On-line system identification for aircraft with distributed control effectors

An algorithm is presented for the identification of aircraft stability deri vatives and distributed control derivatives, in real time. Feedback control correlates the effecters' displacement with the aerodynamic angles, while the most commonly used control allocation algorithms correlate the effecter s. The result is that valid derivative estimation is not possible. This pap er addresses the effector identification problem by including decorrelating excitation into the control allocation cost function while still satisfyin g the desired control moment, and therefore does not introduce any residual perturbations into the motion variables. A two-step identification algorit hm is used where the stability derivative and a generalized control derivat ive are identified in the first step. Results are shown for a stability axi s roll maneuver with the stability and control derivatives being identified for five differential lateral directional effecters. Published in 1999 by John Wiley & Sons, Ltd. This article is a US Government work and is in the public domain in the United States.