Changeset 903

Timestamp:

12/09/07 09:14:19 (12 months ago)

Author:

otter

Message:

Bug in MultiBody.Parts.Rotor1D corrected, that leads in some situations
to wrong reaction torques (movement should not be influenced by this bug)

Location:

Modelica/branches/maintenance/2.2.2/Modelica

Files:

• Mechanics/MultiBody/parts.mo (modified) (1 diff)
• package.mo (modified) (1 diff)

Modelica/branches/maintenance/2.2.2/Modelica/Mechanics/MultiBody/parts.mo

@@ -1974 +1974 @@
       "(right) driven flange (flange axis directed OUT OF cut plane)" 
       annotation (extent=[90, -10; 110, 10]);
+    
+    /* Reaction torque:
+        t = n*(J*a - flange_a.tau - flange_b.tau) + cross(w_a, nJ*w)
+ 
+     Since
+        J*a = flange_a.tau + flange_b.tau - nJ*der(w_a);
+ 
+     the reaction torque can be simplified to
+        t = n*(- nJ*der(w_a)) + cross(w_a, nJ*w)
+ 
+  */
     Modelica.Mechanics.MultiBody.Interfaces.Frame_a frame_a(
         r_0=r_0,
         R=R,
         f=zeros(3),
-        t=nJ*a + cross(w_a, nJ*w)) if world.driveTrainMechanics3D 
+        t=cross(w_a, nJ*w)-e*(nJ*der(w_a))) if   world.driveTrainMechanics3D 
       "Frame in which rotor housing is fixed (connector is removed, if world.driveTrainMechanics3D=false)"
       annotation (extent=[-20, -120; 20, -80], rotation=90);

Modelica/branches/maintenance/2.2.2/Modelica/package.mo

@@ -594 +594 @@
   <tr><td valign=\"top\"> Model-Name </td>
       <td valign=\"top\"> Description text</td> 
+  </tr>
+  <tr><td colspan=\"2\"><b>Mechanics.MultiBody.Parts</b></td></tr>
+  <tr><td valign=\"top\"> Rotor1D </td>
+      <td valign=\"top\"> The 3D reaction torque was not completely correct and gave in 
+                        some situations a wrong result. This bug should not influence the
+                        movement of a multi-body system, but only the constraint torques
+                        are sometimes not correct. </td> 
   </tr>
   <tr><td colspan=\"2\"><b>Mechanics.Rotational.</b></td></tr>