A team of German and Austrian researchers developed a fully biodegradable muscle to be used in robots, according to a study published in Science Advances.
Many researchers believe that robots in the future will be made with artificial muscles to function as living organisms. This approach opens up endless possibilities about what robots can do for us, including assistive wearable devices to help with physical activities and rescue robots used to search for missing people in inaccessible areas.
A team from the Max Planck Institute for Intelligent Systems in Germany and the Johannes Kepler University in Austria believe these robots shouldn’t have a strong environmental impact after use. With this in mind, they designed a fully biodegradable but high-performance muscle using gelatin, oil, and bioplastics. In a Youtube video, the authors explained the technology and showed one possible use as a robotic gripper used in waste collection. Being fully biodegradable means that, at the end of their life, they can be simply put in compost bins.
“We see an urgent need for sustainable materials in the accelerating field of soft robotics. Biodegradable parts could offer a sustainable solution, especially for single-use applications, like medical operations, search-and-rescue missions, and manipulation of hazardous substances. Instead of accumulating in landfills at the end of product life, the robots of the future could become compost for future plant growth,” says Ellen Rumley from the Robotic Materials Department at MPI-IS.
The muscle is an oil-filled pocket partially covered by a pair of electrical electrodes. The high voltage causes opposing charges to build on the electrodes, generating a force between them that forces the oil to move inside the pocket. This movement causes the pocket to contract, just like a real muscle.
The first challenge in this project was to make biodegradable electrodes. After several attempts, the team settled on biopolymer gelatin as the main ingredient. “It was important for us to make electrodes suitable for these high-performance applications, but with readily available components and an accessible fabrication strategy. Since our presented formulation can be easily integrated into various types of electrically driven systems, it serves as a building block for future biodegradable applications,” said David Preninger, co-first author for this project and a scientist at the Soft Matter Physics Division at JKU.
The next step involved finding biodegradable plastics suitable to use with electrical current. The chosen product can withstand 100,000 cycles at several thousand Volts without signs of electrical failure or loss in performance.
The authors believe this is an important shift in robotics. “By showing the outstanding performance of this new materials system, we are giving an incentive for the robotics community to consider biodegradable materials as a viable material option for building robots,” said Rumley. “The fact that we achieved such great results with bio-plastics hopefully also motivates other material scientists to create new materials with optimized electrical performance in mind.”
Rumley EH, Preninger D, Shagan Shomron A, Rothemund P, Hartmann F, Baumgartner M, Kellaris N, Stojanovic A, Yoder Z, Karrer B, Keplinger C, Kaltenbrunner M. Biodegradable electrohydraulic actuators for sustainable soft robots. Sci Adv. 2023 Mar 22;9(12):eadf5551 https://doi.org/10.1126/sciadv.adf5551