Acoustic levitation positioning of objects in water

Applications for the precise three‐dimensional positioning of neutrally buoyant objects include the control of objects in space stations and the containerless processing of materials on Earth. There will be a demonstration of a microcomputer‐controlled system for acoustically levitating an object and moving it to any point within a three‐dimensional volume. The system uses a standing wave field in the vertical direction for levitation and a three‐transducer traveling wave field to displace the object in the horizontal directions via radiation force. Pulse‐echo transducers are used to provide continuous monitoring of position and a Macintosh Hex computer is used to control the position and provide user interfacing.