farm_bot

A ROS 2 package for a farm robot simulated in Gazebo (Ignition). The robot drives through a farm world and uses LiDAR-based obstacle avoidance to move around obstacles.

Features

• Farm world simulation in Gazebo (worlds/farm_world.sdf)
• Robot model defined with xacro (urdf/farm_bot.xacro)
• Reactive obstacle avoidance using LiDAR scan data (farm_bot/obstacle_avoidance.py)
• Single launch file that starts the simulation, robot, bridges, and controller

Requirements

• ROS 2 (Humble or newer) on Ubuntu 22.04
• Gazebo (Ignition / ros_gz)
• Python packages: rclpy, xacro
• ROS packages: robot_state_publisher, ros_gz_sim, ros_gz_bridge, sensor_msgs, geometry_msgs

Installation

Create a colcon workspace and clone the repo into its src folder:

mkdir -p ~/farm_ws/src
cd ~/farm_ws/src
git clone https://github.com/Rosemar4/farm_bot.git

Install dependencies from the workspace root:

cd ~/farm_ws
rosdep install --from-paths src --ignore-src -r -y

Build the package:

colcon build --packages-select farm_bot
source install/setup.bash

Usage

Launch the simulation, robot, and obstacle avoidance node:

ros2 launch farm_bot farm_bot.launch.py

The robot starts at (0, 0, 0.2) and moves forward until it detects an obstacle within 1.0 m in front of it, then turns toward the side with more open space.

Package Structure

Parameters

Tunable values are set in farm_bot/obstacle_avoidance.py:

Parameter	Default	Description
safe_distance	1.0 m	Distance at which the robot stops/turns
linear_speed	0.5 m/s	Forward speed when the path is clear
angular_speed	0.8 rad/s	Turning speed when avoiding an obstacle

Troubleshooting

• Package 'farm_bot' not found: run source install/setup.bash after building.
• No /scan data: check that the LiDAR is defined in farm_bot.xacro and that the bridge is running (ros2 topic list).
• Robot doesn't move: confirm /cmd_vel is bridged with ros2 topic echo /cmd_vel.

License

Apache License 2.0. See setup.py for details.

Maintainer

Rosemary Ojoawo (rbojoawo@student.lautech.edu.ng)