AILERON AND SIDESLIP-INDUCED UNSTEADY AERODYNAMIC MODELING FOR LATERAL PARAMETER-ESTIMATION

Aileron inputs and sideslipping motion of an aircraft will give rise t o a trailing vortex system that is a function of time. To account for such unsteady aerodynamic effects into the lateral equations of motion , a model is proposed based on a simple vortex system. The expressions for induced sidewash and downwash angles obtained for such vortex sys tem are recast so that the resulting equations of motion can be used f or parameter estimation. Maximum likelihood method in frequency domain is used to analyze simulated flight data of an example airplane to st udy the effects of inclusion and omission of unsteady aerodynamic mode ling on estimated parameters. Sensitivity of the extracted parameters to different control input forms is shown to reduce with the inclusion of unsteady aerodynamics.