What’s better than a caster? An omniwheel. These wheels are like a big wheel with little wheels at different angles that can roll in any direction. [Sonodera] built an omniwheel out of laser cut MDF. MDF–or Medium Density Fiberboard–makes up all the parts of the wheel. There’s no plastic or metal at all.
[Sonodera’s] wheel is more of a passive design like a caster. It would be possible to drive the wheel through the center in two directions, but the right-angle rollers are passive.
We’ve seen several robots with omniwheels before. In fact, this tripod-inspired robot also has passive rollers and the three-legged design takes advantage of them (the so-called Kiwi drive). Some schemes combine multi-directional wheels with conventional wheels (usually the standard wheels are in the center). There are other multi-directional wheel designs out there, including the Mecanum wheel. You can see a video of the MDF wheel in action, below.
Very nice! I would like to see it in action on a robot though. One of the odd benefits of MDF is that the surface is somewhat slick, so when two pieces rub on their factory surfaces, there is little friction.
Nice build, and good looking to boot.
Best design I have seen has the lateral rollers passive and you simply drive the left wheels foreward and the right wheels reverse to move sideways.
do you mean a mecanum wheel?
cool but mdf for wheels? it’s going to fall apart relatively quickly right?
Oh yeah. Put a few pounds perpendicular to the cut faces and it’ll fall apart. I’m guessing it was for a proof of concept, make sure his design worked before cutting it from something more expensive and useful. Or if he never has to actually use it…
Part of me thinks that waterjetting this out of metal and welding some of it together would actually make something pretty robust, though quite time consuming to actually create.
You may have a bias for waterjetting :)
MDF, A.K.A. termite barf
It seems to me that you would be able to drive these wheels in a direction perpendicular to the axle, but you would still need another wheel to drive them in the direction along the axle. So would you, for instance on your car, fit wheels not just on the sides, but also on both ends?
These are usually setup in threes at 120 degrees from each other. Imagine an equilateral triangle with one of these on each vertex.
Wouldn’t that mean that the chassis would have to be huge to offset a stable point of gravity for any load? In any case i would be interested to see a construction using these wheels on a vehicle.
https://www.youtube.com/watch?v=CjcyHicm3NA
Yes but the mecanum wheels are arranged traditionally, and the rollers are already at a 45 degree angle to the shaft/wheel direction. Shannon was talking about arranging the wheels in an equilateral triangle.
They also seem to make the vehicle shake due to the imperfect circle they form
If you’re interested here’s a project my high school team worked on for a robot soccer competition (Robocup). http://pi.bbcrobotics.org/robots/
All of our robots have used omniwheels. The latest generation of wheels were custom made from scratch (CNCed).
See http://pi.bbcrobotics.org/news/index.php?controller=blog&action=view&category=wheel-assembly