FERROHYDRODYNAMIC SENSOR DEVELOPMENT.
Abstract
In inertial sensors many refinements can be employed to compensate for errors arising from sources other than mechanical friction. The erratic nature of mechanical friction precludes the use of compensation and accounts for the largest single source of error in seismic instruments. With the long range objective of eliminating mechanical friction, this study applies the novel concept of levitational support by a ferromagnetic fluid to obtain free suspension of the test mass of an integrating accelerometer. Analysis of the levitational force and its dependence on permeability, applied field, and geometry is developed from the starting point of the stress tensor for the magnetic medium. The theory of the instrument is presented and an experimental accelerometer including an electrostatic pick off is designed, constructed, and tested. As the result it is confirmed that levitation is achieved with no source of power. A restoring force of 300 dynes is experienced by a cylindrical proof mass having a diameter of 1.8 cm and length of 2.0 cm. A threshold of less than 10 micro g was demonstrated, with spurious inputs in the laboratory preventing measurements at lower levels. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1968
- Accession Number
- AD0835436
Entities
People
- G. Miskolczy
- J. J. Pellegrino
- R. E. Rosensweig
- R. Litte