View Full Version : Ramp help
Our robot is having problems getting up the ramp (backwards unable to pull itself up the ramp and forwards tipping over) so if anyone would be able to provide a quick effective solution it would be greatly appreciated or even just brainstorms
<edit> quick responses are appreciated since our last day of comp is tomorrow</edit>
Thank you from me and i am sure the rest of the team
Tomasz Bania
24-03-2006, 21:23
Our robot is having problems getting up the ramp (backwards unable to pull itself up the ramp and forwards tipping over) so if anyone would be able to provide a quick effective solution it would be greatly appreciated or even just brainstorms
Thank you from me and i am sure the rest of the team
If you could, balance the weight more efficiently.
Tomasz Bania
if the problem is traction i would suggest putting on the innovation first tread to gain some extra pull. you could also gear down your wheels by putting on a bigger size of gear on the actual wheels. you would loose a little speed but gain the torque needed. if you have the weight and some wheels, omni-wheels may or may not help. they could pull up the ramp depending on the situation. does that help at all?
thank you very much for your speedy responses but traction is not an issue and as for redistributing weight we don't have much to work with. so any other ideas?
last year i recall 340 actual making a quick battery hoder and riveting it on in a differnt place to shift our weight. it worked great. the moving around of 13 pounds works good. another idea is if you have a compressor, try and find a place to put it were you need the weight. there is 20ish shifted pounds right there. i hope that this helps.
Uberbots
24-03-2006, 21:32
well, you cant do much else but redistribute your weight. Without a low center of gravity, you cannot get up the ramp.
unless, though, you have some weird robot that requires a special routine in order to climb the ramp. in that case i would talk to your programmer to develop that routine.
I wish i could help you more man, but without your robot in my view thats kinda hard to do.
--ss32
(sorry read my next post... i dont think i read your description of the problem clearly enough :o )
last year i recall 340 actual making a quick battery hoder and riveting it on in a differnt place to shift our weight. it worked great. the moving around of 13 pounds works good. another idea is if you have a compressor, try and find a place to put it were you need the weight. there is 20ish shifted pounds right there. i hope that this helps.
hmm... that would be a great idea but i am not sure if our robot design would allow that... but thank you anyway. so anyone have the miracle idea to help us get up the ramp? (our motors should have enough power to push us up)
Liz Smith
24-03-2006, 21:40
Maye just try to get a little momentum by starting further back, if you're not doing that already.
thats alright. im not giving up yet :yikes: . it sounds like you have 4 wheel drive. if this is the case, make it 6 wheel drive. this will enable you rear 2 wheels to act as a wheelie bar. thats all i can think of for now.
Uberbots
24-03-2006, 21:43
Oh wait, it is simply unable to pull itself up the ramp? well ok then.
What you need to do (well what we did anyway) is approach the ramp slowly, but then GUN the motors as soon as youhit the ramp. That way, you shouldnt flip like you would if you rammed the ramp. Im not sure if this method will work for your robot, but its worth a try right?
we tried that it actually led to slight tread damage and our wheels bounced off the ramp so it was unsuccessful but keep feeding me idea I appreciate the responses thank you everyone and keep 'em coming.
how far up the ramp do you make it before you flip? :)
Uberbots
24-03-2006, 21:48
we tried that it actually led to slight tread damage and our wheels bounced off the ramp so it was unsuccessful but keep feeding me idea I appreciate the responses thank you everyone and keep 'em coming.
OH so you have a tread system... thats new.
Well then, what i would sugest is work a strategy out with your alliance. tell them that you need help with the ramp, and if the time doesnt allow then you could help push them up.
without some design modifications, im sorry but you just cant get up that ramp.
Mr. Freeman
24-03-2006, 21:48
1. Move battery to front of bot.
2. Move ?????? to front of bot
3. Post picture of robot to increase helpfulness of responses.
4. Attach bars that slide out so that they hit the ground when you climb up the ramp, like a wheelie bar. Perhaps have some sort of ratchet mechanism so they don't then slide back in when going up the ramp.
im not an engineer or something but in our robot, it was difficult to go up to, but some how during the match we diecided to have our shooter wheel on top speed rotating towards the ramp creating somekind of a momentum towards the actual ramp and the robot acctually climbed up, it will take few tried before u perfect it.
not sure if this (http://robotphotos.org/d/63491-3/IMG_6082.jpg) helps but this is a picture of our robot doing the ramp.
how far up the ramp do you make it before you flip? :)
Well not very far but we never actually measured . (we have 4 rear wheel drive with the cool treads and 2 front "wheelchair" wheels just slightly off the ground so they can roll when we go up the ramp but dont hinder our turning) please keep the helpfull responses coming because even if you dont give me the idea you may inspire me to think of it so please keep 'em coming.
Unfortunately I don't have any pictures to upload.
spinning wheel idea is interesting if it works
Nitroxextreme
24-03-2006, 22:07
This may not work with your robot at all...I really have no idea what the overall design is...
What you have been saying so far is that you have alot of traction in the back and no touching in front.
Again I'm not sure if this would work...but it may be possible to go up the ramp sideways. If you go up the ramp on an angle you wouldn't have to take the complete angle with all of that traction. Center of Gravity would be the only questionable factor here.
Any Pictures could help with troubleshooting...even microsoft paint drawings if pictures are difficult to find.
TubaMorg
24-03-2006, 22:39
Hmmm to summarize the problem: You can't go up the ramp forwards because the robot flips. You can't go up backwards because your wheels slip right? And you have 6 wheels....the rear 4 wheels are drive wheels and the front wheels are slightly off the ground as "idlers".
My suggestion is if possible to get a running start at the ramp, running backwards so that momentum will carry you far enough up so that your drive wheels gain the top. Another method is to allow an alliance partner to boost you up (again going backwards).
Good luck!
Greg Marra
24-03-2006, 22:44
What we did when we couldn't ramp was made the front of our robot like a "sled" so it would slide up easier.
The front (or back) of your robot probably looks like a right angle. Take a saw and cut it so it has a 45 degree angle instead. This way, when you run at the ramp at high speeds, some of your forward momentum is converted into upwards momentum to help you get up the ramp.
hmm...well i managed to scrap up some photos so heres the links:
Side view (http://www.chiefdelphi.com/media/photos/24036?)
Front view (http://www.chiefdelphi.com/media/photos/24037?)
Ask and ye shall receive :)
now I hope I get some brilliant ideas and hope these are good enough.
If you use smaller wheels on the front it should not push your robot back as far and then not flip you, try that its a fairly quick solution, also hack off any of that stuff on the fron at the bottom that isnt needed so that you could lift those front wheels even more
If possible you could have your alliance partners push you up the ramp. We pushed several high profile robots up the ramp at Peachtree.
Just a idea a fast and simple one.
Cactus_Robotics
24-03-2006, 23:10
Do you have bumpers? My team found that w/o bumpers our team would topple over but when we tried it during a actual match w/ bumpers we could get up no prob. the extra weight at the bottom did a lot to help us.
all of those are good idea maybe combining some will get us there but please if anyone can think of anything else please share.
Well I am going to bed and I will check in the morning to see what amazing ideas the night owls come up with.
good night and good luck to everyone.
looking at the side view, i would say move the middle wheel forward to enable more traction towards the front. this would also allow you rear wheels to catch the robot from tipping backwards, like a wheelie bar. this means cutting off that support piece in front of the middle wheel. maybe move that support piece between the two back wheels. so, move the skyway wheels as far forward as possible and move the middle wheel forward according to that. i don't know. that is my best suggestion so far.
You guys all made great suggestions but if anyone else has others please do share them because the more ideas I have to run by the team the better. You can even agree with someone else's idea if you like but I would like more input on this matter before I leave in like an hour and a half. Thank you all very much for your time and support.
Well I am leaving for the competition now so your ideas wont do much good for me but you can give more anyway for others or just to simply share knowledge thank you all very much for all your input you have been helpful.
Daniel_LaFleur
27-03-2006, 07:31
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 :(
s_forbes
27-03-2006, 09:20
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
Tetraman
27-03-2006, 19:09
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.
Tetraman
27-03-2006, 20:22
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
POLISH703
27-03-2006, 20:50
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:
StandingInRain0
28-03-2006, 15:00
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>
Rick TYler
28-03-2006, 15:35
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.
vBulletin® v3.6.4, Copyright ©2000-2017, Jelsoft Enterprises Ltd.