Optimization of Performance Characteristics of Electropneumatic (Two-Stage) Servo Valve

Abstract

Servo valve is the key element in electropneumatic servomechanism. In this study, an electropneumatic two-stage servo valves were investigated in order to improve their static and dynamic characteristics. These servo valves consist of a pilot stage and a power stage. The paper discusses three different pilot stages: the jet pipe pilot stage, the supply (side) flapper nozzle pilot stage and the exhaust (side) flapper nozzle pilot stage. The static and dynamic characteristics of the devices were investigated analytically and by computer simulation. For the three pilot stage types it was found that the optimal value of the static and dynamic characteristics could be obtained if the ratio between the effective areas of the supply channel and exhaust port of the pilot stage has a definite value (depending on the pilot stage type).