Method of diagnosing abnormality of reduction gear and apparatus for carry out the method

摘要

An apparatus for carry out a method of diagnosing abnormality of a reduction gear, the reduction gear including an intermediate shaft element disposed between an input shaft and an output shaft and rotating in proportion to a rotation of the input shaft to transmit the rotation to the output shaft, the apparatus has: a disturbance observer that obtains an estimated disturbance value regarding the reduction gear, based on a torque instruction and a velocity feedback-value acquired when a pair of driven members which rotate relative to each other with a motor as a driving source are in relative rotation at a constant velocity; a specific spectral component specifying portion for extracting a specific spectral component corresponding to a constant multiple of a rotational frequency of the intermediate shaft element from a frequency components of the estimated disturbance value obtained by frequency analysis; and a diagnosing portion, which compares an amplitude of the specific spectral component specified by the specific spectral component specifying portion with a threshold value, and diagnoses an abnormality in a case where the amplitude of the specific spectral component exceeds the threshold value, or a normality in a case where the amplitude of the specific spectral component is equal to or less than the threshold value.