A micro air vehicle is a flight system being designed for operation within urban environments. Such vehicles are small and highly agile but often have limited control authority. This paper investigates the use of morphing as an effector to provide control authority. Simple mechanisms for morphing are designed to twist the wings of a 24 in vehicle and to curl the wings of a 12 in vehicle. Flight tests show the morphing is an excellent strategy to command roll maneuvers. The resulting vehicles are relatively easy to fly and consequently are suitable for autopilot design and mission deployment.

Biologically inspired concepts are rapidly expanding the range of aircraft technology. Consideration is given to merging two biologically-inspired concepts, morphing and micro air vehicles, and the resulting flight characteristics are investigated. Specifically, wing shaping is used to morph the membrane wings of a micro air vehicle. The micro air vehicle has poor lateral control because hinges, and consequently ailerons, are difficult to install on a membrane wing. Instead, a set of torque rods, aligned along the wings, are used to twist the membrane and shape the wing. The resulting morphing is shown to provide significant control authority for lateral dynamics. A set of flight tests are undertaken to determine the flight characteristics by commanding pulses and doublets to the control actuation. The vehicle demonstrates excellent roll performance in response to wing shaping. Futhermore, the vehicle demonstrates several types of spin behavior related to combinations of elevator deflection and the wing shaping.

This is the authors' pre-publication version. This paper does not include changes and revisions arising from the peer review and publishing processes. The final definitive copy, which should be used for all referencing,

A class of micro air vehicles uses a flexible membrane wing for weight savings and passive shape adaptation. Such a wing is not amenable to conventional aileron mechanisms for roll control, due to a lack of internal wing structure. Therefore, morphing (in the form of asymmetric twisting) is implemented through the use of a torque-actuated wing structure with thousands of discrete design permutations. A static aeroelastic model of the micro air vehicle is developed and validated to optimize the performance of the torque-actuated wing structure. Objective functions include the steady-state roll rate and the lift-to-drag ratio incurred during such a maneuver. An optimized design is obtained through the use of a genetic algorithm presenting significant improvements in both performance metrics compared with the baseline design.= objective function L=D = lift-to-drag ratio p = roll rate U1 = freestream velocity W = transverse wing displacement x LE = leading-edge coordinate y LE = leading-edge coordinate z LE = leading-edge coordinate C P = differential pressure coefficient = objective function weighting parameter

Morphing, which changes the shape and configuration of an aircraft, is being adopted to expand mission capabilities of aircraft. The introduction of biologically-inspired morphing is particularly attractive in that highly-agile birds present examples of aerodynamically-effective shapes. This paper introduces an aircraft with a multiple-joint design that allows variations in sweep to mimic some shapes observed in birds. These variations are independent on the left and right wings along with on the inboard and outboard sections. The aircraft is designed and analyzed to demonstrate the range of flight dynamics which result from the morphing. In particular, the vehicle is shown to have enhanced turning capabilities and crosswind rejection which are certainly critical metrics for the urban environments in which these aircraft are anticipated to operate.