WSU e-skin prototype senses pressure and temperature on prosthetics

A prosthetic hand can grasp a coffee cup without knowing whether it is warm, or meet a handshake without reporting the pressure. At Washington State University, graduate student Hongyi Shen and professor Kaiyan Qiu are working on an electronic skin that detects both pressure and temperature at a resolution 10 times finer than current commercial glove sensors, according to the researchers.

The team’s answer to the awkward fit of existing e-skins is a “scan-model-print” process. A prosthetic is scanned, its geometry is used to map the sensing system, and thin layered modules are produced to follow the limb’s freeform curves. The modules combine pressure and temperature sensors, allowing dense measurements across flat and curved surfaces while helping identify surface texture and material properties.

The design also changes how the device is assembled. Instead of adhesives, the modules snap together like interlocking building blocks. Washington State researchers used 3D printing and laser cutting, a manufacturing route Kaiyan Qiu described as relatively simple, low-cost and convenient to scale. The system is intended to address problems that have limited existing electronic skins: high cost, small coverage areas, poor fit and large volumes of data that can hinder real-time operation.

The sensing layer is not yet a complete artificial sense of touch. The Washington State team has filed an invention disclosure for a provisional patent and is developing an actuator that would convert sensor readings into stimulation signals for nearby nerves. That missing step is what could allow an amputee to receive information about what the prosthetic hand is touching.

So what changes, concretely? A personalized prosthetic could eventually provide finer information about grip, texture and warmth without requiring a sensor surface designed only for a flat shape. For now, the demonstrated advance is the customizable sensing system itself; nerve stimulation, clinical use and wider adoption remain future stages. The research was led from Washington State’s School of Mechanical and Materials Engineering and published in Cell Reports Physical Science.