22-01-2011 00:39

RMS11

Re: pic: Final 2011 Drivetrain

Is this a teaser? Can we get some explanation? Are the wheels to be omni in the future?

22-01-2011 00:42

nighterfighter

Re: pic: Final 2011 Drivetrain

It looks really small. Really small...

22-01-2011 00:54

Andrew Remmers

Re: pic: Final 2011 Drivetrain

No gearboxes?

22-01-2011 00:57

GGCO

Re: pic: Final 2011 Drivetrain

Huh....

22-01-2011 00:59

ttldomination

Re: pic: Final 2011 Drivetrain

Each CIM is about 4.3" long. Seeing as that model looks can it hold 4-5 CIMs end to end, I don't think that thing is more than 20" long.

- Sunny

22-01-2011 00:59

Kevin Sevcik

Re: pic: Final 2011 Drivetrain

You think that's small? If those are CIMs, that thing is pushing right up to the edge of 28" wide, actually. I'll grant you it's not the full 28"x38", but I'd never call that a small robot.

22-01-2011 01:10

poohbear

Re: pic: Final 2011 Drivetrain

Hey comrads!

Here's our team's final design for our first drivetrain ever and its pretty innovative if i say so myself

-the body is milled from a solid block of 7071 aluminum (with our sponsor's five axis mill) to retain the maximum structural strength.
-the wheels are decagons instead of circles. NOW can we squeeze in more than tangential contact every tenth of a rotation, therefore we get more traction.
-the wheel formation allows for no "getting pushed around" and great defense. We might be the rookies, but thanks to our ingenuity, we're not going to get bullied on the field
-these four wheels are directly driven by CIMs so we can zip across the field at 154 fps according to JVN Design Calculator (great tool by the way guys).
-the bot fits in a 26x26 square. its octagonal shape allows for surface area for electronics.

I know its pretty good, but what are some design tips you veteran teams might want to bestow upon us?

P.S. The manipulator is coming soon with just as much innovation as you see here. Watch out for team 3815!!!

P.S.S. We would like to thank our professional mentors for their wisdom and guidance in designing this beastly beauty.

22-01-2011 01:15

AllenGregoryIV

Re: pic: Final 2011 Drivetrain

Welcome to CD, that is a pretty good first post if I have ever seen one. I thought 15.4 fps was going to be fast this year but you guys are taking this to whole different place (value).

22-01-2011 01:19

Joe G.

Re: pic: Final 2011 Drivetrain

-Frame milled from solid...um...wow! How long is that operation going to take, and how much does that block of aluminum cost??
(seriously, check this, if the block is over $400 market value, you may run into trouble)

-Has the wheels/wheel formation been prototyped? I'm intrigued, yet skeptical of how well it will work. Do the corners of the wheels have low-traction material? This formation typically uses omniwheels for multi-directional motion, and I'm not sure how it will work with traction wheels.

-Again, you may want to prototype and see just how much traction you gain from decagon-shaped wheels, and whether it's worth the bumpy ride.

-Direct drive from CIMs...That's not quite how it works. Gear reductions add torque, and a free-spinning CIM does not have close to enough to move a robot effectively. You may want to look at JVN's calculator again, and see how much torque it will take for a 6-8" wheel to effectively acccelerate 150-ish pounds of robot. The fastest I've ever heard of a robot moving is 18-ish feet per second. Also, consider the drivers. Do they have the reaction time to effectively control a speedy robot? Might slowing it down, in some ways, speed you up?

22-01-2011 01:27

Nuttyman54

Re: pic: Final 2011 Drivetrain

Wow...just...wow. I thought fast would be good but, at those speeds you should be able to use the Lorentz Contraction to get away with a larger manipulator into the 84" cylinder (the refs will never be able to tell!). This is sheer brilliance! Have you considered the possibility of using the Picard Maneuver in match play?

22-01-2011 01:28

Hawiian Cadder

Re: pic: Final 2011 Drivetrain

woah, that means it will cross the field in 1/3 of a second, if you can effectively make a frame like that i like it. also without gearboxes you will be pushed around quite a bit.

22-01-2011 01:48

Hawiian Cadder

Re: pic: Final 2011 Drivetrain

actually this would work, you just need to control it with a melty brain.

http://www.spambutcher.com/meltyb.html

22-01-2011 02:52

SirTasty

Re: pic: Final 2011 Drivetrain

um... wow... where to begin...

Brace yourself, this post is going to be extremely critical, but you will thank me for it later. Take it from a four-year FRC team member and a design/strategy specialist, there are like nine thousand and one problems with this drive train that will make it all but unusable on the field. I'll start with your bullet points.

This is almost definitely outside of the budget allowed within the rules and is also a huge waste of money and resources. Frankly, I am a bit dumbstruck that your sponsor is willing to commit their five-axis mill to this kind of project.

I have no concrete criticism of this one, but suffice it to say that I am extremely skeptical. Wheels are circular for a reason, if decagons worked better, some automotive specialist would have noticed in the last hundred years or so. Of course, robots are not cars, so if you really think you've hit on something here, I would create a prototype to see what happens, but I am 99% certain that this will not be effective. I think the most likely result is your motor does not have enough torque to turn the wheel.

Are you referring to the 45 degree angle "holomonic" wheel configuration? Every year we see a team try this. Traditionally it's done with omni wheels, but I've seen it done with regular traction wheels. It never works. The traction from the "front" and "back" wheels gets in the way of the "side" wheels, and all you can do is spin. You can use omnis to fix this, but you end up with no traction. If you want omnidirectional steering, take four hundred bucks you would spend on that aluminum block and invest them in a good set of mecanum wheels instead. Better yet, if you have access to the kind of machine shop that lets you use a five-axis mill, you probably have the ability to make a legitimate swerve drive. Or, since you're a rookie team, you could go with a traditional four-wheel or six-wheel drive. Anything but this mess.

Either you missed a decimal point (or two?) or you're doing something very wrong. This number is completely ridiculous, throw it out (btw, I rolled on the floor laughing when I read the comment about the Picard maneuver). Seriously. The most likely result is your motors stall from not being able to rotate your (decagonal) wheels. Particularly without gearboxes. Seriously, get some gearboxes.

No problem here, moving on.

Here's a tip: don't try anything crazy in your first year. Innovation rocks, but if there's a traditional way of doing something, the reason "everyone else is doing it" is because it works. Learn from historical teams' mistakes, not your own. One should never be afraid to depart from the norm, but should never do it without careful thought (which clearly wasn't given here). You have to really understand the rules before you know how to break them.

Of course, there's a chance that you'll just ignore me, in which case I hope I don't end up on an alliance with you. Just remember that Dolan from 2374 warned you.

Anyway, that whole post was very rude (inb4 "you're trampling creativity"), but you really needed to hear that before you wasted all of that time and money. Now you're out a third of your build season, it's time to think about reprioritizing.

22-01-2011 03:40

JVN

Re: pic: Final 2011 Drivetrain

Wow. I don't know if this is a joke, in which case I just wasted my time typing up the following post. In the rare event that it isn't a joke, I'll describe some motor loading for you. If nothing else this post is a good summary of what goes on when a robot accelerates (or catches fire, whichever comes first).

Short version:
If you build this thing, it won't work at all. My spreadsheet should have some kind of "are you serious?" warning built into it...

Please review this presentation immediately:
http://www.chiefdelphi.com/media/papers/2429

JVN's "in a nutshell" description of motor loading and acceleration:
Motors have limited power, this means for a given amount of load they can only move so fast. The less load they have on them, the faster they move. At some load they won't move at all (stall), and at no load they have a maximum speed they spin at (free speed). They draw current from the battery depending on how high the applied load is. If the current drawn is too high, the breakers will trip (or the motors will catch fire, whichever comes first).

When a robot is accelerating, at the instant it starts moving, it isn't moving -- the motors output their stall torque. Drivetrains typically increase this torque with a speed reducer/torque increase geartrain. This torque is then applied on the ground as a force which is used to accelerate the robot. As the robot accelerates the robot starts moving which means the motor spins faster which means the torque output decreases (the motors speed & torque are linear, remember?). So why does this matter?

With CIM motors, the stall current is much higher than the capacity of the 40amp circuit breakers. If you try to accelerate with too little gear reduction (i.e. the drive is too fast) or with NO gear reduction as you show, the output force of the wheel on the ground will cause the robot to accelerate very slowly. If this acceleration is too slow, the motor will be very high on the torque curve for a long period of time, which means it will be drawing lots of current for a long period of time, which means it will catch fire (or pop the breakers, whichever comes first).

The moral of the story... your robot would take approximately the length of an airfield to accelerate to top speed, which it never would because it would pop the breakers or catch fire (whichever comes first).

Ohh... not to mention that if you ever try to get into a pushing match the wheels act as brakes on the motor and if your gearing doesn't reduce the torque load enough it will also cause the motor to draw too much current and cause the robot to catch fire or pop the breakers (whichever comes first).

Ohh... not to mention that you have traction wheels opposed at 90-degrees from each other. So in order for the robot to move in any given direction it needs to slide a set of high traction wheels sideways across the carpet... which of course it needs torque to do, but since it has no gearing it will probably just catch fire, or pop the breakers (whichever comes first).

Physics is such a pain in the butt when it gets in the way of innovation, isn't it? I guess true innovation is when you can actually harness physics to do what you want. Heck -- that sounds suspiciously like engineering.

-John

PS - Expert tip: robots work much better if they are 9-sided. 100% of 9-sided robots have won World Championships. Add an extra side, quick! True story.

22-01-2011 03:59

Cory

Re: pic: Final 2011 Drivetrain

This has to be a joke. Conservatively, that would be a NINE HUNDRED POUND block of aluminum. 7075 is about $7-10 per pound. That's a $6000-9000 block of aluminum. No sponsor is stupid enough to waste that kind of material. This also ignores the fact that there is no such thing as 7071 aluminum. The frame would also be substantially weaker than a properly constructed welded tube or sheet-metal chassis.

Basically...obvious troll is obvious.

22-01-2011 04:37

SirTasty

Re: pic: Final 2011 Drivetrain

In that case, I must leave a well-deserved,

22-01-2011 05:34

114Klaatu0x72

Re: pic: Final 2011 Drivetrain

Decagon wheels mounted directly the cims will be the drive train of the future.

22-01-2011 09:56

MrForbes

Re: pic: Final 2011 Drivetrain

Very nice design! Robotics is supposed to be fun...this is definitely fun

22-01-2011 10:00

Tom Ore

Re: pic: Final 2011 Drivetrain

I agree that this is good fun - most likely this is someone's practical joke on CD. If not, one consolation is that you learn more from failure than success.

22-01-2011 10:14

Sean Raia

Re: pic: Final 2011 Drivetrain

Consider the following: his name is poohbear, this was his first post, his location is "the dirty south", and he claims his robot can go 105 miles per hour... this all sounds pretty legitamate to me.

22-01-2011 10:39

poohbear

Re: pic: Final 2011 Drivetrain

I have to agree with this one. You all will see!

22-01-2011 13:02

ratdude747

Re: pic: Final 2011 Drivetrain

i smell troll...

22-01-2011 18:11

AlexH

Re: pic: Final 2011 Drivetrain

So its about 865 amps to spin the wheels (assuming 6" wheels and a 120lb bot) and victors are rated at 40 amps. That comes out to 22 victors per side times 4 (22 victors per each motor) is 88 victors and that comes out to $7920 excluding shipping. Are you sure you want to spend almost 8 grand on ESC's?

Also the CIMS stall current is 133 amps so you might want to find a better way to drive your bot because 865 is 6 1/2 times the rated stall current of the CIMs

22-01-2011 18:49

Trent B

Re: pic: Final 2011 Drivetrain

Forget about the number of victors needed. You have a 120 amp kill switch

22-01-2011 19:54

basicxman

Re: pic: Final 2011 Drivetrain

Agreed, but my lord this thread was funny. I'm giving the poster a rep.

22-01-2011 20:07

Thermal

Re: pic: Final 2011 Drivetrain

Great design! But, there is one small issue. You have no fillets for strength in your design.

Add some fillets and you'll be indestructable! Also, go with 9 sides, because like JVN said, nonagonal robots have a 100% winning percentage.

22-01-2011 22:19

Joe Schornak

Re: pic: Final 2011 Drivetrain

After viewing this robot design, and the request for veteran tips within, I decided that it would be a good idea to put together a robot design guide, so that we can all learn to design effective robots in the future.

BEHOLD! Joe Schornak's Robot Design Guide

22-01-2011 22:46

nighterfighter

Re: pic: Final 2011 Drivetrain

Freshmen with drills and jigsaws ARE a cheap alternative to a 5 axis mill though!

22-01-2011 23:28

DavidGitz

Re: pic: Final 2011 Drivetrain

This is pretty awesome, and loving the Picard Maneuver reference. A small part of my mind wonders though, if this poster wasn't trolling. Then I would feel bad, on a couple different levels.

22-01-2011 23:44

Bill_B

Re: pic: Final 2011 Drivetrain

Probably planning on milling the bumpers out of solid pool noodle stock, too. Ever wonder how they drill that hole down the middle of pool noodles?

23-01-2011 17:05

Andrew Y.

Re: pic: Final 2011 Drivetrain

JUST INCASE THIS IS N OT A TROLL JOKE

Hey Poonbear, my name is Andrew and I am a mentor for the Westminster School's Robotics team, team 2415, the WiredCats. I looked up your team number and I see that your team is from North Forsyth County. My team is located in Atlanta and are not too far from you guys and that you guys are rookies.

I see that there are a few design flaws (and boy do I wish that we had a 5 axis CNC mill) and we are always looking to help other teams whenever we can. If you would to set up a meeting, some students as well as myself can make the trip up there and help out some if you would like.

But remember, time is of the essence in this situation, we dont have much time left in the season but I know that if this is not a joke, we can really get something workable together.

Thanks and good luck in the season,
Andrew

23-01-2011 18:04

poohbear

Re: pic: Final 2011 Drivetrain

Thank you bunches Andrew Y.

Its nice to have a helper after such criticism and mockery

I have made a few major changes to the drivetrain since posting this though...

- With the help of our mentors, we have designed a magnificent two-speed (8fps & 16fps) crab-drive instead of the previous traction drive. We think this will handle this precision-based game a little better. Sacrificing power and speed for maneuverability.
- The bot is now decagon shaped. Soon 100% of decagon robots will have won championships too watch out JVN
- The wheels are still decagons. no one worry

Parts are about to be sent out for metal bending this next Monday. (yes, we told our sponsor that it would be too excessive to use their mill)

In addition, our prototype mini-bot is driving up the pole on average in 2.2 seconds and our prototype roller-gripper quickly grabs all three types of tubes. The lift is still being designed, but I'm happy with where we are. We also are prototyping a "secret weapon" to supplement these necessary mechanisms for the game. It might give us the leading edge It seems like a good rookie season so far. I'll friend you, andrew y, on facebook and we can get together to discuss designs sometime.

23-01-2011 19:19

ProgramLuke

Re: pic: Final 2011 Drivetrain

I would be extremely hesitant to attempt a crab/swerve drive as a rookie team (or even a veteran team!!!) if you haven't done some sort of offseason project to learn how to build one. I would suggest sticking with the 6wd that comes in the KOP so that you can devote more time to your manipulator.

23-01-2011 19:32

BJC

Re: pic: Final 2011 Drivetrain

Who exactly is your sponsor?

23-01-2011 19:32

SudoSammich

Re: pic: Final 2011 Drivetrain

I'd have to agree with luke on this one, swerve drive seems a bit ambitious for a rookie team, especially a rookie team with only four weeks of the build left. 5 axis CNC aside, you still need to be able to accurately assemble, program and learn to drive one of, if not the most, complicated drive system usually attempted in FRC.

It's possible, I suppose, but at that point I'd imagine the professional mentors you have would be doing more of the work than the students, as a rookie team's students generally wouldn't be able to accomplish such a feat. While I've seen rookie teams compete at the top levels of our regional in the past, it was due to the simpler, more solid mechanisms that worked well together and a good driver. Additionally, by the sound of it you haven't really started to BUILD your robot if you're still working on CAD sketches at this point, and that's no small undertaking. Best of luck if you try to pull it off, but I'd be very cautious to first look at a crab system two weeks into the season.

P.S. 2.2 seconds on the minibot? I remember seeing that a 5 lb minibot utilizing ALL the power from a tetrix motor (i.e. no loss in the system, which is just a wee bit impossible) would climb in 6.5 or so. Conservative estimates from that landed a competitive minibot at 7 seconds. It's entirely possible I'm not remembering the thread correctly, but 2.2 still seems a bit extreme.

23-01-2011 19:42

Chris is me

Re: pic: Final 2011 Drivetrain

On the off chance that you guys still aren't trolling, you guys still have quite massive delusions of grandeur - a two speed decagonal swerve drive is ridiculous, especially if you haven't started building or control yet, and especially if you're a rookie team.

Also, trolling CD is a terrible way to get your team attention - mostly because it's the bad kind of attention.

23-01-2011 19:49

kenavt

Re: pic: Final 2011 Drivetrain

For reference on team 3815:

https://my.usfirst.org/myarea/index....ils&tpid=52979.

Their (only) sponsor is "Automation Direct": http://nfrobotics.byethost2.com/?page_id=75

Website: http://raiderrobotics.co.cc/.

Frankly, from their sponsor, I doubt if they have the resources to pull something on this scale off. If anyone could.

23-01-2011 20:10

Creator Mat

Re: pic: Final 2011 Drivetrain

Where would one get a block of aluminum that big? We are sponsored by caterpillar and are able to order material through their tool room, and off hand I'm pretty sure we couldn't get our hands on a block that big (regardless of price).

On another note even if this isn't a troll post (i'm pretty convinced it is however), it is a fun thought experiment on way out their ideas. Plus I wouldn't be surprised if a veteran team or two experiments this off season with a non circular wheel just to see what happens.

23-01-2011 22:16

quinxorin

Re: pic: Final 2011 Drivetrain

Responding to the previous few posts, here's the actual calculations:

CIM starting stall torque (the maximum amount of torque it can exert before stalling and not moving):

343.4 ounce-inches.

Converting to foot-lbs:
(343.4/16)/12 = 1.778 ft-lbs.

Force exerted by each wheel (assuming the wheel is 8in), therefore, is:
1.778 x 3 (4in, the radius, is 1/3 of 12in) = 5.366 lbs-force.

Apparently, each wheel exerts 5.366 lbs of force pushing forward.

Now, let's look at the friction properties of the wheels. Because the wheels are perpendicular, they will have to overcome each other's friction in order to move. At least 2 of the wheels will have to slide at all times.

We can assume that high-traction treads have a coefficient of friction (μ) of at least 1 on carpet, though it is probably much greater (think 1.7-2). I will use 1 as the estimate. An object (i.e. the wheel) is capable of sliding if the following inequality is true: F(force) x μ > weight. The robot, including batteries, bumpers, and the minibot, will weigh 169.2 lbs. Therefore:

5.366 x 2 (there's two wheels) x 1 > 169.2
10.731 >169.2

That inequality is definitely false. Therefore, your robot will not move. Sorry, but it's the sad truth. And that doesn't even include the actual force it would take to move the robot, just to beat the friction of your other wheels.

A lot of people have been posting like me, that the drive train simply won't work. But none have posted a recommendation. If you want traction and not speed, here's mine:

build a six-wheel drive train, wide type. Use traction wheels on one pair of opposing corners and omnis on the other (otherwise your robot won't turn well). Use a gearbox with a ratio of at least 12.75:1 (standard AndyMark Toughbox). If you REALLY, REALLY want traction, put belts on it. I don't recommend that, though.

Here's the lesson to learn from this: You can have traction or you can have speed. You can't have both.

23-01-2011 22:54

LLogan

Re: pic: Final 2011 Drivetrain

I would just like to mention that I believe this team branched off from team 1746.

Team 1746 is the "Forsyth Alliance." It unifies a handful of high schools from a district. It looks like North Forsyth split into their own team, probably consisting of many members that used to be on 1746.

While they may be a new team, they probably aren't "rookies."

I thought the troll was hilarious, anyway.

24-01-2011 00:13

Grim Tuesday

Re: pic: Final 2011 Drivetrain

Ive always assumed that they were extruded that way...

24-01-2011 00:34

Hawiian Cadder

Re: pic: Final 2011 Drivetrain

i always thought they were a strip and had a well hidden seam somewhere.

24-01-2011 01:05

ratdude747

Re: pic: Final 2011 Drivetrain

you have no idea what you are getting into. my current team tried crab thier rookie year. that was all they were able to do. NO manipulator. NO driver practice. NOTHING but a drivetrain. and they started on day two. you are starting two weeks into build season. you have little to no chance of getting it right.

design and build a manipulator and mount it to the kit drivetrain. you need to get it in your head that polygon wheels are hard to make and even harder to use. cavemen invented the wheel. not the decagon. there is a reason.

not to mention oddball frame shapes are only for those who have a lot of human resources and experience.

if you are a troll, leave. go. get a life.

if you are an idiot, quit this nonsense while you are ahead.

if you are unaware, get your head into the game and rethink your work.

sorry to be uber-critical, but i do not tolerate stupidity well.

24-01-2011 10:23

sdcantrell56

Re: pic: Final 2011 Drivetrain

Wow! Way to put down any chance of inspiration for this rookie team. I don't think this is the right way to approach there ideas as out there as they may be. Perhaps you should use all of your asuperior knowledge to help instead of criticize.

24-01-2011 12:31

SudoSammich

Re: pic: Final 2011 Drivetrain

That probably went a bit too far with its choice of language, but I'd agree with the sentiment. Most of the experienced members in this thread are agreeing on one thing at least: attempting a swerve drive with only a month left and a rookie team isn't likely to end well.

A 6WD is solid for this competition, and a simple manipulator combined with a strong drive train will, in my opinion, serve a rookie team better than attempting a drive train they likely won't finish. At the competition there might well be teams who can help them with the last bit of programming and such, but how does that benefit the team?

24-01-2011 12:32

Rion Atkinson

Re: pic: Final 2011 Drivetrain

Soo... This has pretty much all been just repeatedly beating a dead horse since JVN's post. I will say though, I believe this isn't a troll. Though that's because of my past in FIRST. I've dealt with teams that think this would be smart.

So I'll simply say this:

I noticed that your CAD was nice(ish), however, it could use some improving. Here is a few websites that have some nice models for you to use.

FIRST CAD Library

Team 1323's CAD Library

AndyMark

AndyMark doesn't have pure CAD files. But they do have stp files on the gear boxes. Which is helpful because I can't find but two gear boxes. I have to remake the AM Gen 1 Shifter.

Hope that helps. Good luck this season.

Happy Trolling.

24-01-2011 12:34

Chris is me

Re: pic: Final 2011 Drivetrain

If you're two weeks into build and "thought about" doing the OP's drive but then "simplified" down to a two speed swerve drive - you need a reality check, fast.

Brainstorming and creativity are great, but you do actually have to build the ideas you come up with sometime.

24-01-2011 15:31

JesseK

Re: pic: Final 2011 Drivetrain

This thread is full of so much awesome only Andy Baker himself could trump it.

Poohbear, I think we're mocking your pompous attitude rather than your design. As it stands your statements defy physics (and even your followup breaks 1 of Karthik's 2 Golden Rules as Chris pointed out). If this bot worked at you've presented it, then the universe would quite literally rip itself apart from all of the electromagnetic law violations. Thus, we're going to error on the side of caution .... err, at least I will ... because I like my life, and want to live to see May without the world ripping itself apart.

24-01-2011 15:51

Brandon Holley

Re: pic: Final 2011 Drivetrain

Gotta call shenanigans here...

You say it's averaging 2.2 seconds, which means in some cases it's actually going faster than that. Are you adhering to all the minibot requirements? Is the pole you are using for testing regulation size?

In our tests, and from my observations of other teams minibot postings, 2.2 seconds would be far, far, far and away the fastest minibot I've encountered. Considering A. the requirements that everyone must use to build the same minibot and B. the number of teams attempting the same challenge with said requirements, it seems unlikely that someone could build a minibot that is simply THAT far superior than any other.

As they say, pics (or in this case vids) or it didn't happen...

-Brando

24-01-2011 15:52

Cory

Re: pic: Final 2011 Drivetrain

You guys are getting trolled so hard. You honestly think that someone would machine a chassis out of a 800 lb block of what is essentially unobtanium (7071 Al), with ridiculous wheels that would clearly never roll, or then decide when you point out how ridiculous their "design" is that they're going to make a 2 speed swerve instead?

It's clearly sarcasm and this guy is clearly enjoying the heck out of the fun he's having at everyone else's expense.

24-01-2011 15:54

ratdude747

Re: pic: Final 2011 Drivetrain

I see being honest was an incorrect move. i guess i should encourage teams to try stupid ideas... (sarcasm)

i'm sorry, but spoonfeeding false encouragement is in my eyes, not helpful.

I was not mocking, i was pointing out that some basic concepts were being broken. I never said that the OP was stupid, nor did i imply such. unknowing or ignorant, perhaps, but not stupid.

24-01-2011 16:29

BRAVESaj25bd8

Re: pic: Final 2011 Drivetrain

I'm sorry but this seems like a ridiculous design. Some classic rookie mistake IMO.

1. There is limited space for putting sweet magnets on your robot. Switch to steel, the sweet magnets will be abundant.

2. Decagons? Aluminum comes in rectangular blocks, not decagonal blocks. Using squares would save you a lot of fabrication time.

3. None of the wheels come out the side of your robot. Think about this. Your robot has 12 sides (10 veritcal planes plus top and bottom) and you can only drive it if the bottom face stays on the bottom? You clearly have no chance of doing some sweet side-riding.

4. I do not see any wings. If you plan to go that fast, why not put some wings on it and try to catch air for a few seconds?

5. Creativity is minimal here. Come on, you don't think we've all seen the "Holonomic, decagonal wheeled, high traction, 154 fps, solid aluminum block" robot before? This is old hat my friend.

Finally, I would like to say how surprised I am that nobody pointed out these flaws earlier. I'm lucky I did, as I really would hate to see so much time going into a design and then forgetting about sweet magnet space. Good luck this year. Best thread I have read in a while.

24-01-2011 16:33

Justin Montois

Re: pic: Final 2011 Drivetrain

Ya'll are posting in a troll thread.

24-01-2011 16:35

JesseK

Re: pic: Final 2011 Drivetrain

But it's so much FUN!

You have to admit, that comic strip was hilarious.

26-01-2011 11:21

santosh

Re: pic: Final 2011 Drivetrain

I can has trollburger?

26-01-2011 13:08

Doug G

Re: pic: Final 2011 Drivetrain

I can't help myself...

Please PoohBear, I want to hear more. Can you elaborate on your plans for a control system (sensors, programming, etc...) on this beast of a robot your team is putting together?

04-01-2012 22:27

santosh

Re: pic: Final 2011 Drivetrain

I am hoping somebody tries this for 2012. I was sad to see that this design didn't hit the field.

04-01-2012 23:32

VKP

Re: pic: Final 2011 Drivetrain

For our 2012 robot, we've been thinking about a 22-sided chassis with three triangular omni-wheels, because triangles are, of course, the most stable structure. Cims will power the wheels individually, geared for high torque.

This will be our game object manipulator:
http://kottke.org/10/10/robot-beanba...-grip-anything

We will have five of those.

07-01-2012 22:48

Andrew Y.

Re: pic: Final 2011 Drivetrain

AS the build season begins, I think we need to really look back at some of the most innovative designs that were EVER seen in 2011. This is one such. PLEASE. EVERYONE needs to read this whole thread. you will learn a LOT.

7071 FOR THE WIN

08-01-2012 00:37

Joe Schornak

Re: pic: Final 2011 Drivetrain

I think that my design guide posted here still holds some excellent points for building a super-awesome machine!

08-01-2012 11:06

Re: pic: Final 2011 Drivetrain

I think that aluminum frame may be worth over $700-800 market value, which is going to violate <R14>, you'll want to check that.

08-01-2012 11:23

ratdude747

Re: pic: Final 2011 Drivetrain

Not this thread again

15-01-2014 14:15

MaxMax161

Re: pic: Final 2011 Drivetrain

I just found this thread and I would like to say it's completely wonderful.

The only suggestion I would make is since we all know more motors --> better robot you clearly need an 8 motor drive train. However I don't know if there's space for a traditional gearbox, have you thought about mounting extra motors to your motors so they spin while they spin?

17-06-2014 15:52

asid61

Re: pic: Final 2011 Drivetrain

I have to say, this was one of the funniest threads I have ever seen.
6 cims drives are also good too; if the OP is still around I would add that.
There's also 4 minicims available for moar acceleration.

17-06-2014 16:26

XaulZan11

Re: pic: Final 2011 Drivetrain

Maybe he wasn't so crazy after all...

17-06-2014 17:34

Chris is me

Re: pic: Final 2011 Drivetrain

Heh. For those of you that didn't compete in 2011, the fastest minibots of that year were at or just under 1 second from deploy to points. A 2.2 second minibot I would definitely consider "slow" by the end of the year.

17-06-2014 17:37

Andrew Schreiber

Re: pic: Final 2011 Drivetrain

And yet... in the overwhelming majority of matches even a 2.2 second minibot would have won the race.

17-06-2014 17:59

cmrnpizzo14

Re: pic: Final 2011 Drivetrain

*the match

17-06-2014 18:33

BBray_T1296

Re: pic: Final 2011 Drivetrain

The minibot I built climbed the pole in roughly 5 seconds, yet we lost only 1 quali match (in Dallas, our 2nd regional). Every time our bot TOUCHED the pole, it scored*. One match at Alamo, the minibot fell out of our poor holder, was RAN OVER by another robot, and I walked over to it post match, zero damage.



(* except when the battery cable was knocked out and we lost by 1 point in eliminations (grr im still mad))

17-06-2014 18:33

BBray_T1296

Re: pic: Final 2011 Drivetrain

Also, booooooooo to whoever ressurected this thread

11-08-2015 16:35

RoboChair

Re: pic: Final 2011 Drivetrain

Also for reference, this site seems to be redirecting to a porn hosting service currently.

11-08-2015 18:16

MaGiC_PiKaChU

Re: pic: Final 2011 Drivetrain

My reaction when i saw this thread a few years ago

12-08-2015 00:26

BigBen

Re: pic: Final 2011 Drivetrain

12-08-2015 08:08

Taylor

Re: pic: Final 2011 Drivetrain

I blame BigJ.

12-12-2016 14:06

logank013

Re: pic: Final 2011 Drivetrain

Thread Revival Warning: I saw this post in the spotlight quotes. What are Karthik's 2 Golden Rules? Or was that just made up in this post?

12-12-2016 14:08

Cothron Theiss

Re: pic: Final 2011 Drivetrain

Utilizing the search function would answer your question.

12-12-2016 14:12

frcguy

Re: pic: Final 2011 Drivetrain

Karthik's 2 Golden Rules are most definitely a thing. I've quoted them below:

These come from a presentation by Karthik about Effective FIRST Strategies, for which you can find the slide deck here. Highly recommend reading it, it is incredibly informative and pretty awesome.