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×18 mm×16 mm. Thirdly, a design method of R-METERA is described and a small sized R-METERA is fabricated, whose size is φ67 mm×53 mm. Principles of METERA are confirmed with the fabricated METERA