Soft robot that mimics human hand movements designed

Harvard researchers have developed a new model to design a soft robot that bends like an index finger and twists like a thumb when powered by a single pressure source.

Designing a soft robot that can bend like a finger or knee may seem simple but the motion is actually incredibly complex, researchers said. "Rather than designing these actuators empirically, we wanted a tool where you could plug in a motion and it would tell you how to design the actuator to achieve that motion," said Katia Bertoldi from Harvard John A Paulson School of Engineering and Applied Sciences (SEAS) in the US.

"The design is so complicated because one actuator type is not enough to produce complex motions," said Fionnuala Connolly from SEAS. "You need a sequence of actuator segments, each performing a different motion and you want to actuate them using a single input."

The method developed by the team uses mathematical modelling of fluid-powered, fiber-reinforced actuators to optimise the design of an actuator to perform a certain motion. They used this model to design a soft robot that bends like an index finger and twists like a thumb when powered by a single pressure source.

"This research streamlines the process of designing soft robots that can perform complex movements," said Conor Walsh from the Wyss Institute for Biologically Inspired Engineering in the US. "It can be used to design a robot arm that moves along a certain path or a wearable robot that assists with motion of a limb."

The study was published in The Proceedings of the National Academy of Sciences.