An international project has developed stable and efficient artificial robot muscles based on new material combinations.
An international cooperation between the Johannes Kepler University Linz, the Scuola Superiore Sant’Anna di Pisa and the University of Trento combines technological progress with ecological sustainability.
The joint project resulted in a groundbreaking method for the development of novel soft actuators and artificial robot muscles with improved performance and significantly reduced energy consumption. Leading this work were Prof. Martin Kaltenbrunner (Department of Soft Matter Physics at the JKU) and Marco Fontana , Professor at the Institute of Mechanical Intelligence at the Scuola Superiore Sant’Anna di Pisa. Their innovative results, which have led to the development of this new method for creating more stable and efficient artificial muscles, have now been published in the renowned journal Nature Electronics.
Previous electric motors too bulky
Actuators that convert electrical energy into movement or force play a central role in our daily lives, even if they often go unnoticed. Until now, electric motors have mainly been used, which work well but are made of metal. They are therefore bulky and heavy. A new generation of actuators based on soft materials such as polymer films, on the other hand, offers unique properties such as low weight, high power per weight, silent operation and even biodegradability.
"We use multi-material structures for this," explains Prof. Martin Kaltenbrunner. "These are essentially ’pockets’ made of flexible plastic films filled with oils and coated with electrodes. When a voltage is applied, the films displace the liquid and the pocket contracts, similar to the way a biological muscle moves."
This system can be used to build artificial muscles for robots, adjustable lenses or tactile surfaces. However, by applying a constant voltage, only short-term muscle contractions are possible, which is a significant limitation for practical applications. Together with JKU researchers, Ion-Dan Sīrbu from the Scuola Superiore Sant’Anna di Pisa was able to change this during a research stay at the JKU.
JKU technology as a starting point
We experimented with a plastic film that JKU physicist David Preninger used for his work on biodegradable artificial muscles. We found a material that can maintain a constant force over any length of time. We realized that we had made a significant discovery," says Sīrbu.
Since then, the team has worked on a theoretical model and carried out in-depth material characterizations. "The beauty of our model is its simplicity and that it is not limited to existing actuators. We believe that our results will provide the scientific community with a simple but powerful tool for the design and investigation of new systems," describes David Preninger, co-first author of the study and PhD student at the JKU’s Department of Soft Matter Physics.
Enormous energy savings
Institute Director Martin Kaltenbrunner confirms the significance of the discovery: "The interesting thing is that we have not only made this technology much easier to use. Our results can also be used to find material combinations that reduce energy consumption by a factor of a thousand."
Using the identified material combinations, the scientists have already successfully produced and operated various types of artificial muscles, adjustable lenses and tactile displays. Prof. Fontana emphasizes: "Understanding the basic mechanisms of soft actuators, as identified in this study, has the potential to bring about a significant leap in the field of assistive devices, automatic machines and mobile robots for Earth, ocean and space exploration."
The project thus makes a significant contribution to the search for cost-effective, high-performance solutions in robotics, which should also ensure low consumption and a low environmental impact in terms of sustainability.
