The idea of producing the world's first miniature intelligence-gathering plane (2.8 inch or 7.4 centimeter wingspan) was proposed three years ago at MIT Lincoln Lab, where researchers sought a way to provide direct access to reconnaissance data for soldiers serving in small military units. An urban foot-soldier could send his MAV to the suspected area and see if there are bad guys there on the screen of his laptop. Advanced versions might even sniff out nuclear, biological, and chemical weapons in hostile terrain. Taking into account all of its capabilities (reconnaissance, navigational and communication subsystems) and its small size, this is going to be a sort of a "flying chip". But getting it off the ground and keeping it there will be the hardest part. Aerodynamic behavior of these devices differs from that of larger, faster aircraft. A popular example says that according to the classical theory a bumblebee should be unable to fly. A hovering craft with rotor blades would require about twice the power of a fixed-wing vehicle. Several teams are therefore evaluating fixed-wing configurations using propellers for propulsion. But other researchers, like those at Georgia Tech, argue that even with a propeller, a conventional wing will not generate enough lift to keep a very small, slow vehicle moving through the disruptive airflow that it will likely encounter. An electromechanical multimode (flying/crawling) insect, known as an "Entomopter" is based around a new development called a Reciprocating Chemical Muscle (RCM) which is capable of generating autonomic wing beating from a chemical energy source. Through direct conversion, the RCM also provides small amounts of electricity for onboard systems and further provides differential lift enhancement on the wings to achieve roll and hence, steered flight.

Others are taking different approaches. After experimenting with conventional fixed-wing, flying-wing, rotary-wing and flapping-wing designs, AeroVironment, Inc. (working in conjunction with UCLA and Caltech) developed Black Widow, a disc-shaped aerial vehicle that launches from a shoulder-carried unit. It features a 2-gram microflight control system for remote operation of the front-mounted propeller and two control flaps. Despite its alien looks, Black Widow is driven by a front mounted propeller powered by a battery. Although it has not yet achieved all of DARPA's criteria, it has been reasonably successful, managing a 16-minute flight at a top speed of nearly 70kph (45mph).

The latest developments in lithium battery technology, which provide the most power for the least weight, could enable electro-powered machines to be used for longer missions. Apart from rather exotic RCM system, people are still relying on fossil fuels as the most efficient source of the power. On the other hand, multimode (flier/crawler and/or walker) devices would be much less power hungry than a hummingbird-type device that remains in the air all the time. Michael Goldfarb and Ephrahim Garcia, mechanical engineering professors at Vanderbilt University, are developing such insect-like robots that can crawl and fly. The key to both crawling and flying motion in their robots will be piezoelectric actuators - the technology used in ordinary pagers. Piezoelectric actuators can turn more than 90 percent of electric power into movement, as opposed to 60-percent efficiency of other motors.

Micro-air vehicles and robots can prove useful in everyday life, apart from military and law enforcement community. They can be used in agriculture, traffic surveillance, civilian rescue, home security, entertainment industry, etc. "Imagine a basketball game: You watch the players from an altitude of twenty feet and thenwithin secondssee them from three inches above the court floor. Then you follow the player with the ball across the whole court, always exactly one foot above his shoulder. You pass him and climb up quickly to one inch above the basket, right in time for the slam." - says Stefan Marti from MIT Media Laboratory. He is developing Free Flying Micro Platform (FFMP) and Papa-TV-Bot, autonomously hovering mobots (mobile robots). His schedule for the long-term development has 8 phases, from FFMP for studying helicopter control, automatic control systems, and automatic hovering to truly intelligent and highly responsible mobot. He proposes the use of micro electric ducted fans for propulsion. They are less efficient than conventional rotors, but the main advantage of ducted fans is that they are hidden in the fuselage. This means that they protect the operator, nearby personnel, and property from the dangers of exposed rotors or propellers, which is particularly important for indoor MAV. This robot is eventually supposed to is supposed to stabilize itself automatically and accept spoken commands such as go up and turn left. Keyence's Gyrosaucer II E-570 is used as the airframe of the robot: it is a very interesting hovering device with four degrees of freedom. These are controlled manually through a 4CH remote control, with limited support from the built-in gyroscopes.

Overall trend in Artificial Intelligence, especially in the area of mobile robots, is to divide the functionality of any single device among various dedicated smaller devices. Do you think that we'll have micro air robots around (and above) us in the near future?

   Site(s) of interest:

• Amphibious Machines
  Amphibious Mesoscaled Aerial Robots Based on a Chemical Reciprocating Muscle for Propulsion.
• AeroVironment
  Unmanned Air Vehicles, including Black Widow and Microbat. Don't miss their High-altitude Solar Airplanes program...
• MUAV
  15 cm, 90 gm air vehicle with an autopilot. From Intelligent Automation, Inc.
• MLB Bat
  An 18 inch span micro air vehicle with a video camera.
• Micro Lens CCD Camera
  An example of modern "sugar-cube" type CCD camera. Micro-sized video transmitters can be found here.
• Interactive Balloons
  Not exactly "micro-sized", but also very interesting: balloons that can interact conversationally.
• Honey
  Autonomous indoor flying robot for communication and/or interaction between semi-autonomous agents.
• Evolving autonomously hovering mobots
  Excellent paper by Stefan Marti from MIT Media Laboratory.
• FFMP Boomarks
  Very long and interesting list of links accompanying Stefan Marti's paper.
• Keyence
  The home page of some very impressive high-tech hobby products, including RC saucers and helicopters.
• Update of fuzzy helicopter research
  Michio Sugeno of the Tokyo University of Technology has built a helicopter that is eventually supposed to accept 256 verbal commands.
• Micro Air Vehicles - Toward a New Dimension in Flight
  Good introductory paper on Micro Air Vehicles (MAVs) by the Defense Advanced Research Projects Agency (DARPA), focusing on military applications.
• Innovative Mobile Robots
  Development of flying robots at University of Michigan.
• Hummingbird
  Small autonomous helicopter build by a team at the Aerospace Robotics Laboratory, Stanford University.
• BEAR
  Berkeley Aerobot project with the aim to develop an autonomous aerial robot as a testbed of An Integrated Approach to Intelligent Systems - ARO MURI, Intelligent Control Architectures for Unmanned Air Vehicles - ONR , and Software-enabled Control - DARPA.
• Tiny Spies in the Sky
  Excellent article from David Pescovitz, Discovery Channel Online.
• Smart Dust
  Autonomous sensing and communication in a cubic millimeter.