Re: Sheet Metal vs KitBot
 

Did you use independently steerable swerve modules for the Ackermann and compute the inside/outside Ackermann steering angles in software, or did you design a mechanical linkage capable of doing that?

Re: Sheet Metal vs KitBot
 

We used a mechanical linkage to do it. It was actually 4 wheel Ackerman (don't know if this setup has a different name). The front wheels would turn one way and the back wheels would turn the opposite way, while the inside and outside wheels also compensated for the variable radii of the turn.

We did this for Lunacy and it was really cool when it was working however we had some massive issues with some couplings we were using (the tolerance needed to be tighter than we thought) which prevented us from ever getting to really show it off in competition.

~DK

Re: Sheet Metal vs KitBot
 

Did your team ever post a paper or a presentation with some details?

Re: Sheet Metal vs KitBot
 

Here is a picture of it partially built. We didn't ever put together a presentation or anything like that. The helical couplings were what really made it happen for us.

~DK

Re: Sheet Metal vs KitBot
 

The drivetrain is an iteration of what weve run for a few years now. We collaborated with 1323, so they inherited our design.

You are correct that it is not welded. This made it faster and easier four us to build as welding has always been a bottleneck for us.

Re: Sheet Metal vs KitBot
 

Were there any major downsides to not welding it?

Re: Sheet Metal vs KitBot
 

It did make it a big uglier, as we put bolted some "endplugs" inside the frame rails, and then the crossmembers bolted to them. So we had some bolts and holes where we usually have nice clean frame.

Other than that, no. It worked out great. It was identical to this frame here, minus the intake and crossmember.

Re: Sheet Metal vs KitBot
 

Whoa. Those couplings are not meant to flex that far.

Re: Sheet Metal vs KitBot
 

Which is probably what led to this:

OTOH, FRC robots have such short lifespans it is kind of neat to see things used outside of their original purposes. (Obviously though, you've got to do some testing to demonstrate that it will actually perform)

"I don't care about what it was DESIGNED to do... I care what it CAN do." -Gene Kranz during Apollo 13

Re: Sheet Metal vs KitBot
 

We got them from Helical Products Company and this was one of the main things we discussed with them. The couplings we had were operating within their spec. we worked a lot with that company that year and I can assure you that it was not their fault. The shafts that we had put into the wheel side of the coupling were a few thousandths undersized, not enough for us to worry too much we figured we would have enough adjust-ability by tightening the end of the coupler. We were wrong. What ended up happening was the coupling would spin but the shaft was not held tight enough so the wheel shaft didn't spin along with it. It was in no way an issue of over angling the coupler or an issue with the quality of the coupler. Helical Products Company was a great recourse for us and in the end we made a fatal error.

~DK