Example for http://stackoverflow.com/a/38767267/610990

Planar4Bar.mo

within ;
model Planar4Bar "Planar4Bar.mo"
  inner Modelica.Mechanics.MultiBody.World world(
    animateWorld=false,
    animateGravity=false) annotation(Placement(transformation(extent={{-105,-45},{-85,-25}})));
  Modelica.Mechanics.MultiBody.Joints.Revolute revolute1(
    phi(fixed=true),
    w(start=5,fixed=true)) annotation(Placement(transformation(extent={{-55,-30},{-35,-10}})));
  Modelica.Mechanics.MultiBody.Joints.Revolute revolute2 annotation(Placement(transformation(extent={{25,-30},{45,-10}})));
  Modelica.Mechanics.MultiBody.Joints.Revolute revolute3 annotation(Placement(transformation(extent={{-55,20},{-35,40}})));
  Modelica.Mechanics.MultiBody.Joints.RevolutePlanarLoopConstraint revolute4 annotation(Placement(transformation(extent={{25,20},{45,40}})));
  Modelica.Mechanics.MultiBody.Parts.BodyCylinder bodyCylinder1(
    r={0,2,0},
    diameter=0.05) annotation(Placement(transformation(
    origin={-80,10},
    extent={{-10,-10},{10,10}},
    rotation=90)));
  Modelica.Mechanics.MultiBody.Parts.BodyCylinder bodyCylinder2(
    r={-5,0,0},
    diameter=0.05,
    r_0(each fixed=true)) annotation(Placement(transformation(extent={{-15,-30},{5,-10}})));
  Modelica.Mechanics.MultiBody.Parts.BodyCylinder bodyCylinder3(
    r={4,1,0},
    diameter=0.05) annotation(Placement(transformation(extent={{-15,20},{5,40}})));
  Modelica.Mechanics.MultiBody.Parts.BodyCylinder bodyCylinder4(
    r={1,-3,0},
    diameter=0.05) annotation(Placement(transformation(
    origin={60,10},
    extent={{-10,-10},{10,10}},
    rotation=-90)));
  equation
    connect(bodyCylinder1.frame_b,revolute3.frame_a) annotation(Line(
      points={{-80,20},{-80,25},{-80,30},{-60,30},{-55,30}},
      color={95,95,95}));
    connect(revolute3.frame_b,bodyCylinder3.frame_a) annotation(Line(
      points={{-35,30},{-30,30},{-20,30},{-15,30}},
      color={95,95,95}));
    connect(bodyCylinder2.frame_b,revolute2.frame_a) annotation(Line(
      points={{5,-20},{10,-20},{20,-20},{25,-20}},
      color={95,95,95}));
    connect(bodyCylinder4.frame_b,revolute2.frame_b) annotation(Line(
      points={{60,0},{60,-5},{60,-20},{50,-20},{45,-20}},
      color={95,95,95}));
    connect(bodyCylinder3.frame_b,revolute4.frame_a) annotation(Line(
      points={{5,30},{10,30},{20,30},{25,30}},
      color={95,95,95}));
    connect(revolute4.frame_b,bodyCylinder4.frame_a) annotation(Line(
      points={{45,30},{50,30},{60,30},{60,25},{60,20}},
      color={95,95,95}));
    connect(bodyCylinder1.frame_a,revolute1.frame_b) annotation(Line(
      points={{-80,0},{-80,-5},{-30,-5},{-30,-20},{-35,-20}},
      color={95,95,95}));
    connect(revolute1.frame_a,world.frame_b) annotation(Line(
      points={{-55,-20},{-60,-20},{-80,-20},{-80,-35},{-85,-35}},
      color={95,95,95}));
    connect(world.frame_b,bodyCylinder2.frame_a) annotation(Line(
      points={{-85,-35},{-80,-35},{-20,-35},{-20,-20},{-15,-20}},
      color={95,95,95}));
  annotation(uses(Modelica(version="3.2.1")));
end Planar4Bar;

I suggest adding:

• experiment(StopTime = 8) to annotation()
• extends Modelica.Icons.Example;