Sorry if anyone was actually following this - I meant to update it a few more times during the 2.007 build season, but with FIRST season mixed in there too I have been remiss.
WEEK 12
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We are now three weeks away from impound (the 2.007 equivelent of ship date), and the pressure is on to get all modules tested and integrated. The lab is an incredibly busy place these days as people finish all their machining.
I settled pretty early on a tread-driven bot that can climb straight down the ramp sides instead of following a zig-zag path. Since we are only allowed to use the raw materials from the kit, I made the treads out of strips of rubber. At first, there was more friction between the belt and the ground than between the belt and the crowned wheels that hold it in place. The rectify this, I wrapped the outside of the belt in electrical tape (no rule against tape in 2.007). This solved the problem and the result was a very mobile, quick, and robust drive-train than can go from the top level to the bottom level in less than 10 seconds.
I am currently working on the ball collection roller. It is a simple paddle-wheel design than I may convert to something more compliant if it jams to much. I should be finished with all the machining by the end of the week and that will leave me two weeks to tweaking, practicing, and of course non-functionally decorationg.
Here is a CAD render of the current design (minus the treads):
The variety of robot designs is amazing, as the rules are somewhat more lax than FIRST. Things can detach, tether bots are allowed, size and weight limits are not very constraining. Mainly, though, robots fall into a few drive-train categories from what I can see. The most interesting are the ones that stay stationary or minimally mobile on the top shelf, simply grabbing balls and rolling or shooting them to the bins. Done well, this could be a very consistent scoring mechanism and hard to beat. A large handful of other robots are taking the direct path down. Most get over the steps with 4WD and large wheels. Some have treads. The third group are the 2WD robots that will most likely be taking the zig-zag route. Ball collection mechamisms vary greatly too. A lot of passive one-way gates. Several shovels. Active rollers/paddle-wheels make up most of the rest.
Even among the FIRST alumni that I know in the class, there are three very different designs. My tank-inspired stair climber is the simplest. There is a very effective top herder that isolates the balls quickly and drops them down a ramp. The third is an ambitious omni-drive chassis with 6 wheels driven by thee motors, one with a differential. (From only the materials in the kit, this is a very impressive feat. Everything is "home-made.") It may or may not score balls.
I'll try to take some pictures this week as people's designs start coming together.