The same qualities that make a knitted sweater comfortable and easy to wear might soon allow robots to better interact with humans.
- The RobotSweater that has been developed by a research team from Carnegie Mellon University's Robotics Institute is a machine-knitted textile "skin" that can sense contact and pressure, the university has announced.
- The researchers were led by assistant professors in the School of Computer Science (SCS), Changliu Liu, James McCann and Wenzhen Yuan. Yuan is also director of the RoboTouch lab.
- The team—including SCS graduate students Zilin Si and Tianhong Catherine Yu, and visiting undergraduate student Katrene Morozov from the University of California, Santa Barbara—will present the RobotSweater research paper this week at the 2023 IEEE International Conference on Robotics and Automation (ICRA).
The Way it Works: Just as knitters can take any kind of yarn and turn it into a sock, hat, or sweater of any size or shape, the knitted RobotSweater fabric can be customised to fit uneven three-dimensional surfaces.
- Once knitted, the fabric can be used to help the robot "feel" when a human touches it, particularly in an industrial setting where safety is paramount.
- Current solutions for detecting human-robot interaction in industry look like shields and use very rigid materials that cannot cover the robot's entire body because some parts need to deform.
- But, with RobotSweater, the robot's whole body can be covered, so it can detect any possible collisions.
- The RobotSweater's knitted fabric consists of two layers of yarn made with metallic fibres to conduct electricity. Sandwiched between the two is a netlike, lace-patterned layer.
- When pressure is applied to the fabric—say, from someone touching it—the conductive yarn closes a circuit and is read by the sensors.
- The force pushes together the rows and columns to close the connection. If there's a force through the conductive stripes, the layers would contact each other through the holes.
The Other Challenge: The research team faced another challenge in connecting the wiring and electronics components to the soft textile.
- There was a lot of fiddly physical prototyping and adjustment. The team managed to go from something that seemed promising to something that actually worked.
- What worked was wrapping the wires around snaps attached to the ends of each stripe in the knitted fabric.
- Snaps are a cost-effective and efficient solution, such that even hobbyists creating textiles with electronic elements, known as e-textiles, could use them.
- Once fitted to the robot's body, the RobotSweater can sense the distribution, shape and force of the contact. It's also more accurate and effective than the visual sensors most robots rely on now.
