MarkerNodePosition

A node-Marker attached to a position-based node. It can be used for connectors, joints or loads where position is required. If connectors also require orientation information, use a MarkerNodeRigid.

Additional information for MarkerNodePosition:

• This Marker has/provides the following types = Node, Position

The item MarkerNodePosition with type = ‘NodePosition’ has the following parameters:

• name [type = String, default = ‘’]:

  marker’s unique name
• nodeNumber [type = NodeIndex, default = invalid (-1)]:

  node number to which marker is attached to
• visualization [type = VMarkerNodePosition]:

  parameters for visualization of item

The item VMarkerNodePosition has the following parameters:

• show [type = Bool, default = True]:

  set true, if item is shown in visualization and false if it is not shown

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DESCRIPTION of MarkerNodePosition

The node position marker provides an interface to a node which contains a position (NodePoint, NodePoint2D, NodeRigidBodyEP, NodePointSlope, …) and accesses position, velocity and the position jacobian. The position and velocity are computed according to the definition of output variables in the respective nodes.

The position jacobian represents the derivative of the node position \({\mathbf{p}}_\mathrm{n}\) with all nodal coordinates,

\[\LU{0}{{\mathbf{J}}_\mathrm{pos}} = \frac{\partial \LU{0}{{\mathbf{p}}_\mathrm{n}}}{\partial {\mathbf{q}}_\mathrm{n}}\]

For details, see the respective definition of the node and the C++ implementation.

In examplary case of a NodeRigidBody2D, see Section NodeRigidBody2D, its coordinates are \({\mathbf{q}}_\mathrm{n}=[q_0,\;q_1,\;\psi_0,\;]\tp\), where \(q_0\) represents the \(x\)-displacement and \(q_1\) represents the \(y\)-displacement, such that the jacobian for the 3D position vector reads

\[\LU{0}{{\mathbf{J}}_\mathrm{pos}^{\mathrm{NodeRigidBody2D}}} = \mr{1}{0}{0} {0}{1}{0} {0}{0}{0}\]

Relevant Examples and TestModels with weblink:

ALEANCFpipe.py (Examples/), ANCFcantileverTest.py (Examples/), ANCFcantileverTestDyn.py (Examples/), ANCFcontactCircle.py (Examples/), ANCFcontactCircle2.py (Examples/), ANCFslidingJoint2D.py (Examples/), ANCFslidingJoint2Drigid.py (Examples/), ANCFtestHalfcircle.py (Examples/), ANCFtests2.py (Examples/), bungeeJump.py (Examples/), doublePendulum2D.py (Examples/), flexibleRotor3Dtest.py (Examples/), ACFtest.py (TestModels/), ANCFcontactCircleTest.py (TestModels/), ANCFcontactFrictionTest.py (TestModels/)

The web version may not be complete. For details, consider also the Exudyn PDF documentation : theDoc.pdf