DARPA invents new flying bug

From: <ber..._at_netaxs.com>
Date: Mon, 21 Feb 2011 13:22:18 -0500

-Ed


Cyborg Moth Gets a New Radio
Research reported this week advances the goal of turning insects into
unmanned aerial vehicles

By Sally Adee / February 2009
PHOTO: CYBER-MOTH by Alper Bozkurt, Boyce Thompson Institute

Electrodes and a control chip are inserted into a moth during its
pupal stage. When the moth emerges the electrodes stimulate its
muscles to control its flight.

10 February 2009?Attempts by the U.S. Defense Advanced Research
Projects Agency (DARPA) to create cybernetic insects (hybrids of
biological and electronic bugs) have yielded ultralow-power radios to
control the bugs? flight and a method of powering those circuits by
harvesting energy, according to research that will be reported this
week at the IEEE International Solid-State Circuits Conference (ISSCC)

Two papers being presented at ISSCC reveal the latest initiatives in
the DARPA-sponsored Hybrid Insect Micro-Electro-Mechanical Systems
(HI-MEMS) project, which is currently in its third year. The program?s
goal is the creation of moths or other insects that have electronic
controls implanted inside them, allowing them to be controlled by a
remote operator. The animal-machine hybrid will transmit data from
mounted sensors, which might include low-grade video and microphones
for surveillance or gas sensors for natural-disaster reconnaissance.
To get to that end point, HI-MEMS is following three separate tracks:
growing MEMS-insect hybrids, developing steering electronics for the
insects, and finding ways to harvest energy from the them to power the
cybernetics.

Researchers at the Boyce Thompson Institute for Plant Research, in
Ithaca, N.Y.?which is one of the contractors on the HI-MEMS
project?presented progress on the first goal at the IEEE MEMS 2009
conference in Italy two weeks ago, describing silicon neural
interfaces for gas sensors that were inserted into insects during the
pupal phase. At ISSCC, the HI-MEMS projects focused on new chip
technology for the second two goals: Researchers led by DARPA
contractor MIT will present a low-power ultrawide-band radio, a
digital baseband processor, and a piezoelectric energy-harvesting
system that scavenges power from vibrations.

The HI-MEMS project was conceived in 2005 by program manager Amit Lal,
an electrical engineering professor on leave from Cornell University
while he coordinates the four-year DARPA effort. MIT is one of three
major contractors, including the University of Michigan and Boyce
Thompson. The research also draws on the work of entomologists,
electrical engineers, and mechanical engineers at the University of
California, Berkeley, the University of Arizona, and Washington
University in St. Louis, Mo. To be considered successful, the final
HI-MEMS cybernetic bug must fly 100 meters from a starting point and
then be steered into a controlled landing within 5 meters of a
specified end point. On landing, the insect must stay in place.

The electronic and MEMS components of the system must consume little
power and be absolutely featherweight. After all, an average hawk moth
weighs 2.5 grams; with too much extra weight it would be unable to fly.

Anantha Chandrakasan, an electrical engineering professor at MIT, is a
coauthor on each of the ISSCC papers. The first is an ultrawide-band
receiver system on chip, a radio that works at extremely low power
over a broad swath of spectrum. (Earlier research had created the
transmitter.) The device was specifically built for the HI-MEMS
project in order to steer the moth. To control the moth?s flight
direction, Chandrakasan and MIT graduate student Denis Daly designed a
small, lightweight, low-power radio connected to a tungsten
4-electrode neurostimulator. When this radio picks up the right
commands, the device stimulates the nervous tissue in the moth?s
abdominal nerve cord. The stimulation makes the moth?s abdomen move in
a way that alters the direction of its flight. The radio and
stimulator are powered by a hearing-aid battery.

The second chip is a low-power digital baseband processor that can
very quickly synchronize with wireless signals. That solves a
particular problem with wireless communication. ?When you send a piece
of data through a wireless link, the receiver takes some time to lock
to the transmitter,? Chandrakasan says. ?Our new algorithms can very
quickly synchronize, which means that you can turn on the radio, take
the piece of data, and then turn the radio back off very quickly. That
saves a lot of power.?

A third chip being presented at ISSCC, which Chandrakasan says is
unrelated to the radio chips and not funded under HI-MEMS, could
nevertheless be used to meet the DARPA project?s goal of finding ways
to efficiently harvest energy from the moth. While a cyborg insect
would be fairly autonomous and self-fueling, there would be no way to
recharge its equipment payload on missions. Batteries are heavy. So
the researchers are seeking a method by which the insect?s flight
itself generates the electrical energy the payload electronics
require. Harvesting ambient vibration energy through piezoelectric
means?in which energy is converted between mechanical and electrical
forms?could supply between 10 and several hundred microwatts of power.

The research presented at ISSCC addresses a common problem with
energy-harvesting circuits: The power consumed by the harvesters?
control circuits reduces the amount of usable electrical power. The
solution, a circuit called a bias-flip rectifier, improves the
power-extraction capability by ?more than four times,? according to
the paper by Chandrakasan and graduate student Yogesh K. Ramdass.

PHOTO: Alper Bozkurt, Boyce Thompson Institute

CONTROLLED FLIGHT

The moth can be made flap its wings under computer control.

The HI-MEMS project is not the first attempt at creating cyborg
animals. The list is long, including pigeons, beetles, cats, and bees.
Perhaps the most famous example is the cyborg rat. In 2004, John
Chapin, a professor at the State University of New York Health Science
Center, in Brooklyn, demonstrated Rescue Rats. These were lab rats
with neural implants that encouraged them to steer through rubble
piles with a camera and GPS locator to find people. Using a radio
remote control, Chapin stimulated a part of the rats? brains that
mimicked the sensation of being touched on the whiskers. In response,
the rats turned in the direction of the sensation. When they turned,
Chapin rewarded them with a quick jolt of electricity in the pleasure
center of their brains.

Jelle Atema, a biologist at Boston University and at the Woods Hole
Oceanographic Institute, was also funded by DARPA in 2005 to research
steering sharks with similar neural implants. Atema says that while he
applauds the HI-MEMS project for its technical ambition and
engineering virtuosity, he is concerned about its ultimate biological
feasibility: Electronic control would compete with natural brain
processes. He cites some limitations for insects, including a tendency
for moths to approach light sources (the proverbial flames) and a
powerful sex pheromone response that could override attempts at remote
electronic control. ?Pheromones are incredibly powerful,? he says.

In addition, modifying just one moth would be prohibitively
time-consuming and expensive, especially in light of the life span of
the animal, says Atema.

Even if HI-MEMS never produces a working cyborg moth, Chandrakasan
says that the usefulness of these devices is not limited to the
specific DARPA project. You can repurpose the chips for assistive
technologies and implantable devices. In particular, he says, the
energy-harvesting system would be a promising technology for
prosthetic arms, which have a similar problem with weight and battery
life.
Received on Sat Mar 02 2024 - 00:57:19 CST