2015: Year of the Mecanum

We were warned that “Change is Coming,” and it certainly did.
It seems as though with the limited robot-robot interaction, we don’t need the large, defensive powerhouse that FRC generally sees.

Could it be possible that mecanum drivetrains are the ideal way to go because of their maneuverability?

I would agree with you on the drive. While watching the video, I was thinking that would be the most used and best drive train for this year.

You see those bumps called the scoring platforms? Those are going to going to cause all sorts of headaches for mecanums. 5-wheel strafe drive with the strafe wheel on a pneumatic suspension should work well, I think.

I don’t think there is a need to climb those, just go around them.

This. Mecanums won’t handle the bumps well, also mecanums need a very even weight distribution to work properly, I imagine there are going to be a lot of unevenly distributed robots this year…

I would try to set the center of gravity of the robot with the game piece, so when you lift it’s balanced.

Has anyone looked at the field drawings yet? In the game video it looks like the platforms aren’t that high, and there are ramps all around. How high is the platform, and what is the grade of the ramps?

The incline is 16 degrees, the height is two inches. This is from page 8 of the game manual. These values are nominal but the official values are in the field drawing.

Whenever we did mecanums, we always had suspension on each wheel so that all wheels were always in contact with the floor. They even went over the humps in Breakaway just fine!

The angle of the ramp is 16 degrees, and the ‘hypotenuse’ is 7.125 inches. 7.125*sin(16) works out to 1.96 inches.

My guess is this won’t be a major issue with a properly built and driven mecanum.

For the record, we tried mecanums in 2008 and 2009, and just the plywood under the carpet would make things go wonky if you were trying to do a precise alignment.

I’m not saying they’ll be undriveable, I’m just saying they’re going to make auto and certain precision tasks a wee bit more challenging and error prone than they need to be.

My prediction: There will be mecs that struggle mightily and those that dance like olympic figure skaters.

From our team’s experience, the only time that mecanums have ever had troubles were on the bridges in 2012. Even then, the problem was the lower coefficient of friction rather than getting up on them, and we were still able to balance 2 robots better than most teams.

It was the same for us. We used mechanum in 2012 and our only problem was staying in one place on the bridge. We had no problem going up and down it while at an angle.

Amen to this. The only trouble we had with mecanum was the bridges in 2012. It wasn’t impossible, we still balanced. Since it’s only a 16 degree angle, it shouldn’t be impossible to get over it.
Breakaway year, they had larger bumps. We went up them fine with mecanum also. Given, they were carpeted.

Some teams will struggle with the mecanum, some won’t.

never used macanums before but really considering it this year. what is the prefered gearbox for these?

If you have not prototyped mechanum or done it before, I would not recommend bringing it out this season. It doesn’t seem difficult at first, but you will end up spending far too much time on your drive train instead of allocating proper time to your mechanisms.

Our team has had a good amount of experience with mecanums, and we haven’t any big problems with bumps. We used them in 2010 (w/o suspension) and were able to climb over the bump, and also in 2012, where we were able to easily climb the bridge.

Based on that experience I think driving over the scoring area won’t be a problem at all.

the code is for the most part available if I am right so i believe if I give my programmers a macanum chassis early they will make it work. I dont see any serious mechanical issues as long as I get the best ideas from this forum.
Your thoughts on that?
again what is the prefered transmission?