Traditional ‘cut and sew’ methods have been the primary approach for creating soft robotics, which offer several benefits over rigid robots, including inherent safety and flexibility. However, these methods have limitations, SEAS said in a press release.
"Every seam adds costs, and potential points of failure. For manufacturing complex robotic devices, this can be a big challenge," said Vanessa Sanchez, the first author of the paper and a former PhD student in Wood's lab at Harvard.
Inspired by the efficiency and minimal waste of 3D knitting in the textile industry, Sanchez and her team repurposed a vintage punch card knitting machine and collaborated with knitting experts from the Rhode Island School of Design, Parsons School of Design, and the Fashion Institute of Technology.
The researchers also partnered with James McCann, an assistant professor at the Carnegie Mellon Robotics Institute, to develop a software for automating the knitting process. Traditional knitting design software could not meet their needs as it generally focuses on single outputs rather than parametric families of outputs, which the team wanted to explore.
The team solved this problem by using a knitout file format to describe 3D patterns. The format is written in general-purpose programming languages, making it possible to translate the descriptions to run on their knitting machine.
"Other groups with different types of knitting machines can use and build on the same patterns, without extensive translation effort," McCann said.
Once they established the 3D knitting process, the team conducted a series of tests to understand how different knitting parameters influenced the mechanical properties of the resulting material. They experimented with 20 different combinations of yarn, structure, and other parameters, studying how varied knit architectures affected folding, unfolding, structural geometry, and tensile properties, the release added.
The team demonstrated the versatility of their approach by creating several knit robot prototypes, including gripper devices with bending and grasping appendages, a multi-chamber claw, an inchworm-like robot, and a snake-like actuator capable of lifting objects much heavier than itself.
“We wanted to create a library for engineers to draw from to develop a variety of soft robots, so we characterised the mechanical properties of many different knits,” Sanchez said. “3D knitting is a new way of thinking about additive manufacturing, about how to make things that could be reconfigured or redeployed. There are already industrial machines to support this type of manufacturing—with this initial step, we think our approach can scale and translate out of the lab.”
ALCHEMPro News Desk (DP)
Receive daily prices and market insights straight to your inbox. Subscribe to AlchemPro Weekly!
marketing@alchempro.com
