Thank you for updates. To review, open the file in an editor that reveals hidden Unicode characters. When the battery gets low, we want the robot to automatically go to a charging station (also known as docking station) to recharge its battery. Furthermore, I couldn't find any arguments in launch file using -s or --show-arguments after activate DeclareLaunchArgument. Note: this for ROS2 version Dashing Share Follow edited Sep 2, 2019 at 10:51 answered Aug 28, 2019 at 16:22 Floris Devreese We start by creating a ROS 2 package using ros2pkgcreate<pkg-name>--dependencies[deps]in our workspace and creating a new launchdirectory. parameter_descriptions import ParameterValue def generate_launch . So I can declare it by using launch.actions.DeclareLaunchArgument ( 'param1', default_value="defaultString") and access it later using launch.substitutions.LaunchConfiguration ( 'param1') to pass it to a node or whatever. Cannot retrieve contributors at this time. ', # Create the launch description and populate, # Add the actions to launch all of the navigation nodes. Hi @relffok, have you figured out how to use a launch argument as a string? By voting up you can indicate which examples are most useful and appropriate. I think you can still do what you want though as far as building paths based on an argument by passing in an array and have the path concat'd at run time. # args that can be set from the command line or a default will be used, 'launch/topics/talker_listener.launch.py', # include another launch file in the chatter_ns namespace, # push_ros_namespace to set namespace of included nodes, # start a turtlesim_node in the turtlesim1 namespace, # start another turtlesim_node in the turtlesim2 namespace, # perform remap so both turtles listen to the same command topic, forward_turtlesim_commands_to_second_turtlesim_node, , "$(find-pkg-share demo_nodes_cpp)/launch/topics/talker_listener.launch.py", , , , , demo_nodes_cpp)/launch/topics/talker_listener.launch.py", # start another turtlesim_node in the turtlesim2 namespace and use args to set parameters, ros2 launch , ros2 launch background_r:=255, ros2 launch background_r:=255, ros2 run turtlesim turtle_teleop_key --ros-args --remap __ns:=/turtlesim1, Migrating launch files from ROS 1 to ROS 2, ROS 2 Iron Irwini (codename iron; May, 2023), Writing a simple publisher and subscriber (C++), Writing a simple publisher and subscriber (Python), Writing a simple service and client (C++), Writing a simple service and client (Python), Writing an action server and client (C++), Writing an action server and client (Python), Composing multiple nodes in a single process, Integrating launch files into ROS 2 packages, Running Tests in ROS 2 from the Command Line, Building a visual robot model from scratch, Using Fast DDS Discovery Server as discovery protocol [community-contributed], Unlocking the potential of Fast DDS middleware [community-contributed], Using quality-of-service settings for lossy networks, Setting up efficient intra-process communication, Creating a content filtering subscription, Deploying on IBM Cloud Kubernetes [community-contributed], Building a real-time Linux kernel [community-contributed], Using Python, XML, and YAML for ROS 2 Launch Files, Using ROS 2 launch to launch composable nodes, Migrating YAML parameter files from ROS 1 to ROS 2, Passing ROS arguments to nodes via the command-line, Synchronous vs. asynchronous service clients, Working with multiple ROS 2 middleware implementations, Running ROS 2 nodes in Docker [community-contributed], Visualizing ROS 2 data with Foxglove Studio, Building ROS 2 with tracing instrumentation, On the mixing of ament and catkin (catment), ROS 2 Technical Steering Committee Charter. @relffok I know this is an old issue, but someone bumped it from another place, and it might help others for me to clarify. A LaunchConfiguration cannot be required to be set when launching or including and it is not possible to set it when launching from the command line. Allowing them to be listed, set, or marked as required when a user launches it from the command line (using ros2 launch) or when including it from another launch file (using IncludeLaunchDescription ). T n u nm 2019, huyn Quan Ha c 18 n v hnh chnh cp x, bao gm th trn Quan Ha v 17 x: Hin Chung, Hin Kit, Hi Xun, Nam ng, Nam Tin, Nam Xun, Ph L, Ph Nghim, Ph Sn, Ph Thanh, Ph Xun, Thnh Sn, Thanh Xun, Thin Ph, Trung Sn, Trung Thnh . While there are a variety of mapping options in ROS1 and some in ROS2, for localization it really is just Adaptive Monte Carlo Localization (AMCL). This guide shows how to use these different formats to accomplish the same task, as well as has some discussion on when to use each format. There is some ongoing work towards more modern localization solutions in ROS2, but it would seem to be a long way off. launch.actions.DeclareLaunchArgument By T Tak Here are the examples of the python api launch.actions.DeclareLaunchArgumenttaken from open source projects. Quan Ha t chc Cuc thi KHKT cp huyn, dnh cho hc sinh Trung hc c s nm hc 2022- 2023. Now I want to use the content of this argument as a string for building filepaths for example. ros2 pkg create launch_tutorial --build-type ament_python Inside of that package, create a directory called launch: mkdir launch_tutorial/launch Finally, make sure to add in changes to the setup.py of the package so that the launch files will be installed: To try them locally, you can either create a new package and use. A tag already exists with the provided branch name. That being said, a launch file written in Python may be more complex and verbose than one in XML or YAML. A tag already exists with the provided branch name. @fastestindian, It is the wrong way to deal with substitutions, once you have substitution the content of it cannot be used before all substitutions can be resolved. The type of this element is a launch.substitutions.launch_configuration.LaunchConfiguration object. Define custom messages in python package (ROS2). DeclareLaunchArgument allows you to expose the argument outside of your launch file. After fixing a bug I can see the arguments, so maybe you need to give more details? Using the Launch files from the command line. However, if your launch file requires flexibility that you cannot achieve with XML or YAML, you can use Python to write your launch file. # Map fully qualified names to relative ones so the node's namespace can be prepended. ROS2rviz2urdf . Trang ch Th hai, ngy 5 thng 12 nm 2022. Passing an array of arrays of doubles from a yaml config file, [ROS2] what is different between DeclareLaunchArgument and LaunchConfiguration, Creative Commons Attribution Share Alike 3.0. Unfortunately I need to access the arguments as a string type because the LaunchConfiguration element can only be read by launch action functions and I want to use them with other functions as well. ros2 launch -s basic_mobile_robot basic_mobile_bot_v1.launch.py. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. [ROS2] What's the best way to wait for a new message? # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. For example, you can set the value of background_r in the following way: ros2 launch <package_name> <launch_file_name> background_r:=255 or ros2 launch <path_to_launch_file> background_r:=255 Parse yaml from file, given its absolute file path. DeclareLaunchArgument allows you to expose the argument outside of your launch file. LaunchConfiguration is local to the launch file and scoped. Open a web shell and run the following command: user:~$ cd ~/ros2_wsuser:~/ros2_ws$ source install/setup.bash user:~/ros2_ws$ ros2 launch box_bot_gazebo box_bot_launch.py. Others have proposed a more imperative version of the Python API for launch, but that doesn't exist at the moment. # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. ros2 launch <path_to_launch_file>. In my simplified case: If launch.substitutions.LaunchConfiguration('urdf') is passed as a list I get a "join() argument must be str or bytes, not 'list'".If I dont, I get join() argument must be str or bytes, not 'LaunchConfiguration' Is there an easy way to get the text value of the argument? Applied when composition is disabled. You're reading the documentation for a development version. This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository. Using Python for ROS 2 launch is more flexible because of following two reasons: Python is a scripting language, and thus you can leverage the language and its libraries in your launch files. The Python API is really meant to help implement the markup based frontends like YAML and XML, and so it is declarative rather than imperative. It appears that Foxy has had the feature added. However, if I set LaunchConfiguration excluding DeclareLaunchArgument, I would access launch argument from the command line. You should see a simulation similar to this one: Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch? Thank you! Open the Gazebo app (if it does not open automatically). The arguments are successfully implemented using only set LaunchConfiguration exclude DeclareLaunchArgument. I was able to evaluate launch arguments in a custom function outside of the LaunchDescription by using the OpaqueFunction launch action feature which takes a context as an argument, see this link: Please start posting anonymously - your entry will be published after you log in or create a new account. So, my main questions is What is different btw LaunchConfiguration and DeclareLaunchArgument? Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. # See the License for the specific language governing permissions and, # Create the launch configuration variables. You either have to create a custom substitution or use an existing one: Thanks again! Using a substitution is the only way to access the value of the launch argument. In child.launch.py you read in the passed argument like this: from launch.substitutions import LaunchConfiguration def generate_launch_description (): value= LaunchConfiguration ('argument_for_child', default='-') . I can't believe that this is not possible yet because I feel its a very basic and handy action to use. I don't understand this, can you try to rephrase it? substitutions import LaunchConfiguration , ThisLaunchFileDir I know several functions are able to interpret the LaunchConfiguration object but I specifically to read it as a string. The type of this element is a launch.substitutions.launch_configuration.LaunchConfiguration object. # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. Launch the Model Manually Launch the Model Automatically Create the Launch File Build the Package Launch the Launch File Prerequisites ROS 2 Foxy Fitzroy installed on Ubuntu Linux 20.04 or newer. # See the License for the specific language governing permissions and, "Start robot with fake hardware mirroring command to its states.". Learn more about bidirectional Unicode characters. substitutions import FindPackageShare from launch. Launching. You signed in with another tab or window. For the latest released version, please have a look at Humble. 97 Examples 7 12next 3View Source File : data_collection.launch.py License : MIT License Project Creator : dusty-nv I'm trying to pass an argument (file path) to open(yaml_file, 'r').read() function and it gives me the following error when I launch it: I don't believe you can access the argument during building of the description. substitutions import Command from launch_ros. If I give the argument hardware:=rpi1 then my main launch file will include launch file rpi1.launch.py instead of the default hardware.launch.py in it's launch description: Declare the launch argument, then use the launch argument in a build-path statement to include my parameterized launch file: Thanks for your answer. Hi, If this is confusing, then you might want to stick with xml based launch files as it is more natural to adhere to this restriction there. light169. actions import DeclareLaunchArgument from launch. Automatic Docking to a Battery Charging Station - ROS 2. from launch.actions import DeclareLaunchArgument from launch.actions import IncludeLaunchDescription from launch.conditions import IfCondition from launch.launch_description_sources import PythonLaunchDescriptionSource from launch.substitutions import LaunchConfiguration from launch.substitutions import ThisLaunchFileDir def generate_launch . from launch. I actually found out that the --show-arguments option was broken while testing this, so I'm not sure if that's what you ran into, but I open a pr to fix: With that fix I can check the arguments (ros2 launch -s ./test.launch.py): I can run it if I specify other (ros2 launch ./test.launch.py other:='lorem ipsum'): Thank you for comments :) I did know the possibility using an array. # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # You may obtain a copy of the License at, # http://www.apache.org/licenses/LICENSE-2.0, # Unless required by applicable law or agreed to in writing, software. To see whats changed, you can visit Migrating launch files from ROS 1 to ROS 2. Define custom messages in python package (ROS2), Incorrect Security Information - Docker GUI. You signed in with another tab or window. Load yaml configuration based on package name and file path relative to its share. could not find any instance of Visual Studio. :ROS2parameter: -class type- ROS2YAML YAMLYAML Hope this helps, and sorry that it's confusing. Python Packages For Python packages, your directory should look like this: src/ Are you sure you want to create this branch? I have tested it in Ubuntu18.04 and ROS2 Dashing(master repo). The DeclareLaunchArgument command sets the default value of the string 'use_rviz', which is True in the case of our launch file . Access launch argument in LaunchFile ROS2, Creative Commons Attribution Share Alike 3.0. Here's an example I threw together demonstrate based on comments to this answer: If I try to launch it without arguments (ros2 launch ./test.launch.py) I get: That's because the other option has no default value and therefore is required. Each launch file performs the following actions: Setup command line arguments with defaults, Include another launch file in another namespace, Start a node, setting its namespace, and setting parameters in that node (using the args), Create a node to remap messages from one topic to another, Any of the launch files above can be run with ros2 launch. If I erase LaunchConfiguration, I would not. A tag already exists with the provided branch name. For example, I want to specify the underlying hardware launch file as an argument. This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. Python, XML, or YAML: Which should I use? if I set LaunchConfiguration excluding DeclareLaunchArgument, I would access launch argument from the command line. LaunchConfiguration is local to the launch file and scoped. actions import Node from launch_ros. # You may obtain a copy of the License at, # http://www.apache.org/licenses/LICENSE-2.0, # Unless required by applicable law or agreed to in writing, software. If I erase LaunchConfiguration, I would not. ros2 launch <package_name> <launch_file_name>. launch_description_sources import PythonLaunchDescriptionSource from launch . ROS 2 launch files can be written in Python, XML, and YAML. or run the file directly by specifying the path to the launch file. Huyn Quan Ha. 4 comments ryanewel commented on Jul 25, 2019 nuclearsandwich added the bug label on Aug 15, 2019 One way to create launch files in ROS 2 is using a Python file, which are executed by the ROS 2 CLI tool, ros2launch. However, most examples of ros2 launch are included DeclareLaunchArgument when user want to use arguments. Below is a launch file implemented in Python, XML, and YAML. ros2/launch (general launch features) and ros2/launch_ros (ROS 2 specific launch features) are written in Python and thus you have lower level access to launch features that may not be exposed by XML and YAML. For example, attached launch files worked excluding DeclareLaunchArgument. I am using ROS 2 Galactic, which is the latest version of ROS 2 as of the date of this post. Generate list of all launch arguments that are declared for this launch script. This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository. As I need to access multiple arguments several times, I am looking for a simple implementation. I'm struggling with the concept of substitutions. So I can declare it by using launch.actions.DeclareLaunchArgument( 'param1', default_value="defaultString") and access it later using launch.substitutions.LaunchConfiguration( 'param1') to pass it to a node or whatever. # distributed under the License is distributed on an "AS IS" BASIS. I updated my answer with my demo. from launch import launchdescription from launch.actions import declarelaunchargument from launch.actions import executeprocess from launch.substitutions import launchconfiguration def generate_launch_description (): return launchdescription ( [ declarelaunchargument ('topics', default_value= ['-a'], description='topics to record'), I had tested ros2 launch with arguments. I could check launch arguments using -s and I clearly understand what is a different of them. You can set a LaunchConfiguration before including another launch file, but an argument is better if you want it to be reused. ros2 launch cpp_pubsub declare_test.launch.py --show-args: Here is the output you will be able to achieve after completing this tutorial: Prerequisites Create a tf Listener Create the Charging Dock Create the World Build the Package Load the World Autonomous Docking Without ARTag Vision Create the Script Edit CMakeLists.txt Create the Launch File Update the Parameters Launch the Robot References https://github.com/ros2/launch/tree/m For your use-case, you can use PathJoinSubstitution, something like: Please start posting anonymously - your entry will be published after you log in or create a new account. You have already created a ROS 2 workspace. The launch file we copied over for running the map_server also included AMCL in . You can't just convert it to a string, as it requires the context to be evaluated. # distributed under the License is distributed on an "AS IS" BASIS. To set the arguments that are passed to the launch file, you should use key:=value syntax. DeclareLaunchArgument launch . Cannot retrieve contributors at this time. To review, open the file in an editor that reveals hidden Unicode characters. Is there a good way to get the argument value? Learn more about bidirectional Unicode characters. For example, you can set the value of background_r in the following way: To test that the remapping is working, you can control the turtles by running the following command in another terminal: Launch files in ROS 1 were written in XML, so XML may be the most familiar to people coming from ROS 1. description="Path to xacro or URDF description of the robot, relative to share of `description_package`.", # Copyright 2021 Stogl Robotics Consulting UG (haftungsbeschrnkt). I've been trying to Use my Launch Arguments inside of my Launch File for further purposes. Step 4: Launch the Simulation and Rviz2 to see the RGB camera. ros2 launch <path_to_launch_file> Setting arguments To set the arguments that are passed to the launch file, you should use key:=value syntax. To try them locally, you can either create a new package and use, or run the file directly by specifying the path to the launch file. actions import DeclareLaunchArgument, IncludeLaunchDescription from launch . Khai mc Hi ngh ton quc nghin cu, hc tp, qun trit Ngh quyt Hi ngh ln th 6, Ban Chp hnh Trung ng . This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. Any of the launch files above can be run with ros2 launch . For most applications the choice of which ROS 2 launch format comes down to developer preference. "Enable fake command interfaces for sensors used for simple simulations. from launch_ros. launch the robot without RViz), you can do something like this (this is a single command): . I have not found a way to do so. And if you want to set the value of an argument (e.g. # In case of the transforms (tf), currently, there doesn't seem to be a better alternative, # https://github.com/ros/geometry2/issues/32, # https://github.com/ros/robot_state_publisher/pull/30, # TODO(orduno) Substitute with `PushNodeRemapping`, # https://github.com/ros2/launch_ros/issues/56, 'Whether to apply a namespace to the navigation stack', 'Full path to the ROS2 parameters file to use for all launched nodes', 'Whether to respawn if a node crashes. "Start RViz2 automatically with this launch file.". Allowing them to be listed, set, or marked as required when a user launches it from the command line (using ros2 launch) or when including it from another launch file (using IncludeLaunchDescription). ros-planning / navigation2 Public Notifications Fork 788 Star 1.3k Code Issues 50 Pull requests 19 Actions Projects Security Insights main navigation2/nav2_bringup/launch/bringup_launch.py Go to file stevedanomodolor Use SetParameter Launch API to set the yaml filename for map_server ( # Latest commit a03cb63 26 days ago History 7 contributors In this tutorial, I will show you how to create an autonomous docking application for a two-wheeled mobile robot.