| 摘要 |
<P>PROBLEM TO BE SOLVED: To always secure a control amount as desired and precision as desired even to a change and a difference of a control condition. <P>SOLUTION: A dither condition processing part 7 detecting a dither amount (amplitude) in positive/negative periods of a dither waveform from a deviation of a target current and an actual current and improving amplitude of the dither waveform in the positive period or negative period until the dither amounts (amplitude) in the positive/negative periods of the dither waveform match is arranged in a dithering means overlapping the dither waveform generated in a dither waveform generating part 6 with a target current flowing in an electromagnetic coil 5 of a proportional valve. The control amount as desired is obtained. The deviation of the target current and actual current is temporarily stored as a last dither amount. The amplitude of the dither waveform is increased/decreased so that the dither amount of this time matches the dither amount. The dither amounts are made equal in the positive/negative periods and an average value of the target current is held as it is and precision as desired is obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT |
