SimHydraulics^®

Proportional and Servo-Valve Actuator

Simulate continuous valve driver with output proportional to input signal

Library

Valve Actuators

Description

The Proportional and Servo-Valve Actuator block represents an electromagnetic actuator that is used in proportional and servo-valves to drive a spool or other working member. The block is intended to work with one of the directional valve models to form a desirable configuration of a proportional or servo-valve. The block is implemented as a data-sheet-based model and reproduces only the input/output relationship, or the actuator's transient response, as presented in the catalog or data sheet.

The Proportional and Servo-Valve Actuator block is built using the blocks from the Physical Signals library. Both the input and the output of the block are physical signals. The block diagram of the model is shown in the following figure.

The model consists of the first-order lag, PS Integrator, PS Saturation block, and the PS Subtract block that closes the feedback. The configuration is found to be suitable to simulate behavior of servo-valves and high-quality proportional valves.

The typical transient responses of a servo-valve or a high-quality proportional valve are shown in the following figure. The only difference between the two responses in the figure is the value of the saturation. The response that corresponds to 100% of the input signal is considerable slower than that with the 20% saturation.

You can adjust the block parameters, such as saturation, gain, and time constant, to make the transient responses close enough to those provided in the data sheet. The most effective way to adjust the parameters is to use the Optimization Toolbox™ software.

Dialog Box and Parameters

Gain: Gain of the first-order lag. The default value is 377.
Time constant: Time constant of the first-order lag. The default value is 0.002 s.
Saturation: Saturation level of the Saturation block in the actuator model. The default value is 0.3.

Ports

The block has one physical signal input port and one physical signal output port.

Examples