pic: Cheap 6WD

[s_forbes]

Originally Posted by Andrew Schreiber

Looks easy to make, the only concern I would have is can it take a hit? Aside from that, what is the weight and where do I mount bumpers? (assuming they are legal) And how do you tension the chain?

Just a thought but could you save weight by using thin sheet metal as your belly pan?

I'm not sure how well it would survive compared to other frames, but with bumpers I don't think it would have any problems. As squirrel pointed out, bumper mounts on the corners are easy to make and work well. For chain tensioning, I like the nylon-circle-with-offset-hole-approach. It has worked well for us in the past and is easy to do.

A sheet metal belly pan would probably save a bit of weight and could be stiffer, but I laid out this frame trying to minimize the number of parts that need to be bought online. All of the wood parts can be easily found at a home improvements store. (although if we built a chassis like this, it would probably have an aluminum base plate. )

Originally Posted by goffchris

It is not completely clear from the CAD, but remember that:

1) The middle wheels need to be offset lower, or the robot won't be able to turn easily. We are using a .5 cm offset this year, but I have read about teams using 1/8 inch.

2) Many teams use omni wheels on one or both ends (not the middle) to aid in turning. The omnis compromise pushing power a bit, but make turning much easier.

It's hard to see in the rendering, but the center wheels (5" banebots wheels) are lowered 1/8".

Originally Posted by GUI

Looks good, but I think it would be preferable to mount the transmissions in the center, so you can use corner plates like on the front on all three corners.

Actually, having the transmissions in the back has some neat advantages. Since the center wheel is dropped, the rear wheels don't carry as much load. This is probably a lot nicer on the transmissions since the wheel is is about 1.5" from the transmission bearing. Also, with the chain routed this way (one on the inside, one on the outside) the wheels can sit in closer to the frame.