universal_robot_ign

universal_robot_ign : Run universal robot in Ignition Gazebo simulator .

It provides SDF models of universal robot for Ignition Gazebo. In addition, it also provides a moveit2 application demo and simple grasp demo with Gripper Robotiq140 .

1. Usage

Install

• ROS: foxy
• Ignition :Dome

#install dependency
sudo apt-get install ros-foxy-joint-state-publisher-gui
#cd src of ros2 workspace and download source code
git clone https://github.com/gezp/universal_robot_ign.git
#cd ros2 workspace and build
colcon build

UR10 moveit2 demo

• use moveit2 and joint_trajectory_controller to control UR10.

moveit2 should be installed: MoveIt 2 Source Build - Linux

launch Ignition Gazebo simulator for UR10

ros2 launch universal_robot_ign ur10_ign.launch.py 

• ur10_ign uses joint_trajectory_controller

launch moveit2 move_group action server for UR10.

ros2 launch universal_robot_ign ur10_moveit2_demo.launch.py 

run moveit2 client node, plan to goal

ros2 run universal_robot_ign test_pose_goal.py

• start position <-> goal pose: [-0.0, 0.4, 0.6, 0.0, 0.0, 0.0] (loop)

the result:

UR10 + Robotiq140 Grasp demo

• control gripper Robotiq140 to grasp object and control UR10 based on joint position.

launch Ignition Gazebo simulator for UR10 + Robotiq140

ros2 launch universal_robot_ign ur10_robotiq140_ign.launch.py 

• use joint_position_controller to control UR10.
• use Ignition plugin RobotiqController to control Robotiq140.

run gripper test node to grasp stick model by closing gripper

ros2 run universal_robot_ign test_gripper.py 
#1 : close gripper to grasp.
#0 : open gripper.

launch joint state publisher GUI to control UR10 based on joint position

ros2 launch universal_robot_ign ur10_robotiq140_demo.launch.py

the result:

No Gripper slipping in Ignition Gazebo!

• There is Gripper Slipping Problem on Gazebo-classic which need use plugin to add fxied joint between object and gripper when grasp.

2. models

the package contains robotic arm universal_robot SDF models (ur3,ur5,ur10) , a robotic gripper SDF models (robotiq140 ) ,and a combination model ur10_robotiq140 .

• the sdf files of these models are written modularly by use xacro4sdf which is a xml macro tool.
• it's easy to combine different model, for example, ur10_robotiq140 is ur10 robotic arm attached robotiq140 gripper .

3. Controller

Controller Struture

Ignition Controller

• Ignition plugin ignition-gazebo-joint-position-controller-system is used to control joints of robotic arm .
• The position PID parameter should be set in plugins.

PID parameter：

• The PID parameter of Ignition joint position controller plugin is set roughly ,so the performance of control is not well, you can modify PID parameter by modifying SDF file of model.

ROS controller

• joint_position_controller
  • receive ROS msg sensor_msgs::msg::JointState and publish target position ignition::msgs::Double for each joint (control based on position pid) .
  • it's a simple communication bridge
• joint_trajectory_controller
  • receive ROS msg trajectory_msgs::msg::JointTrajectory
  • use interpolation based on time for joint trajectory and keep publishing target position according to current time until the last trajectory point is processed .
  • this is not the most efficient way, but easy to Implement (it can work well with moveit2)

4. Maintainer and License

Maintainer : Zhenpeng Ge, [email protected]

universal_robot_ign is provided under MIT License.

• the 3d model is from ros-industrial/universal_robot and ros-industrial/robotiq which are provided under BSD License.
• some code snippets is from ign_moveit2 for ur10 moveit2 demo .