TABLE OF CONTENTS Oluwafemi Taiwo
Abstract. Two case studies of robust matching are reviewed in this chapter. One relates to systems with recycle and the other to the brake control of a heavy-duty truck. For the recycle system, a combination of design criteria for vague infinite-dimensional plants together with a special compensator for plants with recycle, is exploited to design a controller for a plant with recycle when the parameters of the process in the recycle path are subject to variations. The method gives a control system with guaranteed performance for large variations in process parameters. On the other hand, the problems encountered while designing a robust controller for the braking system of a heavy-duty truck include vagueness in the input function, variations in the plant parameters and the presence of dead time. Moreover, the system is critical. Appropriate design criteria are used to guarantee desired performance despite these difficulties.
In this chapter, two applications of Zakian's (1984, 1996) design framework to vague systems are reviewed. In previous work, delayed and retarded control systems (Bada 1987 and Taiwo 1986), were designed to be robustly matched to their respective environments. These works are reviewed here. Plant vagueness in both cases is caused by variations in dead times and plant gains that are not known precisely but are known only to be in a certain range.
Recycle operation is commonplace in the process industries and often leads to considerable deterioration of plant dynamics (Denn and Lavie 1982, Taiwo...
