pic: 1817 Teaser #2



Our Wheels + Tread

A look at our wheels with tread and decals which match Texas Tech’s colors, red and black. We covered the screws that hold the tread on with rubber tool handle coating. These will be our middle two wheels. We are thinking of covering the outer 4 with another flat rubber tread. The other option is to cover all 6 with roughtop. Does anyone have any comments on using roughtop all 6 wheels. The wheels are 6" diameter and 1’ wide. We would drop the center two 1/8". Would we have problems turning or going up the ramp?

We make it up the ramp with no problems using IFI’s 6"x1.5" traction wheels with roughtop in a 6x6 configuration lengthwise on the kitbot chassis. Your wheels and configuration sounds similar, so I expect you’ll do fine. Depends, of course, on what the rest of your robot’s ground clearance and centre of gravity are… our CoG is going to rise as we add the turret this week, then drop when we add the bumpers next week.

As for turning we found some “bouncyness” on carpet, but that disappeared as we added weight. It turns quite nicely, certainly better than the 4x4 arrangements we have used in the past.

Cool wheels… isn’t CNC a wonderful thing?

Jason

1/8 inch should be fine for turning (that’s what we’ve got). in terms of going up the ramp, a lot depends on your clearance and CoG. If the wheels are evenly spaced, and you’ve got more than 2" of clearance you should be OK. We’ve gone for 2.75" to be safe

Our clearance geometry on our 6 wheel chassis is fine. One of our engineers/college kids figured that out in inventor. My question is about traction up the diamond plate and the carpet. We are using the SBR version of Roughtop from McMaster and the two questions we have are: Will this tread provide enough grip on the diamond plate ramp to get a 130lb robot up a 30 degree incline. Does this tread provide too much traction on the carpet that the robot’s wheels will jump when turning.

In my years with the Robonauts we didn’t use a 6 wheel base or this type of traction tread. My initial assumption is that the by lowering the center wheels 1/8" that will help with the turning and since the wheels are 1" wide they shouldn’t skip. I also think that the rubber grip that the SBR Roughtop gives should provide enough traction to climb the ramp. It is not as grippy as natural rubber, but with 130 lbs of weight on them we should have not much trouble climbing, esp with the help of 6 wheels.

nice, but the only thing you need is spinners on those wheels