Aerodynamic modeling of a flexible flapping-wing micro-air vehicle in the bond graph environment with the aim of assessing the lateral control power

Abstract

In this paper, an integrated and systematic modeling of all components and subsystems of a flapping bird robot is developed using the bond graph method. The wings kinematic is independently implemented with the aim of evaluating lateral movements of the bird and aerodynamic forces are accurately extracted by assuming quasi-steady theory. In the present dynamic model, the aeroelastic bending behavior of flexible wing of the flapping bird is revealed by the bond graph method. In this regard, three elastic bending modes and one rigid motion mode of the wing are added to the model. In the following, the performance evaluation of the flapping bird and parametric study are carried out around important quantities such as frequency, initial incidence angle, torsional stiffness, and flapping amplitude of the wings, which results in applicable and attractive consequences. As an innovation, the initial classification and presentation of the comparative characteristic curves for generating lateral forces without using an additional control surface and only based on asymmetry in the flapping kinematic using the bond graph approach is done, which is essential to perform lateral-directional maneuvers. Some important correlations are achieved, which are presented in detail in the text. As an example, the relation between lateral force and phase difference between wings is quasi-linear in a variety of velocities. Therefore, this parameter can be used as input in design of lateral control system. On the other hand, the sensitivity of the lateral force to active pitch angle is more than other quantities; as a result, such mechanism can be effectively used in rapid maneuvers. Finally, based on the presented bond graph model, it would be easily possible to study the effects of design variables, mechanical properties, geometric constraints, and specially flapping kinematics on a wide range of functional and performance indices.