Move UR with a MoveIt2 Script

ROS
1

I try to run a simple script to move my ur3e with moveit2. I also use ROS2 Humble.
I did the moveit2 tutorial to get started.
I created a new package hello_moveit_ur and a new file hello_moveit_ur.cpp.
Then i took a simple Script which includes the Pandas Arm and tried to change it to the UR.

#include <memory>

#include <rclcpp/rclcpp.hpp>
#include <moveit/move_group_interface/move_group_interface.h>

int main(int argc, char * argv[])
{
  // Initialize ROS and create the Node
  rclcpp::init(argc, argv);
  auto const node = std::make_shared<rclcpp::Node>(
    "hello_moveit",
    rclcpp::NodeOptions().automatically_declare_parameters_from_overrides(true)
  );

  // Create a ROS logger
  auto const logger = rclcpp::get_logger("hello_moveit");

  // Create the MoveIt MoveGroup Interface
using moveit::planning_interface::MoveGroupInterface;
auto move_group_interface = MoveGroupInterface(node, "ur_manipulator"); //change

// Set a target Pose
auto const target_pose = []{
  geometry_msgs::msg::Pose msg;
  msg.orientation.w = 1.0;
  msg.position.x = 0.28;
  msg.position.y = -0.2;
  msg.position.z = 0.5;
  return msg;
}();
move_group_interface.setPoseTarget(target_pose);

// Create a plan to that target pose
auto const [success, plan] = [&move_group_interface]{
  moveit::planning_interface::MoveGroupInterface::Plan msg;
  auto const ok = static_cast<bool>(move_group_interface.plan(msg));
  return std::make_pair(ok, msg);
}();

// Execute the plan
if(success) {
  move_group_interface.execute(plan);
} else {
  RCLCPP_ERROR(logger, "Planing failed!");
}

  // Shutdown ROS
  rclcpp::shutdown();
  return 0;
}

When i run it, i get following error:

ros2 run hello_moveit_ur hello_moveit_ur 
[ERROR] [1666178490.810279739] [hello_moveit]: Could not find parameter robot_description_semantic and did not receive robot_description_semantic via std_msgs::msg::String subscription within 10.000000 seconds.
Error:   Could not parse the SRDF XML File. Error=XML_ERROR_EMPTY_DOCUMENT ErrorID=13 (0xd) Line number=0
         at line 715 in /home/luca/ws_moveit2/src/srdfdom/src/model.cpp
[ERROR] [1666178490.815432620] [moveit_rdf_loader.rdf_loader]: Unable to parse SRDF
[FATAL] [1666178490.815622448] [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

What did i miss?

1 Like
2

I had o give the necessary parameters with a launchfile:

import launch
import os
import sys

from launch_ros.actions import Node
from launch.substitutions import PathJoinSubstitution, Command, FindExecutable
from launch_ros.substitutions import FindPackageShare

def get_robot_description():
    joint_limit_params = PathJoinSubstitution(
        [FindPackageShare("ur_description"), "config", "ur3e", "joint_limits.yaml"]
    )
    kinematics_params = PathJoinSubstitution(
        [FindPackageShare("ur_description"), "config", "ur3e", "default_kinematics.yaml"]
    )
    physical_params = PathJoinSubstitution(
        [FindPackageShare("ur_description"), "config", "ur3e", "physical_parameters.yaml"]
    )
    visual_params = PathJoinSubstitution(
        [FindPackageShare("ur_description"), "config", "ur3e", "visual_parameters.yaml"]
    )
    robot_description_content = Command(
        [
            PathJoinSubstitution([FindExecutable(name="xacro")]),
            " ",
            PathJoinSubstitution([FindPackageShare("ur_description"), "urdf", "ur.urdf.xacro"]),
            " ",
            "robot_ip:=172.17.0.2",
            " ",
            "joint_limit_params:=",
            joint_limit_params,
            " ",
            "kinematics_params:=",
            kinematics_params,
            " ",
            "physical_params:=",
            physical_params,
            " ",
            "visual_params:=",
            visual_params,
            " ",
           "safety_limits:=",
            "true",
            " ",
            "safety_pos_margin:=",
            "0.15",
            " ",
            "safety_k_position:=",
            "20",
            " ",
            "name:=",
            "ur",
            " ",
            "ur_type:=",
            "ur3e",
            " ",
            "prefix:=",
            '""',
            " ",
        ]
    )


    robot_description = {"robot_description": robot_description_content}
    return robot_description

def get_robot_description_semantic():
    # MoveIt Configuration
    robot_description_semantic_content = Command(
        [
            PathJoinSubstitution([FindExecutable(name="xacro")]),
            " ",
            PathJoinSubstitution([FindPackageShare("ur_moveit_config"), "srdf", "ur.srdf.xacro"]),
            " ",
            "name:=",
            # Also ur_type parameter could be used but then the planning group names in yaml
            # configs has to be updated!
            "ur",
            " ",
            "prefix:=",
            '""',
            " ",
        ]
    )
    robot_description_semantic = {
        "robot_description_semantic": robot_description_semantic_content
    }
    return robot_description_semantic
    
def generate_launch_description():
    # generate_common_hybrid_launch_description() returns a list of nodes to launch
    robot_description = get_robot_description()
    robot_description_semantic = get_robot_description_semantic()
    demo_node = Node(
        package="hello_moveit_ur",
        executable="hello_moveit_ur",
        name="hello_moveit_ur",
        output="screen",
        parameters=[
            robot_description,
            robot_description_semantic,
        ],
    )

    return launch.LaunchDescription([demo_node])

When I start

ros2 launch ur_robot_driver ur_control.launch.py ur_type:=ur3e robot_ip:=192.168.1.102 launch_rviz:=false initial_joint_controller:=joint_trajectory_controller
then activate the external control urcap
then
ros2 launch ur_moveit_config ur_moveit.launch.py ur_type:=ur3e launch_rviz:=true
then
ros2 launch hello_moveit_ur hello_moveit_ur_launch.py
the Robot moves to the target position.

The topic was also discussed here: ur10 cannot find robot_descrition semantic in ros humble · Issue #457 · UniversalRobots/Universal_Robots_ROS2_Driver · GitHub
My files can be found here: GitHub - LucaBross/simple_moveit2_universal_robots_movement

3

My externalcontrol program show tool contant not defined compilation error. I am working in ros2 humble with ur5 robot.The externalcontrol.urcap program version is 1.0.5. please help me to address this issue.