otto_gazebo

This package simulates a x-drive robot (Otto) using Gazebo Harmonic + ROS2 Jazzy Jalisco. Also contains configuration files for tele-op controllers, the omni wheel drive controller, AMCL launch + parameter file, and Navigation2 parameters. Works together with the otto_bringup and otto_description packages, which can be found in the Autonomous-VEXU/otto_bringup and Autonomous-VEXU/otto_description repositories.

Table of Contents:

• ROS Package Dependencies
• Demo Instructions
• File Structure + Organization
• Launch Files
  • nav2_test_world.launch.py
  • nav2.launch.py
  • spawn_robot.launch.py
  • localization.launch.py
• Nodes
  • localize.py
• Resources + Docs

Demo Instructions

Example of things that can be done with the launch files in this package:

Nav2 in the base turtlebot3_world:

Terminal 1: ros2 launch otto_gazebo nav2_test_world.launch.py
Terminal 2: ros2 launch otto_gazebo nav2.launch.py

Tele-op Control:

Terminal 1: ros2 launch pushback_sim world_select.launch.py world:=<world_name>
Terminal 2: ros2 launch otto_gazebo spawn_robot.launch.py
Terminal 3: ros2 launch otto_bringup controller.launch.py

Localizing with AMCL on the VEX field:

Terminal 1: ros2 launch pushback_sim world_select.launch.py world:=<world_name>
Terminal 2: ros2 launch otto_gazebo localization.launch.py

Note: Do not forget to build the workspace by running colcon build --symlink-install and then source install/setup.bash inside of the workspace directory

File Structure + Organization:

otto_gazebo/
├── config/
│   ├── amcl.yaml
│   ├── nav2.yaml
│   ├── omni_wheel_params.yaml
│   ├── robot_bridge.yaml
│   └── robot_lite_bridge.yaml
├── launch/
│   ├── controller.launch.py
│   ├── nav2_test_world.launch.py
│   ├── nav2.launch.py
│   └── spawn_robot.launch.py
├── robot/
│   ├── otto_lite.urdf.xacro
│   └── otto.urdf.xacro
├── rviz/
│   └── amcl_test.rviz
├── src/
│   └── localize.py
├── CMakeLists.txt
└── package.xml

Launch Files

Moderately detailed descriptions about what each launch file does and its arguments plus which outside packages it references/uses.

nav2_test_world.launch.py

Launches the demo world from the turtlebot3_gazebo package with Otto spawned in at x = 0.5, y = 0.5.

There are no launch arguments for this launch file!

nav2.launch.py

Launches the main bringup node + Rviz for Navigation 2, should be used with nav2_test_world.launch.py

map: `package://turtlebot3_navigation2/map/map.yaml' # map file path for the world that is being used
params_file: `package://otto_gazebo/config/nav2.yaml' # params file that should be used
use_sim_time: true # toggle for using sim time (gz sim /clock) or not

spawn_robot.launch.py

Spawns the robot into a pre-existing Gazebo Sim world

x_pose: 0 # x coordinate will the robot will spawn
y_pose: 0 # y coordinate will the robot will spawn
robot_lite: True # if true, will spawn the URDF model that has a better RTK

localization.launch.py

Starts AMCL + map server components of Nav2, also launches localize.py node to make the robot spin in place

use_sim_time: True # toggle for using sim time (gz sim /clock) or not
map: 'pushback_sim/maps/vax_field_map.yaml' # the file path to the map the map_server will use
amcl_config: 'otto_gazebo/config/amcl.yaml' # configuration file to use for amcl node
rviz_config: 'otto_gazebo/config/amcl_test.yaml' # configuration file to use for Rviz2 node

Nodes

A few helper nodes that make testing more efficient.

localize.py

A python node that simply spins the robot in place, calls the two main AMCL services /request_nomotion_update and /reinitalize_global_localization, while publishing the average covariance from topic /amcl_pose in a more readable format

this node can be found in the localization.launch.py launch file

Resources + Documentation:

Various links to docs that I thought were useful. YouTube is also a pretty good resource as there are a lot of robotics channels that cover ROS2 concepts and have Gazebo Sim tutorials.

ROS2 Documentation + Resources:

ROS2 Documentation (Jazzy Jalisco)
Open Robotics Discourse
Robotics Stack Exchange

Core Packages + Software Documentation

Nav2 Documentation
Gazebo Harmonic Documentation

Other Resources and Links:

Inertia Matrix Calculator: cylinder/wheels
Inertia Matrix Calculator: rectangle/chassis