pic: 6WD Design Iteration

[lukevanoort]

Originally Posted by wilsonmw04

Being from a team that does not have an in-house machine shop, this design is very interesting. What are the outside rails made of? Is there some sort of track that the wheels are sliding on to provide tension?

The outer rails are made out of T-slot aluminum extrusion, probably made by either 80/20, Bosch Rexroth, or Item (In this case, I think it is 80/20). Specifically, it looks like either 1.5" (40mm if metric) or 1" (25mm if metric). The pillow blocks are probably held in by t-nuts and you'd just loosen the t-nut and slide the wheels to tension. One of the wheel pairs (looks like the front ones) is usually powered directly off the output of a transmission (like an AndyMark SuperShifter). This one could also power the rear wheels by chain and transmit power from the rear wheels to the front.

Although this is much simpler than the West Coast drives that you see made by teams like 254, 4, 968, 60, etc., it probably would be a challenge to make without a machine shop (due to the custom machined pillow blocks). You could probably make it without a machine shop if the outer wheels were running on dead axles (eliminating the need for accurate pillow blocks) and if the center one was directly mounted onto the output shaft an AndyMark SuperShifter (probably using the extra-long output shaft upgrade). You could then use bumpers to protect the chain runs from the center-front and center-rear wheels from being damaged by other robots.

BTW, this design is great! It is definitely going into the collection of possible drive designs for next year. If we are collecting balls again (or something else that requires a ton of vacant space in the center of the robot) I'm definitely going to propose this. Great work, Madison!

EDIT: Okay, now I'm almost 100% certain that it is 80/20 extrusion, because I see some 80/20 Quick Frame in the middle holding in the battery. Between the the smallish extrusion on the sides, C-channel front and rear, and the 1/16" wall tube in the middle, this thing must be pretty dang light.