Researchers Develop "Programmable Balloons," for Soft Robotics, Using Kirigami Techniques
Based on the Japanese art of paper-cutting, these kirigami balloons can be programmed to morph on-demand into a variety of shapes.
Researchers at Harvard's John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed "programmable balloons," based on kirigami sheets that can morph their shape on-demand — and say the technology could be used for soft robotics and medical devices.
"Kirigami, the Japanese art of paper cutting, has recently enabled the design of stretchable mechanical metamaterials that can be easily realized by embedding arrays of periodic cuts into an elastic sheet," the researchers explain in the paper's abstract. "Here, kirigami principles are exploited to design inflatables that can mimic target shapes upon pressurization."
"The system comprises a kirigami sheet embedded into an unstructured elastomeric membrane. First, it is shown that the inflated shape can be controlled by tuning the geometric parameters of the kirigami pattern. Then, by applying a simple optimization algorithm, the best parameters that enable the kirigami inflatables to transform into a family of target shapes at a given pressure are identified."
"Furthermore," the researchers continue, "thanks to the tessellated nature of the kirigami, it is shown that we can selectively manipulate the parameters of the single units to allow the reproduction of features at different scales and ultimately enable a more accurate mimicking of the target."
"This work provides a new platform for shape-morphing devices that could support the design of innovative medical tools, actuators, and reconfigurable structures," adds Professor Katia Bertoldi, senior author, of the study.
"By only varying two parameters of the [kirigami cut], we can program all different kinds of crazy shapes into the kirigami balloons, including bends, twists and expansions," says co-first author Dr. Antonio Elia Forte. “Our strategy allows us to automatically design a morphable balloon starting from the shape that you need. It’s a bottom-up approach that for the first time harnesses the elasticity of the material, not only kinematic."
The team's work has been published under closed-access terms in the journal Advanced Materials.