Yes, you can use roslaunch
to launch multiple nodes at once and you can even include other launch files (from other packages!) within a separate launch file. Let's use the turtlebot_simulator
metapackage as an example.
Here's the code for the launch file that brings up a gazebo
simulation of the turtlebot (turtlebot_world.launch
) :
<launch>
<arg name="world_file" default="$(env TURTLEBOT_GAZEBO_WORLD_FILE)"/>
<arg name="base" value="$(optenv TURTLEBOT_BASE kobuki)"/> <!-- create, roomba -->
<arg name="battery" value="$(optenv TURTLEBOT_BATTERY /proc/acpi/battery/BAT0)"/> <!-- /proc/acpi/battery/BAT0 -->
<arg name="gui" default="true"/>
<arg name="stacks" value="$(optenv TURTLEBOT_STACKS hexagons)"/> <!-- circles, hexagons -->
<arg name="3d_sensor" value="$(optenv TURTLEBOT_3D_SENSOR kinect)"/> <!-- kinect, asus_xtion_pro -->
<include file="$(find gazebo_ros)/launch/empty_world.launch">
<arg name="use_sim_time" value="true"/>
<arg name="debug" value="false"/>
<arg name="gui" value="$(arg gui)" />
<arg name="world_name" value="$(arg world_file)"/>
</include>
<include file="$(find turtlebot_gazebo)/launch/includes/$(arg base).launch.xml">
<arg name="base" value="$(arg base)"/>
<arg name="stacks" value="$(arg stacks)"/>
<arg name="3d_sensor" value="$(arg 3d_sensor)"/>
</include>
<node pkg="robot_state_publisher" type="robot_state_publisher" name="robot_state_publisher">
<param name="publish_frequency" type="double" value="30.0" />
</node>
<!-- Fake laser -->
<node pkg="nodelet" type="nodelet" name="laserscan_nodelet_manager" args="manager"/>
<node pkg="nodelet" type="nodelet" name="depthimage_to_laserscan"
args="load depthimage_to_laserscan/DepthImageToLaserScanNodelet laserscan_nodelet_manager">
<param name="scan_height" value="10"/>
<param name="output_frame_id" value="/camera_depth_frame"/>
<param name="range_min" value="0.45"/>
<remap from="image" to="/camera/depth/image_raw"/>
<remap from="scan" to="/scan"/>
</node>
</launch>
This launch file includes both other launch files and several nodes. Here is how it includes other launch files:
<include file="$(find gazebo_ros)/launch/empty_world.launch">
<arg name="use_sim_time" value="true"/>
<arg name="debug" value="false"/>
<arg name="gui" value="$(arg gui)" />
<arg name="world_name" value="$(arg world_file)"/>
</include>
and here is how it includes other nodes:
<node pkg="robot_state_publisher" type="robot_state_publisher" name="robot_state_publisher">
<param name="publish_frequency" type="double" value="30.0" />
</node>
You could simply include a launch file without args
or params
like this:
<include file="$(find package_name)/launchfile.launch"/>
or similarly for a node:
<node pkg="package" type="node_type" name="node_name"/>
Please refer to the roslaunch
wiki entry for more details, or ask another question.
You can also use launch files to load parameters and to launch nodes on different machines as well.