3D-printed, air-powered modules help control soft robots

A team of researchers from the University of Freiburg have developed 3D-printed pneumatic logic modules that can control the movements of soft robots using air pressure. Soft robots could be used to perform tasks that cannot be carried out by conventional robots. These soft robots could be used in terrain that is difficult to access and in environments where they are exposed to chemicals or radiation that would harm robots made of metal. This requires soft robots to be controllable without any electronics, which is a challenge.

The 3D-printed pneumatic logic modules developed by the researchers enable logical switching of the air flow and can thus imitate electrical control. The modules make it possible to produce flexible and electronics-free soft robots entirely in a 3D printer using conventional filament printing material. The researchers, led by Dr Stefan Conrad and Dr Falk Tauber, published their research findings in the journal Science Robotics.

Tauber said the researchers’ design makes it possible for anyone with 3D printing experience to produce such logic modules and use them to control a soft robot without the need for high-end printing equipment. “This marks a significant step towards completely electronics-free pneumatic control circuits that can replace increasingly complex electrical components in soft robots in the future,” Conrad said.

The modules consist of two pressurised chambers, with a 3D-printed channel running between them. By compressing the channel, the expanding chambers can stop the air flow in it and regulate it like a valve. By opening and closing the valve in a targeted manner, the modules can perform the Boolean logic functions “AND”, “OR” and “NOT” in a similar way to electrical circuits and direct the air flow into the movement elements of the soft robot.

The chambers into which air pressure is applied help to determine what function the individual module performs. Depending on the material selected, the modules can be operated with a pressure of between 80 and more than 750 kilopascals. Compared to other pneumatic systems, they have a fast response time of around 100 milliseconds. Tauber said the modules have a range of potential applications.

“We have developed a flexible 3D-printed robotic walker that is controlled by an integrated circuit using air pressure. The flexibility of the logic modules is demonstrated by the fact that this walker can even withstand the load of a car driving over it,” Tauber said.

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