Soft assistive robotic wearables get a boost

The knitted actuator integrates conductive yarn for sensing, allowing the actuators to “feel” what they touch. The team cooked up several prototypes spanning an assistive glove, a soft hand, an interactive robot, and a pneumatic walking quadruped. Their prototypes, which, by using yellow fabric look a little bit like banana fingers, spanned an assistive glove, a soft hand, an interactive robot, and a pneumatic quadrupedal robot.

While there’s been plenty of movement in the hardware development of soft pneumatic actuators over the years—a 2019 prototype of a collaborative robot used such actuators to reproduce human-like gripping in its hands—the design tools haven’t improved with quite as much speed. Old processes have typically used polymers and molding, but the scientists used a combination of elastic and sensing stitches (with conductive yarn) that allows for programming bending of the actuators when they’re inflated, and the ability to incorporate real world feedback.

For example, the team used the actuators to build a robot that sensed when it was touched specifically by human hands, and reacted to that touch.

The team’s glove can be worn by a human to supplement finger muscle movement, minimizing the amount of muscle activity needed to complete tasks and motions. This could hold a lot of potential for those with injury, limited mobility, or other trauma to the fingers. The method can also be used to make an exoskeleton (wearable robotic units controlled by computer that supplement human motion and restore locomotion and movement); for example, the authors created a sleeve that can help wearers bend their elbow, knee, or other body parts.

“Using digital machine knitting, which is a very common manufacturing method in today’s textile industry, enables ‘printing’ a design in one go, which makes it much more scalable,” says Yiyue Luo, MIT CSAIL Ph.D. student and lead author of a new paper about the research. “Soft pneumatic actuators are intrinsically compliant and flexible, and combined with intelligent materials, have become the backbone of many robots and assistive technologies—and rapid fabrication with our design tool can hopefully increase ease and ubiquity.”