Photo credit: Tommaso Ranzani
The arm serves a dual function. One part manipulates organs while the other operates. According to researchers from the Sant'Anna School of Advanced Studies in Italy, the device could potentially reduce the number of instruments used in surgery.
“The human body represents a highly challenging and non-structured environment, where the capabilities of the octopus can provide several advantages with respect to traditional surgical tools,” said the study’s lead author, Dr. Tommaso Ranzani. “Generally, the octopus has no rigid structures and can thus adapt the shape of its body to its environment. Taking advantage of the lack of rigid skeletal support, the eight highly flexible and long arms can twist, change their length or bend in any direction at any point along the arm.”
Recreating the flexibility of the octopus
In order to recreate the flexibility of an octopus, the team engineered two interconnecting identical modules. Each one can move thanks to three cylindrical chambers that are evenly spaced within the module. Altering and combining the inflation of these chambers allows the module to bend and stretch in different directions.
The engineers filled a flexible membrane with a granular media and used a “granular jamming phenomenon” to control the stiffness of the two modules. The membrane’s density increases when a vacuum is applied to it, making the membrane rigid.
During tests, the group concluded that their device could bend to angles of up to 255° and stretch to more than 60 percent of its length. Through the stiffness mechanism, the device can go from 60 percent stiffness to up to 200 percent. The team also successfully tested the robotic arm in a simulated surgery using balloons filled with water.
“Traditional surgical tasks often require the use of multiple specialized instruments such as graspers, retractors, vision systems and dissectors to carry out a single procedure,” Ranzani said. “We believe our device is the first step to creating an instrument that is able to perform all of these tasks, as well as reach remote areas of the body and safely support organs around the target site,” he added.
A detailed account of the team’s research was recently published in the journal Bioinspiration and Biomimetics. For more information, visit IOP Publishing’s website.