New Antweight

do you think you'll be ready for the metrocon event in Tampa July 7th?

Nope, not even close. Don't have enough time to do all the machining (and soldering) between now and then, and I'm still waiting on the custom magnets for the weapon's integrated motor. It'll be up and running by the end of July.

I think that Metrocon is around the 23rd???

maybe next year?

The first one I'm aiming for is Dragon*Con's Robot Battles in early September.

The custom magnets are on their way from china now, and should be in the US within the week! I'll also be doing a fair deal of physical layout work tonight and tomorrow.

Current iteration of the weapon disk:

The geometry on the very center portion of the disk will make a bit more sense later, but the disk essentially slots directly onto the flux ring/motor can, eliminating the need for heavy screws.

Oh, and current OD [outermost distance the weapon reaches in a single rotation] is 3.5", with a .25" tooth and 3" ring. The whole thing is .125" thick steel.

Current layout progress:

Hardest parts are done, now it's basically adding ridges & pockets in all the right places to have things fit dead-on with minimal assembly & maintenance effort.

reminds me of lucky strike from carrolton

your gonna have to practice driving. its going to tip going forward to reverse

Cody Harris wrote:

your gonna have to practice driving. its going to tip going forward to reverse

That'll depend quite a bit on the final weight distribution (which will be slightly in front of the wheels), and may be averted altogether by a small structural change.

"and may be averted altogether by a small structural change"

Like going back to being a horizontal?

rjw wrote:

"and may be averted altogether by a small structural change"

Like going back to being a horizontal?

No, more like flipping the motor & drive ESC's positions.

EDIT: oh, and the weapon motor's magnets are now on their way! (should be here next week)

Current Progress:

Happening now:
-Adding features to ease wire routing
-Adding final portions of the armor

To do:
-Apply remaining features to constrain components on X, Y, and Z-axis in real life via the support structures and baseplate. Aim for minimal fastener use.
-Apply full weight reduction

EDIT: Magnet update: they should be here Tuesday/Wednesday

Once more, murphy conspires against me and has resulted in another layout shift, this time to a different body plan for the same basic vertical disk. However, since I promised some details on what I'm doing differently (or potentially not so differently for some of you) as far as pocketing goes, here's what that's all about:

Instead of pocketing all the way through, leave an ultra-thin layer of material in the pocket. For those of you who have not taken a deformable bodies course, this makes no sense at all; for those of you who have, you've just realized what this does. The thin layer, while weak and able to be bent very easily on its thin dimension, is still quite thick in its other two dimensions. This means it will very strongly resist forces in those two directions, leaving the entire plate in a more sturdy state than if the pocket had been cut all the way through the material. This principle is the same that is seen in the common I-beam, where a few much thinner and lighter sections of material provide close to the same strength of a giant bar without all that empty space removed.

that how alot of our pocketing is done
depends on where you look though

That's why I pointed out that this was probably not too far off for many teams. This just points out that when choosing to make a structural component a truss (cut all the way through) or just pocketed to a set depth, you get a lot of extra strength out of leaving in even the tiniest sliver of material.

Alright, the new layout (which I believe will indeed be the final layout) is basically a Nightmare-like layout (long, thin body with weapon in front and two motor pods for drive on spindly legs). Also: wow, this layout is light. Amazing what a change in shape will get you - I may be able to cover the entire thing in 1/32" steel!

As an addendum to the pocketing discussion, I realized today failed to get my point across very well: the remaining wall thickness has only a small effect in the greater scheme of things, as long as some material is left. In fact, you could leave a .001" wall and still reap major strength benefits over cutting all the way through the plate. For those of you who don't believe me, try this simple example:

1. Place a sheet of paper flat on a desk, and do not allow it to loose contact with the desk at any point in time.
2. While doing this, attempt to tear the paper by applying tension (or compression) along its width or length. You will find you cannot easily do so without violating #1.

The current chassis, minus fasteners, some supports, a bit of weight loss here and there, and some extras: 0.745 lbs. Biggest hurdle to overcome: how to make the motor pods durable enough to take undercutter/horizontal hits (I'm thinking Al channel).

I liked the 'Lucky Strike" design better--what happened?

rdubard wrote:

I liked the 'Lucky Strike" design better--what happened?

Weight happened - believe it or not, that whole design was significantly heavier than this one (primarily due to the weapon mounting structure/front wedge). This one should still perform quite well, I'll just need to take a few precautions concerning inversion & drive system vulnerability.

Another antweight update:

The drive system leg issue has been solved with the use of 1/2" lexan/polycarbonate stock and extensive pocketing. I'm pretty sure 95% of antweights will have some issues totally destroying the legs in any reasonable period of time, and I'll be able to make plenty of spares (these things are going to get chewed up on a regular basis, so I might as well).

[still unnamed] Antweight, final qualification build #1: (spoilered for many images)

Spoiler:

Spoiler:

Spoiler:

Spoiler:

Spoiler:

At this stage, all I have to do is add fastener holes in the last few areas and a little work on some wire routing design/layout (drive & weapon). Other than that, I'm almost ready to go and buy stock. By my estimates, it currently sits at a comfortable .90-.95 lbs, and there are a few places yet where I could pocket if necessary. But! Before that, what does everyone think? (Questions? Comments? Critiques? Obvious and horrible flaws*?)

*to address the most obvious three, the front standoff (prevent weapon/ground contact during hits) isn't in yet and I've left out a carbon fiber roll bar & wheels [I did verify ground clearance for the blade with a sketch in place of the wheels though].

I'm not a really big fan of large diameter verticals, so my first reaction is ...

baaaaaaaaaaaa waaaaaaaaaaaa yeeeeeeeeeeeee owwwwwwwwwwwwwww

Getting past that, let me ask this....I see the polycarb motor mounts, but is the rest alu?

If so, why not use something tougher around the wheels and maybe take some weight away from the tail section.

Also .9 to .95 of a pound doesn't sound really comfortable weight wise (to me) that's like between 20 and 45 grams ????

I hope you have the receiver, wiring, battery , switch(s), solder, shrink tube and all the little screws and gizmos calculated in there...heck, a piece of 1/4" high desnsity foam can weigh 10 to 20 grams.

are you still planning to clad it with steel armor? or is this it???

I can never seem to even begin to look at getting an ant under 1 pound, not with hardly any metal structure.

Do you have a spreadsheet or list of the components and their weights???

rjw wrote:

I'm not a really big fan of large diameter verticals, so my first reaction is ...

baaaaaaaaaaaa waaaaaaaaaaaa yeeeeeeeeeeeee owwwwwwwwwwwwwww

Getting past that, let me ask this....I see the polycarb motor mounts, but is the rest alu?

If so, why not use something tougher around the wheels and maybe take some weight away from the tail section.

Also .9 to .95 of a pound doesn't sound really comfortable weight wise (to me) that's like between 20 and 45 grams ????

I hope you have the receiver, wiring, battery , switch(s), solder, shrink tube and all the little screws and gizmos calculated in there...heck, a piece of 1/4" high desnsity foam can weigh 10 to 20 grams.

are you still planning to clad it with steel armor? or is this it???

I can never seem to even begin to look at getting an ant under 1 pound, not with hardly any metal structure.

Do you have a spreadsheet or list of the components and their weights???

Yes, the entire chassis other than the motor mounts is aluminum (except the top & rear plates), and the chassis is already mostly pocketed. I could thin out some sections a little more if I had to though, but I'm aiming to avoid that because around the tail section is where the lipo lives . Additional wheel guards basically fall under the "If I have extra weight, that's what I'm adding" category.

I've already got a spreadsheet for the other internals, and some considerable leeway for more pocketing, so I'm fairly confident about weight. Around a third of the weight is internals, but I will have to be cautious about wire length though.

I've abandoned steel armor, as 1/8" Al seems to be ridiculous overkill in most situations for ants (from what I've seen). I do expect it to take a beating, but a 12"x12" sheet will make many chassis. Each plate itself is pocketed leaving a 1/64" wall [yay precision CNC milling] and 1/8" trusses on top, bottom, and crosswise in triangular patterns.