly people. In particular, robots that are intended for use in the field of medical care and welfare are expected to be safe when operating in a human environment because they often come into contact with people. Furthermore, robots must perform various tasks such as regrasping, grasping of soft objects, and tasks using frictional force. Given these demands and circumstances, a tendon-driven robot hand with a stiffness changing finger has been developed. The finger surface stiffness can be altered by adjusting the input pressure depending on the task. Additionally, the coefficient of static friction can be altered by changing the surface stiffness merely by adjusting the input air pressure. This report describes the basic structure, driving mechanism, and basic properties of the proposed robot hand.No potential conflict of interest relevant to this article was reported.ElsevierActa Medica Okayama0924-42471641-22010Multiplex pneumatic control method for multi-drive system8894ENYasutakaNishiokaKoichiSuzumoriTakefumiKandaShuichiWakimotoPneumatic actuators have several advantages such as light weight safety low cost and high compliance However many pneumatic actuators have complicated systems that include a compressor air tubes and pneumatic valves with electrical wires This research proposes a new control method for a multiplex pneumatic transmission constructed with special resonant valves and air tubes with a control system driven by air vibration in air tubes without electrical wires The control is simplified and effective for pneumatic systems having many degrees of freedom In this paper the development of a primitive model of the resonant valve and a prototype valve is described In addition two control methods which are a superimposing method and a time-sharing method are shown and the independent driving of four actuators is realized by using one of the control methods with air tubes only.No potential conflict of interest relevant to this article was reported.MDPIActa Medica Okayama2076-08251032021Core-Shell Droplet Generation Device Using a Flexural Bolt-Clamped Langevin-Type Ultrasonic Transducer55ENKentaroOmoriGraduate School of Natural Science and Technology, Okayama UniversityNozomuFujimotoGraduate School of Natural Science and Technology, Okayama UniversityTakefumiKandaGraduate School of Natural Science and Technology, Okayama UniversityShuichiWakimotoGraduate School of Natural Science and Technology, Okayama UniversityNorihisaSenoGraduate School of Natural Science and Technology, Okayama UniversityDroplets with a core-shell structure formed from two immiscible liquids are used in various industrial field owing to their useful physical and chemical characteristics. Efficient generation of uniform core-shell droplets plays an important role in terms of productivity. In this study, monodisperse core-shell droplets were efficiently generated using a flexural bolt-clamped Langevin-type transducer and two micropore plates. Water and silicone oil were used as core and shell phases, respectively, to form core-shell droplets in air. When the applied pressure of the core phase, the applied pressure of the shell phase, and the vibration velocity in the micropore were 200 kPa, 150 kPa, and 8.2 mm/s, respectively, the average diameter and coefficient of variation of the droplets were 207.7 mu m and 1.6%, respectively. A production rate of 29,000 core-shell droplets per second was achieved. This result shows that the developed device is effective for generating monodisperse core-shell droplets.No potential conflict of interest relevant to this article was reported.MDPIActa Medica Okayama1424-82202292022Displacement Sensing of an Active String Actuator Using a Step-Index Multimode Optical Fiber Sensor3232ENWeihangTianGraduate School of Natural Science and Technology, Okayama UniversityShuichiWakimotoGraduate School of Natural Science and Technology, Okayama UniversityTakefumiKandaGraduate School of Natural Science and Technology, Okayama UniversityDaisukeYamaguchiGraduate School of Natural Science and Technology, Okayama UniversityA thin McKibben artificial muscle is a pneumatic actuator with an outer diameter of only 1.8 mm. We fabricated a string-shaped actuator called an "active string actuator," which achieves a high contractile displacement by accumulating thin McKibben artificial muscles. To control the displacement, the length of the active string actuator should be estimated. However, this is difficult because bulky and rigid sensors are unsuitable for the sensor element of the active string actuator. Therefore, in this study, we propose a new sensing method for estimating the length of an active string actuator. The proposed sensing system is simple and comprises only three components: a step-index multimode optical fiber, a light emitter, and a light receiver. A step-index multimode optical fiber was combined with the active string actuator, and the length was estimated from the change in the amount of light propagating in the optical fiber when the active string actuator was driven. Fundamental experiments were conducted in this study, and the results demonstrated that the optical fiber sensor value changed with the actuator length. This suggests that it is possible to estimate the displacement of an active string actuator using an optical fiber sensor.No potential conflict of interest relevant to this article was reported.IOP PublishingActa Medica Okayama0021-49226332024Evaluation of transducer for cryogenic actuators by equivalent circuit model03SP03ENKazukiKuboGraduate School of Environment, Life, Natural, Science and Technology, Okayama UniversityKairiYagiGraduate School of Environment, Life, Natural, Science and Technology, Okayama UniversityTakefumiKandaGraduate School of Environment, Life, Natural, Science and Technology, Okayama UniversityKoaYasudaGraduate School of Environment, Life, Natural, Science and Technology, Okayama UniversityDaisukeYamaguchiGraduate School of Environment, Life, Natural, Science and Technology, Okayama UniversityShuichiWakimotoGraduate School of Environment, Life, Natural, Science and Technology, Okayama UniversityCryogenic environments are increasingly used in scientific and industrial fields. Recently, cryogenic environments are also used for storage and supply of liquid hydrogen, which is considered essential for the realization of a decarbonized society. Actuators to drive a valve that controls such a low-temperature fluid are required. In this study, a piezoelectric transducer that can be driven in the cryogenic environment has been fabricated and evaluated. Although the performance of piezoelectric elements degrades at cryogenic temperatures in general, the application of a preload can suppress the degradation of performance. Equivalent circuits were used for evaluation, and force factors and figures of merit were compared. As a result, the force factor was as high as that at RT even at cryogenic temperatures, and a high figure of merit was obtained. The result indicates that the transducer can be used for the driving of micro actuator at cryogenic temperature.No potential conflict of interest relevant to this article was reported.