Robotics_Go_Chase_It

Project #2 Go Chase It! for Robotics Software Engineer Nanodegree Program

Overview

In this project, I created two ROS packages: my_robot and ball_chaser that will be used on Gazebo. The my_robot package includes the design of the robot, which also includes the differential drive, lidar & camera sensors, and the gazebo world the robot lives in. The ball_chaser package contains two C++ ROS nodes that interact with the robot and makes it chase after a white-colored ball.

C++ ROS Nodes Description

1. drive_bot:

• A server node that will provide a ball_chaser/command_robot ROS service to drive the robot around by controlling its linear x and angular z velocities
• The service publishes a message containing the velocities to the wheel joints

2. process_image:

• A client node that subscribes to the robot's camera images and analyze them to determine the position of the white ball
• Upon determining the position, the client node requests a service from the drive_bot server node to drive toward the ball

Requirements

• Gazebo any version later than v7.0.0
• ROS Kinetic -follow instructions here: ROS Installation Instructions
• GNU make
  • Installation for Windows
  • Installation for Mac
  • make is installed by default for most Linux distros
• C++11 Complier (gcc/g++)

Recommended Virtual Machine Alternative Specs:

• Ubuntu 64-bit Disk Image
• 2 GB of RAM
• 20 GB Disk Space
• 4 Logical Cores

Setup

1. After installing and meeting the requirements listed above, open up a terminal.
2. Create and initialize a catkin workspace:

    $ mkdir -p /home/workspace/catkin_ws/src
    $ cd /home/workspace/catkin_ws/src
    $ catkin_init_workspace

3. Clone the project repository & move the my_robot and ball_chaser directories into the src directory:

    $ cd /home/workspace/catkin_ws/src
    $ git clone https://github.com/jordanjj8/Robotics_Go_Chase_It.git
    $ mv Robotics_Go_Chase_It/ball_chaser /home/workspace/catkin_ws/src/ball_chaser 
    $ mv Robotics_Go_Chase_It/my_robot /home/workspace/catkin_ws/src/my_robot
    $ rm -rf Robotics_Go_Chase_It

4. Navigate back to the catkin workspace and build the executables:

    $ cd /home/workspace/catkin_ws/
    $ catkin_make

5. Source the setup script and launch the launch file. The robot in Gazebo should open up:

    $ cd /home/workspace/catkin_ws/
    $ source devel/setup.bash
    $ roslaunch my_robot world.launch 

6. Now open up another terminal and launch the ball_chaser package. This will enable the robot to chase after the white ball:

    $ cd /home/workspace/catkin_ws/
    $ source devel/setup.bash
    $ roslaunch ball_chaser ball_chaser.launch