pic: FRC 1771 Swerve

[Jimmy Cao]

Looks good!

Just a few things.

For the frame, do you plan on using bumpers? If you look at the Thunderchickens' (217) robot this year, you can see the damage done to their sheetmetal frame where they did not put bumpers. It's not very pretty.

Also, do you support the modules from below the upper frame? If you do not, the load on the main shaft will be very high on one point, and either your frame or the shaft will bend.

It is vital that your main vertical shaft is made of something strong. Very strong. We used 6061 alloy aluminum, 1/8" thick, 1" OD for our first set of modules last year, and those shafts tended to bend, giving us a lot of problems. We later used 2024 alloy aluminum, which worked well. Only problem is 2024 alloy is expensive. This year, we used 1" OD 1/8" thick Chrome-moly steel shaft. It has worked flawlessly.

An issue that we had with a chain based design last year was the difficulty we encountered when trying to remove the modules. If you need to take the modules out often, the chain will get more and more annoying to remove =P

I'm almost sure you accounted for it, but is there a reduction on your CIMs? If not, you'll have one fast robot, that never accelerates.

A few small details. Make sure you leave some way for you to get position feedback on the wheel's position. If you cannot get that feedback, you wont be able to control the beast. After looking carefully at it, I noticed the support on the bottom =P. If I recall properly, it's very similar to the wildstang design. We considered using a similar thing this year, but we were unable to find a "Lazy Susan" of an ideal size. Make sure you can get your hands on all necessary parts.

I'm not a mechanical engineer, so I don't know if this will necessarily be a problem or not, but it seems you did not put any inner support on your frame (in the direction perpendicular to your drive chains). My suspicion is that your frame may have a tendency to give along that axis, if it takes a solid hit. If you use bumpers, remember that you can (and should) use the strength of the wood to your advantage.

Overall, it's a beautiful design. I would love to see it (or an even better version of it) in action next year. Good luck!

EDIT: Just saw the picture of your individual modules. It looks great! I only have a few things to suggest about it.

When using chains (especially ones like your drive chain), it would help greatly if you added a tensioner. It seems you use a 1:1 ration chain stage in your module itself. Adding a tensioner would help (IMO). Also, make sure it is easy to remove the wheels should anything happen. I don't know how that plate on the bottom is attached to the rest of the module, but if it is not easy to remove, it appears to me like you may have difficulties removing the wheel shaft, and the wheel itself. If you can easily remove that bottom plate, then it should be no big deal.

Lastly, it seems like your entire module is highly "modular", in the sense that it can be swapped out for a new one without too much issue. The only thing I see getting in your way may be removing the old one. If you have some way of removing the modules easily (which you may have, and I just cannot see/think of), it would be great.

Again, it's a wonderful looking idea. Good Luck,