Researchers restore a sense of touch to prosthetic hands

Restoring a sense of touch to prosthetic hands is looking promising thanks to liquid metal sensors developed by researchers from Florida Atlantic University’s College of Engineering and Computer Science, as well as collaborators in the United States.

The technology, encapsulated within silicone-based elastomers, is claimed to provide advantages over traditional sensors, including high compliance, conductivity, stretch ability and flexibility.

Researchers used individual fingertips on the prosthesis to differentiate between various speeds of a sliding motion along various textured surfaces, during the study, which is detailed in Sensors.

To detect speeds and textures, researchers trained four machine learning algorithms. Twenty trials were collected, for each of the ten surfaces, to test the ability of the machine learning algorithms to differentiate between the ten various complex surfaces comprised of randomly generated permutations of four separate textures.

The integration of tactile information from liquid metal sensors on four prosthetic hand fingertips discriminated between complicated, multi-textured surfaces, according to the findings. The machine learning algorithms were able to discern between all of the speeds with each finger with pinpoint accuracy. This new technology could help amputees regain their sense of touch by improving the control of prosthetic hands and providing haptic feedback.

Senior author, a member of the FAU Stiles-Nicholson Brain Institute and the FAU Institute for Sensing and Embedded Network Systems Engineering (I-SENSE) and an associate professor in the Department of Ocean and Mechanical Engineering, Erik Engeberg, Ph.D, stated: “Significant research has been done on tactile sensors for artificial hands, but there is still a need for advances in lightweight, low-cost, robust multimodal tactile sensors. The tactile information from all the individual fingertips in our study provided the foundation for a higher hand-level of perception enabling the distinction between ten complex, multi-textured surfaces that would not have been possible using purely local information from an individual fingertip. We believe that these tactile details could be useful in the future to afford a more realistic experience for prosthetic hand users through an advanced haptic display, which could enrich the amputee-prosthesis interface and prevent amputees from abandoning their prosthetic hand.”