Fixes #274 (Convenient and mighty initialization of frame kinematics)…

… by adding a new MultiBody.Joints.FreeMotionScalarInit joint where all scalar elements of the relative quantities can be initialized separately and also the StateSelect attribute can be set for every scalar element. Additionally, an example added as Examples.Elementary.DoublePendulumInitTip and two additional test models added in ModelicaTest. git-svn-id: https://svn.modelica.org/projects/Modelica/trunk@4033 7ce873d0-865f-4ce7-a662-4bb36ea78beb
modelica · Aug 5, 2010 · a408dbe · a408dbe
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diff --git a/Modelica/Images/MultiBody/Examples/Elementary/DoublePendulumInitTip.png b/Modelica/Images/MultiBody/Examples/Elementary/DoublePendulumInitTip.png
diff --git a/Modelica/Mechanics/MultiBody/Examples/Elementary/DoublePendulumInitTip.mo b/Modelica/Mechanics/MultiBody/Examples/Elementary/DoublePendulumInitTip.mo
@@ -0,0 +1,86 @@
+within Modelica.Mechanics.MultiBody.Examples.Elementary;
+model DoublePendulumInitTip
+  "Demonstrate how to initialize a double pendulum so that its tip starts at a predefined position"
+  extends Modelica.Icons.Example;
+
+  inner World world                              annotation (Placement(
+        transformation(extent={{-100,0},{-80,20}},rotation=0)));
+  Joints.Revolute revolute1(                             useAxisFlange=true) 
+                                                                 annotation (Placement(transformation(extent={{-60,0},
+            {-40,20}}, rotation=0)));
+  Rotational.Components.Damper damper(        d=0.1) 
+    annotation (Placement(transformation(extent={{-60,40},{-40,60}}, rotation=0)));
+  Parts.BodyBox boxBody1(                             r={0.5,0,0}, width=0.06) 
+    annotation (Placement(transformation(extent={{-22,0},{-2,20}}, rotation=0)));
+  Joints.Revolute revolute2                              annotation (Placement(transformation(extent={{20,0},{
+            40,20}}, rotation=0)));
+  Parts.BodyBox boxBody2(                             r={0.5,0,0}, width=0.06) 
+    annotation (Placement(transformation(extent={{62,0},{82,20}}, rotation=0)));
+  Modelica.Mechanics.MultiBody.Joints.FreeMotionScalarInit freeMotionScalarInit(
+    use_r=true,
+    r_rel_a_1(start=0.7, fixed=true),
+    r_rel_a_2(start=0.3, fixed=true),
+    use_v=true,
+    v_rel_a_1(fixed=true),
+    v_rel_a_2(fixed=true))
+    annotation (Placement(transformation(extent={{-20,-40},{0,-20}})));
+  annotation (Diagram(graphics),
+    experiment(StopTime=5),
+    experimentSetupOutput,
+    Documentation(info="<html>
+<p>
+This example demonstrates at hand of a double pendulum,
+how no-standard initialization can be defined:
+The absolute position of the pendulum tip, and its absolute speed
+shall be initially defined. This can be performed with the
+<a href=\"modelica://Modelica.Mechanics.MultiBody.Joints.FreeMotionScalarInit\">Joints.FreeMotionScalarInit</a>
+joint that allows to initialize individual elements of its relative vectors.
+In this case, the x-, and y-coordinates of the relative position vector 
+(visualized by the yellow arrow in the figure below) and of its
+derivative shall have a defined value at initial time.
+The configuration of the double pendulum at the initial time is
+shown below, where the tip position is required to have the coordinates
+x=0.7, y=0.3.
+</p>
+
+<blockquote>
+<img src=\"modelica://Modelica/Images/MultiBody/Examples/Elementary/DoublePendulumInitTip.png\">
+</blockquote>
+
+</html>"));
+equation
+  connect(damper.flange_b,revolute1. axis) annotation (Line(points={{-40,50},{
+          -36,50},{-36,28},{-50,28},{-50,20}}, color={0,0,0}));
+  connect(revolute1.support,damper. flange_a) annotation (Line(points={{-56,20},
+          {-56,28},{-70,28},{-70,50},{-60,50}}, color={0,0,0}));
+  connect(revolute1.frame_b,boxBody1. frame_a) 
+    annotation (Line(
+      points={{-40,10},{-22,10}},
+      color={95,95,95},
+      thickness=0.5));
+  connect(revolute2.frame_b,boxBody2. frame_a) 
+    annotation (Line(
+      points={{40,10},{62,10}},
+      color={95,95,95},
+      thickness=0.5));
+  connect(boxBody1.frame_b,revolute2. frame_a) 
+    annotation (Line(
+      points={{-2,10},{20,10}},
+      color={95,95,95},
+      thickness=0.5));
+  connect(world.frame_b,revolute1. frame_a) 
+    annotation (Line(
+      points={{-80,10},{-60,10}},
+      color={95,95,95},
+      thickness=0.5));
+  connect(world.frame_b, freeMotionScalarInit.frame_a) annotation (Line(
+      points={{-80,10},{-66,10},{-66,-30},{-20,-30}},
+      color={95,95,95},
+      thickness=0.5,
+      smooth=Smooth.None));
+  connect(freeMotionScalarInit.frame_b, boxBody2.frame_b) annotation (Line(
+      points={{0,-30},{88,-30},{88,10},{82,10}},
+      color={95,95,95},
+      thickness=0.5,
+      smooth=Smooth.None));
+end DoublePendulumInitTip;
diff --git a/Modelica/Mechanics/MultiBody/Examples/Elementary/package.order b/Modelica/Mechanics/MultiBody/Examples/Elementary/package.order
@@ -1,4 +1,5 @@
 DoublePendulum
+DoublePendulumInitTip
 ForceAndTorque
 FreeBody
 InitSpringConstant