Understanding Insect-Based Flapping Flight from a Micro Air Vehicle Perspective

摘要

The dependence of the performance of insect-based flapping wings, on a few critical parameters such as the wing shape, stiffness and wing-kinematics was studied using performance measurements. A simplified flapping mechanism was designed and developed to emulate insect wing kinematics. The mechanism was then implemented in a dual wing flapping micro air vehicle (MAV), whose gross weight was approximately 130 grams. Detailed performance measurements were made with three different wings, with the same second moment of area, at different translational angles of attack and for frequencies ranging from 6 to 10 Hz. While wing planform shape and surface finish had negligible effects on the performance, the wing stiffness, weight, and angle of attack caused significant differences. The flexibility of the wing degraded its performance due to large deformations. It was noticed that at a mid-stroke translational angle of attack of 58 degrees, maximum lift was generated by the wing with the elliptical planform. The differences in the performance of the different wings can be attributed to their different stiffnesses instead of planform shape. It is important to note that the wings did not stall until an angle of attack of 58°. Two of these wings were used on the MAV, and together, produced lift equal to 60% of MAV weight. Figure of merit obtained using momentum theory for these flapping wings were in the range of 0.10 - 0.15, which is significantly lower than conventional micro-rotors.