Hypothetical Situation - Stairs

[Dave Scheck]

I know this doesn't address the OP's original question, but to add on to what was said here

Originally Posted by apalrd

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.

We had a similar solution, except it was just front and back instead of 4 independent modules like they did. We had 8 light sensors that we used to detect where the robot was relative to the platform and raised/lowered the modules accordingly. It worked great, but in practice the time that it took to raise the modules wasn't as fast as we had hoped (the goal was to be able to drive on without slowing down)

Check out our Encore promo video from that year to see more details.

Again, that was a different challenge with only a single step to deal with.

[BrendanB]

As a mentor of one of those rookie teams who will most likely be using the kit frame unless CADed otherwise, I would recommend designs such as 190's 2004 robot. Or I would really like to try 1276's off-season prototype.

190: http://www.youtube.com/watch?v=Q5nnGGRi-94

1276: http://www.chiefdelphi.com/media/photos/35982

[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.

[EricH]

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.

They went up the 2" stairs, and intentionally built narrow to go around the goal. I remember that part of their robot was a piece of laminated paper to reach over a line and "straddle" it so they'd be in position for the stairs.

I might try 330's approach: oversized rear pneumatic tires (12") with an angled front and 6" wheels to lead up the step.

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.

[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.