Comments on: Hooray robots!

By: Melanthios

Melanthios — Fri, 05 Sep 2008 21:26:52 +0000

Ditch the webcam and go for sensors that read non-visual input. As humans, we focus too much on seeing. Hamsters navigate by smell, which is why it doesn’t matter to them how scratched the hamster ball gets. How about sonar, instead of a camera? It can read much more sensitive data.

By: Belzeber & Berial

Belzeber & Berial — Fri, 15 Aug 2008 01:40:22 +0000

The thing I find disheartening in the comments is that we seem to move away from the concept of a mostly-sealed and thus mostly-indestructible robot. For example, looking at this, amongst my first thoughts about the uses of this bot was: “I could punt this down a manhole, expect it to survive, and have it carry out diagnostics”. However, the further we move from a sealed system, the more impractical such an idea becomes, and indeed the webcam itself is a massive liability.

By: Matthew Kuzma

Matthew Kuzma — Fri, 01 Aug 2008 20:42:44 +0000

To resolve the spinning issue, you could set up a motor inside the ball with its axis aligned vertically, attached to a small flywheel. Conservation of momentum should allow you to rotate the robot by spinning the flywheel. The precision of your turning should be about as good as the precision of your motor, which is generally terrible. But boy would it look cool.

By: James Phillips

James Phillips — Mon, 28 Jul 2008 06:08:59 +0000

have no desire to build a rolling robot, so I’m not sure I should
comment. I also have no image-processing experience.
I think keeping the camera outside the ball will introduce more
problems than it solves. It may be worth it if it looks “cute.” From
the drawing in the cartoon, I don’t think the camera on top looks
very “cute” at all.
I think it would be interesting if the electronic “hamster” could
move around without the ball as well. (the design depicted relies on
the ball)
Suggestions for mitigating the imperfect ball problem:

1. several “dumb” sensors. They will encounter the same problems as
the camera. They should be cheaper, and can be made into a crude
omni-directional camera. You can even point some at the floor to
watch for tape (or any contrasting) lines indicating stairs or other
rooms.
2. High contrast: ignore all the “grey”. Dark scuff marks may cause
extra trouble, however.
3. Lenses. Blur out the ball by making your bot far-sighted.

PS: I don’t know if this Blag is moderated, or just doesn’t like my
browser.
Edit: Ironicly, the captcha does not show up in my graphical
browser. *shrug*

By: sairahannalisahassalheth

sairahannalisahassalheth — Mon, 28 Jul 2008 00:34:55 +0000

Perhaps a great plastic ball with some textured rubber stops for extra friction, and a round “cap”, if you will, which has a omni-directional mechanical ball, much like one of those things in a mouse pointer. The whole thing would be balanced by a gyroscope (don’t ask me how), and the camera would be up top. The command center would be inside, remote control optional. And this brings up the issue of cooling… it probably couldn’t run for very long periods… but I’m sure it would be only a few short steps to make it amphibious.

By: Ross

Ross — Sat, 26 Jul 2008 01:46:20 +0000

Mecanums? why not just omni-directional wheels? with the set up in the comic, the robot would move at a weird angle. 45 degrees the the x-axis as drawn. with using omnis, coding would be so easy as compared to mecanums. and like you said, price drop. I focus on drive systems in robotics. the only downside to omni’s as opposed to mecanums would be drift. if something were to bump it, it would tend to drift on certain axis.

By: Bruce

Bruce — Fri, 25 Jul 2008 21:12:57 +0000

If anybody revisits this thread so long after its heyday, I would suggest air bearings for the camera on top the sphere. Mount the camera on a yarmulke-shaped hovercraft that fits on the top of the sphere like a yarmulke. Use a magnetic coupling, such as those used to stir things in chemistry labs, to turn a fan, supplying air to the hover plenum. There would still be a need for magnets to prevent the whole thing from sliding gracefully off the top of the sphere, but at least grime would not be an issue, as there aren’t ball bearings. With an appropriate border fringe/skirt, rough sphere surfaces could be compatible.

By: Will Scarlet

Will Scarlet — Mon, 14 Jul 2008 13:24:01 +0000

First, I’m no mechanical engineer. I can’t make or code these things. However, there are a few problems I could probably address.

First, mount the camera inside the ball as close to vertical equator as possible. The curve there is no easier to look through than at any other point in the sphere, but it solves a few little quirks, like odd angles in viewing, and where to put the camera so that it doesn’t interfere with the motion.

Second, the important thing is the machine itself. the ball is just a casing and can be replaced when necessary. Keep a few on hand, and just swap them out when the video is no longer clean enough to be any fun. Don’t overcomplicate a simple thing, m’friends.

Now, this solves a couple of primary problems, let’s fix a secondary. The camera mounting is stable and secure, though being fixed to the machine will give it more bounce. How do we fix this, you ask? We handle it the same way we would cars, the same way we would cd lense machinery. Put it on a shock absorber. Heck, egg crate foam would serve as a stop-gap for this purpose.

Good luck.

By: Shingkai

Shingkai — Tue, 08 Jul 2008 22:54:07 +0000

I realize that quite a few people have addressed the wheels and I know this post is a bit (really) late, but instead of four mecanum or four omni wheels, I’m fairly certain that with the proper arrangement, full rotation and translation can be achieved with only three omni wheels, as featured in a display for the new FIRST controller system at the championships in Atlanta.

By: Tim McNamara

Tim McNamara — Sat, 05 Jul 2008 00:16:22 +0000

For noob such as myself, a pretty fun application of this sort of robot is available here: http://www.buzzball.net/