Re: Team 20`s Robot design.
 

..............per wheel?

really?

Re: Team 20`s Robot design.
 

Ya it might be like 7.8 something but ballpark range of 8 pounds.

Re: Team 20`s Robot design.
 

:confused: The AndyMark 8" Mecanums are listed on their Website at 2.5 pounds per wheel, and the 6" wheels are only 1.25 pounds. Do yours really weigh three times as much as the 8-inch AMs? Just wondering...

For a comparison, a mid-90s aluminum 14-inch wheel (without tire) for a Mazda Miata weighs about 11 pounds, and a 14-inch BBS wheel for the same car only weighed 8.5 pounds. Those are MUCH bigger than your robot wheels. I'm guessing that your wheels weigh eight pounds for all four.

Re: Team 20`s Robot design.
 

Nope they are. they were made by a 7x7 solid block of aluminum and was milled out. This also includes the rollers and the bolts that hold the rollers on.

Re: Team 20`s Robot design.
 

Hes right they are roughly 8 ponds per wheel.

Re: Team 20`s Robot design.
 

Wow, 8lbs per wheel!

How did you guys make weight with both the Arm and the Puncher modules?

Re: Team 20`s Robot design.
 

my bet is that they saved a ton of weight by using those hokey sticks for there arm.

Re: Team 20`s Robot design.
 

IT WAS CLOSE!! and we ended up not wanting to use the poker in nationals so we did not even get it weighed with robot so we had about 10 pound leeway. And the hockey sticks were a real weight saver. they are light and strong and has a little flex to them. But once again thanks for all of the positive feedback we worked really hard.

Re: Team 20`s Robot design.
 

I would really like the CAD files for the wheels. I talked to someone on the drive team and they said they could email them to me. so if someone...anyone could please contact me from team 20.

thanks

Re: Team 20`s Robot design.
 

Coosty,


I justed emailed our CAD head mentor and if you could send me a message of your email i will give it to him and he can email you the files.

Re: Team 20`s Robot design.
 

Also we have a back up wheel and if anyone is gonna be at Battle Cry at WPI you can see it at our pit.

Re: Team 20`s Robot design.
 

CORRECTION!!!!!!! all of the info i have been getting it False and i have been getting it from EERic. The Wheels actually weigh around 2 pounds and eight all together. Sorry for all of the False information.

Re: Team 20`s Robot design.
 

Do those macanums work well? What makes it different from other macanums? (I obviously see the difference, but any difference regarding why it works better?)

I've been hearing macanums slow down the robots, but I think this directly proves it wrong?

Thanks,
keehun

Re: Team 20`s Robot design.
 

I'm not on team 20 but I can answer a few of your questions. I don't think mecanum wheels are substantially slower and any speed lose comes from the lower efficiency of the wheels themselves.

Re: Team 20`s Robot design.
 

In theory, a robot using its mecanum wheels will travel at 71% the speed of one the using normal wheels (assuming both robots are geared the same, and the wheel sizes are the same), because wheel is designed to deliver force at a 45 degree angle to its axis of rotation, and thus some of it is being wasted pointing off in the wrong direction. On the other hand, a mecanum robot can travel forward, sideways and every 2-D vector in between, which provides it the maneuverability to get around obstacles much quicker than skid-steer or Ackerman robots.

In reality, the roller's bearings aren't perfect so a mecanum robot's forward speed tends to be a touch higher than its sideways speed. I don't know the actual difference, and it would be really dependent on loading and the specific wheel's bearings. I suspect if one used decent needle bearings on the rollers, the forward/sideways difference would all but disappear.