Variable structure model reference adaptive control systems

Abstract

Model reference adaptive controllers, when only input and output measurements are available, are designed using the theory of variable structure systems. State variable filters are used in order to obtain differentiator-free controllers. The proposed design allows the error transient to be prescribed in advance. The drawbacks deriving from the typical high-frequency chattering of the control signal during the sliding motion can be partially eliminated by means of a little modification of the adaptation law that does not cause the error signal to deteriorate considerably.