DoubleActingCylinder

The Double Acting Cylinder model is a hydraulic actuator with two fluid ports (port_a and port_b)

Here a piston moves inside a cylinder when pressurized. The model includes parameters for piston and chamber geometry (areas, length), piston mass, initial position, end-stop stiffness and damping. It calculates piston motion according to fluid pressure differences at the ports, incorporates end-stop spring-damper forces when the piston hits the cylinder ends, and tracks changing chamber volumes and fluid masses as the piston moves. This model is typically used to simulate realistic hydraulic or pneumatic actuator behavior in dynamic system models.

Usage

HydraulicComponents.DoubleActingCylinder(L=1.5, M=0.1, area_a=908e-3, area_b=360e-3, lmin=0.001, s0=0.5, k_contact=1e8, d_contact=1e4)

Parameters:

Name	Description	Units	Default value
L	Length of the cylinder	m	1.5
M	Mass of the Piston	kg	0.1
area_a	Area of cross section of volume connected to 'port_a'	m2	0.908
area_b	Area of cross section of volume connected to 'port_b'	m2	0.36
s0	initial position of piston	m	0.5
k_contact	Contact stiffness N/m	N/m	100000000
d_contact	Contact damping N.s/m	N.s/m	10000

Connectors

• port_a - (Port)

• port_b - (Port)

• flange - This connector represents a mechanical flange with position and force as the potential and flow variables, respectively. (Flange)

Variables

Name	Description	Units
contact_force	Contact force from end stops	N
m_a	Mass of incoming fluid from port_a	kg
m_b	Mass of incoming fluid from port_b	kg
s	Position of center of mass	m
v	Velocity	m/s
F_dp		N
d_a	density at port a	kg/m3
d_b	density at port b	kg/m3
s_a		m
s_b		m

Behavior

Behavior of this component cannot be rendered because it includes path variables.

Source

"""
 The Double Acting Cylinder model is a hydraulic actuator with two fluid ports (port_a and port_b) 

 Here a piston moves inside a cylinder when pressurized. The 
 model includes parameters for piston and chamber geometry (areas, length), piston
 mass, initial position, end-stop stiffness and damping. It calculates piston motion
 according to fluid pressure differences at the ports, incorporates end-stop spring-damper
 forces when the piston hits the cylinder ends, and tracks changing chamber volumes and 
 fluid masses as the piston moves. This model is typically used to simulate realistic hydraulic 
 or pneumatic actuator behavior in dynamic system models.
"""
component DoubleActingCylinder
  port_a = Port() {
    "Dyad": {
      "placement": {
        "icon": {"iconName": "default", "x1": -50, "y1": 450, "x2": 50, "y2": 550, "rot": 0},
        "diagram": {"iconName": "default", "x1": -50, "y1": 450, "x2": 50, "y2": 550, "rot": 0}
      },
      "tags": []
    }
  }
  port_b = Port() {
    "Dyad": {
      "placement": {
        "icon": {"iconName": "default", "x1": 950, "y1": 450, "x2": 1050, "y2": 550, "rot": 0},
        "diagram": {"iconName": "default", "x1": 950, "y1": 450, "x2": 1050, "y2": 550, "rot": 0}
      },
      "tags": []
    }
  }
  flange = Flange() {
    "Dyad": {
      "placement": {
        "icon": {"iconName": "default", "x1": 450, "y1": 950, "x2": 550, "y2": 1050, "rot": 0},
        "diagram": {"iconName": "default", "x1": 460, "y1": 1000, "x2": 560, "y2": 1100, "rot": 0}
      },
      "tags": []
    }
  }
  "Length of the cylinder"
  parameter L::Length = 1.5
  "Mass of the Piston"
  parameter M::Mass = 0.1
  "Area of cross section of volume connected to 'port_a'"
  parameter area_a::Area = 908e-3
  "Area of cross section of volume connected to 'port_b'"
  parameter area_b::Area = 360e-3
  final parameter lmin::Length = 0.001
  "initial position of piston"
  parameter s0::Position = 0.5
  "Contact stiffness [N/m] (typical for steel)"
  parameter k_contact::TranslationalSpringConstant = 1e8
  "Contact damping [N.s/m] (energy dissipation)"
  parameter d_contact::TranslationalDampingConstant = 1e4
  "Contact force from end stops"
  variable contact_force::Force
  "Mass of incoming fluid from `port_a`"
  variable m_a::Mass
  "Mass of incoming fluid from `port_b`"
  variable m_b::Mass
  "Position of center of mass"
  variable s::Position
  "Velocity"
  variable v::Velocity(guess = 0)
  variable F_dp::Dyad.Force
  "density at port a"
  variable d_a::Density
  "density at port b"
  variable d_b::Density
  variable s_a::Position
  variable s_b::Position
relations
  initial s = s0
  F_dp = area_a * port_a.p - area_b * port_b.p
  d_a = density(port_a.medium, port_a.p)
  d_b = density(port_b.medium, port_b.p)
  s_a = s + lmin
  s_b = L - s + lmin
  m_a = d_a * area_a * s_a
  m_b = d_b * area_b * s_b
  port_a.m_flow = der(m_a)
  port_b.m_flow = der(m_b)
  flange.s = s
  v = der(s)
  contact_force = ifelse(s <= lmin, k_contact * (lmin - s) - d_contact * v, ifelse(s > L, k_contact * (L - s) - d_contact * v, 0))
  "contact_force = if s<lmin then k_contact*(lmin-s)-d_contact*v else if s>L then k_contact*(L-s)-d_contact*v else 0"
  M * der(v) = F_dp + flange.f + contact_force
metadata {
  "Dyad": {
    "experiments": {},
    "tests": {},
    "labels": [
      {
        "label": "$(instance)",
        "x": 500,
        "y": 1100,
        "rot": 0,
        "layer": "icon",
        "attrs": {}
      }
    ],
    "icons": {"default": "dyad://Dyad/Default.svg"},
    "path": {},
    "doc": {"behavior": true}
  }
}
end

Flattened Source

"""
 The Double Acting Cylinder model is a hydraulic actuator with two fluid ports (port_a and port_b) 

 Here a piston moves inside a cylinder when pressurized. The 
 model includes parameters for piston and chamber geometry (areas, length), piston
 mass, initial position, end-stop stiffness and damping. It calculates piston motion
 according to fluid pressure differences at the ports, incorporates end-stop spring-damper
 forces when the piston hits the cylinder ends, and tracks changing chamber volumes and 
 fluid masses as the piston moves. This model is typically used to simulate realistic hydraulic 
 or pneumatic actuator behavior in dynamic system models.
"""
component DoubleActingCylinder
  port_a = Port() {
    "Dyad": {
      "placement": {
        "icon": {"iconName": "default", "x1": -50, "y1": 450, "x2": 50, "y2": 550, "rot": 0},
        "diagram": {"iconName": "default", "x1": -50, "y1": 450, "x2": 50, "y2": 550, "rot": 0}
      },
      "tags": []
    }
  }
  port_b = Port() {
    "Dyad": {
      "placement": {
        "icon": {"iconName": "default", "x1": 950, "y1": 450, "x2": 1050, "y2": 550, "rot": 0},
        "diagram": {"iconName": "default", "x1": 950, "y1": 450, "x2": 1050, "y2": 550, "rot": 0}
      },
      "tags": []
    }
  }
  flange = Flange() {
    "Dyad": {
      "placement": {
        "icon": {"iconName": "default", "x1": 450, "y1": 950, "x2": 550, "y2": 1050, "rot": 0},
        "diagram": {"iconName": "default", "x1": 460, "y1": 1000, "x2": 560, "y2": 1100, "rot": 0}
      },
      "tags": []
    }
  }
  "Length of the cylinder"
  parameter L::Length = 1.5
  "Mass of the Piston"
  parameter M::Mass = 0.1
  "Area of cross section of volume connected to 'port_a'"
  parameter area_a::Area = 908e-3
  "Area of cross section of volume connected to 'port_b'"
  parameter area_b::Area = 360e-3
  final parameter lmin::Length = 0.001
  "initial position of piston"
  parameter s0::Position = 0.5
  "Contact stiffness [N/m] (typical for steel)"
  parameter k_contact::TranslationalSpringConstant = 1e8
  "Contact damping [N.s/m] (energy dissipation)"
  parameter d_contact::TranslationalDampingConstant = 1e4
  "Contact force from end stops"
  variable contact_force::Force
  "Mass of incoming fluid from `port_a`"
  variable m_a::Mass
  "Mass of incoming fluid from `port_b`"
  variable m_b::Mass
  "Position of center of mass"
  variable s::Position
  "Velocity"
  variable v::Velocity(guess = 0)
  variable F_dp::Dyad.Force
  "density at port a"
  variable d_a::Density
  "density at port b"
  variable d_b::Density
  variable s_a::Position
  variable s_b::Position
relations
  initial s = s0
  F_dp = area_a * port_a.p - area_b * port_b.p
  d_a = density(port_a.medium, port_a.p)
  d_b = density(port_b.medium, port_b.p)
  s_a = s + lmin
  s_b = L - s + lmin
  m_a = d_a * area_a * s_a
  m_b = d_b * area_b * s_b
  port_a.m_flow = der(m_a)
  port_b.m_flow = der(m_b)
  flange.s = s
  v = der(s)
  contact_force = ifelse(s <= lmin, k_contact * (lmin - s) - d_contact * v, ifelse(s > L, k_contact * (L - s) - d_contact * v, 0))
  "contact_force = if s<lmin then k_contact*(lmin-s)-d_contact*v else if s>L then k_contact*(L-s)-d_contact*v else 0"
  M * der(v) = F_dp + flange.f + contact_force
metadata {
  "Dyad": {
    "experiments": {},
    "tests": {},
    "labels": [
      {
        "label": "$(instance)",
        "x": 500,
        "y": 1100,
        "rot": 0,
        "layer": "icon",
        "attrs": {}
      }
    ],
    "icons": {"default": "dyad://Dyad/Default.svg"},
    "path": {},
    "doc": {"behavior": true}
  }
}
end

Test Cases

No test cases defined.

Related

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