BATTY RESEARCH
By Jean Thilmany

Someday one of the first acts of a rescuer searching for a missing aircraft or for survivors in a collapsed building may be flinging dozens of robotic bats into the air. The bats would have muscles of wire and flap away silently on wings of titanium alloy and silicon membrane.

Researchers at North Carolina State University in Raleigh, are building tiny, inexpensive robots that would mimic the still-mysterious flight skills of bats. The animals can maneuver inside small, enclosed spaces, slip through dense forest, or spread out in an evenly spaced flock.

If robotic bats can be designed to do that, they could serve to relay cell-phone signals from a lost hiker or to conduct searches over large or tightly enclosed areas, said Stefan Seelecke, an associate professor overseeing the project.

Because bats can fly inside small spaces, researchers at NCSU are working on robots that would mimic bat flight and could be used for rescue missions.s Because bats can fly inside small spaces, researchers at NCSU are working on robots that would mimic bat flight and could be used for rescue missions.

Researchers in the university’s department of mechanical and aerospace engineering have used metal alloys to build several prototypes of the equivalent of a bats’ skeletons. They’ve relied upon a growing body of data about how bats fly.

Since bats can do things like zip into the corner of a room and in three quick strokes be traveling in the opposite direction, they’re a great model for tiny flying machines that must be more maneuverable than, say, tiny airplanes or rotary-wing craft, Seelecke said.

According to Seelecke, the researchers’ idea was to take advantage of the work that nature has already done in designing an elegant approach to flight.

The thin body shells of the cyberbat prototypes and some of the wing bones are made of a lightweight plastic, shaped by a homegrown computer simulation program. The outermost bones are made of a titanium and nickel alloy that the engineers call a shape-memory metal because it provides a full range of natural motion—doing the job of joints, tendons and ligaments—then returns to its original position.

Each muscle that moves a part of the wings, meanwhile, is made of a single strand of so-called smart-metal wire half the diameter of a human hair. When heated, it rearranges its atoms and shrinks rather than expands as metals normally would. That means it can be made to contract like a muscle when it is heated, and then it returns to its previous shape when it cools.

The whole prototype weighs about as much as six paper clips, Seelecke said.

He thinks that if the robot critters work, they could be mass-produced and used in inexpensive flocks.