Design and Development of a Contact-Aided Compliant Flapping Wing for Micro Air Vehicle

In this paper, a contact-aided compliant flapping wing for micro air vehicle (MAV) is presented. The design consists of a perforated plate, covered with flaps which allow motion in one direction only. In order to arrest the motion of flaps in the other direction, a contact stopper is provided. When the wing (i.e., perforated plate along with flaps) is making a flapping motion in a fluid environment, it experiences different drag forces in forward and reverse strokes. The wing is made with acrylic (Poly (methyl methacrylate) or PMMA) sheet having 2 mm thick. The flaps are connected to perforated plate by compliant joints that act as torsional springs. Furthermore, these compliant joints aid in moving flaps from open to a closed position. Experiments were carried out in both air and water medium for various plate configurations. It is observed that only 14.71% of input power is saved during a reverse stroke of four-flap perforated plate while flapping in air. Hence, the advantage is less in air, wing thickness needs to be reduced substantially to get an advantage in air medium. But in a water medium, input power is saved by 32.80% for the current dimensions. This increment is due to the fact that the density of water is more compared to air. It is also noticed that there is no advantage beyond 65 and 70% of area reduction in air and water mediums respectively as it is the minimum power required to drive the servomotor.