Before each experimental run in a test chamber filled with quarter-inch-diameter plastic spheres, the researchers submerged the robot a couple inches into the granular medium and leveled the surface. Then they tracked the robot's position until it reached the end of the container or swam to the surface.
The researchers investigated the vertical movement of the robot when its head was placed at five different degrees of inclination. They found that when the sandfish-inspired head with a leading edge that formed an angle of 155 degrees with the horizontal plane was set flat, negative lift force was generated and the robot moved downward into the media. As the tip of the head was raised from zero to 7 degrees relative to the horizontal, the lift force increased until it became zero. At inclines above 7 degrees, the robot rose out of the medium.
"The ability to control the vertical position of the robot by modulating its head inclination opens up avenues for further research into developing robots more capable of maneuvering in complex environments, like debris-filled areas produced by an earthquake or landslide," noted Goldman.
The robotics results matched the research team's findings from physics experiments and computational models designed to explore how head shape affects lift in granular media.
"While the lift forces of objects in air, such as airplanes, are well understood, our investigations into the lift forces of objects in granular media are som
|Contact: Abby Robinson|
Georgia Institute of Technology Research News