Accession Number : ADA293520

Title :   New Adaptive Methods for Reconfigurable Flight Control Systems. Appendix 2.

Descriptive Note : Final rept. 1 Jul 92-31 Dec 94,

Corporate Author : CARNEGIE-MELLON UNIV PITTSBURGH PA

Personal Author(s) : Bodson, Marc

PDF Url : ADA293520

Report Date : 15 FEB 1995

Pagination or Media Count : 174

Abstract : The report discusses methods for the design of reconfigurable flight control systems. Model reference adaptive control algorithms were developed which allow for the rapid identification of aircraft parameters after failures or damages and for automatic control redesign. These algorithms are simple enough that they can be implemented in real-time with existing computers. Simulation results were obtained using a detailed nonlinear model of a fighter aircraft. The results demonstrate the ability of the adaptive algorithms to automatically readjust trim values after failures, to restore tracking of the pilot commands despite the loss of actuator effectiveness and to coordinate the use of the remaining surfaces in order to maintain the decoupling between the rotational axes. The report also discusses analytical results that were obtained during the course of the research regarding the stability and convergence properties of multivariable adaptive control algorithms, the use of averaging methods for the analysis of transient response and robustness, and the estimation of uncertainty in dynamic models. A modified recursive least-squares algorithm with forgetting factor is also described which gives fast adaptation under normal conditions while keeping the sensitivity to noise limited when signal to noise ratios are poor.

Descriptors :   *FLIGHT CONTROL SYSTEMS, MATHEMATICAL MODELS, ALGORITHMS, CONTROL, SIMULATION, TRANSIENTS, FIGHTER AIRCRAFT, UNCERTAINTY, ADAPTIVE CONTROL SYSTEMS, AIRCRAFT, MODELS, COMPUTERS, DYNAMICS, PARAMETERS, MULTIVARIATE ANALYSIS, SIGNAL TO NOISE RATIO, TRACKING, SENSITIVITY, ESTIMATES, IDENTIFICATION, NONLINEAR SYSTEMS, RESPONSE, RECURSIVE FUNCTIONS, LEAST SQUARES METHOD, AXES, ADAPTIVE SYSTEMS, CONVERGENCE, LOSSES, ACTUATORS, VALUE, NOISE, ADAPTATION, ROTATION, AUTOMATIC.

Subject Categories : Flight Control and Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE