Desktop Printing of Soft Robots with Integrated Fluidic Control Circuits

Soft bodied robots have promising applications including dexterous manipulation, locomotion in complex environments, and safe interaction with humans. However, the control of soft robots has typically required complicated components such as pumps, valves, and electronics making them difficult and expensive to manufacture and recycle. This award supports research to understand how to print soft robots (including their body, actuators, and control circuitry) in one piece out of a single material, using commercially available desktop 3D printers. A key innovation is to control the robots with embedded circuits that run on compressed gas rather than electricity, with soft 3D printed components acting as transistors, sensors, etc. The knowledge gained through this work will advance the science of robotics by providing a new approach to the manufacture of robots that can be printed all at once on consumer grade hardware and can go into operation immediately. The research will advance national health, prosperity, and welfare by enabling the rapid development of inexpensive soft robotic devices tailored to real-world applications, including for education, environmental monitoring, medical devices, and space exploration. The outcomes could further lead to future robots that are fully recyclable or biodegradable. This award will also provide opportunities to educate and train graduate and undergraduate students in multidisciplinary research incorporating robotics, fluid mechanics, and materials science, as well as opportunities for STEM outreach to K-12 students, with a focus on including students who are members of the underrepresented groups. The fabrication of soft robots has previously required complex fabrication processes, exotic materials, or both. This research aims to achieve monolithically printed functional soft robots with embedded fluidic control circuits using popular desktop extrusion (fused filament) 3D printing from commercially available soft materials (thermoplastic polyurethanes). Using a pressurized gas as an energy source for both actuation and computation, this work will eliminate the need for assembly or multi-material 3D printing. Component stiffness will be tuned by varying geometry. An open-source design tool will encode design rules for achieving functional pneumatic components with extrusion printing. This will be followed by an investigation of the underlying physics connecting design parameters to the performance of a fundamental set of 3D printed pneumatic components. This experience will be subsequently used to print integrated pneumatic components required for the control of soft robots. Finally, the cumulative knowledge will enable the monolithic 3D printing of functional, agile soft robots with embedded sensors and feedback control circuits. This project is supported by the cross-directorate Foundational Research in Robotics program, jointly managed and funded by the Directorates for Engineering (ENG) and Computer and Information Science and Engineering (CISE). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.