PointMass
Rigid body where body rotation and inertia tensor is neglected (6 potential states)
Library
Modelica/Mechanics/MultiBody/Parts
Description
Rigid body where the inertia tensor is neglected.This body issolely defined by its mass.By default, this component is visualized by a sphere that hasits center at frame_a. Note, thatthe animation may be switched off via parameter animation = false.
Every PointMass has potential states. If possible a tool will selectthe states of joints and not the states of PointMass because this isusually the most efficient choice. In this case the position andvelocity of frame_a of the body will be computedby the component that is connected to frame_a. However, if a PointMass is movingfreely in space, variables of the PointMass have to be used as states. The potentialstates are: The position vector frame_a.r_0 from the origin of theworld frame to the origin of frame_a of the body, resolved inthe world frame and the absolute velocity v_0 of the origin offrame_a, resolved in the world frame (= der(frame_a.r_0)).
Whether or not variables of the body are used as states is usuallyautomatically selected by the Modelica translator. If parameterenforceStates is set to true in the "Advanced" menu,then PointMass variables frame_a.r_0 and der(frame_a.r_0)are forced to be used as states.
Parameters
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo_animation | animation | = true, if animation shall be enabled (show sphere) | Scalar | true |
mo_m | m | Mass of mass point | Scalar | |
mo_r_0 | r_0 | r_0 | Structure | |
mo_r_0/fixed | fixed | Cell of vectors of size 3 | true | |
mo_r_0/start | start | Cell of vectors of size 3 | ||
mo_v_0 | v_0 | v_0 | Structure | |
mo_v_0/fixed | fixed | Cell of vectors of size 3 | true | |
mo_v_0/start | start | Cell of vectors of size 3 | ||
mo_a_0 | a_0 | a_0 | Structure | |
mo_a_0/fixed | fixed | Cell of vectors of size 3 | true | |
mo_a_0/start | start | Cell of vectors of size 3 |
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo_sphereDiameter | sphereDiameter | Diameter of sphere | Scalar | |
mo_sphereColor | sphereColor | Color of sphere | Vector of size 3 | |
mo_specularCoefficient | specularCoefficient | Reflection of ambient light (= 0: light is completely absorbed) | Scalar |
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo_stateSelect | stateSelect | Priority to use frame_a.r_0, v_0 (= der(frame_a.r_0)) as states | Structure | |
mo_stateSelect/choice1 | StateSelect.never | Number | 0 | |
mo_stateSelect/choice2 | StateSelect.avoid | Number | 0 | |
mo_stateSelect/choice3 | StateSelect.default | Number | 0 | |
mo_stateSelect/choice4 | StateSelect.prefer | Number | 0 | |
mo_stateSelect/choice5 | StateSelect.always | Number | 0 |
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo__nmodifiers | Number of Modifiers | Specifies the number of modifiers | Number | |
mo__modifiers | Modifiers | Add new modifier | Structure | |
mo__modifiers/varname | Variable name | Cell of strings | ||
mo__modifiers/attribute | Attribute | Cell of strings | 'start' | |
mo__modifiers/value | Value |
Ports
| Name | Type | Description | IO Type | Number |
|---|---|---|---|---|
frame_a | implicit | Coordinate system fixed at center of mass point | input | 1 |