Shimmy Bot

Here is our team's first robot success story, Shimmy Bot. Shimmy Bot was designed to traverse a right-angled figure-8 shaped path and return exactly to its point of origin. This was the first challenge. This may sound simple. However, "No two motors are created equal" was a caution we took to heart. With a couple of motors that are not precisely equal in power, even to a minute degree, traveling straight lines and making good 90-degree turns left and right is very difficult. To counter the inequality of motors, we designed a robot which triggered a couple of touch sensors via a piston per every few rotations of the wheels.

Good concept, yes? We thought so, too. However, the constraints of our programming environment and the v1.0 Lego Brick we were programming meant we could only consistently count one wheel at a time. So we did. Only one wheel would move at a time. This resulted in our robot doing this funny little "shimmy dance" as it walked the figure-8 course path. It was a smashing success and hilarious to watch. Unfortunately, we didn't get a video of shimmy bot before we had to take him apart for the next challenge. Click here for a copy of our lab report.

Elevator Bot

Elevator Bot was another robot we built for the figure-8 challenge. We already had Shimmy Bot for the grade, but we decided to build Elevator Bot "just for giggles" to see if the concept could work. As noted above, inequality of engines was a problem. The only way to absolutely guarantee a straight line was to have only ONE motor controlling all forward and backward motion of the robot, no turning considered. That left the question of how to rotate the robot for the 90-degree turns. We conceived of a robot that lowered a piston beneath it, raising the robot, and then rotating around that piston a desired angle.

Good concept, yes? We thought so, too. That's why we built it. As stated, one motor handles the forward and backward motion of the robot. Another motor is responsible for the masterfully geared-down elevating piston that raises the robot wheels off the ground. The third and final motor was responsible for rotating the robot once the piston had fully lowered, lining up the rotation gears. Seeing as how we already had Shimmy Bot, we included Elevator Bot as an honorable mention in our lab report for Challenge 1. Elevator Bot is still in one piece, so a video may be forthcoming.

Dragon Bot

Dragon Bot was the robot we constructed for Challenge 2. Challenge 2 was to traverse a large rectangular field with a white surface and blue cross hairs to seek out orange blocks. The orange blocks had to be located, picked up by the robot, and then taken to a green bin in the center of the field where the robot must drop the block. Again, this may sound easy, but I kid you not, it was very very difficult. We named him Dragon Bot because the design made the robot look like a dragon. We even put on little orange wings for fun.

As per Dr. Potter's advice, we decided that we would solve most of the challenge problems in the design phase, choosing to NOT rely on the software to resolve issues. The first issue was that we had a constraint of only three motors. But we had four kinetic tasks to perform! We had to work the left-side treads, the right-side treads, the grabbing of the block, and the lifting of the block to get it into the bin. Early on, it was decided that motors would share tasks: motor A would control the left-side tread and the claw, motor B would control the right-side motor and the lifting of the arm, and motor C would cycle between the two sets of tasks: grabbing a block and moving the robot. Dragon Bot was built on this concept.

Our robot was purely reactive, utilizing a quadrant by quadrant "bouncing" search of the challenge field. When searching a quadrant, we bounce off the blue lines, we bounce off the borders, and we bounce off the green bin. When we find a block, we pick it up, dump it, and move on to the next quadrant. If no block is found within 13 bounces, we assume there is no block and move onto the next quadrant. The in's and out's of the design and programming stages are extensive. Everything is specified here in our lab report. Also, we have a very entertaining video of one of the successful runs of Dragon Bot. Please excuse the poor video quality and the power chord attached. Our batteries were dead. Also, please excuse the idle conversation. We're nerds.