Global aircraft aero-propulsive linear parameter-varying model using design of experiments

In this paper, applicability of modeling global aircraft aerodynamic-propulsive coefficients using a design of experiments technique based on a linear parameter-varying model is investigated. The proposed technique consists of a local estimation phase and a global identification phase. For the local estimation phase, a set of multiple orthogonal phase-optimized multi-sine inputs (elevator, aileron, rudder, and throttle) is executed at different locations over the operational flight envelope. The resultant aircraft responses are used to estimate the equivalent stability and control derivatives at each flight condition. Design of experiments is then employed to globally identify the stability and control derivative variations with velocity, altitude, aircraft mass, and center of gravity position. A sequential experiment using a factorial design and augmented face central axial points was employed to model the variation. For demonstrating technique feasibility, a nonlinear simulator for an F-16 was used to assess the proposed approach. The validity of the proposed method was evaluated by comparing the aircraft response based on the proposed aerodynamic-propulsive model with the actual model. The proposed technique has the capability to deliver a model for a computationally complex and large envelope aerodynamic-propulsive airframe system.