Mechanum Wheels?
 

I've been observing CD for a few days and noticed that amongst all the discussions of drive trains, there has been nothing major said about mechanum wheels. One or two threads mentioned them in passing, but I was curious, as my team decided to go with mechanums, why others were choosing to not go this direction?

Re: Mechanum Wheels?
 

We are using mechanum wheels this year, for a few reasons. One we love them. Two the provide great maneuverability. Three there big enough to get over the bump. I really like them.

Re: Mechanum Wheels?
 

What size are you using? getting over the bump was something my team thought to be impossible, but our wheels might be a smaller size. do you think you will have any trouble with traction on the bridge?

Re: Mechanum Wheels?
 

Here is FIRST team 2849 ursamajor and thier sucess with meccaums they workk in bump and terrific on the bridge .We used 8in wheel i am a veteran and mentor on the team.Bumps coming sooon
http://www.youtube.com/watch?v=3Hju0...y7UjRNgBKiTb8I

Re: Mechanum Wheels?
 

Have you actually tested this?

Re: Mechanum Wheels?
 

Pics or it didn't happen



Mecanum = chucknorris of wheels(does chuck Norris weigh more than120? :).

Re: Mechanum Wheels?
 

We are using the 8 inch. The rollers are incredibly grippy on the bridge, I fore see no issues. More testing will likely occur tomorrow. I will post any thing else we find out about them on here tomorrow. Why would they have a problem with the bump?

Re: Mechanum Wheels?
 

The decision to use mecanum wheels is a strategy-based one... if you plan to play a heavy, pushing defense, mecanum is probably the wrong choice, as the diagonal wheels are not so great at traction. If you plan to play a swift and extremely maneuverable offense, then mecanum may be the choice for you. Mecanum wheels are also larger than many plain plaction wheels, which may assist you when climbing the bump. The size can also push your CG up, depending on where you fasten the wheel centers.

Re: Mechanum Wheels?
 

Sorry forgot to add the video

Re: Mechanum Wheels?
 

8" wheels, 4" bump, your axle hits smack-dab on the top of the bump. That makes it a little bit tricky to get up and over; I'd put a set of skid plates to knock the bump under the axle to help the robot get over the barrier.

Re: Mechanum Wheels?
 

I dont get it. As long as your not going mock 5, ok ok at fast speed in terms of robotics competitions, the back wheels will continue to push as you some what gently push your self over the bump. But we will test this tomorrow.

Re: Mechanum Wheels?
 

I'm not saying no mecanums (or however you spell it), but these are some points made in previous threads:

-Less traction on the key
-As already said, loss in pushing power
-Heavy
-Forces you to use maximum number of motors for drivetrain (not usually an issue)
-While they may not affect your ability to go on the bridge, the ability to stay without being pushed off or falling off of the bridge tips your direction will be tough to deal with
-You won't be driving circles around other's bots unless you have a lot of practice.
-In order to work to their fullest extent, require a lot of thorough engineering
-More complicated to code, even at the minimum level


Like I said, I'm not telling you not to use them, but when you do, be careful and engineer it through (Not meant to sound like most interesting man in the world meme, though I'm tempted. ;))

Re: Mechanum Wheels?
 

I disagree with this statement. WPI has a complete library for mecanum wheels. My old team used them last year for the first time and had them programmed on the drivetrain the day we received the shipment from AndyMark.

Re: Mechanum Wheels?
 

I mean when you go into the real nitty gritty coding stuff. THe code they give you is fine, but to make it better takes some work.

This is just what I've been told by our programmers, I'm not a master of code myself, however my trustful programmers are.

Re: Mechanum Wheels?
 

• We've been using Mecanums for the past three years and have found no huge loss of traction
• Usually, but this depends on the drivetrain.
• Definitely; Mecanums are a lot heavier than conventional wheels.
• I think most teams use 4 CIMs to drive anyway because it gives the robot a ton of power.
• Mecanums powered by Toughboxes don't get pushed around as much as people think, but it's defeinitely soemthing to consider.
• Agreed, a lot of practice is needed with Mecanums to be extremely good at them.
• Not a lot of engineering, it's really only the initial one-time assembly that matters in the long run.
• Actually, my team uses all of 20 characters for our Mecanum code, not counting the button to turn it on ;)

Just my experiences with Mecanums.