Closed loop electrostatic levitation system

US4521854A · kind A · utility

Assignee

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

Inventors

• Won-Kyu Rhim · Pasadena, US
• Melvin M. Saffren · Altadena, US
• Daniel D. Elleman · San Marino, US

Key dates

• Filing date: Oct 29, 1982
• Grant date: Jun 4, 1985
• Expiry date: Oct 29, 2002

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T74/1275
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

An electrostatic levitation system is described, which can closely control the position of objects of appreciable size. A plurality of electrodes surround the desired position of an electrostatically charged object, the position of the object is monitored, and the voltages applied to the electrodes are varied to hold the object at a desired position. In one system, the object is suspended above a plate-like electrode (16, FIG. 1) which has a concave upper face (26) to urge the object toward the vertical axis (20) of the curved plate. An upper electrode (18) that is also curved can be positioned above the object, to assure curvature of the field at any height above the lower plate. In another system, four spherical electrodes (81-84, FIG. 6) are positioned at the points of a tetrahedron, and the voltages applied to the electrodes are varied in accordance with the object position as detected by two sensors (94,96 FIG. 4).