Single-Acting Actuator (G)

Single-acting linear actuator in the gas network.

single acting actuator g

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.

single acting actuator g 1

single acting actuator g 2

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 .

Block subcomponents

Block Single-Acting Actuator (G) consists of blocks:

The structure diagram of the actuator is shown in the schematic diagram.

single acting actuator g 2

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

port

# R — actuator piston
translational mechanics

Details

A mechanical progressive port corresponding to the actuator piston.

Program usage name

rod_flange

# H — heat port
heat

Details

A port related to the thermal conductivity of a gas.

Program usage name

thermal_port

# C — drive housing
translational mechanics

Details

Mechanical progressive port corresponding to the actuator housing.

Program usage name

case_flange

Output

# p — piston position
scalar

Details

Piston position in m.

Data types	`Float64`.
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	`Pressure at A causes positive displacement of R relative to C` \| `Pressure at A causes negative displacement of R relative to C`
Default value	`Pressure at A causes positive displacement of R relative to C`
Program usage name	`orientation`
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.

Units	`m^2` \| `cm^2` \| `ft^2` \| `in^2` \| `km^2` \| `mi^2` \| `mm^2` \| `um^2` \| `yd^2`
Default value	`0.01 m^2`
Program usage name	`piston_area`
Evaluatable	Yes

# Piston stroke — piston stroke
m | cm | ft | in | km | mi | mm | um | yd

Details

Maximum possible piston travel.

Units	`m` \| `cm` \| `ft` \| `in` \| `km` \| `mi` \| `mm` \| `um` \| `yd`
Default value	`0.1 m`
Program usage name	`stroke`
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.

Units	`l` \| `gal` \| `igal` \| `m^3` \| `cm^3` \| `ft^3` \| `in^3` \| `km^3` \| `mi^3` \| `mm^3` \| `um^3` \| `yd^3` \| `Nm/Pa` \| `Nm/bar` \| `lbfft/psi` \| `ftlbf/psi`
Default value	`1e-05 m^3`
Program usage name	`dead_volume`
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.

Units	`m^2` \| `cm^2` \| `ft^2` \| `in^2` \| `km^2` \| `mi^2` \| `mm^2` \| `um^2` \| `yd^2`
Default value	`0.01 m^2`
Program usage name	`port_area`
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	`Atmospheric pressure` \| `Specified pressure`
Default value	`Atmospheric pressure`
Program usage name	`pressure_type`
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.

Units	`Pa` \| `GPa` \| `MPa` \| `atm` \| `bar` \| `kPa` \| `ksi` \| `psi` \| `uPa` \| `kbar`
Default value	`0.101325 MPa`
Program usage name	`p_specified`
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	`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`
Default value	`Stiffness and damping applied smoothly through transition region, damped rebound`
Program usage name	`hardstop_model`
Evaluatable	No

# Hard stop stiffness coefficient — stiffness factor
N/m | lbf/ft | lbf/in

Details

Piston stiffness coefficient.

Units	`N/m` \| `lbf/ft` \| `lbf/in`
Default value	`1e10 N/m`
Program usage name	`k_hard_stop`
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.

Units	`kg/s` \| `N*s/m` \| `N/(m/s)` \| `lbf/(ft/s)` \| `lbf/(in/s)`
Default value	`150.0 N*s/m`
Program usage name	`C_hard_stop`
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'.

Units	`m` \| `cm` \| `ft` \| `in` \| `km` \| `mi` \| `mm` \| `um` \| `yd`
Default value	`0.1 mm`
Program usage name	`transition_region`
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.

Units	`m` \| `cm` \| `ft` \| `in` \| `km` \| `mi` \| `mm` \| `um` \| `yd`
Default value	`0.0 m`
Program usage name	`offset`
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.

Units	`Pa` \| `GPa` \| `MPa` \| `atm` \| `bar` \| `kPa` \| `ksi` \| `psi` \| `uPa` \| `kbar`
Default value	`0.101325 MPa`
Program usage name	`p_start`
Evaluatable	Yes

Details

Initial gas temperature in the actuator.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`293.15 K`
Program usage name	`T_start`
Evaluatable	Yes