Structural Design and Aerodynamic Characteristics of Two Types of Fold-Able Flapping-Wings

Abstract

Large wingspan birds inspire the studies about the bionic fold-able flapping-wing robot. To explore the influencing factors of the bionic ornithopter’s aerodynamic characteristics, two bionic fold-able flapping-wing flapping mechanisms were established to simulate the flight motion of birds. We present two fold-able flapping-wing structural design methods with parameters: inner wing flapping and outer wing folding angles. A simulation analysis is carried out for these structures based on XFlow, and the influence on lift and thrust is explored with different flapping frequencies and air velocities. The results show that the lift and drag of the ornithopter increase with air velocity, and the thrust increases with the rise of flapping frequency. Furthermore, the comparisons indicate that an asymmetric flapping mode of fold-able wing structure has better aerodynamic characteristics. The critical contribution of this paper is that we propose helpful structural design guidance for flapping-wing robots.