Mobile_Robot_Base_With_Arm_In_Gazebo

Abstract

This package contains a URDF model of a differential drive robot equipped with a camera and biaxial arm.

Requirements

The ROS packages of diff_drive_controller,camera_controller ,joint_state_controller and joint_pose_trajectory_controller are required.

For example, you can install these requirements on Ubuntu 22.04.4 LTS by the following command:

sudo apt install ros-humble-gazebo-ros-pkgs

Repository architecture

Directories

• my_robot_bringup/

  • launch/ : (optional) contains launch files for starting the simulation / running of the model in gazebo
  • rviz/ : (optional) contains Rviz configuration settings for displaying the robot model
  • worlds/ : (optional) contains scene/environment files for Gazebo

• my_robot_description/

  • launch/ : (optional) contains launch files for starting the simulation / running urdf model and checking the TF's
  • rviz/ : (optional) contains Rviz configuration settings for displaying the robot model
  • urdf/ : (required) contains the files that generate the robot model and provide simulated actuators and sensors
    • arm.xacro : the xacro file that generates the urdf description file of the arm
    • arm_gazebo.xacro : contains the Gazebo plugins that provide an interface to control the arm
    • camera.xacro : contains the Gazebo plugins that provide an interface to control the camera
    • common_properties.xacro : contains the common properties like different materials and macros for inertia of different geometries
    • mobile_base.xacro : the xacro file that generates the urdf description file of the mobile base of the robot
    • mobile_base_gazebo.xacro : contains the Gazebo plugins that provide an interface to control the robot wheels with differential drive
    • my_robot.urdf.xacro : includes all xacro files which are required for the robot to spawn in gazebo

Direct usage

• Clone this repository into a ROS catkin workspace
• Build and source the workspace
• To view this robot model on RViz: $ ros2 launch my_robot_description display.launch.xml
• To launch this package in test Gazebo world and Rviz: $ ros2 launch my_robot_bringup my_robot_gazebo.launch.xml

Gazebo Simulation

Control the robot inside Gazebo and view what it sees in RViz using the following launch file:

ros2 launch my_robot_bringup my_robot_gazebo.launch.xml

This will launch the default test world test_world.world.

To actuate the arm use the following command:

ros2 topic pub -1 /set_joint_trajectory trajectory_msgs/msg/JointTrajectory '{header:{frame_id: base_footprint}, joint_names: [arm_base_forearm_joint, forearm_hand_joint],points: [ {positions: {0.3, 0.4}} ]}'

Change positions as required.

To move the mobile base use the following command:

ros2 topic pub /cmd_vel geometry_msgs/msg/Twist "{linear: {x: 0.2}}"

Set desired velocity in the x-axis.

RViz

View just the robot in RViz.

ros2 launch my_robot_description display.launch.xml

TF's

The tf system in ROS 2 keeps track of multiple coordinate frames and maintains the relationship between them in a tree structure.

ROS2 Node Graph

The ROS 2 Graph​ is a network of ROS 2 elements processing data together at the same time. It encompasses all executables in nodes and the connections between them.