title: Triple degree-of-freedom piezoelectric ultrasonic micromotor via flexural-axial coupled vibration.
abstract: Actuators remain a limiting factor in robotics, especially in microrobotics where the power density of actuators is a problem. A 3 x 3 x 8.7 mm 3-axis piezoelectric ultrasonic micromotor system is described here in an effort to help solve this problem. Formed from 4 bulk lead zirconate titanate (PZT) thickness-polarized elements placed around the periphery of a rectangular rod, the stator is designed to combine axial and flexural vibrations in a way that permits rotation of a hardened steel ball as a rotor about an arbitrary axis. A simple prototype of the micromotor was found to produce at least a rotation speed of 10.4 rad/s with 4 microN-m torque about all 3 orthogonal directions at an excitation frequency of about 221 kHz, demonstrating the feasibility of a 3 degree-of-freedom millimeter-scale piezoelectric motor.
authors.affiliation: MicroNanophysics Research Laboratory, Department of Mechanical Engineering, Monash University, Clayton, Victoria, Australia.
authors.forename: Ter Fong
authors.initials: TF
authors.lastname: Khoo
authors.forename: Dinh Huy
authors.initials: DH
authors.lastname: Dang
authors.forename: James
authors.initials: J
authors.lastname: Friend
authors.forename: Denny
authors.initials: D
authors.lastname: Oetomo
authors.forename: Leslie
authors.initials: L
authors.lastname: Yeo
mesh_terms: D004867:Equipment Design; D007854:Lead / Q000737:chemistry*; D055616:Microtechnology / Q000295:instrumentation*; D015203:Reproducibility of Results; D012371:Robotics / Q000295:instrumentation*; D014025:Titanium / Q000737:chemistry*; D014741:Video Recording; D015040:Zirconium / Q000737:chemistry*
chemical_list: C065536:lead titanate zirconate; D007854:Lead; D015040:Zirconium; D014025:Titanium