The Experts below are selected from a list of 26115 Experts worldwide ranked by ideXlab platform
Shujiro Dohta - One of the best experts on this subject based on the ideXlab platform.
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Development of Flow Rate Control Type Quasi-Servo Valve Using Small-Sized On/Off Valves
2016 International Conference on Multimedia Systems and Signal Processing (ICMSSP), 2016Co-Authors: Masataka Yoneda, Tetsuya Akagi, Shujiro Dohta, Wataru Kobayashi, Yoshinori Moriwake, Feifei ChoAbstract:In a pneumatic driving system, a servo valve is most expensive equipment compared with pneumatic actuators. In a wearable driving system, the mass and size of a valve also becomes serious concern. The purpose of this study is to reduce the burden of the user by using a small and light-weight quasi-servo valve that consists of inexpensive on/off valves and an embedded controller. The relation between input duty ratio and Output Flow Rate of the valve is nonlinear. In the previous study, a pressure control type quasi-servo valve using a pressure transducer was also developed. However, the cost of the valve was increased. In this paper, to develop a lower-cost valve with good controllability, the Flow Rate control type quasi-servo valve by compensating the input duty-ratio of the valve is proposed and tested. The performance of the tested valve was also investigated. As a result, the valve can geneRate the proportional Output Flow Rate according to the input voltage.
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Development of Low-Cost Wearable Servo Valve Using Buckled Tube Driven by Servo Motor
Applied Mechanics and Materials, 2013Co-Authors: Abdul Nasir, Tetsuya Akagi, Shujiro Dohta, Ayumu Ono, Yusuke MasagoAbstract:Recently, power assisted nursing care systems have received much attention and those researches have been done actively. In such a control system, an actuator and a control valve are mounted on the human body. Designing the system, the size and weight of the valve become serious concerns. The purpose of our study is to develop a small-sized, lightweight and low-cost servo valve for precise control using wearable pneumatic actuators. In this study, a low-cost wearable servo valve that can control the Output Flow Rate by changing the twisted angle of the buckled tube in the servo valve is proposed and tested. The position control system of McKibben rubber artificial muscle using tested valve and embedded controller is also proposed and tested. As a result, we confirmed that the tested servo valve can control the Flow Rate in both supply and exhaust in an analog way. In addition, the estimated cost of the proposed valve can be reduced about 100 times cheaper (10 US Dollar) compared with the typical servo valve.
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Development of Small-Sized Digital Servo Valve for Wearable Pneumatic Actuator
Procedia Engineering, 2012Co-Authors: Shujiro Dohta, Tetsuya Akagi, Yusuke Masago, Hisashi Matsushita, Ying ZhangAbstract:Abstract Recently, power assisted nursing care systems have received much attention and those researches have been done actively. In such a control system, an actuator and a control valve are mounted on the human body. Designing the system, the size and weight of the valve become serious concerns. At the same time, the valve should be opeRated with lower energy consumption because of the limited electrical power. The purpose of our study is to develop a small-sized, lightweight and lower energy consumption control valve. In our previous study, a new type of fluid control valve with a self-holding function using a permanent magnetic ball in a check valve, a cylindrical magnet and two solenoids was also proposed and tested. In this study, a digital servo valve with self-holding function is proposed and investigated experimentally. As a result, we can confirm that the tested digital servo valve can control the Output Flow Rate in both supply and exhaust with low energy consumption.
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402 Development of Digital servo valve with Self-holding Function
The Proceedings of Conference of Chugoku-Shikoku Branch, 2011Co-Authors: Hirofumi Ueda, Tetsuya Akagi, Shujiro DohtaAbstract:Recently, power assisted nursing care systems have received much attention and active research. In such control system, an actuator and a control valve are mounted on the human body. In such designs, the size and weight of the valve become serious concerns. At the same time, the valve should be opeRated with lower energy consumption using limited electrical power. The purpose of our study is to develop a small-sized, lightweight and lower energy consumption control valve. In our previous study, a new type of fluid control valve with a self-holding function using a permanent magnetic ball in a check valve, a cylindrical magnet and two solenoids was also proposed and tested. In this study, a digital servo valve with self-holding function is proposed and tested. As a result, we can confirm that the tested digital servo valve can control Output Flow Rate in both supply and exhaust.
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Development and Analysis of Small-sized Quasi-servo Valve Using On/Off Valves
Proceedings of SICE Annual Conference 2010, 2010Co-Authors: Tetsuya Akagi, Feifei Zhao, Shujiro Dohta, Keiji FujitaAbstract:Today, the advanced age and less children society is growing up rapidly. The care and welfare equipments to support a nursing care and a self reliance of the senior and the disabled are actively researched and developed by many researchers. However, the power assisted device required many degrees of freedom. The total weight load of the wearable devices increases so that the number of actuator and control valves increases according to degrees of freedom. Therefore, we aim to develop a small and light-weight quasi-servo valve to decrease the burden of the user. In this paper, we proposed and tested a quasi-servo valve by using the small, light-weight and low cost on/off valves driven by the pulse width modulation method. The valve consists of two on/off valves and a microcomputer. Both valves are connected in serial. One valve is used as a switching valve to exhaust or supply, another is used as a PWM control valve that can adjust Output Flow Rate. And we confirmed that the Output Flow Rate of the tested valve could be adjusted in analog way. We also proposed the precise analytical model of the tested valve. By comparing the experimental result with the calculated results using the proposed model and the identified parameters, we could confirm that the model of the valve is valid. In addition, the optimal PWM period 5 ms of the tested valve could be obtained by the calculated result in pressure control simulation of the valve. In addition, the master slave bending control of the pneumatic flexible actuator using the quasi-servo valve was also proposed and tested. As a result, by using the tested valve and PID control method, the control performance of the system could be improved.
Tetsuya Akagi - One of the best experts on this subject based on the ideXlab platform.
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Development of Flow Rate Control Type Quasi-Servo Valve Using Small-Sized On/Off Valves
2016 International Conference on Multimedia Systems and Signal Processing (ICMSSP), 2016Co-Authors: Masataka Yoneda, Tetsuya Akagi, Shujiro Dohta, Wataru Kobayashi, Yoshinori Moriwake, Feifei ChoAbstract:In a pneumatic driving system, a servo valve is most expensive equipment compared with pneumatic actuators. In a wearable driving system, the mass and size of a valve also becomes serious concern. The purpose of this study is to reduce the burden of the user by using a small and light-weight quasi-servo valve that consists of inexpensive on/off valves and an embedded controller. The relation between input duty ratio and Output Flow Rate of the valve is nonlinear. In the previous study, a pressure control type quasi-servo valve using a pressure transducer was also developed. However, the cost of the valve was increased. In this paper, to develop a lower-cost valve with good controllability, the Flow Rate control type quasi-servo valve by compensating the input duty-ratio of the valve is proposed and tested. The performance of the tested valve was also investigated. As a result, the valve can geneRate the proportional Output Flow Rate according to the input voltage.
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Development of Low-Cost Wearable Servo Valve Using Buckled Tube Driven by Servo Motor
Applied Mechanics and Materials, 2013Co-Authors: Abdul Nasir, Tetsuya Akagi, Shujiro Dohta, Ayumu Ono, Yusuke MasagoAbstract:Recently, power assisted nursing care systems have received much attention and those researches have been done actively. In such a control system, an actuator and a control valve are mounted on the human body. Designing the system, the size and weight of the valve become serious concerns. The purpose of our study is to develop a small-sized, lightweight and low-cost servo valve for precise control using wearable pneumatic actuators. In this study, a low-cost wearable servo valve that can control the Output Flow Rate by changing the twisted angle of the buckled tube in the servo valve is proposed and tested. The position control system of McKibben rubber artificial muscle using tested valve and embedded controller is also proposed and tested. As a result, we confirmed that the tested servo valve can control the Flow Rate in both supply and exhaust in an analog way. In addition, the estimated cost of the proposed valve can be reduced about 100 times cheaper (10 US Dollar) compared with the typical servo valve.
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Development of Small-Sized Digital Servo Valve for Wearable Pneumatic Actuator
Procedia Engineering, 2012Co-Authors: Shujiro Dohta, Tetsuya Akagi, Yusuke Masago, Hisashi Matsushita, Ying ZhangAbstract:Abstract Recently, power assisted nursing care systems have received much attention and those researches have been done actively. In such a control system, an actuator and a control valve are mounted on the human body. Designing the system, the size and weight of the valve become serious concerns. At the same time, the valve should be opeRated with lower energy consumption because of the limited electrical power. The purpose of our study is to develop a small-sized, lightweight and lower energy consumption control valve. In our previous study, a new type of fluid control valve with a self-holding function using a permanent magnetic ball in a check valve, a cylindrical magnet and two solenoids was also proposed and tested. In this study, a digital servo valve with self-holding function is proposed and investigated experimentally. As a result, we can confirm that the tested digital servo valve can control the Output Flow Rate in both supply and exhaust with low energy consumption.
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402 Development of Digital servo valve with Self-holding Function
The Proceedings of Conference of Chugoku-Shikoku Branch, 2011Co-Authors: Hirofumi Ueda, Tetsuya Akagi, Shujiro DohtaAbstract:Recently, power assisted nursing care systems have received much attention and active research. In such control system, an actuator and a control valve are mounted on the human body. In such designs, the size and weight of the valve become serious concerns. At the same time, the valve should be opeRated with lower energy consumption using limited electrical power. The purpose of our study is to develop a small-sized, lightweight and lower energy consumption control valve. In our previous study, a new type of fluid control valve with a self-holding function using a permanent magnetic ball in a check valve, a cylindrical magnet and two solenoids was also proposed and tested. In this study, a digital servo valve with self-holding function is proposed and tested. As a result, we can confirm that the tested digital servo valve can control Output Flow Rate in both supply and exhaust.
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Development and Analysis of Small-sized Quasi-servo Valve Using On/Off Valves
Proceedings of SICE Annual Conference 2010, 2010Co-Authors: Tetsuya Akagi, Feifei Zhao, Shujiro Dohta, Keiji FujitaAbstract:Today, the advanced age and less children society is growing up rapidly. The care and welfare equipments to support a nursing care and a self reliance of the senior and the disabled are actively researched and developed by many researchers. However, the power assisted device required many degrees of freedom. The total weight load of the wearable devices increases so that the number of actuator and control valves increases according to degrees of freedom. Therefore, we aim to develop a small and light-weight quasi-servo valve to decrease the burden of the user. In this paper, we proposed and tested a quasi-servo valve by using the small, light-weight and low cost on/off valves driven by the pulse width modulation method. The valve consists of two on/off valves and a microcomputer. Both valves are connected in serial. One valve is used as a switching valve to exhaust or supply, another is used as a PWM control valve that can adjust Output Flow Rate. And we confirmed that the Output Flow Rate of the tested valve could be adjusted in analog way. We also proposed the precise analytical model of the tested valve. By comparing the experimental result with the calculated results using the proposed model and the identified parameters, we could confirm that the model of the valve is valid. In addition, the optimal PWM period 5 ms of the tested valve could be obtained by the calculated result in pressure control simulation of the valve. In addition, the master slave bending control of the pneumatic flexible actuator using the quasi-servo valve was also proposed and tested. As a result, by using the tested valve and PID control method, the control performance of the system could be improved.
Lasse Rosendahl - One of the best experts on this subject based on the ideXlab platform.
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Parametric study of a wave energy converter (Searaser) for Caspian Sea
Energy Procedia, 2018Co-Authors: Aliakbar Babajani, Mohammad T. Jafari, Parinaz Hafezisefat, Mojtaba Mirhosseini, Alireza Rezania, Lasse RosendahlAbstract:Abstract Over the past decades, different types of energy converters have been invented because wave energy is a renewable energy source with high potential for extraction of considerable clean energy. Many numerical and experimental tests have been conducted to calculate the power generation of ocean waves, and these tests have demonstRated the significance of this energy. In this paper, the hydrodynamic performance of a new energy converter called "Searaser" has been evaluated using numerical simulation to study different aspects of this energy converter. Since previous studies have found ocean wave energy converters excellent for implementation in the Caspian Sea, the aim of this study is to investigate its performance for that sea, so this study presents a numerical simulation of Searaser inside an experimental wave tank using commercial software Flow-3D. To model the motion of the energy converter, Reynolds Averaged Navier-Stokes was coupled with a volume-of-fluid (VOF) model to geneRate three-dimensional numerical linear propagating waves for solving the fluid field. Grid independency was also carried out to determine the best mesh numbers for the original simulations. Finally, the Searaser hydrodynamic performance was numerically calculated for different wave heights, and some of the most important parameters of point absorbers were captured, including Output Flow Rate in different seasons, extractable wave power, and Output power. Accordingly, the obtained results indicate that the Output Flow Rate and the power generation are significantly increased by incremental changes in wave height, and using this type of converter device has potential for practical and profitable use in industrial applications.
Aliakbar Babajani - One of the best experts on this subject based on the ideXlab platform.
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Parametric study of a wave energy converter (Searaser) for Caspian Sea
Energy Procedia, 2018Co-Authors: Aliakbar Babajani, Mohammad T. Jafari, Parinaz Hafezisefat, Mojtaba Mirhosseini, Alireza Rezania, Lasse RosendahlAbstract:Abstract Over the past decades, different types of energy converters have been invented because wave energy is a renewable energy source with high potential for extraction of considerable clean energy. Many numerical and experimental tests have been conducted to calculate the power generation of ocean waves, and these tests have demonstRated the significance of this energy. In this paper, the hydrodynamic performance of a new energy converter called "Searaser" has been evaluated using numerical simulation to study different aspects of this energy converter. Since previous studies have found ocean wave energy converters excellent for implementation in the Caspian Sea, the aim of this study is to investigate its performance for that sea, so this study presents a numerical simulation of Searaser inside an experimental wave tank using commercial software Flow-3D. To model the motion of the energy converter, Reynolds Averaged Navier-Stokes was coupled with a volume-of-fluid (VOF) model to geneRate three-dimensional numerical linear propagating waves for solving the fluid field. Grid independency was also carried out to determine the best mesh numbers for the original simulations. Finally, the Searaser hydrodynamic performance was numerically calculated for different wave heights, and some of the most important parameters of point absorbers were captured, including Output Flow Rate in different seasons, extractable wave power, and Output power. Accordingly, the obtained results indicate that the Output Flow Rate and the power generation are significantly increased by incremental changes in wave height, and using this type of converter device has potential for practical and profitable use in industrial applications.
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Hydrodynamic Performance of a Novel Ocean Wave Energy Converter
2018Co-Authors: Aliakbar BabajaniAbstract:Ocean waves are one of the energy resources which have potential to fulfil some parts of the world’s energy requirements. Recently, existing OWECs have been evaluated to find the most appropriate systems for the wave energy extraction of the Caspian Sea. Hence, point absorbers are found to be the most appropriate devices for this sea. Generally, the aim of this study is to study a novel ocean wave energy converter named “Searaser” which may be economical and practical for the Caspian Sea. Thus, this study presents a numerical simulation of Searaser inside a wave tank using commercial software (Flow-3D). In order to validate the simulations, the numerical and experimental results were compared with a point absorber and the both were in reasonable agreement. Afterwards, the performance of Searaser was numerically calculated for different heights of ocean waves. Accordingly, the obtained results indicate that the Output Flow Rate and the power generation increase significantly by increment of wave heights, and using this device may have the potential to be practical and profitable for industrial applications by improving its system.
Michael Yu Wang - One of the best experts on this subject based on the ideXlab platform.
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IROS - Novel Design of a Soft Pump Driven by Super-Coiled Polymer Artificial Muscles
2020 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2020Co-Authors: Yu Alexander Tse, Yang Yang, Ki Wan Wong, Michael Yu WangAbstract:The widespread use of fluidic actuation for soft robots creates a high demand for soft pumps and compressors. However, current off-the-shelf pumps are usually rigid, noisy, and cumbersome. As a result, it is hard to integRate most commercial pumps into soft robotic systems, which restricts the autonomy and portability of soft robots. This paper presents the novel design of a soft pump based on bellow structure and super-coiled polymer (SCP) artificial muscles. The pump is flexible, lightweight, modular, scalable, quiet, and low cost. The pumping mechanism and fabrication process of the proposed soft pump is demonstRated. A pump prototype is fabricated to verify the proposed design and characterize its performance. From the characterization results, the pump can reach an Output Flow Rate of up to 54 ml/min and delivers pressure up to 2.63 kPa. The pump has potential applications in untethered soft robots and wearable devices.
