Design and Analysis of a Flapping Wing Mechanism with Asymmetric Frequencies for a Micro Air Vehicle

Abstract

The design and development of flapping wing micro air vehicles is an active research area. In this study, design of a wing flapping mechanism is presented based upon continuously variable transmission systems. This mechanism is capable of generating flapping modes, with different and adjustable frequencies for the two wings of a flapping wing micro air vehicle. There is a provision for introducing or correcting asymmetry in flapping frequency of the two wings while keeping the amplitude fixed. Continuously varying transmission utilizing friction is used to achieve a linear change in asymmetry. The sensitivity of the frequency change mechanism can be tuned to reduce the motion and power requirements. A shift in the location of the center of gravity also occurs simultaneously assisting in roll motion control. The simulation of this dynamic system shows that different flapping frequencies for two wings of a flapping wing micro air vehicle have been achieved. A remarkable feature of this mechanism is the provision of varying the flapping frequency for both the wings with a single actuator during flight which not only reduces the weight of the mechanism but also the power requirements. A prototype has been realized to verify the functionality of this new design concept. Computer codes and commercial software’s were used to simulate kinematic and dynamic results. An aerodynamic analysis of wing profile and parametric study of link lengths has been done. Experimental values for power requirements using the prototype developed were compared with those obtained from analysis based on computer software. Results for the kinematic and dynamic simulations and experimental setup for the mechanism are presented.