Error on simple four link mechanism simulation with modelica
<p>I'm trying to implement a 4 link mechanism and the model I've put together is shown here:</p>

<pre>
         <img src="https://i.stack.imgur.com/3wSqG.png" width="500">               
</pre>

<p>Revolute1 has a speed of 5 rad/s. All bars are 0.05 m in diameter. World settings are the default and you can see the bar vectors on the picture. Nothing else is changed.</p>

<p>When I try to run the simulation I get these errors on OpenModelica:</p>

<blockquote>
  <p>[1] 10:29:43 Symbolic Error
  [Modelica.Mechanics.MultiBody.Parts: 238:5-238:62]: Model is structurally singular, error found sorting equations</p>
  
  <p>[2] 10:33:25 Translation Error
  Internal error Transformation Module PFPlusExt index Reduction Method Pantelides failed!</p>
</blockquote>

<p>What am I doing wrong? It seems pretty straight-forward. Thanks.</p>