Touch Transforms Perception: Bionic Hand Senses and Grasps Like a Human

Johns Hopkins University engineers have created a groundbreaking prosthetic hand that can delicately grip plush toys, securely hold water bottles, and handle other everyday objects with human-like precision. By carefully adjusting its grasp, the hand prevents damage or mishandling, offering a practical solution for individuals with hand loss while also advancing robotic interaction with the environment.

Unlike traditional robotic hands, which tend to be either too rigid or too soft, this hybrid design balances flexibility and strength, enabling more natural movement and touch sensitivity. The research, published in Science Advances, introduces an innovative system that mimics the physical and sensory functions of a human hand.

“Our goal from the start was to create a prosthetic that closely replicates the human hand in both function and feel,” explained Sriramana Sankar, the biomedical engineer leading the project. “We want individuals with upper-limb loss to interact freely with their surroundings, safely hold their loved ones, and regain confidence in daily tasks.”

Developed by the same research team that introduced the world’s first electronic “skin” with a human-like sense of pain in 2018, the prosthetic incorporates a multi-finger system made of rubber-like polymers and a rigid 3D-printed internal skeleton. Inspired by the layers of human skin, it features three layers of tactile sensors, allowing it to detect different shapes and surface textures rather than just basic touch.

Smart Prosthetics: AI-Powered Touch Brings Realistic Sensation

Each soft, air-filled finger joint responds to muscle signals from the forearm, while machine-learning algorithms process sensory feedback to create a lifelike sense of touch. “The system translates signals from the artificial touch receptors into nerve-like messages, delivering natural sensory feedback through electrical nerve stimulation,” Sankar added.

In laboratory tests, the prosthetic hand successfully identified and manipulated 15 different objects, ranging from soft stuffed animals and delicate dish sponges to sturdy pineapples and metal water bottles. It outperformed existing alternatives with a 99.69% success rate, dynamically adjusting its grip to prevent slipping or crushing fragile items. One of its most impressive feats was picking up a thin plastic cup filled with water using only three fingers—without denting or spilling it.

“The human hand isn’t entirely rigid or purely soft—it’s a hybrid system with bones, soft joints, and tissue working together,” Sankar said. “That’s exactly what we aimed to replicate. This is uncharted territory for robotics and prosthetics, which have not fully embraced hybrid technology before.”

Restoring Touch: The Three Key Components of Next-Generation Prosthetic Hands

To restore a sense of touch for amputees, prosthetic hands must integrate three critical components: sensors to detect environmental feedback, a system to convert that data into nerve-like signals, and a method to stimulate nerves so the user can perceive sensations. Nitish Thakor, a Johns Hopkins biomedical engineering professor who directed the research, emphasized how the bioinspired design accomplishes this by using muscle signals from the forearm to control grip strength and movement.

“Our system mimics how the human nervous system works,” Thakor explained. “If you’re holding a cup of coffee, your fingertips and palm sense when it starts slipping, sending signals to your brain. This prosthetic uses similar principles—its touch receptors produce nerve-like messages so the robotic hand ‘knows’ what it’s touching and reacts accordingly.”

While this breakthrough in hybrid robotics could transform both prosthetic technology and robotic applications, further refinements are still needed. Future enhancements may include stronger grip forces, additional sensors, and industrial-grade materials.

“This level of dexterity isn’t just critical for next-generation prosthetics,” Thakor noted. “Future robotic hands must handle both delicate objects like glass or fabric and heavier, more durable materials. By combining soft and rigid elements—just like human skin, tissue, and bones—this hybrid approach paves the way for more advanced, human-like robotics.”

Read Original Article: TechXplore

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