The advance in robotics has boosted the application of autonomous
vehicles to perform tedious and risky tasks or to be cost-effective
substitutes for their - man counterparts. Based on their working
environment, a rough classi cation of the autonomous vehicles would
include unmanned aerial vehicles (UAVs), - manned ground vehicles
(UGVs), autonomous underwater vehicles (AUVs), and autonomous surface
vehicles (ASVs). UAVs, UGVs, AUVs, and ASVs are called UVs (unmanned
vehicles) nowadays. In recent decades, the development of - manned
autonomous vehicles have been of great interest, and different kinds of
autonomous vehicles have been studied and developed all over the world.
In part- ular, UAVs have many applications in emergency situations;
humans often cannot come close to a dangerous natural disaster such as
an earthquake, a ood, an active volcano, or a nuclear disaster. Since
the development of the rst UAVs, research efforts have been focused on
military applications. Recently, however, demand has arisen for UAVs
such as aero-robotsand ying robotsthat can be used in emergency
situations and in industrial applications. Among the wide variety of
UAVs that have been developed, small-scale HUAVs (helicopter-based UAVs)
have the ability to take off and land vertically as well as the ability
to cruise in ight, but their most importantcapability is hovering.
Hoveringat a point enables us to make more eff- tive observations of a
target. Furthermore, small-scale HUAVs offer the advantages of low cost
and easy operation.
