Low-Order Modeling of Flapping Flight with Highly Articulated, Cambered, Heavy Wings

Abstract

A three-dimensional low-order modeling technique is described for modeling both wing inertial and aerodynamic forces of animals and robots flapping heavy and morphing wings. The model is applied to prescribed kinematics from a previously measured flight of a lesser-nosed, dog-faced fruit bat (Cynopterus brachyotis) in straight and climbing flight. Quasi-steady blade element momentum theory is used to model the aerodynamic forces of the highly articulated wing, and a Lagrangian equation of motion is adopted to describe the overall wing–body dynamics that includes the wing inertia. These two distinct and independent models yield a good prediction of the thrust/drag balance, and are in excellent agreement of lift production. Unique to this approach, the quantitative effect of wing camber was examined within the framework, which contributes as much as 27% of the cycle-averaged lift, with a smaller price (10%) paid to drag.