Elephant trunks overcome strength-flexibility trade-offs of traditional robotics
Elephant trunks are strong yet sensitive – their thick, wrinkled skin is tough and enables a remarkable sense of touch. This allows elephants to feel textures, forces and shapes as they manipulate objects. Flexible movement and tactile sensing work together to create versatile prehensile tasks without requiring rigid joints. Translating these natural principles into soft robotics, the EU-funded PROBOSCIS(opens in new window) project set out to revolutionise how robots handle objects, creating systems inspired by nature’s dexterity, adaptability and resilience.
How trunk mechanics helps robotic design
At the Adventures with Animals reserve in South Africa, researchers worked closely with trained elephants to study how their trunks handle objects of different shapes and weights. The team from the University of Geneva used motion capture(opens in new window) to track the precise movements of the trunks. In Italy at the ZooSafari in Fasano, researchers from Istituto Italiano di Tecnologia and Scuola Superiore Sant’Anna measured the grasping forces(opens in new window) using custom-designed objects and investigated the reaching behaviour of the trunk, respectively. The research was conducted in collaboration with elephant keepers to ensure the well-being of the animals. To better understand the trunk’s structure and intricate anatomy, the researchers performed high-resolution imaging and tissue analysis on trunks from naturally deceased elephants at Zurich Zoo. Inspired by these findings, the IIT team developed artificial muscles, flexible actuators and tactile skin for a robotic arm. Functional materials were designed by the Hebrew University of Jerusalem(opens in new window) for printing foam-like components at the small scale, while SME partner Photocentric advanced 3D printing techniques to produce soft components for the robot at large scale.
Greater flexibility with fewer components
“We ultimately developed a lightweight, soft robotic arm nearly one metre long that can bend, twist and curl to grasp objects by wrapping around them. This was achieved with only a few actuators, mimicking the elephant’s ability to perform complex movements with simple strategies,” notes project coordinator Lucia Beccai. Unlike state-of-the-art continuum arms, which often face issues including mechanical discontinuities or the challenge of balancing weight against structural stiffness (especially at larger scales), this design overcomes those issues. These challenges likely explain why large continuum arms have yet to gain traction in industrial applications.
What makes elephant trunks an ideal model for robotics
The team from Geneva mapped the intricate muscle distribution in elephant trunks, revealing how they control this complex structure. “Elephants simplify this complexity by stiffening parts of the trunk to guide the movement. It seems that at the distal part of the trunk the force exerted on an object is finely adjusted,” explains Beccai. The trunk’s skin consists of distinct layers that provide strength, elasticity and protection while remaining highly sensitive. These features explain how the trunk balances strength and delicacy, making it a perfect model for robotics. The study also showed that elephants use consistent, repetitive patterns of movement and tactile feedback to interact with their environment efficiently. This inspired control strategies, helping robots sense and handle objects more intuitively and adaptively.
Soft robotics revolutionising diverse industries
PROBOSCIS breakthroughs promise advanced universal grippers for diverse fields including manufacturing, healthcare and rescue operations. “In manufacturing, soft, adaptive manipulators in future could handle various objects, including deformable items, while in food processing, they could gently sort and assess fruits and vegetables without causing damage,” describes Beccai. “In healthcare, they could assist the elderly or disabled with tasks like lifting or handing objects. Ultimately, in rescue missions, these robots could clear rubble, detect victims and operate in challenging conditions like smoke or darkness, where traditional systems fail.”
