Bats have a unique flying style that allows them to be highly dexterous in capturing prey and have great freedom of movement in flight. Bats' wings have a wing membrane that is tensioned by their fingers and arms, allowing them to retract their wings laterally in flight. This distinct motion has allowed bats to be the only mammals capable of sustained flight, adding to their evolutionary uniqueness. This thesis presents the creation of the VALKRIE (Versatile Aerial Lifesize Kinetic Robot Inspired by bat Evolution) project: a to-scale simplified bat-inspired ornithopter that can be remotely controlled, sustain flight, and passively retract and extend its wings laterally. VALKRIE mimics the dimensions and size of its biological counterpart, Hipposideros diadema, a medium-sized bat; setting its aerodynamical constraints to the dimensions of Hipposideros diadema. Bats' maneuverability is derived from their unique wing motion while in flight, retracting and extending their wings. VALKRIE mimics this motion by simplifying the joint structure of a bat's wing and passively retracting and extending the wings. By simplifying the complex anatomy of bat wing motion, VALKRIE can maintain flight and generate sufficient lift for increasing altitude. With a simplified design, VALKRIE only has two motors that actuate wing flapping, wing retraction, and rotation of the hind legs. With this simplified design, the operator can remotely control VALKRIE by increasing and decreasing the wingbeat frequency and steering to the right and left with the hind legs. / Master of Science / Bats have a unique flying style that allows them to be highly dexterous in capturing prey and have great freedom of movement in flight. Bats' wings have a wing membrane that is tensioned by their fingers and arms, allowing them to retract their wings laterally in flight. This distinct motion has allowed bats to be the only mammals capable of sustained flight, adding to their evolutionary uniqueness. This thesis presents the creation of the VALKRIE (Versatile Aerial Lifesize Kinetic Robot Inspired by bat Evolution) project: a to-scale simplified bat-inspired ornithopter that can be remotely controlled, sustain flight, and passively retract and extend its wings laterally. VALKRIE mimics the dimensions and size of its biological counterpart, Hipposideros diadema, a medium-sized bat; setting its aerodynamical constraints to the dimensions of Hipposideros diadema. Bats' maneuverability is derived from their unique wing motion while in flight, retracting and extending their wings. VALKRIE mimics this motion by simplifying the joint structure of a bat's wing and passively retracting and extending the wings. By simplifying the complex anatomy of bat wing motion, VALKRIE can maintain flight and generate sufficient lift for increasing altitude. With a simplified design, VALKRIE only has two motors that actuate wing flapping, wing retraction, and rotation of the hind legs. With this simplified design, the operator can remotely control VALKRIE by increasing and decreasing the wingbeat frequency and steering to the right and left with the hind legs.

The objective of this work was to develop an analysis framework for the structural design of the Human-Powered Ornithopter (HPO). This framework was used in a kinematicaerostructural optimizer for apping-wing ight (Ornithia), as well as analytically to design the HPO, and focused on three goals. First was the development of an accurate and computationally inexpensive nite-element method, to be integrated with Ornithia, which would capture the geometric nonlinearity of the aerostructural interaction of the wing when subjected the large deformations in ight. Second was the assembly of a model by which the aircraft primary structure, the wing main spar especially, could be exactly characterized and designed. Third was the establishment of a process and toolbox for failure analysis which could be applied universally in the design of the HPO. The validation and tuning of these models involved extensive testing on prototype carbon ber composite components.

The objective of this work was to develop an analysis framework for the structural design of the Human-Powered Ornithopter (HPO). This framework was used in a kinematicaerostructural optimizer for apping-wing ight (Ornithia), as well as analytically to design the HPO, and focused on three goals. First was the development of an accurate and computationally inexpensive nite-element method, to be integrated with Ornithia, which would capture the geometric nonlinearity of the aerostructural interaction of the wing when subjected the large deformations in ight. Second was the assembly of a model by which the aircraft primary structure, the wing main spar especially, could be exactly characterized and designed. Third was the establishment of a process and toolbox for failure analysis which could be applied universally in the design of the HPO. The validation and tuning of these models involved extensive testing on prototype carbon ber composite components.

Birds and bats employ a variety of advanced wing motions in the efficient production of thrust. The purpose of this thesis is to quantify the benefit of these advanced wing motions, determine the optimal theoretical wing kinematics for a given flight condition, and to develop a methodology for applying the results in the optimal design of flapping-wing aircraft (ornithopters). To this end, a medium-fidelity, combined aero-structural model has been developed that is capable of simulating the advanced kinematics seen in bird flight, as well as the highly non-linear structural deformations typical of high-aspect ratio wings. Five unique methods of thrust production observed in natural species have been isolated, quantified and thoroughly investigated for their dependence on Reynolds number, airfoil selection, frequency, amplitude and relative phasing. A gradient-based optimization algorithm has been employed to determined the wing kinematics that result in the minimum required power for a generalized aircraft or species in any given flight condition. In addition to the theoretical work, with the help of an extended team, the methodology was applied to the design and construction of the world's first successful human-powered ornithopter. The Snowbird Human-Powered Ornithopter, is used as an example aircraft to show how additional design constraints can pose limits on the optimal kinematics. The results show significant trends that give insight into the kinematic operation of natural species. The general result is that additional complexity, whether it be larger twisting deformations or advanced wing-folding mechanisms, allows for the possibility of more efficient flight. At its theoretical optimum, the efficiency of flapping-wings exceeds that of current rotors and propellers, although these efficiencies are quite difficult to achieve in practice.

Birds and bats employ a variety of advanced wing motions in the efficient production of thrust. The purpose of this thesis is to quantify the benefit of these advanced wing motions, determine the optimal theoretical wing kinematics for a given flight condition, and to develop a methodology for applying the results in the optimal design of flapping-wing aircraft (ornithopters). To this end, a medium-fidelity, combined aero-structural model has been developed that is capable of simulating the advanced kinematics seen in bird flight, as well as the highly non-linear structural deformations typical of high-aspect ratio wings. Five unique methods of thrust production observed in natural species have been isolated, quantified and thoroughly investigated for their dependence on Reynolds number, airfoil selection, frequency, amplitude and relative phasing. A gradient-based optimization algorithm has been employed to determined the wing kinematics that result in the minimum required power for a generalized aircraft or species in any given flight condition. In addition to the theoretical work, with the help of an extended team, the methodology was applied to the design and construction of the world's first successful human-powered ornithopter. The Snowbird Human-Powered Ornithopter, is used as an example aircraft to show how additional design constraints can pose limits on the optimal kinematics. The results show significant trends that give insight into the kinematic operation of natural species. The general result is that additional complexity, whether it be larger twisting deformations or advanced wing-folding mechanisms, allows for the possibility of more efficient flight. At its theoretical optimum, the efficiency of flapping-wings exceeds that of current rotors and propellers, although these efficiencies are quite difficult to achieve in practice.