Spring2011RobotLabAssignment4

Assignment 4: "Predator vs. Prey"

In this assignment, you will program a multi-robot team of Predators to hunt and capture Prey. You have five Predators (red), who have limited camera sensors and the ability to communicate with each other. Their job is to capture four Prey (blue) after being randomly positioned in the world.

Capturing the Prey

It takes four Predators to capture one Prey. They must position themselves roughly to the North, South, East and West of the Prey. There is a built-in fudge factor for the boxing in of the Prey, so the Predators do not have to be exactly NSEW of the Prey.

Once the Predators have surrounded the Prey, it is considered captured, and it will disappear, and the camera sensors will no longer detect it. Each Predator will also receive a message that a Prey has been captured (with a location). After this message is received, the Predators should move on to find the next Prey.

Once all four Prey have been captured, the Predators should stop (or perform a celebratory dance).

Configuration Files

The configuration files are provided here.

Inside there is a skeleton file Predator.java for the predator. This is the file in which you should program the logic for hunting the prey. There are three additional java files:

• DataChannel.java -- This is a thread that all of the predator and prey register with. It coordinates sending messages between predators and monitors the robots' locations to kill any prey who are captured.

• Prey.java -- This is the logic for the prey. They are not very intelligent, they move at random.

• Driver.java -- This starts all of the robots and the DataChannel object, and connects them to Playerstage. This is the class you should run.

Additional Requirements

• You may not rely on anything particular to the provided map -- The Predators and the Prey will begin in different randomly selected locations every time the simulation is run
• You cannot modify ANY code except in the Predator Agent Implementation (/svn/branches/robot_lab/src/ahoy/agents/predatorimpl.py)

If you are not sure about the above requirements, feel free to email the TA.

Extra Credit

Modify data channel so that there are X seconds of message latency and Y% probability of a message being lost (ie: not delivered). As X and Y increase, do the predators need to adopt a different hunting strategy? Ensure that your new strategy works with X=5 and Y = 25.

Submission

• Submit a tarball to the TA's: Dustin Ingram (dsi23@drexel.edu) & Aaron Rosenfeld (ar374@drexel.edu) containing:
  • Your modified Predator Agent Implementation (/svn/branches/robot_lab/src/ahoy/agents/predatorimpl.py) file
  • A README file briefly describing your work, method, and peculiarities of your program
  • Optional: Any videos or images of your implementation
• If something does not work properly or is incomplete, you must say so in the README.

Grading

The assignment is worth 40 points. Grading will be as follows:

• 40 points : All of the prey are captured within 20 minutes.
• 30-39 points : Some of the prey are captured within 20 minutes.
• 20-29 points : None of the prey are captured within 20 minutes, but the predators come really, really close to capturing them.
• 0-20 points : The predators do not come close to capturing any prey. Anything in this category will probably be closer to 0 than to 20.

The extra-credit is worth up to 10 extra points, depending on how sophisticated the modified approach is.

TOTAL: 40 + 10E.C.

Additional Resources

Although they are probably not necessary for this assignment, if you are interested in this problem, you may enjoy the following research papers:

• Design & Evaluation of Distributed Role Allocation Algorithms in Open Environments
• Multi-Agent Systems in Mobile Ad hoc Networks
• A Study of Multiagent System Operation within Dynamic Ad hoc Networks
• Hungarian Algorithm

Graphics

The Predators are red, the Prey are blue. Green dots signify that a Predator or Prey has been detected by a Predators camera sensor.