Bug-0 and Wall-Following Robot Navigation in Gazebo with ROS Noetic

This project demonstrates a robot navigating in a Gazebo environment using the Bug-0 algorithm and a wall-following behavior. The navigation leverages an Action Server for non-blocking communication, allowing the user to cancel the robot's goal anytime. The project also provides the robot's previous goal destination through a service.

Features

• Action Server Navigation: Users can input target coordinates (x, y), and the robot navigates to the location using the Bug-0 and wall-following algorithms.
• Goal Cancellation: The action server allows users to cancel the current goal at any time.
• Service to Retrieve Last Goal: The /lastdestination service returns the most recently set goal coordinates.
• ROS Noetic Compatibility: Built and tested with ROS Noetic and Gazebo.

System Architecture

The system is composed of the following nodes and topics:

• Nodes:
  • /robot_state_publisher: Publishes the robot's joint states.
  • /go_to_point and /wall_follower: Implements the Bug-0 and wall-following algorithms.
  • /bug_action_service: Handles goal management through the Action Server.
  • /userdestination: Service for fetching the last goal set by the user.
• Topics:
  • /cmd_vel: Command velocity to control the robot's motion.
  • /odom: Provides odometry data.
  • /reaching_goal/goal: Sets a new goal for the robot.
  • /reaching_goal/status: Indicates the status of the robot's goal (reached, cancelled, etc.).

Refer to the RQT graph below for a detailed overview of the node connections:

Prerequisites

• ROS Noetic
• Gazebo
• rqt_graph (for visualization)
• Necessary ROS packages for action servers, odometry, and geometry messages.

How to Run

Step 1: Launch the Gazebo Simulation

Run the Gazebo environment with the robot model:

roslaunch assignment1_part2 assignment1.launch

Wait for RViz and Gazebo to start up!

Step 2: Set a Goal

Input the goal coordinates via the terminal:

Set the goal coordinates!
Enter x coordinate: <value>
Enter y coordinate: <value>
Valid coordinate range: x ∈ [-9, 9], y ∈ [-9, 9].

Step 3: Cancel a Goal

While the robot is moving, press q and hit Enter to cancel the current goal.

Step 4: Query the Last Goal

To retrieve the last goal, use the /lastdestination service:

rosservice call /lastdestination