In a groundbreaking development, researchers at North Carolina State University have engineered a robotic gripper, employing the ancient Japanese art of kirigami, that is capable of handling delicate and heavy objects with equal ease. The innovative device is gentle enough to lift a droplet of water, robust enough to hoist a weight of 6.4 Kg (14.1 pounds), agile enough to fold fabric, and precise enough to handle microfilms nearly 20 times thinner than a human hair.
The potential applications of this device are vast, from manufacturing to robotics prosthetics. The team has successfully integrated the gripper with technology that allows its operation to be controlled by electrical signals generated by forearm muscles, demonstrating its potential for use in prosthetic limbs.
Developing a single soft gripper that can handle objects ranging from ultra-soft and ultra-thin to heavy has always been a challenge due to the trade-off between strength, precision, and gentleness. “Our design strikes an excellent balance between these characteristics,” said Jie Yin, Associate Professor of Mechanical and Aerospace Engineering at North Carolina State University and the study’s corresponding author.
The design of the new grippers builds on a previous generation of adaptable robotic grippers that used kirigami, a technique involving cutting and folding two-dimensional material sheets to create three-dimensional shapes. The latest design has significantly improved the fundamental structure and trajectory of the grippers, according to Yaoye Hong, co-author of the paper and a recent Ph.D. graduate from NC State.
The unique design allows for high levels of strength and delicacy by distributing force across the structure of the gripper. Despite weighing only 0.4 grams, the grippers can lift up to 6.4 kilograms – a payload-to-weight ratio of about 16,000. This is 2.5 times higher than the previous record for payload-to-weight ratio which was 6,400.
A significant advantage of the new technology is that its impressive characteristics are primarily driven by its structural design rather than the materials used in fabrication. According to Hong, this means that the grippers could be made from biodegradable materials like sturdy plant leaves, making them particularly useful for applications where temporary use is required such as in food handling or biomedical materials.
The researchers also demonstrated the compatibility of the gripping device with a myoelectric prosthetic hand, indicating that the prosthesis is controlled by muscle activity. While it cannot replace all functions of existing prosthetic hands, it could supplement those other functions without needing to replace or augment the existing motors used in robotic prosthetics.
In proof-of-concept testing, the researchers showed that the kirigami grippers could work in conjunction with the myoelectric prosthesis to perform tasks like plucking grapes off a vine and turning book pages. “We believe the gripper design has potential applications in fields ranging from robotic prosthetics and food processing to pharmaceutical and electronics manufacturing. We are eager to collaborate with industry partners to explore ways to put this technology into use,” Yin stated.
The study was co-authored by Yao Zhao and Yanbin Li, postdoctoral researchers at NC State; Joseph Berman, a Ph.D. student at NC State; and Yinding Chi, a former Ph.D. student at NC State. The study received financial support from the National Science Foundation under grants 2005374 and 2221479.
This breakthrough could revolutionize various sectors, including electronics manufacturing, where precision and delicacy are paramount. As computers continue to shrink in size and complexity increases, new methods like this kirigami-based robotic gripper could be instrumental in handling delicate electronic components in the future.
