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A Hybrid Digital Hydraulic Servo
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 01, 1965 by SAE International in United States
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In many applications, control system equations are being processed in a digital computer. Digital-to-analog (D/A) converters are then used to make command signals compatible with analog final control elements. It is more desirable to design a highly integrated system which uses a digital servo and does not require D/A conversion. However, digital hydraulic servo valves have not yet been highly developed, and some types are quite complex.
It was the object of this program to design a hydraulic digital servo which uses the standard, proven two-stage electrohydraulic servo valve. This was done by having the servo valve itself perform the function of a D/A converter. It accepts digital signals in computer format and quantizes actuator velocity. Initial design studies were performed, followed by analog and digital computer studies. A breadboard unit was built and evaluated. Two main conclusions have thus far been reached:
Performance comparable to analog servo systems can be obtained with the hybrid.
The basic concept provides inherent redundancy, thus high reliability; the hybrid servo operates at reduced performance with most single failures.
Experimental as well as analytical data are presented in the paper.
CitationYount, E. and Stiglic, P., "A Hybrid Digital Hydraulic Servo," SAE Technical Paper 650317, 1965, https://doi.org/10.4271/650317.
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