Ornithopters, or flapping-wing aircraft, offer an alternative to helicopters in achieving manoeuvrability at small scales, although stabilizing such aerial vehicles remains a key challenge. Here, we present a hovering machine that achieves self-righting flight using flapping wings alone, without relying on additional aerodynamic surfaces and without feedback control. We design, construct and te...

Optimal thickness distributions of aeroelastic flapping shells" (2013). a r t i c l e i n f o a b s t r a c t The severe weight limitations of flapping wing micro air vehicles necessitates the use of thin flexible wings, which in turn requires an aeroelastic modeling tool for proper numerical characterization. Furthermore, due to the unconventional nature of these vehicles, wing design guidelin...

The science of animal flight requires the quantification of wing movement over a range of behaviors. Despite numerous studies of avian locomotion, we are only beginning to grasp the intricacies of flapping flight. Birds create aerodynamic forces by manipulating the fluid environment of air by beating their wings. The question remains, how do they perform such a wide range of locomotor behaviors...

An experimental investigation was performed with two aims: (1) to clarify the existence of the dual leading-edge vortices (i.e. two vortices with the same sense of rotation located close to the leading edge above the leeward wing surface) observed on flapping wings in previous studies; (2) to study systematically the influences of kinematic and geometric parameters on such a vortical structure....

Recently, flapping robots are noticed by many researchers, and many challenges are being made toward the realization of flight motions like insects, birds and so on. The purpose of this work is to develop flapping robots using a new type of piezoelectric material, that is, piezoelectric fiber composites. By using the composites, actuating fibers and sensing fibers can be embedded into a wing as...

The optimization of a controlled flapping wing micro aerial vehicle for energy-efficient flight in gust using a general, service-oriented framework is investigated. Kinematic (wing-stroke pattern), geometric (wing shape), frequency, and control (state penalty) design variables are considered in a sequence of optimization problems. The service-oriented framework is applied to the integration of ...

While the wing kinematics of many flapping insects have been well characterized, understanding the underlying sensory, neural, and physiological mechanisms that determine these kinematics is still a challenge. Two main difficulties in understanding the physiological mechanisms arise from the complexity of the interaction between a flapping wing and its own unsteady flow, as well as the intricat...

Developing animals are particularly vulnerable to predation. Hence, precocial young of many taxa develop predator escape performance that rivals that of adults. Ontogenetically unique among vertebrates, birds transition from hind limb to forelimb dependence for escape behaviours, so developmental investment for immediate gains in running performance may impair flight performance later. Here, in...

The unsteady low Reynolds number aerodynamics of flapping flight was investigated experimentally through flow visualization by suspended particle imagery and wall shear stress measurement from micro-array hot-film anemometry. In conjunction, a mechanism was developed to create a flapping motion with three degrees of freedom and adjustable flapping frequency. The flapping kinematics and wing sha...