The Experts below are selected from a list of 1854 Experts worldwide ranked by ideXlab platform
Darwin G. Caldwell - One of the best experts on this subject based on the ideXlab platform.
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IROS - A 3-way valve-controlled spring assisted Rotary Actuator
2010 IEEE RSJ International Conference on Intelligent Robots and Systems, 2010Co-Authors: Yousheng Yang, Claudio Semini, Emanuele Guglielmino, Darwin G. CaldwellAbstract:Hydraulic Actuators are characterized by fast dynamics, high power density, high stiffness, large output force/torque, and in recent years are becoming increasingly attractive in the field of robotics. This paper presents the study of a 3-way proportional valve controlled, spring assisted electro-hydraulic Rotary Actuator, which consists of a 3-way proportional valve, a linear cylinder and a reciprocal spring. The operating principle is presented and a mathematical model is developed. Comparison analysis is made between the new Actuator and a traditional one with an application to a hydraulically actuated legged robot.
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A 3-way valve-controlled spring assisted Rotary Actuator
IEEE RSJ 2010 International Conference on Intelligent Robots and Systems IROS 2010 - Conference Proceedings, 2010Co-Authors: Yousheng Yang, Jian S. Dai, Claudio Semini, Emanuele Guglielmino, Darwin G. CaldwellAbstract:Hydraulic Actuators are characterized by fast dynamics, high power density, high stiffness, large output force/torque, and in recent years are becoming increasingly attractive in the field of robotics. This paper presents the study of a 3-way proportional valve controlled, spring assisted electro-hydraulic Rotary Actuator, which consists of a 3-way proportional valve, a linear cylinder and a reciprocal spring. The operating principle is presented and a mathematical model is developed. Comparison analysis is made between the new Actuator and a traditional one with an application to a hydraulically actuated legged robot.
Wenkang Wang - One of the best experts on this subject based on the ideXlab platform.
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A Wearable Soft Knee Exoskeleton Using Vacuum-Actuated Rotary Actuator
IEEE Access, 2020Co-Authors: Liancun Zhang, Qiang Huang, Zhiheng Wang, Wenkang WangAbstract:This study introduces a wearable soft knee exoskeleton that aids active knee motions during walking. It is mainly driven by vacuum-actuated Rotary Actuators. In this paper, the overall design of the exoskeleton is introduced. Moreover, the design of the vacuum-actuated Rotary Actuator is introduced, and the correspondence among the interior air pressure, rotation angle and output force of the Actuator under a vacuum condition and during the transition from the vacuum to an equal atmospheric pressure condition were studied. Then, the corresponding relations among the pressure, angle and torque of the Actuator were obtained to construct a knee torque model. Furthermore, we introduced in detail the control system of the exoskeleton, including a gait estimation model and knee torque model. The control system analysed knee angle information measured by IMUs and the air pressure of the Actuators measured by air pressure sensors. Then, by the calculations performed by both the gait estimation model and knee torque model, the corresponding commands for the aerodynamic switch, pressures and air flow rates were determined. According to the commands, a micro air pump and valves provided quantitatively positive or negative pressure for the Actuators to generate gait-consistent auxiliary torques, stretching torques and bending torques that were able to meet the needs of the knee during walking. Finally, a cardiopulmonary exercise test was used to quantitatively evaluate the exoskeleton. The results show that under the same load condition, the metabolic cost of walking is reduced by an average of 6.85% when the exoskeleton is worn.
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Design and Characterization of a Soft Vacuum-Actuated Rotary Actuator
Journal of Mechanisms and Robotics, 2019Co-Authors: Liancun Zhang, Qiang Huang, Wenkang WangAbstract:Abstract This study provides a type of soft vacuum-actuated Rotary Actuator. The structures in the Actuator are based on different elastomeric structures that comprise a number of interacting elastic radial beams, elastic circumferential beams, and interconnected, deformable sector ring structure air chambers. When negative pressure is applied to the structure, the radial beams bend reversibly into serpentine shapes until adjacent circumferential beams contact each other. This bending results in a large change in the circumferential angle of the structure, but a smaller change in its radial width. Thus, the structure produces rotational motion in its circumferential direction. The design, fabrication, and mechanical analysis of the Actuator are introduced, respectively. Moreover, finite element simulation analysis and experimental testing are carried out to study the corresponding relations between the air pressure, rotation angle, and force of the Actuator. In addition, the stimulation results and the experimental results of the Actuator are statistically analyzed by statistical product and service solutions (spss) statistical software. The test results of the experimental platform are highly correlated with the results of the finite element simulation.
Yousheng Yang - One of the best experts on this subject based on the ideXlab platform.
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IROS - A 3-way valve-controlled spring assisted Rotary Actuator
2010 IEEE RSJ International Conference on Intelligent Robots and Systems, 2010Co-Authors: Yousheng Yang, Claudio Semini, Emanuele Guglielmino, Darwin G. CaldwellAbstract:Hydraulic Actuators are characterized by fast dynamics, high power density, high stiffness, large output force/torque, and in recent years are becoming increasingly attractive in the field of robotics. This paper presents the study of a 3-way proportional valve controlled, spring assisted electro-hydraulic Rotary Actuator, which consists of a 3-way proportional valve, a linear cylinder and a reciprocal spring. The operating principle is presented and a mathematical model is developed. Comparison analysis is made between the new Actuator and a traditional one with an application to a hydraulically actuated legged robot.
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A 3-way valve-controlled spring assisted Rotary Actuator
IEEE RSJ 2010 International Conference on Intelligent Robots and Systems IROS 2010 - Conference Proceedings, 2010Co-Authors: Yousheng Yang, Jian S. Dai, Claudio Semini, Emanuele Guglielmino, Darwin G. CaldwellAbstract:Hydraulic Actuators are characterized by fast dynamics, high power density, high stiffness, large output force/torque, and in recent years are becoming increasingly attractive in the field of robotics. This paper presents the study of a 3-way proportional valve controlled, spring assisted electro-hydraulic Rotary Actuator, which consists of a 3-way proportional valve, a linear cylinder and a reciprocal spring. The operating principle is presented and a mathematical model is developed. Comparison analysis is made between the new Actuator and a traditional one with an application to a hydraulically actuated legged robot.
Liancun Zhang - One of the best experts on this subject based on the ideXlab platform.
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A Wearable Soft Knee Exoskeleton Using Vacuum-Actuated Rotary Actuator
IEEE Access, 2020Co-Authors: Liancun Zhang, Qiang Huang, Zhiheng Wang, Wenkang WangAbstract:This study introduces a wearable soft knee exoskeleton that aids active knee motions during walking. It is mainly driven by vacuum-actuated Rotary Actuators. In this paper, the overall design of the exoskeleton is introduced. Moreover, the design of the vacuum-actuated Rotary Actuator is introduced, and the correspondence among the interior air pressure, rotation angle and output force of the Actuator under a vacuum condition and during the transition from the vacuum to an equal atmospheric pressure condition were studied. Then, the corresponding relations among the pressure, angle and torque of the Actuator were obtained to construct a knee torque model. Furthermore, we introduced in detail the control system of the exoskeleton, including a gait estimation model and knee torque model. The control system analysed knee angle information measured by IMUs and the air pressure of the Actuators measured by air pressure sensors. Then, by the calculations performed by both the gait estimation model and knee torque model, the corresponding commands for the aerodynamic switch, pressures and air flow rates were determined. According to the commands, a micro air pump and valves provided quantitatively positive or negative pressure for the Actuators to generate gait-consistent auxiliary torques, stretching torques and bending torques that were able to meet the needs of the knee during walking. Finally, a cardiopulmonary exercise test was used to quantitatively evaluate the exoskeleton. The results show that under the same load condition, the metabolic cost of walking is reduced by an average of 6.85% when the exoskeleton is worn.
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Design and Characterization of a Soft Vacuum-Actuated Rotary Actuator
Journal of Mechanisms and Robotics, 2019Co-Authors: Liancun Zhang, Qiang Huang, Wenkang WangAbstract:Abstract This study provides a type of soft vacuum-actuated Rotary Actuator. The structures in the Actuator are based on different elastomeric structures that comprise a number of interacting elastic radial beams, elastic circumferential beams, and interconnected, deformable sector ring structure air chambers. When negative pressure is applied to the structure, the radial beams bend reversibly into serpentine shapes until adjacent circumferential beams contact each other. This bending results in a large change in the circumferential angle of the structure, but a smaller change in its radial width. Thus, the structure produces rotational motion in its circumferential direction. The design, fabrication, and mechanical analysis of the Actuator are introduced, respectively. Moreover, finite element simulation analysis and experimental testing are carried out to study the corresponding relations between the air pressure, rotation angle, and force of the Actuator. In addition, the stimulation results and the experimental results of the Actuator are statistically analyzed by statistical product and service solutions (spss) statistical software. The test results of the experimental platform are highly correlated with the results of the finite element simulation.
Kouhei Ohnishi - One of the best experts on this subject based on the ideXlab platform.
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Motion control of tendon-driven Rotary Actuator using Twist Drive system
2014 IEEE 13th International Workshop on Advanced Motion Control (AMC), 2014Co-Authors: Seiji Uozumi, Koyo Yu, Nobuto Yoshimura, Kouhei OhnishiAbstract:This paper proposes a method to achieve high-precision control for tendon driven system by using the Twist Drive. Twist Drive is one of transmission system which is consisted a pair of strings and Rotary motor. This transmission system converts torque into a pulling force by using the pair of strings twisted on each other. However, it cannot realize pushing motion. Therefore the Twist Drive needs to be combined with an other actuation system for the realization of pushing motion. The problem is solved by tendon drive using Twist Drive system in this paper. High-precision control is achieved by modal-space disturbance observer. Modal-space disturbance observer is designed to realize the acceleration based control. It also compensates the modal interference. Furthermore work space observer is able to estimate the force in the work space without any force sensors. The proposed method was applied to rotational angle control and torque control of the tendon driven Rotary Actuator. The effect of the proposal is verified through experiments.
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Realization of wire tension control for tendon-driven Rotary Actuator with a PE line
2010 IEEE International Symposium on Industrial Electronics, 2010Co-Authors: Yusuke Suzuki, Kouhei OhnishiAbstract:Recently, healthcare for elderly people is a big problem in certain countries. As the candidate to solve the problem, robots have been taking attention. The robots, which work in the nursing care field have to have multiple-degrees of freedom (DOF) to achieve variety of tasks. At the same time, the robots have to be small to work in limited space like human living environments. To achieve the goal, a new Rotary Actuator, which is small and output enough torque for operation is needed. Then a tendon-driven Rotary Actuator with polyethylene (PE) line was proposed in our previous study. However, the deflection of the PE line was occurred and the performance was deteriorated due to it during control. In this paper, new control systems for the tendon-driven Rotary Actuator with the PE line are proposed. The tension of the PE line is controlled in common mode and the rotation angle is controlled in differential mode with modal transformation. Moreover, the tension and the torque are also controlled with modal transformation. With the proposed control systems, the tension of the PE line is controlled in the intended value and the PE line is stretched tightly during the rotation angle control and the force control. The validity of the proposed tension control systems are evaluated through experiments.
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Development and verification of tendon-driven Rotary Actuator for haptics with flexible Actuators and a PE line
2010 11th IEEE International Workshop on Advanced Motion Control (AMC), 2010Co-Authors: Yusuke Suzuki, Hiroaki Kuwahara, Hiroyuki Tanaka, Kouhei OhnishiAbstract:In the future, robots will be important device widely in our daily lives to achieve complicated tasks. To achieve the tasks, there are some demands for the robots. In this paper, two strong demands of them are taken attention. First one is multiple-degrees of freedom (DOF), and the second one is miniaturization of the robots. Although Rotary Actuators is necessary to get multiple-DOF, miniaturization is difficult with Rotary motors which are usually utilized for multiple-DOF robots. Here, tendon-driven Rotary Actuator is a candidate to solve the problems of the Rotary Actuators. The authors proposed a type of tendon-driven Rotary Actuator using thrust wires. However, big mechanical loss and frictional loss occurred because of the complicated structure of connection points. As the solution for the problems, this paper proposes a tendon-driven Rotary Actuator for haptics with thrust wires and polyethylene (PE) line. In the proposed Rotary Actuator, a PE line is used in order to connect the tip points of thrust wires and the end effector. The validity of the proposed Rotary Actuator is evaluated by experiments.
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Achievement of precise force control for a tendon-driven Rotary Actuator with thrust wires and a PE line
IECON 2010 - 36th Annual Conference on IEEE Industrial Electronics Society, 2010Co-Authors: Yusuke Suzuki, Keisuke Sugawara, Kouhei OhnishiAbstract:Robots are taken attention as one of key solutions for nursing care field along with aging of population. In the nursing care field, the robots have to work in the limited space and contact with humans directly. Therefore miniaturization and precise force control are two important issues for nursing care robots. Then a tendon-driven Rotary Actuator with thrust wires and a polyethylene (PE) line was developed, and wire tension control system has been researched to solve the two important issues in our previous study. However, the Rotary Actuator did not show good force control performance due to the mechanical force loss in the thrust wires. In this paper, a force loss rate is identified, and compensation method for the tendon-driven Rotary Actuator is proposed with wire tension control in order to achieve precise force control. Compensation experiments are implemented to confirm the validity of the proposed method.
