Merchant, Gould, Smith, Edell, Welter & Schmidt
Sensing and controlling the location of elements of a linear motor
 A system for detecting movement of a forcer of a motor directed for effecting movement of a forcer in a first direction in response to command pulses. There is a toothed platen for locating the forcer so that the forcer is movable over the platen. A magnetic structure is attached to move with the forcer and has a periodic configuration corresponding to the forcer and in magnetic interchange relation to the platen. A magnetic circuit is associated with the magnetic structure. Flux sensors generate signal variations corresponding to flux variations as the forcer moves relative to the teeth of the platen. The signal variations provide step count signals, and the step count signals are compared to the command pulses to detect a disparity. 
Northern Magnetics, Inc.
G G G
G05B G01D G01D
inventional inventional inventional
Martyn Walter E.
Lewis Hinds