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This paper examines the robustness properties of existing adaptive control algorithms to unmodeled plant high-frequency dynamics and unmeasurable output disturbances. It is demonstrated that there exist two infinite-gain operators in the nonlinear dynamic system which determines the time-evolution of output and parameter errors. The pragmatic implication of(More)
A new control design methodology is introduced for multi-input/multi-output systems with unstable open loop plants and saturating actuators. A control system is designed using well known linear control theory techniques and then a reference prefilter is introduced so that when the references are sufficiently small, the control system operates linearly as(More)
—The paper considers a family of linear time-invariant and spatially-invariant (LTSI) systems that are both distributed and localized. The spatial responses of the distributed plant are localized in spatial neighborhoods of each location. The feedback computations are also distributed and the information flow is localized in a spatial neighborhood of each(More)
A systematic control design methodology is introduced for multi-input/multi-output stable open loop plants with multiple saturations. This new methodology is a substantial improvement over previous heuristic single-input/single-output approaches. The idea is to introduce a supervisor loop so that when the references and/or disturbances are sufficiently(More)
1. INTRODUCTION This paper reports the outcome of an exhaustive analyt-Due to space limitations we cannot possibly provide in ical and numerical investigation of stability and ro-this paper analytical and simulation evidence of all bustness properties of a wide class of adaptive control conclusions outlined in the abstract. Rather, we algorithms in the(More)
The preceding argument can be used to justify an infrequent The paper presents a frequency-domain estimator which can control-law redesign strategy. It is envisioned that a identify both a nominal model of a plant as well as a discrete-time estimator will be used to continually update the frequency-domain bounding function on the modeling error(More)
— This work develops control design technology for active shape control of reflective surfaces using large spatially distributed actuator arrays. The potential applications are in astronomy , adaptive optic, beam control, space-based imaging, and other optics and imaging applications. In a very large lightweight active reflector, surface shape (figure)(More)
— The paper considers one of the fundamental issues in design and analysis of sampled multidimensional systems-that of uncertainty modeling and robust stability analysis. Methods of structured uncertainty analysis (µ-analysis) are extended towards systems with dynamical and non-causal spatial coordinates. The stability is understood in a broad sense and(More)