Mecanum Drivetrains

[pfreivald]

Originally Posted by Lil' Lavery

Being able to execute a "roll" maneuver is pretty much the tempts me towards omni-directional drivebases (and some fine tuning near goals like 2005, 2007, or 2011). That being said, I don't anticipate it happening anytime soon on 1712 and it's only useful if the field has enough space for it to be executed (so it rarely solves choke point defense). 1640's swerve drive roll maneuver is probably my favorite, though. So beautifully executed this season.

In terms of actual competitiveness, I wouldn't recommend straight mecanum for teams seeking to become elite. Some kind of omnidirectional drive combined with high-torque pushing is, I think, the best of both worlds, and of those kinds of drives, octocanum has been the best solution for us so far--it's certainly a lot simpler and lighter than swerve.

[wilsonmw04]

Originally Posted by pfreivald

In terms of actual competitiveness, I wouldn't recommend straight mecanum for teams seeking to become elite. Some kind of omnidirectional drive combined with high-torque pushing is, I think, the best of both worlds, and of those kinds of drives, octocanum has been the best solution for us so far--it's certainly a lot simpler and lighter than swerve.

no matter how accurate your statement is, mecanum is a great solution for many small teams. They are easy to build. They are easy to drive. They give young and/or small teams a reliable with a relatively small investment.

Octocanum is a wicked drive train. we developed a version last summer, Ran it with some success last year and perfected it this summer. I really hope the game allows us to use it this year.

[pfreivald]

Originally Posted by wilsonmw04

no matter how accurate your statement is, mecanum is a great solution for many small teams.

I disagree. They're a neat application for many small teams (trust me, it doesn't get smaller than 1551, or at least not by much). For competitive advantage, the KBOS is a better solution for those who can't to octocanum or some other variant which provides pushing/shoving/defense/plowing-through-defense capabilities.

Originally Posted by wilsonmw04

Octocanum is a wicked drive train. we developed a version last summer, Ran it with some success last year and perfected it this summer. I really hope the game allows us to use it this year.

It's a rare game that won't. We're very happy with ours, but I'd love to see how you've "perfected" it.

[wilsonmw04]

Originally Posted by pfreivald

It's a rare game that won't. We're very happy with ours, but I'd love to see how you've "perfected" it.

Not to hijack the thread, but... :-)

Here is our prototype last summer

http://www.youtube.com/watch?v=QPBly4Hin9o

We have two major issues:
1. The chain kept jumping/ alignment issues during shifting

2. There was so much tension on the chain that is was stretching and needing to be replaced every few days.


We did some mods with the piston and changed from #25 to #35 chain. Created spacers to fix the small alignment issues and we now have a pretty darned good drive train. We had rookies driving it this fall and went through 10 or so off season matching without a chain coming off or any major issues. We are looking at optimizing the weight of our modules, but I am pleased with the results:

http://www.youtube.com/watch?v=oBP3pLThZls

When I stated I hope the game allows us to use the octocanum, I'm hoping not to have large obstacles to traverse like Breakaway or Rebound Rumble.

[yash101]

The idea of locking mecanums is a great idea and I will share it with my team. We were going to switch to Swerve/Crab because it gives a greater traction, allowing the robot to defend well. This will allow us to implement a "Defend Mode" or a "Hybrid mode", where the root automatically switches after the wheel RPM reaches a certain amount!

[pfreivald]

Originally Posted by wilsonmw04

Not to hijack the thread, but... :-)

We reduced the weight of ours like crazy by using 2" Colson wheels and belts instead of chains. The difference in wheel size allowed us to get a 5:1 reduction in mecanum vs. traction drive with very, very little weight or complexity.