AN ANALYSIS OF AN ELECTROHYDRAULIC CLOSED-LOOP SERVOMECHANISM.
JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
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An investigation was made to analyze the functioning of a closed-loop electrohydraulic servomechanism by varying the frequency of the sinusoidal input signal, and studying the phase lag of the output signal and the amplitude ratio of output to input signal. The gain of the closed-loop system was maintained constant while the time constant of the servo amplifier was adjusted to several selected values. For each time constant selected for the servo amplifier, the closed-loop system was maintained constant while the time constant of the servo amplifier was adjusted to several selected values. For each time constant selected for the servo amplifier, the closed-loop system response curves of phase lag and the ratio of the amplitude of output to input were obtained. The phase lag and amplitude ratio of the servo system is predicted more accurately by the theoretical results for the third-order system, than those of the second-order system. The theoretical third-order closed-loop system may be used to predict characteristic results over a frequency range up to approximately ten cycles per second, when engineering accuracy is required. This is particularly true with regard to the phase-lag characteristics. The order of the closed-loop system is greater than the third, as indicated by the phase lag and output signal attenuation being greater than that theoretically predicted for a third-order system.
- Hydraulic and Pneumatic Equipment