Acoustic controlled rotation and orientation

US4800756A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Martin B. Barmatz · La Cañada Flintridge, US
• James L. Allen · La Cañada Flintridge, US

Key dates

• Filing date: Oct 29, 1986
• Grant date: Jan 31, 1989
• Expiry date: Oct 29, 2006

Classification

• Technology area (CPC G): Physics
• CPC primary: G10K15/00
• WIPO field: Other consumer goods
• WIPO sector: Other fields

Abstract

Acoustic energy is applied to a pair of locations spaced about a chamber, to control rotation of an object levitated in the chamber. Two acoustic transducers applying energy of a single acoustic mode, one at each location, can (one or both) serve to levitate the object in three dimensions as well as control its rotation. Slow rotation is achieved by initially establishing a large phase difference and/or pressure ratio of the acoustic waves, which is sufficient to turn the object by more than 45.degree., which is immediately followed by reducing the phase difference and/or pressure ratio to maintain slow rotation. A small phase difference and/or pressure ratio enables control of the angular orientation of the object without rotating it. The sphericity of an object can be measured by its response to the acoustic energy.