An investigation into an adaptable morphing concept for enhancing aircraft control and performance is described in this thesis. The impetus for the work was multi-legend. Initially, the work involved identifying and optimizing winglets on a swept wing baseline configuration to enhance the controllability and aerodynamic efficiency of unmanned aerial vehicles. Moreover, the other objective was to develop a realistic skin for a morphing aircraft concept that would allow subtle, more efficient shape changes to improve aircraft efficiency. In this regard, preliminary computations were performed with Athena Vortex Lattice modelling in which varying degrees of twist, swept and dihedral angle were considered. The results from this work indicated that if adaptable winglets were employed on small scale UAVs improvements in both aircraft control and performance could be achieved. Subsequent to this computational study, novel morphing wing and/or winglet mechanisms were developed to provide efficient shape changing as well as to develop a novel alternative method for a morphing skin. This new technique was numerically optimized in ANSYS Mechanical, experimentally investigated in a wind tunnel, and also compared with a baseline aileron configuration. Afterwards, flight testing was performed with an Extra 300 78 inch remote controller aircraft with the results being compared against existing fixed wing configurations. After evaluating numerical results, from various winglet configurations investigated in AVL, selected cases were found to provide good evidence that adaptable winglets, through morphing, could provide benefits for small scale aircraft control and performance as well as offering an acceptable alternative aircraft control methodology to the current discrete, 3-axis control philosophies. Using ANSYS Mechanical for structural analysis, rib configurations were also optimised in terms of weight, stress, and displacement, as well as required twist deformation magnitudes (±6° of twist achieved). Furthermore, the skin was found to be rigid with a low rate of surface wrinkling promoting a low drag surface. Ultimately, the viability of this novel concept mechanism was validated through flight testing with similar roll authority achieved compared to traditional aileron configuration. Finally, a morphing concept also provided potential shape changing performance with smooth aerodynamic surface finish. Leading to the possibility of the concept is being a viable skin for morphing application.

Small scale unmanned aircraft, such as quadrotors, that are quickly emerging as versatile tools for a wide range of applications including search and rescue, hazardous environment exploration, or just shooting great video, are known as micro air vehicles (MAVs). However, for millimeter scale vehicles with weights under 10 grams, conventional flight technologies become greatly inefficient and instead inspiration is drawn from biology. Flapping wing MAVs (FWMAVs) have been created based on insects and hummingbirds in an effort to emulate their extreme agility and ability to hover in place. FWMAVs possess unique capabilities in terms of maneuverability, small size, and ability to operate in dynamic environments that make them particularly well suited for environmental monitoring and swarm applications such as artificial crop pollination. Despite their advantages, significant challenges in fabrication, power, and control must be overcome in order to make FWMAVs a reliable platform. Current designs suffer from high mechanical complexity and often rely on off-board power, sensing, and control, which compromises their autonomy and limits practical applications. The goal of my research is to develop a simple FWMAV design that provides high efficiency and controllability. An efficient, simple, and controllable vehicle design is developed utilizing the principles of resonance, emulation of biological flight control, and under-actuation. A highly efficient, resonant actuator is achieved by attaching a spring in parallel to the output shaft of a commercial geared DC micro-motor. This actuator directly drives the wings of the vehicle, allowing them to be controlled precisely and independently. This direct control strategy emulates biology and differs from other FWMAV designs that utilize complicated transmissions to generate flapping from rotary motor output. Direct control of the wings allows for emulation of biological wing kinematics, resulting in control based on wing motion alone. Furthermore, under-actuation is employed to mimic the rotational motion of insect wings. A rotational joint is added between the motor and wing membrane such that the wing rotates passively in response to aerodynamic forces that are generated as the wing is driven. This design is realized in several stages, initial prototyping, simulation and development of the actuator and wings, then finally a control system is developed. First the system was modeled and improved experimentally in order to achieve lift off. Improvements to the actuator were realized through component variation and custom fabrication increasing torque and power density by 161.1% and 666.8% respectively compared to the gearmotor alone and increased the resonant operating frequency of the vehicle from 4 Hz to 23 Hz. Advances in wing fabrication allowed for flexible wings that increased translational lift production by 35.3%, aerodynamic efficiency by 41.3%, and the effective lift coefficient by 63.7% with dynamic twisting. A robust control architecture was then developed iteratively based on a date driven system model in order to increase flight time from 1 second (10 wing strokes) to over 10 seconds (230 wing strokes). The resulting design improves lift to weight by 166%, allowing for a payload capacity of approximately 8.7 g and offers the potential for fully autonomous operation with all necessary components included on-board. A thermal model for micro-motors was developed and tuned to accurately predict an upper limit of system operation of 41 seconds as well as to optimize a heatsink that increases operating time by 102.4%.