Abstract
The insect obtains driving force and lift force by flapping. The dragonfly changes its flapping state of four pieces of wings according to flight conditions. The wing performance of the robot dragonfly which was able to fly was measured in order to grasp its flight states. The wing performances with the three configurations of the fore and the hind wings were compared in two conditions, steady and unsteady. One of the configurations was the state when the fore and the hind wings flapped synchronously seen in a taking off and landing and turning state phase. The others were the states when the fore and the hind wings alternatively flapped seen in a cruise state. The phase difference in the flapping of the hind wing advancing to that of the fore wing is 90° and 180°. The followings were obtained by these experiments: Free flight conditions of the mechanical dragonfly were realized by wind tunnel measurements. Higher lift force by flapping compared with steady state was confirmed as unsteady lift. Lift force exceeding the body weight was obtained in flapping phase angles of the hind wing advancing for the forewing at the time of 0° and 90 °.
