Team 20`s Robot design.
 

I talked to team 20 at nationals and I absolutly loved the design and was wondering if someone from team 20 that has access to the cad files could pm me.


thanks!

Re: Team 20`s Robot design.
 

Thank you, we worked really hard on our design this year. I can talk to our CAD team and get back to you with the files.

Re: Team 20`s Robot design.
 

I don't have the CAD files, but I would like to comment on the Rocketeers robot.

I loved the mechanum drive. The speed of the robot was impressive and what seemed to be controlled drifting on the turns was amazing. It was a great design along with well prepared drivers. I liked watching your guys robot in Boston. Even though you knocked us out of elims, you guys deserved it. Congrats on a good season.

hope to see you next year in Boston.

Re: Team 20`s Robot design.
 

Thanks on all of the Comments and I am part of the CAD team but i don't have any of the files they are at school on a locked account. But thanks for all of the positive feedback.

Re: Team 20`s Robot design.
 

You can view pictures of Team 20's CAD files at Autodesk FIRSTbase.
http://firstbasefrc.autodesk.com/?nd...ddlastlink =1
Second one down.

Amazing robot by the way, our team was in awe every time you guys played, both at FLR and Boston.

Re: Team 20`s Robot design.
 

I'm thinking Team 20 could make a killing selling those mecanum wheels. Very cool.

Re: Team 20`s Robot design.
 

From the looks of it those are the 6in AndyMark mecanum wheels so they are already commercially available.

MikeM.

Re: Team 20`s Robot design.
 

Almost, they where using the AndyMark wheels but bent the sides plates. So they milled new side plates out of solid aluminum and attached the AndyMark rollers.:D

Re: Team 20`s Robot design.
 

Learn something new everyday. Thanks :D

MikeM.

Re: Team 20`s Robot design.
 

We did get a lot of publicity about the wheels and i don't know how many times i had to explain them to the people in the pits. I am on the Drive team and within the first 10 mins of driving on the andymark wheels on our practice field the side walls near the rollers collapsed in pitching the rollers so they would not roll , the bumps in the middle of the field was what did it. So we took the geometry from the andymark wheels and just redesigned them so they were reinforced. I dont have a picture but we will be at Battlecry.

Re: Team 20`s Robot design.
 

Here is a Picture i got from a mentor taken at the FLR in Rochester

http://i299.photobucket.com/albums/m...93/Mecanum.jpg

Re: Team 20`s Robot design.
 

Those are some really nice looking hubs there. How much did they weigh?


MikeM.

Re: Team 20`s Robot design.
 

Take if from someone who played against them, they were awesome this year. I have always liked this type of mechanum wheel for FIRST robots because it puts a lot more contact area on the floor then the other designs. AM,357,ETC. The draw back to this style is you can't really climb anything. Team 20 definitely had a great robot design though them and 39 made up a killer alliance along with 207.

Re: Team 20`s Robot design.
 

Ah yes, I remember these wheels. I named them "machinist's worst nitemare" :D Do you have any pics of them during manufacturing? They certainly are some of the nicest machined pieces I've seen all season.

Re: Team 20`s Robot design.
 

There is a video of it being made and one of our mentors has it so i will track it down and post it on youtube. But also regarding the weight of the wheels, they are about 8 pounds per wheel.

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.

Re: Team 20`s Robot design.
 

The Mecanum Wheels do help a lot. Not only can they go sideways but coming around the turn at high speed could cause a skipping effect and with the mecanum wheels it makes a drifting motion .

Re: Team 20`s Robot design.
 

Actually, Mecanums will travel with the same top speed as a standard wheeled robot, but only apply √2/2 (≈71%) of the force of a standard wheel. The top speed remains exactly the same as a traditional wheel of the same diameter. With reduced force (and thus torque), acceleration and pushing power will decrease though.

Many teams have also been able to balance their forwards and sideways motion through clever programming tricks and closed-loop control systems. It all depends on how well your machine is built, maintained, and programmed.

Re: Team 20`s Robot design.
 

In addition, maximum force exerted on the carpet (which translates to maximum useful torque) is also typically reduced because the friction coefficients you can get with most rollers that I've seen are going to be less than you can get with better traction wheels.

Re: Team 20`s Robot design.
 

WOW you guys know your mecanum wheels!