Primary Program Objective
The primary objective of the Insect Cyborg Sentinels Project is to develop cybernetic insects for the purposes of living surveillance and reconnaissance micro-air vehicles, MAVs. By eliminating the energy needed for flight and focusing energy efforts on controller and sensor packages, a cybernetic MAV, or CMAV, can be harnessed for the purpose of long endurance stealth missions.
The work being done at the Labratory for Intelligent Machine Systems focuses on the power generation systems of the project, with our collaborating researchers focusing on the control and communications systems.
Technical Approach
Our approach to power generation is to use power harvesting, also known as energy scavenging. The field of renewable energy systems has been growing for quite some time now due to various driving concerns, ranging from natural resource depletion to longer lasting wireless systems, etc. The focus of that work has been to characterize and produce renewable energy storage devices that recharge based on converting energy from the local environment. Examples within this broad definition can range from solar cells, to RF receivers, to thermoelectric devices, to vibration-induced generators.
When evaluating each of these devices for the purpose of creating an energy source for hybrid insect electronics, the motion of the flight was identified as a large source of energy that should be investigated for use with the vibration-induced generators. While the other types of power harvesting devices do have their merits, the vibration-induced generators will operate when the hybrid insect is in flight, allowing sensors, actuators, and communication systems to be active for achieving the program’s primary objective.
Vibration-induced generators can be constructed to use piezoelectric, electromagnetic, or electrostatic effects to generate electricity. Devices based on these power harvesting methods are among the best options for CMAV power generation as each of these systems can be made relatively small (sub-one gram) to be carried by such hybrid insects as “payloads.” Within the Garcia Group, primary research interests have been in the design of these devices for the specific tuning of power density (Watts/kg). Also, energy management circuitry to efficiently condition these AC signals to storable energy is being developed.
Energy Harvesting "Backpack"
We have developed a system that harvests energy using the piezoelectric effect, and are currently refining and optimizing the design while continuing to explore additional possibilities for power generation. The current design incorporates a single piezoelectric element mounted on a double beam. The natural frequency of the double beam is tuned to approximately the wing-beat frequency of the moth. This results in high amplitude vibrations of the beam (kinetic energy), which is converted to electricity by the piezoelectric element.
Current Results
Our energy harvesting system is currently capable of producing approximately 3mw peak, and 25μW rms. By tuning the natural frequency of the double beam to more closely match that of the moth's wing-beat frequency, we expect to achieve substantial gains in power generation.
Please visit our Media page for some photos and videos of the energy harvesting system, as well as our acceleration logger and power logger.
PDF of project overview. (presented at SMASIS 2009)
Media Coverage
"Bugging the Bugs," AWST, January 12th 2009 [link to pdf]
"Insect Cyborg Sentinels." Journal of Young Investigators, July 18th, 2007
"Autonomous insect cyborg sentinels," ZDNet.com, June 22nd, 2007