Publishing joint_state with python and displaying in rviz

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Hey Guys,

I'm have a robot arm I'm trying to put into ros. I went through the urdf_tutorial and got a urdf that works with the tutorial launch file. Now, I want to write a node that publishes to /joint_states and uses robot_state_publisher to update the robot. I'd like to display the robot in rviz, and also write a subscriber to /joint_states that moves the actual arm.

The problem I'm having is, when I write my own simple node to publish to /joint_states, rviz gives me errors for all of my joint transforms. (ie "no transform from [first_segment] to [base_link]" and "no transform from [second_segment] to [base_link]", also there's "Fixed Frame: No tf data. Actual error: Fixed Frame [base_link] does not exist"

I've looked at the documentation for robot_state_publisher, read the code for joint_state_publisher and tried manually sending tf's through my node.

I use this command to put in my urdf and launch the code:

roslaunch launch/display.launch model:=urdf/josh-arm.urdf

Here's my urdf, launch file, and python code (sorry I couldn't attach it.. don't have enough karma):

Thanks!

<launch>

  <arg name="model" />
  <arg name="gui" default="true" />
  <arg name="rvizconfig" default="$(find urdf_tutorial)/rviz/urdf.rviz" />

  <param name="robot_description" command="$(find xacro)/xacro.py $(arg model)" />
  <param name="use_gui" value="$(arg gui)"/>

  <node name="updateArm" pkg="me439arm" type="updateArm.py"/>
  <node name="robot_state_publisher" pkg="robot_state_publisher" type="state_publisher" />
  <node name="rviz" pkg="rviz" type="rviz" args="-d $(arg rvizconfig)" required="true" />

</launch>

The urdf file:

<?xml version="1.0"?>
<robot name="visual">

<material name="blue">
    <color rgba="0 0 0.8 1"/>
  </material>
  <material name="black">
    <color rgba="0 0 0 1"/>
  </material>
  <material name="white">
    <color rgba="1 1 1 1"/>
  </material>

  <link name="base_link">
    <visual>
      <geometry>
        <cylinder length="0.1026" radius="0.025"/>
      </geometry>
    </visual>
  </link>

  <link name="base_rotate">
    <visual>
      <geometry>
    <sphere radius="0.025"/>
      </geometry>
      <origin rpy="0 0 0" xyz="0 0 .1026"/>
      <material name="white"/>
    </visual>
  </link>


  <joint name="base_joint" type="revolute">
    <axis xyz=" 0 0 1"/>
    <parent link="base_link"/>
    <origin rpy="0 0 0" xyz="0 0 0"/>
    <limit effort="1000.0" lower="-3.14159" upper="3.14159" velocity=".5"/>
    <child link="base_rotate"/>
  </joint>

  <link name="first_segment">
    <visual>
      <geometry>
    <cylinder length="0.1180" radius="0.025"/>
      </geometry>
      <origin rpy="0 0 0" xyz="-.0310 0 .059"/>
      <material name="white"/>
    </visual>
  </link>

  <joint name="first_segment_joint" type="revolute">
    <axis rpy="0 1 0" xyz="0 1 0"/>
    <origin rpy="0 0 0" xyz="0 0 .1"/>
    <limit effort="1000.0" lower="-3.14159" upper="3.14159" velocity=".5"/>
    <parent link="base_rotate"/>
    <child link="first_segment"/>
  </joint>

  <link name="second_segment">
    <visual>
      <geometry>
    <cylinder length="0.02" radius="0.025"/>
      </geometry>
      <origin rpy="0 0 0" xyz="0 0 .01"/>
      <material name="white"/>
    </visual>
  </link>

  <joint name="second_segment_joint" type="revolute">
    <axis rpy="0 1 0" xyz="0 1 0"/>
    <origin rpy="0 0 0" xyz="-.0310 0 .1180"/>
    <limit effort="1000.0" lower="-3.14159" upper="3 ...