Description of the Project:

This project educates to implement a Bug2 Motion planner Algorithm using Extented Kalman filter state estimation. Algorithm in a nutshell:

• Initially, the TB4 heads towards goal on the sg-line (A line between start and goal points)
• If an obstacle/wall is on the way, follow it until you encounter the sg-line closer to the goal.
• Consider the point where turtlebot4 reaches the sg-line first as reach point. Similarly, consider the point where turtlebot4 leaves the sg-lines as leave point
• Once the TB4 reaches the leave point on the sg-line, TB4 leaves the obstacle/wall and continues toward the goal

Instructions to run the Project:

Create a ROS2 Workspace

cd
mkdir workspace

Create a sub-directory with src and colcon build your workspace

cd workspace
mkdir src
colcon build

Clone the Turtlebot4Lessons Repository into src folder

cd workspace/src/
git clone https://github.com/turtlebot/TurtleBot4Lessons.git

View your Source files

cd Turtlebot4Lessons

Instructions to setup Turtlebot4 Simulation source installation and Motion Planner project

TurtleBot4 Simulation Source installation

To manually install TurtleBot4 simulation from source, clone the git repository:

cd ~/workspace/src
git clone https://github.com/turtlebot/turtlebot4_simulator.git

Install dependencies:

cd ~/workspace
vcs import src < src/turtlebot4_simulator/dependencies.repos
rosdep install --from-path src -yi

Build the TurtleBot4 simulation package:

. install/setup.bash
colcon build --symlink-install

Now, download your custom world inside below directory

cd ~/workspace/src/turtlebot4_simulator/turtlebot4_ignition_bringup/worlds
wget https://raw.githubusercontent.com/sumedhreddy90/TurtleBot4Lessons/ROS2-visual-Nav/projects/unit02_simulation_motion_planner/worlds/bug2_world.sdf

Edit ‘world’ DeclareLaunchArgument in ignition.launch.py

cd ~/workspace/src/turtlebot4_simulator/turtlebot4_ignition_bringup/launch/
gedit ignition.launch.py
goto line 65 and change default_value='bug2_world'

Launch Turtlebot4 in Ignition Gazebo

To launch the TB4 onto custom world run below launch command:

ros2 launch unit02_simulation_motion_planner tb4_ignition.launch.py

To undock the Turtlebot4 from the Charging Dock

Execute below launch command in your terminal for undocking Turtlebot4

ros2 launch unit02_simulation_motion_planner tb4_undock.launch.py 

To launch motion planner alogirthm for a given goal position

ros2 launch unit02_simulation_motion_planner tb4_bug2.launch.py

Default goal location is set to X: 8.0 Y: 10.0

To pass goal postion from command line

ros2 launch unit02_simulation_motion_planner tb4_bug2.launch.py 'my_goal_pose:=[2.0, 10.0, 0.0, 0.0, 0.0, 0.0, 0.0]'