Motion control of pattern electrode by electrorheological fluids

The electrorheological (ER) behavior of suspensions was measured in nonuniform electric fields generated between pattern electrodes consisting of radial line and space. In spite of small areas of conductive parts on pattern electrodes, the suspensions show striking ER effects, which are comparable to those in uniform fields. The particles may be concentrated and the columns are fully developed between conductive lines. The striking ER effects can be attributed to the formation of columns with high particle concentrations. When the neighboring conductive lines on a fixed electrode are alternatively subjected to high voltage, other movable electrode causes the oscillating motion. Since the stable columns are always developed in direction parallel to the field vector, the excess dipolar interaction energy stored in inclined columns is relaxed by the arrangement of column conformation. For precise controls and rapid responses of motion, the thin and long columns should be developed between the electrode gap. In the process, the electrical energy is directly converted to mechanical motion. Therefore, the ER fluids have great potential as working fluids for a new type of actuators.