View Full Version : How good are your tires??
My team and I have been working around the clock to build one of the best drive trains we can. luckly we have finished this new base with some new radical wheels. With these new tires we were able to push one of my mentors around on a steel legged chair on a title floor. We found it very easy to move him around even though our robot only weighted 55 pounds. What do you guys think? Is being able to pull dead weight 4 times your own weight pritty good.
n[ate]vw
21-01-2003, 23:53
Is being able to pull dead weight 4 times your own weight pritty good.
Not necessarily. Our robot last year had beastly rubber wheels that allowed it to drag a large weight around. The wheels actually gave us too much friction and we had trouble with the motors drawing too much current. You need to find the right balance between good traction and allowing the wheels to slip a little to be kind to your motors.
jonathan lall
21-01-2003, 23:55
Well, that all depends on a number of factors. How well can you steer? How good is your lateral traction? How are you on carpet? I'd be interested to know what you've put together.
Sachiel7
22-01-2003, 00:10
RAPTAR has selected some nice tires this year...
They are designed for skid steer (our DT) and pivot well, and maintain good friction for the ramp mesh.
Wayne Doenges
22-01-2003, 09:10
I concur with n[ate]vw about traction.
Last year we had awesome traction. We used conveyor belt material on 6" wide, 3" diameter cylinders. Our 35 pound base could pull me (205 lb) across the carpet with me laying on my side on the carpet. One problem though, it wouldn't turn worth a ..... well you know.
So you have to play a balancing game between traction and control.
Good luck this year.
Wayne Doenges
DaBruteForceGuy
22-01-2003, 11:40
If you think about it, it is quite easy to slide a "mentor" around on a tile (probably lenoleum) floor. We forgo the chair part, and can push pretty much anything around, including mentors, on our slick waxed surface.
Try it on carpet, then you will get a good idea of how much power the drivetrain really has.
Its not always a trade off for Maneuverability or traction. Often teams solve this with plastic front wheels that will slide sideways. This works but the plastic wheels don't give the best traction. Im not even sure if the plastic wheel idea would hold up to the steel mesh this year. My teams base has extrem maneuverability and probly one of the highest coefficients of friction from the wheels that I have ever seen in my 4 years of robotics. This is all done on the basic 4 wheel drive princiable. Im not telling how we accomplished this but I will give a hint, im sure some of you will figure it out, 'battle bots do this a lot with there drive train'.
Robots and brakeable objects don't mix, Oh and don't let the little 9th graders that don't know what there doing put a medal ruler in your chain and sprocket setup. ARGGGGG what I have to put up with
probably lenoleum floor...
Yes it is,
Lets just say, the floor is old and needs a good wax job.
Steel on lenoleum reminds me of glass on glass, both smooth but bind very well.
galewind
22-01-2003, 13:16
We're toying with the possibility of using modified tires that are from a handtruck that will have a significant footprint for better traction (tubeless). We're intending on keeping the wheels fairly shielded. Is having an air-filled tire bad news? Does anyone else use non-solid tires?
It's understood that we'll want to keep a few extra on-hand, but i'm not sure exactly how many of these we should expect to go through. I know those tires are designed to take on a significant amount of weight, which shouldn't be a problem with 4.
All ideas appreciated.
DaBruteForceGuy
22-01-2003, 14:36
Originally posted by galewind
We're toying with the possibility of using modified tires that are from a handtruck that will have a significant footprint for better traction (tubeless). We're intending on keeping the wheels fairly shielded. Is having an air-filled tire bad news? Does anyone else use non-solid tires?
It's understood that we'll want to keep a few extra on-hand, but i'm not sure exactly how many of these we should expect to go through. I know those tires are designed to take on a significant amount of weight, which shouldn't be a problem with 4.
All ideas appreciated.
Yea, pneumatic tires are a great concept, but they are a lil much (if u know what i am getting at). If u look at the reason they were invented, they are made to absorb irregular sufaces on the riding suface. We really don't deal with complications liek that on the rock hard, flat carpet surface. We have all concidered them in the past, but it just turns out to be overkill, the foam insides or softer rubber should be sufficient for the rap curbs and such when it comes to impact and shock absorbtion.
Originally posted by DaBruteForceGuy
Yea, pneumatic tires are a great concept, but they are a lil much (if u know what i am getting at). If u look at the reason they were invented, they are made to absorb irregular sufaces on the riding suface. We really don't deal with complications liek that on the rock hard, flat carpet surface. We have all concidered them in the past, but it just turns out to be overkill, the foam insides or softer rubber should be sufficient for the rap curbs and such when it comes to impact and shock absorbtion.
Pneumatic tires will potentially have a huge advantage on the mesh...anything that can conform to the surface in any manner will
Pneumatic tires are great. we used them last year, and one set lasted through three competitions just fine...ours were very vulnerable, and we never has any issues with stabbing/popping.
P.S. I'd say that wire mesh is an irregular surface:D
Cory
DaBruteForceGuy
22-01-2003, 15:52
Originally posted by Cory
P.S. I'd say that wire mesh is an irregular surface:D
Cory
:ahh: DOPE!!*stabbs self with pencil*-- your right....
I forgot about that..... But i guess that just because we havn't given the ramp much thought....:rolleyes:
Last year, in low speed, our robot could pull it's weight(130) with a goal (120 i think) with a 160lb engineer laying flat on the carpet floor holding the goal(talk about traction). And the thing is, we weren't even among the strongest robot at nationals.
So, don't expect to be the strongest anywhere you go.
team222badbrad
22-01-2003, 16:23
BAH traction is not a problem...
Mike Norton
22-01-2003, 20:46
Last year, in low speed, our robot could pull it's weight(130) with a goal (120 i think) with a 160lb engineer laying flat on the carpet floor holding the goal(talk about traction). And the thing is, we weren't even among the strongest robot at nationals.
Some teams out here have been working on traction for a long time. If you think you have a strong robot just look at the teams that put everything into their traction and motor train.
We were good in strong last year but was as strong as are track could hold. The Breco flex tracks do rip apart under high loads.
I think the best way of getting the most traction is by a track system. but it will take years of proving different design to come up with one that works.
Traction is good but a good driver will always win over a good robot.
HolyMasamune
22-01-2003, 20:52
Originally posted by Mike Norton
Some teams out here have been working on traction for a long time. If you think you have a strong robot just look at the teams that put everything into their traction and motor train.
We were good in strong last year but was as strong as are track could hold. The Breco flex tracks do rip apart under high loads.
I think the best way of getting the most traction is by a track system. but it will take years of proving different design to come up with one that works.
Traction is good but a good driver will always win over a good robot.
I agree that a good driver always helps more than good traction/good robot. Since this year's competition will probably require more manuverability, the driver will be even more important.
Herrmmm.... well.. there is no arguing that the Tread system is the BEST traction out there, the question is just getting the dern' thing working!
our team, after some post-season development, worked it out. The key is to put a bogie-whell in... allowing the 'bot to spin on two small areas while turning, increasing speed about tenfold, and keeping traction still as high as it needs to be.
You need to experiment with which angle is best for your 'bot... but 6 degrees seems to work pretty well..
Our modified bot went:
9 mph, turned on a dime, and exerted approximately 100,000 N at max torque.
Greg Perkins
22-01-2003, 23:01
our drive system is a hybrid of wheeled and walker...hehehe
Bad
esellers
23-01-2003, 15:02
Originally posted by com
My team and I have been working around the clock to build one of the best drive trains we can. luckly we have finished this new base with some new radical wheels. With these new tires we were able to push one of my mentors around on a steel legged chair on a title floor. We found it very easy to move him around even though our robot only weighted 55 pounds. What do you guys think? Is being able to pull dead weight 4 times your own weight pritty good.
What kind of tires do you have and where did you find some to fit the robot and the keyed shaft?
http://www.lightlink.com/wgbrooks/team639/movies/2002_build_1.mpg
And to solve the binding problem when turning (the wheels with no lateral traction):
http://www.team639.org/pics/2002_wheel_on_chassis_2.jpg
BillyGoats
25-01-2003, 14:16
OMG! is the name of this post "how good are your tires" LOL! Tires, jeez when are people going to learn there not the way to go. Well hopefully never =) :cool:
Alexander McGee
25-01-2003, 15:53
Originally posted by BillyGoats
OMG! is the name of this post "how good are your tires" LOL! Tires, jeez when are people going to learn there not the way to go. Well hopefully never =) :cool:
hehe, thats right. why use wheels?
Ashley Weed
25-01-2003, 16:36
Our tires are sweet!..... can't give away details... but I will share soon.... to give a clue.. "they are ideal for the world of the wire ramp!" :D
johnscans
25-01-2003, 17:51
we were pushing our mentor around in low gear and when we stopped he went flying off. i dont think that answers any questions but it was funny
john scans
camtunkpa
25-01-2003, 17:55
What's the big deal....it's not tough, just be creative. I will not disclose any of our traction information at this time, but you'll know when you see us
BBFIRSTCHICK
26-01-2003, 21:00
we got the 3 Spokes ones from Skyway....they have great traction on top of the ramp as well....they were $112 for 4 of them. so they better be worth it
oh guys since our team has a real field ramp, full size made, well its almost complete but what i wanted to say is your bot wont work with tracks at the top of it, it will be to rigid and will slam down at the top also if your bot only weighs 55 pounds, i hope you dont plan on staying on top of the HDPE platform, cause 55 lbs will slide right off, that stuff is slicker then ice and your bot will be pushed right off. Well also there is one more thing i would say about goling up the ramp with your bot but since i want to get you guys thinking about it, whats goign to happen when you put anything weighing over 20lbs going faster then 2ft/sec at a 14degree incline, it wont climb! the bot will slide down the ramp if its going at all relitivly fast, or you prob are braking a rule if it doesnt slide right down or has traction on the grate (hint: you cant have anything go through the open 1"x1"grate squares...)
~Dez
www.team250.org
We just used the skinny gray tires that came with teh kit. ya.. we're trying to stay economical. Maybe we'll cut notches or put studs on them. But that's for later
OneAngryDaisy
27-01-2003, 00:33
Originally posted by Fiziks
We just used the skinny gray tires that came with teh kit. ya.. we're trying to stay economical. Maybe we'll cut notches or put studs on them. But that's for later
you can't put any hard plastic or metal studs on tires this year.. but notches always work- I still remember us frantically filing notches on a couple of our tires a few years ago right before we were due to compete... good memories
Jeff_Rice
27-01-2003, 00:59
Those wheelchair wheels (skinny gray ones) have terrible traction on the mesh. My advice is to use some other kind, such as the large solid rubber ones.
are we allowed to put traction material on the wheels as long as it's not metal filecards or sandpaper?
Matthew936
27-01-2003, 11:15
Can't give away exact details, but with our tires our only concern even on the top is will we have to much traction :) oh and i dare any of you to try and push us off the top, even if we don't build anything else to keep us up there
Its not always a trade off for Maneuverability or traction. Often teams solve this with plastic front wheels that will slide sideways. This works but the plastic wheels don't give the best traction.
Actually as long as the front wheels aren't powered you shouldn't have a problem with what you choose for them. The only wheels that really need to have good traction are powered ones.
Can't give away exact details, but with our tires our only concern even on the top is will we have to much traction oh and i dare any of you to try and push us off the top, even if we don't build anything else to keep us up there
I'd like to see that conserding how a 190pound person with rubber sneakers on still manages to slide around on that plastic stuff.:D
Herrmmm.... well.. there is no arguing that the Tread system is the BEST traction out there,
Actually there are other ways to increase traction but none that would really be usefull in this competition due to the rules constraints. I've read about using vaccuum pumps and making your own wheels to increase traction.
Tracks will not help on the platform.
For all of our purposes, F = (constant) (force normal)
Tracks do help on the carpet and will probably help on the ramp, but the top is no-mans-land. My prediction is momentum will be important, which involves speed up the ramp and not torque/pushing power.
I can hardly wait!
For all of our purposes, F = (constant) (force normal)
It's a whee bit more complicated than that. You could in theory get a coefficent of friction higher than one even though in physics they don't teach you that. Of course your right in saying that momentum is more important because forces involve acceleration and I don't think many bots will be accelerating all the time.
Originally posted by dez250
oh guys since our team has a real field ramp, full size made, well its almost complete but what i wanted to say is your bot wont work with tracks at the top of it, it will be to rigid and will slam down at the top also if your bot only weighs 55 pounds, i hope you dont plan on staying on top of the HDPE platform, cause 55 lbs will slide right off, that stuff is slicker then ice and your bot will be pushed right off. Well also there is one more thing i would say about goling up the ramp with your bot but since i want to get you guys thinking about it, whats goign to happen when you put anything weighing over 20lbs going faster then 2ft/sec at a 14degree incline, it wont climb! the bot will slide down the ramp if its going at all relitivly fast, or you prob are braking a rule if it doesnt slide right down or has traction on the grate (hint: you cant have anything go through the open 1"x1"grate squares...)
~Dez
www.team250.org
Hateto break it to you, but we move t 3-4 fps in low last yr, and we can move up the ramp easily with last yrs robot. It bottoms out, but lwoering the axles takes care of that
Cory
Originally posted by wysiswyg
It's a whee bit more complicated than that.
Hence the "For all of our purposes" ;)
Sachiel7
27-01-2003, 17:07
Hate to brake it to you Matthew936, but with one of our little toys, nobody will be able to push us off the ramp...
Hey, if you're going to VCU, mabie we'll be alliance partners :D
We'll be unstoppable, FWAHAHAHAHAAAAAAAAAA!
Matthew936
27-01-2003, 17:12
Originally posted by Sachiel7
Hate to brake it to you Matthew936, but with one of our little toys, nobody will be able to push us off the ramp...
Hey, if you're going to VCU, mabie we'll be alliance partners :D
We'll be unstoppable, FWAHAHAHAHAAAAAAAAAA!
We are going to Washington, and i have a feeling that we would have no problem pushing you, atleast pushing part of you off
FWAHAHAHAHAHAAAAAAAAAAAA!
;)
Sachiel7
27-01-2003, 19:25
Actually, we are really robust.. It'll be hard to bust us up
We're going to the washington (DC) practice, is this what you mean?
Matthew936
28-01-2003, 09:59
Sorry we are going to Seatle, Washington.
Hey, we're going to seattle too, c u there.
Edward Debler
28-01-2003, 23:29
Originally posted by wysiswyg
..... You could in theory get a coefficent of friction higher than one even though in physics they don't teach you that. ....
Last year Team 217 ThunderChickens used the Neoprene pad material (from Small Parts catalog) on the wheels of our robot.
We determined that the coefficient of friction with the carpet was >1.6. As proof, our robot pulled 220 lbs (horizontal force) at a demonstration conducted during the National competition at Orlando.
Matthew936
29-01-2003, 11:27
Quote:
I'd like to see that conserding how a 190pound person with rubber sneakers on still manages to slide around on that plastic stuff.:D
Who ever said anything about rubber? god i love technology
johnscans
29-01-2003, 15:38
our robot can move around at a farely good speed with our mentor standing on it with only 1 of our 2 drivetrain motors attached. the wheels are performing above and beyond expectations.
john scans
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