Octopuses are brilliant creatures. Each of its arms includes two-thirds of its neurons, which means each arm has a mind of its own. Octopus arms can open childproof bottles, untie knots, and wrap around prey of any size or shape. Even on rough surfaces under deep-waters, the hundreds of suckers that cover their arms can form strong seals.
Researchers from the Beihang University and the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a robot that mimics an octopus’ arms. The octopus-inspired soft mechanical arm is a flexible, tapered design, complete with suction cups. It can move, grip, and manipulate a wide range of objects. Its suction cups give the gripper a stronger hold on objects of all sizes, shapes, and textures, including eggs, iPhones, and large exercise balls. The research is detailed in Soft Robotics.
August Domel, co-first author of the paper, said:
Most previous research on octopus-inspired robots focused either on mimicking the suction or the movement of the arm, but not both. Our research is the first to quantify the tapering angles of the arms and the combined functions of bending and suction, which allows for a single small gripper to be used for a wide range of objects that would otherwise require the use of multiple grippers.
First, the researchers studied the tapering angle of real octopus arm and calculated which design for grabbing and bending objects would work best for the soft robot. Then, the team observed the layout and structure of the suckers and included them in the design. “We mimicked the general structure and distribution of these suckers for our soft actuators. Although our design is much simpler than its biological counterpart, these vacuum-based biomimetic suckers can attach to almost any object,” said Zhexin Xie, co-first author and Ph.D. student at Beihang University.
Zhexin is also the co-inventor of the Festo Tentacle Gripper. The soft robotic arm is the first fully-integrated implementation of this technology in a commercial prototype.
The team controls the arm with only two valves, one for a vacuum that engages the suckers and another to apply pressure for bending the arm. The tentacle can attach to an object, wrap around it, carry it, and then release it, only by changing the vacuum and pressure.
The device has successfully been tested on a variety of objects such as coffee mugs, thin plastic sheets, eggs, test tubes, and live crabs. The arm was also able to retrieve objects from confined spaces due to its tapering angles.
Katia Bertoldi, a professor at SEAS, and co-senior author of the study said:
The results from our study not only provide new insights into the creation of next-generation soft robotic actuators for gripping a wide range of morphologically diverse objects but also contribute to our understanding of the functional significance of arm taper angle variability across octopus species.
This research was supported in part by Festo Corporate’s project division and the National Science Foundation under grant DMREF-1533985. Other co-authors involved in the study include Zheyuan Gong, Connor Green, Ning An, Tianmiao Wang, Elias M. Knubben, Li Wen, and James C. Weaver.
