Movable electrode-type ER actuators (proposal of linear-type and rotary-type METERA)
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.
Micro in-pipe mobile machines by making use of an electro-rheological fluid
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.
AN IN-PIPE MOBILE MICROMACHINE USING FLUID POWER TRAVERSABLE BRANCHED PIPES
In-pipe mobile micromachines have many applications including micro maintenance robots for nuclear reactors and are expected to be realized in the near future. For practical micromachines, the authors have proposed the bellows microactuator using fluid power with high power density. In this paper, an inchworm type in-pipe mobile micromachine which is traversable branched pipes using the bellows microactuators is fabricated and the performance is examined. Firstly, performance of displacement magnification mechanisms significant for micromachines is theoretically investigated and the effectiveness of a pulley type mechanism is proved. Secondly, for structure of an in-pipe mobile micromachine, a bending and propelling mechanism with 1-bending DOF using pulley type mechanisms is proposed and the traveling sequence in branched pipes is theoretically investigated. Finally, an in-pipe mobile machine with 25mm in diameter is fabricated and the traveling experiments are conducted. It is clarified that the traveling velocity in a straight pipe is increased and the fabricated machine is able to traverse a Y-shaped pipe.