Looking at the Lines
When utility workers need to inspect transmission lines,
they usually either move along the lines while dangling in
special trolleys or peek at them from afar using binoculars.
Neither method is exactly ideal. The former exposes them to
as much as 735,000V of electricity, and the latter makes it
easy to miss small but serious faults. However, Hydro Québec
( www.hydroquebec.com) — a major provider of electricity
to the US Northeast — has developed a robotic solution that
goes by the name of LineScout. It presently uses five of them
to maintain 18,000 miles of distribution lines. Its development
required solving some interesting problems, including the
need to withstand voltages that can easily fry electronic
circuitry and interfere with radio control systems. It also has
to withstand extreme weather conditions encountered in the
northern areas of Canadian provinces. Perhaps the biggest
challenge though was enabling it to maneuver past such
obstacles as cable separation devices, porcelain insulators, corona rings, and the orange balls used to ward off low-flying
aircraft. This is accomplished using pincers that allow it to lift its wheels off the powerline and swing them to the other
side of an encountered obstacle. LineScout is actually controlled by a ground-based operator who makes use of its video
cameras (four standard and one infrared) to detect hot spots and other defects. Via its robotic arm, the unit can also wrap
and clamp frayed wires, measure resistance in splices, and even tighten bolts on equipment that is clamped to the wires.
All of this adds up to a hefty load of equipment; LineScout weighs in at nearly 250 lb (112 kg). Nevertheless, it can scoot
along at 1 m/s ( 3. 3 ft/s) and operate up to five hours between battery charges.
A LineScout inspection bot crossing an insulator string.
Not Ready For The WTTC
When you talk about serious world-class
table tennis, you're usually talking about the
Chinese. It's therefore not particularly
surprising that the first pair of serious ping
pong playing robots has emerged from
China's Zhejiang University
( www.zju.edu.cn/english). "Wu" and
"Kong" — two life-size humanoid robots —
are programmed to serve, return, and keep
score. They track the balls using eye-mounted cameras, predict their trajectory,
and respond with the appropriate shot. The
cameras — operating at 120 images per
second — send images to the bots'
processors which calculate the ball's position,
speed, angle, path, and landing position in
50 to 100 ms, with an error margin of just
2. 5 cm. The machines are capable of playing
against humans as well, and one bot vs. human exchange involved crossing the net 144 times. They do have a long way to
go before being ready to compete in the World Table Tennis Championship since they are not yet capable of advanced
shots like curves, shanks, and slices. SV
"Wu" and "Kong" battle it out in ping pong.
SERVO 02.2012 9