pic: Team 148 - Robowranglers 2010 - Armadillo

[Chris Fultz]

Originally Posted by Kims Robot

Maybe John or Paul could post a sample schedule that they follow...

They did, it is in the Design Process paper.

[OathKpr95]

Dear god. Im actually fearing for the well-being of my robots life right now.

Then again I should expect nothing less from the team who made that absolute beast of a robot that we ocasionally had to compete with in last years Dallas regional. I look forward to seeing teh mayhem that your team will cause when we meet again in dallas .

[pilum40]

Whoa....our bot is primitive in comparision. We're concentrating on keeping things simple, running consistently, and being able to move/support our alliance teams this year by good defence, going through the tunnel/over the hump, and making those "garbarge goals" whenever possible. In comparison to y'all's bot...we're looking pretty lame.

See you in Dallas! We're from Summit International Prep-Our bot's name is GAGABot! Hope it doesn't turn into gaga-me-bot!

[umangv620]

so epic. good job 148!!

[O'Sancheski]

that bot is so awesome... i just can't believe how awesome that robot is... it is just amazing

[VanMan]

This is great. I'm loving the video. What I fail to understand is how can all of this be done in 6 weeks? Students have school to attend, mentors have jobs to work. The drive base alone looks like it would take a team at least 6 weeks. And they were probably done by at least week 4 so they could debug and practice. I just don't understand how there are enough hours in the day to make a machine that is this amazing. This is truly amazing. You all better do well now that you have such a neat bot.

[ouellet348]

calling winner of nationals right now, great job guys, best robot I have seen by far

[falconmaster]

Totally Awesome!

[Karibou]

Originally Posted by Kims Robot

BINGO... ie DO NOT TRY THIS AT HOME!!! If any regular team spent 3 weeks prototyping, they would be in a world of hurt because their parts would never get finished in time to even build a robot. I know this because in 2006 1511 spent that 3 weeks prototyping, and finally abandoned all prototypes and went with a concept we figured would work, no design, we just built it... fortunately we survived, but we most certainly did NOT come out with an elegant machine, and did not have enough test or programming time. Dmentor hit it on the head, its that they have trained their students and team so well on design, and have great manufacturing support and capability, and THAT allows them to prototype for that long to come up with the best solutions. Until you get to that level of engineering process, in my mind you CANNOT spend 3 weeks prototyping or you will shoot yourself in the foot.

Seconded. We spent 3 weeks prototyping last year (some things were designed during the process, though), and we barely got a somewhat-working robot in the bag. Even then, we still made a lot of tweaks - particularly in the code - at Kettering, which was our first competition. We had no practice time before bag, which, while unfortunately normal for us, is definitely something that would hurt a lot of teams. We managed to catch up with ourselves at Detroit, but Kettering was not a fun experience. Don't do it, folks!

[Arefin Bari]

I just checked to see if IFI's website have the kicker in stock...

... they don't. =(

[sanddrag]

Originally Posted by Arefin Bari

I just checked to see if IFI's website have the kicker in stock...

... they don't. =(

Yeah, we got the last one. j/k

[Lil' Lavery]

So I've had a couple days to salvate over this robot/piece of art, but I do have a couple questions.

First off, what's the purpose of the pole that extends beyond the hanging mechanism? Is that to aid with alignment?


Secondly, what prompted you to go with the dropping center omni wheel set-up, instead of just having the four articulating drive pods with mecanum wheels instead of omni (similar to what is shown on pg.4 of this paper)?
The only advantages that's obvious to me of your configuration is it's likely cheaper than buying/manufacturing mecanum wheels and you save some weight and money by using one fewer gearbox (as you can drive both sides of the robot together, but also have to add another one in for the center omni). But otherwise it seems like you're using an additional motor and point of articulation for no real benefit over a similar concept using mecanum wheels.
Also, are you using any sort of closed-loop control to try and account for uneven forces between the forward/reverse (where you have four motors operating) and lateral directions (where you only have one)?


Overall, it's obviously an absolutely gorgeous machine that I certainly hope I get the opportunity to examine at greater detail.

[Travis Hoffman]

Originally Posted by Lil' Lavery

First off, what's the purpose of the pole that extends beyond the hanging mechanism? Is that to aid with alignment?

That was my thought - it also adds to the aggressive appearance of the robot.

What about an aid to self-right if they tip over - as if that would happen.

Maybe they can turn it into a confetti cannon - that surely must be the latest "major redesign" mentioned on John's Facebook.

[JVN]

Originally Posted by Lil' Lavery

First off, what's the purpose of the pole that extends beyond the hanging mechanism? Is that to aid with alignment?

The pole serves two main purposes, you've got the first one right. The driver can "slap" our pole onto the tower and then drive forward until the claw latch is engaged. We experimented with all sorts of "docking aids" but this simple pole worked pretty well.

The second purpose is to extend the "claw" for the purposes of self-righting the robot.

-John

[JVN]

Originally Posted by Lil' Lavery

Secondly, what prompted you to go with the dropping center omni wheel set-up, instead of just having the four articulating drive pods with mecanum wheels?

We refer to the 5-omni setup as something called a "Slide Drive". When you combine a slide drive with 4 drop down traction wheels you get what we're calling "Nonadrive" (not Nano Drive as Mike Copioli seems to think...)

Why do we use a slide drive?

Here is the quantitative part:
1. This drive allows for the front and rear wheels to be "linked" without needing a ball differential or anything like that. If one wheel comes off the ground, you still have the full power available on the other wheel.

2. We have 4 motors worth of power pointing forward/backward at all times. With a Mecanum drive, you only get part of this. (The mecanum drive has better side-side power than our 1-CIM, but we don't care.

3. The "slide drive" part of the Nonadrive is 100% intuitive to control, with ZERO programming. This is not meant to discount the efforts of our incredible programmers (148 and 217 have some GREAT ones), but the slide drive can be fully utilized with default code, and its control would be identical to Halo, Call of Duty or any other FPS videogame.

Here is the "not so quantitative" part:

This will be a controversial statement...
In all of my competition robotics experience I have never encountered any drivetrain (swerve, mecanum, or omni) that drives as well as our slide drives. Maybe it has something to do with a lack of programming. Maybe it has something to do with a driver's mental block. I don't know. What I do know is that you put a slide drive in the hands of a good FRC driver, and they'll be almost immediately doing maneuvers that make your head spin.

Before you knee-jerk and reply, remember who you're talking to. We understand design tradeoffs. We understand your value propositions may be different than ours.

Honestly, I expected more people to ask us "Why the heck did you do THAT instead of just doing a swerve or mecanum drive?" My answer is... "If you built one and drove it, you'd understand."

Originally Posted by Lil' Lavery

Also, are you using any sort of closed-loop control to try and account for uneven forces between the forward/reverse (where you have four motors operating) and lateral directions (where you only have one)?

Nope. The slide wheel is positioned near enough to the CG that she moves sideways almost straight as an arrow. The same can be said for forward and reverse, even without the traction wheels down. No complicated control needed. For testing (before we had any of the other electronics wired up) I took a VEX PIC Microcontroller from inventory, hooked the Victors up and we drove it with default code. Really.

-John