Controlled Actuator $—$ Actuator of a three-position directional control valve with first-order spool dynamics

The Controlled Actuator component describes the spool position of a directional control valve that has two coils. This model can be used if the controller is modeled in such a way that it uses one real output signal with the following spool positions:

 • 0 means the middle position of the spool
 • -1 and +1 mean the valve is completely open

The commanded opening of the valve is input at $u$. The position of the spool ($\mathrm{spoolPos}$) is modeled as a first-order system.

When $u<-0.95$, then $\mathrm{spoolPos}=-1$.

When $0.95, then $\mathrm{spoolPos}=1$.

Otherwise, $\mathrm{spoolPos}=0$.

Intermediate positions are also modeled.

The movement of the spool is described by a first-order system. This is appropriate for valves that are directly actuated by a spool. The time to shift from the neutral position to an end position (${\mathrm{\tau }}_{\mathrm{opening}}$) may be different than the time to shift to the neutral position (${\mathrm{\tau }}_{\mathrm{closing}}$).

Connections

 Name Description Modelica ID $\mathrm{spoolPos}$ spoolPos $u$ u

Parameters

 Name Default Units Description Modelica ID ${\mathrm{\tau }}_{\mathrm{opening}}$ $0.03$ $s$ Switching time to open valve 95 % tau_opening ${\mathrm{\tau }}_{\mathrm{closing}}$ $0.02$ $s$ Switching time to close valve 95 % tau_closing