22-05-2006 21:51

Simon Strauss

Re: pic: AndyMark Mecanums

Its Beautiful, nothing more to say.

22-05-2006 21:53

Rohith Surampudi

Re: pic: AndyMark Mecanums

::jaw drops::

how much do these run for?

22-05-2006 21:58

Ryan Foley

Re: pic: AndyMark Mecanums

See this thread for more discussion on these wheels.

Or, go directly to Andy Baker's post

22-05-2006 22:09

sanddrag

Re: pic: AndyMark Mecanums

Wow, impressive. I can't picture how all those tabs would be precisely bent. Looks kind of like looking inside a jet engine.

22-05-2006 22:11

Kyle Love

Re: pic: AndyMark Mecanums

There is a beast of a "mold" (I do not know the technical term for it) used to bend the tabs the same each time. I love these wheels, they are great to just have fun with and could be valuable in future games where maneuverability is key.

22-05-2006 22:16

Joe_Widen

Re: pic: AndyMark Mecanums

I'm pretty sure AndyMark uses a press. It would be the easiest and most efficient way to produce 1000+ wheels.

22-05-2006 22:31

Jonathan Norris

Re: pic: AndyMark Mecanums

So where can I buy some .

22-05-2006 22:35

Rohith Surampudi

Re: pic: AndyMark Mecanums

they arent on the website yet, but here

Huzah for AndyMark

23-05-2006 10:12

bigboi146

Re: pic: AndyMark Mecanums

I dont get them. Can you use them in an omni drive. they look awsome though.

23-05-2006 11:06

Qbranch

Re: pic: AndyMark Mecanums

OK here's something that has bugged me for years.

can someone verify that:

1. The wheels for holonomic drive are called "Mecanum" wheels.
2. The drive system itself is called "holonomic drive"
3. The drive system is not called "Mecanum drive"

PM me or just reply here. Thanks.

-Q

23-05-2006 11:14

Richard Wallace

Re: pic: AndyMark Mecanums

My understanding is that 'holonomic' means 'able to translate and rotate simultaneously'. Holonomic drive can be implemented using mecanum wheels or omniwheels.

23-05-2006 11:15

ahecht

Re: pic: AndyMark Mecanums

These look like a promising start if the price makes them affordable enough. However, in their current incarnation I do see a few problems. First, unless you want to thumpthumpthump down the field, I hope the final rollers are a bit rounder than that. Also, these wheels are going to take incredible side loads, so I hope those plates are steel (I would assume so, since these guys seem to know what they are doing).

23-05-2006 11:32

sanddrag

Re: pic: AndyMark Mecanums

I wouldn't be surpised if the production wheels remain relatively unchanged. I have a feeling those plates are quite strong due to the manner in which those tabs are bent. And for the rollers, I have a feeling those edges may have some traction enhancing properties. Just guesses though.

23-05-2006 12:05

Billfred

Re: pic: AndyMark Mecanums

I saw them in Atlanta, and they felt pretty solid to me (at least for prototypes). I've seen a lot of things made from 1/8" aluminum, and it seems to hold up to plenty of abuse, especially once you start putting some bends in there. They were a bit heavier than, say, IFI wheels might be, but welcome to the world of mecanum wheels.

As I have yet to work with mecanum drive, I'd have to leave judgment on the rollers to The People That Know What They Are Doing(tm).

23-05-2006 13:19

Qbranch

Re: pic: AndyMark Mecanums

Have you all seen the vehicles that AIRTRAX is making holonomic?

I was amazed that they figured out how to do holonomic drive for forklifts and scissor lifts.

Just something that caught my interest.

-Q

23-05-2006 14:45

Alan Anderson

Re: pic: AndyMark Mecanums

With enough weight on the wheels, the TechnoKats' prototype mecanum drive base is very smooth. The installed rollers are sufficiently "squishy" that they don't do a lot of thumping to begin with, and they also wore down a bit to a slightly rounder profile after driving on concrete for a while.

23-05-2006 16:42

artdutra04

Re: pic: AndyMark Mecanums

See these pictures for examples of holonomic and mecanum drive robots.

23-05-2006 17:55

Richard Wallace

Re: pic: AndyMark Mecanums

Wikipedia actually has a pretty good definition of holonomic as the term applies to robots:

So a robot drivetrain that is truly holonomic as defined above would have three degrees of freedom; i.e., three independently controllable wheels not directed along the same axis. A robot drivetrain with four omniwheels arranged on the corners is actually redundant, but with relatively simple math can be made to function like one that is holonomic. The same statement applies to a robot drivetrain with four mecanum wheels.

23-05-2006 18:17

Simon Strauss

Re: pic: AndyMark Mecanums

Aka Kiwi drive which is usually categorized with the Holonomic drive Art had above due to their usage of the same type of wheel

23-05-2006 18:52

EricH

Re: pic: AndyMark Mecanums

See the explanations above. A "mecanum" drivetrain is set up like a four wheel drive with each wheel independently powered. You cannot have two wheels powered by the same motor/tranny. If you do, you will lose all sideways ability, and you may as well go with four wheel drive. There are three teams that I know about that have used this setup in competition. Note: If you tried to use them in a "standard" omni drive (Art's left-hand pic), you would go nowhere, or possibly spin out or fry a motor or something else equally bad. (Actually, mecanum drive is a subset of omni drive.)

23-05-2006 19:22

RogerR

Re: pic: AndyMark Mecanums

actually, in a four wheel omni-drive, if you paired the wheels across from each other together and attached them to a motor, you'd be able to translate freely. unfortunately, this'd mean you would be unable to rotate. i believe you could achieve similar results by pairing the the diagonal wheels on a mecanum drive train together.

23-05-2006 19:41

EricH

Re: pic: AndyMark Mecanums

Now that I think about it, yes you could, in theory. Again, you could not turn the robot. Also, it might be a bit difficult to link a wheel on the left front corner with the one on the right back corner...

23-05-2006 19:45

Simon Strauss

Re: pic: AndyMark Mecanums

there are ways, such as elaborate rotating shafts or using tapered gears to angle them the needed degrees then run those together with chain and sprocket with a motor and tranny in the center, would be heavy though.

23-05-2006 22:36

ahecht

Re: pic: AndyMark Mecanums

When 190 made our mecanum wheel, we originally had our rollers supported by 1/8" aluminum tabs, but we found that lose quickly bent when supporting a 130 pound robot making rapid movements. We switched to 1/8" steel, and while those were much better, we still had the occasional bent tab.

24-05-2006 16:50

EricH

Re: pic: AndyMark Mecanums

And mecanums are heavy enough as it is. We can make some pretty light ones if we want to, but they still weigh at least as much as our six-wheel drive. (if you include trannies on both systems)

18-08-2006 16:13

Madison

Re: pic: AndyMark Mecanums

Hey Andy,

Is there any chance you could share some general dimensions for these wheels so that those of us who're considering ordering a set can start to work them into our plans? Unless I've missed it elsewhere, it'd be fantastic to know as little as overall diameter and thickness, but if you've got more than that, I'll take it.

17-09-2006 22:54

WernerNYK

Re: pic: AndyMark Mecanums

1. Mecanum refers to the name of the compnay which the original creator worked for at the time of his invention (or at least to the person whose name is on the patent of the design which is most commonly mimiced by FIRST teams). Bengt Ilon developed this design, if my memory serves me correctly in the mid-1970s.

2. A holonomic platform, most literally is defined as one which has the ability to instantaneously move in any given direction (on a given plane). It does not need to be accomplished with mecanum wheels, and may not necessarily require wheels at all (I'm thinking "bumper boats" right off the top of my head - although not as controllable, these do fit the general terms).

3. There is technically no such thing as a Mecanum drive, although within the FIRST community, a holonomic drive platform using Mecanum-style wheels has become known as a Mecanum drive platform.

I realize this is a few months down the line, but hope it clarifies some things for you -- sorry in advance if any of my "facts" or a bit off, I'm replying to this based solely on memory of research I did almost two years ago.


EDIT: His name was not Ilon Mecanum -- Mecanum was the company he worked for. Ooops.

17-09-2006 23:18

Dan Petrovic

Re: pic: AndyMark Mecanums

The guy who invented Mecanum wheels was Bengt Ilon. I have no idea how they got the name Mecanum. They can be also called Ilon wheels.

This is all according to Wikipedia... and as we all know "I SAW IT ON THE INTERNET IT MUST BE TRUE!"

17-09-2006 23:25

WernerNYK

Re: pic: AndyMark Mecanums

Ah yes, now I remember. You're right.. I retract my prior statement, and say that the company he worked for was "Mecanum something or other"