The intelligent flying eye

Abstract

Search-and-rescue operations can be very difficult. Consider as a typical scenario a partially collapsed building that may contain trapped survivors. But those people are surrounded by debris that presents a formidable obstacle to searchers. How do you find the survivors, and how do you get them out safely? The most important task in such a situation is to narrow down the search area and guide the rescue workers to the right location. The rescuers also need to know the inner state of the building to assess the damage, anticipate likely risks, and determine the best rescue strategy. Any ground-based robotic device that is sent into the damaged area to obtain this information will very likely get entangled in rubble. So what are the alternatives? What if you could send in a tiny helicopter, a micro air vehicle (MAV), to do the job? A MAV benefits from its vertical degree of freedom: it can evade obstacles on floors by changing altitude, and it can use vertical spaces, such as elevator shafts, to quickly access the most badly damaged levels. Within minutes, it can bring back video images of the wrecked interior. In addition to showing the locations of survivors, the images can help civil engineers assess the stability of the structure to help protect both rescue workers and the victims they are trying to save. The PIXHAWK Cheetah MAV (see Figure 1) is such a device. With onboard intelligence and autonomous-navigation capabilities, the Cheetah can be an extremely useful tool for rescue missions in hazardous environments. This four-rotor MAV is 55cm in diameter, measured across its rotor blades. Powered by lithium polymer batteries, the Cheetah can fly for up to 12 minutes. It features four cameras with flexible mountings and an onboard image-processing computer (see Figure 2). The Cheetah’s computer-vision system enables it to assess and solve navigational problems with no outside help. Some robotic devices send back images by means of wireless communication. Current MAV designs use wireless image transmission and offboard processing1, 2 or global-positioning systems (GPS) for controlling the vehicle.3 A wireless-transmission Figure 1. Operational model of the PIXHAWK Cheetah.