| 摘要 |
PURPOSE:To decide whether or not foreign matter is mixed in the rotary body automatically by integrating the waveform of vibration that the rotary body generates periodically, and processing the integrated value statistically and comparing it with a normal distribution. CONSTITUTION:A stepping motor 1 is supported by a vibration detection sensor 2, whose output waveform is converted by a waveform processing circuit 3 into an integrated waveform is each constant period. Then a statistical computation processor 4 finds the statistical distribution of the integrated value and considers that an abnormal sound is generated suddenly by the foreign matter in the output waveform of the sensor 2 if an extremely different integrated value is found, thereby judging that the foreign matter is mixed in the article. Namely, when a noise due to the abnormal sound is generated as shown in a figure (b), it is put together with the periodic waveform of driving pulses and the integrated value of one cycle becomes relatively large like a 3rd waveform in a figure (e). Then the integrated value of one cycle is processed statistically to obtain a normal distribution shown in a figure (f), but if the noise component due to the abnormal sound is generated, an integrated value which is not in the distribution is generated. Therefore, it is judged that the vibration waveform includes the abnormal sound. |
