Hydraulic remote position-controllers

Brief descriptions arc given of the significant characteristics of the more important hydraulic devices used in remote position-controllers. Such devices include valves, dashpots, pumps, approximately constantpressure sources and hydraulic motors. Combinations of these primary devices are then described which, for analytical purposes, may be regarded as single ¿elements¿ in the control sequence of any servo-mechanism of which they form a part. Amongst these combinations are pump- and valve-controlled power drives, various types of hydraulic relays and passive mechanical networks incorporating dashpots. The practical applications of these hydraulic servoelements are then illustrated by means of mathematical analyses in which are deduced the conditions for stability and performance to be expected of typical hydraulic remote position-control systems.