Position sensing techniques

摘要

An apparatus includes a housing which defines a longitudinal axis; a positioning element which, relative to the housing, translates linearly along the longitudinal axis; and a rotational member which, relative to the housing, rotates about the longitudinal axis as the positioning element translates linearly along the longitudinal axis. The rotational member defines a helix to receive torque from the positioning element as the positioning element translates linearly along the longitudinal axis. The apparatus further includes a first sensor assembly to detect minor angular displacement of the rotational member (e.g., less than 360 degrees). The apparatus further includes a second sensor assembly to detect major angular displacement of the rotational member (e.g., a number of full 360 degree rotations). Such detection is capable of identifying a full angular displacement of the rotational member in response to linear translation of the positioning element from an initial position to a sensed position.

主权项

1. A position sensing apparatus, comprising:
a housing which defines a longitudinal axis; a positioning element which, relative to the housing, translates linearly along the longitudinal axis; a rotational member which, relative to the housing, rotates about the longitudinal axis as the positioning element translates linearly along the longitudinal axis, the rotational member defining a helix to receive torque from the positioning element as the positioning element translates linearly along the longitudinal axis; a first sensor assembly having (i) a set of magnets coupled to the rotational member and (ii) a first set of sensors coupled to the housing, the first set of sensors being constructed and arranged to detect angular displacement of the set of magnets about the longitudinal axis; and a second sensor assembly having (i) a linear displacement member, which relative to the housing, translates linearly along the longitudinal axis in response to movement of the positioning element and (ii) a second set of sensors coupled to the housing, the second set of sensors being constructed and arranged to detect linear displacement of the linear displacement member along the longitudinal axis.