Magnetic bearings for a spaceflight optical disk recorder

The development and testing of a magnetic bearing system for the translator of the read/write head in a magneto-optic disk drive are discussed. The asymmetrical three-pole actuators with permanent magnet bias support the optical head, and its tracking and focusing servos, through their radial excursion above the disk. The specifications for the magnetic bearing are presented, along with the configuration of the magnetic hardware. Development of a five degree of freedom collision model is examined which allowed assessment of the system response during large scale transients. Experimental findings and the results of performance testing are presented, including the roll-off of current-to-force due to eddy current loss in the magnetic materials.