A functional assessment of hand flapping exhibited by a 5-year-old boy was conducted in a general education classroom. After a descriptive analysis ruled out several potential variables maintaining hand flapping, an experimental analysis was used to test the hypothesis that teacher-delivered task demands were functionally related to hand flapping. Results of the experimental analysis were used ...

We present a new mechanism for passive wing morphing of flapping wings inspired by bat and bird wing morphology. The mechanism consists of an unactuated hand wing connected to the arm wing with a wrist joint. Flapping motion generates centrifugal accelerations in the hand wing, forcing it to unfold passively. Using a robotic model in hover, we made kinematic measurements of unfolding kinematics...

I nsects and hummingbirds remain unmatched in their aerodynamic ability to hover in place in addition to other acrobatic feats such as flying backward and sideways by exploiting flapping-wing motion [1]. Although this remarkable ability is key to making small-scale aircraft, flapping-hovering behavior has been difficult to reproduce artificially because of the challenging stability, power, and ...

Basal birds such as Archaeopteryx and Confuciusornis are typically portrayed as flapping fliers. However, here I show that shoulder joint orientation in these animals prevented elevation of the humerus above the dorsum, thereby preventing use of the recovery stroke, an important part of flapping flight. In members of the clade Ornithothoraces, which includes extant birds and the extinct avian c...

Thrust generation by flapping is accompanied by alternating pitching moment. On the down-stroke, it pitches the bird down when the wings are above its centre of gravity and up when they are below; on the up-stroke, the directions reverse. Because the thrust depends not only on the flapping characteristics but also on the angle of attack of the bird's body, interaction between the flapping and b...

It is well-known that insects utilize vortices generated by flapping, by which they generate larger lift than that evaluated by the ordinary aerodynamic theory. However, the relative position between the vortices and the wing is affected by the motion of the center of gravity(CG). Such effect has not been well understood. To clarify the effect, we numerically analyzed a simple model considering...

Flapping flight is more maneuverable than steady flight. It is debated whether this advantage is necessarily accompanied by a trade-off in the flight efficiency. Here we ask if any flapping motion exists that is aerodynamically more efficient than the optimal steady motion. We solve the Navier-Stokes equation governing the fluid dynamics around a 2D flapping wing, and determine the minimal aero...

A three-dimensional high-order unstructured dynamic grid based spectral difference (SD) Navier-Stokes (N-S) compressible flow solver with low Mach number preconditioning is used to investigate the effects of wing planforms on the aerodynamics performance of the thin finite-span flapping wings in this paper. Two types of wings, namely the rectangular and bio-inspired wings, are simulated and com...

Flapping-wing robotic platforms based on Dipteran insects have demonstrated lift to weight ratios greater than 1, but research into regulating the aerodynamic forces produced by their wings has largely focused on active wing trajectory control. In an alternate approach, a flapping-wing drivetrain design that passively balances aerodynamic drag torques is presented. A discussion of the dynamic p...

Many flying animals use both flapping and gliding flight as part of their routine behaviour. These two kinematic patterns impose conflicting requirements on wing design for aerodynamic efficiency and, in the absence of extreme morphing, wings cannot be optimised for both flight modes. In gliding flight, the wing experiences uniform incident flow and the optimal shape is a high aspect ratio wing...