電磁弁直接駆動空気圧レギュレータのリップル低減

抄録

Regarding electrical power sources, the switching regulator is widely used because the efficiency exceeds that of other types such as the regulator using an analog circuit. A pneumatic pressure servo system directly operated by switching valves is expected to have a higher efficient and compact pressure regulator, instead of the diaphragm type pressure regulator, though there is a ripple in the output pressure fundamentally. The ripple is not improved sufficiently because when the operating threshold level of switching valves is set to its extreme to reduce the ripple, unexpected switching occurs caused by noise which is included in the output pressure.
In this report, the mechanism of the appearance of the unexpected switching action is analyzed, and as a result, it is shown that the principal cause of this problem is the resonance occurring in the pressure vessel and the detected pressure crosses the threshold level incorrectly having a detrimental influence on the resonance. The frequency of resonance can be supposed easily and it is convenient in designing a noise filter to its reduction. From this viewpoint, the digital FIR or IIR filter is introduced to overcome this problem and the effect on the reduction of ripple and the performance are determined by the use of experiments. Furthermore, the proper design of the filter for this system is discussed and shown.