The ability to change shape is essential for enabling multiple functions in biological and artificial systems. Several methods for shape-changing have been suggested for use in metamaterials and robotics. Nonetheless, only a few of these methods have managed to transform into a variety of 3D shapes after being made, using a straightforward actuation and control system.
Taking inspiration from thick origami and hierarchies in nature, engineers at North Carolina State University have developed a method for transforming a single plastic cubed structure into over 1,000 configurations using only three active motors. These findings could lead to the creation of shape-shifting artificial systems capable of serving multiple functions and bearing a load, such as versatile robotic structures for use in space.
“The question we’re asking is how to achieve a number of versatile shapes with the fewest number of actuators powering the shape-shifting,” said Jie Yin, associate professor of mechanical and aerospace engineering and co-corresponding author of a paper describing the work. “Here, we use a hierarchical concept observed in nature – like layered muscle fibers – but with plastic cubes to create a transforming robot.”
To achieve this, the NC State researchers utilized a 3D printer to create hollow plastic cubes and then combined 36 of them using rotating hinges, with some hinges secured using metal pins and others wirelessly activated with a motor.
Using only three active motors, the researchers managed to manipulate the cubes into over 1,000 shapes, such as tunnel-like and bridge-like structures, as well as multi-story architectures.
These untethered transformer bots can navigate forward, backward, and sideways without the use of feet solely by adjusting the structure’s shape. They can also quickly transition from a flat or fully open form to a larger boxlike cube or fully closed shape. Additionally, the bots can carry a load up to three times their own weight.
In their next phase, the researchers will aim to enhance the transformer bots even further.
“We want to make a more robust structure that can bear larger loads,” said Yanbin Li, an NC State postdoctoral researcher and co-corresponding author of the paper. “If we want a car shape, for example, how do we design the first structure that can transform into a car shape? We also want to test our structures with real-world applications like space robots.”
“We think these can be used as deployable, configurable space robots and habitats,” said Antonio Di Lallo, an NC State postdoctoral researcher and co-first author of the paper. “It’s modular, so you can send it to space flat, assemble it as a shelter or as a habitat, and then disassemble it.”
“For users, it needs to be easy to assemble and control,” Yin said.
Journal reference:
- Yanbin Li, Antonio Di Lallo, Junxi Zhu, Yinding Chi, Hao Su & Jie Yin. Adaptive hierarchical origami-based metastructures. Nature Communications, 2024; DOI: 10.1038/s41467-024-50497-5
