Improved fluidic robot paves the way for untethered soft robotics

Soft robots may be the future of robotics, but there are still many limitations in their design. One big problem is that soft robots generally need to be tethered, meaning that they have to be connected to an external device by wires which supply compressed air and control their systems. This limits their functionality for situations like space exploration, search and rescue, or medical surgeries.

Now a team of researchers from Harvard University has taken a first step towards untethering soft robots. They have developed a method to replace multiple control systems with just one input, which simplifies the design of the robots as well as reducing their weight.

“Before this research, we couldn’t build fluidic soft robots without independently controlling each actuator through separate input lines and pressure supplies and a complex actuation process,” Nikolaos Vasios, a graduate student at the John A. Paulson School of Engineering and Applied Sciences (SEAS) and first author of the paper, explained in a statement. “Now, we can embed the functionality of fluidic soft robots in their design, allowing for a substantial simplification in their actuation.”

This new, simplified soft robot, powered by pressurized air, replaces multiple control systems with one input, reducing the number, weight, and complexity of the components needed to power the device. Bertoldi Lab/Harvard SEAS

The development uses fluid at different viscosities to control the speed at which air moves through the robot. By using tubes of different diameters, the team was able to control the viscosity of the fluid and therefore the speed of airflow. Now only one input is required which pushes air through the tubes at a steady rate. It is the tubes themselves which determine the speed of the airflow, so complex air compression calculations are no longer required.

“Our work presents for the first time a strategy that can be used to make simply actuated fluidic soft robots, based on this well-known phenomenon of viscous flow,” Katia Bertoldi, the leader of the group and a Professor of Applied Mechanics at Harvard, said in the same statement. “With the strategy presented in our work, the actuation of fluidic soft robots will now be simpler and easier than ever, taking a major step towards fully untethered and simply actuated soft robots.”

The research is published in the journal Soft Robotics.

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