Torpedo Anchor

A torpedo anchor.

Collaboration diagram for Torpedo Anchor:

Simulation of a 6DOF torpedo anchor. Implementation in class TorpedoAnchor.

Author

Jorgen Haavind Jensen

Example configuration excerpt

<Lib
  LibName="fhsim_base"
  SimObject="TorpedoAnchor"
  Name="Anc"
  MaterialRho="1000"
  ShankLength="1"
  ShankDiameter="0.02"
  ShankThickness="0.01"
  FlukeSideLength="0.5"
  FlukePointLength="0.6"
  FlukeWidth="0.02"
  FlukeThickness="0.1"
  ShankFlukeAngle="1"
/>
...
<Connection
  Anc.Force="0,0,-13.8729"
/>
...
<InitialCondition
  Anc.Position="0,0,-500"
  Anc.Velocity="0,0,0"
  Anc.Theta="1.0,0.0,0.0,0.0"
  Anc.Omega="0.0,0.0,0.0"
/>

Note

The simulation must include an Environment, e.g. CDefaultEnvironment.

Input Ports

Name	Width	Description
Force	3	Force vector in Newton.

Output Ports

Name	Width	Description
Position	3	Anchor position in meter.
Velocity	3	Anchor velocity in meter per second.
Theta	4	Anchor orientation as Quarternion.
Omega	3	Anchor angular velocity in rad per second.

Configuration parameters

Name	Width	Description
MaterialRho	1	Material density in kg per meter cubed.
ShankLength	1	Shank length [m].
ShankDiameter	1	Shank diameter [m].
ShankThickness	1	Shank thickness [m].
FlukeSideLength	1	Fluke side length [m].
FlukePointLength	1	Fluke point length [m].
FlukeWidth	1	Fluke width [m].
FlukeThickness	1	Fluke thickness [m].
ShankFlukeAngle	1	Shank-Fluke angle [rad].

Initial conditions

Name	Width	Description
Position	3	Initial position in 3D. North, East, Down in meter.
Velocity	3	Initial velocity in meter per second.
Theta	4	Initial orientation in quaternion.
Omega	3	Initial angular velocity in rad per second.

Full example file

<Contents>
  <OBJECTS>
    <Lib
        LibName          = "base"
        SimObject        = "TorpedoAnchor"
        Name             = "Anc"
        MaterialRho      = "1000"
        ShankLength      = "1"
        ShankDiameter    = "0.1"
        ShankThickness   = "0.05"
        FlukeSideLength  = "2.5"
        FlukePointLength = "3"
        FlukeWidth       = "0.1"
        FlukeThickness   = "0.5"
     />
 
     <Lib
        LibName         ="base"
        SimObject       = "DefaultEnvironment"
        Name            = "Env"
        Seadepth        = "500"
        Density         = "1000"
        CurrentVelocity = "0,0,0"
    />
 
    <Lib
        LibName     = "base"
        SimObject   = "Cable"
        Name        = "C"
        cableLength = "10"
        numElements = "50"
        diameter    = "0.01"
        cableWeight = "100"
    />
 
  </OBJECTS>
  
  <INTERCONNECTIONS>
    <Connection
        Anc.Force          = "0,0,0"
        C.PositionA        = "0,0,0"
        C.PositionB        = "Anc.Position"
        C.VelocityA        = "0,0,0"
        C.VelocityB        = "Anc.Velocity"
        C.RetractedLengthA = "0"
        C.RetractedLengthB = "0"
        C.RetractedSpeedA  = "0"
        C.RetractedSpeedB  = "0"
    />
  </INTERCONNECTIONS>
 
  <INITIALIZATION>
    <InitialCondition
        Anc.Position = "0,0,-10"
        Anc.Velocity = "0,0,0"
        Anc.Theta    = "1,0,0,0"
        Anc.Omega    = "0,0,0"
    />
  </INITIALIZATION>
 
  <INTEGRATION>
    <Engine
        IntegratorMethod           = "2"
        NumCores                   = ""
        TOutput                    = "0, 0:1:10, 10"
        LogStates                  = "0"
        Stepsize                   = "0"
        HMax                       = "0.01"
        HMin                       = "1E-060"
        AbsTol                     = "0.001"
        RelTol                     = "0.001"
        UseRSSNormInsteadOfInfNorm = "0"
        FinalStatesFile            = ""
        InitialStatesFile          = ""
        FileOutput                 = "objects:all"
    />
  </INTEGRATION>
</Contents>

This SimObject is referred to as TorpedoAnchor