| 摘要 |
A rotary encoder is provided for measuring absolute rotation around an axis 112 of the rotary encoder. The rotary encoder comprises a magnetised element 100 comprising first and second surfaces at an angle to one another; a first magnetic track 102 provided on the first surface and a second magnetic track 104 provided on the second surface, wherein the first and second magnetic tracks subtend an angle θ around the axis of the rotary encoder, and wherein each magnetic track comprises a number of magnetic pole pairs, a magnetic pole pair being formed of two poles defining regions of opposite magnetic polarization. The numbers of magnetic pole pairs in each track are different and have a greatest common factor of one. Also included are first and second magnetic sensor arrangements 106, 108, the first magnetic sensor arrangement arranged to detect a magnetic field of the first magnetic track and the second magnetic sensor arrangement arranged to detect a magnetic field of the second magnetic track, wherein the magnetic sensor arrangements are rotatably coupled to the magnetised element around the axis of the rotary encoder. |
