Hi,

I receive this message if I start my launch file:

[ERROR] 4.264000000: Client [/move_base] wants topic /base_laser to have 
datatype/md5sum 
[sensor_msgs/PointCloud/d8e9c3f5afbdd8a130fd1d2763945fca], but our 
version has [sensor_msgs/LaserScan/90c7ef2dc6895d81024acba2ac42f369]. 
Dropping connection.


I use a simulated laser my launch file look like this:

<launch>
  <!-- start world -->
  <include file="$(find gazebo_worlds)/launch/office_world.launch"/>

  <!-- start controller manager (rviz) -->
  <include file="$(find pr2_controller_manager)/controller_manager.launch"/>

  <!-- load AILA rover -->
  <param name="robot_description" textfile="$(find 
my_controller_pkg)/ailarover.xml" />

  <!-- push robot_description to factory and spawn robot in gazebo -->
  <node name="spawn_single_link" pkg="gazebo_tools" type="gazebo_model" 
args="-p robot_description spawn -z 2" respawn="false" output="screen" />


  <!--include file="$(find pr2_gazebo)/pr2.launch"/-->

   <rosparam file="$(find my_controller_pkg)/my_controller.yaml" 
command="load" />

   <node pkg="pr2_controller_manager" type="spawner" 
args="my_controller_ns" name="my_controller_spawner" />


  <!-- Run the map server -->
  <node name="map_server" pkg="map_server" type="map_server" 
args="$(find my_controller_pkg)/config/office.png 0.05"/>
  <node pkg="tf" type="static_transform_publisher" 
name="base_laser_to_base_link" args="0 0 0 1.57 0 0 base_link base_laser 
100" />
  <node pkg="tf" type="static_transform_publisher" 
name="base_footprint_to_base_link" args="0 0 0 0 0 1.57 base_link 
base_footprint  20" />

  <!--- Run AMCL -->
  <include file="$(find my_controller_pkg)/config/amcl.xml" />

  <node pkg="move_base" type="move_base" respawn="false" 
name="move_base" output="screen">
    <rosparam file="$(find 
my_controller_pkg)/config/costmap_common_params.yaml" command="load" 
ns="global_costmap" />
    <rosparam file="$(find 
my_controller_pkg)/config/costmap_common_params.yaml" command="load" 
ns="local_costmap" />
    <rosparam file="$(find 
my_controller_pkg)/config/local_costmap_params.yaml" command="load" />
    <rosparam file="$(find 
my_controller_pkg)/config/global_costmap_params.yaml" command="load" />
    <rosparam file="$(find 
my_controller_pkg)/config/base_local_planner_params.yaml" command="load" />
  </node>
</launch>

and my laser is here in the costmap yaml:

observation_sources: base_scan

base_scan: {sensor_frame: base_laser_link, data_type: LaserScan, 
expected_update_rate: 0.2,
  observation_persistence: 0.0, marking: false, clearing: true, 
min_obstacle_height: -0.08, max_obstalce_height: 2.0}