Design and evaluation of a LIPCA-actuated flapping device

In this paper, we have introduced a flapping wing mechanism actuated by a unimorph piezoceramic actuator, LIPCA (lightweight piezo-composite actuator). In the flapping system, the limited actuation displacement produced by bending motion of the simply supported actuator was transformed into a large flapping angle by using a four-bar linkage system. A wing rotation mechanism was also designed and implemented such that the wing can be passively rotated due to the resultant aerodynamic force during flapping motion. The natural flapping frequency of the device was about 9 Hz, where the maximum flapping angle was achieved. Flapping tests under 4–15 Hz flapping frequencies were performed to investigate the flapping performance by measuring the vertical force and forward force produced. The maximum forces were produced when the flapping device was actuated near the natural flapping frequency. The measured force data indicated that the present flapping system could produce positive average forces in the vertical and forward directions.