A research team in Korea developed a new type of sensor technology that will allow people better control of robotic prosthetic legs. The research, led by Sang-hoon Lee, PhD, at the Daegu Gyeongbuk Institute of Science and Technology’s Department of Robotics and Mechatronics Engineering, expects the sensor—called an imperceptive surface EMG (sEMG)—to contribute to rehabilitation and a better quality of life.
Because of the challenges of traditional sEMGs for prosthetic control, including pressure, narrow space, and perspiration negatively affecting sensor performance, the research team developed the imperceptive sEMG sensor, a biointerface formed through a microelectromechanical system. The imperceptive sEMG sensor mimics a serpentine structure to provide flexibility and elasticity while achieving breathability and adhesion, so it can be applied to various parts of the body and used repeatedly over an extended period of time. Furthermore, combined with a wireless module, the sensor obtains real-time signals generated when amputees walk with robotic prosthetic limbs, sockets, and silicone liners.
To verify the sensor’s function, the research team attached the imperceptive sEMG sensor to a participant’s residual limb and evaluated the sensor’s function by recording the participant’s muscle signals. The results demonstrated that the sensor successfully acquired high-quality real-time muscle signals as the person walked in various environments (on flat ground, up and down slopes, and on stairs) and transmitted the signals wirelessly to assist in walking, as verified from the motion analysis sensor embedded in the robotic prosthetic leg.
Furthermore, by analyzing muscle signals generated from plantarflexion and dorsiflexion, the research team confirmed that the selective signal acquisition performance of the imperceptive sEMG sensor is better than that of other commercial sensors.
“Although there are more amputees than we think in Korea and around the world, there are many restrictions on daily activities and living because prosthetic legs that can be controlled as the wearer intends are not available. Based on the results of this research, we will continue to further research and develop bionic limbs which can implement sensory and motor functions, just like that of human limbs, to help amputees enjoy all activities of daily living.”
Editor’s note: This story was adapted from materials provided by Daegu Gyeongbuk Institute of Science and Technology (DGIST).
The open-access study, “Imperceptive and reusable dermal surface EMG for lower extremity neuro-prosthetic control and clinical assessment,” was published in npj Flexible Electronics.
Caption/Credit: Schematic illustration of the flexible and stretchable sEMG sensors. Image courtesy of npj Flexible Electronics (2023).
