Reviewed by Lexie CornerMar 7 2025
Scientists at the Max Planck Institute for Intelligent Systems, the University of Tübingen, and the University of Stuttgart, under the Bionic Intelligence Tübingen Stuttgart (BITS) collaboration, developed a biorobotic arm that can mirror human tremors, such as those caused by Parkinson's disease. The arm uses artificial muscles to suppress involuntary shaking, offering a potential solution for tremor patients to better manage daily tasks.
From left to right: Alona Shagan Shomron, Syn Schmitt, Christoph Keplinger and Daniel Häufle. Image Credit: MPI-IS / W. Scheible
It is estimated that over 80 million people globally experience tremors, such as those seen in individuals with Parkinson’s disease. Involuntary, periodic movements can significantly impact a patient’s ability to perform daily tasks, like drinking from a glass or writing. Wearable soft robotic devices may offer a solution for suppressing these tremors, but current prototypes are not yet sufficiently advanced to provide a viable option.
The scientists equipped a biorobotic arm with two strands of artificial muscles attached to the forearm. The biorobotic arm, referred to as the "mechanical patient," simulates a tremor. Real tremors were recorded and projected onto the arm to replicate how each patient shakes their wrist and hand.
When tremor suppression is activated, the lightweight artificial muscles, made of electro-hydraulic actuators, contract and relax to compensate for the back-and-forth movement. As a result, the tremor is nearly undetectable.
The team aims to achieve two objectives with this biorobotic arm. First, they intend to use it as a platform for other researchers to test new concepts in assistive exoskeleton technology. Developers can evaluate the performance of soft artificial muscles through biomechanical computer simulations, avoiding the need for time-consuming and expensive clinical trials, which are even restricted in some countries.
In addition, the arm serves as a testing ground for the artificial muscles developed by the Robotic Materials Department at MPI-IS. Known as HASELs, these muscles have been refined over the years. The team’s goal is for HASELs to eventually form the basis of a wearable device that tremor patients can comfortably wear to assist with everyday tasks, such as holding a cup.
We see a great potential for our muscles to become the building blocks of a garment one can wear very discreetly so that others don't even realize the person suffers from a tremor. We showed that our artificial muscles, which are based on the HASEL technology, are fast and strong enough for a large range of tremors in the wrist. This shows the great potential of a HASEL-based wearable assistive device for individuals living with a tremor.
Alona Shagan Shomron, Study First Author and Postdoctoral Researcher, Robotic Materials Department, Max Planck Institute for Intelligent Systems
“With the combination of mechanical patient and biomechanical model, we can measure if any tested artificial muscles are good enough to suppress all tremors, even very strong ones. So if we ever created a wearable device, we could adjust it to respond individually to each tremor,” Daniel Häufle added.
He is a professor at Tübingen University’s Hertie Institute for Clinical Brain Research. Among other things, he created the computer simulation and collected the tremor data from patients.
The mechanical patient allows us to test the potential of new technologies very early in the development, without the need for expensive and time-consuming clinical testing on real patients. A lot of good ideas are often not further pursued, as clinical testing is expensive and time-consuming, and hard to fund at very early stages of technology development. Our mechanical patient is the solution, which allows us to test the potential very early in the development.
Syn Schmitt, Professor, Computational Biophysics and Biorobotics, University of Stuttgart
“Robotics has great potential for healthcare applications. This successful project highlights the key role that soft robotic systems, based on flexible and deformable materials, will play," Christoph Keplinger, the Director of the Robotic Materials Department at MPI-IS, concluded.
Journal Reference:
Shomron, A. S. et. al. (2025) A robotic and virtual testing platform highlighting the promise of soft wearable actuators for wrist tremor suppression. Device. doi.org/10.1016/j.device.2025.100719