Experimental Studies Towards Understanding the Aeromechanics of a Flexible Robotic Hummingbird Wing in Hover

This study investigated the aeroelastic mechanics of a flexible flapping wing designed and implemented on a two-winged, flapping wing, robotic hummingbird capable of hovering. The investigation focused first on measuring aerodynamic and inertial forces and using these results to quantify efficiency; second, on measuring vertical inertial forces on the flexible flapping wing for the first time using Digital Image Correlation; and three, on quantifying the flowfield using Particle Image Velocimetry at the 70% spanwise location of the wing. The purpose of these experiments was to optimize the lift generation and increase the efficiency of the hover-capable robotic hummingbird. A bench-top experimental setup was designed and developed which flapped a duplicate of the wing used in the actual flying vehicle, and utilized the same flapping kinematics. This setup allowed for the variation of flapping parameters, as well as measurement of performance metrics through sensors which measured the instantaneous lift, torque, flap angle, and current draw. The results found that 108° flapping amplitude at 20 Hz was the most power efficient. This is the first time instantaneous vertical force and torque measurements have been successfully conducted on a flexible, hover capable flapping wing used on a flying vehicle. Additionally, this study calculates vertical inertial loads for the same type of wing using deflection measurements. Results from this investigation can be used for further refinement and structural tuning of flexible flapping wing design for hovering flight

Experimental Studies Towards Understanding the Aeromechanics of a Flexible Robotic Hummingbird Wing in Hover

This study investigated the aeroelastic mechanics of a flexible flapping wing designed and implemented on a two-winged, flapping wing, robotic hummingbird capable of hovering. The investigation focused first on measuring aerodynamic and inertial forces and using these results to quantify efficiency; second, on measuring vertical inertial forces on the flexible flapping wing for the first time using Digital Image Correlation; and three, on quantifying the flowfield using Particle Image Velocimetry at the 70% spanwise location of the wing. The purpose of these experiments was to optimize the lift generation and increase the efficiency of the hover-capable robotic hummingbird. A bench-top experimental setup was designed and developed which flapped a duplicate of the wing used in the actual flying vehicle, and utilized the same flapping kinematics. This setup allowed for the variation of flapping parameters, as well as measurement of performance metrics through sensors which measured the instantaneous lift, torque, flap angle, and current draw. The results found that 108° flapping amplitude at 20 Hz was the most power efficient. This is the first time instantaneous vertical force and torque measurements have been successfully conducted on a flexible, hover capable flapping wing used on a flying vehicle. Additionally, this study calculates vertical inertial loads for the same type of wing using deflection measurements. Results from this investigation can be used for further refinement and structural tuning of flexible flapping wing design for hovering flight