Flapping Wings with Micro Sensors and Flexible Framework to Modify the Aerodynamic Forces of a Micro Aerial Vehicle (MAV)

Abstract

The flight of birds or insects has fascinated scholars and physicists for many centuries. Flapping motion, as shown by many nature flyers, is the most efficient way of flying objects whose size are smaller than or around 6 inches. In this chapter, the author introduced how to use modern technology to fabricate the flapping wings for micro aerial vehicles (MAVs) with flexibility and smartness. The terminology of MAV, defined by Defense Advanced Research Projects Agency (DARPA), denotes the size-limitation and the performance requirements of air vehicles (Ashley, 1998). The total wingspan of a MAV is expected to be less than 15 cm; the highest velocity is about 48 km/hr; the range of the flight mission is about 10 km; and the flight endurance is about 20-120 minutes. The earliest flapping vehicle (or ornithopter) was made by Gustave Trouve (Chanute, 1894). No ornithopter was developed using MEMS technology until the end of the last century. A lightest flapping MAV with a total mass of only 11.69 grams was made by Caltech micromachining lab in 1999-2002 (Pornsin-sirirak, 2001; 2002). They used titanium-alloy as the frame of flapping wings, and assigned parylene, a polymer material, as the covering skin of the airfoil. This integrated structure can withstand extreme vibration with frequency of more than 30 Hz and it weights only 0.3 gram. The Caltech MAV, “Micro-bat”, can be remotely controlled as will and the flight endurance is more than 6 minutes. Besides the work of Caltech, several groups in other universities developed their flapping MAVs with different configurations and actuation principles (Website http://www.artificialmuscle. com/), (Website http://fourier.vuse.vanderbilt.edu/cim/projects/crawler.htm), (Website http://www.gtri.gatech.edu/atas/teams/proj_entomopter.html), (Sitti, 2001; Barrett, 2005; Jones, 2005). For instance, TU Delft’s MAV “Delfly” composed of a pair of dragonfly-like flexible wings recently announced their successful hovering (Barrett, 2005). Otherwise, a