Optimization of lift force for a bio-inspired flapping wing model in hovering flight

Abstract

The lift force is an important component that affects the aerodynamic performance of bio-inspired flapping-wing micro aerial vehicles. However, there is a lack of endeavors in the optimization of the flapping wing parameters that affect the lift force of micro aerial vehicles. This research is therefore to establish a methodology that combines computational fluid dynamic simulation for the evaluation of the lift generation and wing parameters. The Taguchi's framework for design of experiments, combined with the computational fluid dynamics simulations, is performed on a simplified robotic fly wing model used in the experiment found in Dickinson et al. (1999), under the hovering flight mode, to identify the most influential parameters on the lift generation of micro aerial vehicles. A commercial computational fluid dynamics code, ANSYS/FLUENT, along with a three-dimensional Navier-Stokes solver is used to simulate the unsteady flow field. With the optimization of the time-averaged lift force as the optimization objective, five typical parameters (flapping frequency, maximum angle of attacks during the upstroke and downstroke motions, stroke amplitude, and rotation type) in the flapping trajectory equation are selected as the input factors with each having four levels. Specific computational fluid dynamics cases are simulated in accordance with the chosen orthogonal arrays. By conducting statistical analyses with analyses of means and variance, the flapping frequency and the stroke amplitude are determined to be the two most influential parameters. The response surface of the time-averaged lift force and the power consumption contour are constructed with respect to these two parameters to determine the optimal combination for the generation of lift forces under a specific power constrain and provide a guideline for bio-inspired micro aerial vehicle designs.