To mimic the spatial figure-of-eight trajectory of insect wing tips

a flapping wing mechanism based on spatial revolute-universal-revolute-spherical (RURS) four-bar linkage was designed to enable output of the three-dimensional spatial figure-of-eight trajectory with one input. Denavit-Hartenberg parameters method was used to establish the kinematic model of the spatial four-bar mechanism. Based on the genetic algorithm

the optimal parameters of linkages facilitating the flapping wing flight were acquired. A micro air vehicle virtual prototype was designed based on the optimal spatial four-bar linkage

meanwhile

the result of kinematic model was verified by ADAMS prototype simulation. The flapping amplitude of the flapping wing mechanism was 149.8°

and the twist angle was 29.9°

meanwhile the designed figure-of-eight flapping pattern was similar to insects in nature. The maximum size of the flapping wing mechanism was no more than 5.8cm

and the time asymmetric flapping pattern found from the simulation results can improve the aerodynamic performance to a certain extent

providing valuable insight weight to design light weight and efficient micro-air-vehicles.