| 摘要 |
PURPOSE:To obtain the stable driving gear of high efficiency, by using AC voltage sweeping periodically from a driving-frequency-higher section to a section lower in driving frequency. CONSTITUTION:By the one side detection output of a mechanical arm current detecting circuit 8, through a peak holder 9, the amplitude value of mechanical arm current is detected, and the input to a micro-computer 1 from an A/D converter 10 is provided. Then, the mechanical arm current is detected, and the value Im of the current and the value Imo of the mechanical arm current driving frequency just before the value Im are compared with each other. When the Im is greater than the Imo, then a specified frequency value is subtracted from the driving frequency, and when the Im is less than the Imo, then specified frequency is added to the driving frequency. In other words, frequency is changed and swept from its higher section to its lower section till the mechanical arm current is reduced: when the driving frequency comes to resonance frequency and the mechanical arm current is suddenly reduced, then the frequency is swept from its higher section to its lower section in the same manner after the specified frequency is added to, and so as a result, a device is driven by the only frequency approximate to the resonance frequency, and high efficiency is obtained. |
