Angry Turtle

ros-turtlesim-controller

First assignment for Robotics course @ USI 19/20.

Contributors

Giorgia Adorni - giorgia.adorni@usi.ch

GiorgiaAuroraAdorni

Brief

A simple node that controls a turtle in turtlesim:

• the turtle is able to write 'USI'
• when any other turtle gets closer than 2 meters to it at any given time, the turtle becomes angry, stops writing and starts pursuing the offender.
• the offensive turtles are managed in another thread: they are spawned in a random position and move randomly (it is possible to control this turtle using the turtle_teleop_key from the turtlesim package)
• the angry turtle does not aim directly towards its target, but instead tries to look ahead m meters in front of the offender to intercept it and then eliminate it.
• after the elimination of the offender, the angry turtle moves back to the initial position and restarts its writing behavior, ignoring anyother turtle on the way back.
• when all the turtles have been killed, the angry turtle writes 'USI' for the last time.

Prerequisites

• Python 2.0
• ROS
• Turtlesim

Installation

Clone the repository

$ cd ~/catkin_ws/src
$ git clone https://github.com/GiorgiaAuroraAdorni/ros-turtlesim-controller

build ROS packages and update the environment

$ catkin build
$ re.

Usage

The execution can be started simply using the following command:

$ roslaunch usi_angry_turtle angry_turtle.launch

The file angry_turtle.launch is a launch file that contains the instruction to configure the two nodes required: the turtlesim_node and the node angry_turtle_controller.py that contains the implemented controller.

Alternatively, it is possible to start the simulation as follows:

• in the first command line window type:

  $ roscore 

• in another terminal, to launch turtlesime, type:

  $ rosrun turtlesim turtlesim_node
  

• in the last window, to start the program, type:

  $ rosrun usi_angry_turtle angry_turtle_controller.py
  

Alternatively, it is possible to control a turtle using the turtle_teleop_key. In this case it this necessary to spawn another turtle and type in another window

$ rosrun turtlesim turtle_teleop_key /turtle1/cmd_vel:=/turtleTarget/cmd_vel

where turtle1 is the angry turtle and turtleTarget is the offender.