“Although nature does not necessarily provide the optimal form, it still outperforms many artificial systems and offers valuable insights for designing functional machines based on elegant principles,” says Josie Hughes, head of EPFL’s Computational Robot Design and Fabrication Lab. That ethos finds memorable expression in a stunning proof-of-concept: discarded langoustine shells repurposed as robotics components that lift, grip, and swim.
The engineering challenge was to take advantage of the lobster tail’s unique architecture-six articulated segments combining mineralized rigid plates with flexible joint membranes-without removing the mechanical advantages developed through evolution. In order to introduce restoring force, the EPFL team inserted a soft elastomer along the dorsal side, and threaded inextensible tendons through ventral segments serving as natural pulleys. In addition, they mounted the structure on compact motorized bases. A silicone coating, in variants tested such as Ecoflex and Dragon Skin, lengthened operational life from less than five hours to as many as 39 hours by preventing membrane dehydration and stiffening.
Performance metrics were compelling. A single three‑gram exoskeleton segment supported payloads up to 680 grams in specific configurations. Paired grippers adapted passively to diverse geometries, from pens to tomatoes, by virtue of their underactuated continuum mechanics. As swimming fins, the shells propelled a small robot at 11 cm/s in pool trials, with symmetric power and return strokes outperforming asymmetric patterns due to full fin deployment dynamics. This biohybrid design provides for directional stiffness spikes-up to 3.3 N·mm per degree-when plates lock at extension limits, thereby allowing for thrust generation akin to a ratchet in resistive media.
This design inherently carries the dimension of sustainability: most of the synthetic components-motors, elastomers, and tendons-come cleanly off for reuse. Biological shells are biodegradable, in line with circular economy principles; such aspects are few and far between in robotics. “By repurposing food waste, we propose a sustainable cyclic design process in which materials can be recycled and adapted for new tasks,” says Hughes. This sidesteps both the logistical and ethical challenges of live‑tissue biohybrids-think jellyfish systems which require nutrient supply and temperature control-and retains the mechanical sophistication of natural structures.
The idea fits within larger-scale developments in biodegradable or bio-derived materials for robotics. Chitin, the polysaccharide that gives the framework of crustacean shells, is already a candidate for high-strength, flexible, and biodegradable hydrogels in flexible electronics. With dual cross-linking, the chitin hydrogels show tunable mechanical properties to be recycled within enzymatic solutions, thus enabling future integrations of structural and sensing capabilities into shell-based robots. This will enable autonomous systems not only to operate sustainably but even to disappear without trace after completing their mission.
The lobster shell project is part of a continuum of biomimetic propulsion research in terms of actuation. For instance, biohybrid jellyfish have demonstrated in-situ swimming speeds of up to 6.6 cm/s-2.3 times baseline-using electrode-driven muscle contractions validated by hydrodynamic models that couple morphological parameters to thrust. Fin ray effect actuators on soft-rigid fish robots replicate undulatory swimming patterns with tail beat frequencies from 1 to 2.5 Hz, which gives way to efficient cost-of-transport values at higher speeds. Though the performance of lobster shell fins is modest compared with high-speed biomimetic fish, it holds the promise that recycled biological structures can deliver viable aquatic locomotion without complex fabrication.
Engineering challenges remain. Biological variability means that each shell bends differently, making it hard to standardize. Adaptive control systems or tunable synthetic augmentation could compensate, but would require a precise mechanical profiling of every shell. Manufacturing scalability depends on whether the variability can be tolerated or economically managed. The supply chain for raw material-frozen seafood processing waste-is effectively unlimited in regions consuming langoustines, so the resource base is robust. The potential application space is wide. In underwater robotics, shell-based fins could complement soft robotic manipulators in coral reef monitoring where low-impact interaction is critical.
In biomedical engineering, biocompatible shell composites may serve as temporary implants with programmed biodegradation. Environmental monitoring platforms could deploy shell-based robots on short-term missions, avoiding persistent waste in sensitive ecosystems. By fusing evolutionary design with modern actuation and dedication to recyclability, EPFL’s lobster shell robots challenge entrenched assumptions about what constitutes “appropriate” engineering material. Thereby, they unlock a path toward machines that grip, swim, and finally return harmlessly to nature, closing the loop between creation, use, and dissolution.
