zinger_nav

Defines the ROS2 Nav and SLAM setups for the zinger 4 wheel steering robot

Dependencies

The configurations in this repository assume you have the following prerequisites installed on the device on which you want to run this code. That device might be an Ubuntu machine or a physical robot using Raspberry Pi OS.

1. ROS humble with the robot_state_publisher, the joint_state_broadcaster and the ros_control packages.
2. A working ROS workspace.

Also the following packages should be present:

1. zinger_description - Contains the geometric description of the Zinger robot for ROS to work with.
2. zinger_swerve_controller - Contains the controller for the Zinger robot to control the 4 wheel steering.

Contents

This repository contains different folders for the different parts of the navigation and SLAM configuration for the zinger robot.

• The config files that provide the configurations for the navigation and the SLAM stacks.
  • config/nav2.yaml defines the settings for the Nav2 stack.
  • config/slam.yaml defines the settings for the SLAM stack.
• The launch directory contains the launch files
  • launch/nav2.launch.py launches the Nav2 stack.
  • launch/slam.launch.py launches the SLAM stack.

Configurations

Nav2 configuration

The Nav2 configuration is based on the nav2_bringup package. The configuration file is located in the config directory and is called nav2.yaml. The Nav2 stack is configured with:

• SmacPlannerLattice as the global planner, or planner in Nav2 terms. The standard values for the parameters for the SmacPlannerLattice are used.
• MPPIController as the local planner, or controller in Nav2 terms. The standard values for the parameters for the MPPIController are used, except that some values were adjusted to match the capabilities of the robot.

SLAM configuration

The SLAM configuration is based on the slam_toolbox package. The configuration file is located in the config directory and is called slam.yaml. The configuration file uses the standard configurations from the slam_toolbox package.

Usage

The zinger_nav contains two different launch files that each can be launched either in the Gazebo simulator or in the real world on a physical robot. In order to launch either the SLAM stack or the navigation stack you will need to have both the robot description loaded and the zinger_swerve_controller package running. When running in a simulation in Gazebo you can start these two by running the following commands in two different terminals.

ros2 launch zinger_ignition ignition_launch rviz:=true world:=empty_world

ros2 launch zinger_swerve_controller swerve_controller.launch.py use_sim_time:=true

If you are running on a physical robot you will need to launch as follows:

ros2 launch zinger_description robot_description use_fake_hardware:=false

ros2 launch zinger_swerve_controller swerve_controller.launch.py use_sim_time:=false

Launch the navigation stack

To launch the navigation stack in the Gazebo

ros2 launch zinger_nav nav2.launch.py use_sim_time:=true

When launching the navigation stack on a physical robot use

ros2 launch zinger_nav nav2.launch.py

Launch the SLAM stack

In order to launch the SLAM stack in the Gazebo simulator use

ros2 launch zinger_nav slam.launch.py use_sim_time:=true

When launching the SLAM stack on a physical robot use

ros2 launch zinger_nav slam.launch.py

Notes

When using RViz to visualize the robot and the navigation stack, make sure to set the fixed frame to map, otherwise there will be no navigation information available.