Right time for another write up, this build log will revolve around my newest robot [BIG SHOT], my first dip into the bigwheel archetype of robots and my fleeting attempt to rid the class of its cancerous obsession with forks.
The bigwheel archetype has always been rather appealing to me with a few major advantages and setbacks. First and foremost the biggest advantage to having the high ground is the (near) immunity to forks, not playing the ground game yourself and ideally being unaffected by it sounds like a dream come true for me and I imagine most builders.
The general layout of a vertical spinner bigwheel also allows me to comfortably fit a large weapon on it to keep up theme with my other builds, this case being a 28g 98mm symmetrical blade, outsizing Vanquish by over 10mm.
Disadvantages however are pretty major unfortunately, which has put me off of it for almost a year now. The ever looming and mood ruining 150mm square rule, and my design incompetency with tethering the 2 sides together. First off while I could technically start on my side to avoid the size limit, its a big invitation for a box rush, and I dont like the sound of that with the prevalence of pits.
For connecting the 2 sides together, after eons spent in deep thought and millennia in CAD I decided to be a lazy basdard and rope the 2 sides together with a bridge. It was late and there were to many beers involved for a CAD night, but the genius (or alcohol) set in and I slaved away for hours making quite possibly the worst looking robot to ever grace the forum.
After waking up in the afternoon to this on my screen I decided to run with the bridge idea just to see how far it could get me before I inevitably print it off and snap it like a twig. After a couple days we finally got the first true versions of [BIG SHOT], it would be a 148mm wide, 100mm tall bigwheel with a large, heavy weapon and a similarly large weapon motor, that being a t-motor 2203.5 with a bridge to connect the electronics. Fast forward abit as I dont take pictures and we have the very first version assembled.
It was a beautiful, green, health and safety hazard. But it did drive, and it was underweight. Best of all the bridge was shockingly strong, taking far more effort than I would have thought to break due to the heavy print settings. After a little more testing and some cleaning up we have the finished bot that attended GROCS July a couple weeks back. Important to note this bot was designed and built in an incredibly short time span, only a couple days if memory serves me right, so there was not much hope for him.
This isnt an event coverage thank god, so we will just say [BIG SHOT] did extremely well in its debut, getting 4th place in possibly the most stacked UK ant competition I’ve seen. Still upgrades were needed, mostly focused around the drive, in basic terms it needs more grip to pick its arse off the floor easier, as it would need to make grip on the slick bare TPU wheels to do so, and that’s hard on a steel sheet.
The solution was o-rings, all the way around the wheel. Not because its weight efficient, or because its necessary, or because its grippier than other better materials. But because it’s easy, and it takes 3 minutes of CAD, and only a few test prints to get the thing underweight while keeping the form factor. Right?
Short answer is it took more than I thought and i would rather put exactly 4 fire ants under each of my fingernails than ever go through this process again. There is a few here that may not be from testing but I dont think I care, the mental wound is still fresh and I would like to move on.
The final stretch to where it is as of now, it is currently at weight with even bigger wheels, now sitting 125mm tall with o-rings giving it immense grip and control. Look forward to trying it at ORCS next to Vanquish, but as of right now this is the end. Hope you enjoyed.
