Origami-inspired soft robot gets a grip on fragile objects

An origami-inspired robot could one day be used on assembly lines, in surgery or even in outer space.

TWISTER, an origami-inspired soft robot (credit Russell Lee)
TWISTER, an origami-inspired soft robot (credit Russell Lee)

TWISTER (TWISted TowEr Robot) is a patent-pending 3D-printed soft robot developed by Case Western Reserve University’s Kiju Lee, the Nord Distinguished Assistant Professor of Mechanical and Aerospace Engineering at CWR.

According to CWU, TWISTER was inspired by an origami twisted tower that uses multiple origami segments to form a tower structure. This origami design was then reinvented for various potential applications in robotics and manufacturing.

In earlier work using paper-folded structures, Lee’s team added three small versions of the towers to one end of the larger tower and manipulated them to grasp like three opposing fingers. While picking up and moving eggs and ripe fruit, Lee’s team found that when excessive force was applied, the fingers absorbed the extra force by distributing it and deforming.

That quality, the researchers said, demonstrates the design’s potential for manipulating fragile objects without requiring force-based sensing and interacting with humans, without safety concerns.

“Among the possibilities for this robot are fragile-object manipulation and direct human-robot interaction, because these robots are soft and safe,” said Lee, who presented her latest study at the IEEE/RSJ International Conference on Intelligent Robots and Systems in Vancouver on September 27, 2017.

TWISTER is made from multiple layers of regular polygons – triangles, hexagons or octagons – forming a tube-like shape of a tower.

Lee used cable-based actuation to control the robot, while different approaches, such as using Shape-Memory-Alloys, are also being explored. The motions can make a tower lying on its side crawl.

For safety reasons, hard-bodied robots are typically separated from people in manufacturing processes, Lee said. “Because this robot can be made with soft materials,” she said, “it could be safe to use on an assembly line right next to people.”

Lee and doctors have also been discussing ways to miniaturise the robot to insert in the body for minimally invasive surgeries.

“Laproscopic surgery often requires some rigid pieces, and movement to control them from the outside causes stress on the tissues,” Lee said.

She’s also considered space robotic applications, particularly for a space arm.

“To put anything into space, volume and weight are critical, because of the cost of rocket transport,” Lee said. “This robot is fully collapsible and, compared to a rigid arm, light and compact.”