pic: Team 2220's swerve drive!!

[Jedward45]

loading photo ...

[Snalios]

Specs please?

[Tytus Gerrish]

the center of the zero is floating in space

[Alex.q]

Originally Posted by Tytus Gerrish

the center of the zero is floating in space

Thanks for noting that; I believe we had added material there but somehow it didn't get saved...

[bobosalad]

do you guys get parts machined?

[Tristan Lall]

If you haven't already sent it off to be machined, there are a couple things you might want to change.

Firstly, are those recesses in the outer extremities of the frame for the bumpers? (The frame looks like a tall-section C-channel.) If so, that's a bad idea. The bumpers need to be on the frame perimeter, per <R07K>. (As usual, there's some ambiguity as to the precise meaning of that requirement at a formal level, but to err on the safe side, your design probably wouldn't satisfy the rule. That configuration has been allowed in some past years, and disallowed in others—but that's because the rules have been subtly different. Using last year's interpretations as a guide, your design is probably not legal on that count.)

Also, if those recesses are for bumpers, they appear to be a little bit too high. (The bumper zone is between 1 in an 7 in from the floor; since your bumpers are approximately 5 in tall, you need be careful about the top being too high off of the floor.)

As for the lightening triangles, good thinking—but put a big radius (R0.25 in is pretty good, and bigger radii are better in this case) in the corners, for stress relief. This can prevent cracking if the area is subjected to repeated or large stresses. (Also, if it's being machined on a milling machine, there won't really be any simple way to approximate a sharp corner anyway.)

The numerals are cute, but they'll also be invisible behind your bumpers. Lose them—at that size, they're just diminishing the rigidity of your frame members unnecessarily. If you're using them for lightening, try a more conservative pattern of holes or triangles instead.

If you're using a plasma or laser cutter to make the shapes in the aluminum, beware the heat affected zone. (Material properties will diminish in the area of the cuts; the metal will become weaker.) CNC mills, routers and waterjet cutters tend to be nicer for this kind of work.

Are those big pieces of angle (the dark grey ones in the centre) supposed to be steel? If so, why?

[Jedward45]

Originally Posted by Tristan Lall

If you haven't already sent it off to be machined, there are a couple things you might want to change.

Firstly, are those recesses in the outer extremities of the frame for the bumpers? (The frame looks like a tall-section C-channel.) If so, that's a bad idea. The bumpers need to be on the frame perimeter, per <R07K>. (As usual, there's some ambiguity as to the precise meaning of that requirement at a formal level, but to err on the safe side, your design probably wouldn't satisfy the rule. That configuration has been allowed in some past years, and disallowed in others—but that's because the rules have been subtly different. Using last year's interpretations as a guide, your design is probably not legal on that count.)

Also, if those recesses are for bumpers, they appear to be a little bit too high. (The bumper zone is between 1 in an 7 in from the floor; since your bumpers are approximately 5 in tall, you need be careful about the top being too high off of the floor.)

As for the lightening triangles, good thinking—but put a big radius (R0.25 in is pretty good, and bigger radii are better in this case) in the corners, for stress relief. This can prevent cracking if the area is subjected to repeated or large stresses. (Also, if it's being machined on a milling machine, there won't really be any simple way to approximate a sharp corner anyway.)

The numerals are cute, but they'll also be invisible behind your bumpers. Lose them—at that size, they're just diminishing the rigidity of your frame members unnecessarily. If you're using them for lightening, try a more conservative pattern of holes or triangles instead.

If you're using a plasma or laser cutter to make the shapes in the aluminum, beware the heat affected zone. (Material properties will diminish in the area of the cuts; the metal will become weaker.) CNC mills, routers and waterjet cutters tend to be nicer for this kind of work.

Are those big pieces of angle (the dark grey ones in the centre) supposed to be steel? If so, why?

Thanks for the input,
As per the Bumpers, we have been planning from the start to mount about have in, half out, of the C-channel that would normally support it all. Do you think that would mitigate the frame perimeter issue?

Secondly, were using a waterjet for the majority of the cutting, hopefully that should work well...

the parts in the middle are not steel, (mostly for contrast) and while we do have some components that are steel, they're much smaller in size.
Thanks!

[Tom Line]

You absolutely cannot mount your bumpers inside the C-Channel. The bumpers must be mounted to the outside perimeter of your frame, with no indentations or recessing.

You will need to read R07, specifically section K, and understand exactly what the term "Frame Perimeter" means, it is definied on page 9.

By definition, your recessed areas are not exterior vertices. The bumpers may not attach to them or lay against them.

[Andrew Remmers]

Well if you made tabs that supported the bumpers on that outer c channel plane wouldnt that be legal at that point? It supports the bumper down the entire frame perimeter and you can make a bumper "bracket" specifically for mounting the bumpers onto said "channel" as well