Quote:
Originally Posted by BVespone
Dear FIRST members,
I hope everyone has had a great build season, and I wish everyone luck at the upcoming regional events. Team 3015 decided to use mecanum wheels this year, and due to the limited availability on Andymark, we actually built our own wheels with the help of our mentors and our Sponsor Getinge, which provided some machining capabilities (laser cutting) that are not available in our school. For my Senior Engineering Class, I am researching a method by which high school FIRST teams can fabricate mecanum wheels utilizing only the tools in their school shop, and parts from a hardware store. I am hoping that I can get some help from the FIRST community with my research by having FIRST members answer these quick questions in this thread:
1. Which of the following tools do you have access to?
a. Drill Press b. Band Saw c. Miter Saw d. Lathe e. Welder f. Laser Cutter (please list any additional tools you think are important)
2. If you have used mecanum wheels in the past, have you ever created your own?
3. What do you believe is the most challenging aspect concerning the creation of the mecanum wheels?
Thanks Everyone!
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Noble goal, not sure but I think you could check out the behind the design books looking for 357 or Jester Drive. (Or in the CDM archives) They might have some interesting solutions. Also search for VEX Mecanums here on CDM too, some people have done some cool stuff with VEX that might be worth checking out for ideas.
397 has: Drill Press, Band Saw, Chop Saw, Lathe, Welder, Mill
2337 has: Drill Press, Band Saw, Chop Saw, Lathe, Welder, Mill (Numeric Control and manual)
The real benefit of these tools is that they must come equipped with an operator who knows how to work them.
2337 has used Mecanum wheels in 2008 and they purchased them from AndyMark. 397 has never used Mecanums but they also purchased a set from AndyMark.
The most challenging aspect of Mecanum wheel fabrication would be making the proper rollers IMHO. This could be overcome by molding your own set using a process similar to 125's wheels this year. This would allow the user to fine tune the hardness of the urethane and thus the "grippyness"* of the wheel to their specific needs. The downside would mean that teams would have to understand not only the process but how an increase coefficient of friction would effect their drive train. I have a theory (that hasn't been proved by me looking at the math) that in the case of Mecanums more grip is not always a good thing and that there is a sweet spot for FRC competition. If this could be experimentally or numerically discerned and an appropriate roller design made publicly available I think the difficulty in manufacturing Mecanum wheels could be drastically reduced.
*"grippyness" is really coefficient of friction but I think I prefer that word because it is very blunt.