795establish initial convergence, the primary control system was engaged and a series of inputs was applied to demonstrate the performance of the adaptation logic. The pilot was not given an indication of angle of bank during the r u n , This resulted in a rolling supersonic dive ( M = 1.03). The altitude transition during the run was from 20 OOO to So00 ft. As in the longitudinal case, the performance of the adaptive system can be observed during the time intervals when the system is engaged. The uniformity of the roll rate response during engagement can be observed by comparing the steady-state roll rate at 20, 60, 80, and 1 0 0 s. Note the variability of the steady-state roll rate during time intervals where the primary control system is not engaged (e.%. at 5, 40, and 120 s). Note also that the surface commands required to realize the uniform roll rate responses vary considerably during the run. During the run, inputs were also made in rudder to examine the dutch roll adaptation characteristics. The dutch roll mode is observed to maintain a 0.7 damping ratio by examining the sideslip angle response to rudder inputs at times of 30,63, 83, and 110 s. These can be compared with the unaugmented responses at 10 and 50 s.
IV. CONCLUSIONSThis paper describes the moving window adaptive control concept whch has been developed as a candidate for flight test on the NASA FI-DFBW aircraft. Included are studies of the effects of auxiliary dither inputs to aid identification, data base size, measurement noise, and other design considerations. Results were presented indating the performance of the system in a nonlinear six-degee-of-freedom simulation of an F-8C aircraft. This study has shown that when there is sufficient motion of the aircraft, the adaptive algorithm converges to a h e a r mathematical model of the aircraft. Furthermore, it was shown that once these parameters have passed specified convergence criteria they may be used in an algebraic calculation of feedback and feedforward gains which satisfy certain flying quality requirements. Extensive simulation studies must be made before the moving window parameter adaptive control system can be recommended for flight test; however, results presented here indicate that the system is promising and should be evaluated further. One item requiring further evaluation and possible modification is the suitability of the mode of operation of the process without dither. REFERENCES J. R. Elliott, "NASA's advanced control law program for the F-8 digital fly-by-wire J. L. Picon. "Design of a digital adaptive control system for atmospheric reentry aircraft" this issue, pp. 753-757.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.