Traditionally, robots have been machine-like, rigid, fast and efficient contraptions, much like Doctor Who’s Cybermen and Tony Stark’s Iron Man suit.
But, researchers at École polytechnique fédérale de Lausanne’s (EPFL) Reconfigurable Robotics Lab (RRL) have turned this notion on its head with their soft robots.
These flexible, reconfigurable and air-actuated robots behave like human muscles and could be used in physical rehabilitation.
The soft robots are powered by muscle-like actuators, and are designed to be used on the human body to help people move, particularly for those undergoing physical rehab.
Made of elastomers, including silicon and rubber, they are controlled by changing the air pressure in specially designed ‘soft balloons’, which also act as the robot’s body.
In addition to patient rehabilitation, these soft robots can be used to handle fragile objects, in biomimetic systems, as well as for home care.
“Our robot designs focus largely on safety,” explained Jamie Paik, RRL director. “There’s very little risk of getting hurt if you’re wearing an exoskeleton made up of soft materials, for example.”
In an article published in Nature – Scientific Reports, the researchers showed that their model can accurately predict how a series of modules moves. The cucumber-shaped actuators, as seen in the video, can stretch up to five or six times their normal length and bend in two directions.
“We conducted numerous simulations and developed a model for predicting how the actuators deform as a function of their shape, thickness and the materials they’re made of,” said Gunjan Agarwal, lead author.
A test was conducted to show that different materials could be used in the construction of the soft robot. One of the variants, for example, consisted of covering the actuator in a thick paper shell.
“Elastomer structures are highly resilient but difficult to control,” Agarwal explained. “We need to be able to predict how, and in which direction, they deform. And because these soft robots are easy to produce but difficult to model, our step-by-step design tools are now available online for roboticists and students.”
Other researches from RRL have been working to develop these soft robots for medical purposes.
One of their designs is a belt made from several inflatable components, which holds patients upright during rehabilitation exercises and guides their movements.
“We are working with physical therapists from the University Hospital of Lausanne (CHUV) who are treating stroke victims,” said Matthew Robertson, the researcher leading the project. “The belt is designed to support the patient’s torso and restore some of the person’s motor sensitivity.”
But the potential applications for the soft actuators used in these robots are endless. The EPFL team, for example, is using the technology to develop adaptable robots capable of navigating in cramped or hostile environments.
Because they are soft and flexible, the robots should be able to withstand squeezing and crushing.
“Using soft actuators, we can come up with robots of various shapes that can move around in diverse environments,” Paik noted. “They are made of inexpensive materials, and so they could easily be produced on a large scale. This will open new doors in the field of robotics.”