Adaptive systems research in the NASA

The past contributions of NASA to adaptive control technology is reviewed. The review places emphasis on aircraft applications although spacecraft and launch vehicle control applications are included. Particular emphasis is given to the adaptive control system used in the X-15 research aircraft. Problem areas that limited the realizable performance of this adaptive system are discussed. Current technological capabilities are used to extrapolate the present-day potential for adaptive flight control. Specifically, the potential created by use of the modern high-speed digital computer in flight control is discussed. Present plans for research in digital adaptive control systems for the NASA F8-C digital fly-by-wire program are presented. These plans are currently envisioned to include research in at least two types of adaptive controls, the system identification/on-line design type, and the model reference type. The former type is expected to provide spin-off in other important experimental test programs. One spin-off relates to the use of online system identification to improve flight-test procedures. Another relates to the use of self-reorganizing control concepts to establish an on-line design capability that takes advantage of the maximum level of redundancy provided by the entire aircraft control system. This plan would make the flight control system optimally tolerant of system failures in both sensors and actuators.