AS IN a growing child, a flood of hormones will make robots bigger, stronger
and more independent. By including hormone-like messaging in a robotic control
system, a team at the University of Southern California鈥檚 Information Science
Institute in Marina del Rey has managed to overcome a problem that has been
dogging robotics.
Until now, no one has known how to enable a robot to add new parts to
itself鈥攁 process called 鈥渟caling鈥�. Robots with this ability could explore
deep space independently: shipped to distant planets as a mass of tiny dumb
units, they would build themselves into whatever kind of machinery proved
appropriate on arrival. One of the advantages of these reconfigurable modular
robots would be a high level of 鈥渞edundancy鈥濃�攂its could break off without
wrecking the whole machine.
Behnam Salemi and his colleagues at the ISI have found a way to make such
resourceful robots. These include walking creations that will adapt their gait
if you break a leg off, and others that inch along like a caterpillar regardless
of what length they have become. Both use software inspired by biological
hormones. The team will report on their work at a conference on robotics and
automation in Seoul next month.
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In nature, hormones trigger events in different parts of the body
simultaneously. 鈥淔or example, when a human experiences sudden fear, a hormone is
released by the brain, causing different actions,鈥� says Salemi. Fear releases
hormones that might make your mouth open and your leg muscles twitch into
action. Although the hormone is triggered by the brain, the muscle control is
located in the mouth and legs, Salemi says.
Project supervisor Peter Will says: 鈥淗ormones are propagated signals
that can be modified or delayed鈥攐r which can even disappear along the
way.鈥� This adaptability lets hormones accomplish tasks that a single-destination
message could not.
In a segmented or multi-module robot, a message based on digital hormones
will reach all connected sections. The hormone message tells all modules about
the condition of the others without carrying specific commands. Each module can
then interpret this knowledge in its own way.
Each module is an autonomous unit, with its own on-board power supply and
motors. The modules connect via simple two-pronged plugs through which the
hormones propagate. 鈥淵ou don鈥檛 even give it information about what gait it
should adopt,鈥� says Salemi. The human 鈥渙perator鈥� just tells the robot which
direction to move and the robot will figure out the best gait, given its current
configuration.