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Gearmotor
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*Introduced in MORe v4.2*

Represents a geared motor. Models rotor and gear inertia including gear reduction.

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Block diagram
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   .. image:: media/gearmotor.png
      :alt: Gear motor block diagram
      :scale: 50 %

==============  ==============================================================
Signal          Description
==============  ==============================================================
:math:`u_f`     Filter output
:math:`u_v`     Coupling link velocity
:math:`u_x`     Coupling link position
:math:`v_{fb}`  Motor velocity. Can be used as feedback in architecture.
:math:`x_{fb}`  Motor position. Can be used as feedback in architecture.
:math:`y`       Motor output. Force acting on coupling link.
==============  ==============================================================

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Parameter
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==============  ====================  =================  ==============================================================
Variable        Units linear          Units rotary       Description
==============  ====================  =================  ==============================================================
Gear ratio      :math:`-`             :math:`-`          Gear ratio
Stiffness       :math:`N/m`           :math:`Nm/rad`     Stiffness of gear at the output shaft [#f1]_
Damping         :math:`N s/m`         :math:`Nm s/rad`   Damping of gear
Inertia         :math:`kg`            :math:`kg m^2`     Gear and motor inertia [#f2]_
==============  ====================  =================  ==============================================================

.. [#f1] Torsional stiffness, usually referred as :math:`C_{t21}` in datasheets. Calculated as quotient of applied to
   torque to the output shaft and its resulting twist. (The input shaft is fixed) :math:`C_{t21} = \Delta T / \Delta\phi`

.. [#f2] Total inertia as sum of rotor inertia and gear inertia observed from the drive side.


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Coupling
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Link selection to represent the motor. The controller output (force/torque) will be applied to the selected link.