A Cleverly-Tapered Tentacle Brings Octopus-Inspired Grasping Abilities to Soft Robotics

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and Beihang University have developed a soft robotic arm capable of gripping, moving, and manipulating objects — but with an octopus-like tentacle, rather than traditional grippers.

"Most previous research on octopus-inspired robots focused either on mimicking the suction or the movement of the arm, but not both," claims Dr. August Domel, co-first author of the paper describing the new robot arm. "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."

The impressively-realistic tentacle is built to a precise tapering angle mimicking that of a real-world octopus, while the suckers have a specific layout and structure which makes them better suited to gripping than most.

"We mimicked the general structure and distribution of these suckers for our soft actuators," adds co-first author Zhexin Xie. "Although our design is much simpler than its biological counterpart, these vacuum-based biomimetic suckers can attach to almost any object."

The arm is controlled via two valves: Changing the pressure via one enables the arm to bend and curl around a target object; pulling a vacuum through the other engages the suckers and allows them to grip. The design has been proven effective on a range of real-world objects from plastic sheets and coffee mugs to test tubes and eggs — and, in honor of the design's biological origins, even a living crab.

"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," concludes co-senior author Professor Katia Bertoldi, "but also contribute to our understanding of the functional significance of arm taper angle variability across octopus species."

The team's work has been published under closed-access terms in the journal Soft Robotics; Xie, meanwhile, is co-inventor of the Festo Tentacle Gripper, the first prototype designed to bring the design to market as a commercial product.