Luyang Zhao, Guarini ’25, shows modular robots assembling into shelter scaffolding. Darthmouth
Researchers at Dartmouth College have created modular robots that can assemble into structures and move through real-world terrain. Built from cube-shaped blocks, the robots combine rigid rods with soft, adjustable strings that control their shape.
The team recently tested the system outside, marking one of the first demonstrations of modular robots in varied outdoor environments.
Blocks with flexible design
Graduate students Luyang Zhao and Yitao Jiang led the testing near campus. The robots crawled under fallen logs, squeezed through narrow spaces, and connected into scaffolds to support makeshift tents.
With the help of a drone, they even located and “rescued” a disabled module.
“Modular robots are versatile. By combining the blocks differently, we can use them in many different ways,” says Zhao, who built the robots with collaborators at the Dartmouth Reality and Robotics Lab, Rutgers University, and Yale University.
The modules draw inspiration from ants, which form chains to bridge gaps. Connected blocks created a bridge across a brook and carried lightweight objects.
The researchers also placed a board across a chain of blocks to make a stretcher. That stretcher supported a human dummy, though the robots cannot carry people yet.
Zhao says their lightweight and quick deployment make them useful in emergency response. “The robots are lightweight and deployable but also quite robust. They can be air-dropped anywhere and quickly assembled into a bridge or support a temporary shelter.”
Each block has eight rods extending from a 3D-printed center. Inside sits a battery and Wi-Fi module, enabling untethered communication and mobility. On a single charge, a block can “walk” for more than three hours, Zhao says.
Motors on the end-caps adjust the tension of the strings, changing the block’s shape. The caps also include latches, allowing blocks to connect. Small deformations in the blocks add up to significant motion when they join together.
“One of the coolest things about the robot is that you can get quite a bit of motion out of the aggregate system from small deformations of the individual robots,” says Devin Balkcom, professor of computer science and the study’s principal investigator. “The units built out of the pieces combine the structure and the motion together in a very nice way.”
Drones expand possibilities
Drones allow the robots to assemble taller, more complex shapes. While the modules can connect easily on the ground, climbing to build vertical structures is harder. Drone assistance helps overcome gravity and enables the robots to form 3D structures.
“The team’s use of drones to create 3D structures is a game changer,” says Balkcom. “Drone deployment makes it somewhat like 3D printing. You can configure and reconfigure the modules to make these big, tall structures.”
The team described the work in Nature Communications. Zhao, now an assistant professor at Clemson University, says the next steps include boosting weight capacity and adding sensors for autonomy.
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