Manufacturing the Next-Generation of Soft Robotics with Ultra-Efficient, Strong, Electro-Mechanical Artificial Muscles

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As humans start to interact more with robots, we will require adaptable machines in a variety of shapes: manufacturing robots to work side-by-side with people, wearable devices to rehabilitate from injury, smart prosthetics to augment human capability, etc. Across these vastly different areas, the most pressing challenge has to find the artificial muscles, or soft actuators, to power these devices. Past approaches in the field have limitations due to complex operation (e.g., fluidic actuators need to be driven by pumps, and directed by valves), slow response speed (e.g., ionic polymer-metal composites are diffusion limited, making them significant slower than natural muscles), and low energy efficiency (e.g., in a shape memory alloy most of the input electrical energy is lost as heat to the environment, and not used to trigger the phase change). The proposed research program will develop the next generation of artificial muscles, based on dielectric elastomer actuators (DEAs), compliant capacitors that undergo mechanical deformation when an electric field is applied between two stretchable electrodes. Compared to other technologies, DEAs are soft (for multilayer DEAs without a frame), driven by only an electrical input, and as strong and fast as most natural muscles. The proposed research programs borrows concepts from areas in which I have previous expertise, including electrochemistry, materials science, and folding origami structures. DEAs are most often characterized from a mechanical standpoint, evaluating the force output and displacement, at different actuation frequencies, without evaluating the corresponding electrical properties. My research group will study the electrical behavior of DEAs during actuation, similar to how batteries are characterized by repeated charge / discharge cycles. Using this approach we will have an unprecedented look at the interplay between electrical and mechanical stress in the long term behavior of DEAs. Similarly, DEA failure is generally attributed to the behavior of the elastomer, without close examination of the electrode or the elastomer-electrode interface. With ultra-thin electrodes and novel characterization techniques, we will link material microstructure to device performance. Lastly, DEAs are often operated within a relatively rigid frame, which limits the range of motion and makes robot integration challenging. By expanding upon novel 2D fabrication techniques, my group will build composite structures with embedded actuators for the next generation of soft robotics. The research program is rooted in Mechanical Engineering, using novel tools and processes to set new standards for how artificial muscles are manufactured, evaluated, and integrated into smart devices and robotics. When completed, the program will find applications in a range of fields where humans and robots interact, including collaborative manufacturing, artificial limbs, tactile communication devices, and beyond.