Let's Make Robots!


Autonomously navigate a maze
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This robot was built for Autonomous Search & Rescue Challenge proposed by Ro-Bot-X -http://letsmakerobots.com/node/27789.

Robot have to be able to navigate a maze with lanes at least 12" wide, find a toy, grab it somehow and drive out of the maze.

For this I used 2 Sharp IR sensors mounted on left and right side of robot for navigate inside the maze and a home made senzor - 3 photoresistors + 4 high intensity LEDs for detecting the target. I thought, in this way I can differentiate the object (toy) from background (maze walls).

After many hours spent trying to detect the toy in this way, I gave up on this method and choose a more straight one. Navigate the maze and grab anything could be grabbed, in this case, the toy.

So, I switch from gripper to a "device" (the only one came to my mind at 3:00 AM) "equipped" with a velcro collar, the other half of velcro were fitted to the toy. You'll see in the videos and pictures what is about. The width of robot fitted with this thing is 26 cm.

Amazingly, I could not find in my daughter collection a teddy bear to fit my robot, so I pick a fairy.

Maze was built from cardboard, to be easy to pack and deploy, the width of hallways is 36 cm, a little tight as I saw after programming phase began, but in the end was ok.

The search process works in this way:

- robot start navigating the maze and always keep on left side. In this time the "rotor" fitted with velcro is spinning continuously.

- when the toy is touched, the two half of velcro sticks togheter (not every time) and the toy is moved to the rear of robot where close a switch (the same used to start the robot). I hope this is visible on video, I plan anyway to record this process alone for a better view.

- after the switch is closed, the rotor is stopped, robot turns 180 deg. and swich from navigation to left side to navigation to right side and return to the entrance/exit. No path recording or processing is made, yet.

Video of one succesful rescue mission - http://www.youtube.com/watch?v=9IzRfHQMkXM

                                                         - http://www.vimeo.com/29541322

Here is one of the early moments of our journey, where it express its opinion about how the maze should look like. Its behavior had to be polished "a little" - http://www.vimeo.com/29601814