Robustness of Model Reference Adaptive Schemes with Respect to Modeling Errors.

摘要

The robustness of model reference adaptive schemes with respect to unmodeled parasitics is analyzed. Bounds on parameter and state errors are established for identifiers and adaptive observers. In the case of adaptive control, algorithms are modified to guarantee boundedness. Decentralized adaptive control schemes guaranteeing the stability of a class of large-scale systems are proposed. This thesis is divided into six sections. Different characterizations are given for the model-plant mismatch in Sections 2 to 5 and 6. The characterization in Sections 2 to 5 assumes a separation of time scales between the modeled and unmodeled phenomena. The order of the model is equal to the order of the slow part of the unknown plant and the model-plant mismatch is due to the fast part of the plant. In most applications the slow part consists of dominant modes, while the neglected fast modes are considered as parasitics. The approach is asymptotic. In Section 6 the model-plant mismatch is characterized by neglected interconnections between different subsystems. Adaptive schemes are first designed for the decoupled subsystems and then applied to the overall system with the interconnections.