pic: Ramp Video

That specific robot design was ruled illegal by the GDC in the Q&A weeks before the competition.

The Q&A is the only way to figure out answers to designs like this.

You also have to watch out for your max height.

Don’t make the robot 5 feet above the frame, make it 5 feet above the wheel at the lowest point.

How they would test this in the box… I don’t know.

But still, ask the Q&A if you guys go with it. Awesome drive.

<r07>The BUMPERS must be located entirely within the BUMPER ZONE when the ROBOT is standing normally on a flat floor,

The measurement is taken when the robot is on flat floor. We meet all requirements that we have found in the rules. The bumpers are between 10 an 16 inches above the floor when on flat ground.

If I was an inspector, I would measure your robots bumpers with all wheels in contact with the floor . Then I would ask you to full articulate the wheels and then measure the bumpers. If at both configurations the bumpers where with in the bumper zone then I would be satisfied. If not then I would turn this down. I am not an inspector nor am I a member of the GDC. You better Q & A this soon before you go farther. From the picture your bumper height appears to be variable and not fixed or static.

Sure looks like bumper height would remain fixed while on the flat floor as the regs require.

Everyones bumpers will be out of the bumper zone when going over a bump, so if this thing is legal on the floor it seems fine to me.

If the robot is flat on the floor and the middle wheel is articulated up, are the bumpers still in the bumper zone? This really needs a Q&A. Also with the bumpers up high this year, robot frames will be subjected to allot more stress than in past years with the low riders. Make sure those supports are robust.

If the robot is on the flat floor why would the wheels be articulated up? The articulation is not powered. the wheels follow the floor all the time.

The center Omni’s are ALWAYS touching the ground, they never leave the floor. They aren’t powered by anything other than the friction on the carpet when the Mec wheels are moving. The bumpers are in a permanet position. If you use the bump to manuvere around the field then no matter what your bumpers are going to change height. Meaning when you are going up your back bumper will be closer to the ground then if you were on level ground and just the opposite when going down the other side. The bumpers are solid and in the correct height while on LEVEL ground!

We have read the rules many many times and the question has been given to Q & A. We have asked many many teams in our area about it and if this is doable. Most agree with us that it is perfectly fine while others weren’t sure. We are 99.9% sure that we are correct and would be shocked to see anything differently.

Q & A gave us the green light, Yahooo!!!

Yep Joe, Update #3 today also green-lighted it. I really look forward to seeing this design in action! Be sure to post some videos of it during competition.

Thanks so much for the feedback. Our team has decided against having an articulating 6-wheel approach due to the complexity and the limitations of our team but I must say I’m still curious. How does your ball-differential work? From what I understand of ball differentials, there is one drive gear and 2 driven axles. So I assume your center omni wheels are on the driven axles. But you have 2 driving chains coming from the omni wheels and only one drive gear. Do you have a special type of ball differential? Can you explain a bit more?

Thanks again! Good luck with your design. Congrats on getting the green light in Q&A!!

The Mechanum wheels are driven, the chains drive sprokets on the ball differential, between the sprockets are steel balls that are inside a round flange with holes for the balls. The flange is attached to the drive shaft with the omni wheels. Pictures are on our wesite http://www.team1322.org/ideas.htm

Is that the 45degree angle of the ramp? it looked to shalow, and you should build a real bump if possible because it is much harder to test with out the real thing if you know what i mean.

That picture is from one year ago. You can view a video http://www.youtube.com/watch?v=jQMcw4QNCLI

The video ramp is a 45 degree ramp but we had to cut the corners for the low ground clearence of the 6 inch wheels. We will be using 8 inch

Correct me if I’m wrong, but wouldn’t the sections connecting the omnis to the mountings have to get longer/shorter as it tilted? Adding height to the slope gives a longer line.
Unless the mountings can tilt in and out?

The rear virtical strut will pivot at the frame.

It provides a smoother ride than having one single omni at each point. A number of teams have tried single; I believe most of them switched to double at some point.