The loss of a limb is always the consequence of a painful event. Beyond the permanent physical impairment, amputation generates a profound psychological trauma. When the Italian Institute of Technology and INAIL asked 21AM to design an ankle and knee prosthetic system, we started from a fundamental question: how can design support recovery and facilitate the acceptance of a prosthetic limb?
To answer this, 21AM developed a research-driven process with the Rehab Technologies Lab at the Italian Institute of Technology, integrating robotics, cognitive ergonomics, and cognitive psychology. Through user observation, expert interviews, and cognitive analysis tools, we investigated how prosthetic devices are perceived and how aesthetics can influence trust, self-image, and emotional acceptance. A key insight came from Professor Masahiro Mori's "uncanny valley" theory, which became a guiding principle throughout the project.
The result is UNICO (knee) and ARMONICO (ankle), a clinically tested robotic lower-limb prosthetic system currently at TRL7 stage. Research findings directly shaped the design, leading to a balance between anatomically credible volumes and deliberately artificial elements. Rather than replicating the human body, the prostheses express a visual language that supports psychological acceptance while clearly communicating their technological nature.
Both devices feature a hybrid system that allows users to switch modes according to their needs, including a dedicated driving mode activated through a button on the knee. Working together, UNICO and ARMONICO enhance mobility and coordinate movement across walking and stair-climbing scenarios. ARMONICO also incorporates an innovative waterproof inverted joint that hermetically seals the shell. UNICO prototype secured first place in the Leg Prosthesis category at Cybathlon 2024 in Switzerland.