Widely popular push puppets in various animal and human shapes transform or retract at the touch of a simple button on their compact bases, delighting children and adults alike. A team of UCLA engineers has developed a novel class of dynamically tunable materials inspired by the mechanisms found in push puppets, with potential applications in soft robotics, reconfigurable structures, and surface engineering.
Within a traditional pull-along puppet, delicate strings exist that, upon being carefully drawn taut, enable the figurine to maintain a rigid stance. As you relax the tension on these strings, the toy’s limbs will surrender to gravity, becoming soft and flaccid. Researchers have leveraged the same principle governing puppet strings – twine tension – to create a novel metamaterial, a meticulously designed material boasting extraordinary capabilities through its manipulated properties.
Published by UCLA researchers, a groundbreaking study showcases a novel lightweight metamaterial that incorporates either motor-driven or self-activating strings, woven through interconnected cones bearing bead-like structures. Upon activation, the cords contract, causing the beaded particles to align in a linear formation, rendering the fabric rigid yet preserving its overall structure.
The examination further revealed the material’s adaptable nature, which ultimately led to its integration into soft robotics and other reconfigurable structures.
- The degree of tension within cord systems can precisely “calibrate” the resulting structure’s rigidity – a perfectly taut state optimizes stiffness and strength, while incremental adjustments allow for controlled flexibility without sacrificing energy. The key lies in the precise geometry of the nesting cones’ interplay and the subtle friction that exists between their surfaces.
- Structures incorporating this design concept exhibit a unique ability to repeatedly collapse and stiffen, rendering them ideal for long-term applications where repetitive stress is inherent. With its ability to remain limp and compact when not in use, the fabric offers effortless transportation and storage options.
- Following deployment, the material exhibits striking tunability, demonstrating a significant stiffening of more than 35 times and a remarkable 50% alteration in damping properties.
- The metamaterial could potentially be engineered to self-activate through synthetic tendons that trigger its formation without human intervention?
Researchers have developed a groundbreaking metamaterial that unlocks novel applications, showcasing immense promise in integrating with robotics, adaptable structures, and spatial design. According to Dr. Wenzhong Yan, the material’s inventor and UCLA Samueli College of Engineering postdoctoral fellow, this innovation holds vast potential for revolutionary advancements. Developed from these innovative materials, a self-deploying gentle robotic, for example, could fine-tune the stiffness of its limbs to adapt seamlessly to diverse terrain conditions, ensuring optimal movement while maintaining its overall structural integrity. The robust metamaterial could also enable robots to efficiently lift, push, or pull objects.
“The notion of contractible-cord metamaterials paves the way for innovative approaches to integrating mechanical intelligence into robots and other devices, said Yan.”
Watch a 12-second video of this groundbreaking metamaterial in action on the UCLA Samueli YouTube Channel.
The senior authors on this paper are Ankur Mehta, an affiliate professor at UCLA Samueli’s electrical and computer engineering department, director of the Laboratory for Embedded Machines and Ubiquitous Robots where Yan is a member, and Jonathan Hopkins, a mechanical and aerospace engineering professor who leads UCLA’s Versatile Analysis Group.
According to researchers, this innovative fabric has the potential to serve multiple purposes, including the development of self-assembling shelters featuring shells that encase collapsible scaffolding systems. It could also serve as a compact shock absorber with programmable damping capabilities, effectively smoothing the ride for autonomous vehicles navigating challenging terrain.
“Looking ahead, vast opportunities await for exploring innovative applications of bead customization, including manipulating their shape and size, as well as their interconnectedness,” said Mehta, who holds a joint appointment at UCLA’s Department of Mechanical and Aerospace Engineering.
While prior research has focused on contracting cords, this study undertakes a comprehensive examination of the mechanical characteristics of these systems, including optimal bead arrangements, self-assemblage capabilities, and the adaptability to support their overall structure.
The authors of this paper are Talmage Jones, Ryan Lee, and Christopher Jawetz, all students in the mechanical engineering graduate program at UCLA, with Jones and Lee working under the guidance of Dr. Hopkins’ lab, and Jawetz contributing as an undergraduate student from UCLA’s aerospace engineering department while affiliated with Dr. Hopkins’ lab during his undergraduate studies at Georgia Institute of Technology.
The research was supported by the Office of Naval Research and the Defense Advanced Research Projects Agency, with additional assistance from the Air Force Office of Scientific Research, as well as computational and storage resources provided by the University of California, Los Angeles, Office of Information Technology and Advanced Research Computing.
