US 9,810,552 B2
Inductive position sensing in linear actuators
Ian W. Hunter, Lincoln, MA (US); George C. Whitfield, Winchester, MA (US); and Peter G. Madden, Burlington, MA (US)
Assigned to Nucleus Scientific Inc., Cambridge, MA (US)
Filed by Nucleus Scientific Inc., Cambridge, MA (US)
Filed on Apr. 16, 2015, as Appl. No. 14/688,052.
Claims priority of provisional application 61/981,934, filed on Apr. 21, 2014.
Prior Publication US 2015/0300843 A1, Oct. 22, 2015
Int. Cl. G01B 7/14 (2006.01); G01D 5/20 (2006.01); G01B 7/12 (2006.01); G01B 7/00 (2006.01); G01D 5/14 (2006.01)
CPC G01D 5/20 (2013.01) [G01B 7/003 (2013.01); G01B 7/125 (2013.01); G01D 5/14 (2013.01); G01D 5/2006 (2013.01); G01D 5/2033 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method comprising:
applying drive signals to drive coils of an array of drive coils arranged adjacent to each other and wound around a magnetically permeable core and coaxially aligned with an axis of the core to thereby cause a magnet assembly arranged on the array of drive coils to move along the array of drive coils and parallel to the axis of the core;
measuring an impedance of each drive coil of a plurality of drive coils within the array of drive coils; and
from information derived from the measured impedances of the plurality of drive coils, determining the position of the magnet assembly relative to the array of drive coils.