Researchers from North Carolina State University created a soft, flexible sensor system from electrically conductive yarns. This prototype could help prosthetists map pressure points within the prosthetic socket. This study is published online in the IEEE Sensors Journal.
According to Jordan Tabor, the study's first author, people typically use rigid sensors to measure their prosthetic limbs' pressure points. However, these sensors are bulky and heavy, which means prosthetic users can't comfortably use the sensors daily as it also negatively affects the fit of their prosthetic limb.
In contrast, the textile sensor patch prototype is lightweight and soft. It features a lattice of conductive yarns connected to a tiny computer. To verify its effectiveness, the researchers tested the system on a prosthetic limb in walking experiments with two volunteers. They soon found out that the prototype could reliably track pressure changes in real-time.
The study was a collaboration between researchers from various areas of expertise: computer, biomedical, electrical, and textile engineering at NC State. Meanwhile, rehabilitation engineering researchers performed the human experiments.
The design process
The collaboration's goal is to design a lightweight sensor system that is small enough for human use. The researchers stitched the yarns into a lattice to create an electromagnetic field to arrive at the current prototype. When a bit of electrical power through a small battery was applied, the researchers observed they could measure the electrical charge amount by pulling the yarns together at each lattice point.
The charges varied depending on the yarns' proximity, mimicking their placements when the user applies pressure. Then the researchers connected, insulated, and laid the yarns on a textile fabric before joining it to a piece of small electronic equipment to capture the data. They included a tiny radio to track the measurements wirelessly.
Although the researchers used commercially available yarn for the study, they are currently developing a textile to identify more than just load changes in a prosthetic socket.
The project's next step is to combine the sensors into a prosthetic socket or another wearable item. The researchers would also need to investigate the sensor's clinical value in a more extensive study.
According to Helen Huang, a senior co-author of the study and a rehabilitation engineer, the study's larger vision is to design a wearable, like a prosthetic sock, or to integrate the sensor system into a prosthetic socket. This will allow the prosthetic user to monitor in real-time what's happening in their prosthetic limb in terms of weight distribution and other necessary measurements.What do you think of this prosthetic development? If made commercially available, will you use the sensor patch?