CS63 Spring 2004
Lab 6: Robots in Pyro
Due by 11am Friday, April 16

CONTENTS

• Introduction
• Lab Instructions
• What to hand in

• There is a collection of materials available online to help you learn how to control robots with Pyro. Read through the Pyro introduction and focus on the subsections dealing with morphology, effectors, the Pyro interface, sensors, and brains.

• Start the Pyro GUI and load the Stage simulator with the tutorial.world. Select the Player2 robot. Copy the following avoid obstacles brain to your home directory and then load it into Pyro as the current brain. This uses a very simple strategy to try to wander around the environment and avoid obstacles. If it manages to enter the smaller room, it tends to get stuck there. Try to improve this brain so that the robot can more effectively explore the entire environment without getting stuck. Every time you update the brain, press the Reload button in the Pyro GUI.

  #File: Avoid.py
  from pyro.brain import Brain
  
  class AvoidBrain(Brain):
     # Only method you have to define is the step method:
     def step(self):
        Ftolerance = 1.0
        FLtolerance = 1.0
        FRtolerance = 1.0
  
        fleft = self.getRobot().get('range', 'value', 'front-left', 'min')[1]
        fright = self.getRobot().get('range', 'value', 'front-right', 'min')[1]
        front = self.getRobot().get('range', 'value', 'front', 'min')[1]
  
        if (front < Ftolerance):
           print "obstacle front"
           self.getRobot().move(0, 0.2)
        elif (fright < FRtolerance):
           print "obstacle right"
           self.getRobot().move(0, .2)
        elif (fleft < FLtolerance):
           print "obstacle left"
           self.getRobot().move(0, -.2)
        else:
           print "clear"
           self.getRobot().move(0.2, 0)
  
  # -------------------------------------------------------
  # This is the interface for calling from the gui engine.
  # Takes one param (the robot), and returns a Brain object:
  # -------------------------------------------------------
  
  def INIT(engine):
     return AvoidBrain('AvoidBrain', engine)
  

• Now try to create a wall following brain. Ideally we'd like the robot to be able to follow the walls around the entire environment into the small room and back out again. We'd also like the robot to follow as close to the wall as possible without getting stuck. If the robot loses the wall we'd like it to try to recapture the wall as quickly as possible.
• Once your wall following brain is complete, be sure to include a clear explanation of your stragegy in a comment at the top of the file.