Robotics

Facebook robot crawls along power lines to deliver fiber optic cable

Facebook robot crawls along po...
The Bombyx robot's main body remains level to the ground, while an internal mechanism winds a payload of fiber optic cable around the power line
The Bombyx robot's main body remains level to the ground, while an internal mechanism winds a payload of fiber optic cable around the power line
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The Bombyx robot's main body remains level to the ground, while an internal mechanism winds a payload of fiber optic cable around the power line
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The Bombyx robot's main body remains level to the ground, while an internal mechanism winds a payload of fiber optic cable around the power line

Although fiber optic internet cable has many advantages over metal cable, it frequently has to be distributed underground – this limits its usability. Facebook, however, has developed a robot that could wrap the cable around existing power lines.

Among other things, fiber optic cable allows for higher bandwidth than metal cable, along with faster speed, longer transmission distances and stronger security. And while it sometimes is distributed above-ground via existing power line poles, factors such as exposure to wind, ice and temperature extremes may cause it to sag and eventually break over time.

For this reason, most companies and municipalities prefer to place it underground. Doing so, however, involves digging trenches throughout the city, laying the fiber optic cable inside those trenches (either directly, or within a conduit) and then filling them back in. This is an expensive, disruptive and labor-intensive process, which simply isn't feasible in many parts of the world.

That's where Facebook Connectivity's Bombyx robot is intended to come in.

Taking its name from the Latin word for "silkworm," the device is designed to autonomously crawl along existing medium-voltage power lines, winding a continuous length of fiber optic cable around them as it does so. Plans call for it to ultimately be capable of installing over one kilometer (0.6 miles) of cable within about 90 minutes, utilizing machine vision sensors to automatically make its way around "dozens of intervening obstacles" such as insulators. The functional prototype currently has to be manually guided around obstacles by remote control.

Unfortunately, a 1-km reel of regular aerial fiber optic cable is too heavy to be hanging in one place (within the robot) on a typical power line. For that reason, Bombyx uses a special type of cable that incorporates a lighter-weight braided Kevlar cladding, and that drops the optical fiber count from the traditional 96 down to 24. According to Facebook, this should still be sufficient to serve all of the homes and businesses through which each power line passes. Additionally, the new cable features a special heat-resistant outer jacket – this protects it from being melted or stretched by the high temperatures which power lines often reach.

Although Bombyx is still in development, Facebook Connectivity has already licensed the technology to high-speed internet company NetEquity Networks. The robot can be seen in action on YouTube.

Canada's Hydro-Quebec public utility company, incidentally, has recently developed a line-crawling robot of its own, for the automated inspection of power lines.

Source: Facebook [1], [2]

7 comments
7 comments
Eddy
Here in AUS we have an extensive pay tv network distribution system of HFC cable before they went to satelite, now sold and used where available for our pretend high-speed NBN distribution. This is strung on wires between poles using a similar machine. I hope it will be used again soon to put up fibre cable on the existing wires.
Doug Lough
This does not seem viable. Starting with the fact that now the power companies have to deal with another degree of difficulty. And secondly, by wrapping big the lines it will use 2.5 times the cable, effectively raising the cost and lengthening the transmission distance
Kpar
As a retired telco lineman and fiber splicer, I note this article. The process used to place this cable is very similar to the lashers we used to hang copper and fiber cables from supporting strand for many decades. Most crews placing fiber these days (at least where I live) use "flow-moles", or machines that push through the ground (for distances up to 3 thousand feet) and then pull "innerduct" (a HDPE flexible pipe back to the starting point, and the fiber is then "push-pulled" through the innerduct. Still underground, and better protected from the elements.
Owen McCormack
We've been doing this for years. In the UK there's a power company that has its own Telco and distributes using this method. Facebook haven't created anything new here, probably refined the janky robot. But definitely not a new idea.
Nelson Hyde Chick
Doug Lough wrote, "lengthening the transmission distance," like that really maters for something that travels at the speed of light.
noteugene
Fuzzy math Doug. You don't explain how you came up with those hypotheticals.
Expanded Viewpoint
This is not anything new here. Back in about 1997 or so, Southern California Edison was wrapping fiberoptic cables like this on our transmission lines. The crawler was powered by a gas engine and it was adjusted to make one wrap of fiber per some number of feet of travel. About thirty feet of fiber was left free at each end of a span so splices could be made in a junction box mounted to the tower. I thought that it was a huge waste of everything, because it could have been done much more cheaply if they had just used stainless steel clips like are used for brake and shifter cables on bikes, placing them every 2-3 feet. Or hose clamps!