Determination of Bounds on Performance Measure and Min-Max Controllers in Time-Lag Systems

The effect of bounded deterministic disturbances (external and/or internal) on a chosen performance index (PI) is investigated. Upper and lower bounds of the PI about a nominal value are determined by the application of the optimum control theory. A computational procedure is also proposed to determine an approximately optimal feedback controller for time-lag systems. Such a controller is designed here on the basis of min-max criteria. Numerical examples illustrate the proposed approach.     

Comparisons of Sensitivity Improvement Techniques for Linear Optimal Control Systems

It is well known that there are several ways to define a sensitivity function in the time domain. The results are reported of a study in which these definitions are compared. Controllers designed on the basis of these sensitivity functions are related to each other and conclusions are drawn about their usefulness in control system design.     

Low-Sensitivity Design of Optimal Linear Control Systems

The quadratic performance criterion, linear optimal control problem is reformulated to incorporate constraints on trajectory sensitivity. The open-loop solution is obtained for sensitivity functions defined for small plant-parameter variations. This approach has provided a beginning for other attempts to solve the low-sensitivity analytical design problem, as reported in the references.