Evaluation of Recursive Least Squares algorithm for parameter estimation in aircraft real time applications

This paper presents results of evaluation of Recursive Least Squares (RLS) algorithm for real time applications in flight control and testing. The RLS proposed here is based on the equation error principle and can start with zero values of the unknown parameters. The technique makes use of only forgetting factor and a stabilizing parameter to achieve better convergence characteristics. In the present study, the RLS technique is applied for parameter estimation in the context of (i) reconfigurable/restructurable control, (ii) estimation of aircraft short period and Dutch roll characteristics in the absence of calibrated air data, and (iii) online stability (gain and phase) margin estimation.