WOLFRAM SYSTEM MODELER
WorldForceExternal force acting at frame_b, defined by 3 input signals and resolved in frame world, frame_b or frame_resolve |
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Diagram
Wolfram Language
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SystemModel["Modelica.Mechanics.MultiBody.Forces.WorldForce"]
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Information
This information is part of the Modelica Standard Library maintained by the Modelica Association.
The 3 signals of the force connector are interpreted as the x-, y- and z-coordinates of a force acting at the frame connector to which frame_b of this component is attached. Via parameter resolveInFrame it is defined, in which frame these coordinates shall be resolved:
| Types.ResolveInFrameB. | Meaning |
|---|---|
| world | Resolve input force in world frame (= default) |
| frame_b | Resolve input force in frame_b |
| frame_resolve | Resolve input force in frame_resolve (frame_resolve must be connected) |
If resolveInFrame = Types.ResolveInFrameB.frame_resolve, the force coordinates are with respect to the frame, that is connected to frame_resolve.
If force={100,0,0}, and for all parameters the default setting is used, then the interpretation is that a force of 100 N is acting along the positive x-axis of frame_b.
Note, the cut-torque in frame_b (frame_b.t) is always set to zero. Conceptually, a force and torque acts on the world frame in such a way that the force and torque balance between world.frame_b and frame_b is fulfilled. For efficiency reasons, this reaction torque is, however, not computed.
This force component is by default visualized as an arrow acting at the connector to which it is connected. The color of the arrow can be defined via variable color. The arrow points in the direction defined by the force signal. The length of the arrow is proportional to the length of the force vector using a global tool-dependent scaling factor.
An example how to use this model is given in the following figure:
This leads to the following animation
Parameters (2)
| animation |
Value: true Type: Boolean Description: = true, if animation shall be enabled |
|---|---|
| resolveInFrame |
Value: Modelica.Mechanics.MultiBody.Types.ResolveInFrameB.world Type: ResolveInFrameB Description: Frame in which input force is resolved (1: world, 2: frame_b, 3: frame_resolve) |
Inputs (2)
| color |
Default Value: Modelica.Mechanics.MultiBody.Types.Defaults.ForceColor Type: Color Description: Color of arrow |
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| specularCoefficient |
Default Value: world.defaultSpecularCoefficient Type: SpecularCoefficient Description: Reflection of ambient light (= 0: light is completely absorbed) |
Connectors (3)
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frame_b |
Type: Frame_b Description: Coordinate system fixed to the component with one cut-force and cut-torque |
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frame_resolve |
Type: Frame_resolve Description: The input signals are optionally resolved in this frame |
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force |
Type: RealInput[3] Description: x-, y-, z-coordinates of force resolved in frame defined by resolveInFrame |
Components (4)
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world |
Type: World Description: World coordinate system + gravity field + default animation definition |
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arrow |
Type: Arrow Description: Visualizing an arrow with variable size |
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basicWorldForce |
Type: BasicWorldForce Description: External force acting at frame_b, defined by 3 input signals |
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zeroPosition |
Type: ZeroPosition Description: Set absolute position vector of frame_resolve to a zero vector and the orientation object to a null rotation |
Used in Examples (1)
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Modelica.Mechanics.MultiBody.Examples.Elementary Rolling wheel set that is pulled by a force |