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Remote Mapping

Robot

For simplification, I will just show nodes/launch files used for mapping. Your robot may have other stuff launched at the same time. Here I assume that the ROS Master is on the robot, and a Kinect is used.

1. [Optional]: To avoid host name resolution issues, set ROS_IP environment variable for the robot:

• $ ifconfig
  eth0      Link encap:Ethernet  HWaddr ##:##:##:##:##:##  
            inet addr:192.168.1.3  Bcast:192.168.1.255  Mask:255.255.255.0
  ...
  $ export ROS_IP=192.168.1.3

2. We will throttle the Kinect messages on the robot at 5 Hz to reduce the bandwidth used on the network (reducing latency). We also want to pre-sync camera topics before sending them over the network. To do both, we can use rtabmap_ros/rgbd_sync nodelet for convenience. Create a file called freenect_throttle.launch and copy/paste this code:

• <launch>
    <include file="$(find freenect_launch)/launch/freenect.launch">
       <arg name="depth_registration" value="True" />
    </include>
  
    <arg name="rate"  default="5"/>
    <arg name="approx_sync" default="true" /> <!-- true for freenect driver -->
  
    <!-- Use same nodelet used by Freenect/OpenNI -->
    <group ns="camera">
      <node pkg="nodelet" type="nodelet" name="data_throttle" args="load rtabmap_ros/rgbd_sync camera_nodelet_manager" output="screen">
        <param name="compressed_rate"  type="double" value="$(arg rate)"/>
        <param name="approx_sync"      type="bool"   value="$(arg approx_sync)"/>
  
        <remap from="rgb/image"       to="rgb/image_rect_color"/>
        <remap from="depth/image"     to="depth_registered/image_raw"/>
        <remap from="rgb/camera_info" to="rgb/camera_info"/>
  
        <remap from="rgbd_image"      to="rgbd_image"/>
      </node>
    </group>      
  </launch>

3. Launch the file:

• $ roslaunch freenect_throttle.launch rate:=5

Remote Client Computer

On the client computer, we will launch rtabmap, rgbd_odometry and rtabmapviz using rtabmap.launch for convenience. For efficiency and to not subscribe to same topics multiple time on the robot, rtabmap.launch will use relays and rgbd_relay to subscribe just once to incoming topics from the robot and relay the messages to multiples nodes on the client side.

1. [Optional]: To avoid host name resolution issues, set ROS_IP environment variable for the client:

• $ ifconfig
  eth0      Link encap:Ethernet  HWaddr ##:##:##:##:##:##  
            inet addr:192.168.1.2  Bcast:192.168.1.255  Mask:255.255.255.0
  ...
  $ export ROS_IP=192.168.1.2

2. Set ROS_MASTER_URI with the robot IP/hostname:

• $ export ROS_MASTER_URI=http://192.168.1.3:11311

3. Launch rtabmap.launch (Warning with rtabmap_ros 0.10 binaries: Please use the updated launch file on master branch linked here instead of the one installed with the rtabmap_ros 0.10 binaries):

• $ roslaunch rtabmap_ros rtabmap.launch subscribe_rgbd:=true rgbd_topic:=/camera/rgbd_image compressed:=true rtabmap_args:="--delete_db_on_start"

4. You should now see mapping in rtabmapviz window.

5. If you open the System Monitor of Ubuntu, you should have something like ~500 KiB/s of bandwidth used:

Advanced

1. If you have already odometry on the robot, you can set arguments visual_odometry:=false and odom_topic:="/odom".

2. You can use launch rviz manually or with argument rviz:=true for convenience. If you don't want rtabmapviz, you can disable it using rtabmapviz:=false argument.