Damping control for positioning apparatus
US3940676A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 11, 1974 |
| Grant date | Feb 24, 1976 |
| Priority date | — |
| Expiry date | Oct 11, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K2201/18
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A positioning apparatus includes a platen and a head independently movable relative to the platen. First and second coils having a particular phase relationship are disposed relative to each other on the head are independently energized to produce first and second electromagnetic forces. These electromagnetic forces have varying characteristics for moving the head relative to the platen and constant characteristics for maintaining the head in a substantially fixed relationship to the platen. Abrupt changes from the variable to the constant characteristics of the applied electromotive forces allow inertial forces to impart a decaying oscillation of the head about the positional origin determined by the constant characteristics of the applied electromotive force. Oscillation of the head relative to the platen produces first and second back-electromotive force sinusoids in the first and second coils, respectively. Means is provided for detecting the first back-electromotive force sinusoid to produce a damping signal with characteristics similar to the characteristics of the second back-electromotive force sinusoid. This damping signal can be introduced to the second coil to damp the s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.