Autonomous planes are nice, but if you need low-altitude agility and hovering, especially in urban areas, nothing beats a robo-chopper. Several groups are developing them, but the Aerobot Project at the University of California, Berkeley, is a leader in key areas like autonomous obstacle-avoidance and coordination between helicopters. Although the group has made strides in computer vision and other forms of sensing, and in navigation and control software, practical machines are still several years away.

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