Go to Post Everyone builds their robots uniquely, runs their teams differently, and prefers all kinds of flavors of ice cream. Now, we are seeing that folks vent and react differently to a frustrating situation. ... and that's ok. - Andy Baker [more]
Home
Go Back   Chief Delphi > Technical > Technical Discussion
CD-Events   CD-Media   CD-Spy   FRC-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 04-03-2006, 03:39 AM
Tatsu Tatsu is offline
Audiophile and Physicist.
AKA: Tatsu Hashimoto
FRC #1072 (Harker Robotics Team)
Team Role: Leadership
 
Join Date: Jan 2006
Rookie Year: 2004
Location: Woodside
Posts: 49
Tatsu will become famous soon enough
Send a message via AIM to Tatsu
Pic: Easy to make mecanums..

Okay, as an offseason project, part of 1072 is making a mecanum drive.
first part (and probably the hardest) is the wheel.

here's our scheme for making one.. we'll make at least one over this break (its spring break for us) and report back how it is.. but if you see any glaring problems, please post asap.

Tools -
A Mill (Bridgeport in our case)
1/4 in end mill / drill bit
1 in , 3/4 shank end mill
Clamp set
Indicator
Vise
Edge finder

Materials -
3/4 plate 6 in x 36 in
Lab-stops (Mcmaster - 9545K15)
Generic 2 3/4, 1/4-20 bolts
1/4-20 nuts
retaining rings.

First, Take the plate, cut into 6 plates of 6 in x 6 in.
Next, bring to our friendly machinist, and have him turn the plate into the following pattern..
http://i27.photobucket.com/albums/c1...3456/Part1.png


Now, take back to the brigeport, tilt the head 45 degrees, and true the vise.
Then after we have that, we can just vise the plate using the octagon.. that will ensure true-ness on one plane (ie the y is now true) and then find the center of the octagon, and then use a 1 in endmill, then a 1/4 in end mill through to get..
http://i27.photobucket.com/albums/c1...3456/Part2.png

Then, since this form is quite awkward, after tramming the head to 90, we make some ornamental cuts.
http://i27.photobucket.com/albums/c1...3456/part3.png

Now there's the hub, the rollers should be equally easy. originally, we were planning on begging for someone with cnc lathe to cut us this profile..
http://i27.photobucket.com/albums/c1...3456/Part4.png

But, our student mentor realized that a lab stop, bored with a .25 in hole would be nearly identical in terms of circularity (the one and maybe even only key measure of wheel performance)
here's comparison of theoretical optical versus lab stops
http://i27.photobucket.com/albums/c1...3456/Part5.png

Finally, it should look like..
http://i27.photobucket.com/albums/c1...3456/Final.png

So. Any suggestions, comments, concerns?

Last edited by Tatsu : 04-03-2006 at 03:42 AM.
  #2   Spotlight this post!  
Unread 04-03-2006, 11:17 AM
sanddrag sanddrag is offline
back to school ;-)
FRC #0696 (Circuit Breakers)
Team Role: Teacher
 
Join Date: Jul 2002
Rookie Year: 2002
Location: Glendale, CA
Posts: 7,745
sanddrag has a reputation beyond reputesanddrag has a reputation beyond reputesanddrag has a reputation beyond reputesanddrag has a reputation beyond reputesanddrag has a reputation beyond reputesanddrag has a reputation beyond reputesanddrag has a reputation beyond reputesanddrag has a reputation beyond reputesanddrag has a reputation beyond reputesanddrag has a reputation beyond reputesanddrag has a reputation beyond repute
Re: Pic: Easy to make mecanums..

Looks like a plan. It's clear you've thought quite a bit about it. Good luck with making it. I'd like to see the finished product!
__________________
Teacher/Engineer/Machinist - Team 696 Circuit Breakers, 2011 - Present
Mentor/Engineer/Machinist, Team 968 RAWC, 2007-2010
Technical Mentor, Team 696 Circuit Breakers, 2005-2007
Student Mechanical Leader and Driver, Team 696 Circuit Breakers, 2002-2004

Support Team 696 on DonorsChoose!
  #3   Spotlight this post!  
Unread 04-04-2006, 07:22 PM
Bill_Hancoc's Avatar
Bill_Hancoc Bill_Hancoc is offline
Volkswagen Enthusiast
AKA: Bill Hancock
FRC #0573 (MechWarriors)
Team Role: Mechanical
 
Join Date: Mar 2005
Rookie Year: 2005
Location: Ortonville MI.
Posts: 589
Bill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud of
Send a message via AIM to Bill_Hancoc
Re: Pic: Easy to make mecanums..

So i thought about this for a lil while and thought of something. My expeirence with lab stop it that it was a very soft compound rubber that seemed to peel and cut very easily. I think i wouldnt be durable enough for driving around on carpet and pushing other bots around.
__________________

MechWarriors 573

  #4   Spotlight this post!  
Unread 04-04-2006, 07:28 PM
Andrew Blair's Avatar
Andrew Blair Andrew Blair is offline
SAE Formula is FIRST with Gasoline.
FRC #0306 (CRT)
Team Role: Alumni
 
Join Date: Feb 2005
Rookie Year: 2004
Location: Corry
Posts: 1,193
Andrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond reputeAndrew Blair has a reputation beyond repute
Send a message via AIM to Andrew Blair Send a message via Yahoo to Andrew Blair
Re: Pic: Easy to make mecanums..

Looks good, but how I hate to see all that Al burned through! Seems pretty possible with no CNC stuff. Though a rotary indexer is a must.
__________________
Reading makes a full man, conference a ready man, and writing an exact man.
-Sir Francis Bacon

"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction."
-Albert Einstein
  #5   Spotlight this post!  
Unread 04-04-2006, 07:34 PM
Madison's Avatar
Madison Madison is offline
Dancing through life...
FRC #0488 (Xbot)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1999
Location: Seattle, WA/Holbrook, NY
Posts: 5,014
Madison has a reputation beyond reputeMadison has a reputation beyond reputeMadison has a reputation beyond reputeMadison has a reputation beyond reputeMadison has a reputation beyond reputeMadison has a reputation beyond reputeMadison has a reputation beyond reputeMadison has a reputation beyond reputeMadison has a reputation beyond reputeMadison has a reputation beyond reputeMadison has a reputation beyond repute
Send a message via AIM to Madison
Re: Pic: Easy to make mecanums..

It's interesting to read others' ideas for producing these sorts of wheels with minimal headaches. I, too, have been giving it some thought lately as a potential off-season project for our team and was trying to design a wheel that could be made using what we have available -- a 3 axis CNC mill, drill press and lathe.

Forgive my lack of step-by-step illustrations
__________________
--Madison--

...down at the Ozdust!

Like a grand and miraculous spaceship, our planet has sailed through the universe of time. And for a brief moment, we have been among its many passengers.
  #6   Spotlight this post!  
Unread 04-04-2006, 08:29 PM
Bill_Hancoc's Avatar
Bill_Hancoc Bill_Hancoc is offline
Volkswagen Enthusiast
AKA: Bill Hancock
FRC #0573 (MechWarriors)
Team Role: Mechanical
 
Join Date: Mar 2005
Rookie Year: 2005
Location: Ortonville MI.
Posts: 589
Bill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud ofBill_Hancoc has much to be proud of
Send a message via AIM to Bill_Hancoc
Re: Pic: Easy to make mecanums..

Ok o searched this one and i couldnt find anything difinative. What is the difference between omni wheels and mercanum wheels. i know the power used i different depending on the direction moving but i thought i read somewhere the it is hard to push bots with mercanum wheels but easy with omni wheels.

any help i appreciated thanks

Bill
__________________

MechWarriors 573

  #7   Spotlight this post!  
Unread 04-04-2006, 11:08 PM
EricH's Avatar
EricH EricH is offline
New year, new team
FRC #1197 (Torbots)
Team Role: Engineer
 
Join Date: Jan 2005
Rookie Year: 2003
Location: SoCal
Posts: 15,254
EricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond repute
Send a message via Skype™ to EricH
Re: Pic: Easy to make mecanums..

Quote:
Originally Posted by Bill_Hancoc
What is the difference between omni wheels and mercanum wheels. i know the power used i different depending on the direction moving but i thought i read somewhere the it is hard to push bots with mercanum wheels but easy with omni wheels.
The difference is the angle of the outer rollers. Omni wheels have their rollers round sides facing at 90 degrees to the wheel's roundness. Mecanums have their rollers at about 45 degrees (though this is variable). If a team has mecanums, you will have a harder time pushing them (due to the angled rollers and the power--four motors available versus two at any given time for omni's). However, it is still possible to push mecanums around, it's just a little harder.
__________________
Past teams:
2003-2007: FRC0330 BeachBots
2008: FRC1135 Shmoebotics
2012: FRC4046 Schroedinger's Dragons

Read the rules and make a picklist before thinking about winning a competition.
  #8   Spotlight this post!  
Unread 04-05-2006, 01:47 AM
MikeJ675's Avatar
MikeJ675 MikeJ675 is offline
Near Chaos Robotics
AKA: Mike Jeffries
no team (Near Chaos Robotics)
Team Role: Engineer
 
Join Date: Jan 2005
Rookie Year: 2004
Location: Norcross, GA
Posts: 109
MikeJ675 is a name known to allMikeJ675 is a name known to allMikeJ675 is a name known to allMikeJ675 is a name known to allMikeJ675 is a name known to allMikeJ675 is a name known to all
Send a message via AIM to MikeJ675
Re: Pic: Easy to make mecanums..

Two quick comments on the first design-

With the support for the rollers in the center, they may not turn as efficiently.(not too big of an issue)

Having the rollers positioned like that will make it easier to bend the supports(leverage and all that) if they get hit. Protect them well.
__________________
Team 675-Alumni

Near Chaos Robotics
  #9   Spotlight this post!  
Unread 04-06-2006, 01:07 AM
Veselin Kolev's Avatar
Veselin Kolev Veselin Kolev is offline
X51 Production Company PGM (TM)
no team
Team Role: Engineer
 
Join Date: Jun 2003
Rookie Year: 2002
Location: CA
Posts: 253
Veselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond repute
Re: Pic: Easy to make mecanums..

Horay for lab stops and ghetto-ness. Hey, if it works, we'll let you guys know. If it doesnt, we'll make it work, and let you know
__________________
X51 Production Company
  #10   Spotlight this post!  
Unread 04-07-2006, 08:56 AM
mechanicalbrain's Avatar
mechanicalbrain mechanicalbrain is offline
The red haired Dremel gnome!
FRC #0623 (Ohm robotics)
Team Role: Electrical
 
Join Date: Apr 2005
Rookie Year: 2004
Location: Virginia
Posts: 1,221
mechanicalbrain has a reputation beyond reputemechanicalbrain has a reputation beyond reputemechanicalbrain has a reputation beyond reputemechanicalbrain has a reputation beyond reputemechanicalbrain has a reputation beyond reputemechanicalbrain has a reputation beyond reputemechanicalbrain has a reputation beyond reputemechanicalbrain has a reputation beyond reputemechanicalbrain has a reputation beyond reputemechanicalbrain has a reputation beyond reputemechanicalbrain has a reputation beyond repute
Send a message via AIM to mechanicalbrain Send a message via Yahoo to mechanicalbrain
Re: Pic: Easy to make mecanums..

I almost wonder if the design by NeilR (http://www.chiefdelphi.com/forums/sh...t=mecanum+sell half way down) wouldn't be easier to make.
http://www.chiefdelphi.com/forums/at...achmentid=3745
__________________
"Oh my God! There's an axe in my head."
623's 2006 home page
random mechanicalbrain slogans

  #11   Spotlight this post!  
Unread 04-07-2006, 11:59 AM
Tytus Gerrish's Avatar
Tytus Gerrish Tytus Gerrish is offline
IGAB, ADHD, and Dislexic
AKA: Ty
FRC #0179 (SwampThing)
Team Role: Tactician
 
Join Date: Feb 2003
Rookie Year: 2001
Location: West Palm Beach, Florida
Posts: 2,005
Tytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond repute
Send a message via Skype™ to Tytus Gerrish
Re: Pic: Easy to make mecanums..

I cant see your pictures while im here at work but from your description your manufacture method is very similar to the latest i've come up with. the term "easy to make" has to be viewed very realitively. because as far as the basic wheel goes there's no real easy wayt to make it without the right tools.
  #12   Spotlight this post!  
Unread 04-09-2006, 04:18 PM
Tatsu Tatsu is offline
Audiophile and Physicist.
AKA: Tatsu Hashimoto
FRC #1072 (Harker Robotics Team)
Team Role: Leadership
 
Join Date: Jan 2006
Rookie Year: 2004
Location: Woodside
Posts: 49
Tatsu will become famous soon enough
Send a message via AIM to Tatsu
Re: Pic: Easy to make mecanums..

update - Disks are done.. mill is cleaned and ready to go.. now all we have to do is make the jig (for accurate indexing) and start cutting... we should have a prototype soon.

Anyway, this could easily be done with a rotary table and a manual mill (no CNC needed.)
  #13   Spotlight this post!  
Unread 04-19-2006, 10:00 PM
Tatsu Tatsu is offline
Audiophile and Physicist.
AKA: Tatsu Hashimoto
FRC #1072 (Harker Robotics Team)
Team Role: Leadership
 
Join Date: Jan 2006
Rookie Year: 2004
Location: Woodside
Posts: 49
Tatsu will become famous soon enough
Send a message via AIM to Tatsu
Re: Pic: Easy to make mecanums..

Victory!

Went milling today, got the wheels done. Here are some pictures. They still need to be cheeseholed, but meh. we've 7 more to go!
(sorry for low-res, taken on my camerafone)

Blanks
http://i27.photobucket.com/albums/c1...456/Blanks.jpg

Initial setup
http://i27.photobucket.com/albums/c1.../MillSetup.jpg

Closeup of the jig
http://i27.photobucket.com/albums/c1...tupCloseup.jpg

First cut
http://i27.photobucket.com/albums/c1...6/FirstCut.jpg

Second cut
http://i27.photobucket.com/albums/c1.../SecondCut.jpg

Assembled
http://i27.photobucket.com/albums/c1.../Assembled.jpg


(NB - the steel rule is a 6" scale)

We didnt really NEED a mill, we could have done this with a drill press =p. As long as you can get the blanks, you can make these mecanums with a drill press and bandsaw. but a mill is nice =p.

Last edited by Tatsu : 04-19-2006 at 10:03 PM.
  #14   Spotlight this post!  
Unread 04-19-2006, 10:49 PM
Tytus Gerrish's Avatar
Tytus Gerrish Tytus Gerrish is offline
IGAB, ADHD, and Dislexic
AKA: Ty
FRC #0179 (SwampThing)
Team Role: Tactician
 
Join Date: Feb 2003
Rookie Year: 2001
Location: West Palm Beach, Florida
Posts: 2,005
Tytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond reputeTytus Gerrish has a reputation beyond repute
Send a message via Skype™ to Tytus Gerrish
Re: Pic: Easy to make mecanums..

cool. nice to see them done. what machine are these destined to be a part of?
  #15   Spotlight this post!  
Unread 04-19-2006, 11:51 PM
Veselin Kolev's Avatar
Veselin Kolev Veselin Kolev is offline
X51 Production Company PGM (TM)
no team
Team Role: Engineer
 
Join Date: Jun 2003
Rookie Year: 2002
Location: CA
Posts: 253
Veselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond reputeVeselin Kolev has a reputation beyond repute
Re: Pic: Easy to make mecanums..

These wheels are for prototyping. We are going to have two such wheels, and two mirrored (and of course spares) on a robot. They will be run direct driven off four KOP transmissions with encoders on a KOP chassis. This is to perfect the wheel design and code behind mecanum drive. If we deem the drive reliable and useful enough, we might just use this next year.
__________________
X51 Production Company
Closed Thread


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Linux and new microcontollers. djcapelis Programming 48 01-28-2005 11:26 PM
How to pass your inspection at Nationals, the EASY way Matt Reiland Championship Event 0 04-04-2003 05:39 PM
Please help make the Nationals in Houston AWESOME ... You be the Tournament Director Natchez General Forum 42 12-13-2002 05:50 PM
5 points I make..(and a little excess) archiver 1999 7 06-23-2002 09:18 PM
(CURIE) Let's make this Easy for all of us. [scouting] 157#1Driver Championship Event 13 04-22-2002 07:56 AM


All times are GMT -5. The time now is 01:45 AM.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi