Drag
====


**Actuator allowing to simulate the drag force**


This actuator allows to simulate the drag force, or fluid
resistance. It is not controlable, as it depends only of robot
parameters, and environment.

The drag force is generally written as:

Fd = 0.5 * rho * vel_sq * A * Cd

where
    - rho is the density of the fluid (env dependant)
    - A is the cross sectional area (robot dependent)
    - Cd  is the drag coefficient,  related to the object shape and
      the Reynolds Number

All these values are aggregated into the property DragCoeff, to ease
the configuration of the component.


.. cssclass:: properties morse-section

Configuration parameters for Drag
---------------------------------


You can set these properties in your scripts with ``<component>.properties(<property1>=..., <property2>=...)``.

- ``DragCoeffX`` (floatAn aggregated value to scale the drag force on X robot axis, default: ``0.09``)
	(no documentation available yet)
- ``DragCoeffY`` (floatAn aggregated value to scale the drag force on Y robot axis, default: ``0.09``)
	(no documentation available yet)
- ``DragCoeffZ`` (floatAn aggregated value to scale the drag force on Z robot axis, default: ``0.5``)
	(no documentation available yet)


.. cssclass:: fields morse-section

Data fields
-----------

No data field documented (see above for possible notes).

.. cssclass:: services morse-section

Services for Drag
-----------------

- ``get_properties()`` (blocking)
    Returns the properties of a component.
    
    
  - Return value

    a dictionary of the current component's properties  

- ``set_property(prop_name, prop_val)`` (blocking)
    Modify one property on a component
    
    
  - Parameters

    - ``prop_name``: the name of the property to modify (as shown the documentation)
    - ``prop_val``: the new value of the property. Note that there is no checking about the type of the value so be careful

  - Return value

    nothing 

- ``get_configurations()`` (blocking)
    Returns the configurations of a component (parsed from the properties).
    
    
  - Return value

    a dictionary of the current component's configurations  



.. cssclass:: examples morse-section

Examples
--------


The following examples show how to use this component in a *Builder* script:

.. code-block:: python


    from morse.builder import *
    
    # adds a default robot (the MORSE mascott!)
    robot = Morsy()
    
    # creates a new instance of the actuator
    drag = Drag()

    # place your component at the correct location
    drag.translate(<x>, <y>, <z>)
    drag.rotate(<rx>, <ry>, <rz>)
    
    robot.append(drag)
    
    # define one or several communication interface, like 'socket'
    drag.add_interface(<interface>)

    env = Environment('empty')
    

.. cssclass:: files morse-section

Other sources of examples
+++++++++++++++++++++++++

- `Source code <../../_modules/morse/actuators/drag.html>`_
- `Unit-test <../../_modules/base/drag_testing.html>`_




*(This page has been auto-generated from MORSE module morse.actuators.drag.)*