The JKU strengthens robots with artificial muscles

For several years now, researchers in Linz have been developing components that convert electrical signals into movements – so-called actuators. In the specialist magazine “Nature Electronics”, the group and colleagues from Italy are now presenting a further development: “artificial muscles” that can theoretically maintain their strength indefinitely. This opens up new possibilities for replacing electric motors in devices, for example.

Martin Kaltenbrunner and his team from the Soft Matter Physics Department and the “LIT Soft Materials Lab” at the JKU have been able to come up with amazing developments in moving machines and robots based on soft materials in recent years. These include systems that can be described as “artificial muscles”.

Now these have been further developed: The “electrostatic actuators” are essentially bags made of plastic films and filled with oil. Electrodes are attached to the outside. If you then apply tension, the foils attract each other and displace the oil. This creates a movement similar to that which a muscle performs when tensing.

The problem so far has been that these robot muscles could not maintain strength over a long period of time. In the present work, the scientists explain theoretically what happens physically between the attracting films and provide experimental implementations. Better models allowed the researchers to more accurately predict how the material would behave under tension.

This brought solutions to the problem of loss of strength: In a video accompanying the study, the researchers illustrate this with mechanical arms that lift a 10-gram weight. Construction with traditional materials cannot hold the load continuously, while a biopolyester actuator will endure.

Basis for new discoveries

JKU physicist David Preninger is convinced that new materials with the desired properties could be found based on the theoretical work. Significantly more energy-saving material combinations are also possible. A key advantage of the now improved actuators is that they are very light and therefore efficient compared to the electromagnetic motors currently widely used.