Multiple-DOF Surface-Acoustic-Wave Piezoelectric Motors

Surface-acoustic-wave (SAW) piezoelectric motors capable of operating in multiple degrees of freedom (DOFs) simultaneously have been proposed. A particularly useful motor of this type could provide both linear and rotary motions. Another particularly useful motor of this type would feature a spherical joint that could be made to undergo controlled, simultaneous rotations about two orthogonal axes; such a motor could serve as a compact actuator in a joint of a robot arm and could be constructed as an integral part of the arm.