Research on long periodical structural deformation of flexible flapping wing in flight

Through observation and analysis of flight test of DOVE flapping MAV[1], long periodical plunging movement has been observed during flight, accompanied with which is short periodical plunging movement that caused by flapping movements. Since of constant driving input, this special phenomenon could be aroused by the intrinsic characters of structure, such as natural frequency. This special feature can obviously influence the flight quality and increase the difficulties of control. Hence, it is necessary to investigate this phenomenon, which has been studied through computational method in this paper. In order to obtain accurate Finite Element model, many properties of flapping wing including elastic modulus and natural frequencies have been tested and measured. The correlation between flapping frequency and deformation history of flapping wing has been concluded that specific flapping frequency would exacerbate long periodical effect, such as frequency is 6 Hz. The reason behind this phenomenon is proposed and proved.