| 摘要 |
PROBLEM TO BE SOLVED: To accurately determine rotating conditions such as the angle of rotation and a rotating speed. SOLUTION: A permanent magnet 37 constituting an encoder 35 is polarized (arranged) in such a way that the south pole and the north pole are equally divided into two by a virtual plane which passes the center of the permanent magnet 37. A pair of sensors 42a and 42b are provided in such a way as to be 90°out of phase with each other with respect to the circumferential direction of the encoder 35. A tangentθis determined from the ratio äsinθ/cosθ} of a sineθ(sine wave) to a cosineθ(cosine wave) acquired from the output of each sensor. By determining an angleθfrom the tangentθ, it is possible to freely detect the rotating conditions such as the angle of rotation and the rotating speed with output errors based on temperature changes corrected. COPYRIGHT: (C)2004,JPO
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