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Nishi-Tokyo-shi, Japan

Yokota S.,Tokyo Institute of Technology | Yajima F.,Tokyo Institute of Technology | Takemura K.,Keio University | Edamura K.,New Technology Management Co.
Advanced Robotics | Year: 2010

An electro-conjugate fluid (ECF) is a type of dielectric and functional fluid that generates a powerful jet flow when subjected to high DC voltage. Although a high voltage is needed to generate the jet flow, the current is quite low at several microamperes, resulting in a total power consumption of several milliwatts. Using this smart fluid, we can develop micro fluid-driven mechanical components without any bulky pumps. Also, it is clarified that the power density of the ECF jet is higher when the electrode pair is miniaturized; therefore, it is suitable for micro actuators. Here, we propose and fabricate three types of soft actuators with an antagonistic configuration: (i) micro artificial muscle cells, (ii) a McKibben-type micro artificial muscle actuator using the ECF effect and (iii) a micro finger actuator with two chambers to bend. The actuators basically consist of a silicone rubber tube covered with a fiber sleeve and a micro pressure source using the ECF effect. Next, we apply and integrate these actuators into a micro robot hand, driven with ECF jets. The driving characteristics of the micro artificial muscle actuator and the integrated micro ECF hand with ECF fingers were fabricated and experimentally investigated. The experimental results show that this ECF jet actuation is effective for driving soft micro hands. © 2010 VSP. Source


Mori K.,Keio University | Yamaguchi A.,Keio University | Takemura K.,Keio University | Yokota S.,Tokyo Institute of Technology | Edamura K.,New Technology Management Co.
Sensors and Actuators, A: Physical | Year: 2012

An electro-conjugate fluid (ECF) is a kind of functional fluid, which produces a powerful flow when subjected to high DC voltage. It is known that a strong ECF flow is generated under non-uniform electric field, for example, the field with a pair of needle and ring electrodes. The ECF flow could be used as a micro fluid pressure source (an ECF pump) for actuators including an artificial muscle and a flexible finger. However, previous studies on ECF soft actuators only focused on confirmation of the driving principle. This means, an improvement of performance of ECF pumps and a control scheme for ECF soft actuators have yet to be studied in detail. Hence, this study improves the performance of the ECF pump, and proposes a novel control system for an ECF flexible finger. The ECF pump developed in this study, 200.3 mm 3, generates maximum pressure of 92.6 kPa and maximum flow rate of 103.0 ml/min. The flexible finger (Ø 5 mm ×30mm), driven by the ECF pump, bends 150° with a rise time of 1 s. In addition, we construct a master-slave system using the ECF flexible finger and confirm its performance. © 2012 Elsevier B.V. All rights reserved. Source


Yamaguchi A.,Keio University | Takemura K.,Keio University | Yokota S.,Tokyo Institute of Technology | Edamura K.,New Technology Management Co.
Sensors and Actuators, A: Physical | Year: 2012

An electro-conjugate fluid (ECF) is a kind of functional fluid, which produces a jet flow (ECF jet) when subjected to high DC voltage. It is known that a strong ECF jet is generated under nonuniform electric field, for example, the field with a pair of needle and ring electrodes. We developed in our previous study a novel five-fingered flexible robot hand using the ECF. In this study, in order to improve the ECF hand we pay our attention to the flexion of palm because human often grasp an object with the flexion of palm. First, we propose a concept of five fingered robot hand which has balloon actuators driven by the ECF jet to produce the flexion of palm. The actuator is mainly composed of silicone rubber membrane and a rubber base with a slit, so that when the actuator is pressurized, the slit is opened, resulting in making the palm of the robot hand actuate. Finally we conduct grasping experiments based on Cutkosky's taxonomy of human grasping, and demonstrate the robot hand can grasp some objects with various shapes without any complex controller. The height, the width and the mass of the robot hand are approximately 70 mm, 40 mm and 40 g, respectively. © 2011 Elsevier B.V. All rights reserved. Source


Ueno S.,Keio University | Takemura K.,Keio University | Yokota S.,Tokyo Institute of Technology | Edamura K.,New Technology Management Co.
Sensors and Actuators, A: Physical | Year: 2014

An electro-conjugate fluid (ECF) is a kind of functional fluid, which produces a flow (ECF flow) when high DC voltage is subjected. Since it only requires a tiny electrode pair in micrometer-scale size in order to generate ECF flow, ECF is a promising micro fluid pressure source. Hence, by using ECF as the power source, we realize a micro inchworm robot. In this study, first, we have proposed the concept of a novel micro inchworm robot driven by the ECF. Second, we have designed, fabricated and characterized each component of the micro robot. Third, we have developed the micro inchworm robot by using each component. The length, width and mass of the micro robot are approximately 23 mm, 8.5 mm and 1.9 g, respectively. Finally, we observed the characteristics of micro robot with conducting an experiment. Experimental results proved that the micro robot could move on a horizontal acrylic surface with maximum speed of 5.2 mm/s. The micro robot has superior ability in migration speed, compared with previously developed micro inchworm robots. © 2014 Elsevier B.V. Source


Yamaguchi A.,Keio University | Takemura K.,Keio University | Yokota S.,Tokyo Institute of Technology | Edamura K.,New Technology Management Co.
Proceedings - IEEE International Conference on Robotics and Automation | Year: 2011

An electro-conjugate fluid (ECF) is a kind of functional fluid, which produces a jet flow (ECF jet) when subjected to high DC voltage. It is known that a strong ECF jet is generated under nonuniform electric field, for example, the field with a pair of needle and ring electrodes. This study introduces the ECF jet to develop a novel flexible robot hand. First, we characterize the ECF jet generator which could be a micro fluid pressure source of the robot hand, and confirm the effect of the variation of electrode parameters and the number of electrode pairs on its performance. Next, we investigate the characteristics of the robot finger which mainly consists of the ECF jet generator, a flexible rubber finger and an ECF tank. The robot finger is integrated with the pressure source (ECF jet generator) and the tank, and is successfully driven. Finally we developed a five-fingered flexible robot hand and demonstrate that the robot hand can grasp some objects with various shapes without any complex controller. The height, the width and the mass of the robot hand are approximately 60 mm, 40 mm and 15 g, respectively. © 2011 IEEE. Source

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