Building a Robotic Octopus

August 3, 2009

A soft-bodied robot isn't as easy to build as some might think, but it offers many advantages over the stiff robotic arms now being used, says Professor Binyamin Hochner at Hebrew University of Jerusalem. The Israeli role in the project is developing the mechanics of octopus locomotion. “We are analyzing octopus behavior and motor control strategies for the arm, which have multiple degrees of freedom,” says Hochner.

When complete, the scientists are expected to have built a life-like octopus robot, with a head, body, and eight tentacles, which can each bend in 360 degrees. Elongating and stretching like the real ones do, the scientists' robotic tentacles will be able to stretch out and become thin in order to hold small objects in small spaces. The researchers intend to mimic the exact same structure and properties of a real octopus. Sucker systems, a nervous system, the sensory system, and even the structure of the skin will be copied, Hochner says. “We are replicating the muscular structure of an octopus by making a robot with no rigid structure—and that is completely new to robotics,” said one of Hochner's partners from Italy.

Octopus tentacles are made up of four longitudinal muscles, and the scientists plan on replicating them with a soft silicone rubber fitted with an electroactive polymer called a dielectric elastomer. When they apply an electric field to this polymer, it will squeeze the silicon, making it shorter, and thereby mimic the contraction process in octopus and other soft-bodied marine animals. So far, scientists have only been able to develop a snake-like tentacle that inflates with compressed air. Due to buoyancy issues, such a device would never work underwater. For more information: www.octopus.huji.ac.il; 972-2-658-5080; tamnun@lobster.Is.huji.ac.il

Excerpts from an article by Karin Kloosterman, www.israel21c.org

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