Automated Guided Vehicles

Our fourth project was to build and program an automated guided vehicle. Here are the requirements and restrictions:

1. Design a Lego Robot to safely transport, without damage, 2 ping-pong balls and a golf-ball from the top of a platform to a box separated by a given distance d.

2. The outside dimensions of the flat platform are L30xW10 cm and it is constructed from 1/4² grade plywood. The balls initially rest in three 1cm. diameter holes that are 5 cm apart on the platform. The outside dimensions of the disposal box where the ping-pong balls need to be transported into are approximately L35xW18xH18 cm.

4. The Lego Robot must fit within the 20x20x20 cm box.

5. The design objective is to pick up and deliver the balls within the shortest amount of time. Your robot should follow a 2 cm wide black line on the white laminate floor going from the center of the platform to the center of the disposal box. The line will NOT be a straight and will contain 4 T-junctions, two leading to wrong direction and two leading back to finishing platform. Your robot should not get confused about the line while navigating over these junctions. In addition, there will be two extra challenges. First one is a semi-cylindrical bump with L20xW10xH5 cm dimensions located somewhere along the path, and your robot must navigate over it. The second one is a wooden block with L35xw18xH18 cm dimensions located somewhere along the path, and your robot needs to navigate around it. The exact location of these obstacles will not be given until the project demonstration time.

6. Initially, your robot should not be in contact with the pig-pong and golf balls, you can start at any position on or around the flat finishing platform.

7. Once the robot is positioned and in place in front of the platform, a start signal will be given and the robot must deliver the balls from the platform to the box within 3 minutes. The transport time will be measured from the start signal to when the last ball is dropped to the box. Once the robot is started, no external communication, interaction, or influence of any kind is allowed - the robot must be completely autonomous.

8. The projects will be ranked according to their travel time (shortest time will take the first place). The performance scores will be assigned will be proportional to travel time. In addition, below penalty scores will be assessed if you fail one of the objectives.
- Failing to deliver a ping-pong ball, 15 pts each
- Failing to deliver the golf-ball, 20 pts
- Failing to go over the bump, 10 pt
- Failing to navigate around the obstacle, 15 pts.

This project was very difficult. It challenged us to the max. Again our first objective was to design a robot that could pick up two ping pong balls and a golf ball all at once. Our robot could have easily gone across the bump. It had a motion sensor in place to detect an obstacle, but we did not know how to distinguish from the box and an obstacle so we decided to develop two different programs to avoid the obstacle altogether.





Here is Brandon Hahn fixing our robot in frustration after it broke apart while adding more pieces to it.



While programming our robot we came across many problems. We had a tough time mounting our motor to pick up the balls but finally we found away to do so. Our next task was to get it to follow the black lines. This was very tricky. We tried using the program from the cd program but for some reason it would not work with our robot. So we were unable to get our robot to follow the black line. Here is our final robot.



After we built our robot and knew that we were unable to follow the black line, we set out to obtain the most points possible. We were going to go straight to the delivery box and deliver all three boxes. There lied a problem though, our motors were not callibrated correctly and our robot could not even make a straight line. So we abandoned that idea and did the best we could.

We ended up being able to pick up all three balls and follow the black line for a little bit but this project ended up being more than we could handle.