Researchers at the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland have introduced an impressively versatile yet lightweight robotic technology: an elephant robot made with 3D printing. The 3D-printable lattice structure is made from simple foam, but it can be precisely programmed to simulate both soft and rigid tissues from a flexible trunk to stiff joints like the hip or knee. True to its name, the adorable elephant robot can, among other things, pick up flowers with its trunk, move like a real elephant, and looks simply cute.
The secret to the robot lies in its so-called cells—tiny units of the lattice whose shapes and positions can vary. The EPFL researchers used two basic models: body-centered cubic (BCC) and the X-cube. By continuously blending these structures and additionally rotating or shifting individual cells, they create an almost infinite range of mechanical properties. A lattice cube with four cells offers about 4 million configurations; with five cells, the number grows to over 75 million. “This approach enables the continuous spatial blending of stiffness profiles and allows for an infinite range of blended unit cells. It’s particularly suited for replicating the structure of muscular organs like an elephant trunk,” said PhD candidate Benhui Dai about the project.
The elephant robot’s trunk can, among other things, grasp a flower.
The Interplay Between Flexible and Rigid Printed Parts
Using this flexibility, the roboticists were able to build a mechanically diverse elephant robot. Certain segments of the trunk consist of spiral, twisting, and bending sections that enable soft, flowing movements, while other parts are deliberately made stiffer, much like bones or tendons. This kind of technology is especially valuable in medical engineering, for example in the manufacturing of prosthetics. Several joint types were replicated: sliding planes (similar to the bones in the foot), uniaxial bends like those in the knee, and complex biaxial movements like toe joints.
The researchers led by Josie Hughes at EPFL’s CREATE Lab emphasize that this approach enables a new class of mechanically adaptive robots. The combination of light weight and variable stiffness makes it ideal for future mobile systems, such as amphibious robot projects where mobility in fluid environments is critical. Hughes explains, “Like honeycomb, the strength-to-weight ratio of the lattice can be very high, enabling very lightweight and efficient robots. The open foam structure is well-suited for motion in fluids, and even offers potential for including other materials, like sensors, within the structure to provide further intelligence to foams.”
Thanks to the special printing technology, the robot is able to mimic complex movements.
Its Capabilities Mirror the Real Thing
The robot demonstrates impressive capabilities: its soft trunk can grasp, twist, and bend, while the rigid legs provide stability and enable powerful movements. Although no direct practical applications have been mentioned so far, the publication in Science Advances is likely to inspire many fields, from soft robotic arms in medicine to robotic platforms that adapt to changing loads or environments.
The EPFL research marks an important step toward bio-inspired robotics, where not only the shape but also the mechanical function is determined by structural design. A single foam material can thus become an adaptive, muscle and bone-like system, bringing it impressively close to its living counterpart. You can find more information HERE.
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Photo Credit: EPFL