My team wants to make an omni drive for the new compatition but we don’t know where to start. I was looking around and the design that uses 4 all on 45 degree angles looks good for us, how might we build it?
I think you’re referring to an X-holonomic drive train which has omni wheels at all 4 points of the X. The hardest part you’ll have with this will be to keep the omni wheels at the perfect angle so that you can drive and strafe straight.
We utilized an X-holonomic drive this year and we found the most success in using the 45 degree gussets to ensure that the wheels were at the angle we needed. We used the gussets to create an octagonal base and then put the wheels at the 4 corners.
It really is a neat drive! Good luck
Here’s a link to the 45-degree gussets: http://www.vexrobotics.com/products/accessories/structure/275-1186.html
The two best holonomic robots I’ve seen recently are 1492z in 2011 and 44 in 2010. Find some video of Green Eggs (2010) and check out their fold-out wheels – this mechanism was REALLY impressive. (Two members of the winning alliance at Worlds in 2011, as a matter of fact.)
Also, check out Smartkid’s tutorial on holomonic controls…