3D Printing functional structures for flapping wing aerial robotics

Flapping flight is one of the wonders of nature. The state-of-the-art of bioinspired aerial robots still has to bridge a big gap, where energy efficiency, multi-modal operation and complex environments pose challenges due to a lack of functionality and autonomy. By drawing inspiration from distributed sensing and actuation in nature, the shortcomings of current bio-inspired aerial robots can be mitigated by means of embedding flow sensing, proprioception and variable stiffness. This can be achieved through embedding of functional materials and structures through 3D printing. With the advent of 3D printing it has become possible to generate new multi-material structures over multiple
orders of magnitude in scale, enabling complex geometries, embedded electronics or composites in a single fabrication step. Especially Fused Filament Fabrication (FFF) is widely preferred due to its simple, low cost, multi-material capabilities. This technique has been used for 3D printing sensors and robotics, where conductive polymer composites can be used as smart materials due to their electro-thermo-mechanical properties. Using these materials, FFF introduces anisotropic physical properties in 3D prints due to the line-by-line, layer-per-layer printing process.
The first goal of this thesis is to investigate how the specific properties of 3D printed functional materials can be exploited, i.e. anisotropic electrical resistivity, that are otherwise hard to obtain and tailor. The second goal is to study how stiffness modulation, deformation sensing and flow sensing can be implemented in 3D printed flapping flight robots with functional materials.
Overall the electrical anisotropy in 3D prints is clearly modeled, measured and tailored in fabrication, and it is shown how it can be used or reduced in sensor applications. Promising sensing and variable stiffness ideas for implementation in a robotic bird have been presented, where future research can close the gap between the lab and implementation in aerial robots.