Recently, a team of researchers at the Wyss Institute for Biologically Inspired Engineering and the John A. Paulson School of Engineering and Applied Sciences (SEAS) at Harvard University created a flexible, soft, capacitive sensor. Constructed of silicone and fabric to simultaneously move with the body and detect movement, it’s being integrated with fabric to make robotic apparel.
The research was published in Advanced Materials Technologies, and the protocol is available as part of the Harvard Biodesign Lab's Soft Robotics Toolkit.
The technology consists of a thin sheet of silicone placed between two layers of silver-plated, conductive fabric. By pulling from the ends, the silicone layer gets thinner and the conductive fabric layers get closer together. These structural modifications create changes in stored electrical charge, which is what forms the sensor and makes it capable of tracking movement.
The interlocking fabric fibers help limit the extent to which the silicone deforms while stretching, and the silicone helps the fabric return to its original shape. Flexible wires are attached to the conductive fabric in allowing electrical information to be transmitted to a circuit, but without the use of a bulky interface. Additionally, embedding the silicone in conductive fabric creates a matrix that improves sensitivity and responsiveness.
Along with creating a flexible sensor that can essentially be woven into textile materials, the team designed a batch-manufacturing process that allows for quicker customization. By attaching the fabric to both sides of the silicone core, the silicone can fill some of the air gaps in the fabric, mechanically locking it to the silicone and increasing the surface area. This translates to an ability to store more electrical charge in providing quicker responses.
Like a lot of IoT-inspired research, the combination of flexible materials and electrical sensors means data can be acquired more quickly, and from more new sources with little or no regard to physical proximity. Early applications could include apparel for tracking athletes and medical patients, with the long-term benefits focused on preventing injuries and reducing medical expenses.
Looking further out, using this type of robotic gear could make next-generation exoskeletons a reality for pilots, astronauts, police officers, and soldiers. The combination of remote monitoring technologies and extensive data acquisition is already being realized on the mechanical level. These types of developments in the wearables arena will expand information visibility, and truly optimize the combined potential of mechanical systems, as well as the people utilizing them.