ROTATION ANGLE DETECTION APPARATUS HAVING FUNCTION OF DETECTING ENTRY OF FOREIGN SUBSTANCE BASED ON FREQUENCY CHARACTERISTIC OF SIGNALS

摘要

A rotation angle detection apparatus includes a rotator having a track unit to detect the rotation angle of a rotation axis; a detection unit disposed in correspondence with the track unit; a rotation angle calculation unit for calculating the rotation angle of the rotation axis based on signals generated by the detection unit; a rotation speed calculation unit for calculating the rotation speed of the rotation axis; and an abnormality detection unit for detecting an abnormality. The abnormality detection unit includes a frequency analyzing unit for calculating the frequency characteristic of the signals; a storage unit for storing the number of the signals per revolution of the rotator; a signal frequency calculation unit for calculating a signal frequency; and a determination unit for detecting the abnormality in the detection apparatus, when the frequency characteristic includes a component of a higher order than the signal frequency.

主权项

1. A rotation angle detection apparatus comprising:
a rotator having a track unit to detect the rotation angle of a rotation axis; a detection unit disposed in correspondence with the track unit; a rotation angle calculation unit for calculating the rotation angle of the rotation axis based on signals generated by the detection unit; a rotation speed calculation unit for calculating the rotation speed of the rotation axis based on the signals; and an abnormality detection unit for detecting an abnormality based on the signals, wherein the abnormality detection unit includes: a frequency analyzing unit for calculating the frequency characteristic of the signals; a storage unit for storing the number of the signals generated from the track unit per revolution of the rotator; a signal frequency calculation unit for calculating a signal frequency that is the product of the number of the signals stored in the storage unit and the rotation speed calculated by the rotation speed calculation unit; and a determination unit for detecting the abnormality, when the frequency characteristic includes a component of a higher order than the signal frequency.