Flat rotary motors made of lead-zirconate-titanate. (Materials Science/R&D).

Advanced Materials & Processes, April, 2003

A low-cost, high-torque, flat rotary motor made of flexible strips of lead-zirconate-titanate (PZT) has reportedly been developed by the Pennsylvania State University, University Park, Pa PZT is an inexpensive, commonly available piezoelectric material that elongates when an electric field is applied.

When PZT is bonded to both sides of a small, flexible metallic strip, the strip becomes an arm that bends to the left and right in response to an electric field. To make the motor, which is about 14 cm (5.5 in.) square and about 0.5 cm (0.25 in.) thick, 12 of the arms are placed around a central shaft. When stimulated simultaneously, they all bend in the same direction. A passive damping system, either a ball-and-spring arrangement or a commercial one-way roller...