WOLFRAM SYSTEM MODELER
    DoublePendulumSimple double pendulum with two revolute joints and two bodies  | 
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SystemModel["PlanarMechanics.Examples.DoublePendulum"]

Beware this is a chaotic system. However, the chaotic part should start after 10s.
Selected continuous time states
| body | 
         Type: Body Description: Body component with mass and inertia  | 
    |
|---|---|---|
| fixedTranslation | 
         Type: FixedTranslation Description: A fixed translation between two components (rigid rod)  | 
    |
| fixed | 
         Type: Fixed Description: Frame fixed in the planar world frame at a given position and orientation  | 
    |
| body1 | 
         Type: Body Description: Body component with mass and inertia  | 
    |
| fixedTranslation1 | 
         Type: FixedTranslation Description: A fixed translation between two components (rigid rod)  | 
    |
| planarWorld | 
         Type: PlanarWorld Description: Planar world coordinate system + gravity field + default animation definition  | 
    |
| revolute | 
         Type: Revolute Description: A revolute joint  | 
    |
| revolute1 | 
         Type: Revolute Description: A revolute joint  | 
    
Developed 2010 at the DLR Institute of System Dynamics and Control