Carnegie Mellon
Stair Climber - April 2004

It’s been a while since I’ve written because I’ve been very busy. Last Friday, we were given an impromptu design project in Mech E. The assignment was to build a stair climbing machine in a week. We actually only got six days, because it was due this Thursday. It was a purely extra credit assignment, so many people choose not to stress out and didn’t even make an attempt. For climbing one stair, the group would get 5 points on the most recent exam, and an additional point for each stair after that, up to 10 total points. Then, the best few from each recitation would demonstrate in class on Friday in the lecture hall, and the best would get an automatic 100 on one of the first two exams. Scott, Vishesh, and Dan were in my group. We came up with a design that was basically a horizontal tank tread attached to another 45 degrees above the front. The idea is the front tread will lift the front end, while the horizontal tread drives the back in behind. Then, when half of it got above the stair, it would tip forward and move forward to the next stair. We completed it about 10:00 on Wednesday evening, and tried it out on the Donner stairs, but it didn’t work. The horizontal section was a little too short, so as the machine drove forward, the angle it got to was a little too steep, so the center of mass was above the base, preventing it from falling forward. Yesterday, we took it to class, hoping that when the TA saw the design, and how close it got to climbing a stair, he would give us at least a few points. However, the stairs there were a little shorter, so it didn’t get to as high an angle and it was able to tip forward onto the second stair. Unfortunately, it ended up on the second stair at an angle, so it wasn’t able to make it up another. However, if we had been allowed to do multiple runs I think we could have climbed quite a few stairs. After that, we took it to the lecture hall, which we knew had even shorter stairs from the beginning, and it climbed 4 stairs before veering to the right and jamming up against a wall. 5 extra credit points and the knowledge that it could climb some stairs makes me very happy overall with the project.