Patent ID: 7060969

Claim:
A rotating machine comprising: a rotatable shaft; a sensing object member that is disk-shaped and is rotated integrally with the rotatable shaft; at least three rotation sensing devices, which are placed adjacent to the sensing object member and are arranged one after another at 90 degree intervals in a circumferential direction of the sensing object member, wherein each rotation sensing device generates an output signal, which corresponds to one of a rotational speed and a rotational angle of the sensing object member; and a control means for controlling one of a rotational speed and a rotational angle of the rotatable shaft based on a rotation measurement signal, which is obtained from the output signals of the at least three rotation sensing devices in such a manner that a two-periodic error component and a one-periodic error component are both eliminated from the rotation measurement signal, wherein: the control means computes a first correction signal based on the respective output signals of corresponding two of the at least three rotation sensing devices in such a manner that the two-periodic error component is eliminated from the first correction signal; the control means computes a second correction signal based on the respective output signals of corresponding two of the at least three rotation sensing devices in such a manner that the two-periodic error component is eliminated from the second correction signal; and the control means computes the rotation measurement signal based on the first correction signal and the second correction signal in such a manner that the one-periodic error component is eliminated from the rotation measurement signal.