From e7d45ddbb5d3ce82a57a109cece01138ae4ca5fe Mon Sep 17 00:00:00 2001
From: Roger Cheng <roger.random@outlook.com>
Date: Thu, 4 Oct 2018 17:52:30 -0700
Subject: [PATCH] Fix problems exposed trying to use URDF in RViz * Neato laser
 needs to be moved up to compensate for   base_link moving down to ground
 level. * Neato laser needs to rotate 180 degrees to match   sensor mount
 location * A sphere was added to correspond to caster wheel. * Drive wheels
 are "fixed" for now, at least until we can   publish wheel angles.

---
 urdf/phoebe.urdf.xacro | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/urdf/phoebe.urdf.xacro b/urdf/phoebe.urdf.xacro
index b09a210..eb29c80 100644
--- a/urdf/phoebe.urdf.xacro
+++ b/urdf/phoebe.urdf.xacro
@@ -56,7 +56,7 @@
   <joint name="base_neato_joint" type="fixed">
     <parent link="base_link"/>
     <child link="neato_laser"/>
-    <origin xyz="${neato_offset_x} ${neato_offset_y} ${neato_offset_z}"/>
+    <origin xyz="${neato_offset_x} ${neato_offset_y} ${neato_offset_z + wheel_diameter/2}" rpy="0 0 ${pi}" />
   </joint>
 
   <xacro:macro name="wheel" params="side reflect">
@@ -69,7 +69,7 @@
         <material name="wheel" />
       </visual>
     </link>
-    <joint name="base_wheel_${side}_joint" type="continuous">
+    <joint name="base_wheel_${side}_joint" type="fixed"> <!-- TODO: type="continuous" when we read encoder data and publish wheel angle -->
       <axis xyz="0 1 0" rpy="0 0 0" />
       <parent link="base_link" />
       <child link="wheel_${side}" />
@@ -79,4 +79,20 @@
 
   <xacro:wheel side="left" reflect="1" />  
   <xacro:wheel side="right" reflect="-1" />
+
+  <link name="wheel_caster">
+    <visual>
+      <geometry>
+        <sphere radius="${wheel_diameter/2}" />
+      </geometry>
+      <material name="wheel" />
+    </visual>
+  </link>
+
+  <joint name="base_caster" type="fixed">
+    <parent link="base_link" />
+    <child link="wheel_caster" />
+    <origin xyz="${-body_center_to_cylinder-body_width/2+wheel_diameter/2} 0 ${wheel_diameter/2}" />
+  </joint>
+
 </robot>