Chief Delphi - Ramp help

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Looking at the design, your CG is too high and too far back to do much about.

I would suggest creating a wheelie bar. Hang 2 PVC tubes from the back-top of the robot (full height of the robot) so that the will swing out with gravity when the robot tips. Connect them together with a 3rd piece of PVC for structure (box frame). Put rubber boots on the ends of the 1st 2 pieces of PVC so that it does not slide on the diamond plate). use string of some sort to prevent the wheelie bar from going too far.

It wont look pretty, but it should be effective. And sorry I am late in posting, I wasnt on all weekend :(

Pushing from alliance parners works wonders. In one of our matches, the tread fell off of both of our ifi wheels, leaving only metal. Because these were our only drive wheels, we had about 0 traction to work with. Suprisingly enough our alliance partners were able to push us up just fine. It's too late now, but be sure to get someone with a lot of traction on your alliance!

Definitely try using a wheelie bar, just a simple spring loaded device you could even trigger via a servo at the start of the match to support the robot in the rear of hte machine, it appears from the picture to have most of the weight in the rear. Since your front wheels aren't powered, or so i take it they aren't going to counter or help ont he ramp at all.
What's probably happening is like when a motorcycle spins out, it 'pops' up the front end of the bike and in the case of the robot makes it extremely unstable. Best solution is to figure out the CG of the machine and then figure the length of the wheelie bar needed in the back to counterbalance it(and then add a few inches because there's always something thats forgotten).
If you have more time, and a little weight, try moving the wheels positioned in the front up a bit, or making the front wheels wider(say 2"), put some tread on them and smaller so the robot 'leans' forward a little to try and counterbalance whats happening. As for the rear wheel, move it up a couple of inches or figure a way to shift the CG overall closer to the front of the machine instead of the back, but again all depends on fix it time, and the weight u have to play with. Hope this helps

Have 272 push you up. That worked for us!

Or have another team do it, it probly would work just as good.

The bravest and scariest thing I ever saw at a regional this year was the driver who came at the ramp at about 6 to 8 feet per second (flying) straight on, no angle and didn't start breaking until the bot was about half way up. The bot didn't have time to lean back and the carpet side wheels just lifted up and the bot slapped the back wall and came to a stop. It looked like someone had reached down and just lifted the bot straight up and set it back down. It was either a panic move or had been well practiced. Don't know but it was a blast to watch after my heart started again.

703 flys when it hits that ramp. I've seen it happen. It's great when 703's mascot is a Pheonix. So the Pheonix flies

Quote:

Originally Posted by Tetraman

703 flys when it hits that ramp. I've seen it happen. It's great when 703's mascot is a Pheonix. So the Pheonix flies

At buckeye, we got on the ramp to fast in auton mode, and when we hit the wall, the controllers on the other side of alliance wall fell off. :ahh:

Wildstang has a pnuematic pump that pushes out their back bumper which in turn helps push them up the ramp. If you could do something like that, you would be in could shape. Also, don't rush up the ramp cuz you'll hit the wall and go backwards. And don't go up too slow cuz you won't make it all the way.

well we never made it up but the idea I had was for a wheelie bar that dropped down and locked in place and then perhaps by use of pneumatics or maybe a small motor, to have a bar extend out to give a boost up the ramp.

<edit> note we never implemented this idea due to lack of time we tried quicker fixes that failed.</edit>

Not to sound snotty or superior or anything (we aren't -- superior that is), but climbing the ramp was no big deal if you designed for it from the beginning. We thought we would never get picked for a finals alliance without ramp climbing so we made it a priority. Our robot found it easy, and we only used off-the-shelf $18 Skyway wheels with the KOP transmission. Is the problem that some teams didn't make ramp climbing a design priority and they didn't realize how important it was until they attended their first regional? I can see how ramp climbing would be hard if you didn't plan for it.