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.
Electrorheological Properties of Suspensions of Inorganic Shell/Organic Core Composite Particles
Abstract Composite particles consisting of a polymer core and inorganic shell are formed by suspension polymerization. The electrorheological (ER) behavior of the suspensions is studied in relation to surface conditions. When the composite particles are subjected to jet-stream agitation, the ER effects are strikingly enhanced. Although the inorganic shell on the polymer particles is responsible for the ER effect, the impurities which were derived from the polymerization reaction must be removed from the surfaces. The suspensions are nonconducting, even though the polymer cores are coated with conducting particles. In composite particles, the thin layer of polymer prevents direct contact of inorganic particles which are arranged in layers on the polymer core. Since the density of composite particles is comparable to that of oil, the suspensions have long-term stability against sedimentation.
New approach to vision-based BGA package inspection
Ball grid array (BGA) techniques have developed very fast due to the advantages of more I/O ports, small size, and so on. In this paper, a vision-based algorithm for BGA package inspection is proposed to accurately estimate center and diameters of solder-balls of BGA packages, so that defects of BGA packages, such as missing or extra balls, oversize or undersize balls, over-height or under-height balls, and pitch can be detected for ensuring the quality of BGA packages.