Simple Line Follower

About

This repository demonstrates a basic line-following robot which uses a Proportional-Derivative Controller.

This ROS 2 package is used to demonstrate these examples :

Code which is tough to test (Ex : naive_line_follower.cpp)
Code which is easy to test (Ex : line_follower.cpp)
Basic unit-tests taking the line follower as an example (Ex : test_line_follower_basic.cpp)
Basic unit-tests taking the naive line follower as an example (Ex : test_naive_line_follower.cpp)
Good unit tests taking the line follower as an example (Ex : test_line_follower_good.cpp)

Dependencies

Ubuntu 22.04
ROS 2 Humble
Ignition Gazebo(Fortress)
bcr_bot

Installation

Clone this repository

git clone git@github.com:ggupta9777/simple_line_follower.git

Clone bcr_bot

git clone git@github.com:blackcoffeerobotics/bcr_bot.git

Install dependencies using rosdep:

rosdep install --from-paths src -y --ignore-src

Build the packages with test config(Note : The `--cmake-args`` used above are to enable code coverage analysis)

colcon build --symlink-install --cmake-args -DCMAKE_BUILD_TYPE=Debug   -DCMAKE_CXX_FLAGS="--coverage" -DCMAKE_CXX_OUTPUT_EXTENSION_REPLACE=ON

Run instructions

Launch bcr_bot

ros2 launch bcr_bot gz.launch.py \
    camera_enabled:=True \
    stereo_camera_enabled:=False \
    two_d_lidar_enabled:=True \
    position_x:=0.0 \
    position_y:=0.0  \
    orientation_yaw:=0.0 \
    odometry_source:=world \
    world_file:=empty.sdf

Run the line follower node

Run the line_follower_node

ros2 run simple_line_follower line_follower_node --ros-args --params-file src/simple_line_follower/config/params.yaml

Run the naive_line_follower_node

ros2 run simple_line_follower naive_line_follower_node --ros-args --params-file src/simple_line_follower/config/params.yaml

Running Tests

Run the test scripts(Note : The --event-handler=console_direct+ argument is used to show the logs of the testing process)
```
  colcon test --event-handler=console_direct+
```

Generate Code Coverage

Use lcov to generate code coverage

lcov --capture --directory build/ --output-file code_coverage_report.info

Generate an HTML file to showcase the code coverage report

genhtml code_coverage_report.info --output-directory html_code_coverage_report

Open the code coverage on your browser

sensible-browser html_code_coverage_report/index.html

Topics

/bcr_bot/cmd_vel : This topic is used to publish velocity messages to the bot in Gazebo
/bcr_bot/odom : This topic is used to obtain odometry information regarding the bot

Demo

This is a demo of the bot following a line defined by the waypoints : (0, 1, 0) and (5, 1, 0)