Designing Light-material Interactions for Soft Robotics
Soft robotics represents a shift in engineering design methodology: one that draws inspiration from biology and strives to move away from complex, rigid assemblies of numerous discrete parts and towards soft assemblies comprised of relatively few parts. Proponents of this shift advocate that soft robots will enable safe operation around humans, increased resistance to mechanical damage, operation in hazardous environments, and other functions that are presently inaccessible via traditional (i.e., rigid) robotics. However, bringing these visions to life requires efficient energy systems, soft controllers, and new material systems. This dissertation is an exploration of the myriad ways that light-material interactions can be leveraged to offer innovations in each of these areas. Light serves as the common thread among each of these investigations as it is an accessible form of energy that can be modulated (e.g., by wavelength or intensity) and transmitted (e.g., lasers) or harvested (e.g., sunlight) over long distances with highly tunable spatial and temporal precision. First, we examine the capabilities of soft heat engines, identify their major sources of losses and offer three key insights that soft roboticists can leverage to minimize them (Chapter II). Second, we investigate the photokinetics of a novel class of photoswitches, which constitute the basis for a thermofluidic switch (Chapter III). Finally, we investigate the mechanical properties of bio-inspired stiff-soft multi-material composites that exhibit impressive toughness (Chapter IV). These endeavors at the intersection of materials, mechanics, chemistry, and thermodynamics put forth foundational knowledge that advances the field of soft robotics and also inspires new avenues for meeting the growing demand for adaptive and autonomous materials and devices.