Maker Pro
Maker Pro

Utah Mine Disaster and Robots

  • Thread starter Paul Hovnanian P.E.
  • Start date
M

mpm

Jan 1, 1970
0
Have you looked at the sat photos of the uneven, rocky ground above
that mine?

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

I saw one drill rig on TV, but the terrain looked reasonably flat
where they were drilling.
But not a cakewalk.

My point was there are 6 miners running out of air.
That's not the time to worry about the small stuff.
-mpm
 
M

mpm

Jan 1, 1970
0
The downside of a blimp is that it may get hung up in something without
constant control inputs from the remote operator. A wheeled or tracked
vehicle can move slowly and stop to examine the terrain before
proceeding.


A gerry-rigged system might only have a few hundred yards range inside a
mine. But that's a few hundred yards further than they can see now.

If I were designing such a robot for this job, I'd give it the ability
to deploy some low powered sensor/repeater nodes that form a mesh
network. As the robot reaches the limits of its comm range, it just
drops another node. These nodes can be equipped with some sensor
capability in addition to their networking function (in the event a live
miner walks by) and can provide some navigational data based on how the
network configures itself.


Pre-position some mesh network nodes, connected to a power and comm
buss, but with a low power, battery backed up mode. That way, if the
feeds become severed, they begin autonomous operation. During normal
mine operation, they provide normal operations networking functions.

If a standard can be developed for such devices, than communications and
rescue equipment (both walkie-talkies and robots) can be designed to
take advantage of existing nodes in place and new nodes only need to be
deployed to bridge damaged areas.

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
 
J

Joel Kolstad

Jan 1, 1970
0
mpm said:
The weight of coax (1700-feet unsupported) will probably stretch it
out like a angle hair pasta.

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. :)
 
M

Michael A. Terrell

Jan 1, 1970
0
mpm said:
I saw one drill rig on TV, but the terrain looked reasonably flat
where they were drilling.
But not a cakewalk.

My point was there are 6 miners running out of air.
That's not the time to worry about the small stuff.
-mpm


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


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
M

MooseFET

Jan 1, 1970
0
At some point you're better off going wireless since the power loss follows
1/R^2 rather than exp(-kR) as it does for coax cables.

In coax it's eventually the power that limits you. Something like LMR-195
(RG-58 size -- ~0.2" diameter) is ~0.8dB/100ft. at 5MHz (plenty for reasonable
video images), so that's 45dB loss over 1.7km -- still quite workable starting
with modest power levels (and RG-58 will handle plenty of power... of course,
getting that power into the cable is another matter).


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.
 
M

MooseFET

Jan 1, 1970
0
It would almost have to be fiber anyway.

The weight of coax (1700-feet unsupported) will probably stretch it
out like a angle hair pasta.
Take a look at SouthBay 41323 cable.

http://www.southbaycable.com/products3.html

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.

I'm thinking a little battery operated camera with an fiber-optic
interface, towed on a small steel cable, also carrying a fiber. I'd
be really surprised if they're doing it any other way.

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.
 
J

Jim Yanik

Jan 1, 1970
0
At some point you're better off going wireless since the power loss
follows 1/R^2 rather than exp(-kR) as it does for coax cables.

In coax it's eventually the power that limits you. Something like
LMR-195 (RG-58 size -- ~0.2" diameter) is ~0.8dB/100ft. at 5MHz
(plenty for reasonable video images), so that's 45dB loss over 1.7km
-- still quite workable starting with modest power levels (and RG-58
will handle plenty of power... of course, getting that power into the
cable is another matter).

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)
 
J

Jim Yanik

Jan 1, 1970
0
The downside of a blimp is that it may get hung up in something without
constant control inputs from the remote operator. A wheeled or tracked
vehicle can move slowly and stop to examine the terrain before
proceeding.


A gerry-rigged system might only have a few hundred yards range inside a
mine. But that's a few hundred yards further than they can see now.

If I were designing such a robot for this job, I'd give it the ability
to deploy some low powered sensor/repeater nodes that form a mesh
network. As the robot reaches the limits of its comm range, it just
drops another node. These nodes can be equipped with some sensor
capability in addition to their networking function (in the event a live
miner walks by) and can provide some navigational data based on how the
network configures itself.


Pre-position some mesh network nodes, connected to a power and comm
buss, but with a low power, battery backed up mode. That way, if the
feeds become severed, they begin autonomous operation. During normal
mine operation, they provide normal operations networking functions.

If a standard can be developed for such devices, than communications and
rescue equipment (both walkie-talkies and robots) can be designed to
take advantage of existing nodes in place and new nodes only need to be
deployed to bridge damaged areas.

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.
 
J

Joel Kolstad

Jan 1, 1970
0
Hi MooseFET,

MooseFET said:
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.

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!
 
J

Joel Kolstad

Jan 1, 1970
0
Jim Yanik said:
these days you would use a DIGITAL video signal,and a fiber optic link for
it.You can do kilometers easy with fiber video.

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...
 
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.

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)
 
P

Paul Hovnanian P.E.

Jan 1, 1970
0
Joel said:
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. :)

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

Paul Hovnanian P.E.

Jan 1, 1970
0
Jim said:
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.

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.
 
P

Paul Hovnanian P.E.

Jan 1, 1970
0
Paul Hovnanian P.E. said:
You dangle a piece of oax down the bore hole and hand an antenna into
^^^
Better yet, use coax. It has lower loss per meter than oax. ;-)
 
M

MooseFET

Jan 1, 1970
0
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. :)

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.

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

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

Andrew

Jan 1, 1970
0
Joel said:
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...
Far lower figures in single mode fiber.

Andrew
 
J

JosephKK

Jan 1, 1970
0
MooseFET [email protected] posted to sci.electronics.design:
I thought they said that many feet.

So they did, oops.
At 1700 meters, the video signal in the cable won't look very
good. The cables used for pipe inspecting sorts of things use very
small
coaxes that are quite lossy. The electronics has a high frequency
boost to correct for the cable losses. There are limits on how
much of this you can do.

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

JosephKK

Jan 1, 1970
0
Joel Kolstad [email protected] posted to
sci.electronics.design:
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!

2 inches, 50 mm, that would be about 600 MHz. Fiber is still a
better deal, <1 dB / km. With 30 db dynamic range it goes a long
way without any boosters.
 
J

JosephKK

Jan 1, 1970
0
MooseFET [email protected] posted to sci.electronics.design:
Take a look at SouthBay 41323 cable.

http://www.southbaycable.com/products3.html

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.

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.
 
M

MooseFET

Jan 1, 1970
0
MooseFET [email protected] posted to sci.electronics.design:

[.... Robot in the mine ...]
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.
 
Top