Autonomous Navigation with SLAM

Overview

Now, the navigation stack will kick in and guide HomeR to its goal. It plans a trajectory from HomeR’s current pose to its goal pose. It monitors HomeR’s status (pose and velocity) and gives out advice of velocity command (cmd_vel) to keep the robot on track. ROS2 uses a collection of pakcages from navigation2 framework to navigate all kinds of robots. Refer to the First-Time Robot Setup Guide for a more systematic introduction.

Requirements

slam_toolbox is still required, so that the map will be served and HomeR gets localized in it.

navigation2 and nav2_bringup will make the HomeR’s dream of autonomous navigation come true.

Install dependencies in terminal.

$ sudo apt install ros-jazzy-navigation2 ros-jazzy-nav2-bringup

Configure Map Path (on Host)

Use whatever text editor (VSCode below) to open the configuration file for slam_toolbox

$ code $HOME/homer_ws/src/homer_control/configs/localization_params.yaml

Change line 18 to set map_file_name parameter to the path of the map which you’ve saved in the SLAM: Simultaneous Localization and Mapping guide.

map_file_name: /your/map/file/path/

Build homer_control package afterwards.

$ cd ~/homer_ws/
$ colcon build --packages-select homer_control

Bring Up the HomeR Driver Interface (on RPi)

$ ros2 launch homer_control bringup_homer.launch.py

Set Goal Pose (on Host)

(Optional) Correct initial pose

It is possible that HomeR not start at the same pose as the mapping stage. In this case, you’ll need to manually set HomeR’s pose using the 2D Pose Estimate tool from Rviz. Find it in the Tools panel (usually on top of the window). Observe the true pose of the robot. Click 2D Pose Estimate button. Click and hold left mouse button at the location in the map you think the robot is at. Rotate the green arrow, until you think it is pointing to the robots heading direction.

Set goal pose

Find 2D Goal Pose button in the Tools panel. Click the button. Click and hold left mouse button at the location in the map you want to send the robot to. Rotate the green arrow, until you think it is pointing to the robot’s end heading direction.

Refer to the example below: