Hierarchical Adaptive Control System Design and Application

Abstract This paper presents a new adaptive hierarchical control technique that adjusts its structure in order to maintain good performance over a wide variation of plant operating conditions. In contrast to the conventional approach of designing a compensator based upon a single control algorithm, this method combines a range of control algorithms in a complementary manner, each of which makes different assumptions about the regulated process. The hierarchical control structure includes a fuzzy controller which requires little process knowledge in order to provide an effective control, a multiple model adaptive controller which provides credible performance when the model bank adequately spans the expected plant variations and the plant behaves reasonably close to the model on which the compensator design was based, and a direct model reference adaptive controller which assumes that the plant transfer function satisfies specific sufficiency conditions. This paper presents an application of the hierarchical control structure as a regulator for a drug delivery system.