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Multiposition Valve Actuator

Multiposition actuator in any fluid domain

  • Multiposition Valve Actuator block

Libraries:
Simscape / Fluids / Valve Actuators
Simscape / Fluids / Isothermal Liquid / Valves & Orifices / Valve Actuators & Forces / Valve Actuators

Description

The Multiposition Valve Actuator block models a multiposition actuator in any fluid domain. You can use it in combination with any valve block that takes a physical signal as input. The input signal and the switching time affect the actuator position.

Two-Position Actuator Movement

Actuation begins when the value of the signal at port A exceeds 50% of the value of the Nominal signal value parameter. After a time period that equals one third of the value of the Switching-on time parameter, the actuator begins to move toward the limit specified by the Push-pin stroke parameter.

When the value of the signal at port A falls below 50% of the value of the Nominal signal value parameter, the actuator reverses its direction after a time period that equals one third of the value of the Switching-off time parameter. The motion can be interrupted mid-stroke.

In the image above, ton is the value of the Switching-on time parameter. The actuator motion during ton contains an initial rest, a quadratic motion, and a linear motion, represented by tde, tae, and tve, respectively. tde, tae, and tve are all equal length.

The actuator switches direction when the control signal is off. toff is the value of the Switching-off time parameter, during which the actuator repeats the same stages as the switching-on motion. tdr is a stage of rest, tar is a stage of quadratic motion, and tvr is a stage of linear motion. At the end of toff, the actuator position is at the value of the Initial position parameter. tdr, tar, and tvr are all equal length.

When Actuator positions is 2, the Actuator travel direction parameter sets the direction of the push-pin motion.

The actuator motion can be interrupted at any time. If the push-pin motion is disrupted mid-stroke, the switch-on and switch-off times are adjusted proportionally to the push-pin position, relative to the push-pin stroke.

Three-Position Actuator Movement

When Actuator positions is set to 3, the signal at port A moves the actuator in a positive direction and the signal received at port B moves the actuator in a negative direction. Only one signal, from one port, is processed at a time. To switch control between ports A and B, or between positive and negative displacement control, the actuator must first move to a neutral position. If the push-pin motion is disrupted mid-stroke, the switch-on and switch-off times are adjusted proportionally to the push-pin position, relative to the push-pin stroke. The actuator motion can be interrupted at any time.

When controlled by the signal at port A, the three-position actuator has the same displacement profile as the two-position actuator when Actuator travel direction is set to Positive. When controlled by the signal at port B, it has the same profile as the two-position actuator when Actuator travel direction is set to Negative.

Examples

Ports

Input

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Input port, specified as a physical signal.

When Actuator positions is set to 2, this port can either control negative or positive actuator movement, according to the Actuator travel direction setting.

When Actuator positions is set to 3, this port receives a physical signal that corresponds to a positive actuator displacement direction.

Input port for negative actuator displacement, received as a physical signal.

Dependencies

To enable this port, set Actuator positions to 3.

Output

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Actuator position, in m, specified as a physical signal.

If you use the Multiposition Valve Actuator block with a valve from the Gas Library, the gas block converts the actuator signal units of m to units of 1.

Parameters

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Number of valve position signals. When set to 2, the actuator receives one signal and sets one position signal. When set to 3, the actuator receives a positive and a negative signal and sets one position signal.

Maximum push-pin extension.

Time period to reach the value of the Push-pin stroke parameter. The period begins after the input signal rises above 50% of the value of the Nominal signal value parameter.

Time period to return to the Initial position parameter from the Push-pin stroke parameter. The period begins after the input signal falls below 50% of the Nominal signal value.

Nominal signal for fully extended actuator. The actuator motion is triggered when the input signal reaches 50% of the Nominal signal value.

Starting position of the actuator. Retracted and Extended correspond to the actuator push-pin stroke limits.

When Actuator positions is set to 2, the Initial position default is Retracted. When Actuator positions is set to 3, the Initial position default is Neutral. Neutral corresponds to the middle of the Push-pin stroke.

Direction of the actuator motion in response to the physical signal input. The Positive setting corresponds to push-pin extension.

Dependencies

To enable this parameter, set Actuator positions to 2.

Extended Capabilities

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C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2020a