Researchers at the University of Twente and Radboudumc are developing a new generation of prosthetic technology: a bionic foot that closely replicates the body’s natural walking motion. Within the HealthTech Nexus partnership, they are working on the so-called ’Autonomous leg’, a system designed to support people after a foot amputation in regaining a smooth and effortless gait.
Unlike passive prostheses or devices built on fixed movement rules, the bionic foot uses a neuromechanical model inspired by the spinal cord’s central pattern generators - neural networks that automatically produce rhythmic motions such as walking. "We aim to build a system that functions as naturally and intuitively as possible, without requiring users to consciously control each step," says Prof. Massimo Sartori, Professor of Neuromuscular Robotics & Engineering, University of Twente.
In an initial treadmill study, a test participant walked at different speeds using the bionic prototype. The system rhythmically activated the muscles at the front and back of the lower leg, enabling a more natural walking pattern. According to Ruud Leijendekkers, associate professor and physical therapist at Radboudumc, ’this approach could ultimately reduce fatigue by lowering the cognitive effort traditionally required when using a prosthesis.’
Currently, the model still needs to be connected to an external computer. The next development step involves creating a fully stand-alone, mobile system - including integrated sensors, a compact computer and a long-lasting battery - so testing can move from the lab to real-life environments.
Only when the prosthesis can operate independently will the team be able to evaluate its performance in daily life, such as at home, on the street or in natural terrain. This is an essential step toward certification under the Medical Device Regulation and toward proving its added value over existing prostheses.
The ’Autonomous leg’ is part of the European SimBionics project, conducted in collaboration with Ottobock , Aalborg University (Denmark) and Roessingh Rehabilitation Centre (the Netherlands).
This research is part of HealthTech Nexus , the strategic collaboration between Radboudumc and the University of Twente (TechMed Centre). Together, they focus on addressing unmet healthcare needs: urgent challenges for which no viable solutions currently exist. The researchers leading the ’Autonomous leg’ project are Massimo Sartori, Professor of Neuromuscular Robotics & Engineering, University of Twente, and Ruud Leijendekkers, associate professor and physical therapist at Radboudumc.
For the full background story and a deeper look into the technology, see the complete article " The bionic foot: technology that helps restore a natural step." (Dutch)
