Community/Open Source Chassis Project

Originally Posted by sanddrag

Back when I started in 2002, we didn't get any of this handed to us. We had to figure it out ourselves. It was hard, and we learned a lot. What good is this program if robots are just entirely put together from a kit and instructions? We're losing the design and analysis aspect of the competition here.

Agreed. The goal of only releasing the CAD, and requiring any teams that actually build it or modify it to also share the CAD is to promote advancement and collaboration of a design. We're not giving them a box of parts; we're giving them a vague design (that probably has errors somewhere, I haven't spent much time on this design...), and letting them decide on the implementation.

[Billfred]

Originally Posted by sanddrag

Back when I started in 2002, we didn't get any of this handed to us. We had to figure it out ourselves. It was hard, and we learned a lot. What good is this program if robots are just entirely put together from a kit and instructions? We're losing the design and analysis aspect of the competition here.

Counterargument: How inspiring is this program if a big chunk of your regional is spent stuck in your starting square, or sending out a human player while the robot remains stuck in the pits? Give teams a solid baseline, then let them optimize as their resources (time, money, manpower, machining abilities) allow.

To that end, I might suggest getting in touch with the entities behind the 2009 kitbot. If you can come up with methods of improving future versions, either in durability, versatility, cost, or ease of use, your work may get more use by teams than a separate design posted to CD. The kitbot might go against some of the design sensibilities you or your team relies upon, but what better way to help teams than to help improve the aforementioned baseline?

[s_forbes]

Originally Posted by ,4lex S.

A Gallery of past successful designs in great detail (CAD files, images, calculations, written explanations...) would probably become one of the most useful tools for FRC design out there. I know how helpful the FIRST Canada galleries (http://www.firstroboticscanada.org/site/node/96) can be when looking for ideas, and this sounds like an expansion on that idea, so I say go for it.

Otherwise, it might be helpful to incorporate Kit frame based designs onto this page as well. It is a great oppourtunity to play with 6WD and Mecanum designs without going into heavy manufacturing. Giving rookie teams access to things like incorporated supershifter designs, or chain tensioning systems could enhance their on field performance without too much work for them.

Well put, this is what I had in mind as well. A large collection of "what works" would benefit inexperienced teams immensely.

Originally Posted by sanddrag

Back when I started in 2002, we didn't get any of this handed to us. We had to figure it out ourselves. It was hard, and we learned a lot. What good is this program if robots are just entirely put together from a kit and instructions? We're losing the design and analysis aspect of the competition here.

This is one of those things that can be ferociously argued either way (similar to the mentor debate). My opinion is that time is better spent focusing on the strategy of the robot or some complex manipulator rather than trying to figure out small annoyances in the drivetrain.

Originally Posted by Billfred

To that end, I might suggest getting in touch with the entities behind the 2009 kitbot. If you can come up with methods of improving future versions, either in durability, versatility, cost, or ease of use, your work may get more use by teams than a separate design posted to CD. The kitbot might go against some of the design sensibilities you or your team relies upon, but what better way to help teams than to help improve the aforementioned baseline?

This is also a good idea, since the kit chassis works so well for so many teams. As ,4lex S. mentioned, putting up different configurations for the kit frame would be helpful. I think it would also be good to provide ideas for teams that want to go past the kit frame too, for the small number of teams who prefer a design that won't work well with what's provided in the kit.

[AdamHeard]

I believe the open source chassis would be much more effective if it utilized the kit frame.

The kit frame doesn't out of the box offer a decent 6 wheel, if you guys just make the simplest method of making a 6wd with the KOP frame, people will probably actually use it. Pretty much, use all COTS parts, make some assembly and exploded drawings with complete BOMs, and release that. Dawgma did that a few years back for a non-KOP base (I believe it was the "sub $1k drivetrain").

Sorry to rain on the parade, but a team capable of making the kinds of bases you describe probably don't need or don't want to download a design. Now, the team that meets in a physics room and has no engineering mentors would probably actually use (and be able to use) a 6wd with the KOP frame.

Pretty much, if they have the capability, they won't want the design, and if they want the design, they probably don't have the capability.

[GUI]

I disagree. I am talking about a design that would require very few tools (i.e. a saw and a drill), yet would be simple and competitive. The kitbot is nice, but rather than trying to make it work better for a maneuverable, dependable chassis, it makes much more sense to start with a clean slate. It is surprisingly easy and inexpensive to build a frame that is much more suited to your needs than the kitbot, and I think that doing so will make many teams' lives easier.

[AdamHeard]

Originally Posted by GUI

I disagree. I am talking about a design that would require very few tools (i.e. a saw and a drill), yet would be simple and competitive. The kitbot is nice, but rather than trying to make it work better for a maneuverable, dependable chassis, it makes much more sense to start with a clean slate. It is surprisingly easy and inexpensive to build a frame that is much more suited to your needs than the kitbot, and I think that doing so will make many teams' lives easier.

I will be extremely surprised if someone can design a frame entirely constructed from hand tools that will be better than a KOP frame designed into a really simple 6 wheel. I bet it could be even be done without using any hand tools if designed well enough.

Originally Posted by AdamHeard

I will be extremely surprised if someone can design a frame entirely constructed from hand tools that will be better than a KOP frame designed into a really simple 6 wheel.

I know this is a cocky statement, but you're on.

[AdamHeard]

Originally Posted by CraigHickman

I know this is a cocky statement, but you're on.

Let me define "better".

The people this frame should target is the team building in a classroom with no real tools available to them, an adviser that disallows tool use, or a school that disallows tool use. So, it should be a competitive 6 wheel drive that uses no machined parts, and hand tool operations should be minimal.

I really don't see how something else could beat the KOP in this aspect.

Originally Posted by AdamHeard

Let me define "better".

The people this frame should target is the team building in a classroom with no real tools available to them, an adviser that disallows tool use, or a school that disallows tool use. So, it should be a competitive 6 wheel drive that uses no machined parts, and hand tool operations should be minimal.

I really don't see how something else could beat the KOP in this aspect.

So far I've got a basic chassis. I'm designing around only two tools: Power drill and a hacksaw. I MIGHT add pop rivets, but only because those are available from McMaster for pretty cheap.

[GUI]

I think you underestimate how simple it can be to build a custom, effective chassis. I have several ideas that would require cutting a few boards of wood, drilling some holes, cutting sheet metal, and screwing/bolting.

That being said, the situation you describe is very specific. I doubt there are many teams that cannot get access to basic equipment (or someone who is willing to do a minimal amount of basic work) for a few simple parts.

[s_forbes]

Originally Posted by CraigHickman

So far I've got a basic chassis. I'm designing around only two tools: Power drill and a hacksaw. I MIGHT add pop rivets, but only because those are available from McMaster for pretty cheap.

Originally Posted by GUI

I think you underestimate how simple it can be to build a custom, effective chassis. I have several ideas that would require cutting a few boards of wood, drilling some holes, cutting sheet metal, and screwing/bolting.

Both good, but Adam is talking about how the kit chassis only needs wrenches to assemble.

EDIT: how many teams actually fall into this catagory of only being allowed to use wrenches/screwdrivers/etc.? I also have a design that I'm almost done with one that requires only a saw and a drill to assemble (and is cheap! )

[sanddrag]

Originally Posted by AdamHeard

I bet it could be even be done without using any hand tools if designed well enough.

I bet one could build a pretty darn nice robot with nothing more than an internet-connected computer, a telephone, and a credit card.

Of course that isn't the point here, so, carry on...

But yes, teams with no real tools or workspaces do exist, and I suppose readily available simple solutions do help them get off on the right start and stick around in the program.

[Cory]

The assumption that the kitbot will remain the same is probably not a good one.

Who knows what we may get. Think back to 2004 and prior-when the kit bot was really pretty useless. It might be a regression from what IFI has been offering us, if it's different. It might be better. Who knows.

Hopefully if the kitbot is not the same IFI will continue to sell it anyways (assuming it makes sense financially for them).

[Billfred]

I was already beat to the punch on tool use; yes, there are schools that have limits, either procedural or simply for lack of them. So I'll add in another constraint to consider: purchasing.

Not all schools or institutions have FRC-friendly procurement rules; some refuse to let someone go out-of-pocket and get reimbursed, others can only write purchase orders that not all merchants accept, and still others will be glad to cut you a check--Monday mornings between 9:15 and 9:45 AM, for an exact documented amount, if the hand of the bookkeeper that signs such checks hasn't cramped up. (Trust me, I have some interesting state purchasing tales.)

If you can cut the number of suppliers down to one or two, the odds of that bookkeeper's hand cramping up is lessened.

For 2008, a team with a firm grasp of physics could build an effective (wide-track, for the sake of argument) 2WD robot with one hacksaw, one drill and bit (to enlarge the axle hole to 1/2"), one allen key, one wrench, and four 1/2" nuts and bolts. Even if nobody on the team had them to loan, you could pass the hat around and buy all of that for $100 at any hardware store in the country. (International teams might have more trouble; someone from abroad want to comment on how the IFI frame went together for your team?)

Also worth considering, for the folks talking about hacksaw-and-drill approaches, is the risk of That Freshman. (Not all freshmen, mind you, just That Freshman. You know the one.) If your material of choice is available cheaply in big huge sheets, you're probably fine. If That Freshman's mis-angled drilling is going to run a team $20 each time, it's a factor. (And, of course, remember that the kit frame's materials are there for free, whether used for their original purpose or some other; teams may also be able to wheel and deal for more of it from other teams.)

If you still think you can beat the kit frame of past or near-future for the above (and let's not forget enough durability to last the season), I'm much interested in seeing.

[GUI]

My intent with this was not to make a frame that can replace the kitbot as being easy to assemble with so few resources, but to create more of a library of designs for teams with limited machining and mentor resources. S_forbes posted a design that is very similar to one I was working on here. The materials are readily available, it requires very little machining (biggest task is drilling the bearing holes, which can be doen with a forsner bit on a drill press), and is inexpensive.