Hypothetical Situation - Stairs

[IKE]

A very fast and exciting way would be for a robot that had the ability to shift is CG very high (approximatley 3feet or higher), and then take a run at the platform and let the physics of momentum do the work.
Of course this strategy could literally turn into a trainwreck...

[pandamonium]

id try to create a design that could some how also get the other robots up, maybe a modified ramp bot like 08. Or after it climbs flips down a ramp so the other bots can get up easier

[Cyberphil]

I did some researching on my own of stair-climbing a few months ago and I found some very interesting things.

This one is personally my favorite, and if the modules were made larger, they could potentially climb much larger stairs:

http://www.youtube.com/watch?v=XzKo6KE2H5A

Even something like this is possible in the FRC:

http://www.youtube.com/watch?v=kVEsOxhubFg

The most interesting thing I found was something like this:

http://www.youtube.com/watch?v=uPvj-2KC9G4

But that would be pretty out of the question for FIRST.

But something like this would be extremely interesting to see:

http://www.youtube.com/watch?v=qyVj4...eature=related

I even did some small mental experiments with the mechanics that go into climbing stairs and came up with some pretty interesting ideas.

[Travis Hoffman]

This tank tread system worked very well for us in climbing the platform in 2004 - our arm tilted in the direction of the climb to give us CG advantage when climbing. When climbing down, we kept the arm in the same position and drove in the opposite direction. Very stable.

Game rules (bumper design requirements, ability of appendages to leave base footprint, etc.) may prevent the use of such a method in future "step" games. There are also nagging little weight, cost, and reliability of tread factors associated with this and similar treaded designs.

[rsisk]

Originally Posted by Cyberphil

The most interesting thing I found was something like this:

http://www.youtube.com/watch?v=uPvj-2KC9G4

But that would be pretty out of the question for FIRST.

Why would this be out of the question for FIRST?

[Jared Russell]

Surprised nobody has mentioned Whegs yet They are crazy cool, extremely simple, and can climb obstacles as high as the diameter of the wheel.

http://www.youtube.com/watch?v=F4GF2UFhv8Y
http://www.youtube.com/watch?v=P7UkXh8-cBw

And if you don't want to bump around on flat ground...
http://www.youtube.com/watch?v=lrE8CcquOuQ

[sanddrag]

Originally Posted by Jared341

And if you don't want to bump around on flat ground...
http://www.youtube.com/watch?v=lrE8CcquOuQ

I want to know what extends and retracts these wheels. Anyone have some insight on how this works? It almost looks like there's a rope/string of some sort inside.

[Jared Russell]

Originally Posted by sanddrag

I want to know what extends and retracts these wheels. Anyone have some insight on how this works? It almost looks like there's a rope/string of some sort inside.

I too spent a lot of time looking at the video to try and figure it out. I was hoping I could find a conference or journal paper with more details (since these are university researchers), but I haven't found one yet.

So I can only guess at what approach they took. I could imagine a coaxial shaft inside the drive shaft that moves inward and outward linearly to extend and retract the "whegs" - this would seem to me to be the most FRC-friendly design. There are also possibilities that may involve electrical or pneumatic rotary connectors (slip rings).

A lot of approaches used to achieve variable valve timing in internal combustion engines would seem to be appropriate here.

[Bill_B]

Originally Posted by sanddrag

I want to know what extends and retracts these wheels. Anyone have some insight on how this works? It almost looks like there's a rope/string of some sort inside.

Sounds like the time to learn how to do a patent search. I guarantee it will take your mind off hint #2, hypothetical stairs, and many other things. You might even get good at it, but just in case, set a wakeup call for the 8th.

[Merle]

Originally Posted by Bill_B

Sounds like the time to learn how to do a patent search. I guarantee it will take your mind off hint #2, hypothetical stairs, and many other things. You might even get good at it, but just in case, set a wakeup call for the 8th.

An Estonian patent can be found here: patent link

If you Google the term "ratasjalg" you will find more videos of this wheel-leg device. Ratasjalg appears to be the Estonian term for wheel-leg (Google translates it to "Bike leg").

Merle
Granby GRUNTS #3146 - Mentor
Granby Red Blox - FLL Coach
Granby JrFLL Team Coach

[Jared Russell]

Originally Posted by Merle

An Estonian patent can be found here: patent link

If you Google the term "ratasjalg" you will find more videos of this wheel-leg device. Ratasjalg appears to be the Estonian term for wheel-leg (Google translates it to "Bike leg").

Merle
Granby GRUNTS #3146 - Mentor
Granby Red Blox - FLL Coach
Granby JrFLL Team Coach

Great find. I used this website to translate the text to English (I found a plaintext version of the patent that supports copy & paste here):

The invention belongs to the field of mobile and transport systems, components, and specifically considers the use of different liikurplatvormide, invaseadmete, toys, agricultural and military vehicles at. The invention is sufficiently versatile.
Technique is known as wheeled pedestals, where the bike leg consists of hub, spokes and rim segments, and the hub attached to the spokes pöördemehhanismist, where the spokes are at one end of rummuga wheel pöörlemistasapinnas reversibly and rim segments are connected to the spokes of the second tip reversibly to the wheel axis of rotation parallel to the axle through. Turns to the spokes, they will move the rim segments. This solution is a shortage of small change in wheel diameter of the wheel opening. It also drops an open position, the total load of rods, which in turn reduces the life of the mechanism.

The nature of the invention
This invention is intended to increase reliability and reduce wear of moving parts, Mechanism, and simplifying and reducing the permeability increase. To achieve the objective of the invention will be wheeled cycles, consisting of hub, spokes and rim segments, and attached to the spokes of the hub pöördemehhanismist where the spokes are connected at one end and rummuga rim segments are connected to the spokes of the second tip. Rum, equipped with additional hub of bars and reversible avamissüdamikuga avamissüdamikule reversibly attached at one end. Segment of the rim and the spokes attached avamissüdamiku interim approval from reversibly hub. Foot clutch equipped with additional caster, one of which is bound rigidly avamissüdamikuga rigidly connected to the wheel and the other half feet laagripukiga liikursüsteemil shaft so that the clutch is being applied through a rigid avamissüdamik one side of the coupler and laagripukiga avamissüdamiku fixative. Rim segments are flexible, so that the rim does not exceed the maximum radial deflection of the wheel by foot radius of the opening of the alienation of segments of the rim. Segments cover the outside rim of high-friction surfaces, or well-grip material. Avamissüdamiku slip clutch retainer is necessary. Design has the advantage of less number of moving parts, and more even distribution of forces in the open position. Cycling is easier to automate the opening and closing of the open end of the segment, it is possible to prepare poolelastsena, when open, making it roll even more. Existing wheeled feet, compared to the advantages of this mechanism for easier design and management, as is required of all wheel drive with only one leg segments to move. Ronimisvõime increases, because there is no round the wheel base, which would be in contact with the ground. Instead, the star spokes, between which the segments themselves form the surface of the wheel. This may make shorter segments, because the total length of the leg form with a radius segment. Opening can be manual, electric or other suitable actuator.


Jalas caster wheel is connected to the leg and the positive aspects
The result is a good permeability of the stairs, and levels of

Example of invention

Wheel path consists of a hub, spokes and the rim 2 of the third segment Segments are connected to the spokes of the rim 3 2 reversibly wheel shaft 4 feet by 5 parallel axes. Rum is equipped with an additional hub in a reversible avamissüdamikuga 6, which is connected to the rods 7th 7 is connected to the other end of the rod segments of the third metatarsal Wheel base is equipped with a clutch, one of which is fixed to the disc 8 avamissüdamikuga 6 and 9 are rigidly connected to the second disc wheel shaft fourth leg Laagripukiga 10 of actuator 11 is being applied avamissüdamik 6 rigidly connected via the clutch disc 8 laagripukiga 10th The rim three segments are made flexible so that the maximum radial deflection of the rim wheel does not exceed the radius of the leg by the increment of the rim segments DR 3 opening for smoother movement. Segments of the rim 3 is coated with suitable material from outside the 12, which is great adhesion, and preferably with a good vetruvusomadused. Avamissüdamiku move all segments of the same rotation angle. Columns, which combine the core of the segments, you can use the suspension, which reduces the loads on the deck. Rely on the rim in the retracted position the ends of the segments against each other, forming a single wheel rim. However, the drive force to move the segments to a minimum. The unequal burden of over voltages generated can be used to avoid suspension and flexible elements. If the wheel traction motor torque is greater than the torque necessary to turn avamissüdamiku, the clutch being applied avamissüdamik laagripukiga connected to the shaft and the wheel turning and the engine gets avamissüdamiku position between the spokes. While driving, for example, still holds avamissüdamikku friction or a suitable tool, such as stud or bolt retainer, as is the case with a manual rotating core. Friction prevents the modification of the core position, but the traction motors must be powerful enough to overcome this force.
The drawings are depicted in the six pöiasegmendiga solution. Of experts, it is clear that the principles described may also be prepared by a greater or lesser number of pöiasegmentide wheeled legs.

The untranslated words are probably technical terms that don't appear in a general purpose Estonian dictionary.

[sanddrag]

When I was a kid I had a battery-powered toy truck that had claws that would automatically pop out of the wheels any time an obstacle was encountered. It was pretty cool, and really helped it move along through rough terrain.

[Chris Fultz]

http://www.cyberblue234.com/images/p...04/robot/3.jpg

This is a link to our 2004 robot. It had heavy duty tank treads. The treads gripped the edge of the platform and pulled the robot up.

These were functionally good, but very heavy and required a special drive "cog" on the inner tread.

However, they were practically indestructable - they had a kevlar layer in them and we actually designed for bomb finding robots.

Several other robots used similar designs of treads to make the step up.

[Cyberphil]

Originally Posted by rsisk

Why would this be out of the question for FIRST?

By out of the question, I did not mean that FIRST teams could not do this. I am sure that FRC teams could do this actually!

What I meant was the usefulness of this. The only thing this (What I guess you would call a drive train) is made for is climbing stairs. This could potentially be used on a bot, but the usefulness of it is what I would question.

Now after saying this, I know the 2011 game is going to consist predominately of stairs, and some team will come up with this design and make it to Einstein.

That would be just my luck, and I would love every second of it!

[Jared Russell]

Originally Posted by Cyberphil

What I meant was the usefulness of this. The only thing this (What I guess you would call a drive train) is made for is climbing stairs. This could potentially be used on a bot, but the usefulness of it is what I would question.

Actually, if properly configured, this design allows for omnidirectional movement (similar to mecanum drive) as well (http://www.youtube.com/watch?v=1uynm...ature=related).