MULTITURN ABSOLUTE ROTARY POSITION SENSOR WITH COARSE DETECTOR FOR AXIAL MOVEMENT AND INDUCTIVE FINE DETECTOR FOR ROTARY MOVEMENT

摘要

There is described a rotary position sensor for sensing the rotational movement of a shaft about an axis in which a follower is coupled to the shaft and moves over an associated range of linear movement in concert with rotation of the shaft about the axis, wherein each position within the range of rotary movement of the shaft corresponds to a single position within the range of linear movement of the follower. A first detector outputs a signal which is representative of a plurality of rotary positions of the shaft about the axis, and a second detector detects the linear position of the follower within the range of movement of the follower. A position calculator determines the position of the shaft within the range of rotary movement of the shaft using the positions detected by the first and second detectors. The first detector comprises a planar transmit aerial and a planer receive aerial having an electromagnetic coupling which varies in dependence upon the relative rotary position of the shaft and the mounting.