Effects of motion-induced aerodynamic force on the performance of active buffeting control

Abstract

During buffeting control of an aircraft, there consequently is a motion-induced aerodynamic force. However, it is not yet clear whether this additional force must be considered in design of control law. In this paper, to hopefully answer this interesting question, effects of the motion-induced aerodynamic force on the active buffeting control during control law design are studied. The macro fiber composite (MFC) actuator is modeled by employing the load simulation method, and the motion-induced unsteady aerodynamic forces are computed by the doublet-lattice method. Two different controllers, i.e. one with the motion-induced aerodynamic force and another without it, are simultaneously designed based on the linear quadratic Gaussian (LQG) control method. And, two corresponding models are respectively developed. Then, the control effects of the two models are compared and the physical mechanisms are discussed. From our simulation results it is found that the motion-induced aerodynamic forces do influence the buffeting responses depending on airflow velocity. The differences of the control effects of the two models are smaller at lower airflow velocity below the flutter velocity, however with the increase of the airflow velocity the control effect of the model considering the motion-induced aerodynamic force is much better. The larger the velocity is, the more significant the differences are. Finally, the energy dissipation of the motion-induced aerodynamic force is examined and found to be a main factor influencing the differences of the two models.