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.

We propose a novel liquid rate gyroscope using an electro-conjugate fluid in this study. The electro-conjugate fluid (ECF) is a dielectric fluid that works here as a functional/smart fluid generating a powerful jet flow (ECF jet) when subjected to high DC voltage. Using the ECF jet, we developed a liquid rate gyroscope based on the principle of a conventional gas rate sensor operated by Coriolis force. Because the ECF jet is generated only with a tiny electrode pair, the pumping part of proposed ECF gyroscope needs no mechanically moving parts, resulting in making the ECF gyroscope suitable for micro sensor compared to the gas rate sensor having a pumping mechanism inside. We fabricated a prototype of liquid rate gyroscope (40mm × 60mm × t7mm) and confirmed its characteristics by experiment. The experimental results confirm the effectiveness of the proposed liquid rate gyroscope. The scale factor of −29 mV/(°/s) is obtained with applied voltage of 4.5 kV.

A gyroscope is one of the most important mechanical components, used in wide variety of mechanical systems. Although many kinds of gyroscopes are commercially available, for consumer applications, lately becoming a big market for gyroscopes, a vibration gyroscope is the present standard. Vibration gyroscopes are small in size and low cost, however, they are not robust enough for external impact/vibration because they have vibrating elements inside.

This paper presents a new type of micromotor using electro-conjugate fluid (ECF). An electro-conjugate fluid is a kind of dielectric fluid, which works as a smart fluid. The fluid generates a powerful jet flow, which we call an ECF jet, when subjected to high DC voltage with highly non-uniform electric field, which means, it works as a fluid power source for mechanical components without bulky pumps. We introduce this attractive smart fluid to micromotors in this paper. Inside the motor is filled with the electro-conjugate fluid and a rotor has electrode pairs on the surface. By applying high DC voltage to the electrode pairs, the rotor rotates due to the ECF jet. In this paper, we design several types of electrode pairs and examine each influence on motor performances.

As a man-machine interaction increases its importance in robotics and mechatronics fields, a soft robot inspired from natural systems becomes one of the research trends. There are several research topics related to soft robots such as soft structures or artificial skins, compliance control, soft actuators or artificial muscles, and so on. For the natural muscle potentially has great flexibility, the authors believe the artificial muscle actuator must have a great potential in soft robots. Hence in this study we develop a new type of micro artificial muscle cell, which is an element of an integrated artificial muscle, using electro-conjugate fluid and measure its driving performances. In addition, position control characteristics are also clarified by experiments. As a result, the micro artificial muscle cell using electro-conjugate fluid shows quite good control performances

Soft robots inspired from natural systems are one of the main research topics in the robotic field since the last decade. Accordingly, artificial muscles were widely investigated due to their potentials in soft machines or soft robots. Many types of artificial muscles have been developed, including pneumatic actuators, ion-exchange polymer composite actuators, polymer gels, shape memory alloys, and so on. However, these artificial muscles are not used as practical actuators. In this study, the authors propose a new type of micro artificial muscle actuator (3) utilizing an electro-conjugate fluid (ECF) which generates a powerful jet flow when subjected to a high voltage (~ kV). The actuator basically consists of a fiber-reinforced silicone rubber tube and a micro pressure source using the ECF. The inner pressure of the silicone rubber tube is increased by the jet flow generated at the pressure source. The silicone rubber tube contracts along the actuator axis with the increasing pressure. The driving characteristics of the micro artificial muscle actuator were experimentally investigated. The experimental results show that this new actuation technology yields great potentials for driving soft robots.

By employing ER fluids as working fluids in fluid power systems, a direct interface can be realized between electric signals and fluid power without the need for mechanical moving parts like spools in control valves. In the paper, first, hydraulic actuators with ER fluids and with movable electrodes (METERA: movable electrode-type ER actuator) are proposed, which are classified into a linear type (L-METERA) and a rotary-type (R-METERA). Secondly, a design method of L-METERA is described and a small sized L-METERA is fabricated, whose size is 40 mm/spl times/18 mm/spl times/16 mm. Thirdly, a design method of R-METERA is described and a small sized R-METERA is fabricated, whose size is /spl phi/67 mm/spl times/53 mm. Principles of METERA are confirmed with the fabricated METERA.

To realize practical micromachines using fluid power with high power density, a micro fluid control system using homogeneous ER fluid is proposed and developed. Firstly, a new micro ER (electrorheological) valve using homogeneous ER fluid is proposed and fabricated. Its diameter is 9 mm. Static and dynamic characteristics are investigated. With supply pressure of 25 kPa and electric field strength change of 1.0 kV/mm, it is ascertained that the controllable pressure range is 10 kPa and the bandwidth is 0.5 Hz. Secondly, output characteristics of a resonantly-driven piezoelectric micropump 9 mm in diameter and 10 mm long are experimentally investigated by using homogeneous ER fluid. Maximum flow rate of 15 mm/sup 3//s and maximum pumping pressure of 0.2 MPa are obtained. Finally, an open-loop micro position control system is fabricated, which consists of the micropump, the micro ER valve and a bellows microactuator. Through basic experiments, it is confirmed that the output displacement of 23 /spl mu/m and the bandwidth of 0.3 Hz are realized.

To realize autonomous manipulators which work outdoors, 3D vision sensors having capability of real-time processing, robustness against sunlight, and compactness are required to measure objects and environments. In this paper a simple real-time motion stereo vision is proposed, which utilizes direct calculation of the integrated gradient constraint equation for sequential images taken by a motion camera. The vision sensor can measure 3D coordinates at every pixel without huge computation. The basic characteristics are investigated through indoor measuring experiments. The measuring accuracy of /spl plusmn/10% in a range of 0.7-1.5 m and the estimated measuring time of 0.7 s for 512 pixels /spl times/100 scanning lines are obtained. Then the performance of the proposed vision sensor are experimentally investigated under natural conditions including outdoors.

In this paper, first, a three-port micro ER valve (/spl phi/9.8 mm) is fabricated. Static characteristics of the micro ER valve are examined. The valve can produce load pressure change of 0.25 MPa at maximum electric field strength of 5 kV/mm. Secondly, a micro in-pipe mobile machine with the microvalves is fabricated, whose diameter and length are /spl phi/9.8 mm and 34.5 mm respectively. The microvalves control bellows-type microactuators and the in-pipe mobile machine moves like an inchworm. Performances of the in-pipe mobile machine are examined. The maximum average velocity obtained without a load is 0.9 mm/s.