Just how high can you climb?

[FatNick]

well i just wanted to know if any of you were cuoris of what your robot could do well a few of the engineers over here at spam got kinda crazy the other night. we wanted to se just how much of an angle our bot could climb well we found out 60 degrees is pretty steep but no match for fluffy. wonder if any one else played with any thing like that or if any one has played with just how much thire bot can really move.

[OneAngryDaisy]

I think most of it is related to the robots' center of gravity.. Tall robots would likely not be able to do extreme slopes..

Our last two robots- they propbably could do pretty well as both are under 2 feet tall and have great traction.. we'll have to try that- thats an intriguing idea

[mtaman02]

dorothy can't do much climbing since her wheels arent that exposed and they're metal with plastic treading on them

wilma on the other hand was built like a tank and well she can roll on over anything her slope is probably 20 - 30 degrees

[Alavinus]

Our robot would probably only manage a 30 degree angle climb. While our robot was not tall, we have our tracks recessed 2 inches into the bot, and with about 1 inch on ground clearance, our frame would hit the ramp. (If you were at the Md state fair and remember a robot hooked on a goal with a ball lifting the front wheels off the ground- that was us)

[Jeff Waegelin]

We haven't tested it, but our bot could probably climb a pretty steep angle. We have a very low center of gravity (our bot is only about 2.5 ft tall) and our treads on our wheels have ridiculous traction (almost too much to turn).

[Stephen Kowski]

Actually in the an auditorium wherre they had kinda wide stairs we started climbing stairs. Even have a video of it somewhere....we put our end effect from a previous robot pushed up our front wheels and literally walked up the stairs.

[DaBruteForceGuy]

We have tremendous pulling power. The mainly comes from our using the 2 chipuas and 2 drillas at the same time. BUT the reason for our optimal usuage of all the power is our treds, which (when on the ground) give us upwards of 200 sq. inches of traction. So, we not only would be able to stay on the incline, but i think that we could prolly push up with our stregnth
maybe i'll try it.

[Bduggan04]

Originally posted by DaBruteForceGuy
We have tremendous pulling power. The mainly comes from our using the 2 chipuas and 2 drillas at the same time. BUT the reason for our optimal usuage of all the power is our treds, which (when on the ground) give us upwards of 200 sq. inches of traction. So, we not only would be able to stay on the incline, but i think that we could prolly push up with our stregnth
maybe i'll try it.

How tall was your robot, or more importantly, where was the center of gravity? The ability to climb a steep slope doesn't depend signifigantly on torque. Traction is a function (If I remember right) of the amount of weight and the tangent of the max angle the traction material keep from not sliding.

[Matt Leese]

Originally posted by DaBruteForceGuy
We have tremendous pulling power. The mainly comes from our using the 2 chipuas and 2 drillas at the same time. BUT the reason for our optimal usuage of all the power is our treds, which (when on the ground) give us upwards of 200 sq. inches of traction. So, we not only would be able to stay on the incline, but i think that we could prolly push up with our stregnth
maybe i'll try it.

Traction has (almost) nothing to do with surface area. Traction is directly proportional to the normal force of an object (F=uN). While your treads probably had a high u (mu), the contact area did not increase your traction.

I do say almost nothing to do with surface area because traction will increase in cases where you actually have the one object mesh with the other (think of the brushes that were used effectively by some teams this year). In those cases, area coverage does matter. In most cases, it has little to do with the traction of a given robot.

Yes, the whole idea is counter-intuitive. This is, however, how it works. Surface area does make a difference for turning however. But it's fairly unrelated to the topic at hand.

Matt

[Madison]

Originally posted by Matt Leese
Traction has (almost) nothing to do with surface area. Traction is directly proportional to the normal force of an object (F=uN). While your treads probably had a high u (mu), the contact area did not increase your traction.

I do say almost nothing to do with surface area because traction will increase in cases where you actually have the one object mesh with the other (think of the brushes that were used effectively by some teams this year). In those cases, area coverage does matter. In most cases, it has little to do with the traction of a given robot.

Yes, the whole idea is counter-intuitive. This is, however, how it works. Surface area does make a difference for turning however. But it's fairly unrelated to the topic at hand.

Matt

Matt, the type of belting material we used lends itself as a good example of why is *almost* doesn't matter. It does have a texture that meshes well with the carpet. So, in our case, the large surface area became important because it decreased the potential for slipping of the belts.

You saw it, didn't you?

Anyway, that's why we decided to go with such a large area of belting. While our gearing nor our N*mu were amazing, I think that our belts helped us harness the available torque and transfer it to the carpet better than many other teams

[Ian W.]

also guys, we're forgetting the one rather important thing. the robot can't go on anything other than a straight plane, considering that even with the treads out, the frame would smack into the angled plane before the treads would hit it (unless you did some crazy curved thing that slowly increased the angle, but that's too much to think about). so yes, *if* we could get the robot on the angled plane to begin with, we could probably do pretty good. it's just a matter of getting it on the angled plane in the first place .

[DaBruteForceGuy]

Originally posted by Bduggan04
How tall was your robot, or more importantly, where was the center of gravity? The ability to climb a steep slope doesn't depend signifigantly on torque. Traction is a function (If I remember right) of the amount of weight and the tangent of the max angle the traction material keep from not sliding.

My Teamates were nice enough to chime in and respond to the other questions, (thanks Mike!). But this is simple to answer, if you havn't see "El Toro", we have an extreemly low center of gravity. We are actually about 1 1/2' tall and have a ground clearance of less than 1/4" (which is why it would be hard to get up the incline).
Yea, if we were to go up an incline like that i was thinking that we would have to set the bot already on the incline.

[Gadget470]

would be interesting to see 71's walker start crawling up a steep slope.

[RebAl]

Remember this FF = mu FN and mu=Tan of the angle of inclination FN = mg cos of the angle of inclination, so we can all figure out who has the most friction

#%#%#%#% whoops, i mean dern AP physics c