CHRISLab Turtlebot2 System

Introduction

Custom models and launch setup for CHRISLab Kobuki-based Turtlebot 2 system.

This repository contains code that interfaces with the ROS 2 versions of the Kobuki Turtlebot2 models.

Installation and Setup

This package has a number of dependencies.

We will add a number of repos to our setup and install.

Quickly skim this README before installing or running anything:

This demonstration makes use of the following repositories:

- git: {local-name: src/chris_ros_turtlebot2,     uri: 'https://github.com/CNURobotics/chris_ros_turtlebot2.git',     version: ros2-devel }

At this current stage, some Kobuki Turtlebot2 related packages are not released in ROS2 binary form, so we are using the following:

https://github.com/stonier/ecl_core.git                  devel
https://github.com/stonier/ecl_lite.git                  devel
https://github.com/stonier/ecl_tools.git                 devel
https://github.com/stonier/sophus.git                    release/1.2.x
https://github.com/kobuki-base/kobuki_core.git           devel
https://github.com/kobuki-base/kobuki_ros.git            devel
https://github.com/kobuki-base/kobuki_ros_interfaces.git devel

Install in the src folder of your WORKSPACE_ROOT, and from the

colcon build
. setup.bash

NOTE: Anytime you build new packages, you need to re-run the setup.bash script inside the workspace root.
Anytime you change a Python script or launch file, you need to re-run colcon build from the WORKSPACE_ROOT folder, but you only need to re-source . setup.bash when the package information and folders change.

Operation

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Start the hardware

sudo chmod a+rw /dev/ttyACM0

• This allows for the Hokuyo LiDAR on the Turtlebot2 to get LiDAR data
• Best to set this using a udev.rule (Google)

ros2 launch chris_ros_turtlebot2 turtlebot_bringup.launch.py

• Starts the hardware on the Turtlebot2

ros2 launch chris_ros_turtlebot2 astra_bringup.launch.py use_sim_time:=False

NOTE: The below launch files are configured to default to use_sim_time:=True For each , add the option to set use_sim_time:=False. The on robot setup, has been modified to do this for you.

NOTE: There is option for Kinect launch, but that camera is not working under Ubuntu 22.04 and ROS 2 Humble

or

Start Gazebo with the desired world model.

• See chris_world_models repository for some available options

  • e.g. ros2 launch chris_world_models gazebo_creech_world.launch.py

  • Start the simulated robot

    • ros2 launch chris_ros_turtlebot2 turtlebot_gazebo.launch.py
    • Starts the simulated Kobuki Turtlebot2 in Gazebo with the CHRISLab sensor configuration

Optional: Explore URDF

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The robot_description is an XML-file used to describe the robot model. This is loaded by the launch of the robot.

Our CHRISLab robot uses a Hokuyo URG-04 single plane laser scanner and a Orbec Astra camera.

The model separates the physical properties and visual properties. A collision definition is used to model shapes that interact, while visual define colors and textures that are shown in 3D view. The physics is governed by the inertial properties (e.g. mass and intertia about different axes). The movements are governed by joints that define axes of movement between links and any friction modeled by damping.

This robot_description is used by RViz for viewing robot, Gazebo for physics based simulations, and for collision checking in planners.

See http://gazebosim.org/tutorials/?tut=ros_urdf for a discussion of URDF in Gazebo

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