Hypothetical Situation - Stairs

[BrendanB]

Originally Posted by Chris is me

You shouldn't be buying*, building, or designing anything before Kickoff.

*with the probable exception of tools, supplies, raw materials, etc.

Why not? I would love to be prototyping a tank drive in the off-season even though it is almost over. Off-season is THE time for prototyping new ideas or mechanisms you are unfamiliar with so come build season you have knowledge that you can build off of.

[Rob Colatutto]

Originally Posted by Teched3

If I remember the game correctly, WPI (Team 190) had a great platform climber, went around a goal obstruction, and hung on a bar, all autonomously. Can't wait to see the new game. Speculation is generally fruitless, but can be fun for some.

The 190 robot also had across it, 4 sets of wheels, instead of just two. As it climbed up, parts of the robot were over hanging off the platform, and the robot could be supported by wheels in the center of the robot.

Also, this design worked well when it was able to get up on the platform in auto. I saw a few matches they were in where they did not make it up onto the platform. This posed a problem, as the robot could not turn well.

Just remember, many great designs have also had a major drawback.

A perfect example of this is finals match 2 from the championship of 2002. SPAM 180 beat 71 to the center goal, and knocked them out of the way. Without the goals secured to itself, not all that much they could do. http://www.thebluealliance.net/tbatv/match/2002cmp_f1m2

Not to move this off topic, but just remember there are always tradeoffs to be made. How you deal with the game elements and field is up to you.

[Chris is me]

Originally Posted by BrendanB

Why not? I would love to be prototyping a tank drive in the off-season even though it is almost over. Off-season is THE time for prototyping new ideas or mechanisms you are unfamiliar with so come build season you have knowledge that you can build off of.

Edited my post to clarify.

[alicen]

what about something like:
http://www.youtube.com/watch?v=a0NFrA-Nx4Y
prototyping that kind of drive train would even be useful for that fabled water game

also, for those wanting a real challenge, try this method:
http://www.youtube.com/watch?v=kpfjnqaFwtU&NR=1

[Karthik]

Originally Posted by apalrd

Look at robots from 2004. They climbed steps very well.

Simbotics (1114): They had four wheel pods (two crab pods and two casters) each with a pneumatic piston. They would lift all of the pistons, then run into the platform. Sensors on each pod would lift it as it hit the platform.

Originally Posted by EricH

Tank tracks: Outback Manufacturing has a kit for those, but most teams make their own with varying degrees of success (the Triplets in 2006) and unsuccess (any robot that throws more than one or two in a season). They'll work for stairs, but I wouldn't recommend them for flat floors necessarily.

Although we were relatively successful with both the complex wheel pods of Simbot Simon in 2004 and the tank treads of Simbot Beckham in 2006, neither solution was chosen for pure climbing ability.

In 2004, the reason we went with with the independent lifting wheel pods was because we felt it was the best way to climb a 6" step, while using a swerve drive. If we weren't already committed to swerve drive, there's no way we would have gone down this road. This was just way too complex of a solution for a problem that could be handled in a much more conventional way.

In 2006, our use of tank treads had very little to do with climbing the ramps that were on the field. We went with the treads because we felt we could get more traction by taking advantage of the longer contact patch between the tread and the carpet. Granted, this does seem a bit odd considering the equation for traction has no surface area component. When you're dealing with two surfaces that interlock in the way carpet and roughtop tread do, the traditional model for evaluating traction doesn't exactly apply. Regardless, we chose treads because we wanted that robot to be immovable, the benefit of climbing the ramp was an added bonus. Again, the complexity, maintenance and cost could not have been justified just for climbing when a much simpler solution could have sufficed.

So, I don't have any groundbreaking suggestions for innovative stair climbing devices. However, I can say this: If you are going to go with a complex design like the ones discussed above, you better make sure the extreme design costs are justified by the game benefits. Typically the best way to justify these costs for a function is to make sure you get multiple points of utility out of them.

(And if you didn't bother reading all of that, here's the synopsis: Keep it simple!)

[davidthefat]

http://www.societyofrobots.com/robot_asme.shtml
Now, depending on the rules, this kind of robot might be possible. As long as the 3 inch rule is not in this year's rules, it should work great.
http://www.societyofrobots.com/robot...t_monkey.shtml
Now I am not sure if this is possible with the bumpers in the way, but his has honorary mentions.

Try this:
http://www.youtube.com/watch?v=67CUudkjEG4

[Hawiian Cadder]

if i was on a rookie team the way that i would do this is an 8wd with the 10 inch kit wheels. the middle two being drop center and rubber traction, the back one being a slick wheel, and the front being a 10 inch IFI wheel, i think the IFI wheel would hold up better with impacts and has a higher traction coefficient. 10 kit wheels will not fit in the 38 inches that we are given but if they are layed out like this:

XXXXXXXX.......................XXXXXXXXXX
..........XXXXXXXX.XXXXXXXXXXX


with the chain in between the two rows of wheels, then it would work.

[apalrd]

1. The wheels you speak of are probably the 8" AndyMark wheels, either the FIRST, FIRST slick, Plaction, etc. and the 8" IFI wheels

2. The IFI wheels use the same tread as the AndyMark Plaction wheels (Actually, they can use either, the difference is minor between wedgetop and roughtop, and you can get both from AndyMark or IFI, but the Roughtop tends to have more usable life).

3. Why not just use 8 Plaction wheels (or other wheels with roughtop tread) in a dropped center 8wd?

[czeke]

Also, keep in mind, that you could modify some snowmobile treads. Team 1091 did that, last season, and we had some excellent success with traction and manueverability. We could easily navigate over the bumps, and by gearing down, we lost some speed, but we weren't pushed around.

[BrendanB]

Originally Posted by Karthik

In 2006, our use of tank treads had very little to do with climbing the ramps that were on the field. We went with the treads because we felt we could get more traction by taking advantage of the longer contact patch between the tread and the carpet. Granted, this does seem a bit odd considering the equation for traction has no surface area component. When you're dealing with two surfaces that interlock in the way carpet and roughtop tread do, the traditional model for evaluating traction doesn't exactly apply. Regardless, we chose treads because we wanted that robot to be immovable, the benefit of climbing the ramp was an added bonus. Again, the complexity, maintenance and cost could not have been justified just for climbing when a much simpler solution could have sufficed.

Did you have any issues with the tank treads coming off while in use or have suggestions that you guys used? I noticed that is was a common issue for team 195 and during a few drive train lessons have heard that treads have problem staying on track. Your 1114, 1503, and 1680's robots are some of the top tread robots in my honest opinion.

[davidthefat]

I have a question: what kind of legal servos are able to support a 100+ lb robot? Would pneumatics or other parts be necessary to support such a robot?

[,4lex S.]

Go go gadget Packbot?

[James Tonthat]

Originally Posted by davidthefat

I have a question: what kind of legal servos are able to support a 100+ lb robot? Would pneumatics or other parts be necessary to support such a robot?

I don't understand your question. What kind of application are you using to use them in? Which robot are you referring to?

[apalrd]

Originally Posted by davidthefat

I have a question: what kind of legal servos are able to support a 100+ lb robot? Would pneumatics or other parts be necessary to support such a robot?

The Answer:

ANY

If you gear it enough


But id be faster if you used a more powerful motor such as a CIM or Fisher-Price.

[Jeremy Germita]

Originally Posted by davidthefat

I have a question: what kind of legal servos are able to support a 100+ lb robot? Would pneumatics or other parts be necessary to support such a robot?

Perhaps a gearbox, geared for torque, with an encoder on the output. You could use a P loop to control the position.

You could use a ratchet device to support the robot most of the time, only releasing it when you want to change postion.