A vibration waveform output by a gyro sensor set in a main pump is received. The vibration waveform is subjected to a frequency analysis and a frequency spectrum is calculated. A feature value is calculated from the frequency spectrum. Life expiration of the main pump is determined using the feature value. When the feature value is represented as R, a sum of squares of amplitudes in the frequency spectrum is represented as D, and a sum of squares of the amplitudes exceeding a first determination value is represented as P, R=√(P/D).
机译：接收由设置在主泵中的陀螺仪传感器输出的振动波形。对振动波形进行频率分析并计算频谱。根据频谱计算特征值。使用功能值确定主泵的使用寿命。当特征值被表示为R时，频谱中的振幅的平方和被表示为D，并且超过第一确定值的振幅的平方和被表示为P，R ＝＆radic;（P / D ）。