Electric Stimulation Gives Robot-Assistive Surgery a Sense of Touch

A team of researchers at Texas A&M have performed studies evaluating how electrical stimulation can help users control robots, for example helping surgeons steady their movements during robot-assisted procedures.

They found, in 11 subjects, that small electrical stimulations to the fingertips can help users control the pinching of a hardwood block with a robotic arm. These findings can one day help stabilize and improve control of surgical robots.

In many surgical robots, visual feedback is the only type of feedback surgeons have of their movements; it is hard to know how close the instruments are to each and tissues being operated on. This makes it difficult to control force and movements accurately in the operating environment. To address this challenge, the researchers developed an electrical-stimulating glove and system for providing feedback to users controlling a robotic arm.

The user wears a glove, which controls a robotic claw based on the wearer’s movements. The subject is asked to control the robotic claw to gently press both sides of a hardwood block for 5 seconds, as lightly as possible. The glove is designed to give mild electrical stimulation to the fingertips of the wearer, with increasing frequency as the wearer gets closer to touching the surface of the block. Pressing force was measured using sensors attached to the block. Using the new technology, users were able to achieve a much lighter touch than without.

“Surgeons can only know how far apart their actual fingers are from each other indirectly, that is, by looking at where their robotic fingers are relative to each other on a monitor,” said Prof. Hangue Park, the senior author of the study published in journal Scientific Reports. “This roundabout view diminishes their sense of how far apart their actual fingers are from each other, which then affects how they control their robotic fingers.”

“Our goal was to come up with a solution that would improve the accuracy in proximity estimation without increasing the burden of active thinking needed for this task,” he added. “When our technique is ready for use in surgical settings, physicians will be able to intuitively know how far their robotic fingers are from underlying structures, which means that they can keep their active focus on optimizing the surgical outcome of their patients.”