RelativeStates
Definition of relative state variables
Library
Modelica/Mechanics/Translational/Components
Description
Usually, the absolute position and the absolute velocity ofModelica.Mechanics.Translational.Inertia models are used as state variables.In some circumstances, relative quantities are better suited, e.g.,because it may be easier to supply initial values.In such cases, model RelativeStates allows the definition of state variablesin the following way:
- Connect an instance of this model between two flange connectors.
- The relative position and the relative velocity between the two connectors are used as state variables.
An example is given in the next figure
Here, the relative position and the relative velocity betweenthe two masses are used as state variables. Additionally, thesimulator selects either the absolute position and absolutevelocity of model mass1 or of model mass2 as state variables.
Parameters
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo_stateSelect | stateSelect | Priority to use the relative angle and relative speed 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 | |
mo_s_rel | s_rel | s_rel | Structure | |
mo_s_rel/fixed | fixed | Cell of scalars | true | |
mo_s_rel/start | start | Cell of scalars | ||
mo_v_rel | v_rel | v_rel | Structure | |
mo_v_rel/fixed | fixed | Cell of scalars | true | |
mo_v_rel/start | start | Cell of scalars | ||
mo_a_rel | a_rel | a_rel | Structure | |
mo_a_rel/fixed | fixed | Cell of scalars | true | |
mo_a_rel/start | start | Cell of scalars |
| 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 |
|---|---|---|---|---|
flange_a | implicit | (left) driving flange (flange axis directed into cut plane, e. g. from left to right) | input | 1 |
flange_b | implicit | (right) driven flange (flange axis directed out of cut plane) | output | 1 |