View Full Version : You've Never Seen a Robot Drive System Like This Before

Ron Czapala
09-18-2011, 11:38 AM

What you're looking here is a hemispherical omnidirectional gimbaled wheel, or HOG wheel. It's nothing more than a black rubber hemisphere that rotates like a spinning top, with servos that can tilt it left and right and forwards and backwards. Powered by this simple drive system, the robot that it's attached to can scoot around the floor in ways that I would have to characterize as "alarmingly fast."
Before I go on about the design, have a look at just what this thing is capable of. Its creator, Curtis Boirum, a grad student at Bradley University, in Peoria, Ill., demoed it at the 2011 RoboGames symposium (http://robogames.net/symposium/):


09-18-2011, 12:43 PM
Very nice find Ron,Thanks

PJ Allen
09-18-2011, 12:49 PM
How does this do in a controlled sense, simply navigating pylons?
It does a lot of spinning -- OK, spinning and tumbling.
There are known "issues".

[Also, Boirum acknowledges that it's an old idea.]

Bill Chennault
09-18-2011, 03:04 PM

Pretty amazing. I wonder what would happen if there were THREE hemispheres and the outboard wheels were ditched?


09-18-2011, 05:30 PM

Pretty amazing. I wonder what would happen if there were THREE hemispheres and the outboard wheels were ditched?


Also my first question on seeing the video.

09-18-2011, 05:57 PM
Did someone say HEMi ?
Nice find Ron

Bill Chennault
09-18-2011, 07:51 PM

Did someone say HEMi ?:) :) :)


09-19-2011, 12:02 AM
Hello Bill...
A little different hemi than where use to, But a cool one at that.
I think it should be called a SPHERICAL drive since it runs on the out-side of the wheel and not the inside.
Heres the difference between outside and inside

Bill Chennault
09-19-2011, 12:29 AM

Those are the most beautiful pictures I have ever seen in my life. Sox and Martin should be immortalized.


09-19-2011, 12:43 AM
Pffftttt! Only two valves per cylinder!

Just kidding!

That drive system reminds me of the Voith Schneider (http://en.wikipedia.org/wiki/Voith_Schneider_Propeller) drive. Someday I'd like to build a wheeled version... someday.

WBA Consulting
09-19-2011, 04:03 AM
That is really unique and very clever. One idea that comes to mind to utilize the concept is to use it for the positioning mechanism for a piece of paper in a drawing machine. Have the mount for the HOG wheel fixed mounted with a piece of paper under the wheel and then also have a pen fixed mounted over the paper. The HOG wheel could move the paper around while the pen lifts up or down to draw. Might have to use 2 HOG wheels to prevent errant travel of of the paper with one wheel's tilt adjustments.

09-19-2011, 12:46 PM
We discussed this back on the Robotics sub-forum a few months ago. I thought Erco's reply was pretty funny: