Device for determining the absolute angular position of a turning component

A device (10) for determination of absolute angular position (θa) of a turning component (3, 4) in relation to a fixed structure (5) by means of a sensor (16) of relative angular position (θr), comprising:

• a rotating mobile circular multipole magnetic ring (11), designed to be integral with a turning component (3, 4), with the multipole ring (11) being capable of making, jointly with the turning component (3, 4), several turns around its axis of rotation (R) from an angular position called the reference position, said ring (11) comprising a main channel (14) and a reference channel (15) called the “turn cue” channel, the main channel (14) and the “turn cue” channel (15) being concentric on the magnetic ring (11);
• a fixed magnetic sensor (16), arranged opposite and away from multipole ring (11) by an air gap, and consisting of at least three sensing elements (17, 18, 19) at least two (17, 18) of which are positioned opposite the main channel (14) so as to produce two periodic electric signals (A, B) in quadrature and at least one (19) positioned opposite the reference channel (15) so as to produce a reference electrical signal (C) called the “turn cue” signal in the form of an electric pulse per turn of the multipole ring (11), with this pulse corresponding to an angular position called the “turn cue” angular position of the turning component (3, 4) in relation to the fixed structure (5), with the angular displacement between said reference angular position and said “turn cue” angular position being called “offset” (θoffset);
• counting means (20) for counting pulses derived from signals (A, B) capable of enabling the determination of relative angular position (θr) of the multipole ring (11) and variations of this relative angular position (θr);
• and
• a treatment device (26) comprising:
• detection means (27) for detecting an angular position (θ0) of the multipole ring (11) near said reference angular position;
• resetting means (28) for resetting the absolute angular position (θa) of the multipole ring (11), driven by detection means (27) capable of assigning, during detection of a pulse of the “turn cue” signal (C), the offset value (θoffset) to the value of the absolute angular position (θa) of the multipole ring (11) in relation to its reference angular position;
• and
• determination means (29) for determining the absolute angular position (θa) of the ring (11) on all of the turns made by the turning component (3, 4) ascertained from the offset value (θoffset) and variations in the relative angular position (θr).