Nonlinear Time-Domain System Identification of Aircraft Stability and Control Derivatives

This paper presents a nonlinear time-domain system identification method to estimate the stability derivatives for NASA-Boeing Transonic Truss-Braced Wing configuration. Nonlinear aerodynamics in large-amplitude forced oscillations can cause significant frequency interactions with the linear response at the input frequency. This is called a nonlinear spillover effect. In our previous work, nonlinear frequency-domain methods have been developed for estimation of stability and control derivatives. In this work, we are proposing to develop a nonlinear time-domain system identification method using a recursive least-squares technique. The proposed method is applied to compute the linear and nonlinear stability derivatives of the Transonic Truss-Braced Wing.