Soft robotic arm could put objects in reach for wheelchair users

Through the four-year project, robotics engineering researchers Cagdas Onal, Berk Calli, and Loris Fichera from Worcester Polytechnic Institute (WPI) in Worcester, Massachusetts, are developing a framework for the design, modelling, and control of soft continuum robotic arms that are more flexible than traditional robot arms. The research is funded by a $1,314,792 award from the US National Science Foundation (NSF). 

“The basic scientific discoveries we are making in this research address real-world challenges for people who use wheelchairs and need devices that will help them grab out-of-reach objects,” said Onal, who is principal investigator on the project and an associate professor in the WPI Department of Robotics Engineering. “A new class of lightweight, safe robotic arms based on the breakthroughs we are making would give those individuals more independence in their daily activities.”

 According to WPI, soft continuum robotic arms expand, shrink, and bend along their entire length to move in different directions and travel around objects, thereby making soft robotics a promising technology in complicated human environments. However, soft robotic arms also tend to be weaker, shakier, and less precise than traditional robot arms made from rigid materials.

To address the weaknesses of soft robotic arms, the researchers are developing origami-inspired designs and novel fabrication methods for modules made of lightweight plastics, 3D printed components, and off-the-shelf items such as sensors and cables.

By folding flat sheets of clear plastic into springy tube-like structures, the researchers are creating modules that are strong, stiff, and resistant to twisting, all while remaining lightweight. The researchers are also developing specialised algorithms that can run on microcontroller platforms to direct the motion and reactions of a robotic arm.

“Soft robots have big potential for assistive robotics,” said Calli, an associate professor in robotics engineering. “You would need a very large, rigid robot to reach the high shelves of a cabinet, for example, and installing such robots next to a user does not make sense. Soft robots could expand to reach objects and shrink to a compact size when not in use, and they would be safer for users than rigid robots. Our project will enable soft robotics for assistive uses by developing novel sensing, control, and AI technologies.”