Colorado State researchers build elephant-trunk-inspired robots that bend, grip and link up

Engineers at Colorado State University have built bendable, tube-shaped robots modeled on elephant trunks. The machines can grasp objects and attach to one another, according to a report by Interesting Engineering. The team says groups of them could eventually assist with space exploration and other complex tasks.

The robots are built on a design known as tensegrity, in which rigid rods are kept in place by a network of tensioned cables instead of fixed joints. This lets the body bend, stretch, collapse and change shape while holding its structure together, the researchers said.

The system functions like an elephant's trunk to grip objects. Photo: Interesting Engineering

Claws at both ends

Each tube-like robot has a mechanical gripping claw at either end. The claws let a unit pick up objects or fasten onto other robots. Conventional robotic arms rely on fixed joints, whereas these bodies can deform continuously.

According to the report, the mechanical attachment avoids magnetic connections and helps reduce alignment problems when several units join. Connected robots can form chains, loops and branching structures, each suited to different kinds of movement and manipulation.

The team's goal is to merge the pliability of soft robots with the ability of modular systems to rearrange themselves. Existing modular robots typically use rigid parts, which limits how well they adapt to different environments and tasks, the report said.

Tests and limits

The team said individual units could manipulate objects and move on their own, while connected groups coordinated their motions to transport items. The robots also showed multimodal locomotion, meaning they used different movement strategies to cross varied environments, and loco-manipulation, which combines moving and handling objects.

Testing took place in laboratories and in real-world settings, including natural landscapes. The researchers said choosing motors was among the engineering challenges, because the actuators had to be small enough to fit inside the robots yet powerful and reliable enough for varied motions.

The robots are not yet fully autonomous. Most operations currently require a human pilot, although the team has shown that two units can find each other and connect without help.

Future work will focus on greater autonomy, higher speeds and operation alongside humans with less supervision. The researchers also envision groups of tens or hundreds of linked units that travel to a site and then rearrange themselves for a specific job. Possible uses include manufacturing, space exploration and search-and-rescue missions.