TOWARD NEW CYLINDRICAL ELECTROSTATIC MICROMOTORS USING TUBULAR COMBINATION OF ARRAYED DIRECT-DRIVE ACTUATORS

A new generation of electrostatic micromotors is investigated using co operation of arrayed direct-drive actuators. Electrostatic scratch-dri ve actuators (SDAs), which combine active frictional contact mechanism s with electrostatic actuation are particularly analyzed. A prototype of a cylindrical micromotor, whose external diameter and length are, r espectively, 1 mm and 2 mm, has been realized through the insertion of a flexible active polysilicon sheet at the rotor/motor-frame interfac e. The sheet, which acts as a stator, is fabricated by the surface mic romachining process and then released automatically from the silicon w afer. One thousand four hundred thirty actuators are integrated on a 6 mm(2) polysilicon sheet surface, leading to high-driving-torque chara cteristics.