Utah Mine Disaster and Robots

Or trail a wire behind it, like the Navy does for torpedoes.... Much simpler than dropping RF repeater nodes, that would have to powered, etc...

-mpm

I've seen deep bore ice drills where they have plenty of electrical cables going down to the head, but a thick metal cable supports the entire weight of the head and every 50' or so they attach a clamp to relieve stress on the cables.

I would certainly agree that fiber is a superior solution, though. :-)

Did you also see that it took a full day to cut a road and move one drilling rig to drill the third hole?

Since the power goes into the cable at the far end, you have to provide it down the cable along with the motor power.

One of the problems with making such a system would be finding a coax that liked repeated flex.

I don't think RF would be very good through all that rock. You would have to go down to only a few Hz or few tens of Hz to get through.

Take a look at SouthBay 41323 cable.

There is no great risk of stretching it. There is also no risk of ever lifting it either but it is obviously more than is needed for this job.

Up to a point, adding the wires for power is better than adding the batteries. If you are willing to lose more power in the cable than you deliver to the load end, you don't need very big wires.

"Joel Kolstad" wrote in news: snipped-for-privacy@corp.supernews.com:

these days you would use a DIGITAL video signal,and a fiber optic link for it.You can do kilometers easy with fiber video. You could get better resolution,too.(higher BW)

"Paul Hovnanian P.E." wrote in news: snipped-for-privacy@seanet.com:

I know it's sci-fi,but have you ever read James P.Hogan's Bug Park? In that book,they made tiny robots that crawled like bugs,with RF remote control.Some were bug-sized,some with soupcan sized.You could have relay drones,too,for a longer comm link.

also,any airborne bot would stir up the coal dust and ruin your video,if it didn't ignite the airborne coal dust and cause a terrible fire/explosion.

Hi MooseFET,

I was kinda hoping that one might be able to use the bored hole that has relatively well-controlled dimensions as something of a waveguide, but I realize this is probably pie-in-the-sky thinking and not at all practical. :-)

Hey, wait, if we might the frequency high enough... oh, right, then we're back at fiber optics. OK!

Don't they have absurdly pure fiber that has losses that's something ridiculous like 1dB/mile? In the optics class I took in college I probably briefly knew the number, but all I remember now is that it completely blows away anything based on copper. :-) Being able to look through a window that's a mile thick and not having any significant loss is really amazing...

If it was an r/c helicopter, yes.

A little blimp with fans probably wouldn't do much stirring.

Explosion could be a concern... maybe tiny induction motors, or brushless motors with permanent magnet rotors?

This all could make an interesting robotics contest. Have divisions based on the diamter of the bore hole used for deployment. Probably hold it in some kind of mining museum not too deep, so that you could access the contest course (Newgate Prison (retired copper mine) in CT for example)

You dangle a piece of oax down the bore hole and hand an antenna into the mine at the bottom.

Right. You are going to want something slow so as not to get it tangled up in junk at the bottom. In addition, if the r.f. video link gets long and lossy, the system can revert to slow scan. If so, the operator will need additional time to react to situations. Not easily done with an airborne vehicle or a fast ground vehicle.

There's also the energy efficiency and battery life of various options to consider.

:-)

^^^ Better yet, use coax. It has lower loss per meter than oax. ;-)

Nothing in real life will make a good waveguide. The dirt likes to eat RF. Something like a coal mine would be extra bad because it has many layers. It would be like your cable changed every few feet. Much of th eRF power would be scattered.

Go higher. The more energy in an Xray the higher the frequency. High energy Xrays are used to inspect big metal things.

Far lower figures in single mode fiber.

Andrew

MooseFET snipped-for-privacy@rahul.net posted to sci.electronics.design:

So they did, oops.

That is one approach, some use fiber optics to eliminate the video degradation issue.

Joel Kolstad snipped-for-privacy@yahoo.com posted to sci.electronics.design:

MooseFET snipped-for-privacy@rahul.net posted to sci.electronics.design:

However, small and lightweight cameras, efficient light sources and fiber optics add up to an effective package for battery operation and look ma much smaller support cables.

It is the motors that are the real killer.

White LEDs are quite good as light sources. If you don't want color, you can use one color of LED and a camera that is very good at that wavelength. You need to be able to aim the camera and lights. This suggests either motors or multiple cameras and lights.

Wheels and treads that work well on a lumpy loose surface tend to be lossy. You want a soft rubber surface covering enough area that one pebble rolling won't prevent you from going.