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There are several advantages to powering a robot with ambient
vegetation. The energy content of vegetation is relatively high -- plant
carbohydrates (sugars and starches) have about the same energy density
as lithium batteries; digestive mechanisms can be made light and
compact (as nature testifies); and vegetation is very widely
distributed in both time and space. Several labs around the world
are exploring the option, which so far is understood as tapping
into the electron transport chain stimulated by the microbial
fermentation of some carbohydrate. These electrons are then
organized around one end of the circuit, making in effect a
microbial fuel cell. Machines competent to extract energy from
this source could live off the land unattended for years at a time.
Applications are not hard to imagine. For the military, guns that
live in the forest; for consumers, gardening robots that rake, weed,
trim, and prune, and feed themselves with the results of their labor.
Environmental managers might have a need for autonomous mobile sensor
platforms that could both respond to requests to visit given sectors
and then establish a working presence in those sectors for long
periods. Perhaps the most ambitious application would be designing
ecological links as needed, such as a machine for detecting and eating
"foreign species" (however that is to be defined), or accelerating
nutrient cycles.
Such a device would need a sense of taste to make sure it did
not accidently eat something toxic to its fermenters; the problem of
long-term autonomous maintenance remains unsolved; some policy needs
to be worked out wrt robot poop. However, there do not seem to be any
shoestoppers. See www.gastrobots.com.
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This archive was generated by hypermail 2b29 : Mon Oct 02 2000 - 17:37:08 MDT