Dynamic Properties of Single-Spool and Two-Spool Two-Stage Servovalves 901621
A mathematical model of a dynamically stable flapper-nozzle pilot valve has been used in conjunction with the second stage of a flow control valve that comprises a single spool. The model has been used to calculate the valve gain and the dynamic response of the component parts. Real-time and frequency response results have been compared with those when using a two-spool version of the same type, each of the two spools being identical to the spool used in the single-spool version. It is shown that the dynamic response is improved significantly when the single-spool replaces the two-spool version.