DYNAMIC SIMULATION OF A BIMODAL ULTRASONIC MOTOR BY NEW HYBRID LAPLACE TRANSFORM/FINITE ELEMENT METHOD

✍ Scribed by R.-F. FUNG; C.R. TSENG; C.-M. YAO

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 352 KB
• Volume: 226
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.1999.2309

✦ Synopsis

A new hybrid Laplace transform/"nite element method is proposed to solve the dynamic problem of a bimodal ultrasonic motor, which used a piezoelectric beam to drive the rotor. Two modes, longitudinal and #exural, of the piezoelectric beam are simultaneously excited by only one power ampli"er. A set of di!erential equations is derived by "nite element formulation for this oscillating beam. A proper similarity transform technique is used to decouple the Laplace transformed equations governing the vibration of the beam without contact and to make the inverse Laplace transformation easier. The contact problem between the beam and the rotor is also formulated and numerically solved. It is found that the simulation results obtained by using this hybrid method are almost identical with those by the Runge}Kutta method, but the former is able to avoid an excessive amount of computation time. Some important factors a!ecting the behavior of this motor are studied, including structure design, amplitude of input voltage, phase displacement, exciting frequency, gap between beam tip and rotor, and contact phenomena.