Hard lessons for robots at the World Trade Center

Robots that rushed to Ground Zero after the September 11th attacks to locate survivors and victims provided some hard lessons for their developers. In a presentation at the annual AeroSense meeting in Orlando, FL, Scott Pratt of iRobot provided insight as to what urban search and rescue (USAR) robots will need to be successful.

Pratt said the USAR environment is more taxing than military applications because robots operate in "extreme conditions and need wider mobility" to function in close quarters. He noted that some tracked robots at the World Trade Center experienced debris ingestion, limiting their movement. Many robots were simply too big for the extremely small spaces left in the debris pile. Quite often robots would flip over, pointing out the need to either right itself or function in mutiple orientations.

Communications with the robots were a challenge, Pratt added. Using tethers to the robots allowed reliable control and full-frame rate video. But tethers required extra support equipment and created snag points. Wireless links, however, were subject to interference in an environment "awash with RF radiation," he said. And the debris itself attenuated RF signals. Pratt noted that lessons here include using a combination of both types of communications, as well as deploying any tethers from the robot rather than dragging them behind, multiple radio relays, and the greater need for robot autonomy.

Video was the main sensor used on the robots. Operation in 2 to 3 inches of dust at the site highlighted the need for the operators to elevate the camera's point of view, Pratt said. But he noted the operators always wanted to look a little further or go forward a few more feet than they were able. Other lessons, Pratt reported are the usefulness of color imaging to better discern the environment, as well as infrared systems to locate survivors via body heat.

Modular robots, such as a single platform with bolt-on systems, created the most flexibility with the least volume of equipment. Waterproof systems were useful in flooded areas and allowed for vehicle decontamination.

Finally, Pratt added, ease of deployment is vital in getting to a disaster site and setting up quickly to locate survivors. Unfortunately, no one was found by the robots at the World Trade Center, but they were able to find victims that may not have been found using traditional methods.