Sup everybody. This is my second year as a mentor for VRC teams, and my first year where I’m seriously involved from the start. The last time I really competed in a VEX based competition, it was still the FIRST sponsored FIRST Tech / VEX Challenge. Since then, there have been a lot of new products and a lot of innovation in the Vex competition universe. While I’ve seen the occasional reveal video and even attended a competition last year, I’m out of the loop quite a bit and have some catching up to do.
As VEX goes on for many years, designs generally converge into some “standard” shapes and layouts. I’m really curious as to what the most common drivetrains, chassises, and arm towers look like these days. This is a good opportunity for you to post pictures of your favorite robots from old arm games, or maybe your current drive chassis, if you want to brag and you feel your design is a pretty good representation of the community standard.
Some specific questions:
- How many motors on drive / how do you gear? My back of the napkin math seems to suggest with 4" wheels, you can do pretty well with four motors, driving the wheels with the “high speed” (160 RPM) gearing, 1:1. I think this is what my team did last year. Any reason to deviate?
- 4" Omni Wheels are still the standard, even for tank drives, right? Any advantage to 6 vs 4 wheels?
- C-Channel - flanges in or flanges out? A little of both?
- How do you connect your two drive halves together? Back in 2006-2007, you’d use angle pieces bridging all four pieces. I’ve seen different setups recently. How much structure do you really need to connect these?
- Arm towers - How do you rigidly mount your uprights to the chassis? Particularly if there isn’t a convenient flat surface without flanges to mount those pieces to? Angle pieces again are what come to mind, with some diagonal support.
- Is EVERY piece of a highly competitive robot aluminum? Just the stuff above the drivetrain? Just the stuff you need to be super light?
I know this is a lot of questions, but any help would be appreciated while I get up to speed and try to get my teams to be competitive. I have some ideas on how to do all of these but I could use a second (or third, or fourth…) opinion.