A bio-inspired flapping wing robot with twist and fold capability

Bat flight is characterized by complex wing motions. Here we present results obtained using a three degrees of freedom flapping wing robotic platform. In addition to the up/down wing flapping motion, the model can perform hand/armwing folding and wing twisting along the span of the handwing. Using this platform, we explore numerous unsteady aerodynamic effects, including handwing clapping during the upstroke, as observed in fast forward flight of the frugivorous bat, Cynopterus Brachyotis, as well as the generation of rotational lift due to rapid wing pronation during the up/downstroke transition when folding is also present – a synergy between twist and fold motions. We record aerodynamic forces and moments of the flapping wing model placed in a wind tunnel at several flight speeds, and compare the results with quasi-steady numerical models based on blade element theory. If time permits, we will present PIV measurements of the flows generated by the flapping wing with these complex kinematic wing motions.