Researchers from the Sant'Anna School of Advanced Studies have created a robotic arm that bends, stretches and squeezes through cluttered environments, taking inspiration from the tentacles of an octopus.
The device was developed as a surgical tool, giving surgeons easy access to hard-to-reach parts of the body and letting them manipulate soft organs once there without damaging them. The researchers believe that it can reduce the number of tools used during surgery, limiting as well the entry incisions since one part of the arm operates while another handles organs.
Presented in the journal Bioinspiration and Biomimetics, the device features a key advantage against traditional instruments because it can quickly and easily transform from being a flexible tool into a rigid instrument, a characteristic it adopted from octopus arms.
To harness this, researchers came up with a construction that featured two interconnecting identical modules, each of which moves by being inflated. Every module has three cylindrical chambers evenly spaced inside. By combining and alternating inflation in the chambers, the researchers made it possible for the module to stretch and bend in different directions.
A granular jamming phenomenon is exploited to impart stiffness to the modules, filling a flexible mebrane within the module with granular media. When the membrane is vacuumed, the density increases, making it rigid.
Dr. Tommaso Ranzani, lead author of the study, said the body represents a challenging environment where abilities mimicked from an octopus can offer several advantages. A series of characterization tests were carried out on the device, resulting in an ability to bend at 255-degree angles and stretch at up to 62 percent of its length, and also increase rigidity levels from 60 percent to 200 percent.
The device's ability to manipulate organs during surgical tasks were tested using water-filled balloons to simulate the fragility of organs in the body. In the scenarios simulated by researchers, the device successfully showed it is capable of handling organs with extreme care.
"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," said Ranzani.
The study "A bioinspired soft manipulator for minimally invasive surgery" was supported by the European Communities Seventh Framework Program through the STIFF-FLOP project grant. A. Menciassi, M. Cianchetti and G. Gerboni also contributed to the work.
Photo: Albert Kok | Wikimedia Commons
