This is a Gazebo simulation for a 4-wheeled robot that follows a white ball kept on a simulated house floor.
Move the ball, and as long as the robot's camera can see the white ball, it will follow along.
cd ~/catkin_ws/
catkin_make
source devel/setup.bash
roslaunch my_robot world.launch
Open another terminal:
cd ~/catkin_ws/
source devel/setup.bash
roslaunch ball_chaser ball_chaser.launch
Open yet another terminal:
cd ~/catkin_ws/
source devel/setup.bash
rosrun rqt_image_view rqt_image_view