Go to Post I say we just organize a top-secret raid into FIRST HQ one night. - Steven Donow [more]
Home
Go Back   Chief Delphi > FIRST > General Forum
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 06-01-2014, 17:12
heisenburger heisenburger is offline
Registered User
FRC #4716
 
Join Date: Dec 2013
Rookie Year: 2014
Location: Canada
Posts: 14
heisenburger is an unknown quantity at this point
Mecanum wheels

Hi, I was just wondering what is the purpose of the mecanum wheels, how do they work and are they worth the $400 for the set of 4, also if the sell them somewhere else cheaper than that could you give me the link?
Reply With Quote
  #2   Spotlight this post!  
Unread 06-01-2014, 17:15
cjl2625's Avatar
cjl2625 cjl2625 is offline
apel py
AKA: Cory Lynch
FRC #2067 (Apple Pi)
Team Role: Programmer
 
Join Date: Jan 2013
Rookie Year: 2013
Location: Guilford, CT
Posts: 412
cjl2625 is a splendid one to beholdcjl2625 is a splendid one to beholdcjl2625 is a splendid one to beholdcjl2625 is a splendid one to beholdcjl2625 is a splendid one to beholdcjl2625 is a splendid one to beholdcjl2625 is a splendid one to beholdcjl2625 is a splendid one to behold
Re: Mecanum wheels

Mecanums have some nice maneuverability. They are able to strafe, for example. (you can find some videos of it on YouTube)

However, mecanum wheels will be weak for pushing power and can slide around.
You'll likely be pushed around a lot on the field if you use them
Reply With Quote
  #3   Spotlight this post!  
Unread 06-01-2014, 17:17
atucker4072's Avatar
atucker4072 atucker4072 is offline
Andrew Tucker
AKA: Andrew Tucker
FTC #4968 (Rapid Robotics)
Team Role: Mentor
 
Join Date: Feb 2012
Rookie Year: 2011
Location: Glenwood Springs, Co
Posts: 152
atucker4072 has a spectacular aura aboutatucker4072 has a spectacular aura aboutatucker4072 has a spectacular aura about
Re: Mecanum wheels

Quote:
Originally Posted by heisenburger View Post
Hi, I was just wondering what is the purpose of the mecanum wheels, how do they work and are they worth the $400 for the set of 4, also if the sell them somewhere else cheaper than that could you give me the link?
Where have you looked?

Also make sure you know what size you need. Don't use mecanum wheels just for a cool factor. Mecanum wheels are great for maneuverability, but when it comes to pushing they are worthless.
Reply With Quote
  #4   Spotlight this post!  
Unread 06-01-2014, 17:29
lethc's Avatar
lethc lethc is offline
#gkccurse
AKA: Becker Lethcoe
FRC #1806 (S.W.A.T.)
Team Role: Alumni
 
Join Date: Nov 2012
Rookie Year: 2013
Location: Smithville, MO
Posts: 119
lethc will become famous soon enough
Re: Mecanum wheels

Quote:
Originally Posted by heisenburger View Post
Hi, I was just wondering what is the purpose of the mecanum wheels, how do they work and are they worth the $400 for the set of 4, also if the sell them somewhere else cheaper than that could you give me the link?
My team used mecanums last year and they worked well for sliding into place at the feeder station. However, they were terrible when we tried to cycle and were pushed extremely easily. This year may not be the best for mecanums simply because of the lack of safe zones - you can be pushed at any time with nowhere to retreat.

The choice is completely dependent on your team's strategy. Is your shooter reliant on consistent positioning? If so, you may not want to use mecanums because of the pushing issue.
Reply With Quote
  #5   Spotlight this post!  
Unread 06-01-2014, 18:21
azcalg's Avatar
azcalg azcalg is offline
Registered User
FRC #1212 (Sentinels)
Team Role: Engineer
 
Join Date: Jan 2014
Rookie Year: 2012
Location: Chandler, AZ
Posts: 36
azcalg is a jewel in the roughazcalg is a jewel in the roughazcalg is a jewel in the roughazcalg is a jewel in the rough
Re: Mecanum wheels

In this game the only big advantage I see for them is with catching the ball from the truss, so unless that's a big part of your strategy, I wouldn't get them. Another downside to them is that they're quite heavy.
Reply With Quote
  #6   Spotlight this post!  
Unread 06-01-2014, 18:23
brennanvhoek brennanvhoek is offline
Registered User
AKA: Brennan VandenHoek
FRC #1425 (Error Code Xero)
Team Role: Mechanical
 
Join Date: Mar 2013
Rookie Year: 2009
Location: Newberg, Oregon
Posts: 10
brennanvhoek is on a distinguished road
Re: Mecanum wheels

Mecanum work well if they fit your game strategy. You can get a full set for much less then $400. Vex pro sells a set of 6" for 159.99 http://www.vexrobotics.com/vexpro/wh...um-wheels.html

Also, in my experience the vex wheels preform much better then the andymark equivalent.
Reply With Quote
  #7   Spotlight this post!  
Unread 06-01-2014, 18:29
jbsmithtx's Avatar
jbsmithtx jbsmithtx is offline
FIRST Fanatic
AKA: Josh Smith
FRC #4206 (RoboVikes)
Team Role: Engineer
 
Join Date: Aug 2012
Rookie Year: 2012
Location: Fort Worth, TX
Posts: 91
jbsmithtx is a jewel in the roughjbsmithtx is a jewel in the roughjbsmithtx is a jewel in the rough
Re: Mecanum wheels

Try VEXpro. They have very affordable yet durable mecanum wheels. The other posters are correct in assuming that unless you are trying to catch, mecanums might not work well this year... However don't believe they are easy to push. We had to play defense with our mecanums last year in matches when our shooter failed and were fine. We could block lots of teams. I know this is contrary to popular belief, but a properly done mecanum drive base can in fact be very strong.

For anyone that wants to question our pushing abilites, we have video...
Reply With Quote
  #8   Spotlight this post!  
Unread 06-01-2014, 18:33
Oblarg Oblarg is offline
Registered User
AKA: Eli Barnett
FRC #0449 (The Blair Robot Project)
Team Role: Mentor
 
Join Date: Mar 2009
Rookie Year: 2008
Location: Philadelphia, PA
Posts: 1,116
Oblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond repute
Re: Mecanum wheels

Quote:
Originally Posted by jbsmithtx View Post
Try VEXpro. They have very affordable yet durable mecanum wheels. The other posters are correct in assuming that unless you are trying to catch, mecanums might not work well this year... However don't believe they are easy to push. We had to play defense with our mecanums last year in matches when our shooter failed and were fine. We could block lots of teams. I know this is contrary to popular belief, but a properly done mecanum drive base can in fact be very strong.

For anyone that wants to question our pushing abilites, we have video...
Mecanum wheels, neglecting friction in the rollers, have an effective coefficient of friction that is a factor of sqrt(2)/2 reduced from that of a traction wheel made of the same material. You can verify this yourself by drawing a free-body diagram of a set of mecanum rollers in contact with the ground.

Whether or not this translates to "being pushed all over the field" depends critically on context (robot weight, weight/drive of opposing robot, weight distribution, manner in which you're hit, etc).
__________________
"Mmmmm, chain grease and aluminum shavings..."
"The breakfast of champions!"

Member, FRC Team 449: 2007-2010
Drive Mechanics Lead, FRC Team 449: 2009-2010
Alumnus/Technical Mentor, FRC Team 449: 2010-Present
Lead Technical Mentor, FRC Team 4464: 2012-2015
Technical Mentor, FRC Team 5830: 2015-2016
Reply With Quote
  #9   Spotlight this post!  
Unread 06-01-2014, 18:35
math311's Avatar
math311 math311 is offline
Registered User
FRC #2077 (LaserBots)
Team Role: Leadership
 
Join Date: Sep 2011
Rookie Year: 2010
Location: Wisconsin
Posts: 47
math311 is an unknown quantity at this point
Re: Mecanum wheels

My team has used mecanum wheels for the last three competitions, and each time we had great success with our drivetrain.

The system is meant to give a robot high levels of maneuverability, and when it is allowed to move at high speed, it creates a formidable opponent. Having the range of motion provided by a mecanum drive can allow a driver to jump out of the way of onrushing defenders, all while maintaining a scoring opportunity

When discussing pushing and mecanum, it should not be forgotten that the goal of this drivetrain is maneuverability, not brute strength. Due to this, a pushing match with a robot designed for pushing will be lopsided. But that does not mean that this drivetrain is easy to push. I have seen our past mecanum drives stop six wheel drives dead, and win pushing matches. When we use mecanum, we maintain a balance of speed and pushing power, and ensure we are not compromising one for the other.

This quote sums the entire discussion up, and is good food for thought. "Mecanum drivetrains, like every other, have advantages and disadvantages" - Mr. B
__________________
2008 Wisconsin Regional Judges Award Winner
2010 Wisconsin Regional Delphi "Driving Tomorrows Technology" Award Winner
2013 Wisconsin Regional Quarter Finalist
Reply With Quote
  #10   Spotlight this post!  
Unread 06-01-2014, 21:19
Random42 Random42 is offline
Registered User
FRC #4533
Team Role: Mentor
 
Join Date: Jan 2013
Rookie Year: 2011
Location: Mt. Pleasant SC.
Posts: 5
Random42 is an unknown quantity at this point
Re: Mecanum wheels

I have a quick question about mecanum wheels. Can they be placed in a trapezoidal configuration?

Has anyone tried this before? How well does it work?
Reply With Quote
  #11   Spotlight this post!  
Unread 06-01-2014, 21:32
cmrnpizzo14's Avatar
cmrnpizzo14 cmrnpizzo14 is offline
Registered User
AKA: Cam Pizzo
FRC #3173 (IgKNIGHTers)
Team Role: Mentor
 
Join Date: Jan 2011
Rookie Year: 2006
Location: Boston
Posts: 522
cmrnpizzo14 has a reputation beyond reputecmrnpizzo14 has a reputation beyond reputecmrnpizzo14 has a reputation beyond reputecmrnpizzo14 has a reputation beyond reputecmrnpizzo14 has a reputation beyond reputecmrnpizzo14 has a reputation beyond reputecmrnpizzo14 has a reputation beyond reputecmrnpizzo14 has a reputation beyond reputecmrnpizzo14 has a reputation beyond reputecmrnpizzo14 has a reputation beyond reputecmrnpizzo14 has a reputation beyond repute
Re: Mecanum wheels

Quote:
Originally Posted by Random42 View Post
I have a quick question about mecanum wheels. Can they be placed in a trapezoidal configuration?

Has anyone tried this before? How well does it work?
Could you describe the configuration you are thinking of? Do you mean something like this:

---[]----[]---


[]----------[]

where the [] are wheels and you have the front wheels in narrower (or the back wheels)?
__________________
FIRST Team 3173 The IgKNIGHTers

"Where should we put the battery?"
Reply With Quote
  #12   Spotlight this post!  
Unread 06-01-2014, 21:37
Keegbot's Avatar
Keegbot Keegbot is offline
Registered User
AKA: Keegan McCrary
FRC #2438 (Beta Blues)
Team Role: College Student
 
Join Date: Jan 2014
Rookie Year: 2012
Location: Honolulu, Hawaii
Posts: 40
Keegbot is an unknown quantity at this point
Re: Mecanum wheels

Quote:
Originally Posted by jbsmithtx View Post
Try VEXpro. They have very affordable yet durable mecanum wheels. The other posters are correct in assuming that unless you are trying to catch, mecanums might not work well this year... However don't believe they are easy to push. We had to play defense with our mecanums last year in matches when our shooter failed and were fine. We could block lots of teams. I know this is contrary to popular belief, but a properly done mecanum drive base can in fact be very strong.

For anyone that wants to question our pushing abilites, we have video...
Our team used the VEXpro wheels last year, and I was very pleased with them. They lasted 2 competitions and multiple fundraisers until they started to fall apart. They are also quiet and light compared to the Andy Mark versions we have used in the past. We also had to be purely defensive in one competition and managed to place high because our mecanum drive allowed us to out-maneuver our opponents and get in front of them to block their shots.
Reply With Quote
  #13   Spotlight this post!  
Unread 06-01-2014, 22:03
Caleb Sykes's Avatar
Caleb Sykes Caleb Sykes is offline
Registered User
FRC #4536 (MinuteBots)
Team Role: Mentor
 
Join Date: Feb 2011
Rookie Year: 2009
Location: St. Paul, Minnesota
Posts: 1,074
Caleb Sykes has a reputation beyond reputeCaleb Sykes has a reputation beyond reputeCaleb Sykes has a reputation beyond reputeCaleb Sykes has a reputation beyond reputeCaleb Sykes has a reputation beyond reputeCaleb Sykes has a reputation beyond reputeCaleb Sykes has a reputation beyond reputeCaleb Sykes has a reputation beyond reputeCaleb Sykes has a reputation beyond reputeCaleb Sykes has a reputation beyond reputeCaleb Sykes has a reputation beyond repute
Re: Mecanum wheels

I encourage anyone and everyone who thinks that they understand mecanum physics to read the whitepaper given here: http://www.chiefdelphi.com/media/papers/2759?
Reply With Quote
  #14   Spotlight this post!  
Unread 06-01-2014, 23:01
Random42 Random42 is offline
Registered User
FRC #4533
Team Role: Mentor
 
Join Date: Jan 2013
Rookie Year: 2011
Location: Mt. Pleasant SC.
Posts: 5
Random42 is an unknown quantity at this point
Re: Mecanum wheels

Quote:
Originally Posted by cmrnpizzo14 View Post
Could you describe the configuration you are thinking of? Do you mean something like this:

---[]----[]---


[]----------[]

where the [] are wheels and you have the front wheels in narrower (or the back wheels)?
Yes. Something very similar to this. The back wheels would be about 12in apart and the front about 24in apart. The front and back wheels would be about 30in apart.
Reply With Quote
  #15   Spotlight this post!  
Unread 06-01-2014, 23:01
BEN35678's Avatar
BEN35678 BEN35678 is offline
Mentor
FRC #1523 (MARS)
Team Role: Mechanical
 
Join Date: Oct 2013
Rookie Year: 2012
Location: Jupiter, Florida
Posts: 41
BEN35678 is an unknown quantity at this point
Re: Mecanum wheels

Quote:
Originally Posted by Keegbot View Post
Our team used the VEXpro wheels last year, and I was very pleased with them. They lasted 2 competitions and multiple fundraisers until they started to fall apart. They are also quiet and light compared to the Andy Mark versions we have used in the past. We also had to be purely defensive in one competition and managed to place high because our mecanum drive allowed us to out-maneuver our opponents and get in front of them to block their shots.
Last year we used Andymark mecanum and this year we were looking at the vex pro mecanums, and a couple of our main mentors were worried about them cracking because they are plastic. Did you have anything that looked like it was about to crack or anything like that?
Reply With Quote
Reply


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


All times are GMT -5. The time now is 06:25.

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


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi