Common push puppet toys in animal and celebrity shapes can move or fall by pressing a button on the base of the toy. Now, a team of UCLA engineers has developed a new class of tunable dynamic materials that mimic the inner workings of pushrods with applications for soft robotics, reconfigurable architectures and space engineering.
Inside a push puppet, there are connecting cords, which, when pulled, tighten the toy. But loosening these cords will make the toy's “limbs” limp. Using the same bone tension-based principle that controls a puppet, researchers have developed a new type of metamaterial, a material engineered to have properties with advanced capabilities. .
Published in Content horizonThe UCLA study reveals a new lightweight metamaterial, equipped with motorized or self-propelled cords connected by beads attached to an interconnected cone. Upon activation, the cords are pulled tightly, causing the nested chain of bead particles to jam and straighten into a line, hardening the material while maintaining its overall structure.
The study also unveiled versatile properties of the material that could lead to its eventual incorporation into soft robotics or other programmable structures:
- The level of tension in the cords can consequently “tune” the stiffness of the structure — the fully rigid state offers the strongest and stiffest surface, but incremental changes in the tension of the cords provide flexibility to the structure. It also gives flexibility. The key is the correct geometry of the nest cones and the friction between them.
- Structures that use the design can collapse and stiffen repeatedly, making them useful for long-lasting designs that require repeated movement. The material also offers easy transportation and storage in its non-deployable, limp state.
- After deployment, the material clearly shows tunability, becoming more than 35 times stiffer and changing its damping capacity by up to 50%.
- Metamaterials can be designed to self-actuate via artificial tendons that animate the shape without human control.
“Our metamaterial enables new capabilities, demonstrating its great potential for applications in robotics, reconfigurable structures and space engineering,” said corresponding author and UCLA Samueli School of Engineering postdoctoral scholar Wenzong Yan. “Made with this material, for example, a self-deployable soft robot can adjust its limbs to accommodate different terrains for maximum mobility while maintaining its body structure. can fix the stiffness.”
“The general concept of contractile metamaterials opens up exciting possibilities for building mechanical intelligence in robots and other devices,” Yan said.
A 12-second video of the metamaterial in action is available here, via the UCLA Samueli YouTube channel.
Senior authors on the paper are Ankur Mehta, UCLA Samueli associate professor of electrical and computer engineering and director of the Laboratory for Embedded Machines and Ubiquitous Robots, of which Yan is a member, and Jonathan Hopkins, professor of mechanical and aerospace engineering. Those who lead. UCLA's Resilience Research Group.
According to the researchers, potential applications of the material include self-assembling shelters with shells that encapsulate collapsible scaffolds. It can also act as a compact shock absorber with programmable damping capabilities for vehicles traversing rough environments.
“Looking forward, there is a lot of room to explore tailoring and customization capabilities by changing the size and shape of the beads, as well as how they are connected,” said Mehta, who has mechanical and There is also a UCLA faculty appointment in aerospace engineering.
While previous research has explored contracting cords, this paper examines the mechanical properties of such systems, including ideal shapes for bead alignment, self-assembly and tuning to maintain their overall framework. The ability to be done is included.
Other authors of the paper are UCLA mechanical engineering graduate students Talmadge Jones and Ryan Lee — both members of the Hopkins lab — and Christopher Javitz, a Georgia Institute of Technology graduate student who conducted the research as a member of the Hopkins lab. I participated. Was an undergraduate aerospace engineering student at UCLA.
The research was funded by the Office of Naval Research and the Defense Advanced Research Projects Agency, with additional support from the Air Force Office of Scientific Research, as well as computing and storage from the UCLA Office of Advanced Research Computing. Services were also included.