Multiposition actuator in an isothermal liquid system
Simscape / Fluids / Valve Actuators
Simscape / Fluids / Isothermal Liquid / Valves & Orifices / Valve Actuators & Forces / Valve Actuators
The Multiposition Valve Actuator block models a multiposition actuator in an isothermal liquid system. It can be used in combination with the 2-Way Directional Valve (IL), 3-Way Directional Valve (IL), or 4-Way Directional Valve (IL) blocks. The actuator position is influenced by the input signal and switching time, and not by loading.
Actuation begins when the signal at port A exceeds 50% of the Nominal signal value. After the time period set by the Switching-on time parameter, the actuator begins to move toward the Push-pin stroke limit. When the input signal at port A falls below 50% of the Nominal signal value, the actuator reverses its direction after the time period set by the Switching-off time parameter. The motion can be interrupted mid-stroke.
Actuator position
In the image above, tde is the Switching-on time, which is equal to the time periods tae and tve. In region tae, the actuator moves at constant acceleration with parabolic displacement. In region tve, the actuator moves linearly, with constant velocity, toward full push-pin extension. The actuator switches direction when the control signal is off:
tdr is a transitional no-displacement time period set by the Switching-off time.
tar is a period of acceleration with parabolic displacement.
tvr is period of linear displacement toward the actuator Initial position.
When Actuator positions is set to
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.
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
.
2-Way Directional Valve (IL) | 3-Way Directional Valve (IL) | 4-Way Directional Valve (IL) | Cartridge Valve Actuator (IL) | Pilot Valve Actuator (IL) | Proportional Valve Actuator