Yutaka Kondoh

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.

Actuators Making Use of Electro-Rheological Fluids: Movable Electrode Type ER Actuators:

By employing ER fluids as working fluids in fluid power systems, direct interface can be realized between electric signals and fluid power without the need for mechanical moving parts like spools in control valves. In this paper, first, novel 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 x 18 mm x 16 mm. Thirdly, a design method of R-METERA is described and a small sized R-METERA is fabricated, whose size is 067 mm x 53 mm. Principles of METERA are confirmed with the fabricated METERA.

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.

A Mini Valve in Application of Electro-Rheological Fluids

Abstract Electro-rheological fluids (ER fluids) allow direct interfacing between electric signals and fluid power without moving parts such as servo valves having spools driven by solenoids. In this paper, we apply ER fluids to fluid power control systems, especially to mini flow control valves (mini ER valves). A four-ports mini-ER valve whose size is 22mm cubic is manufactured, which can drives a small-sized piston cylinder at an amplitude of 0.5mm with a frequency of 2Hz or at an amplitude of 5mm with a frequency of 0.1Hz. It is confirmed that ER valves can be applied to micro valves.

Unsteady Flow Rate Measurement by Using Drag Force on Circular-Drag-Plate. Real Time Estimation by Using a Dynamic Modelling.

In this paper we propose an approach of unsteady flow rate measurement by using a drag-plate-type drag force flowmeter (DPFM). This type flowmeter has not been used as an unsteady flow rate sensor because the dynamic characteristics of this type flowmeter are not well known. In this study, we aim to realize an unsteady flow rate measurement with fast response and without expense. In this paper, we propose a simplified mathematical modelling of the DPFM, and real time unsteady flow rate measurement method using the dynamic modelling. As a calibration method, we employ cylindrical-choke-type instantaneous flowmeter (CCFM) and remote instantaneous flow rate measurement (RIFM). It is shown experimentally that the proposed unsteady flow rate measurement method is valid. Obtained results are as follows. As comparing the flow rate of the DPFM with that of the RIFM, first, the gain and phase characteristics of the DPFM show a good agreement within 1 dB and 10° with the RIFM over frequency range of 100 Hz, secondly, the DPFM demonstrates sufficient accuracy up to frequency of 400 Hz that is a resonant frequency of the beam system.