Description fixes (#200)

* Renamed bumper mesh link to "bumper", added dummy bumper zone for "bump_front_center.

* Added static transform publishers for left and right wheel drop links.

* Added /tf_static remapping to allow namespacing

* Added use_sim_time paramter to joint_state_publisher
Removed static transforms for wheeldrops

irobot_create_common/irobot_create_common_bringup/launch/robot_description.launch.py

@@ -46,6 +46,7 @@ def generate_launch_description():
         executable='joint_state_publisher',
         name='joint_state_publisher',
         output='screen',
+        parameters=[{'use_sim_time': True}],
     )
 
     # Define LaunchDescription variable

irobot_create_common/irobot_create_description/urdf/bumper.urdf.xacro

@@ -15,7 +15,7 @@ functional, while the 4 remaining ones are created as dummy links. -->
   <link name="${link_name}"/>
 </xacro:macro>
 
-<xacro:macro name="bumper" params="name:=bump_front_center parent_link:=base_link update_rate:=62.0 gazebo visual_mesh collision_mesh
+<xacro:macro name="bumper" params="name:=bumper parent_link:=base_link update_rate:=62.0 gazebo visual_mesh collision_mesh
   *origin *inertial">
   <xacro:property name="link_name" value="${name}"/>
   <xacro:property name="joint_name" value="${name}_joint"/>
@@ -67,6 +67,11 @@ functional, while the 4 remaining ones are created as dummy links. -->
     <preserveFixedJoint>true</preserveFixedJoint>
   </gazebo>
 
+  <xacro:dummy_bumper_zone
+      name="bump_front_center">
+      <origin xyz="0.175 0 0.039" rpy="0 0 0"/>
+  </xacro:dummy_bumper_zone>
+
   <xacro:dummy_bumper_zone
       name="bump_front_left">
       <origin xyz="0.02345 -0.0875 0.025" rpy="0 0 0.5235985"/>