Alright, we’ve heard many folks talk about how generally awesome the Kitbot can be for teams. (I’ve said it quite a few times myself.)
I’d like to know from the teams that rolled their own frame why they chose to do so. Was it weight? Force of habit? The desire to do something different? Something else I’ve missed completely after being spoiled for two seasons by the Kitbot?
(Just as a note: I’m not saying one way or the other is better. I just want to know why the other side does things like they do. It makes life interesting.)
The primary reason is that we can do better than the kit frame (and gearboxes) can provide us. Whether or not that gives us any advantage on the field, I believe it does good things for the skills of the students on our team. We built an incredibly robust and lightweight frame from aluminum box tubing. The way we had our wheels, pillow blocks, and chains setup would not have been possible with the kit frame. We were able to save space and weight by putting a lot of design and fabrication into our own custom frame (and drive system). Also, on a more personal level, I don’t believe that all robots should look the same.
I guess we didn’t because we’ve gotten used to the versatility of T-slot aluminum. We don’t have in house welding capability so building a really good custom frame isn’t possible. We did, however, use the kitbot frame as raw material for brackets and such.
For the past two years my team has used the kitbot frame, simply for the convenience. Next year we are planning to make our own frame (or at least get the kitbot frame welded) because while it is sturdy, it is also VERY heavy. I have heard you can save 10 lbs or so by welding instead of using all those bolts.
We’ve used the kitbot frame the last two years, and I like it. However, I want to make a custom frame out of welded box aluminum next year to save a few pounds, and save space by designing to the size you need, not like the KitBot frame which is designed to be usable in many configurations. (ex. a two inch wide wheel well instead of 3" ish size. (Or is it four?)) Fiberglass make make an appearance too.
We didn’t use because the T-slot aluminum seemed so good. We also saved a bunch of weight. It is hugely flexible (adjustable) for things that you don’t know exactly where they’re going to go.
BUT… our frame was not as impact resistant as with the kitbot we used last year. The T-slot fasteners don’t handle shock that well. 20mm T-slot is not as bend-resistant as it seems.
For next year, we’ll probably use the kitbot for the lower part of the frame, and T-slot for the upper part. Or maybe hand-laid fiberglass-epoxy. Or machine it out of a solid block of titanium…
With our swerve drive this year, a kit frame would have had to gone under heavy modification to fit our needs, and since Baxter provides us with an awesome machine shop (and Dawson, the best welder in the world), we went ahead with our own frame. I personally see nothing wrong with the kit frame, we did use it last year after we modified and welded the heck out of it and it withstood a lot of crushing impacts (most memorably a head on head full speed impact between us and SPAM last year at nationals) with little more than a few small dents. Given the opportunity though, I would almost always choose a custom frame mainly because you know you can engineer it how you want so that it fits your needs with out risking structural integrity.
For any team that wants to save some cash or doesn’t have the capabilities to build their own frame, the kit one is really a good deal (especially when you strengthen it a bit).
our team didn’t use the kitbot this year because we knew like 696 that we could make a better one for ourselves. we used 2x1 aluminum 1/8 thick tubing and welded a frame (like 254, 60 etc) it is much easier to work with but requires the ability to machine. it worked out well for us and is extremely strong. also the most important feature is that when you finish you can powdercoat it and make it look really sharp because it doesnt matter if it runs well it just has to look good right?
-guy
We wanted to challenge ourselves with designing our own chassis
We managed to bend up the kitbot chassis in triple play, so we wanted something a bit more robust. We still managed to bend a few of our framerails. (1/4"x3" 6061 aluminum, with some speed holes)
We used the kitbot all right–for testing. Makes big heavy shooter prototypes much easier to move around. We have pretty much always used our own frame. A good reason not to use kitbot: robot droppings, such as the bolts for the frame.
Good point. Actually, we did too. We used the KOP frame and gearboxes to give the programmers something to work with before we had a real robot. They much enjoyed it.
We have gradually welded more and more of our robot frame over the years, using 6061-T6 aluminum box tubing. It avoids the weight of the attaching hardware and avoids loose nuts and bolts. This has been so successful it appears that we will be upgrading to a higher current welder next year so that we can weld thicker aluminum sections with impunity.
Really??? What problems did you have exactly? We used the Kitbot frame and riveted it together with 1/4" aluminum pop rivets to save weight and get rid of those pesky KitBot frame nuts and bolts that keep falling out. We never had a problem and the frame is as solid and tight today as the day we put it together in January.
Actually, we did use a kitbot frame in competition this year. When our powder-coated robot decided to hang out in SoCal until Thurs night of the Greater Toronto Regional, we obtained a kitbot frame from the TechnoKats to build the “One-day Wonder”. It was very easy to assemble, quite strong, and though not the most mass efficient chassis, it was quite acceptable. The predrilled holes for the axles (with the center wheel axle slightly lower than front and back) and transmissions makes assembling the drive components very straight forward. Next year, we’ll have our “newbies” build a drive base from the KoP frame and transmissions so they can have a driveable 'bot early in the build season.
P.S. Guy says a good looking robot is better than one that is running well just to “jerk my chain”. I guess I’m just not one of those “form-over-function” people.
The kitbot frame could be improved (we collapsed parts of it this year just from our conveyor belt to pick up balls), and is impracitcal for some drive systems. I think building our own chassis would be interesting; however with no machining or even welding capabilities, our team is quite happy to get the kit frame than trying to invent something of our own with nothing but hand tools like we’ve had to do in the past (I think we might have managed to get someone to do a tiny bit of welding for us). The kitbot works very well, and unless you’re a team who knows what they’re doing, I think it’s the best way to go.
Of course I’d just love to do a fiberglass or wood frame and be totally custom, but I’ll stick with what we can do for now.
We used the kit bot last year and it bent and racked.
My self and some of the other mentors knew we could do stronger and lighter with welded box. We took a ~13 lb kitbot and replaced it with a sub 2 lb box frame. We however have access to welders who weld thin wall tubing all day long.
