✨ Your First C++ MoveIt Project Tutorial

[tylerjw]

This adds a initial tutorial walking a user through creating their first program using MoveIt.

Description

This is based on the MoveGroupInterface tutorial here: https://github.com/ros-planning/moveit2_tutorials/blob/main/doc/move_group_interface/src/move_group_interface_tutorial.cpp

[mergify]

This pull request is in conflict. Could you fix it @tylerjw?

[mergify]

This pull request is in conflict. Could you fix it @tylerjw?

[Abishalini]

I was testing this PR and launching the demo file give me this error

[move_group-4] /home/abishalini/ws_tutorials/install/moveit_ros_move_group/lib/moveit_ros_move_group/move_group: symbol lookup error: /home/abishalini/ws_tutorials/install/moveit_simple_controller_manager/lib/libmoveit_simple_controller_manager.so: undefined symbol: _ZN13rclcpp_action10ClientBaseC2ESt10shared_ptrIN6rclcpp15node_interfaces17NodeBaseInterfaceEES1_INS3_18NodeGraphInterfaceEES1_INS3_20NodeLoggingInterfaceEERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEPK28rosidl_action_type_support_tRK27rcl_action_client_options_t
[ERROR] [move_group-4]: process has died [pid 8736, exit code 127, cmd '/home/abishalini/ws_tutorials/install/moveit_ros_move_group/lib/moveit_ros_move_group/move_group --ros-args --params-file /tmp/launch_params_o_rav6lz --params-file /tmp/launch_params_ctt1rnfj --params-file /tmp/launch_params_q1yr1wd2 --params-file /tmp/launch_params_x46drsfd --params-file /tmp/launch_params_6h5inkbh --params-file /tmp/launch_params_a5m6juj4 --params-file /tmp/launch_params_dsraqym_'].

Did anyone come across this?

[destogl]

I am getting the error described in #303 on both, galactic and rolling distributions.

[tylerjw]

I am getting the error described in #303 on both, galactic and rolling distributions.

Thank you for trying this. I read the issue you posted but haven't had time to work on it yet.

[kylc]

After adding the code in step 3, I'm getting an error relating to a missing robot_description parameter in the hello_moveit node.

[ERROR] [1642455060.905388060] [hello_moveit]: Could not find parameter robot_description and did not receive robot_description via std_msgs::msg::String subscription within 10.000000 seconds.
Error:   Error document empty.
         at line 71 in /tmp/binarydeb/ros-rolling-urdfdom-2.3.5/urdf_parser/src/model.cpp
Failed to parse robot description using: urdf_xml_parser/URDFXMLParser
[INFO] [1642455060.907010402] [moveit_rdf_loader.rdf_loader]: Unable to parse URDF
Error:   Error document empty.
         at line 71 in /tmp/binarydeb/ros-rolling-urdfdom-2.3.5/urdf_parser/src/model.cppFailed to parse robot description using: urdf_xml_parser/URDFXMLParser
[INFO] [1642455070.909238553] [moveit_rdf_loader.rdf_loader]: Unable to parse URDF
[FATAL] [1642455070.909728671] [move_group_interface]: Unable to construct robot model. Please make sure all needed information is on the parameter server.
terminate called after throwing an instance of 'std::runtime_error'
  what():  Unable to construct robot model. Please make sure all needed information is on the parameter server.
[ros2run]: Aborted

I believe this is because that parameter is unmapped when running the node via a simple ros2 run command. Adding a launch file like the following and running with ros2 launch fixes the issues for me (copied from the move_group_interface_tutorial.launch.py file):

import os
import yaml
from launch import LaunchDescription
from launch_ros.actions import Node
from ament_index_python.packages import get_package_share_directory


def load_file(package_name, file_path):
    package_path = get_package_share_directory(package_name)
    absolute_file_path = os.path.join(package_path, file_path)

    try:
        with open(absolute_file_path, "r") as file:
            return file.read()
    except EnvironmentError:  # parent of IOError, OSError *and* WindowsError where available
        return None


def load_yaml(package_name, file_path):
    package_path = get_package_share_directory(package_name)
    absolute_file_path = os.path.join(package_path, file_path)

    try:
        with open(absolute_file_path, "r") as file:
            return yaml.safe_load(file)
    except EnvironmentError:  # parent of IOError, OSError *and* WindowsError where available
        return None


def generate_launch_description():
    # planning_context
    robot_description_config = load_file(
        "moveit_resources_panda_description", "urdf/panda.urdf"
    )
    robot_description = {"robot_description": robot_description_config}

    robot_description_semantic_config = load_file(
        "moveit_resources_panda_moveit_config", "config/panda.srdf"
    )
    robot_description_semantic = {
        "robot_description_semantic": robot_description_semantic_config
    }

    kinematics_yaml = load_yaml(
        "moveit_resources_panda_moveit_config", "config/kinematics.yaml"
    )

    # MoveGroupInterface demo executable
    move_group_demo = Node(
        name="hello_moveit",
        package="hello_moveit",
        executable="hello_moveit",
        output="screen",
        parameters=[robot_description, robot_description_semantic, kinematics_yaml],
    )

    return LaunchDescription([move_group_demo])

[tylerjw]

After adding the code in step 3, I'm getting an error relating to a missing robot_description parameter in the hello_moveit node.

[ERROR] [1642455060.905388060] [hello_moveit]: Could not find parameter robot_description and did not receive robot_description via std_msgs::msg::String subscription within 10.000000 seconds.
Error:   Error document empty.
         at line 71 in /tmp/binarydeb/ros-rolling-urdfdom-2.3.5/urdf_parser/src/model.cpp
Failed to parse robot description using: urdf_xml_parser/URDFXMLParser
[INFO] [1642455060.907010402] [moveit_rdf_loader.rdf_loader]: Unable to parse URDF
Error:   Error document empty.
         at line 71 in /tmp/binarydeb/ros-rolling-urdfdom-2.3.5/urdf_parser/src/model.cppFailed to parse robot description using: urdf_xml_parser/URDFXMLParser
[INFO] [1642455070.909238553] [moveit_rdf_loader.rdf_loader]: Unable to parse URDF
[FATAL] [1642455070.909728671] [move_group_interface]: Unable to construct robot model. Please make sure all needed information is on the parameter server.
terminate called after throwing an instance of 'std::runtime_error'
  what():  Unable to construct robot model. Please make sure all needed information is on the parameter server.
[ros2run]: Aborted

The error you are getting is there is something wrong with the loading of the urdf_xml_parser/URDFXMLParser plugin. I think something is wrong with how this plugin is exported. I can't reliably isolate this issue. It happens sometimes and other times it doesn't for me. You don't need to provide robot_description as a parameter to the node using the MoveGroupIterface if there is a running MoveGroup node with these two parameters configured:

        "publish_robot_description": True,
        "publish_robot_description_semantic": True,

Doing ☝️ causes the MoveGroup node to publish the robot_description on a latched topic that the MoveGroupInterface node can subscribe to and get the value.

You'll notice that these two lines are added to the demo.launch.py in this PR so it should be publishing on those two topics.

[abake48]

I ran into the same issue that @kylc experienced. Outside of that, I have a few nitpicky suggestions.

[mergify]

This pull request is in conflict. Could you fix it @tylerjw?

[wyattrees]

Looks good, but I think a couple things need a bit more explanation

[mergify]

This pull request is in conflict. Could you fix it @tylerjw?

[stephanie-eng]

This looks and works great! I highlighted a few areas in need of very minor grammatical fixes, but approved pending those changes.