These Real-World Transformers Use a 3D-Printed Soft Actuator to Flip Locomotive Modes

Flipping between two states with the application of power, this soft rubber actuator offers real flexibility.

Gareth Halfacree
11 days agoRobotics / 3D Printing

Researchers from Carnegie Mellon University and the University of California have designed a novel actuator that can be used to built more flexible soft robots — including machines capable of transforming between walking on land land swimming across the sea.

"We were inspired by nature to develop a robot that can perform different tasks and adapt to its environment without adding actuators or complexity," explains first author Dinesh K. Patel, a post-doctoral fellow in Carnegie Mellon's Morphing Matter Lab. "Our bistable actuator is simple, stable and durable, and lays the foundation for future work on dynamic, reconfigurable soft robotics."

A new soft actuator lets robots be real transformers, flipping between modes in an instant. (📹: Patel et al)

The actuator itself is relatively simple, produced from rubber on a 3D-printer — but is fitted with shape-memory alloy springs. When an brief electrical current is applied, the springs cause the actuator to snap into its second configuration — where it remains until a second current is applied to snap it back again, hence "bistable."

To prove the actuator's flexibility, the team built a series of robot prototypes. The first is a true transformer, capable of using the curved actuators as propellers in the water then flipping them into functional legs for locomotion across the land. A second prototype can switch between crawling and jumping, while a caterpillar-inspired third can crawl or roll.

"You need to have legs to walk on land, and you need to have a propeller to swim in the water. Building a robot with separate systems designed for each environment adds complexity and weight," says Xiaonan Huang, assistant professor of robotics and co-author of the paper, of the prototype. "We use the same system for both environments to create an efficient robot."

Being primarily made from a dense rubber helps with durability, too: the prototype actuators were tested to hundreds of state-changes with no loss of performance, and even subjected to a torture test by having a researcher repeatedly run over them with a bicycle to no ill effect. The team has also suggested the possibility to replace the electrically-actuated springs with heat-actuated versions for broader applications including environmental monitoring and haptic interfaces.

The researchers' work has been published under open-access terms in the journal Advanced Materials Technologies.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire:
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