Update med7.xacro

Author: Khouloud-Hamrouni

lbr_description/urdf/med7/med7.xacro

@@ -14,6 +14,11 @@
 
     <!-- KDL requires a link without inertia -->
     <link name="$(arg robot_name)_floating_link" />
+    <link name="world" />
+    <joint name="$world_to_base" type="fixed">
+        <parent link="world" />
+        <child link="$(arg robot_name)_floating_link" />
+    </joint>
 
     <!--joint
         between <robot_name>_floating_link and robot_name_link_0-->
@@ -27,4 +32,4 @@
         robot_name="$(arg robot_name)"
         mode="$(arg mode)"
         system_config_path="$(arg system_config_path)" />
-</robot>
+</robot>