Magnetostrictive direct drive rotary motor development

Highly Magnetostrictive materials such as Tb/sub 0.3/Dy/sub 0.7/Fe/sub 2/, commercially known as Terfenol-D, have been used to date in a variety of devices such as high-power actuators and linear motors. The larger magnetostriction available in twinned single-crystal Terfenol-D, approximately 2000 p.p.m. at moderate magnetic field strengths, makes possible a new generation of magneto-mechanical devices. The authors are investigating the potential of this material as the basis of a direct micro-stepping rotary motor. Such a motor would be a high torque micro-radian stepper, capable of precision movements and self-braking in the power off state. A motor prototype being developed based on the proven 'inch worm' technique is presented. Results of mathematical modeling techniques are presented, including magnetic, structural, and both linear and nonlinear dynamic calculations.<
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