Generation of Multilevel Control and Estimation Schemes for Large-Scale Systems: A Perturbational Approach

A new approach to the development of multilevel control and estimation schemes for large-scale systems with a major emphasis on the reliability of performance under structural perturbations is described. The study is conducted within a decomposition-decentralization framework and leads to simple and noniterative control and estimation schemes. The solution to the control problem involves the design of a set of locally optimal controllers for the individual subsystems in a completely decentralized environment and a global controller on a higher hierarchical level that provides corrective signals to account for the interconnection effects. Similar principles are employed to develop an estimation scheme, which consists of a set of decentralized optimal estimators for the subsystems, together with certain compensating signals for measurements. The principal feature of the paper is a detailed study of the system structure and the consequent classification of interconnection patterns into several interesting categories (beneficial, nonbeneficial, and neutral) based on their effects on decentralized control and estimation.