A self-designing flight control system (SDFCS) could provide a cost-effective means for developing controllers for new aircraft by eliminating analyst-intensive design of numerous individual controllers, each optimized for a single flight condition. Additionally, the SDFCS could improve the capabilities of existing aircraft by enhancing control performance in new flight regimes such as high angle-of-attack or post-stall maneuvers. Finally, the SDFCS could automatically reconfigure the control system to account for sudden changes such as may result from airframe and/or effector impairment(s).Rapid identification of time-varying, nonlinear plants is an important enabling technology for most SDFCS concepts. In this paper, the authors present a modified sequential least squares (MSLS) parameter identification method and compare its performance to that of standard RLS techniques using a simulated nonlinear F-16 with multiaxes thrust-vectoring (MATV) aircraft. It is shown that MSLS offers significant improvement in performance over conventional RLS parameter identification by providing: (1) a recursive estimation algorithm that penalizes noisy estimates and is less subject to ill-conditioning as its forgetting factor is reduced, (2) detection of airframe and effector impairments and corresponding adjustments of the algorithm settings, and (3) an intelligent supervisor that injects a minimum level of effector random activity to ensure identifiability.

An analytical procedure is described for synthesis and stability assessment of control systems for adaptive flyingqualities adherence with linear and nonlinear aircraft dynamics. This procedure directly incorporates desired loworder equivalent system (LOES) frequency and damping parameter values into the synthesis of control laws khat provide optimal adherence to MIL-STD-1797A guidelines. The procedure is used to derive a longitudinal control law for a contemporary fighter aircraft. Simulation results are presented. it is believed that this approach offers improved flying qualities and may be suitable for mitigation of pilot induced oscillation problems because its closed-loop phase lag is essentially that of the LOES specification.