added sanity check for framedposeition changeFrame with empty frame

source/RobotAPI/libraries/core/FramedPose.cpp

@@ -74,8 +74,10 @@ namespace armarx
 
     void FramedDirection::changeFrame(const VirtualRobot::RobotPtr& robot, const string& newFrame)
     {
-        if(frame == "")
+        if (frame == "")
+        {
             frame == GlobalFrame;
+        }
 
 
         if (getFrame() == newFrame)
@@ -513,6 +515,13 @@ namespace armarx
             return;
         }
 
+        if (newFrame.empty())
+        {
+            ARMARX_WARNING_S << "Frame Conversion: Frame is empty, always set frame names! ...assuming GlobalFrame";
+            changeToGlobal(referenceRobot);
+            return;
+        }
+
         Eigen::Matrix4f oldFrameTransformation = Eigen::Matrix4f::Identity();
 
         if (!referenceRobot->hasRobotNode(newFrame))