Single-Acting Actuator (G)
Single-acting linear actuator in the gas network.
Description
Block Single-Acting Actuator (G) simulates a linear actuator whose piston is controlled by a gas chamber. The actuator creates a reciprocating motion of the piston, the force on which is determined by the overpressure of the gas chamber.
The figure shows the main components of the actuator for different values of the Mechanical orientation parameters. Port A represents the entrance to the gas chamber. Port R is associated with the piston and port C is associated with the actuator housing. Port H provides the thermal interaction between the gas chamber and the environment.
Relocation
The piston movement is determined by the displacement of port R relative to port C. The direction of piston movement is set by the Mechanical orientation parameters. Piston movement is neutral (equal to 0
) when the chamber volume is equal to Dead volume.
Hard stop model
Piston movement is limited by a pair of hard stops located within the piston stroke. The block uses the same hard stop model as the Translational Hard Stop block and accounts for damping and stiffness factors at both ends of the piston stroke.
If piston travel is positive, the lower hard stop is at , and the upper hard stop is at . If the piston travel is negative, the lower hard stop is at and the upper hard stop is at .
Ports
Conserving
#
A
—
gas inlet or outlet
gas
Details
The port corresponding to the gas inlet or outlet of the gas chamber.
Program usage name |
|
#
R
—
actuator piston
translational mechanics
Details
A mechanical progressive port corresponding to the actuator piston.
Program usage name |
|
#
H
—
heat port
heat
Details
A port related to the thermal conductivity of a gas.
Program usage name |
|
#
C
—
drive housing
translational mechanics
Details
Mechanical progressive port corresponding to the actuator housing.
Program usage name |
|
Output
#
p
—
piston position
scalar
Details
Piston position in m.
Data types |
|
Complex numbers support |
No |
Parameters
Actuator
#
Mechanical orientation —
piston travel direction
Pressure at A causes positive displacement of R relative to C
| Pressure at A causes negative displacement of R relative to C
Details
Determines the direction of piston displacement. Options for selection:
-
`Pressure at A causes positive displacement of R relative to C' - piston displacement is positive if the volume of gas in port A increases. This corresponds to the movement of the rod out of the cylinder.
-
Pressure at A causes negative displacement of R relative to C
- piston movement is negative if the volume of gas in port A increases. This corresponds to movement of the rod into the cylinder.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
No |
#
Piston cross-sectional area —
cross-sectional area of the piston rod
m^2
| cm^2
| ft^2
| in^2
| km^2
| mi^2
| mm^2
| um^2
| yd^2
Details
Cross-sectional area of the piston rod.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |
#
Piston stroke —
piston stroke
m
| cm
| ft
| in
| km
| mi
| mm
| um
| yd
Details
Maximum possible piston travel.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |
#
Dead volume —
volume of gas in the chamber, at which the piston movement is equal to 0
l
| gal
| igal
| m^3
| cm^3
| ft^3
| in^3
| km^3
| mi^3
| mm^3
| um^3
| yd^3
| N*m/Pa
| N*m/bar
| lbf*ft/psi
| ft*lbf/psi
Details
Gas volume at piston movement value 0
. This gas volume corresponds to the position of the piston at the top of the actuator end cap.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |
#
Cross-sectional area at port A —
cross-sectional area of the port A
m^2
| cm^2
| ft^2
| in^2
| km^2
| mi^2
| mm^2
| um^2
| yd^2
Details
Cross-sectional area of the port A.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |
#
Environment pressure specification —
method of setting the ambient pressure
Atmospheric pressure
| Specified pressure
Details
Method of setting the ambient pressure. The Atmospheric pressure
option sets the ambient pressure to 0.101325 MPa
.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
No |
#
Environment pressure —
ambient pressure
Pa
| GPa
| MPa
| atm
| bar
| kPa
| ksi
| psi
| uPa
| kbar
Details
User-defined ambient pressure.
Dependencies
To use this parameter, set Environment pressure specification to Specified pressure
.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |
Hard Stop
#
Hard stop model —
selecting the model of the hard stop
Stiffness and damping applied smoothly through transition region, damped rebound
| Full stiffness and damping applied at bounds, undamped rebound
| Full stiffness and damping applied at bounds, damped rebound
Details
Model selection for the force acting on the piston when it is at the end positions. For more information, see the block Translational Hard Stop.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
No |
#
Hard stop stiffness coefficient —
stiffness factor
N/m
| lbf/ft
| lbf/in
Details
Piston stiffness coefficient.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |
#
Hard stop damping coefficient —
damping factor
kg/s
| N*s/m
| N/(m/s)
| lbf/(ft/s)
| lbf/(in/s)
Details
Piston damping factor.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |
#
Transition region —
range of action of the rigid stop model
m
| cm
| ft
| in
| km
| mi
| mm
| um
| yd
Details
The operating range of the hard stop model. Outside this range, the Hard stop model does not apply to the extreme piston positions and no additional force is applied to the piston by the stop.
Dependencies
To use this parameter, set the Hard stop model to `Stiffness and damping applied smoothly through transition region, damped rebound'.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |
Initial Conditions
#
Initial piston displacement —
initial piston position
m
| cm
| ft
| in
| km
| mi
| mm
| um
| yd
Details
Piston position at the beginning of the simulation.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |
#
Initial gas pressure —
initial gas pressure
Pa
| GPa
| MPa
| atm
| bar
| kPa
| ksi
| psi
| uPa
| kbar
Details
Initial gas pressure in the actuator.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |
#
Initial gas temperature —
initial gas temperature
K
| degC
| degF
| degR
| deltaK
| deltadegC
| deltadegF
| deltadegR
Details
Initial gas temperature in the actuator.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |